Research activity information

• Microstructural changes in carbonized wood-lignin, a potential space material, in response to atomic oxygen irradiation

  Toshimitsu Hata, Sensho Honma, Takeshi Kajimoto, Kyoichi Oshida, Yuki Tobimatsu, Masahito Tagawa, Hirotsugu Kojima, Subyakto

  Springer Science and Business Media LLC, Oct. 2023, Biomass Conversion and Biorefinery

  Scientific journal


• Anisotropic molecular scattering at microstructured surface for rarefied gas compression inside air breathing ion engine

  Kosuke Shoda, Naoki Kano, Yuki Jotaki, Keisuke Ezaki, Kazuki Itatani, Takashi Ozawa, Yusuke Yamashita, Kazutaka Nishiyama, Kumiko Yokota, Masahito Tagawa

  Springer Science and Business Media LLC, Mar. 2022, CEAS Space Journal

  Scientific journal


• Effect of atomic hydrogen exposure on hydrogenated amorphous carbon thin films

  Yuichi Haruyama, Daiki Morimoto, Akira Heya, Koji Sumitomo, Seigo Ito, Kumiko Yokota, Masahito Tagawa

  The effect of atomic hydrogen exposure on hydrogenated amorphous carbon (a-C:H) films was investigated by X-ray photoelectron spectroscopy (XPS). From the dependence of the wide-scan XPS spectra of an a-C:H film on atomic hydrogen exposure, it was shown that the film was etched with an etching rate of 0.2 nm min-1. In addition, by analyzing the C 1s XPS spectra, the coordination of C atoms in the a-C:H film was investigated as a function of the atomic hydrogen exposure and photoelectron emission angle. This indicated that the coordination of C atoms at the surface of the a-C:H film was not influenced by atomic hydrogen exposure. Therefore, we propose that the depth profile of a-C:H films can be measured with no damage using atomic hydrogen etching.

  {IOP} Publishing, Dec. 2021, Japanese Journal of Applied Physics, 60(12) (12)

  Scientific journal


• Effect of simultaneous N-2 collisions on atomic oxygen-induced polyimide erosion in sub-low Earth orbit: comparison of laboratory and SLATS data

  Kumiko Yokota, Masahito Tagawa, Yusuke Fujimoto, Wataru Ide, Yugo Kimoto, Yuta Tsuchiya, Aki Goto, Kazuki Yukumatsu, Eiji Miyazaki, Shunsuke Imamura

  The role of N₂ in the upper atmosphere on the atomic oxygen (AO)-induced erosion of polyimide in low Earth orbit (LEO) and sub-LEO is investigated through ground-based experiments and flight data. The experiment is performed by adding an Ar beam at the same collision energy as an undecomposed O₂ component in the AO beam formed by laser detonation to simulate the physical effect of simultaneous N₂ collision in sub-LEO. The Ar beam is added by the dual-pulsed supersonic valve-equipped laser-detonation system developed at Kobe University. The experimental results indicate that the erosion of polyimide in the laser-detonation system is promoted by the presence of O₂ and Ar in the beam, corresponding to N₂ in the sub-LEO. On-ground experimental results are compared with in-orbit AO measurements. Previous space shuttle, international space station-based exposure experiments, as well as the world’s first real-time sub-LEO material erosion data aboard a super low altitude test satellite (SLATS) orbiting at an altitude of 216.8 km are presented. The SLATS data suggests the presence of an acceleration effect by N₂ collision on AO-induced polyimide erosion, as predicted by ground-based experiments.

  SPRINGER WIEN, Jul. 2021, CEAS SPACE JOURNAL, 13(3) (3), 389 - 397, English

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Laser-detonation hyperthermal beam source applicable to VLEO environmental simulations

  Masahito Tagawa, Ryota Okura, Wataru Ide, Sasuga Horimoto, Keisuke Ezaki, Atsushi Fujita, Kosuke Shoda, Kumiko Yokota

  A more detailed understanding of the role of N2 in very low Earth orbit (VLEO) on atomic oxygen (AO)-induced material erosion is necessary for future development of the sub-LEO region. Accordingly, a laser-detonation source capable of capturing two different beams is developed. A dual-pulsed supersonic valve (dual-PSV) system is designed to form two beams in one nozzle configuration. It is demonstrated that the dual-PSV is capable of forming two atomic beams at individual energies with various composition ratios. This system is successfully applied for a ground-based simulation of the world’s first material erosion experiment in a sub-LEO aboard Super Low Altitude Test Satellite (SLATS).

  Springer, 2021, CEAS Space Journal, English

  Scientific journal


• Investigation and experimental simulation of performance deterioration of microwave discharge ion thruster μ10 during space operation

  Ryo Shirakawa, Yusuke Yamashita, Daiki Koda, Ryudo Tsukizaki, Yusuke Shimizu, Masahito Tagawa, Kazutaka Nishiyama

  © 2020 IAA In space operation of the microwave discharge ion thruster μ10 on the asteroid explorers Hayabusa and Hayabusa2, the propellant utilization efficiency deteriorated much more than in the ground endurance test. In this study, a fault tree analysis and experimental simulations of space operation were performed, focusing on the grid-derived internal carbon contamination. It was found that the performance deterioration due to the waveguide contamination matched that in Hayabusa2 qualitatively and quantitatively. Based on the experimental verification, the future performance is experimentally predicted.

  Sep. 2020, Acta Astronautica, 174, 367 - 376

  Scientific journal


• Investigation and experimental simulation of performance deterioration of microwave discharge ion thruster mu 10 during space operation

  Ryo Shirakawa, Yusuke Yamashita, Daiki Koda, Ryudo Tsukizaki, Yusuke Shimizu, Masahito Tagawa, Kazutaka Nishiyama

  In space operation of the microwave discharge ion thruster mu 10 on the asteroid explorers Hayabusa and Hayabusa2, the propellant utilization efficiency deteriorated much more than in the ground endurance test. In this study, a fault tree analysis and experimental simulations of space operation were performed, focusing on the grid-derived internal carbon contamination. It was found that the performance deterioration due to the wave-guide contamination matched that in Hayabusa2 qualitatively and quantitatively. Based on the experimental verification, the future performance is experimentally predicted.

  PERGAMON-ELSEVIER SCIENCE LTD, Sep. 2020, ACTA ASTRONAUTICA, 174, 367 - 376, English

  Scientific journal


• 宇宙機近傍プラズマ現象の数値シミュレーション

  三宅洋平, 臼井英之, 桐山武士, 白川遼, 田川雅人

  Sep. 2019, 混相流, 33(3) (3), 258 - 266, Japanese

  [Refereed]

  Scientific journal


• Enhancement of atomic oxygen resistance of charge dissipative ion beam treated polymers

  Z. Iskanderova, J. Kleiman, F. Bussieres, M. Tagawa, R. Ng, R. Sodhi

  Oct. 2018, 14th International Symposium on Materials in the Space Environment/12th International Conference on protection of Materials and Structures in a Space Environment, English

  [Refereed]

  International conference proceedings


• Evaluation of vacuum transfer vessel performance to construct cluster type in-situ test facilities network

  Alexandre SIMON, Minoru IWATA, Masahito TAGAWA, Sumitaka TACHIKAWA

  Oct. 2018, 14th International Symposium on Materials in the Space Environment/12th International Conference on protection of Materials and Structures in a Space Environmen, English

  [Refereed]

  International conference proceedings


• Over-estimation of atomic oxygen fluences due to undecomposed oxygen molecules included in hyperthermal beams

  Masahito Tagawa, Kazuki Kita, Ryota Okura, Yusuke Fujimoto, Ryo Shirakawa, Teppei Shimizu, Minoru Iwata

  Oct. 2018, 14th International Symposium on Materials in the Space Environment/12th International Conference on protection of Materials and Structures in a Space Environment, English

  [Refereed]

  International conference proceedings


• One-nozzle two-beam laser-detonation system

  Kumiko Yokota, Kazuki Kita, Ryota Okura, Teppei Shimizu, Sze Keat Chee, Minoru Iwata, Masahito Tagawa

  Oct. 2018, 14th International Symposium on Materials in the Space Environment/12th International Conference on protection of Materials and Structures in a Space Environment, English

  [Refereed]

  International conference proceedings


• Plasma particle simulation of ECR plasma generation in Air Breathing Ion Engine (ABIE

  Ryo Shirakawa, Hideyuki Usui, Yohei Miyake, Masahito Tagawa, Kazutaka Nishiyama

  May 2018, Proceedings of the 15th Spacecraft Charging Technology Conference, 55th, English

  International conference proceedings


• Development of a Pulsed Supersonic Valve Aimed for Martian Atmospheric Simulation

  Ryota Okura, Yusuke Fujimoto, Kazuki Kita, Minoru Iwata, Chee Sze Keat, Yugo Kimoto, Kumiko Yokota, Masahito Tagawa

  May 2018, Proceedings of the 15th Spacecraft Charging Technology Conference, English

  International conference proceedings


• A Consideration of Degradation of Polymeric Materials in Sub-Low Earth Orbit Space Environmen

  Yusuke Fujimoto, Ryota Okura, Kazuki Kita, Minoru Iwata, Kumiko Yokota, Masahito Tagawa

  May 2018, Proceedings of the 15th Spacecraft Charging Technology Conference, English

  International conference proceedings


• Soft X-ray irradiation effect on the fluorinated DLC film

  Hiroki Takamatsu, Masahito Niibe, XiaoLong Zhou, Keiji Komatsu, Hidetoshi Saitoh, Hiroki Akasaka, Akihiro Saiga, Koji Tamada, Masahito Tagawa, Kumiko Yokota, Yuichi Furuyama, Kazuhiro Kanda

  The irradiation effect on fluorinated diamond-like carbon (F-DLC) film was investigated by measuring the dose dependence of various film properties using synchrotron radiation (SR) in the soft X-rays in the SR dose region from 0 to 2000 mA h. Film flatness was maintained but various film properties and surface properties were found to be changed by the SR irradiation. Wettability of the F-DLC film surface increased dramatically within 20 mA h SR exposure, which was ascribed to the decrease in fluorine on the film surface. Film thickness, film density, composition ratio of fluorine atom in film decreased and sp(2) / (sp(2) + sp(3)) ratio of carbon atoms increased within 300 mA h SR exposure, which were ascribed to the desorption of species containing fluorine atoms. In addition, dominant desorbed species emitted from F-DLC film were found in the fluorocarbon group, CFx. Changes in film properties and film thickness did not proceed, when fluorine content in the F-DLC film decreased to about 10% after the 300 mA h SR exposure.

  ELSEVIER SCIENCE SA, Oct. 2017, DIAMOND AND RELATED MATERIALS, 79(1) (1), 14 - 20, English

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• A consideration on degradation of FEP-based radiator equipped to low altitude spacecraft,

  Masahito Tagawa, Yusuke Fujimoto, Kazuki Kita, Kumiko Yokota

  Sep. 2017, European 21st Thermophysical Properties Conference,, English

  Symposium


• Molecular beam source for degradation studies of polyimide-based thermal blanket in very low altitude space environment

  Kumiko Yokota, Ryota Okura, Chee Sze Keat, Masahito Tagawa

  Sep. 2017, 21st European Thermophysical Properties Conference,, English

  Symposium


• Collision-induced enhancement of polyimide corrosion in sub-low Earth orbit (LEO) space environment

  Masahito Tagawa, Ryota Okura, Yusuke Fujimoto, Kazuki Kita, Kumiko Yokota

  Aug. 2017, 33rd European Conference on Surface Science,, English

  Symposium


• A consideration on surface corrosion mechanism of fluoroethylenepropylene (FEP) films in sub-low earth orbit (LEO) environment

  Kumiko Yokota, Yusuke Fujimoto, Ryota Okura, Kazuki Kita, Masahito Tagawa

  Aug. 2017, 33rd European Conference on Surface Science,, English

  Symposium


• Accelerating effect of atomic oxygen-induced polyimide degradation due to simultaneous collision of chemically inert molecules

  Kazuki Kita, Yusuke Fujimoto, Yuki Yamasaki, Minoru Iwata, Kumiko Yokota, Masahito Tagawa

  Jun. 2017, 31st International Symposium on Space Technology and Science,, English

  International conference proceedings


• Mass-loss of FEP/Ag films in sub-low Earth orbit space environment

  Yusuke Fujimoto, Kazuki Kita, Yasuko Koshiba, Kenji Ishida, Minoru Iwata, Kumiko Yokota, Masahito Tagawa

  Jun. 2017, 31st International Symposium on Space Technology and Science,, English

  International conference proceedings


• A pulsed supersonic valve aimed for Martian atmospheric simulation

  Ryota Okura, Minoru Iwata, Chee Sze Keat, Kumiko Yokota, Masahito Tagawa

  Jun. 2017, 31st International Symposium on Space Technology and Science,, English

  International conference proceedings


• Variation in film properties of fluorine containing DLC film by exposure to soft X-rays

  Takamatsu Hiroki, Kanda Kazuhiro, Miura Eri, Akasaka Hiroki, Saiga Akihiro, Tamada Koji, Tagawa Masahito, Yokota Kumiko, Furuyama Yuichi

  The Japan Society of Applied Physics, Mar. 2017, JSAP Annual Meetings Extended Abstracts, 2017.1, 1364 - 1364, Japanese


• Hyperthermal multiple component molecular/atomic beams: Formation and application to surface science on future space explorations,

  Tsubasa Yasukochi, Kaoru Morimoto, Kumiko Yokota, Masahito Tagawa

  Jan. 2017, Symposium on Surface Science & Nanotechnology -25th Anniversary of SSSJ Kansai, English

  International conference proceedings


• オーガナイズドセッション：先進材料の熱物性と宇宙システムデザイン

  岩田稔, 長野方星, 太刀川純孝, 田川雅人

  Jan. 2017, 熱物性, 31(1) (1), English

  [Refereed]

  Scientific journal


• 宇宙環境工学の観点から見たSLATSへの期待

  田川雅人, 井出健太, 山崎勇希, 北一貴, 横田久美子

  Dec. 2016, 超低高度衛星の利用に向けたワークショップ報告書, JAXA-SP-16-001, Japanese

  [Refereed]

  Symposium


• Extreme ultraviolet emission from laser-induced O2+Ar plasmas relevance to ground-based simulation of thin film etching reactions in low Earth orbit

  Masahito Tagawa, Takashi Ohyabu, Junki Ohira, Kaoru Morimoto, Kumiko Yokota

  Dec. 2016, Pacific Rim Symposium on Surfaces, Coatings and Interfaces,, English

  Symposium


• A pulsed supersonic valve system for researches on collision-induced reactive thin film etching phenomena

  Masahito Tagawa, Kumiko Yokota, Tsubasa Yasukochi, Chee Sze Keat

  Dec. 2016, Pacific Rim Symposium on Surfaces, Coatings and Interfaces,, English

  Symposium


• Atomic oxygen-induced erosion property of polyimide-based multilayer insulation in very low altitude

  Kumiko Yokota, Yuki Yamasaki, Kazuki Kita, Masahito Tagawa

  Oct. 2016, 11th Asia Thermophysical Properties Conference,, English

  Symposium


• Extreme ultraviolet emission from laser-induced plasma relevance to neutral gas environment simulation in low Earth orbit

  Kumiko Yokota, Masahito Tagawa

  Jun. 2016, 16th Joint Vacuum Conference, 14th European Vacuum Conference,, English

  Symposium


• A fast piezoelectric-driven pulsed supersonic valve using displacement enlargement mechanism for molecular beam applications

  Masahito Tagawa, Kumiko Yokota, Chee Sze Keat

  Jun. 2016, 16th Joint Vacuum Conference, 14th European Vacuum Conference,, English

  Symposium


• Resistance of Hydrogenated Titanium-Doped Diamond-Like Carbon Film to Hyperthermal Atomic Oxygen

  Kengo Kidena, Minami Endo, Hiroki Takamatsu, Masahito Niibe, Masahito Tagawa, Kumiko Yokota, Yuichi Furuyama, Keiji Komatsu, Hidetoshi Saitoh, Kazuhiro Kanda

  MDPI AG, Dec. 2015, METALS, 5(4) (4), 1957 - 1970, English

  Scientific journal


• Hyperthermal atomic oxygen beam irradiation effect on the hydrogenated Si-doped DLC film

  Kengo Kidena, Minami Endo, Hiroki Takamatsu, Ryo Imai, Masahito Niibe, Kumiko Yokota, Tagawa Masahito, Yuichi Furuyama, Keiji Komatsu, Hidetoshi Saitoh, Kazuhiko Kanda

  2015, Trans. Mat. Res. Soc. Japan, 40(4) (4), 353 - 358, English

  [Refereed]

  Scientific journal


• Multiple-composition hyperthermal atomic beams formed by a laser-induced plasma for planetary environmental studies

  Kumiko Yokota, Daiki Watanabe, Junki Ohira, Masahito Tagawa

  A multiple-composition beam with a velocity of 8 km s(-1) was formed using a laser detonation source in order to simulate the physical and chemical effects of neutral gas collisions on a material in the sub-low earth orbit (LEO). A premixed target gas was applied in the laser detonation beam technique. It was found that atoms of different masses, O and Ar for Ar + O-2 target gas, are accelerated to similar velocities, i.e. different translational energies. Promotion of O-2 decomposition is confirmed by using a mixed gas target. It is concluded that the multiple-composition beam obtained using a mixed target gas is suitable for simulating a neutral gas environment in the sub-LEO region.

  IOP PUBLISHING LTD, May 2014, PHYSICA SCRIPTA, T161, USB, English

  Scientific journal


• Multiple-composition hyperthermal atomic beams formed by a laser-induced plasma for planetary environmental studies

  Kumiko Yokota, Daiki Watanabe, Junki Ohira, Masahito Tagawa

  A multiple-composition beam with a velocity of 8 km s(-1) was formed using a laser detonation source in order to simulate the physical and chemical effects of neutral gas collisions on a material in the sub-low earth orbit (LEO). A premixed target gas was applied in the laser detonation beam technique. It was found that atoms of different masses, O and Ar for Ar + O-2 target gas, are accelerated to similar velocities, i.e. different translational energies. Promotion of O-2 decomposition is confirmed by using a mixed gas target. It is concluded that the multiple-composition beam obtained using a mixed target gas is suitable for simulating a neutral gas environment in the sub-LEO region.

  IOP PUBLISHING LTD, May 2014, PHYSICA SCRIPTA, T161(161) (161), English

  [Refereed]

  Scientific journal


• Multiple-composition hyperthermal atomic beams formed by a laser-induced plasma for planetary environmental studies

  Kumiko Yokota, Daiki Watanabe, Junki Ohira, Masahito Tagawa

  A multiple-composition beam with a velocity of 8 km s-1 was formed using a laser detonation source in order to simulate the physical and chemical effects of neutral gas collisions on a material in the sub-low earth orbit (LEO). A premixed target gas was applied in the laser detonation beam technique. It was found that atoms of different masses, O and Ar for Ar + O2 target gas, are accelerated to similar velocities, i.e. different translational energies. Promotion of O2 decomposition is confirmed by using a mixed gas target. It is concluded that the multiple-composition beam obtained using a mixed target gas is suitable for simulating a neutral gas environment in the sub-LEO region. © 2014 The Royal Swedish Academy of Sciences.

  Institute of Physics Publishing, 2014, Physica Scripta, T161, English

  [Refereed]

  International conference proceedings


• Hyperthermal atomic oxygen beam irradiation effect on the Ti-containing DLC film

  Kazuhiro Kanda, Kazuhiro Fukuda, Kengo Kidena, Ryo Imai, Masahito Niibe, Synya Fujimoto, Kumiko Yokota, Masahito Tagawa

  Surface structural changes of Ti-doped diamond-like carbon (Ti-DLC) film exposed to a hyperthermal atomic oxygen beam were investigated using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy using synchrotron radiation. The spectral shape of the C K NEXAFS spectrum of as-deposited Ti-DLC film resembled that of DLC film. After exposure to atomic oxygen, the spectrum resembled that of TiC powder. The sp(2)/(sp(2) + sp(3)) ratio of as-deposited Ti-DLC film decreased drastically by exposure to a hyperthermal atomic oxygen beam. On the other hand, the spectral shape in the Ti L NEXAFS spectrum of as-deposited Ti-DLC film resembled that of TiC powder and became similar to that of TiO2 powder after exposure to atomic oxygen. These changes are ascribable to the desorption of C atoms as CO and/or CO2 from Ti-DLC film due to the irradiation of atomic oxygen beam. On the other hand, oxidized Ti was not desorbed from the Ti-DLC film. As a result, the sp(2)/(sp(2) + sp(3)) ratio of C in the Ti-DLC film decreased, because residual C atoms were bonded to Ti atoms. (C) 2014 Published by Elsevier B.V.

  ELSEVIER SCIENCE SA, Jan. 2014, DIAMOND AND RELATED MATERIALS, 41, 49 - 52, English

  Scientific journal


• レーザーデトネーション法による低軌道宇宙環境地上シミュレーションとEUV

  Tagawa Masahito, Yokota Kumiko

  レーザー学会, 2014, レーザー研究, 42(1) (1), 50 - 54, Japanese

  [Refereed]

  Scientific journal


• オーガナイズドセッション：先進材料の熱物性と宇宙システムデザイン

  TAGAWA MASAHITO, TACHIKAWA SUMITAKA

  日本熱物性学会, 2014, 熱物性, 28(1) (1), 41, Japanese

  [Refereed]

  Research society


• Hyperthermal atomic oxygen beam irradiation effect on the Ti-containing DLC film

  Kazuhiro Kanda, Kazuhiro Fukuda, Kengo Kidena, Ryo Imai, Masahito Niibe, Synya Fujimoto, Kumiko Yokota, Masahito Tagawa

  Surface structural changes of Ti-doped diamond-like carbon (Ti-DLC) film exposed to a hyperthermal atomic oxygen beam were investigated using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy using synchrotron radiation. The spectral shape of the C K NEXAFS spectrum of as-deposited Ti-DLC film resembled that of DLC film. After exposure to atomic oxygen, the spectrum resembled that of TiC powder. The sp(2)/(sp(2) + sp(3)) ratio of as-deposited Ti-DLC film decreased drastically by exposure to a hyperthermal atomic oxygen beam. On the other hand, the spectral shape in the Ti L NEXAFS spectrum of as-deposited Ti-DLC film resembled that of TiC powder and became similar to that of TiO2 powder after exposure to atomic oxygen. These changes are ascribable to the desorption of C atoms as CO and/or CO2 from Ti-DLC film due to the irradiation of atomic oxygen beam. On the other hand, oxidized Ti was not desorbed from the Ti-DLC film. As a result, the sp(2)/(sp(2) + sp(3)) ratio of C in the Ti-DLC film decreased, because residual C atoms were bonded to Ti atoms. (C) 2014 Published by Elsevier B.V.

  ELSEVIER SCIENCE SA, Jan. 2014, DIAMOND AND RELATED MATERIALS, 41, 49 - 52, English

  [Refereed]

  Scientific journal


• Evaluation and application of the EUV emitted from a laser-detonation atomic oxygen space environmental simulator: FY2013 report

  TAGAWA MASAHITO, YOKOTA KUMIKO, Ohira Junki, Kimoto Yugo, Nishimura Hiroaki

  大阪大学レーザーエネルギー学研究センター, 2014, 大阪大学レーザーエネルギー学研究センター平成25年度共同利用・共同研究成果報告書, 171 - 172, Japanese

  Research institution


• Effect of Atomic Oxygen Irradiation on Field Emission Cathodes in Low Earth Orbit

  Shimada Atsuko, Tanaka Yoshinobu, Ohkawa Yasushi, Matsumoto Koji, Tagawa Masahito, Matsui Makoto, Yamagiwa Yoshiki

  An Electrodynamic tether (EDT) is an attractive propulsion device for active debris removal systems. One of the key components of the EDT system is an electron emission device, and we have studied a field emission cathode (FEC) using carbon nanotubes (CNTs) because of its simplicity and potential capabilities. Since EDT systems are operated in low earth orbit (LEO), the CNTs in the FEC may be affected by atomic oxygen (AO), so the effect of AO irradiation on the FEC was studied. We conducted AO irradiation tests on FECs using laser detonation beam facilities and compared the pre- and post-irradiation electron emission characteristics. As a result, the FEC could not emit electrons when the total AO fluence of 3×10²⁰ /cm² was irradiated perpendicular to the emission surface. In this case, CNTs on the emitter surface disappeared by AO irradiation. When the irradiation direction was parallel to the emission surface, on the other hand, the FEC could emit electrons after the irradiation although the required voltage increased up to 1.5 times as high as that of pre-irradiation condition. This comparison indicated that the direction of AO irradiation has strong effect on the performance degradation of the FEC on orbit.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2014, Aerospace Technology Japan, 12(29) (29), 59 - 64, English

  [Refereed]

  Scientific journal


• A synchrotron radiation photoelectron spectroscopic study on the oxidation of Si in diamond-like carbon film by hyperthermal O-atom beam

  Yokota Kumiko, Tagawa Masahito, Yoshigoe Akitaka, Teraoka Yuden

    Oxidation reaction efficiency of the embedded Si atoms in the diamond-like carbon (DLC) film was studied with a combination of the broad O-atom beam, high-speed chopper wheel and synchrotron radiation photoelectron spectroscopy (SR-PES). The high-speed chopper wheel converted the translational energy distribution of O-atom into spatial distribution on the DLC surface. High spatial and energy resolutions of SR-PES allow studying the difference in oxidation states of Si atoms in different translational energies. It was confirmed that the SiO₂ was formed by the high-energy collision conditions of O-atoms, whereas sub-oxides are formed with the low-energy collisions. The efficiency of SiO₂ formation at 9 eV-collision is evaluated to be 4 times greater than that at 2 eV-collision.

  The Surface Analysis Society of Japan, 2014, Journal of Surface Analysis, 20(3) (3), 221 - 225, English

  [Refereed]

  Scientific journal


• 非回収軌道上試験を目指した国産宇宙用QCMの特性と地上キャリブレーション法

  井出 健太, 山崎 勇希, 潮田 陽介, 西山 和孝, 横田 久美子, 田川 雅人

  第10回宇宙環境シンポジウム (2013年12月2日-3日. 科学技術館), 東京形態: カラー図版あり資料番号: AA0062301011レポート番号: JAXA-SP-13-016

  JAXA, Dec. 2013, 第10回宇宙環境シンポジウム, JAXA-SP(SP-13-016) (SP-13-016), 71 - 73, Japanese

  Research institution


• 大気吸入型イオンエンジン放電室内におけるプラズマ生成シミュレーション

  本山 貴仁, 臼井 英之, 三宅 洋平, 川口 伸一郎, 横田 久美子, 田川 雅人

  JAXA, Dec. 2013, 第10回宇宙環境シンポジウム, JAXA-SP(JAXA-SP-13-016) (JAXA-SP-13-016), 61 - 64, Japanese

  Research institution


• A Synchrotron Radiation Photoelectron Spectroscopic Study on the Oxidation Reaction of Si by O-atom with Collision Energies between 2 to 9 eV

  Kumiko Yokota, Masahito Tagawa, Akitaka Yoshigoe, Yuden Teraoka

  Nov. 2013, PSA-13, USB, English

  International conference proceedings


• Use of laser-induced plasmas for gas-surface interaction studies on Earth observation satellites

  Masahito Tagawa, Kumiko Yokota

  Sep. 2013, International Conference on Research and Applications of Plasmas, USB, English

  International conference proceedings


• Influence of 9 eV collision of chemically inert molecules on fluorinated polymer erosion in sub-low earth orbit

  Kumiko Yokota, Masahito Tagawa, Koji Matsumoto, Yuichi Furuyama, Akira Kitamura, Kazuhiro Kanda, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  Sep. 2013, 19th International Vacuum Congress,, USB, English

  International conference proceedings


• Influence of 5 eV collision of O-atoms on material erosions in low earth orbit space environment

  Masahito Tagawa, Kumiko Yokota

  Sep. 2013, 19th International Vacuum Congress,, USB, English

  International conference proceedings


• レーザー駆動酸素プラズマからの極端紫外線分光の試み

  田川 雅人, 横田 久美子, 島村 宏之, 木本 雄吾, 古賀 麻由子, 西村 博明

  公益社団法人 応用物理学会, Aug. 2013, 応用物理学会学術講演会講演予稿集, 2013.2, 2417 - 2417, Japanese


• Microwave Plasma Simulation for the Development of Air Breathing Ion Engine

  Takahito Motoyama, Hideyuki Usui, Yohei Miyake, Akihiko Hashimoto, Masahito Tagawa, Kumiko Yokota

  Aug. 2013, The 11th International School Symposium for Space Simulations, USB, English

  International conference proceedings


• Synergistic effect of atomic oxygen and vacuum ultraviolet on polymeric materials at various temperatures

  Yosuke Ushioda, Takaho Tsuboi, Kenta Ide, Masahito Tagawa, Kumiko Yokota, Akio Okamoto

  JSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, English

  International conference proceedings


• Sub-low Earth orbit neutral gas environment simulation using laser detonation beam source

  Takashi Ohyabu, Shigeru Yasuda, Masahito Tagawa, Kumiko Yokota

  JSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, English

  International conference proceedings


• Microwave plasma simulation for the development of air breathing ion engine

  Takahito Motoyama, Hideyuki Usui, Yohei Miyake, Kumiko Yokota, Masahito Tagawa

  JSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, English

  International conference proceedings


• Impact of high-energy collision of inert gas on the material degradation in space environment -Erosion properties in the hyperthermal multiple composition beams-

  Masahito Tagawa, Takashi Ohyabu, Shigeru Yasuda, Kumiko Yokota, Akio Okamoto

  JSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, English

  International conference proceedings


• Impact of high-energy collision of inert gas on the material degradation in space environment -Comparison of the ground-based data and MISSE-2 analysis-,

  Kumiko Yokota, Takashi Ohyabu, Shigeru Yasuda, Masahito Tagawa

  JSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, English

  International conference proceedings


• A ground-based simulation study for FEP erosion on the SLATS/MDM mission

  Shinji Fujimoto, Shigeru Yasuda, Daiki Watanabe, Kumiko Yokota, Masahito Tagawa, Yugo Kimoto, Junichiro Ishizawa

  JSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, English

  International conference proceedings


• Experimental Study of Air Breathing Ion Engine Using Laser Detonation Beam Source

  Masahito Tagawa, Kumiko Yokota, Kazutaka Nishiyama, Hitoshi Kuninaka, Yasuo Yoshizawa, Daisaku Yamamoto, Takaho Tsuboi

  The basic properties of an air breathing ion engine, which uses upper atmospheric gases as a propellant, were experimentally investigated. The N-2 environment in a sub-low Earth orbit (altitude of 140-200 kin) was simulated by a laser detonation beam source, which has been previously used in studies on atomic oxygen-induced material degradation. The basic properties of the air breathing ion engine were studied using a hyperthermal N-2 beam. It is suggested that the hyperthermal N-2 molecules thermalized by scattering at the reflector surface in the air breathing ion engine. The efficiency of the collimator was experimentally investigated and the collimator was found to maintain the N-2 pressure inside the air breathing ion engine. An ion beam current of 16 mA at an acceleration voltage of 200 V provided a thrust of 0.13 mN for both hyperthermal N-2 and atomic oxygen beams. The maximum ion beam current was found to be limited by the space-charge effect. The experimental results strongly indicated the recombination of atomic oxygen into O-2 molecules inside the air breathing ion engine.

  AMER INST AERONAUTICS ASTRONAUTICS, May 2013, JOURNAL OF PROPULSION AND POWER, 29(3) (3), 501 - 506, English

  [Refereed]

  Scientific journal


• “Evaluation and application of the EUV emitted from a laser-detonation atomic oxygen space environmental simulator: FY2012 report”, (2013), pp.195-196.

  Masahito Tagawa, Kumiko Yokota, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  ILE, Osaka University, May 2013, 大阪大学レーザーエネルギー学研究センター平成24年度共同利用・共同研究成果報告書, 195 - 196, English

  Research institution


• Hydrogen removal from hydrogenated diamond-like carbon films by photon and energetic atomic oxygen exposures

  Kumiko Yokota, Masahito Tagawa, Koji Matsumoto, Yuichi Furuyama, Akira Kitamura, Kazuhiro Kanda, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  Springer, Apr. 2013, Protection of Materials and Structure in a Space Environment, 531 - 541, English

  [Refereed]

  International conference proceedings


• Extreme ultraviolet emission form a carbon dioxide laser-sustained oxygen plasma

  Akira Mizutani, Kazuhiro Kishida, Kumiko Yokota, Masahito Tagawa, Hiroyuki Shimamura, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  Springer, Apr. 2013, Protection of Materials and Structure in a Space Environment, 547 - 556, English

  [Refereed]

  International conference proceedings


• Relative Electron Impact Ionization Probabilities of O, O-2, and Ar Components in Laser-Detonation Hyperthermal Beams

  Kumiko Yokota, Shigeru Yasuda, Akira Mizutani, Masahito Tagawa

  The relative ionization probabilities of laser-detonation hyperthermal O, O-2, and Ar components in Ar+O-2 mixed molecular beams were evaluated for investigation of the effect of the space environment. In a high-energy beam, the complete decomposition of O-2 was observed from the time-of-flight (TOF) spectra, which was due to high-energy collisions between O-2 and Ar. Relative ionization probabilities of O and O-2 of 0.27 and 0.79, respectively, with respect to Ar were evaluated by assuming the complete decomposition of O-2 in the beam. These values can be applied in studies on the effect of the space environment in the sub-low Earth orbit region where simultaneous hyperthermal N-2 and O bombardment should be simulated. (c) 2013 The Japan Society of Applied Physics

  IOP PUBLISHING LTD, Mar. 2013, JAPANESE JOURNAL OF APPLIED PHYSICS, 52(3) (3), 038002, English

  [Refereed]

  Scientific journal


• Extreme Ultraviolet Emission from Laser-Induced Plasma During Atomic Oxygen Tests

  Masahito Tagawa, Kazuhiro Kishida, Kumiko Yokota, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  AMER INST AERONAUTICS ASTRONAUTICS, Mar. 2013, JOURNAL OF SPACECRAFT AND ROCKETS, 50(2) (2), 460 - 462, English

  [Refereed]

  Scientific journal


• Use of one-side silver-coated FEP on slats/MDM mission for a mechanistic study of fluoropolymer erosion in LEO/super-LEO environments

  Kumiko Yokota, Shigeru Yasuda, Masahito Tagawa, Kazuhiro Aoyama, Eiji Miyazaki, Junichiro Ishizawa, Yugo Kimoto

  The origin of FEP (and other fluoropolymers) erosion in space environment is still in question atomic oxygen, UV or high-energy particle such as N2. In the recent ground-based study, role of high-energy impact of chemically inert atoms/molecules is addressed. In order to verify this ground-based result in space, materials test in super-low earth orbit, where N2 fraction is higher than conventional LEO, is conducted using an opportunity to carry FEP sample aboard super-low altitude test satellite (SLATS). Feasibility was evaluated to distinguish the origin of FEP erosion by comparing SLATS data at the altitude of 200 km and MISSE data at 400 km. Copyright © 2013 European Space Agency.

  2013, European Space Agency, (Special Publication) ESA SP, 705, English

  International conference proceedings


• Extreme ultraviolet emission from a carbon dioxide laser-sustained oxygen plasma

  Akira Mizutani, Kazuhiro Kishida, Kumiko Yokota, Masahito Tagawa, Hiroyuki Shimamura, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  © Springer-Verlag Berlin Heidelberg 2013. Extreme ultraviolet (EUV) spectrum emitted from laser-sustained oxygen plasma in a laser detonation atomic oxygen beam source was investigated. In order to measure EUV spectra, specially designed flat-field grazing-incidence EUV spectrometer was designed. The EUV spectra were recorded on an imaging plate which provides quantitative analysis capability. It was confirmed that EUV emission in the range of 20 –50 nm was included in the emission from laser-sustained oxygen plasma in a laser detonation source. The experimental results clearly indicated that the EUV intensity depends strongly on the translational energy of atomic oxygen. Even though the effect of EUV on the material erosion has not been confirmed, presence of high-energy photon need to be considered for better understanding of the reaction of hyperthermal atomic oxygen in the ground-based facility.

  2013, Astrophysics and Space Science Proceedings, 32, 587 - 596

  [Refereed]

  International conference proceedings


• Survivability of silicon-doped diamond-like carbon films in energetic atomic/molecular oxygen beam environments

  Masahito Tagawa, Kazuhiro Kishida, Kumiko Yokota, Akitaka Yoshigoe, Yuden Teraoka, Koji Matsumoto, Jianming Zhang, Timothy K. Minton

  Volatile products were measured from two types of diamond-like carbon films under the hyperthermal atomic oxygen (AO) beam bombardment. It was clearly observed that CO and CO2 were formed at the conventional hydrogenated DLC surface when exposed to hyperthermal AO beam. Desorption rates of CO and CO2 are constant with AO fluence which reflects the constant erosion rate of the hydrogenated DLC. In contrast, Si-doped DLC shows decrease in amount of CO and CO2 with increasing AO fluence. Oxidation of Si atoms at the DLC surface was detected by X-ray photoelectron spectroscopy, confirming the formation of SiO2 film formed at the DLC surface that could prevent AO reaction with C atoms in DLC which leads to loss of DLC. Since a self-healing capability can be expected on Si-doped DLC, metal doping is a promising technology for space application of DLC.

  Springer Netherlands, 2013, Astrophysics and Space Science Proceedings, 32, 547 - 556, English

  [Refereed]

  International conference proceedings


• Resistance of silicon-containing carbonized lignin to atomic oxygen erosion

  Takeshi Kajimoto, Toshimitsu Hata, Masahito Tagawa, Hirotsugu Kojima, Hajime Hayakawa

  Spacecraft in low Earth orbit (LEO) are exposed to atomic oxygen (AO). It is thus important to develop an environmentally friendly material that can be applied to the outer surfaces of spacecraft in LEO to protect them against AO. Carbonized material containing electroconductive graphitic microlayers is promising for this purpose. We produced carbonized lignin (CW) by separating wood in L-lactic acid and we investigated the AO erosion resistances of CW and CW containing Si. X-ray photoelectron spectroscopy (XPS) revealed that the O/C ratio increased on AO exposure. The CW sample without Si and CW samples containing 20% and 40% Si exhibited less erosion than CW samples containing 5% and 10% Si. XPS revealed that the presence of Si resulted in the formation of SiO2 on the sample surface. For CW with Si contents of 20% and 40%, the SiO2 coverage may be sufficiently large to prevent attack by AO.

  Springer Netherlands, 2013, Astrophysics and Space Science Proceedings, 32, 541 - 546, English

  [Refereed]

  International conference proceedings


• Interaction mechanism of soft X-rays with irradiated diamond-like carbon films

  Kazuhiro Kanda, Masahito Niibe, Kumiko Yokota, Masahito Tagawa

  The interaction mechanism of continuous soft X-rays with irradiated in vacuum diamond-like carbon (DLC) films, to simulate space environment conditions, was investigated using synchrotron radiation (SR). The thickness of the highly hydrogenated DLC film was found to decrease with increasing SR dose. The variation of local structure of DLC film was evaluated by measurements of the near edge X-ray absorption fine structure of carbon K-edge using SR. The characteristic peaks were observed in the spectrum of highly hydrogenated DLC film before irradiation, with these peaks disappearing from the spectrum after irradiation. These peaks are considered to be derived from the carbon bonding to hydrogen, which was desorbed by the soft X-ray irradiation. The sp2/(sp2 +sp3) ratio of DLC film was found to increase by the irradiation of soft X-ray.

  Springer Netherlands, 2013, Astrophysics and Space Science Proceedings, 32, 159 - 164, English

  [Refereed]

  International conference proceedings


• Microtribological properties of molybdenum disulfide bonded film exposed to space environment by SM/SEED mission

  Masahito Tagawa, Kumiko Yokota, Kunitaka Ochi, Masao Akiyama, Koji Matsumoto, Mineo Suzuki

  Macroscopic and microtribological properties of MoS2 films exposed to atomic oxygen, ultraviolet rays and radiation both in low earth orbit (LEO) and in ground-based facility were evaluated. The MoS2 samples are exposed to LEO space environment in the Space Environment Exposure Device (SEED) experiment on International Space Station (ISS). Laser-detonation atomic oxygen beam source was used for atomic oxygen simulation on the ground. It was found that the macroscopic friction coefficient of the flight sample was similar to that of the control sample. In contrast, remarkable increase in friction coefficient in microscopic properties was observed.

  Springer Netherlands, 2013, Astrophysics and Space Science Proceedings, 32, 577 - 586, English

  [Refereed]

  International conference proceedings


• Comparison of Macro and Microtribological Property of Molybdenum Disulfide Film Exposed to LEO Space Environment

  Masahito Tagawa, Kumiko Yokota, Kunitaka Ochi, Masao Akiyama, Koji Matsumoto, Mineo Suzuki

  Macro- and microtribological properties of the MoS(2) film exposed to atomic oxygen, ultraviolet rays and radiation both in low earth orbit (LEO) and in ground-based facility were evaluated relevance to micro/nano satellites. MoS(2) samples are exposed to LEO space environment by the space environment exposure device experiment on international space station. Laser-detonation atomic oxygen beam source was used for atomic oxygen simulation on the ground. X-ray photoelectron spectroscopy and energy dispersive spectroscopy measurements suggested that electron beam and ultraviolet exposure did not affect chemical structure of MoS(2) surfaces. However, atomic oxygen-exposed and flight samples showed surface oxidation. It was found that the macroscopic friction coefficient of the flight sample was similar to that of the control sample. In contrast, remarkable increase in friction coefficient in microscopic properties was observed.

  SPRINGER/PLENUM PUBLISHERS, Feb. 2012, TRIBOLOGY LETTERS, 45(2) (2), 349 - 356, English

  [Refereed]

  Scientific journal


• Use of one-side silver-coated FEP on SALTS/MDM mission for mechanistic study of fluoropolymer erosion in LEO

  Kumiko Yokota, Shigeru Yasuda, Masahito Tagawa, Kazuhiro Aoyama, Eiji Miyazaki, Yugo Kimoto

  2012, Proceedings of 12th International Symposium on Materials in Space Environment,, CD - ROM, English

  [Refereed]

  International conference proceedings


• Temperature effect on synergistic erosion of polyimide under simultaneous exposure conditions of atomic oxygen and vacuum ultraviolet

  Takaho Tsuboi, Yosuke Ushioda, Kumiko Yokota, Masahito Tagawa, Akio Okamoto

  2012, Proceedings of 12th Spacecraft Charging Technology Conference, CD - ROM, English

  [Refereed]

  International conference proceedings


• Origin of fluoropolymer erosion in low earth orbit space environment

  Masahito Tagawa, Kazuhiro Kishida, Akira Mizutani, Takashi Ohyabu, Kumiko Yokota, Akio Okamoto

  2012, Proceedings of 12th Spacecraft Charging Technology Conference, CD - ROM, English

  [Refereed]

  International conference proceedings


• Numerical Simulation of Microwave Plasma in Air Breathing Ion Engine

  Takahito Motoyama, Hideyuki Usui, Yohei Miyake, Akihiko Hashimoto, Masahito Tagawa, Kumiko Yokota

  2012, Extended Abstract on the International Conference on Simulation Technology 2012, English

  [Refereed]

  International conference proceedings


• Importance of beam-surface interactions on long-term missions of spacecraft in low planetary altitudes

  Masahito Tagawa, Kumiko Yokota, Kunitaka Ochi, Masao Akiyama, Koji Matsumoto, Mineo Suzuki

  2012, roceedings of JVC-14 / EVC-12 / AMDVG-11 / CroSloVM-19, CD - ROM, English

  [Refereed]

  International conference proceedings


• Formation of multiple-composition beam for super-LEO space environmental simulation”, Masahito Tagawa,

  Masahito Tagawa, Akira Mizutani, Shigeru Yasuda, Kumiko Yokota

  2012, Proceedings of 12th International Symposium on Materials in Space Environment,, CD - ROM, English

  [Refereed]

  International conference proceedings


• Formation of hyperthermal multiple composition beams for space environmental simulation in super low earth orbi

  Kumiko Yokota, Akira Mizutani, Shigeru Yasuda, Masahito Tagawa

  2012, roceedings of JVC-14 / EVC-12 / AMDVG-11 / CroSloVM-19, CD - ROM, English

  [Refereed]

  International conference proceedings


• Flight evaluation program on survivability of FEP in super-low earth orbit environment

  Kumiko Yokota, Masahito Tagawa, Kazuhiro Aoyama, Eiji Miyazaki, Yugo Kimoto

  2012, 64th International Astronautical Congress, CD - ROM, English

  [Refereed]

  International conference proceedings


• Effect of the Soft X-rays on Highly Hydrogenated Diamond-Like Carbon Films

  Kazuhiro Kanda, Kumiko Yokota, Masahito Tagawa, Mayumi Tode, Yuden Teraoka, Shinji Matsui

  The effect of soft X-ray irradiation of diamond-like carbon films in vacuum was investigated using synchrotron radiation (SR). Etching and the desorption of hydrogen upon SR exposure in vacuum occurred in highly hydrogenated diamond-like carbon (H-DLC) films; these processes were not observed in the irradiation of a low-hydrogenated DLC film. The extent of decrease in hydrogen content due to SR exposure was found to decrease with increasing the etching ratio of the H-DLC film. This indicates that hydrogen desorption from the H-DLC films competed with the etching process. Namely, the modified surface, in which hydrogen content was decreased by SR exposure, was immediately removed from the H-DLC film that had a high etching rate. (C) 2011 The Japan Society of Applied Physics

  IOP PUBLISHING LTD, May 2011, JAPANESE JOURNAL OF APPLIED PHYSICS, 50(5) (5), English

  [Refereed]

  Scientific journal


• Fabrication of fluorine-terminated diamond-like carbon thin film using a hyperthermal atomic fluorine beam

  Kazuhiro Kanda, Noriko Yamada, Kumiko Yokota, Masahito Tagawa, Masahito Niibe, Makoto Okada, Yuichi Haruyama, Shinji Matsui

  Surface modification of diamond-like carbon (DLC) film was performed using a hyperthermal atomic fluorine beam on the purpose of production of hydrophobic surface by maintaining the high hardness of DLC film. By the irradiation of atomic fluorine beam of a 1.0 x 10(20) atoms/cm(2), the contact angle of a water drop against the DLC surface increased from 73 degrees to 111 degrees. The formation of CF3, CF2 and CF bonding on the modified DLC surface was confirmed from the measurements of X-ray photoelectron spectra and near-edge X-ray absorption fine structure spectra. Irradiation of hyperthermal atomic fluorine beam was concluded to produce insulator fluorine-terminated DLC film, which has high F content on the surface. by the taking of the use of neutral atomic beam as a fluorine source. (C) 2011 Published by Elsevier B.V.

  ELSEVIER SCIENCE SA, May 2011, DIAMOND AND RELATED MATERIALS, 20(5-6) (5-6), 703 - 706, English

  [Refereed]

  Scientific journal


• Local structural analysis of a-SiCx:H films formed by decomposition of tetramethylsilane in microwave discharge flow of Ar

  Akira Wada, Takeshi Ogaki, Masahito Niibe, Masahito Tagawa, Hidetoshi Saitoh, Kazuhiro Kanda, Haruhiko Ito

  Hydrogenated amorphous silicon carbide (a-SiCx:H) films were prepared by the decomposition of tetramethylsilane (TMS) with microwave discharge flow of Ar. When radio-frequency (RF) bias voltage (-V-RF) was applied to the substrate, the film hardness increased as (2.39 +/- 1.12)-(9.15 +/- 0.55) GPa for -V-RF = 0-100 V. The a-SiCx:H films prepared under various -V-RF conditions were analyzed by the carbon-K near edge X-ray absorption fine structure (NEXAFS), by the elastic recoil detection analysis (ERDA), and by the X-ray photoelectron spectroscopy (XPS). From a quantitative analysis of NEXAFS, the sp(2)/(sp(2)+sp(3)) ratios of C atoms were evaluated as 67.9 +/- 2.0, 55.4 +/- 2.7, and 51.7 +/- 0.7% for -V-RF = 0, 60, and 100 V. respectively. From ERDA, hydrogen content of the film prepared under the condition of - VRF = 100 V was found to decrease 28% comparing with that under -V-RF = 0 V. It is suggested that the cause of the increase of the film hardness when applying -V-RF is predominantly the growth of the sp(3)-hybridized structure of C atoms accompanied by the decrease of hydrogen terminations. (c) 2011 Elsevier B.V. All rights reserved.

  ELSEVIER SCIENCE SA, Mar. 2011, DIAMOND AND RELATED MATERIALS, 20(3) (3), 364 - 367, English

  [Refereed]

  Scientific journal


• Accuracy of Kapton-equivalent atomic oxygen fluence in a ground-based atomic oxygen experiments

  K. Yokota, M. Tagawa

  Erosion rates of pyromellitic-dianhydride oxydianiline (PMDA-ODA) polyimide by atomic oxygen (AO) exposure were measured in various conditions in order to study the validity of "Kapton-equivalent AO fluence". The laser-detonation AO beam facility at Kobe University was used for simulating the reaction of AO and PMDA-ODA polyimide. The mass change of PMDA-ODA polyimide was detected by a quartz crystal microbalance during AO exposures. The effects of sample temperature, angle of attack, synergistic effect with vacuum ultraviolet and collision energy on the erosion rate of PMDA-ODA were summarized. It was observed that the erosion rate of PMDA-ODA depends strongly on the exposure conditions of AO beam. It was become clear that the erosion rate of 3.0 × 10 -24 cm 3/atom for PMDA-ODA polyimide, which was measured in LEO, is not applicable in the ground-based experiments, if certain exposure conditions of AO beam in laboratory are different from that in LEO.

  2011, 62nd International Astronautical Congress 2011, IAC 2011, 7, 5829 - 5834, English

  International conference proceedings


• Role of hyperthermal atomic/molecular collisions on a space environmental effect of polymeric materials

  Masahito Tagawa, Kumiko Yokota

  Dec. 2010, Proc. Pacifichem 2010, CD-ROM, English

  [Refereed]

  International conference proceedings


• Near edge X-ray absorption fine structure measurements of DLC and a-SiCx:H films

  Akira Wada, Takeshi Ogaki, Tomoyuki Yasukawa, Fumio Mizutani, Masahito Tagawa, Tsuneo Suzuki, Masahito Niibe, Hidetoshi Saitoh, Kazuhiro Kanda, Haruhiko Ito

  Dec. 2010, 4th Workshop for International Standardization of Diamond-like Coatings, CD-ROM, English

  [Refereed]

  International conference proceedings


• Combined effect of atomic oxygen and vacuum ultraviolet on polymer degradation: Relevance to space environmental effect on polymer degradation

  Masahito Tagawa, Kumiko Yokota

  Dec. 2010, Proc. Pacifichem 2010, CD-ROM, English

  [Refereed]

  International conference proceedings


• Synchrotron radiation photoelectron spectroscopy and near-edge X-ray absorption fine structure study on oxidative etching of diamond-like carbon films by hyperthermal atomic oxygen

  Masahito Tagawaa, Kumiko Yokota, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka, Kazuhiro Kanda, Masahito Niibe

  Surface structural changes of a hydrogenated diamond-like carbon (DLC) film exposed to a hyperthermal atomic oxygen beam were investigated by Rutherford backscattering spectroscopy (RBS), synchrotron radiation photoelectron spectroscopy (SR-PES), and near-edge X-ray absorption. ne structure (NEXAFS). It was confirmed that the DLC surface was oxidized and etched by high-energy collisions of atomic oxygen. RBS and real-time mass-loss data showed a linear relationship between etching and atomic oxygen fluence. SR-PES data suggested that the oxide layer was restricted to the topmost surface of the DLC film. NEXAFS data were interpreted to mean that the sp(2) structure at the DLC surface was selectively etched by collisions with hyperthermal atomic oxygen, and an sp(3)-rich region remained at the topmost DLC surface. The formation of an sp(3)-rich layer at the DLC surface led to surface roughening and a reduced erosion yield relative to the pristine DLC surface. (C) 2010 Elsevier B.V. All rights reserved.

  ELSEVIER SCIENCE BV, Oct. 2010, APPLIED SURFACE SCIENCE, 256(24) (24), 7678 - 7683, English

  [Refereed]

  Scientific journal


• 原子状酸素に対する木質炭素／シリコン材料の抵抗性

  Takeshi Kajimoto, Toshimitu Hata, Masahito Tagawa, Hirotsugu Kojima, Yusuke Imamura, Hajime Hayakawa, Yoshikatsu Ueda, Hiroshi Yamakawa

  An analysis of the erosional properties of carbonized lignin with a Si content of 0 to 40% under the simulated atomic oxygen (AO) conditions found in low earth orbit was carried out. The AO environment was produced using a laser detonation atomic oxygen beam source. X-ray photoelectron spectroscopy revealed an increase in the atomic concentration of oxygen-related groups on the surface of the carbonized lignin with and without Si. The erosion rate was found to be low for the case of carbonized lignin with>20% Si. The Si-free sample exhibited a resistance to oxidation due to the formation of an oxide area that protected it from further AO effects on chemical bonds such as C=C bonds. The surface chemistry of the Si-free samples was similar to that of diamond-like carbon (DLC). These experimental results suggest that carbonized lignin derived from Sugi wood has the potential to be used in materials for space applications.

  High Temperature Society of Japan, Aug. 2010, 高温学会誌, Vol.36, No.4, pp.185-191(4) (4), 185 - 191, Japanese

  [Refereed]

  Scientific journal


• A Consideration of Future Flight Material Exposure Experiments in Japan: Advanced Material Exposure Test Working Group’s Proposal

  Masahito Tagawa, Kumiko Yokota, Mengu Cho, Minoru Iwata, Rikio Yokota, Mineo Suzuki, Koji Matsumoto, Yugo Kimoto, Eiji Miyazaki, Hiroyuki Shimamura

  In Japan, the largest material exposure program "SM/MPAC&SEED (Service Module/ Micro-Particles Capturer and Space Environment Exposure Device) Experiment" has been completed. This program is quite ambitious among the other Japanese materials exposure tests; 3 sets of samples have been exposed for 1, 2 and 3 years in orbit in order to discover the fluence dependence of the material responses. We have learned a lot of lessons from this program. Based on the lessons learned, the "Advanced Material Exposure Test Working Group" has been established by the Committee on Space Utilization in 2007. This working group discussed the current problems of the material exposure program (flight tests) and proposed the future direction of the experimental methodologies. In this presentation, problems and new challenges discussed in this working group will be discussed.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Aug. 2010, Transactions of the Japan Society for Aeronautical and Space Sciences, Space Technology Japan, Vol. 8,�No. ists27, pp.Th_1-Th(27) (27), Th_1 - Th_5, English

  [Refereed]

  Scientific journal


• Energy Dependence of Hyperthermal Oxygen Atom Erosion of a Fluorocarbon Polymer: Relevance to Space Environmental Effects

  Masahito Tagawa, Kumiko Yokota, Kazuhiro Kishida, Akio Okamoto, Timothy K. Minton

  The origin of the inconsistency in the erosion phenomena of fluorocarbon polymers between a ground-based atomic-oxygen test environment and the low Earth orbital space environment has been investigated. A detailed experiment was performed in order to study the effect of the high-energy component in the atomic-oxygen beam pulses on the erosion. The experiment was carried out with the combination of a polymer-coated quartz crystal microbalance and a high-speed chopper wheel installed in a laser-detonation atomic-oxygen facility. It was clearly observed that the mass-loss rates of both polyimide and fluorocarbon polymers depend on the impact energy of atomic oxygen. However, the energy dependence is more significant on the fluorocarbon polymer compared with that on polyimide. Collisions of atomic oxygen with translational energies higher than similar to 5 eV induce a significant mass loss on the fluorocarbon polymer. These experimental findings agree with earlier measurements of the volatile products released during hyperthermal O-atom bombardment, and they are consistent with theoretical calculations on related systems. It is concluded that the difference in the collision energy distribution of atomic oxygen between laboratory and space environments is the major reason for the difference in erosion yields measured in the two environments.

  AMER CHEMICAL SOC, Jul. 2010, ACS APPLIED MATERIALS & INTERFACES, 2(7) (7), 1866 - 1871, English

  [Refereed]

  Scientific journal


• Role of Inert Gas Collision on a Material Degradation in Low Earth Orbit

  Masahito Tagawa, Kumiko Yokota

  Jun. 2010, Proc. 61st International Astronautical Congress, CD-ROM, English

  [Refereed]

  International conference proceedings


• Degradation Property of Commercially Available Si-containing Polyimide in Simulated Atomic Oxygen Environments for Low Earth Orbit

  Kumiko Yokota, Shingo Abe, Masahito Tagawa, Minoru Iwata, Eiji Miyazaki, Jun-Ichiro Ishizawa, Yugo Kimoto, Rikio Yokota

  Real-time measurement of the erosion rate of a commercially available Si-containing polyimide (BSF30) under hyperthermal atomic oxygen (AO) beam exposure condition, which simulates the AO environment in low Earth orbit (LEO), was performed. It was found that the erosion rate of BSF30 decreased with increasing AO fluence and it reached as low as 4% of the standard PMDA-ODA polyimide. X-ray photoelectron spectroscopy confirmed that the surface of AO-exposed BSF30 was covered by a SiO(2) layer which functioned as a protective coating. In contrast, an SiO(2) surface layer thick enough to protect bulk BSF30 was not formed by thermal AO, which was generated by vacuum ultraviolet exposure in an O(2) atmosphere. Exposure to hyperthermal AO collision in LEO can also form an SiO(2) layer which enables the surface to be self-healing and is desirable for a polyimide that would be used in LEO.

  SAGE PUBLICATIONS LTD, Apr. 2010, HIGH PERFORMANCE POLYMERS, 22(2) (2), 237 - 251, English

  [Refereed]

  Scientific journal


• Evaluation and application of the EUV emitted from a laser-detonation atomic oxygen space environmental simulator: FY2009 report

  Masahito Tagawa, Kumiko Yokota, Hiroyuki Shimamura, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  Mar. 2010, 大阪大学レーザーエネルギー学研究センター平成21年度共同利用・共同研究成果報告会, pp184-185, English

  International conference proceedings


• Investigation into tolerance of polysiloxane-block-polyimide film against atomic oxygen

  Eiji Miyazaki, Masahito Tagawa, Kumiko Yokota, Rikio Yokota, Yugo Kimoto, Junichiro Ishizawa

  Silicon containing polyimide is proposed as an atomic-oxygen (AO)-tolerant material for Low Earth Orbit flight. For this study, commercially available polysiloxane-block-polyimide film is selected for investigation. An AO beam is irradiated on the polysiloxane-block-polyimide film at the Combined Space Effects Test Facility of JAXA in Tsukuba, Japan. To investigate the AO tolerance, mass change measurement, cross-sectional transmission electron microscopic (TEM) observation, and X-ray photoelectron spectroscopic (XPS) analysis are performed. Results show that the mass loss of polysiloxane-block-polyimide is one one-hundredth or less than that of Kapton (R) H: Cross-sectional TEM observation and XPS analysis reveals that the AO protective SiO(2) layer is self-organized by AO irradiation. Furthermore, the self-organized SiO(2) layer is intentionally damaged to investigate reorganization of a new layer on it. Further AO irradiation of the damaged surface revealed that the new layer is built with a 500-nm-deep eroded region. The result verifies the "self-healing" ability of polysiloxane-block-polyimide. These results suggest that polysiloxane-block-polyimide film has high potential to provide many advantages of a space-use material, especially for LEO spacecraft. (C) 2009 Elsevier Ltd. All rights reserved.

  PERGAMON-ELSEVIER SCIENCE LTD, Mar. 2010, ACTA ASTRONAUTICA, 66(5-6) (5-6), 922 - 928, English

  [Refereed]

  Scientific journal


• Effect of Vacuum Ultraviolet Exposure and Surface Oxide Layer on the Hydrogen Desorption from Hydrogenated Diamond-like Carbon Films

  Masahito Tagawa, Kumiko Yokota, Yuichi Furuyama, Kazuhiro Kanda, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  Feb. 2010, 第5回JEAE放射光科学シンポジウム, CD-ROM, English

  International conference proceedings


• Effect of ultraviolet emission from the oxygen plasma on the accelerated erosion phenomenon of fluorinated polymer in the atomic oxygen ground tests

  Masahito Tagawa, Kumiko Yokota, Kazuhiro Kishida, Akio Okamoto, Junichiro Ishizawa, Timothy K. Minto

  Feb. 2010, High Performance Polymers, Vol.22 No.2, pp.213-224., English

  [Refereed]

  Scientific journal


• Departure Process of Hydrogen from Highly-Hydrogenated Diamond-Like Carbon Film by Exposure to Synchrotron Radiation

  Kazuhiro Kanda, Kumiko Yokota, Masahito Tagawa, Mayumi Tode, Yuden Teraoka, Shinji Matsui

  Feb. 2010, 第5回JEAE放射光科学シンポジウム, CD-ROM, English

  International conference proceedings


• 原子状酸素地上試験の高精度化について

  Kumiko Yokota, Kazuhiro Kishida, Masahito Tagawa

  Jan. 2010, 第26回宇宙利用シンポジウム, pp.110-111, Japanese

  International conference proceedings


• 衛星搭載用原子状酸素センサーのキャリブレーション法について

  Masahito Tagawa, Kazuhiro Kishida, Kumiko Yokota

  Jan. 2010, 第26回宇宙利用シンポジウム, pp.112-113, Japanese

  International conference proceedings


• 衛星搭載用原子状酸素モニター装置の地上キャリブレーションに関する一考察

  Masahito Tagawa, Kumiko Yokota

  Oct. 2009, 第6回宇宙環境シンポジウム報告書, pp.179-182, Japanese

  International conference proceedings


• Tolerance of Commercially Available Polysiloxane-Block-Polyimide Film against Space Environment in Low Earth Orbit

  Eiji Miyazaki, Masahito Tagawa, Kumiko Yokota, Rikio Yokota, Yugo Kimoto, Junichiro Ishizawa

  Sep. 2009, Proceedings of the 11th International Symposium on Materials in Space Environment, CD-ROM, English

  International conference proceedings


• The remarkable lack of synergistic effects in the erosion of FEP teflon

  Timothy K. Minton, Jianming Zhang, Ned F. Lindholm, Amy L. Brunsvold, Hari P. Upadhyaya, Masahito Tagawa

  Sep. 2009, Proceedings of the 11th International Symposium on Materials in Space Environment, CD-ROM, English

  International conference proceedings


• Origins of the accelerated erosion of fluorinated polymer in a laser-detonation ground-based atomic oxygen facility

  Masahito Tagawa, Kumiko Yokota, Kazuhiro Kishida, Akio Okamoto

  Sep. 2009, Proceedings of the 11th International Symposium on Materials in Space Environment, CD-ROM, English

  International conference proceedings


• Durability of a Silicon-Containing Polyimide in a Simulated Low Earth Orbit Space Environment

  Kumiko Yokota, Masahito Tagawa, Minoru Iwata, Eiji Miyazaki, Jun-ichiro Ishizawa, Mineo Suzuki, Rikio Yokota

  Sep. 2009, Polyimides and Other High Temperature Polymers, Vol.5, pp379-390, English

  [Refereed]

  Scientific journal


• Combined effect of atomic oxygen and vacuum ultraviolet from deuterium lamp on the erosion of polymeric materials

  Kumiko Yokota, Kazuhiro Kishid, Akio Okamoto, Masahito Tagawa

  Sep. 2009, Proceedings of the 11th International Symposium on Materials in Space Environment, CD-ROM, English

  International conference proceedings


• Si-doping for the of hydrogenated diamond-like carbon films in a simulated atomic oxygen environment in LEO protection

  Kumiko Yokota, Masahito Tagawa, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka, Julien Fontaine, Michel Belin

  The effect of hyperthermal atomic oxygen (AO) exposure on a surface property of Si-doped DLC was investigated. Two types of DLC were tested which contain Si atoms approximately 10 at% and 20 at%. Surface analytical results of high-resolution x-ray photoelectron spectroscopy using synchrotron radiation (synchrotron radiation photoemission spectroscopy; SR-PES) as well as Rutherford backscattering spectroscopy (RBS) have been used for characterization of the AO-exposed Si-doped DLC. It was identified by SR-PES that the SiO₂ layer was formed by the hyperthermal AO exposure at the Si-doped DLC surface. RBS data indicates that AO exposure leads to severe thickness loss on the non-dope DLC, in contrast, SiO₂ layer formed by the hyperthermal atomic oxygen reaction at the Si-doped DLC protects the DLC underneath the SiO₂ layer.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2009, Space Technology Japan, Vol.7, pp.Pc_37-Pc_42.(26) (26), Pc_37 - Pc_42, English

  [Refereed]

  Scientific journal


• Issues and consequences of space environmental effect on materials

  Masahito Tagawa, Kumiko Yokota

  The importance of space environmental effect on material is addressed. Some examples of the material degradation in a particular space environment are introduced. In order to endorse the material properties requested in a mission, ground-based studies are quite important. However, present deficient ground-based simulation technology cannot perform the accurate assessment of the material degradation in space. On the other hand, infrastructures for the material evaluation using Kibo and International Space Station, is now established after long desire of material scientists and engineers. However, we will face difficulty for retrieve the exposed sample by the retirement of Space Shuttle. Development of new material evaluation methods using small satellite without retrieving the samples and of the accurate ground-based simulation techniques are both highly desired to achieve low-risk missions.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2009, Space Technology Japan, Vol.7, pp.Tr_2_21-Tr_2_26(26) (26), Tr_2_21 - Tr_2_26, English

  [Refereed]

  Scientific journal


• Erosion properties of PMDA-ODA polyimide as a reference material for atomic oxygen fluence monitoring

  Kumiko Yokota, Masahito Tagawa

  Jun. 2009, Proceedings of the 27th International Symposium on Space Technology and Science, USB Memory, English

  International conference proceedings


• Energy dependence on fluorinated polymer erosion by hyperthermal atomic oxygen exposures: a high-speed chopper and quartz crystal microbalance study

  Kazuhiro Kishida, Kumiko Yokota, Akio Okamoto, Masahito Tagawa

  Jun. 2009, Proceedings of the 27th International Symposium on Space Technology and Science, USB Memory, English

  International conference proceedings


• Effects of long-term irradiation with LEO environment effective factors on properties of solid lubricant

  Koji Matsumoto, Masahito Tagawa, Masao Akiyama

  This study evaluated effects of a low earth orbit (LEO) space environment on properties of a solid lubricant used for space applications. The tested lubricant was a bonded MoS₂ film with organic binder. The film was exposed to a real LEO space environment aboard the International Space Station (ISS) by the Space Environment Exposure Device (SEED) experiment for about 1400 days. Additionally, it was irradiated individually with atomic oxygen (AO), ultraviolet rays (UV), and electron beam (EB) on the ground. Fluences of these factors corresponded to exposure to the LEO environment by the SEED experiment. Friction tests in vacuum and surface analyses were carried out for the samples. Tribological behavior of the different samples was measured using classical reciprocating pin-on-flat friction tests. Furthermore, XPS analysis was performed for the film surface and rubbing tracks of the samples. Results show that the friction coefficient decreased by AO irradiation at an early stage of the tests. It resembled the result of the film exposed to the real LEO environment.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2009, Space Technology Japan, Vol.7, pp.Pc_31-Pc_36(26) (26), Pc_31 - Pc_36, English

  [Refereed]

  Scientific journal


• Atomic Layer Fluorination of Highly Oriented Pyrolytic Graphite using Hyperthermal Atomic Fluorine Beam

  Masahito Tagawa, Kumiko Yokota, Ken-ichi Maeda, Akitaka Yoshigoe, Yuden Teraoka

  Hyperthermal (kinetic energy of 10eV) fluorine atom beam interaction with highly oriented pyrolytic graphite (HOPG) was studied. Surface analytical results of atomic fluorine-exposed HOPG using synchrotron radiation photoelectron spectroscopy showed that the fluorine reaction was limited at the topmost HOPG(0001) layer. This is due to the fact that the kinetic energy of 10eV is not sufficient to penetrate graphite layer but is enough for breaking C-C bonds and forms CF and CF(2) functional groups through the beam-induced fluorination reactions. It was demonstrated that the use of hyperthermal energy in the range of 10eV is advantageous for damage-free modification of the topmost surface of carbon-based materials. (c) 2009 The Japan Society of Applied Physics

  JAPAN SOCIETY APPLIED PHYSICS, Jun. 2009, APPLIED PHYSICS EXPRESS, 2(6) (6), English

  [Refereed]

  Scientific journal


• An experimental study on air breathing ion engine using a laser-detonation atomic oxygen beam source as LEO space environment simulator

  Masahito Tagawa, Kazutaka Nishiyama, Kumiko Yokota, Yasuo Yoshizawa, Daisaku Yamamoto, Hitoshi Kuninaka

  Jun. 2009, Proceedings of the 27th International Symposium on Space Technology and Science, USB Memory, English

  International conference proceedings


• A consideration of future flight material exposure experiments in Japan: Advanced material exposure test working group’s proposal

  Masahito Tagawa, Kumiko Yokota, Mengu Cho, Minoru Iwata, Rikio Yokota, Mineo Suzuki, Koji Matsumoto, Yugo Kimoto, Eiji Miyazaki, Hiroyuki Shimamura

  In Japan, the largest material exposure program "SM/MPAC&SEED (Service Module/ Micro-Particles Capturer and Space Environment Exposure Device) Experiment" has been completed. This program is quite ambitious among the other Japanese materials exposure tests; 3 sets of samples have been exposed for 1, 2 and 3 years in orbit in order to discover the fluence dependence of the material responses. We have learned a lot of lessons from this program. Based on the lessons learned, the "Advanced Material Exposure Test Working Group" has been established by the Committee on Space Utilization in 2007. This working group discussed the current problems of the material exposure program (flight tests) and proposed the future direction of the experimental methodologies. In this presentation, problems and new challenges discussed in this working group will be discussed.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2009, Proceedings of the 27th International Symposium on Space Technology and Science, USB Memory(27) (27), Th_1 - Th_5, English

  International conference proceedings


• Photoemission Study of Hydrogenated Amorphous Carbon Thin Films as a Function of Annealing Temperature

  Yuichi Haruyama, Masahito Tagawa, Kumiko Yokota, Shinji Matsui

  The electronic structure in hydrogenated amorphous carbon (a-C:H) thin films as a function of annealing temperature was investigated by photoemission spectroscopy. The photoemission results of the valence band and the C 1s core level suggested that the graphitization of a-C:H films proceeds by annealing at more than 400 degrees C. From the photoemission spectra of the C 1s core level, the coordination of C atoms in a-C:H films was evaluated as a function of annealing temperature. On the basis of the evaluations, the electronic structure of a-C:H films as a function of annealing temperature is discussed. (C) 2009 The Japan Society of Applied Physics

  IOP PUBLISHING LTD, May 2009, JAPANESE JOURNAL OF APPLIED PHYSICS, 48(5) (5), English

  [Refereed]

  Scientific journal


• 生体材料への細胞接着・増殖性におよぼす原子ビーム表面改質効果

  Kumiko Yokota, Chiaki Hiwa, Masahito Tagawa, Yoshikazu Nakai, Taiji Adachi

  May 2009, 電気学会研究会、量子・光デバイス研究会, pp.51-54., Japanese

  International conference proceedings


• Electronic structure of hydrogenated amorphous carbon thin films as a function of annealing temperature using photoemission spectroscopy

  Yuichi Haruyama, Masahito Tagawa, Kumiko Yokota, Shinji Matsui

  May 2009, Japanese Journal of Applied Physics, Vol.48, 055505, English

  [Refereed]

  Scientific journal


• Evaluation and application of the EUV emitted from a laser-detonation atomic oxygen space environmental simulator

  Masahito Tagawa, Kumiko Yokota, Mayuko Koga, Hiroaki Nishimura

  Apr. 2009, レーザーエネルギー学研究センター 平成20年度共同利用・共同研究成果報告書, pp177-178., English

  International conference proceedings


• Hydrogen desorption from a diamond-like carbon film by hyperthermal atomic oxygen exposure

  Kumiko Yokota, Masahito Tagawa, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka

  The densities of hydrogen and carbon atoms in a hydrogenated diamond-like carbon (DLC) film exposed to a hyperthermal atomic oxygen beam were investigated by Rutherford backscattering spectroscopy (RBS) and elastic recoil detection analysis (ERDA). The hydrogen density in DLC decreased upon atomic oxygen beam exposure with collision energy as low as 2 eV, whereas an exposure greater than 3 eV was necessary to remove carbon atoms. A high-collision energy also led to hydrogen desorption in the deeper region of DLC. The surface density of hydrogen decreased 6% by atomic oxygen exposure, and was independent of the collision energy. Additionally, the non-bonded hydrogen, which could diffuse in DLC, was desorbed by the energy transfer from the atomic oxygen collisions. (C) 2009 Elsevier B. V. All rights reserved.

  ELSEVIER SCIENCE BV, Apr. 2009, APPLIED SURFACE SCIENCE, 255(13-14) (13-14), 6710 - 6714, English

  [Refereed]

  Scientific journal


• Erosion of FEP Teflon and PMMA by VUV Radiation and Hyperthermal O or Ar Atoms

  Jianming Zhang, Ned F. Lindholm, Amy L. Brunsvold, Hari P. Upadhyaya, Timothy K. Minton, Masahito Tagawa

  A combination of beam-surface-scattering, quartz-crystal-microbalance, and surface-recession experiments was conducted to study the effects of various combinations of O atoms [in the O((3)P) ground state], Ar atoms, and vacuum ultraviolet (VUV) light on fluorinated ethylene-propylene copolymer (FEP) Tenon and poly(methyl methacrylate) (PMMA). A laser-breakdown source was used to create hyperthermal beams containing O and O(2) or Ar. A D(2) lamp provided a source of VUV light. O atoms with 4 eV of translational energy or less did not react with a pristine FEP Tenon surface. Volatile O-containing reaction products were observed when the O-atom energy was higher than 4.5 eV, and the signal increased with the O-atom energy. Significant erosion of FEP Teflon (similar to 20 % of Kapton H) was observed when it was exposed to the hyperthermal O/O(2) beam with an average O-atom energy of 5.4 ev. FEP Teflon and PMMA that were exposed to VUV light alone exhibited much less mass loss. Collision-induced dissociation by hyperthermal Ar atoms also caused mass loss, similar in magnitude to that caused by VUV light. There were no observed synergistic effects when VUV light or Ar bombardment was combined with O/O(2) exposure. For both FEP Tenon and PMMA, the erosion yields caused by simultaneous exposure to O/O(2) and either VUV light or Ar atoms could be approximately predicted by adding the erosion yield caused by O/O(2), acting individually, to the erosion yield caused by the individual action of either VUV light or Ar atoms.

  AMER CHEMICAL SOC, Mar. 2009, ACS APPLIED MATERIALS & INTERFACES, 1(3) (3), 653 - 660, English

  [Refereed]

  Scientific journal


• Atomic Oxygen Concentrators for Material Exposure Acceleration Tests in Low Earth Orbit

  Masahito Tagawa, Hiroaki Doi, Kumiko Yokota

  Atomic oxygen concentration technology was investigated with two types of concentrators. One is a "horn-type" and the other is a "multiple ring-type" concentrator. Both of them were designed with a computer simulation using a hard-cube model. It was made clear that the primary factor for limiting the concentration factor is the gas buildup near the focal point. In the ground test using a laser-detonation source, which gave an intense atomic oxygen beam pulse, the concentration factor of 2-3, which is lower than the theoretical expectations, is obtained. However, it is suggested that the low concentration factor is due to the recombination reaction of atomic oxygen into molecular oxygen by the high peak flux in the pulsed atomic oxygen beam. The flux limit of the concentration factor is not a case in the real low Earth orbit space environment, and the multiple ring-type concentrator can be expected to achieve a concentration factor of over 40 in low Earth orbit exposure condition.

  AMER INST AERONAUT ASTRONAUT, Mar. 2009, JOURNAL OF SPACECRAFT AND ROCKETS, 46(2) (2), 226 - 229, English

  [Refereed]

  Scientific journal


• Synergistic effect of EUV from the laser-sustained detonation plasma in a ground-based atomic oxygen simulation on fluorinated polymers

  Masahito Tagawa, Shingo Abe, Kazuhiro Kishida, Kumiko Yokota, Akio Okamoto

  The contribution of extreme ultraviolet (EUV) from a laser-sustained plasma on the mass loss phenomenon of fluorinated polymer in a ground-based laser-detonation atomic oxygen beam source was evaluated. The atomic oxygen beam and EUV from the oxygen plasma were separated by the high-speed chopper wheel installed in the beam source. The mass changes of the fluorinated polymer and polyimide were measured from the frequency shift of the quartz crystal microbalance during the beam exposures. It has been made clear that the fluorinated polymer erodes by EUV exposure alone. In contrast, no erosion was detected for polyimide by EUV alone. The atomic oxygen-induced erosion was measured for both materials even without EUV exposure. However, no strong synergistic effect was observed for a fluorinated polymer even under the simultaneous exposure condition of atomic oxygen and EUV Similar results were observed even in simultaneous exposure of atomic oxygen (without EUV) and 172 nm vacuum ultraviolet (VUV) from an excimer lamp. These experiments suggest that the primary origin of the accelerated erosion of fluorinated polymer observed in a laser detonation atomic oxygen source is not the EUV from the laser-sustained plasma.

  AMER INST PHYSICS, 2009, PROTECTION OF MATERIALS AND STRUCTURES FROM SPACE ENVIRONMENT, 1087, 170 - +, English

  [Refereed]

  International conference proceedings


• Durability of Si-Containing Polyimide in a Simulated Atomic Oxygen Environment for Low Earth Orbit Applications

  Kumiko Yokota, Masahito Tagawa, Minoru Iwata, Eiji Miyazaki, Jun-ichiro Ishizawa, Mineo Suzuki, Rikio Yokota

  Real-time measurement of the erosion rate of a commercially available Si-containing polyimide (BSF30#1) on hyperthermal atomic oxygen (AO) beam exposure, which simulates the AO environment in low Earth orbit (LEO), was performed. It was found that the erosion rate of BSF30#1 decreased with increasing AO fluence and it reached as low as 4% of the conventional PMDA-ODA polyimide. X-ray photoelectron spectroscopic analysis confirmed that the surface of AO-exposed BSF30#1 was covered by SiO2 layer which functioned as a protective coating. The self-healing capability of this material is desirable for a space-applicable polyimide.

  E J BRILL, 2009, POLYIMIDES AND OTHER HIGH-TEMPERATURE POLYMERS: SYNTHESIS, CHARACTERIZATION AND APPLICATIONS, VOL 5, 379 - 389, English

  [Refereed]

  International conference proceedings


• Tribological characteristics of bonded MoS2 film exposed to AO, UV and real LEO environment in SM/SEED experiment

  Koji Matsumoto, Masahito Tagawa, Masao Akiyama

  Influence of a ground-simulated space environment on a solid lubricant was compared to that of the real space environment. The tested lubricant that has been used for space applications was a bonded MoS2 film with organic binder The film was irradiated individually with atomic oxygen (AO), ultraviolet rays (UV), and election beam (EB). The fluencies of these space environment factors corresponded to exposure to the LEO environment around the International Space Station (ISS) in the Space Environment Exposure Device (SEED) experiment to about 1, 2, and 3 years. Friction tests in vacuum and surface analyses were carried out for the samples. Tribological behavior of die different samples was measured using a classical reciprocating pin-on-flat friction test. Furthermore, XPS analysis of the film surface and the rubbing tracks was performed on the samples. Results show that due to AO irradiation, the friction coefficient decreased at an early stage of the tests that was similar to the results obtained on film exposed to the real LEO environment. However, no significant difference was observed with difference in AO fluence, whereas the friction coefficient of flight samples decreased concomitantly with die duration of exposure to the LEO environment.

  AMER INST PHYSICS, 2009, PROTECTION OF MATERIALS AND STRUCTURES FROM SPACE ENVIRONMENT, 1087, 148 - +, English

  [Refereed]

  International conference proceedings


• Role of High-Impact Energy of O-Atom on the Material Degradation in a LEO Space Environment

  Masahito Tagawa, Kumiko Yokota

  O-atom has been well known that it reacts with many space materials used in low Earth orbit and induces severe erosion. One of the important points of this phenomenon is the impact energy of O-atom with materials. Due to the high-orbital velocity of a spacecraft, the impinging energy of O-atom reaches as high as 5-6 electronvolts, which is similar (or higher) than the interatomic bonding energy. The chemical reactions occur at the spacecraft surfaces may strongly be influenced by this impinging energy. The effect of this impinging energy on the O-atom/surface reactions is discussed.

  AMER INST PHYSICS, 2009, RAREFIED GAS DYNAMICS, 1084, 688 - 693, English

  [Refereed]

  International conference proceedings


• Hyperthermal Atomic Beam Concentrators for Aerospace Applications

  Kumiko Yokota, Masahito Tagawa

  For the high-fluence atomic oxygen exposure tests, we have investigated atomic oxygen concentration technology. Based upon the previous results relating material selection or shape of the reflecting surface, two types of concentrators were designed. One is "horn-type" and the other is "multiple ring-type" concentrator. Both of them were designed with a computer simulation using the hard cube model. It was made clear that the primary factor for limiting the concentration factor is the gas build-up near the focal point. In the ground test using laser detonation source, the concentration factor of 2-3, which is lower than the theoretical expectations, was measured. It was suggested that the low concentration factor was due to the recombination reaction of atomic oxygen into molecular oxygen by the high peak flux in the pulsed atomic oxygen beam. The flux-limit of concentration factor is not a case in real low Earth orbit space environment, and the "multiple ring-type" concentrator can be expected to obtain the concentration factor over 40 in low Earth orbit exposure condition.

  AMER INST PHYSICS, 2009, RAREFIED GAS DYNAMICS, 1084, 606 - 612, English

  [Refereed]

  International conference proceedings


• 大気吸入型イオンエンジン(ABIE)に関する実験的研究

  Masahito Tagawa, Kazutaka Nishiyama, Kumiko Yokota, Yasuo Yoshizawa, Daisaku Yamamoto, Hitoshi Kuninaka

  Jan. 2009, 平成20年度宇宙輸送シンポジウム, CD-ROM, Japanese

  International conference proceedings


• 2008年度軌道上材料曝露実験高度化ワーキンググループ活動報告

  Masahito Tagawa, Kumiko Yokota, Mengu Cho, Minoru Iwata, Rikio Yokota, Mineo Suzuki, Koji Matsumoto, Yugo Kimoto, Hiroyuki Shimamura

  Jan. 2009, 第25回宇宙利用シンポジウム, pp.282-283, Japanese

  International conference proceedings


• Fluorination of PMDA-ODA Polyimide Using Hyperthermal Atomic Fluorine Beams

  Masahito Tagawa, Kumiko Yokota, Ken-ichi Maeda, Akitaka Yoshigoe, Yuden Teraoka, Kensuke Akamatsu, Hidemi Nawafune

  Hyperthermal fluorine atomic beam interaction with PMDA-ODA polyimide (PI)has been studied. It was found that CF, CF2 and CF3 groups were formed by reaction of PI with atomic fluorine with an impingement energy of 11.7 eV. Advancing contact angle of water increases rapidly to 100 degrees, followed by a slow increase due to the increase in surface roughness. A gasification reaction of PMDA-ODA was observed under hyperthermal atomic fluorine exposure, and the erosion yield was of the same order of magnitude as that by atomic oxygen. Surface analysis results of atomic fluorine-exposed highly oriented pyrolytic graphite `(HOPG) using synchrotron radiation photoelectron spectroscopy showed that the fluorine concentration was limited to only topmost HOPG (0 0 0 1) layer. From the HOPG experiment, it is revealed that the physical sputtering effect can be ignored in this hyperthermal atomic beam process and fluorination reaction was restricted only to the topmost graphite layer.

  E J BRILL, 2009, POLYIMIDES AND OTHER HIGH-TEMPERATURE POLYMERS: SYNTHESIS, CHARACTERIZATION AND APPLICATIONS, VOL 5, Vol.5, pp249-260, 249 - 259, English

  [Refereed]

  International conference proceedings


• Problems and Recent Trends on Material Degradation Studies in a Real and Simulated Space Environmen

  Masahito Tagawa, Kumiko Yokota

  Dec. 2008, 5th Space Environment Conference, Vol.5, 66, English

  [Refereed]

  International conference proceedings


• Selective etching of sp2 carbon in a diamond-like carbon film by hyperthermal atomic oxygen exposures

  Masahito Tagawa, Kumiko Yokota, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka, Kazuhiro Kanda, Masahito Niibe

  Oct. 2008, 4th Vacuum and Surface Sciences Conference of Asia and Australia, pp.263., English

  International conference proceedings


• Change in hydrogen amount in a diamond-like carbon film under hyperthermal atomic oxygen exposures

  Kumiko Yokota, Masahito Tagawa, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka

  Oct. 2008, 4th Vacuum and Surface Sciences Conference of Asia and Australia, pp.264., English

  International conference proceedings


• ERDA/RBS/SR-PES study on the effect of reactive atomic beam exposures to the hydrogenated diamond-like carbon films

  Masahito Tagawa, Kumiko Yokota, Akira Kitamura, Akitaka Yoshigoe, Yuden Teraoka

  Aug. 2008, 4th International Workshop on Reactions involving Oxidation & Hydrogen, 30-41, English

  International conference proceedings


• Si-doping for the protection of hydrogenated diamond-like carbon films in a simulated atomic oxygen environment in LEO

  Kumiko Yokota, Masahito Tagawa, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka, Julien Fontaine, Michel Belin

  The effect of hyperthermal atomic oxygen (AO) exposure on a surface property of Si-doped DLC was investigated. Two types of DLC were tested which contain Si atoms approximately 10 at% and 20 at%. Surface analytical results of high-resolution x-ray photoelectron spectroscopy using synchrotron radiation (synchrotron radiation photoemission spectroscopy; SR-PES) as well as Rutherford backscattering spectroscopy (RBS) have been used for characterization of the AO-exposed Si-doped DLC. It was identified by SR-PES that the SiO₂ layer was formed by the hyperthermal AO exposure at the Si-doped DLC surface. RBS data indicates that AO exposure leads to severe thickness loss on the non-dope DLC, in contrast, SiO₂ layer formed by the hyperthermal atomic oxygen reaction at the Si-doped DLC protects the DLC underneath the SiO₂ layer.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2008, Proceedings of the 26th International Symposium on Space Technology and Sciences, CD-ROM(26) (26), Pc_37 - Pc_42, English

  International conference proceedings


• Issues and consequences of space environmental effect on materials

  Masahito Tagawa, Kumiko Yokota

  The importance of space environmental effect on material is addressed. Some examples of the material degradation in a particular space environment are introduced. In order to endorse the material properties requested in a mission, ground-based studies are quite important. However, present deficient ground-based simulation technology cannot perform the accurate assessment of the material degradation in space. On the other hand, infrastructures for the material evaluation using Kibo and International Space Station, is now established after long desire of material scientists and engineers. However, we will face difficulty for retrieve the exposed sample by the retirement of Space Shuttle. Development of new material evaluation methods using small satellite without retrieving the samples and of the accurate ground-based simulation techniques are both highly desired to achieve low-risk missions.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2008, Proceedings of the 26th International Symposium on Space Technology and Sciences, CD-ROM(26) (26), Tr_2_21 - Tr_2_26, English

  International conference proceedings


• Effect of long-term irradiation with effective factors of LEO environment on properties of solid lubricant

  Koji Matsumoto, Masahito Tagawa, Masao Akiyama

  This study evaluated effects of a low earth orbit (LEO) space environment on properties of a solid lubricant used for space applications. The tested lubricant was a bonded MoS₂ film with organic binder. The film was exposed to a real LEO space environment aboard the International Space Station (ISS) by the Space Environment Exposure Device (SEED) experiment for about 1400 days. Additionally, it was irradiated individually with atomic oxygen (AO), ultraviolet rays (UV), and electron beam (EB) on the ground. Fluences of these factors corresponded to exposure to the LEO environment by the SEED experiment. Friction tests in vacuum and surface analyses were carried out for the samples. Tribological behavior of the different samples was measured using classical reciprocating pin-on-flat friction tests. Furthermore, XPS analysis was performed for the film surface and rubbing tracks of the samples. Results show that the friction coefficient decreased by AO irradiation at an early stage of the tests. It resembled the result of the film exposed to the real LEO environment.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2008, Proceedings of the 26th International Symposium on Space Technology and Sciences, CD-ROM(26) (26), Pc_31 - Pc_36, English

  International conference proceedings


• Effect of EUV from the oxygen plasma in the ground-based atomic oxygen test of fluorinated polymer

  Masahito Tagawa, Shingo Abe, Kazuhiro Kishida, Kumiko Yokota, Akio Okamoto

  Jun. 2008, Proceedings of the 26th International Symposium on Space Technology and Sciences, CD-ROM, English

  International conference proceedings


• Synergistic effect of EUV from the laser-sustained oxygen plasma in the ground-based atomic oxygen simulation of fluorinated polymers

  Masahito Tagawa, Shingo Abe, Kazuhiro Kishida, Kumiko Yokota, Akio Okamoto

  May 2008, Proceedings of 9th International Space Conference, Protection of Materials and Structures from the LEO Space Environment, AIP Conference Proceedings 108, English

  [Refereed]

  International conference proceedings


• Protection of diamond-like carbon films from an energetic atomic oxygen bombardment with Si-doping technology

  Kumiko Yokota, Masahito Tagawa, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka, Julien Fontaine, Michel Belin

  May 2008, Proceedings of 9th International Space Conference, Protection of Materials and Structures from the LEO Space Environment, AIP Conference Proceedings 108, English

  [Refereed]

  International conference proceedings


• Future Space Exposure Experiment beyond 2011 -Its Problems and New Challenges

  Masahito Tagawa

  Mar. 2008, Proceedings of International Symposium on SM/MPAC-SEED Experiment, JAXA-SP-08-015E, pp.171-176., English

  International conference proceedings


• Evaluation of MoS2 Bonded Film Degradation on ISS SM-SEED Experiment

  Masao Akiyama, Masahito Tagawa, Koji Matsumoto

  Mar. 2008, Proceedings of International Symposium on SM/MPAC-SEED Experiment, JAXA-SP-08-015E, pp.127-130., English

  International conference proceedings


• 摩擦誘起極改質ダイヤモンドライクカーボン薄膜の放射光/超音速分子線による非破壊評価

  Masahito Tagawa, Kumiko Yokota, Akitaka Yoshigoe, Yuden Teraoka, Koji Matsumoto

  Feb. 2008, 第3回JEAE放射光科学シンポジウム, pp.289-300, Japanese

  International conference proceedings


• Investigation into tolerance of polysiloxane-block-polyimide film against atomic oxygen

  Eiji Miyazaki, Masahito Tagawa, Rikio Yokota, Yugo Kimoto, Junichiro Ishizawa

  Silicon containing polyimide is proposed as an atomic-oxygen (AO)-tolerant material for Low Earth Orbit flight. For this study, commercially available polysiloxane-block-polyimide film is selected for investigation. An AO beam is irradiated on the polysiloxane-block-polyimide film at the Combined Space Effects Test Facility of JAXA in Tsukuba, Japan. To investigate the AO tolerance, mass change measurement, cross-sectional transmission electron microscopic (TEM) observation, and X-ray photoelectron spectroscopic (XPS) analysis are performed. Results show that the mass loss of polysiloxane-block- polyimide is one one-hundredth or less than that of Kapton® H: Cross-sectional TEM observation and XPS analysis reveals that the AO protective SiO2 layer is self-organized by AO irradiation. Furthermore, the self-organized SiO2 layer is intentionally damaged to investigate reorganization of a new layer on it. Further AO irradiation of the damaged surface revealed that the new layer is built with a 500-nm-deep eroded region. The result verifies the "self-healing" ability of polysiloxane-block- polyimide. These results suggest that polysiloxane-block-polyimide film has high potential to provide many advantages of a space-use material, especially for LEO spacecraft.

  2008, International Astronautical Federation - 59th International Astronautical Congress 2008, IAC 2008, 9, 5637 - 5646, English

  International conference proceedings


• 低軌道宇宙環境下での材料曝露試験高度化のための原子状酸素収束化技術の開発

  Kumiko Yokota, Masahito Tagawa

  Jan. 2008, 第24回宇宙利用シンポジウム, pp.80-81, Japanese

  International conference proceedings


• 軌道上材料曝露実験高度化ワーキンググループ活動報告

  Masahito Tagawa, Kumiko Yokota, Mineo Suzuki, Eiji Miyazaki, Hiroyuki Shimamura, Rikio Yokota, Koji Matsumoto, Mengu Cho, Minoru Iwata

  Jan. 2008, 第24回宇宙利用シンポジウム, pp.78-79, Japanese

  International conference proceedings


• Erosion properties of polyimide as a monitoring material of atomic oxygen environment in space (3): Synergistic effect of atomic oxygen and ultraviolet

  Masahito Tagawa, Kumiko Yokota

  Jan. 2008, 第4回宇宙環境シンポジウム報告書, JAXA-SP-07-030, pp.121-124., English

  International conference proceedings


• Atomic oxygen-induced polymer degradation phenomena in simulated LEO space environments: How do polymers react in a complicated space environment?

  Masahito Tagawa, Kumiko Yokota

  Effect of relative intensity of atomic oxygen and vacuum ultraviolet (UV) in the synergistic effect of polyimide erosion was investigated. The relative intensity of atomic oxygen and UV was adjusted by rotating the polyimide sample at the crossover point of the beam axes of atomic oxygen and UV which crossed 90 degrees. The erosion rate of polyimide was measured by a quartz crystal microbalance. It was confirmed that the UV exposure at the atomic oxygen-exposed polyimide promoted the desorption of carbon oxides from the surface. In contrast, no mass change was detected when UV irradiated the polyimide surface without simultaneous atomic oxygen exposure. By changing the relative intensity of atomic oxygen and UV, increase in erosion rate up to 400% was observed when relative UV intensity is high. (c) 2007 Elsevier Ltd. All rights reserved.

  PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2008, ACTA ASTRONAUTICA, 62(2-3) (2-3), 203 - 211, English

  [Refereed]

  Scientific journal


• Changes in tribological characteristics of MoS2 bonded film by exposure to low earth orbit space environment

  Koji Matsumoto, Masao Akiyama, Masahito Tagawa

  Effects of a low earth orbit (LEO) space environment on tribological characteristics of a solid lubricant film were evaluated. The tested lubricant, which has been used for space applications, was a bonded molybdenum disulfide (MoS2) film with organic binder. Three sets of the specimen were exposed to a real LEO space environment for about 1, 2 and 3 years aboard the Service Module of the International Space Station (ISS) by the Space Environment Exposure Device (SEED) experiment. In this paper, results of friction tests in vacuum and surface analyses for the specimens exposed for 1 and 2 years are reported. The results are also compared to those of the specimens irradiated individually with atomic oxygen (AO), ultraviolet rays (UV) and electron beam (EB) on the ground.

  Vacuum Society of Japan, 2008, Journal of the Vacuum Society of Japan, 51(8) (8), 554 - 558, Japanese

  [Refereed]

  Scientific journal


• Space environmental effects on MoS(2) and diamond-like carbon lubricating films: Atomic oxygen-induced erosion and its effect on tribological properties

  M. Tagawa, K. Yokota, K. Matsumoto, M. Suzuki, Y. Teraoka, A. Kitamura, M. Belin, J. Fontaine, J-M. Martin

  Effect of 5 eV atomic oxygen beam exposure on the surface properties of sputter-deposited molybdenum disulfide (MoS(2)) and diamond-like carbon lubrication films is experimentally evaluated with relevance to space environmental effect in low Earth orbit. X-ray photoelectron spectra indicate that the loss of sulfur and oxidation of molybdenum at the atomic oxygen-exposed MoS(2) surface are significant. Depth profiles of sulfur and molybdenum indicate that the oxidation is restricted within 3 nm from the surface. This is due to the fact that Mo oxide plays as a protective layer against further atomic oxygen attack. The surface oxidation affects the friction coefficient, however it is recovered with sliding. Due to the delamination of oxide layer, wear-life of the film is reduced dramatically by certain exposure conditions. On the other hand, no severe oxidation states of carbon atoms are detected at DLC surface from the synchrotron radiation photoemission spectra. In contrast, loss of the DLC film itself is measured by Rutherford backscattering spectroscopy. These analytical results can be explained by the oxidative gasification of carbon atoms at DLC surface. (c) 2007 Elsevier B.V. All rights reserved.

  ELSEVIER SCIENCE SA, Dec. 2007, SURFACE & COATINGS TECHNOLOGY, 202(4-7) (4-7), 1003 - 1010, English

  [Refereed]

  Scientific journal


• Fluorination of PMDA-ODA Polyimide using Hyperthermal Atomic Fluorine Beams

  Tagawa Masahito, Yokota Kumiko, Maeda Kenichi, Yoshigoe Akitaka, Teraoka Yuden, Akamatsu Kensuke, Nawafune Hidemi

  Nov. 2007, 5th International Conference on Polyimides and Other High Temperature Polymers, pp. 43, English

  International conference proceedings


• Durability of a Silicon-Containing Polyimide in a Simulated Low Earth Orbit Space Environment

  Yokota Kumiko, Tagawa Masahito, Iwata Minoru, Miyazaki Eiji, Ishizawa Jun-ichiro, Suzuki Mineo, Yokota Rikio

  Nov. 2007, 5th International Conference on Polyimides and Other High Temperature Polymers, pp. 26, English

  International conference proceedings


• Atomic beam-induced fluorination of polyimide and its application to site-selective Cu metallization

  Masahito Tagawa, Ken-ichi Maeda, Tadashi Kajita, Kumiko Yokota, Kensuke Akamatsu, Hidemi Nawafune

  Metallization methods of polyimide by hyperthermal atomic oxygen and atomic fluorine beams were developed. An atomic fluorine beam with atranslational energy of 6.2 eV modified the wettability of polyimide surfaces to provide an advancing water contact angle of 132 degrees. It was confirmed that in-air storage for 2 months did not alter the hydrophobic property created by the atomic fluorine beam. This stable bearn-indUced surface fluorination technique was then applied to site-selective electroless Cu platingon polyimide. Itwas demonstrated thatchanging the exposure sequence could create both positive- and negative-type plating processes.

  AMER CHEMICAL SOC, Nov. 2007, LANGMUIR, 23(23) (23), 11351 - 11354, English

  [Refereed]

  Scientific journal


• 複合宇宙環境下における材料劣化現象とそのコンタミネーションソースとしての可能性

  YOKOTA Kumiko, TAGAWA Masahito

  Sep. 2007, 第1回コンタミネーション管理技術ワークショップ, pp. 51-61, Japanese

  International conference proceedings


• Performance alteration of MoS2 solid lubricant due to long exposure duration to LEO space environment aboard ISS

  Matsumoto Koji, Belin Michel, Fontaine Julien, Le Mogne Thierry, Suzuki Mineo, Tagawa Masahito

  Sep. 2007, 34th Leeds-Lyon Symposium, pp. 100, English

  International conference proceedings


• MoS2焼成膜

  AKIYAMA Masao, KISHI Katsuhiro, TAGAWA Masahito, MATSUMOTO Koji

  Aug. 2007, 国際宇宙ステーションロシアサービスモジュール利用微小粒子捕獲実験及び材料曝露実験回収試料評価結果第2回中間報告会, JAXA-SP-06-021, pp.35-36, Japanese

  International conference proceedings


• Direct insertion of oxygen atoms into the backbonds of subsurface Si atoms using translational energies of oxygen atom beams

  Masahito Tagawa, Kumiko Yokota, Shinnosuke Tsumamoto, Chie Sogo, Akitaka Yoshigoe, Yuden Teraoka

  A direct oxidation reaction of Si atoms on a Si(001) surface was studied by ellipsometry and synchrotron radiation photoemission spectroscopy. In situ ellipsometry measurements when exposed to 2.7-5.0 eV O atom beams indicated that oxide growth follows a linear relationship with an O atom fluence up to an oxide thickness of 0.6-0.7 nm. In contrast, the limit of linear growth was 0.3 nm in the case of the 1.8 eV beam. These results suggest that the backbonds of Si atoms in the first layer are directly oxidized by O atom with a translational energy between 2.7 and 5.0 eV. (C) 2007 American Institute of Physics.

  AMER INST PHYSICS, Jul. 2007, APPLIED PHYSICS LETTERS, 91(3) (3), English

  [Refereed]

  Scientific journal


• 二硫化モリブデン焼成膜の宇宙環境曝露による特性変化

  MATSUMOTO Koji, AKIYAMA Masao, TAGAWA Masahito

  Jun. 2007, 日本真空協会研究例会, pp. 25-29, Japanese

  International conference proceedings


• Potential hazards on the oxidation reaction of satellite materials in the extreme environments in spac

  Tagawa Masahito, Yokota Kumiko

  May 2007, 3rd International Workshop on Oxidation Reactions, pp. 33-45, English

  International conference proceedings


• 低軌道宇宙環境下での材料曝露試験高度化のための原子状酸素収束化技術の開発

  TAGAWA Mashito, YOKOTA Kumiko

  日本マイクログラビティ応用学会, Apr. 2007, 日本マイクログラビティ応用学会誌, Vol.24, No.2, pp. 188-193(2) (2), 188 - 193, Japanese

  [Refereed]

  Scientific journal


• Low Earth Orbit Space Environmental Effects on MoS2/DLC Lubrication Films

  Tagawa Masahito, Yokota Kumiko, Matsumoto Koji, Belin Michel

  Apr. 2007, International Conference on Metallurgical coatings and thin films, 10, English

  International conference proceedings


• 低軌道宇宙環境下におけるダイヤモンドライクカーボンの表面損傷と膜内水素量変化について

  TAGAWA Masahito, YOKOTA Kumiko, KITAMURA Akira, YOSHIGOE Akitaka, TERAOKA Yuden

  Mar. 2007, 第2回JAEA放射光科学シンポジウム, pp.323-334, English

  International conference proceedings


• 低軌道宇宙環境下におけるダイヤモンドライクカーボンの表面損傷と膜内水素量変化について

  Masahito Tagawa, Kumiko Yokota, Akira Kitamura, Akitaka Yoshigoe, Yuden Teraoka

  Mar. 2007, 第2回JAEA放射光科学シンポジウム講演予稿集, 323-334, Japanese

  International conference proceedings


• SEED flight samples-

  Tagawa Masahito, Yokota Kumiko, Akiyama Masao, Matsumoto Koji, Suzuki Mineo

  Mar. 2007, Workshop on Micro- and Nano Engineering for Aerospace Systems, 157, English

  [Refereed]

  International conference proceedings


• Comparison of polyethylene and polyimide as a fluence monitor of atomic oxygen

  Kumiko Yokota, Masahito Tagawa

  Synergistic effect on atomic oxygen-induced erosion of polyethylene and polyimide with 172 nm monochromatic ultraviolet exposure was compared. The erosion of these materials was measured by a quartz crystal microbalance under 5 eV simultaneous atomic oxygen and ultraviolet exposures. The effect of simultaneous ultraviolet exposure on the atomic oxygen-induced erosion was observed at the ultraviolet intensity of 0.5-2.6 x 10(-15) mJ/atom for polyethylene. In contrast, the similar effect was observed in polyimide at the relative ultraviolet intensities one order greater than that of polyethylene. It was found that the effect of 172 nm ultraviolet was different in polyimide and polyethylene, i.e., photoinduced erosion was observed only for polyethylene. It was concluded that polyimide is less sensitive with simultaneous ultraviolet exposure during atomic oxygen bombardment, and thus evaluated as a better material for measuring atomic oxygen fluence.

  AMER INST AERONAUT ASTRONAUT, Mar. 2007, JOURNAL OF SPACECRAFT AND ROCKETS, 44(2) (2), 434 - 438, English

  [Refereed]

  Scientific journal


• Development of Atomic Oxygen Concentration Technology for Advanced Material Exposure Tests in Low Earth Orbit Space Environment

  Masahito Tagawa, Kumiko Yokota

  Atomic oxygen concentrator is developed in order to achieve acceleration tests of atomic oxygen exposures in low Earth orbit (LEO). A "multi ring-type" atomic oxygen concentrator is designed with a computer simulation using the Hard Cube Model. It is made clear that the theoretical concentration factor of atomic oxygen is expected to be 64, however the experimental value is restricted to be approximately 9. The primary factor for limiting the concentration factor is considered to be a gas build-up near the focal point. In the ground test using a laser detonation source like this study, which gives an intense atomic oxygen beam pulse within 30 mu s, the concentration factor is limited by the recombination reaction of atomic oxygen in the beam pulse. However, this is not a case in the real LEO space environment. It is expected that the "multiple ring-type" concentrator can be expected the concentration factor over 40 in LEO.

  JAPAN SOC MICROGRAVITY APPLICATION, 2007, INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION, 24(2) (2), 188 - 193, Japanese

  Scientific journal


• 第2回JAEA放射光科学シンポジウム講演予稿集

  Masahito Tagawa, Kumiko Yokota, Akira Kitamura, Akitaka Yoshigoe, Yuden Teraoka

  Jan. 2007, 低軌道宇宙環境下におけるダイヤモンドライクカーボンの表面損傷と膜内水素量変化について, 323, Japanese

  [Refereed]

  International conference proceedings


• Surface modification of a diamond-like carbon thin film using hyperthermal fluorine beams

  N. Yamada, K. Kanda, K. Yokota, M. Tagawa, M. Niibe, Y. Haruyama, S. Matsui

  Surface modification of a diamond-like carbon (DLC) thin film was performed using hyperthermal fluorine beams. After the irradiation of fluorine beam, the contact angle of a water drop against the DLC surface increased from 73 degrees to 87 degrees. The formation of C-F bonding was confirmed from the carbon K-edge near-edge X-ray absorption fine structure (NEXAFS) study on the DLC surface after irradiation of fluorine beam.

  JAPAN SOCIETY APPLIED PHYSICS, 2007, MICROPROCESSES AND NANOTECHNOLOGY 2007, DIGEST OF PAPERS, pp. 166-167, 166 - 167, English

  International conference proceedings


• Detailed structural analysis and dielectric properties of silicon nitride film fabricated using pure nitrogen plasma generated near atmospheric pressure

  Ryoma Hayakawa, Mari Nakae, Takeshi Yoshimura, Atsushi Ashida, Norifumi Fujimura, Tsuyoshi Uehara, Masatoshi Tagawa, Yuden Teraoka

  A detailed structural analysis and dielectric property measurements of silicon nitride films fabricated using atmospheric pressure (AP) plasma were carried out, and the results were compared to those of nitride films fabricated using a radio frequency plasma. Using AP plasma, 1.8-nm-thick silicon nitride films composed of Si(3)N(3.5)O(0.7) were obtained at nitridation temperatures ranging from 25 to 500 degrees C. X-ray photoelectron spectroscopy using a monochromatic Al K alpha source at 1486.6 eV and high-resolution Rutherford backscattering spectrometry revealed approximately 10% more nitrogen atoms corresponding to the N-Si(3) bond in the film using AP plasma than those using rf plasma. In the range of 25-500 degrees C, the nitridation temperature did not affect the leakage current densities of the films fabricated using AP plasma. Films fabricated at 25 degrees C showed leakage current density of as low as 7x10(-2) A/cm(2) at 5 MV/cm. This value was one order of magnitude lower than that using rf plasma. The direct-tunneling current simulation analysis with the Wentzel-Kramers-Brillouin approximation revealed that the effective tunneling mass of holes increased due to the nitrogen atoms incorporated in the films. From deep-level transient spectroscopy, signals attributed to defects generated by plasma irradiation in the silicon substrate were not observed. (c) 2006 American Institute of Physics.

  AMER INST PHYSICS, Oct. 2006, JOURNAL OF APPLIED PHYSICS, 100(7) (7), English

  [Refereed]

  Scientific journal


• PHYS 171-Synchrotron radiation photoemission spectroscopic study on the room temperature oxidation of Si(001):H formed by hyperthermal atomic/molecular beams

  Tagawa Masahito, Yokota Kumiko, Yoshigoe Akitaka, Teraoka Yuden

  Sep. 2006, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 232

  [Refereed]


• Synergistic effects of vacuum ultraviolet on the atomic oxygen-induced erosion of fluorinated polymer

  Kumiko Yokota, Kohei Ikeda, Masahito Tagawa, Akio Okamoto

  The synergistic effects of vacuum ultraviolet (VUV) on atomic oxygen (AO)-induced erosion of fluorinated ethylene propylene (FEP) film were quantitatively investigated through the ground-based experiments. The mass loss was detected even when FEP was exposed to AO or VUV individually. A sum of erosion rates by AO and by VUV alone matches that in simultaneous exposure conditions no synergistic effect was observed on FEP in the exposure conditions tested. No oxygen adsorption was detected even after AO exposures. These experimental results suggested that the FEP erosion by AO and that by VUV in the simultaneous exposure condition was provided through individual reaction channels.

  Sep. 2006, European Space Agency, (Special Publication) ESA SP, (616) (616), English

  International conference proceedings


• Atomic oxygen concentration for material exposure acceleration tests in low earth orbit

  Masahito Tagawa, Hiroaki Doi, Kumiko Yokota

  Atomic oxygen concentration technology was investigated with two types of concentrators. One is "horn-type" and the other is "multiple ring-type" concentrator. Both of them were designed with a computer simulation using hard cube model. It was made clear that the primary factor for limiting the concentration factor is the gas build-up near the focal point. In the ground test using laser detonation source, which gave intense atomic oxygen beam pulse, the concentration factor is limited by the recombination reaction. However, this is not a case in real low earth orbit space environment. The "multiple ring-type" concentrator can be expected the concentration ratio over 40 in low Earth orbit.

  Sep. 2006, European Space Agency, (Special Publication) ESA SP, (616) (616), English

  International conference proceedings


• A comparison of ultra-thin SiO2 films formed by hyperthermal O-atom beam and rapid thermal oxidation; synchrotron radiation photoemission and crystal truncation rod scattering study

  TAGAWA Masahito, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden, SHIMURA Takayoshi

  Sep. 2006, Applied Physics Letters, 88, 133512, English

  [Refereed]

  Scientific journal


• Computer simulation and its experimental verification of atomic oxygen concentration

  Masahito Tagawa, Koshi Matsumoto, Hiroaki Doi, Kumiko Yokota

  Feasibility of atomic oxygen concentration in low Earth orbit space environment for material testing was studied. To maximize the concentration efficiency, trajectories of the atomic oxygen reflected at the reflector surface were computer-simulated based on the Hard-Cube model, which can deal with inelastic scattering events at the solid surface. The difference in incident and exit angles was predicted to be at most 5 deg depending on the incident angle. The computational results were compared with the experimental results using a 5 eV hyperthermal atomic oxygen beam. A good correlation between the numerical and experimental, results was identified. It was experimentally demonstrated that the atomic oxygen flux could be increased six times greater than its original value with three reflective mirrors.

  AMER INST AERONAUT ASTRONAUT, Sep. 2006, JOURNAL OF SPACECRAFT AND ROCKETS, 43(5) (5), 999 - 1003, English

  [Refereed]

  Scientific journal


• Effect of surface charging on the erosion rate of polyimide under 5 eV atomic oxygen beam exposure

  Masahito Tagawa, Shinsuke Seikyu, Ken-Ichi Maeda, Kumiko Yokota, Nobuo Ohmae

  The effect of charging on the atomic oxygen-induced erosion of polyimide was investigated. A polyimide sample was spin-coated on the quartz crystal microbalance (QCM), and mass loss of the film was directly measured from the resonant frequency shift of QCM during atomic oxygen exposure. The experiment was carried out using the specially designed QCM, which allowed a sample bias voltage up to 1500 V during resonant frequency measurements. From the experimental results, we confirmed that the erosion rate of polyimide at +/- 1500 V was almost identical to that of grounded. It was, thus, concluded that the polyimide erosion by atomic oxygen is hardly affected by surface charging. A similar conclusion was also obtained with polysulfone. This conclusion was not consistent with that reported by King et al. [5]. The discrepancy of the experimental results could be due to the surface ionization yield of reaction products.

  KINOKUNIYA CO LTD, 2006, PROTECTION OF MATERIALS AND STRUCTURES FROM THE SPACE ENVIRONMENT, 6, 51 - +, English

  [Refereed]

  International conference proceedings


• Atomic oxygen concentration using reflecting mirrors

  Masahito Tagawa, Koshi Matsumoto, Hiroaki Doi, Kumiko Yokota, Nobuo Ohmae

  Feasibility of atomic oxygen concentration using reflecting mirrors was studied. Pyrex was selected as a material of reflecting surface due to its low recombination yield of atomic oxygen. Efficiency of reflection at Pyrex surface was measured to be 87.1 %. The focal point of atomic oxygen reflected by a concave mirror was predicted by a computer simulation based on Hard-Cube model. It was estimated from the computer-simulated results that the difference between incident and exit angles of atomic oxygen due to energy loss during inelastic scattering event was evaluated to be at most 5 degrees depending on the incident angle. The computational results on trajectories of atoms scattered at the Pyrex concave mirror were compared to experimental results, and good correlation was observed. A high-efficiency atomic oxygen concentrator is designed based on the experimental results reported herein.

  KINOKUNIYA CO LTD, 2006, PROTECTION OF MATERIALS AND STRUCTURES FROM THE SPACE ENVIRONMENT, 6, 417 - +, English

  [Refereed]

  International conference proceedings


• Enhancement of atomic oxygen-induced erosion of spacecraft polymeric materials by simultaneous ultraviolet exposure

  Kumiko Yokota, Nobuo Ohmae, Masahito Tagawa

  Synergistic effect on atomic oxygen-induced erosion of polyethylene and polyimide with 172 nm vacuum ultraviolet was investigated using a quartz crystal microbalance. In order to adjust the relative intensity of atomic oxygen and vacuum ultraviolet, the sample was rotated with an axis perpendicular both to the axes of atomic oxygen and ultraviolet. The erosion rate of polymers by ultraviolet exposure alone is independent of the incident angle of ultraviolet, whereas that by atomic oxygen alone follows cosine function. It was observed that the erosion rate of polyethylene increased 30-100% by a simultaneous exposure of 172 nm vacuum ultraviolet and 5 eV atomic oxygen depending on the relative intensity. The erosion of oxygen covered-polyethylene was three times greater than that of nonoxidized polyethylene. These erosion properties suggested that two independent erosion pathways exist in a simultaneous atomic oxygen and ultraviolet exposure condition; the atomic oxygen-induced erosion and the ultraviolet-induced erosion associated with oxidation.

  KINOKUNIYA CO LTD, 2006, PROTECTION OF MATERIALS AND STRUCTURES FROM THE SPACE ENVIRONMENT, 6, 141 - +, English

  [Refereed]

  International conference proceedings


• Synthesis of onion-like carbon and its microtribological properties

  J. Hiraki, 木之下 博, 田川 雅人, 大前 伸夫

  2006, Synopses of the International Tribology Conference Kobe (2005), E-01, English

  [Refereed]

  Scientific journal


• Synchrotron radiation photoelectron emission study of SiO2 film formed by hyperthermal O-atom beam at room temperature

  M Tagawa, C Sogo, K Yokota, S Hachiue, A Yoshigoe, Y Teraoka

  An ultrathin SiO2 overlayer on a Si(001) surface formed by a 5eV O-atom beam at room temperature was analyzed by synchrotron radiation photoelectron spectroscopy (SR-PES). SR-PES spectra clearly indicated that the SiO2 layer formed by a hyperthermal O-atom beam at room temperature contains a small amount of suboxides compared with that formed by high-temperature oxidation in O-2 atmosphere. Quantitative analysis suggests that the thickness of the structural transformation layer was less than a monolayer and the amount of suboxides was independent of the film thickness. The translational energy dependence of SR-PES spectra suggests that the reaction probability with a Si-atom increases with the translational energy of the O atoms in the range between 1 to 5 eV. The role of inverse diffusion of interstitial Si atoms in the kinetics of hyperthermal O-atom-beam oxidation is suggested.

  JAPAN SOC APPLIED PHYSICS, Dec. 2005, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 44(12) (12), 8300 - 8304, English

  [Refereed]

  Scientific journal


• Influence of humidity on microtribology of vertically aligned carbon nanotube film

  Turq, V, N Ohmae, JM Martin, J Fontaine, H Kinoshita, J Loubet

  The aim of this study is to probe the influence of water vapor environment on the microtribological properties of a forestlike vertically aligned carbon nanotube (VACNT) film, deposited on a silicon (001) substrate by chemical vapor deposition. Tribological experiments were performed using a gold tip under relative humidity varying from 0 to 100%. Very low adhesion forces and high friction coefficients of 0.6-1.3 resulted. The adhesion and friction forces were independent of humidity, due probably to the high hydrophobicity of VACNT. These tribological characteristics were compared to those of a diamond like carbon (DLC) sample.

  SPRINGER/PLENUM PUBLISHERS, May 2005, TRIBOLOGY LETTERS, 19(1) (1), 23 - 28, English

  [Refereed]

  Scientific journal


• Hyperthermal atomic oxygen interaction with MOS(2) lubricants and relevance to space environmental effects in low earth orbit - effects on friction coefficient and wear-life

  M Tagawa, M Muromoto, S Hachiue, K Yokota, N Ohmae, K Matsumoto, M Suzuki

  Wear-life of the MoS(2) film was evaluated by in situ tribological testing under 5 eV atomic oxygen exposures which simulated atomic oxygen environment in low Earth orbit. A combination of laser-detonation atomic oxygen source and a conventional pin-on-disk friction tester was used to perform tribological tests. It was confirmed that the friction coefficient was not affected by atomic oxygen exposure when atomic oxygen fluence was low; however, the friction coefficient increased with increasing atomic oxygen fluence and it reached as high as 0.05 at the atomic oxygen fluence of 3.4 X 10(16) atoms/cm(2)/cycle (nine times larger than the normal value). Effect of atomic oxygen on the wear-life of the film has much more drastic. With atomic oxygen fluence of 1.7 x 10(16) atoms/cm(2) cycle, wear-life was reduced less than one-tenth of that during ex situ testing result for the same film. It was also observed that wear-life of the film was inversely proportional to the atomic oxygen fluence between sliding passes.

  SPRINGER/PLENUM PUBLISHERS, Apr. 2005, TRIBOLOGY LETTERS, 18(4) (4), 437 - 443, English

  [Refereed]

  Scientific journal


• LPI法によるナノ形状セラミックスの高感度ガスセンサへの適用

  出来 成人, 水畑 穣, 梶並 昭彦, 大前 伸夫, 田川 雅人, 横田 久美子, 竹内 俊文, 石川 博, 蔡 奎千, 前川 享, 前田 浩一, 齋藤 靖弘, 関口 幸成, 小林 哲彦, 木内 正人, 桜井 宏昭, 山中 直樹, 山口 寿一

  Mar. 2005, 地域新生コンソーシアム研究開発事業 平成16年度報告書, 全24p, Japanese

  Scientific journal


• Polyimide erosion in a low Earth orbit space environment simulated by a laser detonation atomic oxygen beam facility

  Masahito Tagawa, Kumiko Yokota

  In low Earth orbit (LEO), 200-500 kin in altitude, highly reactive atomic oxygen, which is the dominant species in the upper atmosphere of the Earth, bombards the polyimide surface which is used as a passive thermal control material at the exterior of a spacecraft. Erosion of polyimide by atomic oxygen is very severe, so intensive research efforts have been carried out in the last decade. This paper provides an overview of the erosion properties of polyimide materials in an LEO space environment through ground-based simulation. The ground-based simulation technique and recent research results regarding hyperthermal atomic oxygen reaction with polyimide are described, including changes in surface composition due to air exposure, non-linear mass loss phenomenon, wettability, and impingement angle and sample temperature dependences on gasification reaction. The synergistic effects of atomic oxygen and ultraviolet exposures on polyimide erosion are also discussed.

  VSP BV-C/O BRILL ACAD PUBL, 2005, POLYIMIDES AND OTHER HIGH TEMPERATURE POLYMERS: SYNTHESIS, CHARACTERIZATION AND APPLICATIONS, VOL 3, 553 - 570, English

  [Refereed]

  International conference proceedings


• 表面帯電時における原子状酸素誘起高分子エロージョン

  YOKOTA kumiko, TAGAWA Masahito

  2005, 第1回宇宙環境シンポジウム報告書, JAXA-SP-04-010, pp.156-162, Japanese

  International conference proceedings


• 低地球軌道上の原子状酸素利用に向けての収束化技術の開発 (3)

  TAGAWA Masahito, YOKOTA Kumiko

  2005, 第21回宇宙利用シンポジウム講演予稿集, 2005, pp.168-169, Japanese

  International conference proceedings


• 低地球軌道上の原子状酸素によるシリコン酸化膜形成とその特徴 (2)

  TAGAWA Masahito, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden

  2005, 第21回宇宙利用シンポジウム講演予稿集, pp.166-16, Japanese

  International conference proceedings


• 宇宙用ポリイミドとフッ素系高分子における複合宇宙環境誘起劣化 -原子状酸素と紫外線の複合照射効果-

  YOKOTA kumiko, TAGAWA Masahito, IKEDA Kohei, OKAMOTO Akio

  A quantitative analysis in erosion properties of polyimide and fluorinated ethylene propylene (FEP) under simulated low earth orbit space environment of atomic oxygen and ultraviolet was performed. An atomic oxygen environment was simulated by a laser detonation atomic oxygen beam source, whereas that of ultraviolet was made by a 172 nm-eximer light. Increase in erosion rate up to 400 % was observed on polyimide when relative ultraviolet intensity is high. In contrast, no synergistic effect was observed on FEP in tested conditions. X-ray photoelectron spectroscopy revealed that atomic oxygen did not accommodate on FEP surfaces even after atomic oxygen exposures, in contrast, increase in surface oxygen concentration was detected at the polyimide surfaces. These experimental results suggest that ultraviolet-induced desorption of reactive products, which was an origin of synergistic effect on polyimide, does not occur at the FEP surface.

  High Temperature Society of Japan, 2005, 高温学会誌, Vol.31, No.5, 318-323(5) (5), 318 - 323, Japanese

  [Refereed]

  Scientific journal


• レーザーデトネーション誘起高速原子ビーム励起表面反応

  TAGAWA Masahito

  2005, 量子ビーム理工学研究最前線-その現状と今後の展望- 報告書, pp.170-180., Japanese

  International conference proceedings


• Surface degradation of polymeric materials under hyperthermal atomic oxygen beam bombardment; temperature dependence

  横田 久美子, Seikyu S, 大前 伸夫, 田川 雅人

  2005, International Symposium on Applications of Quantum Beam 2005, (2005) 221-222, English

  [Refereed]

  Scientific journal


• Surface degradation of polymeric materials under hyperthermal atomic oxygen beam bombardment; temperature dependenc

  YOKOTA Kumiko, SEIKYU Shinsuke, OHMAE Nobuo, TAGAWA Masahito

  2005, International Symposium on Applications of Quantum Beam 2005, pp.221-222, English

  International conference proceedings


• Surface and tribological properties of the MoS2 -based lubricants retrieved from real LEO space environment: The first and second year results obtained by SM/SEED

  M Akiyama, K Matsumoto, H Asada, K Ochi, K Yokota, M Tagawa

  Surface and tribological properties of molybdenum disulfide-based lubricants that were exposed to real low earth orbit space environment were analyzed. Organic binder-type MoS2 sample was exposed to space environment for one year and two years, and retrieved for analysis. Corresponding ground-based simulation tests were also carried out. XPS and EDS measurements suggested that electron beam and ultraviolet exposure did not affect chemical structure of MoS2 surfaces. However, atomic oxygen-exposed and flight samples showed surface oxidation. In addition, samples exposed to LEO environment were covered by silicon contamination. Friction coefficient of the flight sample was similar to that of the control sample.

  ESA PUBLICATIONS DIVISION C/O ESTEC, 2005, 11th European Space Mechanisms and Tribology Symposium, Proceedings, 591, 347 - 353, English

  International conference proceedings


• Photoemission spectroscopy with synchrotron radiation for nitrogen-impinged Si(001) surfaces with an ultra-thin-SiO2 overlaye

  HACHIUE Syunsuke, TERAOKA Yuden, TAGAWA Masahito

  2005, Proceedings of the 11th European Conference on Applications of Surface and Interface, in CD-ROM, English

  International conference proceedings


• Passive oxidation of Si(001) by hyperthermal atomic oxygen beam -A synchrotron radiation photoemission spectroscopic study

  TAGAWA Masahito, SOGO Chie, MIYAGAI Suguru, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden

  2005, International Symposium on Applications of Quantum Beam 2005, pp.223-224, English

  International conference proceedings


• Effect of Atomic Oxygen on The Mechanical and Surface Properties of Kevlar Fibers

  G. Lipika, N. Yokoi, 大前 伸夫, 横田 久美子, 田川 雅人

  2005, Synopses of the International Tribology Conference Kobe (2005), P-108, English

  [Refereed]

  Scientific journal


• Changes in Tribological Properties of MoS2 film exposed to LEO on SM/SEED

  MAATSUMOTO Koji, IMAGAWA Kichiro, AKIYAMA Masao, TAGAWA Masahito

  2005, Proceedings of World Tribology Congress-III, in CD-ROM, English

  International conference proceedings


• Atomic oxygen-induced polymer degradation phenomena in simulated LEO space environments: How do polymers react in a complicated space environment

  TAGAWA Masahito, YOKOTA Kumiko

  2005, Proceedings of the 56th International Astronautical Congress, in CD-ROM, English

  International conference proceedings


• Atomic oxygen-induced erosion of spacecraft materials -Potential hazards for spacecraft systems- (Plenary)

  TAGAWA Masahito

  2005, Proceedings of the 9th Spacecraft Charging Technology Conference, in CD-ROM, English

  International conference proceedings


• Atomic oxygen-induced erosion of polymeric materials under surface charging condition

  横田 久美子, 大前 伸夫, Seikyu S, 田川 雅人

  2005, Proceedings of the 9th Spacecraft Charging Technology Conference, (2005) CD-ROM, English

  [Refereed]

  Scientific journal


• Hyperthermal atomic oxygen interaction with MoS(2) lubricants relevance to space environmental effects in low earth orbit - atomic oxygen-induced oxidation

  M Tagawa, K Yokota, N Ohmae, K Matsumoto, M Suzuki

  Effect of 5 eV atomic oxygen beam exposure on the surface properties of sputter-deposited and single-crystal molybdenum disulfide (MoS(2)) were evaluated in the light of space environmental effects in low earth orbit. X-ray photoelectron spectra indicated that the loss of sulfur from the atomic oxygen exposed MoS2 surface was significant, especially for the sputter-deposited samples. This is due to the formation and gasification of the volatile product, SO. It was also identified that Mo atoms at the surface were oxidized to form MoO(3). The amount of oxygen increased within a depth of 22 nm from the surface, whereas loss of sulfur was only observed within 3 nm. It was thus concluded that the chemical change of MoS(2) due to atomic oxygen attack is limited to the surface layer of the MoS(2)-sputtered lubricant.

  SPRINGER/PLENUM PUBLISHERS, Nov. 2004, TRIBOLOGY LETTERS, 17(4) (4), 859 - 865, English

  [Refereed]

  Scientific journal


• Effect of water adsorption on microtribological properties of hydrogenated diamond-like carbon films

  M Tagawa, M Ikemura, Y Nakayama, N Ohmae

  Microtribological properties of diamond-like carbon (DLC) films in the presence of water molecule have been studied. The amount of water adsorbed on DLC films was measured by the quartz crystal microbalance (QCM), while microtribological properties of the film were evaluated by an environment-controlled microtribometer. The hydrogenated-DLC showed an advancing water contact angle of 97degrees, indicating a relatively hydrophobic surface. No hysteresis in adsorption and desorption isotherms were observed. This suggests an absence of micropores at the DLC surface. The greatest adhesion and friction forces between a W-tip and DLC films deposited onto QCM were observed at a water coverage of 2-3 monolayers, which corresponds to a relative humidity of 70-80%. This abrupt increase in adhesion was explained by the generation of a meniscus from the condensed water between tip and DLC surface. The atomically. at DLC surface showed maximum adhesion and friction forces at lower humidity than those of DLC on OCM, implying the importance of surface texturing, which reduces the effect of water condensation.

  KLUWER ACADEMIC/PLENUM PUBL, Oct. 2004, TRIBOLOGY LETTERS, 17(3) (3), 575 - 580, English

  [Refereed]

  Scientific journal


• High friction of vertically aligned carbon nanotube film in microtribology

  KINOSHITA Hiroshi, KUME Ippei, TAGAWA Masahito, OHMAE Nobuo

  American Institute of Physics (AIP), Aug. 2004, Applied Physics Letters, 85, 14, 2780-2781(14) (14), 2780 - 2781, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Effect of relative intensity of 5 eV atomic oxygen and 172 nm vacuum ultraviolet in the synergism of polyimide erosion

  K Yokota, N Ohmae, M Tagawa

  A quantitative study of the synergistic effect of 5 eV atomic oxygen and 172 nm vacuum ultraviolet radiation exposure was carried out on polyimide samples. The relative intensity of atomic oxygen and ultraviolet was adjusted by rotating the polyimide sample at the crossover point of the beam axes of atomic oxygen and ultraviolet which crossed 90degrees. The erosion rate of polyimide was calculated from the resonant frequency of the quartz crystal microbalance on which the polyimide was spin-coated. It was confirmed that the ultraviolet exposure to the atomic oxygen-exposed polyimide promoted the desorption of carbon oxides from the surface. In contrast, no mass change was detected when ultraviolet irradiated the polyimide surface without atomic oxygen exposure. By changing the relative intensity of atomic oxygen and ultraviolet, increases in erosion rates up to 400% were observed when the relative ultraviolet/atomic oxygen flux intensity reached 10(-14) mJ atom(-1).

  SAGE PUBLICATIONS LTD, Jun. 2004, HIGH PERFORMANCE POLYMERS, 16(2) (2), 221 - 234, English

  [Refereed]

  Scientific journal


• Synergistic study on atomic oxygen-induced erosion of polyethylene with vacuum ultraviolet

  M Tagawa, K Yokota, N Ohmae

  Ground-based experimental results on atomic oxygen-induced erosion of polyethylene with simultaneous vacuum ultraviolet (VUV) are reported. In situ mass-loss measurement was made using a quartz crystal microbalance with a mass resolution of 2 ng. A laser detonation atomic oxygen beam source was used to simulate collision energy of atomic oxygen with materials in low Earth orbit. To change relative intensity of atomic oxygen and VUV, the sample was rotated with an axis perpendicular both to the axes of atomic oxygen and VUV. It was observed that the erosion rate of polyethylene was increased 30-100% by a simultaneous VUV exposure depending on the incident angle of atomic oxygen. No contribution of temperature increase was confirmed in the polyethylene erosion. The experimental results, suggested that two reaction pathways exist in the simultaneous atomic oxygen and VUV exposure conditions. It is suggested that the synergistic effect on polyethylene erosion is emphasized in the exposure condition where relative atomic oxygen flux is low against VUV flux.

  AMER INST AERONAUT ASTRONAUT, May 2004, JOURNAL OF SPACECRAFT AND ROCKETS, 41(3) (3), 345 - 349, English

  [Refereed]

  Scientific journal


• Energy accommodation in hyperthermal gas-surface collisions: Aerobraking in planetary atmospheres

  TK Minton, M Tagawa, GM Nathanson

  We have utilized a molecular beam-surface scattering technique to measure energy accommodation coefficients for the collisions of fast Ar atoms and CO2 molecules with surfaces that are representative of materials on the solar panels of the Mars Global Surveyor and Magellan spacecraft. Pulsed beams of fast atoms or molecules, with nominal kinetic energies of 4.27 or 12.6 eV, were directed at a target surface, and the elastically scattered species were monitored with a rotatable mass spectrometer detector. Time-of-flight distributions were collected for species that were scattered both in and out of the plane defined by the incident beam and surface normal. A thorough study of fast CO2 and Ar scattering from the sample surfaces with an incident angle of either 30 or 0 deg has yielded average energy accommodation coefficients in the range 0.91-0.95. These results suggest that the overwhelming majority of the gas-surface collision energy during aerobraking is transferred to heat at the surface.

  AMER INST AERONAUT ASTRONAUT, May 2004, JOURNAL OF SPACECRAFT AND ROCKETS, 41(3) (3), 389 - 396, English

  [Refereed]

  Scientific journal


• 低地球軌道上の原子状酸素環境利用に向けての収束化技術の開発（２）

  TAGAWA Masahito, YOKOTA Kumiko, OHMAE Nobuo

  2004, 第20回宇宙利用シンポジウム講演予稿集, 312-315, Japanese

  International conference proceedings


• 低地球軌道上の原子状酸素にりよるシリコン酸化膜形成とその特徴

  YOKOTA kumiko, OHMAE Nobuo, TAGAWA Masahito

  2004, 第20回宇宙利用シンポジウム講演予稿集, 308-311, Japanese

  Scientific journal


• 低軌道宇宙環境に曝露した固体潤滑剤のトライボロジー特性評価

  MATSUMOTO Koji, AKIYAMA Masao, KISHI Katsuhiro, TAGAWA Masahito

  2004, 独立行政法人宇宙航空研究開発機構 第2回総合技術研究本部 公開研究発表会前刷集, 127-130, Japanese

  International conference proceedings


• 円周走査型原子間力顕微鏡の開発

  木之下 博, 酒向 智也, 田川 雅人, 大前 伸夫, 小宮 広志

  日本トライボロジ-学会, 2004, トライボロジスト, 49, 11, 886-893(11) (11), 886 - 893, Japanese

  [Refereed]

  Scientific journal


• Surface Reaction of Atomic Oxygen with Spin-Coated Polymide Films: Temperature Dependence of the Reaction Efficienc

  SEIKYU Shinsuke, YOKOTA Kumiko, TAGAWA Masahito, OHMAE Nobuo

  2004, Proceedings of the 24th International Symposium on Space Technology and Science, Paper No.2004-c-39, English

  [Refereed]

  International conference proceedings


• Spatially resolved wettability control of polymer surfaces using laser-detonated hyperthermal atomic beams

  M Tagawa, Y Ohki, K Yokota, N Ohmae

  The fundamental properties of hyperthermal atomic oxygen or atomic fluorine-exposed polyimide and polyethylene surfaces, based on the analytical results by X-ray photoelectron spectroscopy and contact angle measurements, are reported. It was observed that CF, CF2 or CF3 moieties were formed at the atomic-fluorine-exposed polymer surfaces depending on the fluence, whereas carbonyl and carboxyl groups were formed at the atomic oxygen-exposed polymer surfaces. Advancing contact angles of water can be controlled from 60 to 150 degrees by varying the atomic oxygen or atomic fluorine fluence. It was also demonstrated that a selected area on the target surface could be processed with this method using a fine metal mask. The behavior of a water droplet on polymer surfaces could be controlled by the spatially resolved surface modification using hyperthermal atomic beams.

  VSP BV, 2004, JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 18(2) (2), 243 - 259, English

  [Refereed]

  Scientific journal


• Enhancement of atomic Oxygen-induced Erosion of Polymide under Simultaneous Vacuum Ultraviolet Exposure Conditions ; A Quantitative Study

  YOKOTA Kumiko, SEIKYU Shinsuke, TAGAWA Masahito, OHMAE Nobuo

  2004, Proceedings of the 24th International Symposium on Space Technology and Science, Paper No.2004-c-38, English

  [Refereed]

  International conference proceedings


• Ellipsometric Study on the Oxidation of silicon by atomic Oxygen in Space Environment

  SOGO Chie, TSUMAMOTO Shinnosuke, YOKOTA Kumiko, TAGAWA Masahito, OHMAE Nobuo

  2004, Proceedings of the 24th International Symposium on Space Technology and Science, Paper No.2004-h-02, English

  [Refereed]

  International conference proceedings


• A computer Simulation of the Surface Scattering Event of Energetic Atomic Oxygen for Developing Atomic Oxygen Concentrator

  DOI Hiroaki, YOKOTA Kumiko, TAGAWA Masahito, OHMAE Nobuo

  2004, Proceedings of the 24th International Symposium on Space Technology and Science, Paper No.2004-h-03, English

  [Refereed]

  International conference proceedings


• High growth rate of vertically aligned carbon nanotubes using a plasma shield in microwave plasma-enhanced chemical vapor deposition

  H Kinoshita, Kume, I, H Sakai, M Tagawa, N Ohmae

  PERGAMON-ELSEVIER SCIENCE LTD, 2004, CARBON, 42(12-13) (12-13), 2753 - 2756, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Wettability of ultraviolet excimer-exposed PE, PI and PTFE films determined by the contact angle measurements

  K Gotoh, Y Nakata, M Tagawa, M Tagawa

  Effects of the exposure of ultraviolet (UV) excimer light on the physicochemical surface properties of polymer films were investigated by contact angle measurements and X-ray photoelectron spectroscopy (XPS). The UV light at wavelength of 172 nm was exposed to polyethylene (PE), polyimide (PI), and polytetrafluoroethylene (PTFE) films in ambient air. The advancing and receding contact angles of water on the unexposed and UV-exposed films were determined by the sessile drop and the Wilhelmy methods as a measure of the wettability. For the PE and PI films, remarkable decrease in the water contact angle was accomplished by the UV exposure of several or several 10 s. The XPS data showed that such increase in the wettability was attributed to the increased atomic oxygen concentration at the film surfaces. The wettability of the PTFE film did not change due to the UV exposure. When the UV-exposed PE and PI films were stored in ambient air, the increase in the water contact angle, i.e. the hydrophobic recovery, was observed over a time scale of several days. It was suggested that the gasification of the low-molecular weight oxidized materials as well as the reorientation and the migration of polymer chains in the oxidized surface layer was responsible for the hydrophobic recovery in air. The UV exposure was also attempted to the PI film being covered with a metal mesh to prepare the film having both non-exposed and UV-exposed surface regions. The differences in the advancing and receding contact angles between the both regions were observed on the continuous weight recording at constant interfacial moving velocity by the Wilhelmy method. The Wilhelmy method in combination with the UV lithography technique enabled the simultaneous evaluation of the wettabilities of the treated and untreated surfaces. (C) 2003 Elsevier B.V. All rights reserved.

  ELSEVIER SCIENCE BV, Aug. 2003, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 224(1-3) (1-3), 165 - 173, English

  [Refereed]

  Scientific journal


• Adhesion and friction of hydrogenated DLC films with adsorbed water studied by in-situ AFM/FFM

  Nobuo Ohmae, Masahito Tagawa

  Influence of relative humidity on tribology of diamond-like carbon (DLC) has been studied using an in-situ microtribometer. In order to simulate the relative humidity in tribological experiments, water vapor is often back-filled in a vacuum chamber at an appropriate pressure. However, the relation between vapor pressure and relative humidity has not yet been fully understood. Simultaneous use of a hygrometer, a high-pressure vacuum gage and a quartz crystal microbalance (QCM) solved this problem in this study. For DLC films deposited on QCM, an abrupt increase in adhesion and friction forces occurred at the relative humidity of 70-80 %, resulting from the meniscus force by the condensation of water vapor. For atomically smooth DLC films on the Si(001), the highest adhesion and friction forces were found at the relative humidity of 40-60 %. © 2004 Elsevier B.V. All rights reserved.

  Elsevier, 2003, Tribology Series, 43, 487 - 493, English

  International conference proceedings


• Comparison of polyimide film surface properties exposed to real and simulated space environments: Relevance of atomic oxygen effects to wettability in space

  M Tagawa, N Ohmae, Y Nakata, K Gotoh, M Tagawa

  Polyimide surfaces exposed to a real space environment in low Earth orbit (STS-8, STS-46 and SFU missions) are compared to those exposed to a simulated atomic oxygen environment created by a hyperthermal atomic oxygen beam facility. The surface analytical results of the samples exposed to a simulated space environment showed that both the roughness and the oxygen concentration at the atomic oxygen-exposed polyimide surfaces increased with increasing atomic oxygen fluence. The advancing and receding contact angles of water decreased with increasing oxygen concentration at the polyimide surfaces. The Lifshitz-van der Waals component and the acid and base parameters of the surface free energy of polyimide films were calculated from the contact angles of three probe liquids. The base parameter increased with increasing oxygen concentration, whereas the Lifshitz-van der Waals component and the acid parameter did not show any significant change. These analytical results agree with the X-ray photoelectron spectroscopic data showing the formation of surface functional groups due to atomic oxygen exposure. The ground-based experimental results are consistent with the analysis of the three flight samples. It was demonstrated in this study that polyimide surfaces in a low Earth orbit space environment became high-energy surfaces due to the bombardment of atomic oxygen.

  VSP BV-C/O BRILL ACAD PUBL, 2003, POLYIMIDES AND OTHER HIGH TEMPERATURE POLYMERS: SYNTHESIS, CHARACTERIZATION AND APPLICATIONS, VOL 2, 419 - 435, English

  [Refereed]

  International conference proceedings


• Use of quartz crystal microbalance on the polymer degradation studies regarding atomic oxygen activities in low earth orbit

  M Tagawa, K Yokota, H Kinoshita, N Ohmae

  Usefulness of the application of quartz crystal microbalance (QCM) on the atomic oxygen-induced erosion study of polymeric material is presented. Polyimide film was spin-coated on an Au electrode of QCM sensor crystals and mass change of the polymer film was measured from the frequency shift of the QCM during atomic oxygen beam exposures. Extremely high resolution in mass of QCM measurement is suitable for in-situ mass loss measurement of polymers during AO beam exposure even though its dynamic range of mass measurement is narrow. In this presentation, we are reporting our recent research results on atomic oxygen-induced polymer degradation using QCM; (1) non-linear mass loss phenomenon during atomic oxygen-induced erosion, (2) temperature dependence of polymer erosion due to hyperthermal atomic oxygen beam exposure, and (3) comparison of atomic oxygen flux measurements using Ag-QCM and Kapton witness sample.

  ESA PUBLICATIONS DIVISION C/O ESTEC, 2003, PROCEEDINGS OF THE 9TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN A SPACE ENVIRONMENT, 540, 247 - 252, English

  [Refereed]

  International conference proceedings


• Temperature and impingement angle dependences of atomic oxygen-induced erosion of polyimide and polyethylene films measured by quartz crystal microbalance

  M Tagawa, K Yokota, T Kida, N Ohmae

  Herein, the ground-based experimental results of temperature and impingement angle dependences of erosion rate of polyimide and polyethylene films under hyperthermal atomic oxygen beam exposures are reported. The in-situ mass loss measurement was made during the atomic oxygen exposure by using a quartz crystal microbalance (QCM). A 5 eV atomic oxygen beam was generated with a laser detonation-type atomic oxygen beam source. The translational energy of the atomic oxygen beam was approximately 5.1 eV, and the typical flux of the beam was 6.5 x 10(14) atom/cm(2)/s at the sample position. The polyimide and polyethylene films used in this study were spin-coated on QCM sensor crystals and the shifts in resonance frequency of polymer-coated QCMs were recorded with a mass resolution of 2 ng. It was observed that the erosion rates of both polyimide and polyethylene followed cosine function with incident angle of atomic oxygen. These results were explained by considering microscale roughness at the surface. The temperature dependence of erosion rate of polymers was also examined in the temperature range of 253 K to 353 K. The Arrhenius plots gave the activation energies of gasification reaction of 10(-3) to 10(-4) eV for both materials. It is, thus, concluded that the erosion rate of polymers in low Earth orbit is temperature independent due to the high collision energy of atomic oxygen.

  SPRINGER, 2003, PROTECTION OF MATERIALS AND STRUCTURES FROM SPACE ENVIRONMENT, 5, 391 - 399, English

  [Refereed]

  International conference proceedings


• 原子ビームを用いた細胞接着パターンの作成

  ADACHI Taiji, KAJITA Fumiaki, SATO Katsuya, MATSUMOTO Koshi, TAGAWA Masahito

  This study aimed to develop a new cell micro-patterning method by controlling material surface affinity of the cell using atomic oxygen beam exposure. Surfaces of low-density polyethylene (LDPE) and tetrafluoroethylene-hexafluoropropylene (FEP) were exposed to the atomic oxygen beam. On the LDPE surface, the roughness measured by atomic force microscopy (AFM) did not change much, however, the oxygen concentration on the surface measured by X-ray photoelectron spectroscopy (XPS) significantly increased that resulted in increase in wettability. Contrary to this, on the FEP surface, the oxygen concentration showed no significant change, but roughness of the surface remarkably increased and the wettability decreased. As a result of the surface modification, affinity of the osteoblastic cells on the FEP surface increased, which was also confirmed by increase in the cell area. Finally, cell micro-patterning on the FEP surface was carried out based on difference in the affinity between modified and unmodified surfaces patterned by a masking method.

  The Japan Society of Mechanical Engineers, 2003, 日本機械学会論文集A編, 69(688),118-124(688) (688), 1782 - 1788, Japanese

  [Refereed]

  Scientific journal


• Wear-life of the molybdenum disulfide sputtered film under hyperthermal atomic oxygen bombardment: In-situ wear-life evaluations

  M Tagawa, M Muromoto, S Hachiue, K Yokota, N Ohmae, K Matsumoto, M Suzuki

  Wear-life of the MoS(2) film was evaluated by in-situ tribological testing under 5 eV atomic oxygen exposures which simulate LEO atomic oxygen environment. A combination of a laser-detonation atomic oxygen source and a conventional pin-on-disk friction tester was used to perform tribological tests. It was confirmed that the friction coefficient was not affected by atomic oxygen exposure when atomic oxygen fluence was low; however, the friction coefficient increased with increasing atomic oxygen fluence and it reached as high as 0.05 (seven times larger than the normal value) at the atomic oxygen fluence of 3.4 x 10(16) atoms/cm(2)/cycle. Effect of atomic oxygen on the wear-life of the film has much more drastic. With atomic oxygen fluence of 1.7 x 10(16) atoms/cm(2)/cycle, wear-life of the film was reduced one ninth of the ex-situ testing result of the same film. It was also observed that the wear-life of the film was inversely proportional to the atomic oxygen fluence between every sliding motion.

  ESA PUBLICATIONS DIVISION C/O ESTEC, 2003, 10TH EUROPEAN SPACE MECHANISMS AND TRIBOLOGY SYMPOSIUM, PROCEEDINGS, 524, 311 - 314, English

  International conference proceedings


• Temperature dependence in erosion rates of polyimide under hyperthermal atomic oxygen exposures

  K Yokota, M Tagawa, N Ohmae

  AMER INST AERONAUT ASTRONAUT, Jan. 2003, JOURNAL OF SPACECRAFT AND ROCKETS, 40(1) (1), 143 - 144, English

  [Refereed]

  Scientific journal


• A quantitative study in synergistic effects of atomic oxygen and ultraviolet regarding polymer erosion in LEO space environment

  K Yokota, S Seikyu, M Tagawa, N Ohmae

  Effect of relative intensity of atomic oxygen and vacuum ultraviolet in the synergistic effect of polyimide erosion was investigated. The relative intensity of atomic oxygen and ultraviolet was adjusted by rotating the polyimide sample at the crossover point of the beam axes of atomic oxygen and ultraviolet which crossed 90 degrees. The erosion rate of polyimide was measured by a quartz crystal microbalance. It was confirmed that the ultraviolet exposure at the atomic oxygen-exposed polyimide promoted the desorption of carbon oxides from the surface. In contrast, no mass change was detected when ultraviolet irradiated the polyimide surface without simultaneous atomic oxygen exposure. By changing the relative intensity of atomic oxygen and ultraviolet, increase in erosion rate up to 400 % was observed when relative ultraviolet intensity is high.

  ESA PUBLICATIONS DIVISION C/O ESTEC, 2003, PROCEEDINGS OF THE 9TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN A SPACE ENVIRONMENT, 540, 265 - 272, English

  International conference proceedings


• Application of quartz crystal microbalance for polymer degradation studies regarding atomic oxygen activities in low earth orbit.

  TAGAWA Masahito, YOKOTA Kumiko, KINOSHITA H, OHMAE Nobuo

  2003, Proceedings of the 9th International Symposium on Materials in a Space., ESA SP-540,247-252, English

  International conference proceedings


• Effects of ambient air exposure on atomic oxygen-exposed Kapton-H films

  M Tagawa, K Yokota, N Ohmae, H Kinoshita

  In research reporting on the effect of ambient air exposure on atomic oxygen-exposed Kapton-H film, the surface oxygen concentration of atomic oxygen-exposed Kapton-H increased with increasing atomic oxygen fluence and reached a saturated value even without ambient air exposure. These results are contradictory to the previously reported results by Grossman et al. (Grossman, E., Lifshitz, Y., Wolan, J. T., Mount, C. K., and Hoflund, G. B., "In Situ Erosion Study of Kapton Using Novel Hyperthermal Oxygen Atom Source," Journal of Spacecraft and Rockets, Vol. 36, No. 1, 1999, pp. 75-78). From the x-ray photoelectron spectroscopic analysis of the atomic oxygen-exposed Kapton-H with and without ambient air exposures, it was concluded that the atomic oxygen exposure creates a highly oxidized surface and the carbon and oxygen concentrations were affected by the subsequent ambient air exposure. These results clearly indicate that the effect of air exposure should be taken into consideration in the analysis of surface chemistry of materials exposed to low-Earth-orbit space environment.

  AMER INST AERONAUT ASTRONAUT, May 2002, JOURNAL OF SPACECRAFT AND ROCKETS, 39(3) (3), 447 - 451, English

  [Refereed]

  Scientific journal


• Impingement angle dependence of erosion rate of polyimide in atomic oxygen exposures

  K Yokota, M Tagawa, N Ohmae

  AMER INST AERONAUT ASTRONAUT, Jan. 2002, JOURNAL OF SPACECRAFT AND ROCKETS, 39(1) (1), 155 - 156, English

  [Refereed]

  Scientific journal


• Nonlinear phenomena in the mass loss of polyimide films under hyperthermal atomic oxygen beam exposure

  H Kinoshita, M Tagawa, K Yokota, N Ohmae

  Erosion phenomenon of polyimide film under the hyperthermal atomic oxygen beam exposure, which is a simulated low Earth orbit space environment, has been investigated. The polyimide film was spin-coated on a sensor crystal of a quartz crystal microbalance, and the mass of the film was measured under the atomic oxygen beam exposure. The spin-coated polyimide film which was exposed to a 4.7 eV atomic oxygen beam showed a mass gain at the beginning of the reaction and then steady-state mass loss followed. The experimental results of the mass change was analysed by the computational model, and the results showed that the carbon abstraction rate at the oxygen-adsorbed sites was two orders higher than that at the unoxidized polyimide surface. The computational results suggested that a large fraction of the carbon abstraction reaction occurred in the oxygen-adsorbed site through a Langmuir-Hinshelwood reaction mechanism.

  SAGE PUBLICATIONS LTD, Dec. 2001, HIGH PERFORMANCE POLYMERS, 13(4) (4), 225 - 234, English

  [Refereed]

  Scientific journal


• Oxidation properties of hydrogen-terminated Si(001) surfaces following use of a hyperthermal broad atomic oxygen beam at low temperatures

  M Tagawa, K Yokota, N Ohmae, H Kinoshita, M Umeno

  The oxidation properties of an H-terminated Si(001) surface following the use of a hyperthermal broad atomic oxygen beam have been studied at low temperatures. Effects of sample temperature, flux and energy of the impinging atomic oxygen on the oxidation of silicon were investigated by X-ray photoelectron spectroscopy. It was confirmed that oxide growth at the surface was achieved even at room temperature and the oxide thickness reached a terminal thickness of a few nanometers depending upon the oxidation conditions. The oxidation process was divided into two stages: the fast oxidation stage and the subsequent slow oxidation stage. It was also confirmed that the reaction yield of atomic oxygen with Si increased with increasing translational energy. The characteristic feature of beam oxidation was explained by the effect of energy accommodation from the impinging oxygen atom to the surface silicon atom.

  INST PURE APPLIED PHYSICS, Oct. 2001, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 40(10) (10), 6152 - 6156, English

  [Refereed]

  Scientific journal


• Material Degradation Phenomena in Low Earth Orbit Space Environment and Their Ground-based Simulations

  TAGAWA Masahito

  The Vacuum Society of Japan, May 2001, Journal of the Vacuum Society of Japan, 44(5) (5), 506 - 511, Japanese


• Surface characterization of atomic oxygen beam-exposed polyimide films using contact angle measurements

  K Gotoh, M Tagawa, N Ohmae, H Kinoshita, M Tagawa

  Polyimide surfaces exposed to simulated low Earth orbit space environment, i.e., under hyperthermal atomic oxygen bombardment, were characterized by using atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurements. The surface analytical results showed that the roughness and the O/C ratio at the atomic oxygen-exposed polyimide surface increased with increasing atomic oxygen fluence. The advancing and receding contact angles decreased with increasing O/C ratios at the polyimide surfaces. The Lifshitz-van der Waals component, the acid and base parameters of the surface free energy of polyimide films were calculated from the contact angles. The base parameter increased with increasing O/C ratio, whereas the acid parameter and the Lifshitz-van der Waals component did not show a remarkable change. These analytical results agree with the in situ XPS data showing the formation of surface functional groups due to atomic oxygen exposure. It was demonstrated in this study that the polyimide surface in a low Earth orbit space environment may become hydrophilic due to the bombardment by atomic oxygen.

  SPRINGER-VERLAG, Mar. 2001, COLLOID AND POLYMER SCIENCE, 279(3) (3), 214 - 220, English

  [Refereed]

  Scientific journal


• Volume diffusion of atomic oxygen in α-SiO2 protective coating

  Masahito Tagawa, Kumiko Yokota, Nobuo Ohmae, Hiroshi Kinoshita

  The minimum thickness for an amorphous silicon dioxide (α-SiO2) protective coating required to prevent volume diffusion of atomic oxygen in a low Earth orbit (LEO) was evaluated by measuring the oxide thickness formed on Si(001) wafers in a hyperthermal atomic oxygen beam. The thickness of oxide film was measured by x-ray photoelectron spectroscopy. The diffusion length of atomic oxygen in α-SiO2 at temperatures between 297 K and 493 K, where exterior surfaces of a spacecraft may be heated in LEO, shows temperature and flux dependences, i.e. the diffusion length of atomic oxygen increases with increasing temperature and beam flux. It was also demonstrated that the atomic oxygen fluence is not a primary factor of the diffusion length since the oxide growth obeys a parabolic law. The ground-based testing condition to evaluate performances of protective coatings are also discussed, based on the experimental data obtained in the experiments.

  IOP, Mar. 2000, High Performance Polymers, 12(1) (1), 53 - 63, English

  [Refereed]

  Scientific journal


• The Evaluation of Survivability of the Polymeric Materials in Space Environment Using a Hyperthermal Atomic Oxygen Beam

  TAGAWA Masahito

  The Society of Polymer Science, Japan, Feb. 2000, Kobunshi, 49(2) (2), 74 - 74, Japanese


• Effect of Low-Energy lon Bombardment upon Field-Stimulated Exoelectron Emission from Tangsten Surfaces.

  Shiota Tadashi, Kibi Sinji, Yamamoto Ryo, Tagawa Masahito, Ohmae Nobuo, Umeno Masataka

  The field-stimulated exoelectron emission (FSEE) from a tungsten surface bombarded by helium ions with incident energies ranging from 300 to 580 eV was investigated. When a tip was cooled down to 185 K, FSEE was clearly detected at the ion-bombarded tungsten surface with incident energies higher than 500 eV which corresponds to the sputtering threshold of tungsten atoms. A decay of FSEE intensity was also observed after the ion bombardment. In contrast, FSEE was not obvious at the tip temperature of 300 K. These experimental results would be explained by the emission model which is related to a rearrangement of surface tungsten atoms distorted by the ion bombardment.

  The Japan Society of Applied Physics, 2000, Japanese Journal of Applied Physics, 39(2) (2), L110 - L112, English


• Surface Reaction of a Low Flux Atomic Oxygen Beam with a Spin-Coated Polyimide Film: Translational Energy Dependence on the Reaction Efficiency.:Translational Energy Dependence on the Reaction Efficiency

  KINOSHITA Hiroshi, TAGAWA Masahito, UMENO Masataka, OHMAE Nobuo

  Translational energy dependence of the atomic oxygen reactivity with polyimide films is reported. An ion beam type atomic oxygen source was used to study atomic oxygen reactivity in a wide range of translational energies. Mass change of polyimide films was measured by a frequency shift of the quartz crystal microbalance during atomic oxygen beam exposures. The experimental result showed strong translational energy dependence of mass change of the polyimide film, i.e., mass gain was observed at the translational energies below 30eV whereas mass loss was observed at the higher translational energies. X-ray photoelectron spectra indicated that pyromelliticdianhydride in the polyimide structure was degradated by the 5eV atomic oxygen reaction. Decomposition of oxydianiline was also obvious at higher translational energies. The mass gain observed in this study was explained by the absence of adsorbed oxygen at the polyimide surfaces due primarily to the low flux of the beam, which may lead to the suppression of debonding of polymer backbones.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 1999, JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 47(541) (541), 88 - 94, Japanese


• The Surface Reaction of a Low Flux Atomic Oxygen Beam with a Spin-Coated Polyimide Film: The Effect of Simultaneous UV Irradiation.:The Effect of Simultaneous UV Irradiation

  TAGAWA Masahito, SUETOMI Toru, KINOSHITA Hiroshi, UMENO Masataka, OHMAE Nobuo

  The synergistic effect of atomic oxygen and ultraviolet rays on the spin-coated polyimide film is investigated. The X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy suggest that the formation of carbonyl group at the film surface occurs during atomic oxygen exposures. The mass loss of the polyimide film and the enhancement carbon dioxide formation are observed during simultaneous irradiation of the low flux atomic oxygen and ultraviolet rays. These experimental results are explained by the photo-assisted chemical reaction of carbonyl groups formed by atomicoxygen attack. The fact that the synergistic effect of atomic oxygen and ultraviolet rays is obvious on the polyimide film, which is known as the material showing no synergistic effect in low Earth orbit, may reveal the importance of relative intensities of atomic oxygen and ultraviolet rays on the ground-based synergistic testing of the materials.

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 1999, JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 47(543) (543), 182 - 187, Japanese


• Surface reaction of a low flux atomic oxygen beam with a spin-coated polyimide film: Translational energy dependence on the reaction efficiency

  H Kinoshita, M Tagawa, M Umeno, N Ohmae

  Translational energy dependence of the atomic oxygen reactivity with polyimide films is reported. The ion beam type atomic oxygen source was used to study atomic oxygen reactivity in a wide range of translational energies. Mass change of the polyimide films was measured by a frequency shift of the quartz crystal microbalance during atomic oxygen beam exposures. The experimental result showed strong translational energy dependence of mass change of the polyimide film, i.e., mass gain was observed at the translational energies below 30 eV whereas mass loss was observed at the higher translational energies. X-ray photoelectron spectra indicated that PMDA in the polyimide structure was degradated by the 5 eV atomic oxygen reaction. Decomposition of ODA was also obvious by the atomic oxygen attacks at higher translational energies. The mass gain observed in this study was explained by the absence of adsorbed oxygen on the polyimide surfaces due primarily to the low flux of the beam. This may lead to the suppression of scission of the polymer chain.

  JAPAN SOC AERONAUT SPACE SCI, Aug. 1998, TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 41(132) (132), 94 - 99, English

  [Refereed]

  Scientific journal


• A fast atomic oxygen beam facility with in situ testing/analysis capabilities

  H Kinoshita, J Ikeda, M Tagawa, M Umeno, N Ohmae

  A fast atomic oxygen beam facility consisting of a beam source, a mass spectrometer, an Auger electron spectroscope, a scanning tunneling microscope, and a friction tester has been developed to investigate interaction of energetic atomic oxygen with solid surfaces. The fast atomic oxygen beam has been characterized by time of flight distribution, quadrupole mass spectrometry, and quartz crystal microbalance. The time of flight distribution of the beam has shown that the average translational energy of the atomic oxygen beam reaches 4.7 eV and that the full width at half-maximum is 5.5 eV. A flux of the atomic oxygen is calculated from the frequency shift of the quartz crystal microbalance with silver electrodes, and typical flux of the atomic oxygen beam being 4.0 X 10(12) atoms/cm(2) s. The flux of atomic oxygen of this source is fairly low, but is corresponding to that in the altitude of 500 km in low Earth orbit. The surface sensitive analysis methods equipped with the facility, such as Auger electron spectroscopy and scanning tunneling microscopy, have provided changes in the surface composition and morphology caused by the atomic oxygen exposure, without receiving any effect of ambient air. The ultrahigh vacuum friction tester especially designed for this facility is used to measure tribological properties of solid lubricants under the atomic oxygen exposures. Such in situ testing capability of this facility enables fundamental research for understanding the reaction scheme of atomic oxygen as well as engineering-oriented research for obtaining high reliability of the space systems. (C) 1998 American Institute of Physics. [S0034-6748(98)02806-8].

  AMER INST PHYSICS, Jun. 1998, REVIEW OF SCIENTIFIC INSTRUMENTS, 69(6) (6), 2273 - 2277, English

  [Refereed]

  Scientific journal


• Formation of Thin Oxide Films on Room-Temperature Silicon (100) by Exposure to a Neutral Beam of Hyperthermal Atomic and Molecular Oxygen.

  Tagawa Masahito, Ema Tatsuhiko, Kinoshita Hiroshi, Ohmae Nobuo, Umeno Masataka, Minton Timothy K.

  Silicon (100) surfaces at room temperature were oxidized in a hyperthermal beam containing nearly equal fractions of atomic and molecular oxygen. An oxide layer with a terminal thickness of 4.5 nm was formed on the Si surfaces, and this layer was composed mostly of silicon dioxide (SiO₂). However, a significant fraction of suboxide (SiO_x, x<2) was formed at the Si/SiO₂ interface, where the intrinsic stress was high. Post annealing in vacuum at 1000^°C for 30 min decreased the amount of suboxide and stress at the interface.

  The Japan Society of Applied Physics, 1998, Japanese Journal of Applied Physics, 37(12) (12), L1455 - L1457, English


• Space tribology activities in Japan - Laboratory data and flight experiment aboard SFU/EFFU

  Nobuo Ohmae, Hiroshi Kinoshita, Junichi Ikeda, Masahito Tagawa, Masashi Arita, Katsuhiro Kishi, Masahiro Shibata

  This paper describes recent laboratory experiments on space tribology as well as flight experiments aboard SFU/EFFU. Tribological properties of single crystal molybdenum disulfide have been studied during atomic oxygen exposure. Surface characterization of the MoS2 with Auger electron spectroscopy was carried out without breaking vacuum. Small amount of oxygen was detected after exposure to atomic oxygen beam. High start-up friction was obvious in the case of AO-exposed MoS2. An organic binder type spray-bonded MoS2 film flown on the SFU/EFFU showed no difference in tribological performance from the control samople. Moreover, the wear life of the flight sample was even longer than the control sample. This unexpected effect was explained by the polymerization of the binder due to UV exposure in the orbit.

  1997, European Space Agency, (Special Publication) ESA SP, (399) (399), 387 - 391, English

  Scientific journal


• Dissociation dynamics of ClONO2 and relative Cl and ClO product yields following photoexcitation at 308 nm

  Teresa A. Moore, Mitchio Okumura, Masahito Tagawa, Timothy K. Minton

  Chlorine nitrate photolysis at 308 nm has been investigated with a molecular beam technique. Two primary decomposition pathways, leading to Cl + NO3 and ClO + NO2, were observed. The branching ratio between these two respective channels was determined to be 0.67 ± 0.06: 0.33 ± 0.06. This ratio is an upper limit because some of the ClO photoproducts may have undergone secondary photodissociation. The angular distributions of the photoproducts with respect to the direction of polarization of the exciting light were anisotropic. The anisotropy parameters were β = 0.5 ± 0.2 for the Cl + NO3 channel and β = 1.1 ± 0.2 for the ClO + NO2 channel, indicating that dissociation of ClONO2 by either pathway occurs within a rotational period. Weak signal at mass-to-charge ratios of 35 and 51, arising from products with laboratory velocities close to the beam velocity, was observed. While this signal could result from statistical dissociation channels with a total relative yield of 0.07 or less, it is more likely attributable to products from ClO secondary photodissociation or from dissociation of clusters.

  1995, Faraday Discussions, 100, 295 - 307, English

  [Refereed]

  Scientific journal


• Effects of External Stresses on the Low Temperature Thermal Oxidation of Silicon

  Tamura Takao, Tanaka Naoya, Tagawa Masahito, Ohmae Nobuo, Umeno Masataka

  Thermal oxidation of silicon was conducted under the application of external compressive or tensile stress at relatively low oxidation temperature. The effect of external stress appeared in different ways depending on the oxidation temperature. While the stress effect of oxidation at 800°C was well interpreted with the linear-parabolic oxidation model (L-P model), that at a temperature lower than 700°C contradicted the L-P model and strongly suggested the existence of an oxidation reaction of interstitial silicon atoms in the oxide.

  The Japan Society of Applied Physics, Jan. 1993, Jpn J Appl Phys, 32(1) (1), 12 - 16, English


• LOCAL DEVIATION IN CONTACT ANGLES ON HETEROGENEOUS FIBROUS SOLIDS

  M TAGAWA, A YASUKAWA, K GOTOH, M TAGAWA, N OHMAE, M UMENO

  Wetting force measurements in solid/water/n-alkane systems were carried out using carbon fibers, boron fiber, fibrous quartz, and polymeric fibers by the Wilhelmy technique. Contact angles of water were independent of the velocity of the moving three-phase boundary on repyrolyzed PAN-based carbon fibers which did not show any contact angle hysteresis. Hysteresis in contact angles due to surface heterogeneity began to appear after irradiation with atomic oxygen which oxidized the carbon fibers. On atomic oxygen exposed carbon fibers, advancing contact angles increased and receding ones decreased with increasing velocity, and there was a region where both angles were constant. The range of deviations in contact angles due to surface heterogeneity was determined from local deviations in weight traces at the velocity of three-phase boundary of 0.3 mm min-1 where both angles were independent of the velocity. Deviations in contact angles, DELTA-theta, were larger in advancing than in receding for hydrophilic solids (e.g. quartz), and were smaller for hydrophobic solids (e.g. polyethylene).

  VSP BV, 1992, JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 6(6) (6), 763 - 776, English

  [Refereed]

  Scientific journal


• Surface characterization of carbon fiber exposed to 5 eV energetic atomic oxygen beam studied by wetting force measurements

  GOTOH Keiko, Tagawa Masahito, Ohmae Nobuo, Umeno, Yasukawa Akemi, Gotoh Keiko, Tagawa Mieko

  Sep. 1991, Japanese Journal of Applied Physics, 30(9) (9), 2134 - 2138, English

  [Refereed]

  Scientific journal


• CONTACT-ANGLE HYSTERESIS IN CARBON-FIBERS STUDIED BY WETTING FORCE MEASUREMENTS

  M TAGAWA, N OHMAE, M UMENO, K GOTOH, A YASUKAWA, M TAGAWA

  DR DIETRICH STEINKOPFF VERLAG, Aug. 1989, COLLOID AND POLYMER SCIENCE, 267(8) (8), 702 - 706, English

  [Refereed]

  Scientific journal


• ELECTRIC-FIELD DISTRIBUTION OF ELECTRON EMITTER SURFACES

  M TAGAWA, S TAKENOBU, N OHMAE, M UMENO

  AMER INST PHYSICS, Mar. 1987, APPLIED PHYSICS LETTERS, 50(9) (9), 545 - 546, English

  [Refereed]

  Scientific journal

• Feasibility study of Air Breathing Ion Engine by using plasma numerical analysis in discharge chamber

  白川遼, 臼井英之, 三宅洋平, 田川雅人, 山下裕介, 加納直起, 西山和孝

  2019, 宇宙科学技術連合講演会講演集(CD-ROM), 63rd


• 大気吸入型イオンエンジンにおけるECRプラズマ粒子シミュレーション

  白川遼, 臼井英之, 三宅洋平, 田川雅人, 西山和孝

  2018, 日本表面真空学会学術講演会講演要旨集, 2018


• 宇宙用材料を指向した液晶ポリマーへの原子状酸素照射

  小柴康子, 横田久美子, 西本卓馬, 堀家匠平, 福島達也, 田川雅人, 石田謙司

  2018, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 79th


• 低軌道宇宙環境下での木質炭素化膜の微細構造変化

  畑 俊充, 梶本武志, 田川雅人, 小嶋浩嗣

  Jun. 2017, 第 15 回木質炭化学会研究発表会, Japanese


• Current status and future challenges of air breathing ion engine

  安河内翼, 田川雅人, 横田久美子, 三宅洋平, 臼井英之, 西山和孝

  2017, 航空原動機・宇宙推進講演会講演論文集(CD-ROM), 57th


• Experimental study on Air Breathing Ion Engine associate with the numerically calculated electromagnetic wave distribution in the discharge chamber

  安河内 翼, 臼井 英之, 三宅 洋平, 福田 雅人, 横田 久美子, 田川 雅人

  日本航空宇宙学会, 06 Sep. 2016, 宇宙科学技術連合講演会講演集, 60, 3p, Japanese


• Challenges in use of Air Breathing Ion Engine in sub-low earth orbit environment

  安河内 翼, 臼井 英之, 三宅 洋平, 福田 雅人, 横田 久美子, 田川 雅人

  日本航空宇宙学会, 06 Sep. 2016, 宇宙科学技術連合講演会講演集, 60, 3p, Japanese


• Synergistic effect on the ground-based atomic oxygen-induced material erosion experiments

  田川 雅人, 横田 久美子

  日本航空宇宙学会, 06 Sep. 2016, 宇宙科学技術連合講演会講演集, 60, 3p, English


• Cultivation of Research and Project-Support Network for Degradation of Space-Use Materials(2)

  岩田 稔, 田川 雅人, 太刀川 純孝, 平尾 敏雄, 大津 志保

  日本航空宇宙学会, 06 Sep. 2016, 宇宙科学技術連合講演会講演集, 60, 3p, Japanese


• 低軌道宇宙環境耐性をもった木質系炭素膜の微細構造

  畑 俊充, 梶本武司, 田川雅人, 小嶋浩嗣

  Mar. 2016, 第66回日本木材学会大会

  Summary national conference


• Ground-based material durability tests for sub-LEO spacecraft

  田川 雅人, 山崎 勇希, 横田 久美子

  日本航空宇宙学会, 07 Oct. 2015, 宇宙科学技術連合講演会講演集, 59, 3p, English


• Cultivation of Research and Project-Support Network for Degradation of Space-Use Materials

  岩田 稔, 田川 雅人, 太刀川 純孝

  日本航空宇宙学会, 07 Oct. 2015, 宇宙科学技術連合講演会講演集, 59, 4p, Japanese


• Si,Ti添加DLC膜表面酸化反応における原子状酸素衝突エネルギーの影響

  渡邉大樹, 初田光嶺, 古山雄一, 神田一浩, 吉越章隆, 寺岡有殿, 横田久美子, 田川雅人

  20 Mar. 2015, 宇宙航空研究開発機構特別資料 JAXA-SP-, (14-012) (14-012), 95 - 99, Japanese


• Sophistication of the ground-based LEO space environmental effect experiment simulation

  田川 雅人, 横田 久美子

  日本航空宇宙学会, 12 Nov. 2014, 宇宙科学技術連合講演会講演集, 58, 3p, English


• 火星高層大気と宇宙機との相互作用に関する研究(1)レーザーデトネーション法による超熱二酸化炭素ビーム形成

  初田 光嶺, 横田 久美子, 田川 雅人

  日本航空宇宙学会, 12 Nov. 2014, 宇宙科学技術連合講演会講演集, 58, 3p, Japanese


• Wood-based, diamond-like carbon for improved resistance against atomic oxygen

  T. Kajimoto, T. Hata, M. Tagawa, H. Kojima, H. Hayakawa

  May 2014, The 11th International Conference on Protection of Materials and Structures from Space Environment, p.23, English

  Summary international conference


• 超熱原子状酸素照射によるSi‐DLC酸化過程の衝突エネルギー依存

  横田久美子, 田川雅人, 吉越章隆, 寺岡有殿

  03 Mar. 2014, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 61st, ROMBUNNO.17A-F3-5, Japanese


• 定常作動型原子状酸素源の開発とビーム性能評価

  久本泰慶, 西山和孝, 田川雅人, 國中均

  2014, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 61st


• レーザー駆動酸素プラズマからの極端紫外線分光の試み

  田川雅人, 横田久美子, 島村宏之, 木本雄吾, 古賀麻由子, 西村博明

  2013, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 74th


• Hydrogen removal from hydrogenated diamond-like carbon films by exposure to photon and energetic atomic oxygen beams

  Kumiko Yokota, Masahito Tagawa, Koji Matsumoto, Yuichi Furuyama, Akira Kitamura, Kazuhiro Kanda, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  © Springer-Verlag Berlin Heidelberg 2013. Stability of hydrogen in diamond-like carbon (DLC) film under simulated space environment, i.e., hyperthermal atomic oxygen, vacuum ultraviolet (VUV) and soft X-ray exposures has been studied. Hydrogen in DLC was released by exposure to low-energy atomic oxygen beam, whereas the gasification reaction of carbon atom needed collision energy above 3 eV. The desorption process in the deep region required a higher collision energy. The density of hydrogen decreased 11% by atomic oxygen exposure, and was independent of the collision energy. Photon exposure also releases hydrogen from DLC. High-energy photons in soft x-ray promote the hydrogen desorption even from deeper region with high efficiency. It was considered that soft x-ray could release bonded hydrogen which is not released by VUV or atomic oxygen exposures.

  01 Jan. 2013, Astrophysics and Space Science Proceedings, 32, 531 - 540


• 原子状酸素照射による木質炭素化物Si焼結体表面における構造変化の解明

  梶本武志, 畑俊充, 小嶋浩嗣, 田川雅人, 早川基

  28 Jun. 2012, 第10回木質炭化学会発表会, 岩手県、盛岡市, Japanese


• Si添加高水素DLC膜への原子状酸素照射による保護膜形成過程の衝突エネルギー依存

  田川雅人, 横田久美子, 吉越章隆, 寺岡有殿

  29 Feb. 2012, 応用物理学関係連合講演会講演予稿集(CD-ROM), 59th, ROMBUNNO.18A-B6-1, Japanese


• オーガナイズドセッション：宇宙材料の熱物性とシステムデザイン

  田川 雅人, 太刀川 純孝, 島崎 一紀

  2012, 熱物性, 26(1) (1), 34, Japanese

  [Refereed]

  Meeting report


• Evaluation and application of the EUV emitted from a laser-detonation atomic oxygen space environmental simulator: FY2011 repor

  M. Tagawa, K. Yokota, H. Shimamura, Y. Kimoto, M. Koga, H. Nishimura

  2012, 大阪大学レーザーエネルギー学研究センター平成22年度共同利用・共同研究成果報告書, 201 - 202, English

  Meeting report


• 原子状酸素照射時におけるSi添加高水素DLC膜からの揮発性反応生成物脱離

  田川雅人, 横田久美子, 岸田和博, 古山雄一, 戸出真由美, 吉越章隆, 寺岡有殿, MINTON Timothy K

  16 Aug. 2011, 応用物理学会学術講演会講演予稿集(CD-ROM), 72nd, ROMBUNNO.30P-K-6, Japanese


• 宇宙用木質材料の耐腐食性の向上

  梶本武志, 畑俊充, 田川雅人, 小嶋浩嗣, 早川基, 山川宏, 上田義勝

  27 May 2010, 木質炭化学会研究発表会講演要旨集, 8th, 58 - 59, Japanese


• 高水素化DLC膜からの水素脱離に対する表面金属酸化膜の効果

  田川雅人, 横田久美子, 古山雄一, 戸出真由美, 吉越章隆, 寺岡有殿

  03 Mar. 2010, 応用物理学関係連合講演会講演予稿集(CD-ROM), 57th, ROMBUNNO.19P-W-1, Japanese


• Effect of Ultraviolet Radiation from an Oxygen Plasma on the Atomic Oxygen-induced Etching of Fluorinated Polymer

  TAGAWA Masahito, YOKOTA Kumiko, KISHIDA Kazuhiro, OKAMOTO Akio, ISHIZAWA Junichiro, MINTON Timothy K

  Mar. 2010, High Perform Polym, 22(2) (2), 213 - 224, English


• 宇宙環境地上試験の高度化について(1)紫外線敏感材料における紫外線照射効果

  横田久美子, 岸田和博, 田川雅人, 石澤淳一郎

  2010, 宇宙科学技術連合講演会講演集(CD-ROM), 54th, ROMBUNNO.2K15, Japanese


• Mechanistic Studies of Atomic Oxygen Reactions with Polymers and Combined Effects with Vacuum Ultraviolet Light

  Masahito Tagawa, Timothy K. Minton

  This article focuses on mechanistic aspects of hyperthermal atomic oxygen reactions with polymers, which are the major contributor to material degradation in low Earth orbit. Due to the importance of well-controlled experiments in the understanding of the reaction mechanisms, ground-based experimental results obtained by a hyperthermal atomic oxygen beam generated by laser detonation facilities are mainly surveyed. Combined effects of atomic oxygen and vacuum ultraviolet (VUV) light on fluorinated polymers are also described. Such combined effects of hyperthermal atomic oxygen and VUV light are important not only from a fundamental point of view but also for engineering purposes (i.e., methodology for ground-based space environmental simulation). The VUV-sensitive polymers, poly(methyl methacrylate), and Teflon-fluorinated ethylene-propylene do not show significant synergistic effects. Instead, the effect of combining atomic oxygen and VUV light produces erosion of the polymer that is the sum of the erosion caused by atomic oxygen and UV light acting individually. The experimental results suggest that material erosion in a complicated space environment may be quantitatively predicted if the erosion yields caused by the individual action of atomic oxygen and VUV light are known.

  MATERIALS RESEARCH SOC, Jan. 2010, MRS BULLETIN, 35(1) (1), 35 - 40, English

  [Refereed]

  Introduction scientific journal


• Protection of diamond-like carbon films from energetic atomic oxygen degradation through Si-doping technology

  Kumiko Yokota, Masahito Tagawa, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka, Julien Fontaine, Michel Belin

  The effect of hyperthermal atomic oxygen (AO) exposure on the surface properties of Si-doped diamond-like carbon (DLC) was investigated. Two types of DLC were tested that contain approximately 10 at% and 20 at% of Si atoms. Surface analytical results of high-resolution x-ray photoelectron spectroscopy using synchrotron radiation (synchrotron radiation photoemission spectroscopy; SR-PES) as well as Rutherford backscattering spectroscopy (RBS) have been used for characterization of the AO-exposed Si-doped DLC. It was identified by SR-PES that a SiO2layer was formed by the hyperthermal AO exposure at the Si-doped DLC surface. RBS data indicates that AO exposure leads to severe thickness loss on the undopedd DLC. In contrast, a SiO2layer formed by the hyperthermal atomic oxygen reaction of Si-doped DLC protects the DLC underneath the SiO2layer © 2009 American Institute of Physics.

  13 Apr. 2009, AIP Conference Proceedings, 1087, 368 - 383


• DEGRADATION OF THERMAL CONTROL MATERIALS IN A SPACE ENVIRONMENT

  TAGAWA Masahito, YOKOTA Kumiko

  08 Oct. 2008, Thermophysical properties, 29, 211 - 213, Japanese


• OS1101 Cell-adhesive properties on the biodegradable materials modified by atom beam

  YOKOTA Kumiko, HIWA Chiaki, TAGAWA Masahito, ADACHI Taiji, NAKAI Yoshikazu

  生体材料表面と細胞の相互作用は材料表面の特性に影響されるということが知られている.本研究では,ポリ乳酸表面に原子状酸素ビームおよび原子状フッ素ビームを照射することで表面改質を行い,マウス骨芽細胞様細胞(MC3T3-E1)のポリ乳酸表面への播種直後の初期細胞接着性および細胞増殖性について検討を行った.材料の表面改質結果は,原子状酸素ビーム照射表面では親水性を示し,原子状フッ素ビーム照射表面は疎水性を示した.その結果,原子状酸素ビームを照射した表面では細胞増殖過程において細胞接着が抑制されることが確認された.

  The Japan Society of Mechanical Engineers, 16 Sep. 2008, M&M材料力学カンファレンス, 2008, "OS1101 - 1"-"OS1101-2", Japanese


• 原子状酸素を照射した水素化ダイヤモンドライクカーボン薄膜の水素分布

  田川雅人, 横田久美子, 北村晃, 松本康司, 吉越章隆, 寺岡有殿

  02 Sep. 2008, 応用物理学会学術講演会講演予稿集, 69th(2) (2), 618, Japanese


• 並進エネルギーアシストCVDによる機能性薄膜の室温反応形成技術

  Masahito Tagawa

  Mar. 2008, 平成18年度学術研究支援事業研究成果報告書, ひょうご科学技術協会、pp59-64, Japanese

  Others


• 超熱酸素原子線による水素化ダイヤモンドライクカーボン薄膜の選択的エッチング

  田川雅人, 横田久美子, 北村晃, 松本康司, 山田倫子, 神田一浩, 新部正人, 吉越章隆, 寺岡有殿, BELIN Michel, FONTAINE Julien

  14 Nov. 2007, 真空に関する連合講演会講演予稿集, 48th, 54, Japanese


• 超熱原子状酸素によるシリコン直接表面酸化反応における運動エネルギーの効果

  田川雅人, 十河千恵, 横田久美子, 吉越章隆, 寺岡有殿

  27 Mar. 2007, 応用物理学関係連合講演会講演予稿集, 54th(2) (2), 790, Japanese


• Reaction of diamond-like carbon film and atomic oxygen in a LEO space environment

  田川雅人, 横田久美子, 松本康司, 北村晃, 山田倫子, 神田一浩, 新部正人, 吉越章隆, 寺岡有殿, BELIN Michel, FONTAINE Julien

  2007, 宇宙科学技術連合講演会講演集(CD-ROM), 51st, 2D04, Japanese


• 水素化DLC薄膜への超熱原子状酸素照射の効果について

  横田久美子, 浅田秀俊, 田川雅人, 大原久典, 中東孝浩, 吉越章隆, 寺岡有殿, MARTIN J‐M, BELIN M

  29 Aug. 2006, 応用物理学会学術講演会講演予稿集, 67th(2) (2), 661, Japanese


• Oxidation of Si(001) with a hyperthermal O-atom beam at room temperature: Suboxide distribution and residual order structure

  TAGAWA Masahito, SOGO Chie, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden, SHIMURA Takayoshi

  27 Mar. 2006, Appl Phys Lett, 88(13) (13), 133512-133512-3, English


• 5eV酸素原子線と超熱窒素分子線併用によるシリコン酸窒化構造の形成

  田川雅人, 横田久美子, 西崎徳晃, 宮階優, 吉越章隆, 寺岡有殿

  22 Mar. 2006, 応用物理学関係連合講演会講演予稿集, 53rd(2) (2), 781, Japanese


• Characteristics of the Formation of Silicon Dioxide by Atomic Oxygen in LEO (3)

  Yokota Kumiko, Tagawa Masahito, Yoshigoe Akitaka, Teraoka Yuden

  The Twenty-second Space Utilization Symposium (January 17-19, 2006: Science Council of Japan, Roppongi, Tokyo, Japan)The oxide film formed on Si(001) in a simulated low Earth orbit (LEO) space environment was analyzed by synchrotron radiation photoelectron spectroscopy (SR-PES). SR-PES results clearly indicated that the amount of suboxides at the Si/SiO2 interface formed in a simulated LEO environment at room temperature was much lower than that formed by an ordinary high-temperature oxidation process.Meeting sponsors: The Science Council of Japan, The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS)(JAXA)

  Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA), Mar. 2006, 宇宙利用シンポジウム = Space Utilization Research: Proceedings of Space Utilization Symposium, (22) (22), Japanese


• 超熱酸素原子・窒素分子ビームを用いたSi(001)極薄酸窒化膜室温形成の試み

  田川雅人, 十河千恵, 宮階優, 横田久美子, 吉越章隆, 寺岡有殿

  07 Sep. 2005, 応用物理学会学術講演会講演予稿集, 66th(2) (2), 612, Japanese


• 超熱原子状酸素ビームにより室温酸化したシリコン酸化膜の表面構造解析

  TAGAWA Masahito, YOKOTA Kumiko, SOGO Chie, HACHIUE Syunsuke, TERAOKA Yuden

  2005, 文部科学省ナノテクノロジー総合支援プロジェクト SPring-8 研究成果報告書, Vol.5 (2005) pp.2-5, Japanese

  Others


• 超熱原子・分子線により室温処理したシリコン酸窒化膜の表面解析,

  TAGAWA Masahito, YOKOTA Kumiko, SOGO Chie, TERAOKA Yuden

  2005, 文部科学省ナノテクノロジー総合支援プロジェクト SPring-8 研究成果報告書, Vol.6 (2005) pp.2-5, Japanese

  Report scientific journal


• 宇宙技術の向上を目指して

  TAGAWA Masahito

  2005, 神戸大学最前線, 25, Japanese

  Others


• 宇宙環境における材料表面科学

  TAGAWA Masahito

  2005, 高温学会誌, Vol.31, No.5, 271-276, Japanese

  [Refereed]

  Introduction scientific journal


• Surface analysis of silicon oxynitride film formed by the hyperthermal atomic beam at room temperature

  TAGAWA Masahito, YOKOTA Kumiko, SOGO Chie, TERAOKA Yuden

  2005, SPring-8 User experiment report, Vol.15, (2005) pp.128, English

  Report scientific journal


• Study on Cell Adhesion Micro-patterning and Control of Cytoskeletal Actin Structure : Application of Surface Modification Using Atomic Beam Exposure

  ADACHI Taiji, KATO Machiko, SATO Katsuya, TAGAWA Masahito

  Cell micro patterning on FEP (tetrafluoroethylene-hexafluoropropylene) substrate was studied by modifying its surface using atomic oxygen beam exposure. Firstly, characteristics of the modified surface and its affinity to the cell adhesion were investigated. Roughness of the modified FEP surface measured by atomic force microscopy increased that resulted in decrease in water wettability. To evaluate change in FEP surface affinity to cells, osteoblastic cells (MC3T3E1) were cultured on pristine and modified FEP surfaces. Cell density and cell adhesive area on the modified surface were larger than those on the pristine surface, which resulted in that the surface modification increased the cell proliferation rate. Secondly, cells were cultured on micro patterned FEP surface modified by the atomic beam exposure with a mesh mask of three different patterns (circle and square dots, and linear pattern). Cells formed an adhesion pattern depending on the designed pattern surface modification. Many cells attached in the vicinity of the boundary between modified and pristine surfaces. In addition, cytoskeletal actin fibers, those are the determinant of cellular shape, were frequently aligned along the boundary.

  The Japanese Association for Crystal Growth (JACG), 31 Jul. 2004, Journal of the Japanese Association of Crystal Growth, 31(2) (2), 78 - 82, Japanese


• LPI法によるナノ形状セラミックスの高感度ガスセンサへの適用

  出来 成人, 水畑 穣, 梶並 昭彦, 大前 伸夫, 田川 雅人, 横田 久美子, 竹内 俊文, 石川 博, 葵 奎千, 前川 享, 前田 浩一, 齊藤 靖弘, 関口 幸成, 小林 哲彦, 木内 正人, 桜井 宏昭, 山中 直樹, 山口 寿一

  Mar. 2004, 地域新生コンソーシアム研究開発事業 地域申請コンソーシアム研究開発 平成15年度成果報告書, 未記入, Japanese

  Others


• 超熱原子状酸素ビームによるSiO₂極薄膜の形成

  十河千恵, 横田久美子, 大前伸夫, 田川雅人, 吉越章隆, 寺岡有殿

  2004, 真空に関する連合講演会講演予稿集, 45th, 26, Japanese


• 私たちの暮らしを守る宇宙技術の向上をめざして

  TAGAWA Masahito

  2004, 平成16年度 第22回神戸大学工学部公開講座, 57-62, Japanese

  [Refereed]

  Others


• 宇宙環境と表面分析

  TAGAWA Masahito

  2004, イオン工学ニュース, 57, 12-13, Japanese

  Introduction scientific journal


• レーザーデトネーションを用いた超高度原子ビームの創成とその光学的応用

  田川 雅人

  2004, 倉田奨学金研究報告, 34, 33-34, Japanese

  Report scientific journal


• Young-Dupie equation

  M Tagawa

  JAPAN SOC TRIBOLOGISTS, 2004, JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS, 49(6) (6), 499 - 500, Japanese

  [Refereed]

  Introduction scientific journal


• Cell Micro-Patterning by Atom Beam Exposure

  Taiji Adachi, Fumiaki Kajita, Katsuya Sato, Koshi Matsumoto, Masahito Tagawa

  This study aimed to develop a new cell micro-patterning method by controlling material surface affinity of the cell using atomic oxygen beam exposure. Surfaces of low-density polyethylene (LDPE) and tetrafluoroethylene-hexafluoropropylene (FEP) were exposed to the atomic oxygen beam. On the LDPE surface, the roughness measured by atomic force microscopy (AFM) did not change much, however, the oxygen concentration on the surface measured by X-ray photoelectron spectroscopy (XPS) significantly increased that resulted in increase in wettability. Contrary to this, on the FEP surface, the oxygen concentration showed no significant change, but roughness of the surface remarkably increased and the wettability decreased. As a result of the surface modification, affinity of the osteoblastic cells on the FEP surface increased, which was also confirmed by increase in the cell area. Finally, cell micro-patterning on the FEP surface was carried out based on difference in the affinity between modified and unmodified surfaces patterned by a masking method.

  01 Dec. 2003, Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 69, 1782 - 1788


• Cell micro-patterning by atomic oxygen exposure

  KAJITA Fumiaki, MATSUMOTO Koushi, SATO Katsuya, TAGAWA Masahito, ADACHI Taiji

  The Japan Society of Mechanical Engineers, 20 Jan. 2003, バイオエンジニアリング講演会講演論文集, 2003(15) (15), 17 - 18, Japanese


• 521 原子ビームを用いた材料表面改質と細胞接着制御(生体・医療材料-I)(生体・医療材料分野の技術開発と将来展望)(オーガナイスドセッション11)

  安達 泰治, 梶田 文昭, 佐藤 克也, 松本 康志, 田川 雅人

  日本材料学会, 2003, 学術講演会講演論文集, 52, 390 - 391, Japanese


• レーザーデトネーション誘起超音速原子ビームを用いた低損傷表面改質技術

  田川 雅人

  2003, 財団法人 ひょうご科学技術協会平成14年度学術研究支援事業 研究成果報告書, 75-79, Japanese

  Others


• Water Adsorption on the LIGA Ni Films and Its Effects on Friction

  BABA Yasuyuki, KINOSHITA Hiroshi, TAGAWA Masahito, UMENO Masataka, OHMAE Nobuo

  日本トライボロジ-学会, 15 May 1999, Journal of Japanese Society of Tribologists, 44(5) (5), 379 - 386, Japanese


• Surface Reaction of a Low-Flux Atomic Oxygen Beam with a Spin-Coated Polymide Film : Synergetic Effect of Atomic Oxygen and Ultraviolet Exposures

  TAGAWA Masahito, SUETOMI Toru, KINOSHITA Hiroshi, UMENO Masataka, OHMAE Nobuo

  Japan Society for Aeronautical and Space Sciences, 04 May 1999, Transactions of the Japan Society for Aeronautical and Space Sciences, 42(135) (135), 40 - 45, English


• Visitor Report at NASA-Jet Propulsion Laboratory

  TAGAWA Masahito

  15 Feb. 1999, トライボロジスト, 44(2) (2), 119 - 120, Japanese


• Atomic oxygen-induced erosion of the polyimide films studied by QCM, AFM, XPS, and contact angle measurements

  GOTOH Keiko, M. Tagawa, K. Yokota, N. Ohmae, H. Kinoshita, M.Umeno, K. Gotoh

  1999, Proceedings of the 6th Japan International SAMPE Symposium and Exhibition, 1147 - 1150, English

  Introduction international proceedings


• スペ-ストライボロジ-の現状と将来

  田川 雅人, 大前 伸夫

  生産技術振興協会, Jan. 1998, 生産と技術, 50(1) (1), 27 - 30, Japanese


• Si-SiO2界面構造の形成とその直接観察 (原子レベルでの結晶成長機構) -- (成長表面と界面構造)

  梅野 正隆, 大前 伸夫, 田川 雅人

  日本結晶成長学会, Oct. 1994, 日本結晶成長学会誌, 21(5) (5), Sp241 - 248, Japanese


• マイクロマシン--マイクロ理工学--マイクロマシンのトライボロジ- (マイクロマシンとマイクロトライボロジ-<特集>)

  大前 伸夫, 田川 雅人

  養賢堂, Jan. 1994, 機械の研究, 46(1) (1), p104 - 107, Japanese


• マイクロトライボロジ-

  大前 伸夫, 田川 雅人

  日本トライボロジ-学会, Jan. 1992, トライボロジスト, 37(1) (1), p10 - 16, Japanese

• 宇宙機の熱設計

  Masahito Tagawa

  Joint editor, 名古屋大学出版会, Feb. 2014, Japanese, abbreviated, ISBN: 9784815807580

  Scholarly book


• 宇宙機の熱設計

  Ohnishi Akira, Sugita Hiroyuki, Tagawa Masahito

  Joint work, 名古屋大学出版会, 2014, Japanese, ISBN: 9784815807580

  Scholarly book


• 新版固体潤滑ハンドブック

  Masahito Tagawa

  Joint work, 養賢堂, Mar. 2010, Japanese

  Scholarly book


• 熱物性ハンドブック

  Masahito Tagawa

  Joint work, 養賢堂, Apr. 2008, Japanese

  Scholarly book


• Enhancement of atomic oxygen-induced erosion of spacecraft polymeric materials by simultaneous ultraviolet exposure

  TAGAWA Masahito, YOKOTA Kumiko, OHMAE Nobuo

  Joint work, Springer, Apr. 2006, English

  Scholarly book


• Atomic oxygen concentration using reflecting mirrors

  TAGAWA Masahito, YOKOTA Kumiko, OHMAE Nobuo, MATSUMOTO Koshi, DOI Hiroaki

  Joint work, Springer, Apr. 2006, English

  Scholarly book


• DLC膜ハンドブック

  TAGAWA Masahito

  Joint work, NTS, Feb. 2006, Japanese

  Scholarly book


• Effect of surface charging on the erosion rate of polyimide under 5 eV atomic oxygen beam exposures

  SEIKYU Shinsuke, MAEDA Ken-ichi, YOKOTA Kumiko, OHMAE Nobuo, TAGAWA Masahito

  Joint work, Elsevier, 2006, English

  Scholarly book


• Polyimide erosion in low Earth orbit space environment

  TAGAWA Masahito, YOKOTA Kumiko

  Joint work, VSP, 2005, English

  Scholarly book

• 惑星高層大気環境模擬のための複合分子線システムの構築とロングノズルの効果について

  大倉僚太, 藤本友介, 清水鉄平, 岩田稔, 木本雄吾, 横田久美子, 田川雅人

  第55日本航空宇宙学会中部・関西支部合同秋季大会, Nov. 2018


• 大気吸入型イオンエンジン放電室内におけるECRプラズマ生成過程の粒子法による数値解析

  白川遼, 臼井英之, 三宅洋平, 田川雅人, 西山和孝

  第55日本航空宇宙学会中部・関西支部合同秋季大会, Nov. 2018


• 超低軌道宇宙環境における高分子材料の劣化原因対する考察とSLATSデータとの比較検討

  藤本友介, 井出航, 大倉僚太, 岩田稔, 土屋佑太, 後藤亜希, 行松和輝, 木本雄吾, 横田久美子, 田川雅人

  第55日本航空宇宙学会中部・関西支部合同秋季大会, Nov. 2018


• 大気吸入型イオンエンジンにおけるECRプラズマ粒子シミュレーション

  白川遼, 臼井英之, 三宅洋平, 田川雅人, 西山和孝

  2018年日本表面真空学会学術講演会, Nov. 2018


• 超低軌道宇宙環境での高分子材料の耐性評価とSLATSデータとの比較検討について

  藤本友介, 井出航, 大倉僚太, 岩田稔, 土屋佑太, 後藤亜希, 行松和輝, 木本雄吾, 横田久美子, 田川雅人

  2018年日本表面真空学会学術講演会, Nov. 2018


• 惑星高層大気シミュレーションのための複合分子線システムの構築とロングノズルの効果

  大倉僚太, 藤本友介, 清水鉄平, 岩田稔, 木本雄吾, 横田久美子, 田川雅人

  2018年日本表面真空学会学術講演会, Nov. 2018


• 超熱原子ビームによる固体表面の濡れ性制御

  田川雅人, 横田久美子

  第39回日本熱物性シンポジウム, Nov. 2018


• 超低軌道宇宙環境模擬のためのワンノズルツービームレーザーデトネーション原子状酸素ビーム装置

  横田久美子, 大倉僚太, 藤本友介, 岩田稔, 田川雅人

  第39回日本熱物性シンポジウム, Nov. 2018


• 大気吸入型イオンエンジン放電室内におけるECRプラズマ生成シミュレーション

  白川遼, 臼井英之, 三宅洋平, 田川雅人, 西山和孝

  第15回宇宙環境シンポジウム, Oct. 2018, 仙台


• ISS材料劣化実験における原子状酸素フルーエンス計測法に関する一考察

  田川雅人藤本友介, 大倉僚太, 白川遼, 井出航, 横田久美子, Kim K. de Groh, Bruce A. Banks

  第15回宇宙環境シンポジウム, Oct. 2018, 仙台


• “宇宙材料劣化研究拠点の活動“

  岩田稔, 田川雅人, 太刀川純孝

  第62回宇宙科学技術連合講演会, Oct. 2018, 久留米市


• “惑星高層大気環境模擬のための複合分子線システムの構築とロングノズルの効果“

  大倉僚太, 藤本友介, 清水鉄平, 岩田稔, 木本雄吾, 横田久美子, 田川雅人

  第62回宇宙科学技術連合講演会, Oct. 2018, 久留米市


• 超低軌道宇宙環境における高分子材料の劣化特性とSLATSデータとの比較検討

  藤本友介, 井出航, 大倉僚太, 岩田稔, 土屋佑太, 後藤亜季, 行松和輝, 木本雄吾, 横田久美子, 田川雅人

  第62回宇宙科学技術連合講演会, Oct. 2018, 久留米市


• 大気吸入型イオンエンジン放電室内におけるECRプラズマ生成シミュレーション

  白川遼, 臼井英之, 三宅洋平, 田川雅人, 西山和孝

  第62回宇宙科学技術連合講演会, Oct. 2018, 超低軌道宇宙環境における高分子材料の劣化特性とSLATSデータとの比較検討


• 宇宙用材料を指向した液晶ポリマーへの原子状酸素照射

  小柴康子, 横田久美子, 西本卓馬, 堀家匠平, 福島達也, 田川雅人, 石田謙司

  第79回応用物理学会秋季学術講演会, Sep. 2018, 名古屋市


• 原子状酸素ビーム照射試験における残留未解離酸素分子の影響

  横田久美子, 北 一貴, 藤本友介, 大倉僚太, 田川雅人

  第79回応用物理学会秋季学術講演会, Sep. 2018, 名古屋市


• 超低軌道環境における中性ガス衝突誘起材料劣化現象メカニズムの解析

  横田久美子, 田川雅人

  第4回超低高度衛星の利用に向けたワークショップ, Sep. 2018, 東京


• 空気吸込式イオンエンシ?ンの実証に向けたエアインテーク数値解析

  小澤宇志, 今村俊介, 西山和孝, 田川雅人, 藤田和央

  第50回流体力学講演会, Jul. 2018, 宮崎


• 超低軌道環境における中性ガス衝突誘起材料劣化現象メカニズムの解析

  横田久美子, 田川雅人

  SLATS報告会, Mar. 2018


• 薄型ピエゾバルブを用いたワンノズルツービム超熱原子線システム

  横田久美子, 清水鉄兵, 大倉僚太, 藤本友介, 北一貴, 徐世傑, 岩田稔, 田川雅人

  第65回応用物理学会春季学術講演会, Mar. 2018


• 研究紹介 ?神戸大学における宇宙環境工学研究2

  大倉僚太, 横田久美子, 田川雅人

  ライト祭, Dec. 2017


• 研究紹介 ?神戸大学における宇宙環境工学研究1

  藤本友介, 横田久美子, 田川雅人

  ライト祭, Dec. 2017


• 超低軌道宇宙環境におけるFEP/Agの劣化メカニズムについて

  藤本友介, 北一貴, 大倉僚太, 岩田稔, 横田久美子, 田川雅人

  第54回日本航空宇宙学会関西中部支部合同講演会, Nov. 2017


• 惑星高層大気環境模擬のための複合分子・原子線実験装置の開発

  大倉僚太, 藤本友介, 北一貴, 岩田稔, Chee Sze Keat, 木本雄吾, 横田久美子, 田川雅人

  第54回日本航空宇宙学会関西中部支部合同講演会, Nov. 2017


• 低軌道環境におけるFEP/Ag熱制御材劣化について

  横田久美子, 大倉僚太, 藤本友介, 北一貴, 田川雅人

  第38回日本熱物性シンポジウム, Nov. 2017


• 惑星高層大気シミュレーションのための複合分子線システムの構築と評価

  大倉僚太, 藤本友介, 北一貴, 岩田稔, 徐世傑, 木本雄吾, 横田久美子, 田川雅人

  第60回宇宙科学技術連合講演会, Oct. 2017


• 模擬超低軌道宇宙環境におけるFEP/Agフィルムの劣化評価について

  藤本友介, 北一貴, 大倉僚太, 岩田稔, 横田久美子, 田川雅人

  第60回宇宙科学技術連合講演会, Oct. 2017


• 宇宙機用熱制御材料における宇宙環境地上模擬研究に関する近年の話題

  横田久美子, 田川雅人

  日本航空宇宙学会関西支部 第463回航空懇談会, Sep. 2017


• 超低軌道宇宙環境におけるFEP/Agフィルムの劣化原因に対する考察

  藤本友介, 北一貴, 大倉僚太, 岩田稔, 横田久美子, 田川雅人

  第14回宇宙環境シンポジウム, Jun. 2017


• 惑星高層大気環境模擬のための複合分子線実験装置の構築と評価について

  大倉僚太, 藤本友介, 北一貴, 岩田稔, Chee Sze Keat, 木本雄吾, 横田久美子, 田川雅人

  第14回宇宙環境シンポジウム, Jun. 2017


• 低軌道宇宙環境耐性をもつ木質炭素化膜の微細構造解析

  畑俊充, 梶本武志, 田川雅人, 小嶋浩嗣

  第15回木質炭化学会研究発表会, Jun. 2017


• 軟X線照射によるフッ素含有DLC膜の膜物性変化

  高松大樹, 神田一浩, 三浦永理, 赤坂大樹, 雑賀章浩, 玉田耕治, 田川雅人, 横田久美子, 古山雄一

  第78回応用物理学会春季学術講演会, Mar. 2017


• レーザー駆動混合ガスプラズマからの極端紫外線放射スペクトル ―混合割合によるスペクトル変化―

  田川雅人, 大平淳貴, 木本雄吾, 西村博明, 横田久美子

  第78回応用物理学会春季学術講演会, Mar. 2017


• 宇宙環境地上試験におけるEUV放射強度の低減

  横田久美子, 大平淳貴, 大藪高詩, 木本雄吾, 西村博明, 田川雅人

  第78回応用物理学会春季学術講演会, Mar. 2017


• 大気吸入イオンエンジンの現状と課題

  安河内 翼, 田川雅人, 横田久美子, 三宅洋平, 臼井英之, 西山和孝

  第57回航空原動機・宇宙推進講演会, Mar. 2017


• 宇宙環境誘起材料劣化に関する最近の話題：劣化原因と複合効果の理解は正しかったのか

  田川雅人

  第330回生存圏シンポジウムプログラム, Jan. 2017


• プラズマシミュレーション援用による大気吸入型イオンエンジンの実験的研究

  安河内翼, 臼井英之, 三宅洋平, 福田雅人, 横田久美子, 田川雅人

  第332回生存圏シンポジウム, Dec. 2016


• 宇宙材料劣化研究拠点による学術研究の活性化と高度な衛星プロジェクト支援

  岩田稔, 田川雅人, 太刀川純孝, 平尾敏雄, 大津志保

  第37回日本熱物性シンポジウム, Nov. 2016


• 火星高層大気環境シミュレーションを目指した超熱混合分子ビーム形成の試み

  横田久美子, 初田光嶺, 田川雅人

  第37回日本熱物性シンポジウム, Nov. 2016


• 変位拡大機構を用いた高速超音速分子線バルブ

  横田久美子, 徐世傑, 田川雅人

  第77回応用物理学会秋季学術講演会, Sep. 2016


• 宇宙材料劣化研究拠点の形成と衛星プロジェクト支援（II）

  岩田稔, 田川雅人, 太刀川純孝, 平尾敏雄, 大津志保

  第60回宇宙科学技術連合講演会, Sep. 2016


• 固体粒子加速器への高出力レーザー応用

  守本郁, 弘中陽一郎, 重森啓介, 佐野孝好, 田川雅人, 北澤幸人, 阿藤敏行

  第60回宇宙科学技術連合講演会, Sep. 2016


• 放電室内電界分布の計算結果を考慮した大気吸入型イオンエンジンの実験的研究

  安河内翼, 臼井英之, 三宅洋平, 福田雅人, 横田久美子, 田川雅人

  第60回宇宙科学技術連合講演会, Sep. 2016


• 超低軌道領域における大気吸入型イオンエンジンの利用と課題

  安河内翼, 臼井英之, 三宅洋平, 福田雅人, 横田久美子, 田川雅人

  第60回宇宙科学技術連合講演会, Sep. 2016


• 原子状酸素誘起材料劣化地上試験に関わる複合効果について

  田川雅人, 横田久美子

  第60回宇宙科学技術連合講演会, Sep. 2016


• 不活性分子同時衝突による原子状酸素誘起材料劣化の加速効果

  北一貴, 山崎勇希, 横田久美子, 田川雅人

  第60回宇宙科学技術連合講演会, Sep. 2016


• Development of solid particle accelerator usig GXII laser system

  Yoichiro Hironaka, Masahito Tagawa, Takayoshi Sano, Kaoru Morimoto, Keisuke Shigemori

  レーザー研シンポジウム, Apr. 2016


• Evaluation of the EUV emission from the sub-LEO space environmental simulation using carbon dioxide laser: FY2015 report

  Masahito Tagawa, Kumiko Yokota, Junki Ohira, Kaoru Morimoto, Yugo Kimoto, Hiroaki Nishimura

  レーザー研シンポジウム, Apr. 2016


• 低軌道宇宙環境耐性をもった木質系炭素膜の微細構造

  畑 俊充, 梶本武志, 田川雅人, 小嶋浩嗣

  第66回日本木材学会大会, Mar. 2016


• 超低高度宇宙環境における原子状酸素誘起材料劣化現象における窒素分子同時衝突効果の定量化

  横田久美子, 北一貴, 山?勇希, 田川雅人

  第63回応用物理学会春季学術講演会, Mar. 2016


• 高出力レーザーを用いた非破壊固体粒子加速法の開発

  守本 郁, 弘中陽一郎, 重森啓介, 佐野孝好, 田川雅人, 北澤幸人, 阿藤敏行

  第63回応用物理学会春季学術講演会, Mar. 2016


• 分子流入を考慮した大気吸入型イオンエンジンの中性粒子シミュレーション

  安河内 翼, 臼井英之, 三宅洋平, 川口伸一郎, 福田雅人, 横田久美子, 田川雅人

  第63回応用物理学会春季学術講演会, Mar. 2016


• 高出力レーザーを用いた固体粒子加速法の開発

  守本 郁, 弘中陽一郎, 重森啓介, 佐野孝好, 田川雅人, 北澤幸人, 阿藤敏行

  平成27年度衝撃波シンポジウム, Mar. 2016


• 宇宙環境工学の観点から見たSLATSへの期待

  田川雅人, 井出健太, 山崎勇希, 北一貴, 横田久美子

  第3回超低高度衛星利用に向けてのワークショップ, Feb. 2016


• スペースデブリ問題に関するトピックス -微小デブリ研究と対策-

  松本晴久, 奥平修, 神谷浩紀, 花田俊也, 東出真澄, 赤星保浩, 仁田工美, 弘中陽一郎, 田川雅人, 北澤幸人

  テクノ・シンポジウム名大, Feb. 2016


• 宇宙デブリの衝突評価技術

  北澤幸人, 弘中陽一郎, 大平淳貴, 佐野孝好, 重森啓介, 田川雅人

  平成27年度光ビームプラットフォーム報告会, Jan. 2016


• 宇宙材料劣化研究拠点の形成 〜衛星プロジェクト支援のこれまでとこれから〜

  岩田稔, 田川雅人, 太刀川純孝, 平尾敏雄, 大津志保

  第31回宇宙構造材料シンポジウム, Jan. 2016


• プラズマシミュレーションを用いたABIE放電室内における中性粒子吸入を考慮したプラズマ生成解析

  川口 伸一郎, 臼井 英之, 三宅 洋平, 安河内 翼, 福田 雅人, YOKOTA KUMIKO, TAGAWA MASAHITO

  第12回宇宙環境シンポジウム, Nov. 2015, Japanese, Kitakyushu, Domestic conference

  Oral presentation


• プラズマシミュレーション援用による大気吸入型イオンエンジン開発に向けたプラズマ解析と実機検証

  川口 伸一郎, 臼井 英之, 三宅 洋平, 安河内 翼, YOKOTA KUMIKO, TAGAWA MASAHITO

  第58回宇宙科学技術連合講演会, Oct. 2015, Japanese, Kagoshima, Domestic conference

  Poster presentation


• Oxidation of titanium atoms in DLC films by hyperthermal atomic oxygen beam relevance to space environmental effect in LEO

  Masahito Tagawa, Akimine Hatsuda, Daiki Watanabe, Kumiko Yokota

  16th European Conference on Application of Surface and Interface Analysis,, Sep. 2015, English, Granada, Spain., International conference

  Poster presentation


• Energy dependence on oxidation of Si-containing polyimide by hyperthermal atomic oxygen collisions

  Kumiko Yokota, Daiki Watanabe, Akimine Hatsuda, Masahito Tagawa

  16th European Conference on Application of Surface and Interface Analysis,, Sep. 2015, English, Granada, Spain., International conference

  Poster presentation


• Property of hyperthermal CO2 beam formed by a laser-detonation facility for space environmental effect studies in upper Martian atmosphere

  Masahito Tagawa, Akimine Hatsuda, Kumiko Yokota

  13th International Conference on Laser Ablation, Aug. 2015, English, Cairns, Australia, International conference

  Poster presentation


• Laser-detonation facility for acceleration of gaseous materials: Etching and deposition of solid materials

  Kumiko Yokota, Kenta Ide, Junki Ohira, Yuki Yamazaki, Kaoru Morimoto, Hidetoshi Asada, Masahito Tagawa

  13th International Conference on Laser Ablation, Aug. 2015, English, Cairns, Australia, International conference

  Poster presentation


• Three Dimensional Particle-In-Cell Simulation for the Development of Air Breathing Ion Engine

  川口 伸一郎, 臼井 英之, 三宅 洋平, 安河内 翼, 福田 雅人, YOKOTA KUMIKO, TAGAWA MASAHITO

  Joint Conference of 30th International Symposium on Space Technology and Science, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Jul. 2015, English, Kobe, International conference

  Poster presentation


• Numerical Simulation of ECR Plasma in Air Breathing Ion engine (ABIE): Neutral Gas Density Distribution and ECR Plasma Formation

  Yasukochi Tsubasa, Usui Hideyuki, Miyake Yohei, Kawaguchi Shin-ichirou, Fukuda Masato, Yokota Kumiko, Tagawa Masahito

  Joint Conference of 30th International Symposium on Space Technology and Science, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Jul. 2015, English, Kobe, International conference

  Poster presentation


• Laser-detonation beam facilities for sub-LEO material erosion studies

  Kumiko Yokota, Kenta Ide, Yuki Yamasaki, Akimine Hatsuda, Kaoru Morimoto, Masahito Tagawa

  13th International Symposium on Materials in the Space Environment, Jun. 2015, English, ONERA, Pau, France, International conference

  Poster presentation


• Effect of high-energy inert gas collisions on the atomic oxygen-induced polymer erosion

  Masahito Tagawa, Kenta Ide, Yuki Yamasaki, Daiki Watanabe, Kumiko Yokota

  13th International Symposium on Materials in the Space Environment, Jun. 2015, English, ONERA, Pau, France, International conference

  Oral presentation


• Collision-induced oxidation of Si atoms embedded in carbon-based material

  Masahito Tagawa, Daiki Watanabe, Yuichi Furuyama, Kazuhiro Kanda, Akitaka Yoshigoe, Yuden Teraoka, Koji Matsumoto, Kumiko Yokota

  13th International Symposium on Materials in the Space Environment, Jun. 2015, English, ONERA, Pau, France, International conference

  Poster presentation


• 超低軌道宇宙環境模擬のためのレーザーデトネーションビーム装置

  Yokota Kumiko, Ide Kenta, Ohira Junki, Watanabe Daiki, Yamasaki Yuki, Hatsuda Akimine, Morimoto Iku, Tagawa Masahito

  応用物理学会 第62回応用物理学会春季学術講演会, Mar. 2015, Japanese, 平塚市, Domestic conference

  Oral presentation


• Si-ドープ木質系DLC被膜による低軌道宇宙環境耐性の向上

  Hata Toshimitsu, Tagawa Masahito, Kojima Hirotsugu, Kajimoto Takeshi

  京都大学生存圏研究所 第275回生存圏ミッションシンポジウム, Feb. 2015, Japanese, 宇治市, Domestic conference

  Oral presentation


• 原子状酸素照射によるカーボンナノチューブ電界放出カソードへの影響と対策評価

  Shimada Atsuko, Imoto Shin, Yuasa Naoki, Ohkawa Yasushi, Matsumoto Koji, Tagawa Masahito, Yamagiwa Yoshiki

  宇宙航空研究開発機構 平成26年度宇宙輸送シンポジウム, Jan. 2015, Japanese, 相模原市, Domestic conference

  Oral presentation


• Si含有水素化DLC膜への原子状酸素照射の影響

  Kidena Kengo, Niibe Masahito, Yokota Kumiko, Tagawa Masahito, Furuyama Yuichi, Komatsu Keiji, Saito Hidetishi, Kanda Koichi

  日本放射光学会 第28回日本放射光学会年会 放射光科学合同シンポジウム, Jan. 2015, Japanese, 草津市, Domestic conference

  Oral presentation


• 研究紹介 -宇宙環境工学-

  Tagawa Masahito

  日本航空宇宙学会 2014ライト祭, Dec. 2014, Japanese, 大阪市, Domestic conference

  Oral presentation


• Si, Ti添加ダイヤモンドライクカーボン膜表面酸化反応における原子状酸素衝突エネルギーの影響

  Watanabe Daiki, Hatsuda Akimine, Furuyama Yuichi, Kanda Kazuhiro, Yoshigoe Akitaka, Teraoka Yuden, Yokota Kumiko, Tagawa Masahito

  宇宙航空研究開発機構 第11回宇宙環境シンポジウム, Dec. 2014, Japanese, 大阪市, Domestic conference

  Oral presentation


• 3次元PICシミュレーションを用いた大気吸入型イオンエンジン放電室内部におけるプラズマ生成解析

  KAWAGUCHI Shinichiro, USUI Hideyuki, MIYAKE Yohei, YASUKOCHI Tsubasa, FUKUDA Masato, YOKOTA Kumiko, TAGAWA Masato

  第11回宇宙環境シンポジウム, Dec. 2014, Japanese, Osaka, Domestic conference

  Oral presentation


• 低軌道宇宙環境地上模擬試験の高度化について

  Tagawa Masahito, Yokota Kumiko

  日本航空宇宙学会 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, 長崎市, Domestic conference

  Oral presentation


• 超低地球軌道環境シミュレーションのためのAr・O2混合プラズマの分光評価

  Ohira Junki, Yokota Kumiko, Tagawa Masahito

  日本真空学会 第55回真空に関する連合講演会, Nov. 2014, Japanese, 大阪市, Domestic conference

  Oral presentation


• 超低高度大気環境による材料劣化現象について

  Yokota Kumiko, Yamasaki Yuki, Hatsuda Akimine, Ide Kenta, Watanabe Daiki, Tagawa Masahito

  日本航空宇宙学会 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, 長崎市, Domestic conference

  Oral presentation


• 火星高層大気と宇宙機との相互作用に関する研究(1) レーザーデトネーション法による超熱二酸化炭素ビーム形成

  Hatsuda Akimine, Yokota Kumiko, Tagawa Masahito

  日本航空宇宙学会 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, 長崎市, Domestic conference

  Oral presentation


• 衛星搭載用水晶振動子を用いた非回収軌道上材料曝露試験と地上キャリブレーション

  Yokota Kumiko, Ide Kenta, Yamasaki Yuki, Nishiyama Kazutaka, Tagawa Masahito

  日本熱物性学会 第35回日本熱物性シンポジウム, Nov. 2014, Japanese, 東京都, Domestic conference

  Oral presentation


• 宇宙機搭載用QCMを用いた宇宙環境誘起材料劣化に関する地上対照試験法

  Yamasaki Yuki, Ide Kenta, Nishiyama Kazutaka, Yokota Kumiko, Tagawa Masahito

  日本航空宇宙学会 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, 長崎市, Domestic conference

  Oral presentation


• カーボンナノチューブ電界放出カソードにおける原子状酸素対策の有効性評価

  Shimada Atsuko, Imoto Shin, Ohkawa Yasushi, Matsumoto Koji, Tagawa Masahito, Yamagiwa Yoshiki

  日本航空宇宙学会 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, 長崎市, Domestic conference

  Oral presentation


• Si, Ti添加DLC膜表面酸化反応における原子状酸素衝突エネルギーの影響

  Watanabe Daiki, Yokota Kumiko, Tagawa Masahito

  日本真空学会 第55回真空に関する連合講演会, Nov. 2014, Japanese, 大阪市, Domestic conference

  Oral presentation


• 3次元プラズマシミュレーションをもちいた大気吸入型イオンエンジン開発のためのECRプラズマ生成解析

  KAWAGUCHI Shinichiro, USUI Hideyuki, MIYAKE Yohei, YOKOTA Kumiko, TAGAWA Masato, YASUKOCHI Tsubasa

  第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, Nagasaki, Domestic conference

  Oral presentation


• Use of space-qualified quartz crystal microbalance for non-retrieval material tests in space

  Ide Kenta, Yamasaki Yuki, Nishiyama Kazutaka, Tagawa Masahito, Yokota Kumiko

  The 7th Vacuum and Surface Sciences Conference of Asia and Australia, Oct. 2014, English, Hsinchu,Taiwan, International conference

  Oral presentation


• surface interactions in a complicated space environment for future spacecraft development

  Yokota Kumiko, Tagawa Masahito

  The 7th Vacuum and Surface Sciences Conference of Asia and Australia, Oct. 2014, English, Hsinchu,Taiwan, International conference

  Oral presentation


• Hyperthermal collision of O-atom on metal-doped diamond-like carbon films: effect of collision energy on the formation of protective oxide films

  Watanabe Daiki, Hatsuda Akimine, Furuyama Yuichi, Kanda Kazuhiro, Yoshigoe Akitaka, Teraoka Yuden, Yokota Kumiko, Tagawa Masahito

  The 7th Vacuum and Surface Sciences Conference of Asia and Australia, Oct. 2014, English, Hsinchu,Taiwan, International conference

  Oral presentation


• Extreme ultraviolet emission from a laser-driven mixed gas plasma relevance to sub-low Earth orbit space environmental effect studies

  Ohira Junki, Oyabu Takashi, Kimoto Yugo, Nishimura Hiroaki, Yokota Kumiko, Tagawa Masahito

  The 7th Vacuum and Surface Sciences Conference of Asia and Australia, Oct. 2014, English, Hsinchu,Taiwan, International conference

  Oral presentation


• 高出力レーザーによる固体粒子加速

  Hironaka Yoichiro, Ohira Junki, Sano Takayoshi, Shigemori Keisuke, Tagawa Masahito, Kitazawa Yukihito

  応用物理学会 第75回応用物理学会秋季学術講演会, Sep. 2014, Japanese, 札幌市, Domestic conference

  Oral presentation


• 火星高層大気シミュレーションのための超熱二酸化炭素ビーム形成

  Hatsuda Akimine, Yokota Kumiko, Tagawa Masahito

  応用物理学会 第75回応用物理学会秋季学術講演会, Sep. 2014, Japanese, 札幌市, Domestic conference

  Oral presentation


• 宇宙材料分野でのビーム表面反応研究の必要性

  Tagawa Masahito

  応用物理学会 第75回応用物理学会秋季学術講演会, Sep. 2014, Japanese, 札幌市, Domestic conference

  Oral presentation


• 宇宙機搭載用水晶振動子微小天秤による軌道上材料劣化評価と地上キャリブレーション

  Yokota Kumiko, Ushioda Yosuke, Ide Kenta, Yamasaki Yuki, Nishiyama Kazutaka, Tagawa Masahito

  応用物理学会 第75回応用物理学会秋季学術講演会, Sep. 2014, Japanese, 札幌市, Domestic conference

  Oral presentation


• Si含有DLC膜の原子状酸素照射効果

  Kidena Kengo, Niibe Masahito, Yokota Kumiko, Tagawa Masahito, Furuyama Yuichi, Komatsu Keiji, Saito Hidetoshi, Kanda Kazuhiro

  応用物理学会 第75回応用物理学会秋季学術講演会, Sep. 2014, Japanese, 札幌市, Domestic conference

  Oral presentation


• Protection of materials from O-atom collision in low Earth orbit using thin oxide film grown in space

  Yokota Kumiko, Yoshigoe Akitaka, Teraoka Yuden, Kanda Kazuhiro, Furuyama Yuichi, Matsumoto Koji, Tagawa Masahito

  13th European Vacuum Conference, Sep. 2014, English, Aveiro,Portugal, International conference

  Poster presentation


• Formation of ultra-thin oxide film at Si(001) by well-characterized hyperthermal broad oxygen atom beam exposed at room temperature

  Tagawa Masahito, Yokota Kumiko, Yoshigoe Akitaka, Teraoka Yuden

  13th European Vacuum Conference, Sep. 2014, English, Aveiro,Portugal, International conference

  Poster presentation


• Reduction of extreme ultraviolet emission from laser-induced oxygen plasma for atom-surface interaction studies in a simulated space environment

  Tagawa Masahito, Ohira Junki, Kimoto Yugo, Nishimura Hiroaki, Yokota Kumiko

  30th European Conference on Surface Science, Aug. 2014, English, Antalya,Turkey, International conference

  Poster presentation


• Ground-based neutral gas environment simulation related to material degradation phenomena in the orbital altitudes of 200-500 km

  Tagawa Masahito, Oyabu Takashi, Ohira Junki, Watanabe Daiki, Yamasaki Yuki, Yokota Kumiko

  COSPAR Scientific Assembly, Aug. 2014, English, Moscow,Russia, International conference

  [Invited]

  Invited oral presentation


• Formation of protective oxide film with self-healing capability on metal-doped diamond-like carbon films using hyperthermal O-atom collision in LEO space environment

  Yokota Kumiko, Yamazaki Yuki, Hatsuda Akimine, Watanabe Daiki, Tagawa Masahito

  30th European Conference on Surface Science, Aug. 2014, English, Antalya,Turkey, International conference

  Poster presentation


• Extreme ultraviolet emission from laser-induced plasma relevance to neutral gas environment simulation in LEO

  Tagawa Masahito, Ohira Junki, Watanabe Daiki, Kimoto Yugo, Nishimura Hiroaki, Yokota Kumiko

  COSPAR Scientific Assembly, Aug. 2014, English, Moscow,Russia, International conference

  Oral presentation


• Atomic oxygen beam irradiation effect on the Si-doped hydrogenated DLC film

  Kidena Kengo, Endo Minami, Takamatsu Hiroki, Imai Ryo, Niibe Masahito, Yokota Kumiko, Tagawa Masahito, Kanda Kazuhiro

  International Union of Materials Research Societies, Aug. 2014, English, Fukuoka,Japan, International conference

  Oral presentation


• Atomic oxygen beam irradiation effect on the Si-doped DLC film

  Kidena Kengo, Endo Minami, Imai Ryo, Niibe Masahito, Yokota Kumiko, Tagawa Masahito, Kanda Kazuhiro

  The 15th IUMRS-International Conference in Asia, Aug. 2014, English, Fukuoka,Japan, International conference

  Oral presentation


• Wood-based, diamond-like carbon for improved resistance against atomic oxygen

  Kajimoto Takeshi, Hata Toshimitsu, Tagawa Masahito, Kojima Hirotsugu, Hayakawa Hajime

  11th International Conference on Protection of Materials and Structures from Space Environment, May 2014, English, Lijiang,China, International conference

  Oral presentation


• 低軌道宇宙環境模擬用レーザーデトネーション型原子状酸素発生装置から発生する極端紫外線の評価とその応用に関する研究

  Tagawa Masahito, Yokota Kumiko, Ohira Junki, Kimoto Yugo, Nishimura Hiroaki

  大阪大学レーザー研シンポジウム2014, Apr. 2014, Japanese, 吹田市, Domestic conference

  Oral presentation


• 導電性木質炭素化物の低軌道宇宙環境耐性向上に関する研究

  Masahito Tagawa, Tishimitsu Hata, Hirotsugu Kojima, Takeshi Kajimoto

  生存圏ミッションシンポジウム, Mar. 2014, Japanese, 京都大学, Uji, abbreviated, Domestic conference

  Oral presentation


• レーザー誘起超音速混合原子ビーム法を用いた酸素原子の電子衝撃イオン化確率測定

  Kumiko Yokota, Takashi Oyabu, Shigeru Yasuda, Masahito Tagawa

  第60回応用物理学会春季学術講演会, Mar. 2014, Japanese, JSAP, Yokohama, abbreviated, Domestic conference

  Oral presentation


• 9eV窒素・アルゴン分子衝突によるフッ素系高分子材料劣化現象―地上実験結果と宇宙実験データの比較―

  Masahito Tagawa, Shinji Fujimoto, Shigeru Yasuda, Kumiko Yokota

  第60回応用物理学会春季学術講演会, Mar. 2014, Japanese, JSAP, Yokohama, abbreviated, Domestic conference

  Oral presentation


• 衝突誘起酸化反応におけるSi酸化プロセスのエネルギー依存性

  Masahito Tagawa, Kumiko Yokota, Akitaka Yoshigoe, Yuden Teraoka

  JAXA研究開発本部宇宙材料勉強会, Jan. 2014, Japanese, JAXA, Tsukuba, abbreviated, Domestic conference

  Public discourse


• 非回収軌道上試験を目指した国産宇宙用QCMの特性と地上キャリブレーション法

  Kenta Ide, Yuki Yamazaki, Yosuke Ushioda, Kazutaka Nishiyma, Kumiko Yokota, MasahitoTagawa

  第10回宇宙環境シンポジウム, Dec. 2013, Japanese, JAXA, Tokyo, abbreviated, Domestic conference

  Oral presentation


• 大気吸入型イオンエンジン放電室内におけるプラズマ生成シミュレーション

  Takahito Motoyama, Hideyuki Usui, Yohei Miyake, Shinichiro Kawaguchi, Kumiko Yokota, Masahito Tagawa

  第10回宇宙環境シンポジウム, Dec. 2013, Japanese, JAXA, Tokyo, abbreviated, Domestic conference

  Oral presentation


• 低軌道宇宙環境におけるOSR用Ag/FEP劣化に対する窒素分子衝突の影響

  Kumiko Yokota, Daiki Watanabe, Masahito Tagawa

  第34回日本熱物性シンポジウム,, Nov. 2013, Japanese, JSTP, Toyama, abbreviated, Domestic conference

  Oral presentation


• Ti含有DLC膜の原子状酸素照射への耐性評価

  Kengo Kidena, Minami Endo, Ryo Imai, Masahito Niibe, Kumiko Yokota, Masahito Tagawa, Yuichi Furuyama, Keishi Kobayashi, Hidetoshi Saito, Kazuhiro Kanda

  NewSUBARU・立命館SRセンター合同シンポジウム2013, Nov. 2013, Japanese, 兵庫県立大学, Kyoto, abbreviated, Domestic conference

  Oral presentation


• A Synchrotron Radiation Photoelectron Spectroscopic Study on the Oxidation Reaction of Si by O-atom with Collision Energies between 2 to 9 eV

  Kumiko Yokota, Masahito Tagawa, Akitaka Yoshigoe, Yuden Teraoka

  PSA-13, Nov. 2013, English, PSA, Okinawa, abbreviated, International conference

  Poster presentation


• 超低軌道環境を模擬するための中性アルゴンガスのフラックス測定

  Masahito Tagawa, Daiki Watanabe, Kumiko Yokota

  第57回宇宙科学技術連合講演会, Oct. 2013, Japanese, JSASS, Yonago, abbreviated, Domestic conference

  Oral presentation


• 原子状酸素照射によるカーボンナノチューブ電界放出カソードへの影響評価

  Atsuko Shimada, Yoshinobu Tanaka, Yasushi Ohkawa, Koji Matsumoto, Masahito Tagawa, Shin Matsui, Yoshiki Yamagiwa

  第57回宇宙科学技術連合講演会, Oct. 2013, Japanese, JSASS, Yonago, abbreviated, Domestic conference

  Oral presentation


• 原子状酸素及びアルゴン混合ビームによるSLATS/MDM地上対照加速試験

  Daiki Watanabe, Takashi Oyabu, Kumiko Yokota, Masahito Tagawa

  第57回宇宙科学技術連合講演会, Oct. 2013, Japanese, JSASS, Yonago, abbreviated, Domestic conference

  Oral presentation


• 地上実験装置を用いた宇宙環境シミュレーションとトライボマテリアル影響評価

  Masahito Tagawa, Kumiko Yokota

  トライボロジー懇談会, Sep. 2013, Japanese, トライボロジー学会, Nagoya, abbreviated, Domestic conference

  [Invited]

  Invited oral presentation


• 原子状酸素照射によるTi含有DLC膜の表面構造変化

  Kengo Kidena, Minami Endo, Ryo Imai, Masahito Niibe, Kumiko Yokota, Masahito Tagawa, Yuichi Furuyama, Kazuhiro Kanada

  第74回応用物理学会秋季学術講演会, Sep. 2013, Japanese, JSAP, Kyoto, abbreviated, Domestic conference

  Oral presentation


• 原子状酸素照射によるSi含有DLC膜への影響

  Minami Endo, Kengo Kidena, Ryo Imai, Msahito Niibe, Kumiko Yokota, Masahito Tagawa, Yuichi Furuyama, Kazuhiro Kanda

  第74回応用物理学会秋季学術講演会, Sep. 2013, Japanese, JSAP, Kyoto, abbreviated, Domestic conference

  Oral presentation


• 巨大フレアにより発生する軟X線の産業素材・生物に対する影響

  Ryo Imai, Masahito Niibe, Kazuhiro Kanda, Masahito Tagawa, Norimasa Kobayashi

  第6回兵庫県立大学シンポジウム, Sep. 2013, Japanese, 兵庫県立大学, Kobe, abbreviated, Domestic conference

  Oral presentation


• レーザー駆動酸素プラズマからの極端紫外線分光の試み

  Masahito Tagawa, Kumiko Yokota, Hiroyuki Shimamura, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  第74回応用物理学会秋季学術講演会,, Sep. 2013, Japanese, JSAP, Kyoto, abbreviated, Domestic conference

  Oral presentation


• レーザー駆動混合ガスプラズマからの極端紫外線放射スペクトル

  Junki Ohira, Takashi Oyabu, Yugo Kimoto, Hiroaki Nishimura, Kumiko Yokota, Masahito Tagawa

  第74回応用物理学会秋季学術講演会, Sep. 2013, Japanese, JSAP, Kyoto, abbreviated, Domestic conference

  Oral presentation


• Use of laser-induced plasmas for gas-surface interaction studies on Earth observation satellites

  Masahito Tagawa, Kumiko Yokota

  International Conference on Research and Applications of Plasmas, Sep. 2013, English, Warsow/Poland, abbreviated, International conference

  Poster presentation


• Influence of 9 eV collision of chemically inert molecules on fluorinated polymer erosion in sub-low earth orbit

  Kumiko Yokota, Masahito Tagawa, Koji Matsumoto, Yuichi Furuyama, Akira Kitamura, Kazuhiro Kanda, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  19th International Vacuum Congress,, Sep. 2013, English, EVS, Paris/France, abbreviated, International conference

  Poster presentation


• Influence of 5 eV collision of O-atoms on material erosions in low earth orbit space environment

  Masahito Tagawa, Kumiko Yokota

  19th International Vacuum Congress,, Sep. 2013, English, EVS, Paris/France, abbreviated, International conference

  Poster presentation


• An attempt to form multiple-composition hyperthermal atomic beams by a laser- induced plasma for planetary environmental studies

  Kumiko Yokota, Daiki Watanabe, Junki Ohira, Takashi Oyabu, Masahito Tagawa

  International Conference on Research and Applications of Plasmas, Sep. 2013, English, Warsow/Poland, abbreviated, International conference

  Poster presentation


• Microwave Plasma Simulation for the Development of Air Breathing Ion Engine

  Takahito Motoyama, Hideyuki Usui, Yohei Miyake, Akihiko Hashimoto, Masahito Tagawa, Kumiko Yokota

  The 11th International School Symposium for Space Simulations, Aug. 2013, English, abbreviated, International conference

  Oral presentation


• 宇宙環境下における衛星材料劣化現象

  Masahito Tagawa

  放射線トピックス講演会, Jul. 2013, Japanese, 岡山理科大学, abbreviated, Domestic conference

  Public discourse


• Synergistic effect of atomic oxygen and vacuum ultraviolet on polymeric materials at various temperatures

  Yosuke Ushioda, Takaho Tsuboi, Kenta Ide, Masahito Tagawa, Kumiko Yokota, Akio Okamoto

  The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conference

  Oral presentation


• Sub-low Earth orbit neutral gas environment simulation using laser detonation beam source

  Takashi Ohyabu, Shigeru Yasuda, Masahito Tagawa, Kumiko Yokota

  The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conference

  Oral presentation


• Microwave plasma simulation for the development of air breathing ion engine

  Takahito Motoyama, Hideyuki Usui, Yohei Miyake, Kumiko Yokota, Masahito Tagawa

  The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conference

  Oral presentation


• Impact of high-energy collision of inert gas on the material degradation in space environment -Erosion properties in the hyperthermal multiple composition beams-

  Masahito Tagawa, Takashi Ohyabu, Shigeru Yasuda, Kumiko Yokota, Akio Okamoto

  The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conference

  Oral presentation


• Impact of high-energy collision of inert gas on the material degradation in space environment -Comparison of the ground-based data and MISSE-2 analysis-,

  Kumiko Yokota, Takashi Ohyabu, Shigeru Yasuda, Masahito Tagawa

  The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conference

  Oral presentation


• A ground-based simulation study for FEP erosion on the SLATS MDM mission

  Shinji Fujimoto, Shigeru Yasuda, Daiki Watanabe, Kumiko Yokota, Masahito Tagawa, Yugo Kimoto, Junichiro Ishizawa

  The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conference

  Oral presentation


• 低軌道宇宙環境模擬用レーザーデトネーション型原子状酸素発生装置から発生する極端紫外線の評価とその応用に関する研究

  Masahito Tagawa, Kumiko Yokota, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  レーザー研シンポジウム2013, May 2013, Japanese, ILE, Osaka University, Suita, abbreviated, Domestic conference

  Oral presentation


• 低軌道宇宙環境における高分子劣化現象とその評価

  Masahito Tagawa, Kumiko Yokota

  第62回高分子年次大会, May 2013, Japanese, 日本高分子学会, Kyoto, abbreviated, Domestic conference

  [Invited]

  Invited oral presentation


• 宇宙環境地上シミュレーション分野における高出力レーザーの利用と期待

  Masahito Tagawa, Kumiko Yokota

  レーザー研シンポジウム2013, May 2013, Japanese, ILE, Osaka University, Suita, abbreviated, Domestic conference

  Invited oral presentation


• Hyperthermal atomic oxygen beam irradiation effect on the Ti-containing DLC film

  Kazuhiro Kanda, Kazuhiro Fukuda, Ryo Imai, Masahito Niibe, Sinya Fujimoto, Kumiko Yokota, Masahito Tagawa

  New Diamond and Nanocarbon Conference, 2013, English, Singapole, abbreviated, International conference

  Poster presentation


• 原子状酸素照射による木質炭素化物の構造変化の解明

  Takeshi Kajimoto, Toshimitu Hata, Masahito Tagawa, Hirotsugu Kojima

  第37回炭素材料学会, Dec. 2010, Japanese, 炭素学会, 姫路, Domestic conference

  Oral presentation


• ATOX-related researches at Kobe University

  Masahito Tagawa

  ESTEC QEM Seminar, Nov. 2010, English, European Space Agency, Noordwijk, International conference

  [Invited]

  Invited oral presentation


• フッ素系高分子の原子状酸素誘起エロージョンにおける非線形エネルギー依存性

  Masahito Tagawa, Kazuhiro Kishida, Kumiko Yokota, Akira Okamoato

  第7回宇宙環境シンポジウム, Oct. 2010, Japanese, 宇宙航空研究機構, 東京, Domestic conference

  Oral presentation


• 宇宙環境誘起材料劣化に及ぼす不活性分子衝突の効果

  Masahito Tagawa, Kumiko Yokota, Akira Okamoato

  第71回応用物理学会学術講演会, Sep. 2010, Japanese, 応用物理学会, 長崎, Domestic conference

  Oral presentation


• 宇宙環境誘起材料劣化に及ぼす原子状酸素と真空紫外線の複合効果

  Kumiko Yokota, Masahito Tagawa, Akira Okamoato

  第71回応用物理学会学術講演会, Sep. 2010, Japanese, 応用物理学会, 長崎, Domestic conference

  Oral presentation


• 宇宙環境地上試験の高度化について(2) 原子状酸素照射時にレーザープラズマから放射される極端紫外線スペクトル計測の試み

  Masahito Tagawa, Kazuhiro Kishida, Akira Mizutani, Kumiko Yokota, Hiroyuki Shimamurra, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  第54回宇宙科学技術連合講演会, Sep. 2010, Japanese, 日本航空宇宙学会, 静岡, Domestic conference

  Oral presentation


• 宇宙環境地上試験の高度化について(1) 紫外線敏感材料における紫外線照射効果"

  Kumiko Yokota, Kazuhiro Kishida, Masahito Tagawa, Jun-ichiro Ishizawa

  第54回宇宙科学技術連合講演会, Sep. 2010, Japanese, 日本航空宇宙学会, 静岡, Domestic conference

  Oral presentation


• 低軌道宇宙環境模擬用レーザーデトネーション型原子状酸素発生装置から発生する極端紫外線の評価とその応用に関する研究

  Masahito Tagawa, Kumiko Yokota, Mayuko Koga, Hiroaki Nishimura

  レーザー研シンポジウム2010, May 2010, Japanese, 大阪大学, 吹田, Domestic conference

  Oral presentation


• 宇宙用木質材料の耐腐食性の向上

  Takeshi Kajimoto, Toshimitu Hata, Masahito Tagawa, Hirotsugu Kojima, Hajime Hayakawa, Hiroshi Yamakawa, Yoshikatu Ueda

  第8回木質炭化学会大会, May 2010, Japanese, 日本木質学会, 東京, Domestic conference

  Oral presentation


• 軟X線照射によるDLC膜からの水素脱離過程

  kazuhiro kanda, Masahito Tagawa, Kumiko Yokota, Mayumi Tode, Yuden Teraoka, Shinji Mayumi

  先端技術セミナー2010, Mar. 2010, Japanese, 兵庫県立大学, 姫路市, Domestic conference

  Oral presentation


• 高水素化DLC膜への真空紫外線照射効果

  Kumiko Yokota, Masahito Tagawa, Yuichi Furuyama, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  第57回応用物理学関係連合講演会, Mar. 2010, Japanese, 応用物理学会, 平塚市, Domestic conference

  Oral presentation


• 高水素化DLC膜からの水素脱離に対する表面金属酸化膜の効果

  Masahito Tagawa, Kumiko Yokota, Yuichi Furuyama, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  第57回応用物理学関係連合講演会, Mar. 2010, Japanese, 応用物理学会, 平塚市, Domestic conference

  Oral presentation


• Arのマイクロ波放電フロー中でのテトラメチルシランの分解を用いた硬質a-SiCx膜の形成(2) 局所構造解析

  Akira Wada, Takeshi Ohgaki, Masahito Niibe, Masahito Tagawa, Hidetoshi Saito, Kazuhiro Kanda, Haruhiko Ito

  第57回応用物理学関係連合講演会, Mar. 2010, Japanese, 応用物理学会, 平塚市, Domestic conference

  Oral presentation


• Effect of Vacuum Ultraviolet Exposure and Surface Oxide Layer on the Hydrogen Desorption from Hydrogenated Diamond-like Carbon Films

  Masahito Tagawa, Kumiko Yokota, Yuichi Furuyama, Kazuhiro Kanda, Mayumi Tode, Akitaka Yoshigoe, Yuden Teraoka

  第5回JEAE放射光科学シンポジウム, Feb. 2010, English, JAEA, 佐用町, Domestic conference

  Poster presentation


• Departure Process of Hydrogen from Highly-Hydrogenated Diamond-Like Carbon Film by Exposure to Synchrotron Radiation

  Kazuhiro Kanda, Kumiko Yokota, Masahito Tagawa, Mayumi Tode, Yuden Teraoka, Shinji Matsui

  第5回JEAE放射光科学シンポジウム, Feb. 2010, English, JAEA, 佐用町, Domestic conference

  Poster presentation


• 軟X線照射による高水素化DLC膜の表面改質

  Kazuhiro Kanda, Kumiko Yokota, Masahito Tagawa, Shinji Matsui

  第23回放射光学会年会・合同シンポジウム, Jan. 2010, Japanese, 日本放射光学会, 姫路市, Domestic conference

  Oral presentation


• 原子状酸素地上試験の高精度化について

  Kumiko Yokota, Kazuhiro Kishida, Masahito Tagawa

  第26回宇宙利用シンポジウム, Jan. 2010, Japanese, JAXA, 相模原市, Domestic conference

  Poster presentation


• 衛星搭載用原子状酸素センサーのキャリブレーション法について

  Masahito Tagawa, Kazuhiro Kishida, Kumiko Yokota

  第26回宇宙利用シンポジウム, Jan. 2010, Japanese, JAXA, 相模原市, Domestic conference

  Poster presentation


• 宇宙用木質材料への原子状酸素の照射効果

  Takeshi Kajimoto, Toshimitu hata, Masahito Tagawa, Hirotugu Kojima, Hiroshi Yamakawa, Yoshikatsu Ueda

  第2回宇宙環境利用シンポジウム(第133回生存圏シンポジウム), Dec. 2009, Japanese, 京都大学, 宇治市, Domestic conference

  Oral presentation


• 11th Int. Symposium On Materials in a Space Environment 報告

  Masahito Tagawa, Minoru Iwata

  宇宙材料の熱物性とシステムデザイン第6回研究会, Dec. 2009, Japanese, 日本熱物性学会, 東京都, Domestic conference

  Oral presentation


• 炭酸ガスレーザー励起酸素プラズマからの極端紫外線分光

  Masahito Tagawa, Kumiko Yokota, Hiroyuki Shimamura, Yugo Kimoto, Mayuko Koga, Hiroaki Nishimura

  第50回真空に関する連合講演会, Nov. 2009, Japanese, 日本真空協会, 東京都, Domestic conference

  Oral presentation


• 水素化ダイヤモンドライクカーボンの表面処理と水素定量解析

  Masahito Tagawa, Kumiko Yokota

  NEDO水素貯蔵材料先端基盤研究事業 第5回材料物性グループ研究会, Nov. 2009, Japanese, JAEA, 佐用町, Domestic conference

  Oral presentation


• 高水素化DLCフィルムへの紫外線照射による脱水素化反応

  Kumiko Yokota, Masahito Tagawa, Koji Matsumoto, Kazuhiro Kanda, Akira Kitamura

  第50回真空に関する連合講演会, Nov. 2009, Japanese, 日本真空協会, 東京都, Domestic conference

  Oral presentation


• フッ素系ポリマーエロージョンにおける原子状酸素衝突エネルギーの効果

  Kazuhiro Kishida, Masahito Tagawa, Kumiko Yokota

  第46回日本航空宇宙学会中部・関西支部合同秋季大会, Nov. 2009, Japanese, 日本航空宇宙学会, 京都市, Domestic conference

  Oral presentation


• 低軌道におけるテフロン系熱制御材の劣化機構:原子状酸素、紫外線、それとも?

  Kumiko Yokota, Masahito Tagawa

  第30回日本熱物性シンポジウム,, Oct. 2009, Japanese, 日本熱物性学会, 米沢市, Domestic conference

  Oral presentation


• 地上設備を用いた低軌道原子状酸素環境試験:本当に宇宙環境を模擬できているのか?

  Masahito Tagawa, Kumiko Yokota

  第30回日本熱物性シンポジウム,, Oct. 2009, Japanese, 日本熱物性学会, 米沢市, Domestic conference

  Oral presentation


• 衛星搭載用原子状酸素モニター装置の地上キャリブレーションに関する一考察

  Masahito Tagawa, Kumiko Yokota

  第6回宇宙環境シンポジウム, Oct. 2009, Japanese, JAXA, 北九州市, Domestic conference

  Oral presentation


• 超低高度技術試験衛星(SLATS)開発に利用可能な原子状酸素地上試験装置の特性と限界

  Masahito Tagawa, Kumiko Yokota

  第53回宇宙科学技術連合講演会アブストラクト集, Sep. 2009, Japanese, 日本航空宇宙学会, 京都市, Domestic conference

  Oral presentation


• 高水素化DLC膜に対する軟X線照射効果

  Kazuhiro Kanda, Masahito Niibe, Kumiko Yokota, Masahito Tagawa, Shinji Matsui

  第70回応用物理学会学術講演会, Sep. 2009, Japanese, 応用物理学会, 富山市, Domestic conference

  Oral presentation


• 宇宙環境下で原子線表面反応により生成する分子コンタミネーション

  Masahito Tagawa, Kumiko Yokota

  第70回応用物理学会学術講演会, Sep. 2009, Japanese, 応用物理学会, 富山市, Domestic conference

  Oral presentation


• フッ素系高分子のエッチングに及ぼす酸素原子衝突エネルギーの効果

  Kumiko Yokota, Kazuhiro Kishida, Akio Okamoto, Masahito Tagawa

  第70回応用物理学会学術講演会, Sep. 2009, Japanese, 応用物理学会, 富山市, Domestic conference

  Oral presentation


• 生体材料への細胞接着・増殖性におよぼす原子ビーム表面改質効果

  Kumiko Yokota, Chiaki Hiwa, Masahito Tagawa, Yoshikazu Nakai, Taiji Adachi

  電気学会研究会資料、量子・光デバイス研究会, May 2009, Japanese, 電気学会, 神戸市, Domestic conference

  Oral presentation


• 低軌道宇宙環境模擬用レーザーデトネーション型原子状酸素発生装置から発生する極端紫外線の評価とその応用に関する研究

  Masahito Tagawa, Kumiko Yokota

  レーザー研シンポジウム2009, Apr. 2009, Japanese, 大阪大学, 吹田市, Domestic conference

  Oral presentation


• 水素化ダイヤモンドライクカーボンの表面処理と水素定量解析

  Masahito Tagawa, Kumiko Yokota

  NEDO水素貯蔵材料先端基盤研究事業 第4回材料物性グループ研究会, Mar. 2009, Japanese, JAEA, 佐用町, Domestic conference

  Oral presentation


• 宇宙材料の耐環境性試験:現状と問題点

  Masahito Tagawa

  宇宙材料の熱物性とシステムデザイン第4回研究会, Mar. 2009, Japanese, 日本熱物性学会, 東京都, Domestic conference

  Oral presentation


• 大気吸入型イオンエンジン(ABIE)に関する実験的研究

  Masahito Tagawa, Kazutaka Nishiyama, Kumiko Yokota, Yasuo Yoshizawa, Daisaku Yamamoto, Hitoshi Kuninaka

  平成20年度宇宙輸送シンポジウム, Jan. 2009, Japanese, JAXA, 相模原市, Domestic conference

  Oral presentation


• 水素含有DLC薄膜の光電子分光

  Yuichi Haruyama, Masahito Tagawa, Kumiko Yokota, Shinji Matsui

  第22回日本放射光学会年会放射光科学合同シンポジウム, Jan. 2009, Japanese, 日本放射光学会, 東京都, Domestic conference

  Oral presentation


• 2008年度軌道上材料曝露実験高度化ワーキンググループ活動報告

  Masahito Tagawa, Kumiko Yokota, Mengu Cho, Minoru Iwata, Rikio Yokota, Mineo Suzuki, Koji Matsumoto, Yugo Kimoto, Hiroyuki Shimamura

  第25回宇宙利用シンポジウム, Jan. 2009, Japanese, JAXA, 相模原市, Domestic conference

  Oral presentation


• 宇宙環境と人工衛星-極限環境への挑戦-

  Masahito Tagawa, Kumiko Yokota

  日本航空宇宙学会関西支部2008年度ライト祭, Dec. 2008, Japanese, 日本航空宇宙学会, 大阪市, Domestic conference

  Oral presentation


• Problems and recent trends on material degradation studies in a real and simulated space environment

  Masahito Tagawa, Kumiko Yokota

  第5回宇宙環境シンポジウム, Dec. 2008, Japanese, JAXA, つくば市, Domestic conference

  Oral presentation


• 模擬複合宇宙環境地上試験におけるフッ素系ポリマーのシナジー効果

  Kazuhiro Kishida, Masahito Tagawa, Kumiko Yokota

  第45回日本航空宇宙学会中部・関西支部合同秋季大会, Nov. 2008, Japanese, 日本航空宇宙学会, 名古屋市, Domestic conference

  Oral presentation


• 低軌道における原子状酸素誘起材料劣化とその分子コンタミネーション源としての可能性(2)"

  Kumiko Yokota, Masahito Tagawa

  第52回宇宙科学技術連合講演会アブストラクト集, Nov. 2008, Japanese, 日本航空宇宙学会, 淡路市, Domestic conference

  Oral presentation


• 原子状酸素誘起ポリイミド質量減少における衝突エネルギーの効果

  Masahito Tagawa, Kazuhiro Kishida, Kumiko Yokota

  第52回宇宙科学技術連合講演会アブストラクト集, Nov. 2008, Japanese, 日本航空宇宙学会, 淡路市, Domestic conference

  Oral presentation


• シロキサン変性ポリイミドフィルムの耐原子状酸素性評価

  Eiji Miyazaki, Masahito Tagawa, Rikio Yokota, Junichiro Ishizawa, Yugo Kimoto

  第52回宇宙科学技術連合講演会アブストラクト集, Nov. 2008, Japanese, 日本航空宇宙学会, 淡路市, Domestic conference

  Oral presentation


• 水素化DLC膜の軟X線照射による改質効果

  kazuhiro kanda, Masahito Niibe, Masahito Tagawa, Kumiko Yokota, Shinji Matsui

  第22回ダイヤモンドシンポジウム, Oct. 2008, Japanese, ニューダイヤモンドフォーラム, 東京都, Domestic conference

  Oral presentation


• 宇宙環境における熱制御材料の劣化現象

  Masahito Tagawa, Kumiko Yokota

  第29回日本熱物性シンポジウム,, Oct. 2008, Japanese, 日本熱物性学会, 東京都, Domestic conference

  Oral presentation


• 水素含有ダイヤモンドライクカーボン薄膜の電子状態

  Yuichi Haruyama, Masahito Tagawa, Kumiko Yokota, Shinji Matsui

  日本物理学会2008秋季大会, Sep. 2008, Japanese, 日本物理学会, 岩手市, Domestic conference

  Oral presentation


• 原子状酸素を照射した水素化ダイヤモンドライクカーボン薄膜の水素分布

  Masahito Tagawa, Kumiko Yokota, Akira Kitamura, Koji Matsumoto, Akitaka Yoshigoe, Yuden Teraoka

  第69回応用物理学会学術講演会, Sep. 2008, Japanese, 応用物理学会, 春日井市, Domestic conference

  Oral presentation


• 原子ビームにより表面改質した生体材料の細胞接着性

  YOKOTA Kumiko, HIWA Chiaki, TAGAWA Masato, 安達 泰治, NAKAI Yoshikazu

  M&M2008材料力学カンファレンス, Sep. 2008, Japanese, 日本機械学会, 草津市, Domestic conference

  Oral presentation


• フッ素系高分子材料の劣化に及ぼす原子状酸素と極端紫外線の複合効果

  Kumiko Yokota, Kazuhiro Kishida, Masahito Tagawa, Akio Okamoto

  第69回応用物理学会学術講演会, Sep. 2008, Japanese, 応用物理学会, 春日井市, Domestic conference

  Oral presentation


• 神戸大学機械工学科におけるものづくり導入教育

  ASANO Hitoshi, TAGAWA Masato, HOSOKAWA Shigeo, HIWA Chiaki, ADACHI Kazuhiko

  平成20年度工学・工業教育研究講演会, Aug. 2008, Japanese, 日本工学教育協会, 神戸, Domestic conference

  Oral presentation


• 摩擦誘起極表面改質ダイヤモンドライクカーボン薄膜の放射光/超音速分子線による非破壊評価

  Tagawa Masahito, Yokota Kumiko, Yoshigoe Akitaka, Teraoka Yuden, Matsumoto Koji

  第3回JAEA放射光科学研究シンポジウム, Mar. 2008, Japanese, 日本原子力研究開発機構, 兵庫県、佐用郡, Domestic conference

  Poster presentation


• 水素化ダイヤモンドライクカーボンの表面処理と水素定量解析

  Masahito Tagawa, Kumiko Yokota

  第2回NEDO水素貯蔵材料先端基盤研究事業材料物性グループ研究会, Mar. 2008, Japanese, JAEA, 佐用町, Domestic conference

  Oral presentation


• 宇宙航空技術におけるEUV光アブレーション

  Tagawa Masahito, Yokota Kumiko

  第55回応用物理学関係連合講演会, Mar. 2008, Japanese, 応用物理学会, 千葉県、船橋市, Domestic conference

  [Invited]

  Invited oral presentation


• 低軌道宇宙環境下での材料曝露試験高度化のための原子状酸素収束化技術の開発

  Tagawa Masahito, Yokota Kumiko

  第24回宇宙利用シンポジウム, Jan. 2008, Japanese, 日本学術会議, 東京都, Domestic conference

  [Invited]

  Invited oral presentation


• 軌道上材料曝露実験高度化ワーキンググループ活動報告

  Tagawa Masahito, Yokota Kumiko, Suzuki Mineo, Miyazaki Eiji, Shimamura Hiroyuki, Matsumoto Koji, Yokota Rikio, Cho Mengu, Iwata Minoru

  第24回宇宙利用シンポジウム, Jan. 2008, Japanese, 日本学術会議, 東京都, Domestic conference

  [Invited]

  Invited oral presentation


• Erosion properties of polyimide as a monitoring material of atomic oxygen environment in space (3): Synergistic effect of atomic oxygen and ultraviolet

  Tagawa Masahito, Yokota Kumiko

  第4回宇宙環境シンポジウム, Jan. 2008, English, 宇宙航空研究開発機構, 東京都, International conference

  [Invited]

  Invited oral presentation


• 超熱酸素原子線による水素化ダイヤモンドライクカーボン薄膜の選択的エッチング

  Tagawa Masahito, Yokota Kumiko, Kitamura Akira, Matsumoto Koji, Yamada Noriko, Kanda Kazuhiro, Niibe Masato, Yoshigoe Akitaka, Teraoka Yuden, Belin Michel, Fontaine Julien

  第48回真空に関する連合講演会, Nov. 2007, Japanese, 日本真空協会, 東京都, Domestic conference

  Oral presentation


• 極端紫外線を除去可能な宇宙材料試験用レーザーデトネーション型原子状酸素発生装置

  Yokota Kumiko, Okamoto Akio, Kishida Kazuhiro, Yasuda Hidehiro, Tagawa Masahito

  第48回真空に関する連合講演会, Nov. 2007, Japanese, 日本真空協会, 東京都, Domestic conference

  Oral presentation


• 低軌道宇宙環境における水素化ダイヤモンドライクカーボン薄膜と原子状酸素の反応

  Tagawa Masahito, Yokota Kumiko, Matsumoto Koji, Kitamura Akira, Yamada Noriko, Kanda Kazuhiro, Niibe Masato, Yoshigoe Akitaka, Teraoka Yuden, Belin Michel, Fontaine Julien

  第51回宇宙科学技術連合講演会, Oct. 2007, Japanese, 日本航空宇宙学会, 北海道、札幌市, Domestic conference

  Oral presentation


• 低軌道における原子状酸素誘起材料劣化とその分子コンタミネーション源としての可能性

  Yokota Kumiko, Tagawa Masahito

  第51回宇宙科学技術連合講演会, Oct. 2007, Japanese, 日本航空宇宙学会, 北海道、札幌市, Domestic conference

  Oral presentation


• 複合宇宙環境下における材料劣化現象とそのコンタミネーションソースとしての可能性

  Tagawa Masahito, Yokota Kumiko

  第1回コンタミネーション管理技術ワークショップ, Sep. 2007, Japanese, 物質材料研究機構, つくば市, Domestic conference

  [Invited]

  Invited oral presentation


• 超熱フッ素原子ビームを用いたポリイミド表面のフッ素化と直接無電解めっき技術の開発(2)

  Tagawa Masahito, Maeda Kenichi, Yokota Kumiko, Akamatsu Kensuke, Nawafune Hidemi

  第68回応用物理学会学術講演会, Sep. 2007, Japanese, 応用物理学会, 北海道、札幌市, Domestic conference

  Oral presentation


• 超熱フッ素原子ビームを用いたダイヤモンドライクカーボンの表面改質

  Yamada Noriko, Kanda Kazuhiro, Yokota Kumiko, Tagawa Masahito, Haruyama Yuichi, Matsui Shinji

  第68回応用物理学会学術講演会, Sep. 2007, Japanese, 応用物理学会, 北海道、札幌市, Domestic conference

  Oral presentation


• レーザーデトネーション型原子線源からの極端紫外線除去用高速回転チョッパーシステム

  Yokota Kumiko, Abe Shingo, Yasuda Hidehiro, Tagawa Masahito

  第68回応用物理学会学術講演会, Sep. 2007, Japanese, 応用物理学会, 北海道、札幌市, Domestic conference

  Oral presentation


• 二硫化モリブデン焼成膜の宇宙環境曝露による特性変化

  Matsumoto Koji, Akiyama Masao, Tagawa Masahito

  国際宇宙ステーション軌道環境技術-特殊真空対応技術の展開, Jun. 2007, Japanese, 日本真空協会, 東京都, Domestic conference

  [Invited]

  Invited oral presentation


• 低軌道原子状酸素環境の地上シミュレーション

  Tagawa Masahito, Yokota Kumiko

  日本地球惑星科学連合2007年大会, May 2007, Japanese, 日本地球惑星科学連合, 東京都, Domestic conference

  Oral presentation


• Photoemission Analysis with Synchrotron Radiation for Nitridation of SiO2 Thin Film on Si(001) by Irradiation of N+ Ion Beams

  TERAOKA Yuden, HACHIUE Shynsuke, YOKOTA Kumiko, TAGAWA Masahito

  American Vacuum Society 53rd International Symposium and Exhibition, Nov. 2006, English, San Francisco, International conference

  Oral presentation


• Surface oxidation and tribological properties of a hydrogenated DLC exposed to a simulated low earth orbit space environment

  TAGAWA Masahito, YOKOTA Kumiko, OOHARA Hisanori, NAKAHIGASHI Takahiro, TERAOKA Yuden, MARTIN Jean-Miche, BELIN Michel

  The 3rd International Conference on Tribology, Oct. 2006, English, Kanazawa, International conference

  Poster presentation


• Hyperthermal molecular beam deposition of DLC using laser-induced detonation phenomena

  TAGAWA Masahito, ASADA Hidetoshi, MATSUURA Yoshimitsu, YOKOTA Kuimiko, TERAOKA Yuden, KITAMURA Akira, FONTAINE Julien, BELIN Michel

  The 3rd International Conference on Tribology, Oct. 2006, English, Kanazawa, International conference

  Oral presentation


• Synchrotron radiation photoemission spectroscopic study on the room temperature oxidation of Si(001):H formed by hyperthermal atomic/molecular beams

  TAGAWA Masahito, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden

  the 232nd American Chemical Society National Meeting and exhibition, Sep. 2006, English, San Francisco, International conference

  [Invited]

  Invited oral presentation


• SM/SEED flight experimental results on molybdenum disulfide-based solid lubricants

  TAGAWA Masahito, ASADA Hidetoshi, YOKOTA Kumiko, MATSUMOTO Koji, AKIYAMA Masao

  ISTS-25, Jun. 2006, English, Kanazawa, International conference

  Oral presentation


• Comparative study of polyimide and FEP on the simultaneous exposure effects on atomic oxygen and ultraviolet

  YOKOTA kumiko, OKAMOTO Akio, TAGAWA Masahito

  ISTS-25, Jun. 2006, English, Kanazawa, International conference

  Oral presentation


• Atomic Oxygen concentration for material exposure acceleration tests in low earth orbit

  YOKOTA kumiko, IKEDA Kohei, OKAMOTO Akio, TAGAWA Masahito

  10th International Symposium on Materials in Space Environment, 8th International Space Conference, Jun. 2006, English, Collioure, International conference

  Oral presentation


• Atomic Oxygen concentration for material exposure acceleration tests in low earth orbi

  TAGAWA Masahito, DOI Hiroaki, YOKOTA Kumiko

  10th International Symposium on Materials in Space Environment, Jun. 2006, English, Collioure, International conference

  Oral presentation


• A novel room temperature oxidation technique using hyperthermal broad atomic/molecular beams

  TAGAWA Masahito, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden

  2nd International Symposium on Oxidation Reaction, May 2006, English, Osaka, International conference

  Oral presentation


• 超熱酸素・窒素分子ビームを用いたSi表面の酸化・窒化膜形成とその光電子分光分析

  TAGAWA Masahito, YOKOTA Kumiko, TERAOKA Yuden, YOSHIGOE Akitaka

  第1回JAEA放射光科学シンポジウム, Mar. 2006, Japanese, SPring-8, Domestic conference

  Poster presentation


• 低地球軌道上の原子状酸素によるシリコン酸化膜形成とその特徴 (3)

  YOKOTA kumiko, TAGAWA Masahito, YOSHIGOE Akitaka, TERAOKA Yuden

  第22回宇宙利用シンポジウム講演予稿集, Jan. 2006, Japanese, 東京, Domestic conference

  Oral presentation


• Surface and tribological properties of the MoS2-based lubricants retrieved from real LEO space environment: the first and second year results obtained by SM/SEED

  AKIYAMA Masao, MATSUMOTO Koji, IMAGAWA Kichiro, OCHI Kunitaka, ASADA Hidetoshi, YOKOTA Kumiko, TAGAWA Masahito

  11th European Space Mechanisms and Tribology Symposium, Sep. 2005, English, Lucerne, International conference

  Poster presentation


• Changes in Tribological Properties of MoS2 film exposed to LEO on SM/SEED

  MATSUMOTO Koji, IMAGAWA Kichiro, AKIYAMA Masao, TAGAWA Masahito

  World Tribology Congress III,, Sep. 2005, English, Washington D.C., International conference

  Poster presentation


• Atomic oxygen-induced erosion of spacecraft materials -Potential hazards for spacecraft systems

  TAGAWA Masahito

  9th Spacecraft Charging Technology Conference (Plenary), Apr. 2005, English, つくば, International conference

  [Invited]

  Invited oral presentation


• 低地球軌道上の原子状酸素利用に向けての収束化技術の開発 (3)

  Masahito Tagawa, Kumiko Yokota

  第21回宇宙利用シンポジウム, 2005, Japanese, 東京, Domestic conference

  Oral presentation


• 超熱原子ビームによる高分子表面改質

  Masahito Tagawa

  スリービーム技術による表面改質と解析（招待講演）, 2005, Japanese, 和光, Domestic conference

  [Invited]

  Invited oral presentation


• レーザーデトネーション誘起高速原子ビーム励起表面反応

  Masahito Tagawa

  量子ビーム理工学研究最前線-その現状と今後の展望-, 2005, Japanese, Kobe, Domestic conference

  Poster presentation


• Surface degradation of polymeric materials under hyperthermal atomic oxygen beam bombardment; temperature dependence

  YOKOTA Kumiko, TAGAWA Masahito, SEIKYU Shinsuke, OHMAE Nobuo

  International Symposium on Applications of Quantum Beam 2005, 2005, English, Kobe, International conference

  Poster presentation


• Photoemission spectroscopy with synchrotron radiation for nitrogen-impinged Si(001) surfaces with an ultra-thin-SiO2 overlayer

  HACHIUE Syunsuke, TERAOKA Yuden, TAGAWA Masahito

  11th European Conference on Applications of Surface and Interfac, 2005, English, Vienna, International conference

  Poster presentation


• Passive oxidation of Si(001) by hyperthermal atomic oxygen beam -A synchrotron radiation photoemission spectroscopic study-

  TAGAWA Masahito, SOGO Chie, MIYAGAI Suguru, YOKOTA Kumiko, YOSHIGOE Akitaka, TERAOKA Yuden

  International Symposium on Applications of Quantum Beam 2005, 2005, English, Kobe, International conference

  Poster presentation


• Atomic oxygen-induced polymer degradation phenomena in simulated LEO space environments: How do polymers react in a complicated space environment?

  TAGAWA Masahito, YOKOTA Kumiko

  56th International Astronautical Congress, 2005, English, Fukuoka, International conference

  Oral presentation


• Atomic oxygen-induced erosion of polymeric materials under surface charging conditio

  YOKOTA Kumiko, OHMAE Nobuo, SEIKYU Shinsuke, TAGAWA Masahito

  9th Spacecraft Charging Technology Conference, 2005, English, つくば, International conference

  Oral presentation


• プラズマCVD法により作製したカーボンナノチューブの配向制御

  KUME Ippei, SAKAI Hirokazu, KINOSHITA Hiroshi, TAGAWA Masahito, SEIKYU Shinsuke, OHMAE Nobuo

  第51回応用物理学関係連合講演会, Mar. 2004, Japanese, 応用物理学会, 東京工科大学, Domestic conference

  Oral presentation


• 表面帯電時における原子状酸素誘起高分子エロージョン

  横田 久美子, 田川 雅人

  第1回宇宙環境シンポジウム, 2004, Japanese, 日本航空宇宙学会関西支部, 宇宙航空研究開発機構, Domestic conference

  Oral presentation


• 熱電子原子ビームによる炭素系薄膜作成の試み

  浅田 秀俊, 横田 久美子, 大前 伸夫, 田川 雅人

  第45回真空に関する連合講演会, 2004, Japanese, 日本真空協会, 大阪大学, Domestic conference

  Oral presentation


• 二硫化モリブデン皮膜に及ぼす原子状酸素と紫外線の複合効果－第2報－

  MATSUMOTO Koji, SUZUKI Mineo, OBARA Shingo, TAGAWA Masahito

  トライボロジー会議2004秋, 2004, Japanese, 日本トライボロジー学会, 鳥取, Domestic conference

  Oral presentation


• 低地球軌道上の原子状酸素環境利用に向けての収束化技術の開発(2)

  田川 雅人, 横田 久美子, 大前 伸夫

  第20回宇宙利用シンポジウム, 2004, Japanese, 宇宙航空研究開発機構, 宇宙航空研究開発機構・宇宙科学研究本部, Domestic conference

  Oral presentation


• 低地球軌道上の原子状酸素によるシリコン酸化膜形成とその特徴

  横田 久美子, 大前 伸夫, 田川 雅人

  第20回宇宙利用シンポジウム, 2004, Japanese, 宇宙航空研究開発機構, 宇宙航空研究開発機構・宇宙科学研究本部, Domestic conference

  Oral presentation


• 低地球軌道上における高効率原子状酸素収束化技術の開発(2)

  DOI Hiroaki, YOKOTA Kumiko, OHMAE Nobuo, TAGAWA Masahito

  第41回日本航空宇宙学会中部関西支部合同秋期大会, 2004, Japanese, 日本航空宇宙学会関西支部, 名城大学, Domestic conference

  Oral presentation


• 低軌道宇宙環境におけるポリイミドの表面劣化(3)－原子状酸素と紫外線の複合照射における定量化－

  横田 久美子, 清久 慎右, 田川 雅人, 大前 伸夫

  第48回宇宙科学技術連合講演会, 2004, Japanese, 日本航空宇宙学会, 福井県福井市, Domestic conference

  Oral presentation


• 超熱原子状酸素ビームによる高分子材料のガス化反応－高温での温度依存性について－

  YOKOTA kumiko, SEIKYU Shinsuke, OHMAE Nobuo, TAGAWA Masahito

  第65回応用物理学会学術講演会, 2004, Japanese, 応用物理学会, 東北学院大学, Domestic conference

  Oral presentation


• 超熱原子状酸素ビームによる高分子材料のガス化反応－温度依存性について－

  横田 久美子, 田川 雅人, 清久 慎右, 大前 伸夫

  第51回応用物理学関係連合講演会, 2004, Japanese, 応用物理学会, 東京工科大学, Domestic conference

  Oral presentation


• 超熱原子状酸素ビームによるSi02極薄膜の形成

  SOGO Chie, YOKOTA Kumiko, OHMAE Nobuo, TAGAWA Masahito, YOSHIGOE Akitaka, TERAOKA Yuden

  第45回真空に関する連合講演会, 2004, Japanese, 日本真空協会, 大阪大学, Domestic conference

  Oral presentation


• 超熱原子状酸素ビームにより形成したSi(001)極薄酸化膜のXPS解析

  SOGO Chie, 裙本 晋之助, 横田 久美子, 田川 雅人, 大前 伸夫, 寺岡 有殿

  第51回応用物理学関係連合講演会, 2004, Japanese, 応用物理学会, 東京工科大学, Domestic conference

  Oral presentation


• 超熱原子状フッ素ビームの形成と評価

  前田 健一, 横田 久美子, 大前 伸夫, 田川 雅人

  第45回真空に関する連合講演会, 2004, Japanese, 日本真空協会, 大阪大学, Domestic conference

  Oral presentation


• 走査電子顕微鏡組込みマイクロトライボメーターによる垂直配向カーボンナノチューブ薄膜のマイクロトライボロジーの解明

  木之下 博, 久米 一平, 田川 雅人, 大前 伸夫

  第65回応用物理学会学術講演会, 2004, Japanese, 応用物理学会, 東北学院大学, Domestic conference

  Oral presentation


• 垂直配向カーボンナノチューブ薄膜のマイクロトライボロジー

  木之下 博, 久米 一平, 酒井 洋和, 田川 雅人, 大前 伸夫

  第51回応用物理学関係連合講演会, 2004, Japanese, 応用物理学会, 東京工科大学, Domestic conference

  Oral presentation


• 原子状酸素誘起高分子材料劣化における表面帯電の影響

  清久 慎右, 横田 久美子, 大前 伸夫, 田川 雅人

  第41回日本航空宇宙学会中部関西支部合同秋期大会, 2004, Japanese, 日本航空宇宙学会関西支部, 名城大学, Domestic conference

  Oral presentation


• 原子状酸素収束器の開発(3)

  田川 雅人, 土井 洋明, 横田 久美子, 大前 伸夫

  第48回宇宙科学技術連合講演会, 2004, Japanese, 日本航空宇宙学会, 福井県福井市, Domestic conference

  Oral presentation


• 原子ビームを用いた細胞のマイクロパターンニング

  河東 万智子, 安達 泰治, 佐藤 克也, 田川 雅人

  関西支部第79期定時総会講演会, 2004, Japanese, 日本機械学会関西支部, 大阪府立大学, Domestic conference

  Oral presentation


• 円周走査型走査原子間力顕微鏡による局面形状の精密測定

  木之下 博, 田川 雅人, 大前 伸夫

  トライボロジー会議2004秋, 2004, Japanese, 日本トライボロジー学会, 鳥取, Domestic conference

  Oral presentation


• プラズマCVD法により作製したカーボンナノチューブの配向性制

  久米 一平, 酒井 洋和, 木之下 博, 田川 雅人, 大前 伸夫

  第52回応用物理学関係連合講演会, 2004, Japanese, 応用物理学会, 未記入, Domestic conference

  Oral presentation


• コンピュータシミュレーションによるホーン型原子状酸素収束器の最適化

  田川 雅人, 土井 洋明, 横田 久美子, 大前 伸夫

  第51回応用物理学関係連合講演会, 2004, Japanese, 応用物理学会, 東京工科大学, Domestic conference

  Oral presentation


• カーボンナノチューブ薄膜のマイクロトライボロジー －走査電子顕微鏡組込みマイクロトライボメーターによる観察－

  木之下 博, 久米 一平, 田川 雅人, 大前 伸夫

  トライボロジー会議2004春, 2004, Japanese, 日本トライボロジー学会, 機械振興会館, Domestic conference

  Oral presentation


• カーボンナノチューブ薄膜のマイクロトライボロジー特性におよぼす摩擦相手材の影響

  木之下 博, 久米 一平, 大畠 民生, 田川 雅人, 大前 伸夫

  トライボロジー会議2004秋, 2004, Japanese, 日本トライボロジー学会, 鳥取, Domestic conference

  Oral presentation


• Si基板上に成長させたC60薄膜のナノトライボロジー特性

  鈴木 宏樹, 木之下 博, 田川 雅人, 大前 伸夫

  トライボロジー会議2004秋, 2004, Japanese, 日本トライボロジー学会, 鳥取, Domestic conference

  Oral presentation


• Si(111)表面からのアルカリ金属イオン放出

  OHNISHI Yuki, OHMAE Nobuo, TAGAWA Masahito, SHIOTA Tadashi

  第65回応用物理学会学術講演会, 2004, Japanese, 応用物理学会, 東北学院大学, Domestic conference

  Oral presentation


• Si(001)の超熱原子状酸素ビーム酸化における酸化曲線

  田川 雅人, 十河 千恵, 横田 久美子, 大前 伸夫, 寺岡 有殿

  第65回応用物理学会学術講演会, 2004, Japanese, 応用物理学会, 東北学院大学, Domestic conference

  Oral presentation


• MoS2焼成膜の宇宙環境曝露での劣化特性について－SM－SEED軌道上１年曝露－

  田川 雅人, 松本 康司, 秋山 正雄

  第48回宇宙科学技術連合講演会, 2004, Japanese, 日本航空宇宙学会, 福井県福井市, Domestic conference

  Oral presentation


• mN荷重域でのカーボンナノチューブ薄膜のトライボロジー特性

  KUME Ippei, OKADA Shinsaku, KINOSHITA Hiroshi, TAGAWA Masahito, OHMAE Nobuo

  トライボロジー会議2004秋, 2004, Japanese, 日本トライボロジー学会, 鳥取, Domestic conference

  Oral presentation


• 低地球軌道上における高効率原子状酸素収束化技術の開発

  土井 洋明, 横田 久美子, 田川 雅人, 大前 伸夫

  第40回日本航空宇宙学会関西・中部支部合同秋季大会, 2003, Japanese, 日本航空宇宙学会関西・中部支部, 神戸大学 神大会館, Domestic conference

  Oral presentation


• 低軌道宇宙環境の原子状酸素を用いたSi酸化膜の形成

  十河 千恵, 裙本 晋之助, 横田 久美子, 田川 雅人, 大前 伸夫

  第40回日本航空宇宙学会関西・中部支部合同秋季大会, 2003, Japanese, 日本航空宇宙学会関西・中部支部, 神戸大学 神大会館, Domestic conference

  Oral presentation


• 低軌道宇宙環境におけるポリイミドの表面劣化（3）－原子状酸素を紫外線の複合照射における定量化－

  横田 久美子, 清久 慎介, 田川 雅人, 大前 伸夫

  第47回宇宙科学技術連合講演会, 2003, Japanese, 日本航空宇宙学会, 新潟コンベンションセンター, Domestic conference

  Oral presentation


• 超熱原子状酸素によるSiO2酸化膜の室温形成

  裙本 晋之助, 十河 千恵, 木之下 博, 横田 久美子, 田川 雅人, 大前 伸夫

  第64回応用物理学会学術講演会, 2003, Japanese, 応用物理学会, 福岡大学, Domestic conference

  Oral presentation


• 炭素系材料マイクロトライボロジー特性におよぼす相対湿度の影響

  木之下 博, 久米 一平, 酒井 洋和, 田川 雅人, 大前 伸夫

  トライボロジー会議, 2003, Japanese, 日本トライボロジー学会, 新潟, Domestic conference

  Oral presentation


• 原子状酸素照射時の温度および紫外線の複合効果

  清久 慎右, 横田 久美子, 田川 雅人, 大前 伸夫

  第40回日本航空宇宙学会関西・中部支部合同秋季大会, 2003, Japanese, 日本航空宇宙学会関西・中部支部, 神戸大学 神大会館, Domestic conference

  Oral presentation


• 原子状酸素収束器の開発(2)

  田川 雅人, 土井 洋明, 横田 久美子, 大前 伸夫

  第47回宇宙科学技術連合講演会, 2003, Japanese, 日本航空宇宙学会, 新潟コンベンションセンター, Domestic conference

  Oral presentation


• 原子状酸素ビーム照射によるポリイミドの質量減少：入射角依存性について

  横田 久美子, 田川 雅人, 清久 慎右, 大前 伸夫

  第64回応用物理学会学術講演会, 2003, Japanese, 応用物理学会, 福岡大学, Domestic conference

  Oral presentation


• 原子ビームを用いた材料表面改質と細胞接着制御

  安達 泰治, 梶田 文昭, 佐藤 克也, 松本 康志, 田川 雅人

  日本材料学会第52期学術講演会, 2003, Japanese, 日本材料学会, 工学院大学, Domestic conference

  Oral presentation


• 急冷却時におけるSi（111）からの非定常イオン放出現象

  寺本 泰章, 大西 優輝, 田川 雅人, 大前 伸夫, 塩田 忠

  第44回真空に関する連合講演会, 2003, Japanese, 日本真空協会, 機械振興会館, Domestic conference

  Oral presentation


• 宇宙用高分子材料の原子状酸素劣化における帯電の影響－神戸大学の取り組み－

  横田 久美子, 前田 健一, 清久 慎右, 大前 伸夫, 田川 雅人

  第6回宇宙飛翔体環境研究会, 2003, Japanese, 地球電磁気・地球惑星圏学会分科会, 筑波宇宙センター, Domestic conference

  Oral presentation


• コンピュータシミュレーションによる原子状酸素収束用ミラーの最適化

  田川 雅人, 土井 洋明, 横田 久美子, 大前 伸夫

  第64回応用物理学会学術講演会, 2003, Japanese, 応用物理学会, 福岡大学, Domestic conference

  Oral presentation


• カーボンナノチューブの生成とマイクロトライボロジー特性

  久米 一平, 坂井 洋和, 木之下 博, 田川 雅人, 大前 伸夫

  トライボロジー会議, 2003, Japanese, 日本トライボロジー学会, 新潟, Domestic conference

  Oral presentation


• 原子状酸素照射による細胞接着パターンの作成

  梶田 文昭, 松本 康志, 佐藤 克也, 田川 雅人, 安達 泰治

  日本機械学会第15回バイオエンジニアリング部門講演会（BE2003）, Jan. 2003, Japanese, 日本機械学会 バイオエンジニアリング部門, 大阪大学コンベンションセンター, Domestic conference

  Oral presentation

• 日本表面科学会


• 日本真空協会


• 日本機械学会


• トライボロジー学会


• アメリカ化学会


• アメリカ航空宇宙学会


• 電気学会


• 日本航空宇宙学会


• 応用物理学会

• その場測定による高分子材料の宇宙軌道上紫外線劣化に関する基礎的研究

  岩田 稔, 田川 雅人, 太刀川 純孝

  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 九州工業大学, 01 Apr. 2022 - 31 Mar. 2027


• A study on neutral-plasma interaction using a comprehensive observation in the sporadic E layer

  阿部 琢美, 熊本 篤志, 田川 雅人, 齊藤 昭則

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Aerospace EXploration Agency, 01 Apr. 2023 - 31 Mar. 2026

  本研究の目的は中性－電離大気の結合が強い高度100km-120kmの領域で、観測ロケット搭載観測機器による中性・電離大気の局所詳細観測を行い、突発的な高電子密度層（スポラディックE層）の形成過程における中性風と粒子間衝突の役割を定量的に理解することにある。従来、電離圏下部の高電子密度層の観測は行われてきたが、我々は観測ロケットに搭載する７つの測定器により世界で初めて中性大気、イオン、電子、電場、磁場の全てのパラメータを直接同時観測する予定であり、本研究の独自性はこの点にある。 2023年度は上に述べた搭載機器中、次の３つの測定器の製作を行った。主な成果は次の通りである 1)中性大気観測装置： イオンゲージを真空測定子とし、大気流の入射方向に強く依存して圧力値が変化、入射方向に対する依存性が低く圧力があまり変化しない２種類の真空計により得られた値を比較し背景圧力と大気流の方向を推定する。今年度は電気回路部、センサ部、センサをロケット機体から離して測定するためのブームを製作し、地上で機器の性能評価試験を行った。 2)インピーダンスプローブ： プラズマのUHR周波数からプラズマ密度を推定するが印加信号をインパルスまたは白色雑音に変更することで時間分解能を向上させる。今年度は測定器の製作を完了し、電離圏プラズマを模擬した環境下で動作することの確認を行った。 3)ラングミュアプローブ： 電流電圧特性取得のための掃引電圧周期を100ミリ秒とし更に数値解析手法に工夫を凝らすことで更に優れた時間分解能でデータ取得を行う。今年度は測定器の製作を完了し、電離圏プラズマを模擬した環境下で動作することの確認を行った。


• 高分子材料の原子状酸素による表面改質：高次構造を活用した微細構造制御法の開拓

  後藤 亜希, 田川 雅人, 満汐 孝治, 山下 真一

  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 国立研究開発法人宇宙航空研究開発機構, 01 Apr. 2023 - 31 Mar. 2026


• Shielding effect analysis on atomic oxygen exposure test using SLATS data and new protocol for future atomic oxygen exposure in VLEO environment

  横田 久美子, 田川 雅人, 岩田 稔

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2022 - Mar. 2026


• Low-drag satellite for VLEO operation realized by design and material optimization

  田川 雅人, 横田 久美子

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2022 - Mar. 2026


• Molecular flow compression intake using microstructured surface applicable to air breathing ion engine

  田川 雅人, 横田 久美子

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory), Grant-in-Aid for Challenging Research (Exploratory), Kobe University, Jun. 2022 - Mar. 2025


• 宇宙ゴミ衝突時のポリイミドCFRPからのイジェクタ発生に与える宇宙環境の複合効果

  西田 政弘, 田川 雅人

  日本学術振興会, 科学研究費助成事業, 基盤研究(C), 名古屋工業大学, 01 Apr. 2019 - 31 Mar. 2023

  電子線，紫外線に強く，耐熱性があるポリイミドを用いたポリイミド樹脂/炭素繊維強化複合材の表面に，耐原子状酸素コーティング（シルセスキオキサン誘導体）を施した材料を宇宙環境に強い材料として提案し，宇宙ゴミを模擬した飛翔体を超高速衝突させ，破壊挙動およびイジェクタ（噴出物）の発生を詳しく調べる．宇宙環境のうち，電子線および原子状酸素を試験片に照射し，それら宇宙環境の影響，特にその複合効果およびメカニズムを明らかにする． 研究期間の1年目（2019年度）は，耐原子状酸素コーティングを施したポリイミド樹脂/炭素繊維強化複合材を作製し，宇宙ゴミを模擬した飛翔体の超高速衝突実験を行い，破壊挙動，主に，貫通孔周りの様子，イジェクタ（噴出物）の発生状況を明らかにした．コーティング厚さ5 μｍ，20 μｍの試験片を作製し，コーティングの影響を調べた．耐原子状酸素コーティングを施したポリイミド樹脂/炭素繊維強化複合材に電子線および原子状酸素を照射し，その試験片を用いた超高速衝突実験を行うことで，貫通孔周りの様子，イジェクタ（噴出物）のサイズ分布を調べた． 2年目の2020年度は，コロナ禍で行動制限の中，コーティング厚さが異なる多種の試験片を作製し，コーティング厚さの影響を詳細に調べた．エポキシ樹脂/炭素繊維強化複合材でもコーティングは有効で，ポリイミド樹脂の場合より薄いコーティングでも効果が明確であることがわかった．また，宇宙環境の影響では，電子線を照射したのちに，原子状酸素を照射した材料に対して調べたところ，その影響は小さいことがわかった． ３年目の2021年度もコロナ禍の中，昨年度の結果から適切なコーティング厚さの試験片を用いて電子線照射のみの影響を調べたところ，照射していない試験片に比べて，イジェクタがわずかに短く，個数も少ない場合があることがわかった．宇宙環境により状況が悪化する結果は得られなかった．


• Under-estimation of space environmental effects on materials in ground-based studies and new testing standards

  田川 雅人, 横田 久美子

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory), Grant-in-Aid for Challenging Research (Exploratory), Kobe University, Jun. 2019 - Mar. 2023

  宇宙用材料・システムは宇宙環境の影響により特性変化・劣化を受けることが知られているが、軌道上試験・地上模擬試験の結果には不整合が報告されている。さらに、これまで考慮されてこなかった窒素分子の同時衝突が、材料劣化に大きな影響を与えることが明らかにされつつある。本研究課題ではレーザーデトネーション型原子状酸素環境模擬実験装置を用いてポリイミドを基準材料としている現状の国際基準の不完全性を明確化し、科学的に根拠のある新基準の確立・提案を目指すことを目標としている。一般に電気的に中性な原子ビームの正確なフラックス測定は困難であり、原子状酸素に対してはASTMでも便宜的にポリイミドのエロージョン量から評価する手法が推奨されているが、その値が信頼できないことが全ての不整合問題の発端である。そこで国内では本研究グループの装置にのみ取り付けられている原子線飛行時間（TOF）計測システムを用いて、TOFスペクトルの面積強度等から原子状酸素照射量の多角的評価を実施し、ポリイミド質量減少量と相互比較することにより原子状酸素フラックスを絶対評価する手法を確立することを目標にしている。FY2019-2020年度には上記手法に対する検証を行うとともに、超低高度衛星SLATSのフライトデータの詳細解析を実施した。FY2021には前年までの検討結果に基づき、ポリイミドの反応効率の環境依存性を明確化するためのDual-PSV法でのArビームの同時照射効果実験を実施すると共に、SLATSフライトデータ解析における誤差要因の解析を実施した。その結果、地上実験ではビーム中の高エネルギーアルゴン分子の存在比率に対してポリイミド劣化速度が線形的に増加し、SLATSフライトデータとも整合性のある結果が得られた。これによりポリイミド基準による材料劣化量検証の問題点と主原因が確認された。


• Molecular scattering dynamics at hyperthermal velocities and its impact on low drag satellite

  田川 雅人, 横田 久美子, 岩田 稔

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2019 - Mar. 2022

  レーザーデトネーション型原子状酸素ビーム装置は軌道上における原子状酸素と衛星表面の衝突速度を地上で再現できる唯一の方法である。本研究では国内で申請者のみが保有する3式のレーザーデトネーション装置の1台に固体表面で散乱された原子状酸素の検出装置を新規に追加し、その角度分散を計測する簡易的なシステムを構築する。本研究ではこれまでの材料劣化研究の成果を活用し、水晶振動子マイクロバランス（QCM）、あるいは電離真空計を散乱原子状酸素の検出器として採用する。Agあるいは炭化水素薄膜をコーティングしたQCMは原子状酸素センサーとしての実績が豊富で最も低リスクで目標が達成できる可能性がある。試料への入射する原子状酸素ビームをスキマーによって絞り、入射角を可変できる試料台と、試料周りに回転可能なQCMセンサーを設置することで原子状酸素の散乱分布計測という目的が達成できる。フルスペックの質量分析管システムに比較すると1/10以下の予算で目的を達成できる。FY2019年度にはシステム設計を実施し、FY2020年度には電離真空計をセンサーとする散乱実験装置を完成させ、システム評価を実施した。その結果、試作した散乱実験装置は分子線散乱分布を5度以下の分解能で測定可能であることが実証され、分子線散乱DSMC計算に対する検証実験に十分使用できることが確認された。本装置で実測した分子散乱分布をDSMC計算のリファレンスに適用できれば、超熱速度領域のDSMC計算結果に実験的な裏づけを与えることができるとともに、低大気抵抗衛星設計に関する基本的設計指針を得ることができるものと期待される。


• Atomic oxygen-induced erosion of fluorinated polymers in LEO: its collapse and new mechnism

  Yokota Kumiko

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory), Grant-in-Aid for Challenging Research (Exploratory), Kobe University, Jun. 2018 - Mar. 2022

  It has been widely believed that material degradation in LEO is due to atomic oxygen collision. However, ground based-simulation could not duplicate FEP erosion in LEO. This research proposed a new hypothesis that FEP is eroded mainly by N2 collision in LEO. We performed ground-based experiment using AO+Ar beam which simulates simultaneous AO and N2 collision. It was discovered that FEP is eroded much more than that of hydrocarbon in AO+Ar exposure condition. Since the erosion of hydrocarbon is accelerated by the simultaneous Ar (or N2) collisions, the experimental result implies that effect of Ar (or N2) collision on FEP gave even more acceleration on erosion than that of hydrocarbons. The overall conclusion is that FEP erosion in LEO occurs not only by the atomic oxygen collision, but also N2 collision acts as being accelerative or independent.


• 超低高度に適用可能な高強度混合原子線照射技術と「つばめ」搭載超低軌道材料劣化解析

  横田 久美子, 田川 雅人

  日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 神戸大学, Apr. 2018 - Mar. 2022

  世界的に注目されている超低軌道領域の開拓には従来の1000倍にも及ぶ濃密な原子状酸素密度に加えて、高度に応じた窒素分子割合を再現できる地上試験技術の開発が要求さている。そこで本研究では超低軌道宇宙環境模擬技術をベースに本申請者が独自に考案したワンノズル・ツービーム方式によってビームを大フラックス化して、「つばめ（SLATS）」によって得られる世界初の超低軌道上環境曝露試験の結果と比較・解析を実施しようとするものである。具体的には、（１）地上対象実験用原子状酸素と窒素分子の超高強度同時照射技術の開発、（２）SLATS/MDMに搭載した本研究グループの試料劣化状態と地上実験結果を直接比較、（３）ExHAM/MDM2（ISS軌道）及びSLATS/MDMと本研究結果を統合することで高精度な宇宙環境地上実験を実施する上での宇宙環境模擬に関する基盤的技術の獲得、を目指すものである。FY2019には、地上対象実験に用いるワンノズル・ツービームを実現するための、パルスバルブおよびノズルシステムの改造を行い、超熱原子状酸素ビームと超熱アルゴンビームを単一ノズルから発生させることに成功した。一方、フライトデータについてはJAXAから提供されたAOFSデータ解析を実施した。FY2020にはJAXAから提供されたAOFSのデータ解析を継続するとともに、大気モデルから推定したN2密度が材料劣化に与える影響をフライトデータから解析するとともに。新たに提供されたMDM画像データの解析方法についても検討を開始した。


• Feasibility Study on Electron Emission Device using Diamond Semiconductors for Space Applications

  Ohkawa Yasushi

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Japan Aerospace EXploration Agency, Apr. 2016 - Mar. 2019

  Feasibility of electron emission devices using diamond semiconductors for space was investigated aiming at the future application to space debris mitigation technologies. The first major result is that the thermionic electron emission from the diamond semiconductor at low temperature, which was reported in previous studies, was reproduced using a simple heating system. It was also shown that how the low-work-function state degrades by atomic oxygen in the low Earth orbit environment. These results are an important bases for future space applications of diamond semiconductors.


• 高精度テーラーメイド宇宙環境試験のための非熱平衡系多成分高速原子ビーム形成技術

  田川 雅人

  科学研究費補助金／基盤研究(B), Apr. 2014 - Mar. 2018, Principal investigator

  Competitive research funding


• 計算機援用による大気吸入型イオンエンジン用エアインテイクの試作と実験的評価

  田川 雅人

  学術研究助成基金助成金／挑戦的萌芽研究, Apr. 2015 - Mar. 2017, Principal investigator

  Competitive research funding


• レーザープラズマ中における分子解離選択抑制技術と火星エアロブレーキング環境試験

  横田 久美子

  学術研究助成基金助成金／挑戦的萌芽研究, Apr. 2015 - Mar. 2017

  Competitive research funding


• 不活性高質量原子による超低軌道環境における衝突励起材料劣化現象に関する包括的理解

  横田 久美子

  科学研究費一部基金／基盤研究(B)特設, Apr. 2013 - Mar. 2017

  Competitive research funding


• 宇宙利用を支える宇宙材料劣化研究拠点の形成

  田川 雅人

  地球観測技術等調査研究委託事業, 2016, Principal investigator

  Competitive research funding


• 固体反応大気吸入イオンエンジンの超低軌道運用に関するフィージビリティースタディー

  田川 雅人

  学術研究助成基金助成金／挑戦的萌芽研究, Apr. 2013 - Mar. 2015, Principal investigator

  Competitive research funding


• Functionalize of Atomic Oxygen Durability for the Inflatable Structure Materials on Low Earth Orbit

  IWATA MINORU, TAGAWA Masahito, YOKOTA Kumiko

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Kyushu Institute of Technology, 2011 - 2013

  The high atomic oxygen resistance is required on the inflatable structure materials used for the nano-satellite deorbit device. The heat seal property and the durability against ultraviolet ray and charged particle radiation are also required on the inflatable structure materials. However, there is no material having the required properties. In this study, we tried to induce a F, Si, P, and etc. atom that gave the materials the atomic oxygen resistance to a chemical structure of polyimide widely used for space by using post process. As a result, the atom gave the atomic oxygen resistance was detected on the processed materials. Therefore, we could expect the high atomic oxygen resistance on the processed materials.


• 宇宙機の熱設計

  田川 雅人

  研究成果公開促進費／学術図書, 2013, Principal investigator

  Competitive research funding


• 不活性惑星高層大気分子との高速衝突による化学的材料損傷リスク評価

  田川 雅人

  学術研究助成基金助成金／挑戦的萌芽研究, 2011, Principal investigator

  Competitive research funding


• 広領域非回収宇宙環境曝露試験のための高精度地上キャリブレーション

  田川 雅人

  科学研究費補助金／基盤研究(B), 2011, Principal investigator

  Competitive research funding


• 複合宇宙環境下における材料加速劣化シナジー効果発現に関する包括的理解

  横田 久美子

  科学研究費補助金／基盤研究(B), 2010

  Competitive research funding


• 先進量子ビーム励起極表面分析を用いた高精度宇宙環境材料試験技術の開発

  田川 雅人

  科学研究費補助金／基盤研究(B), 2008, Principal investigator

  Competitive research funding


• 宇宙環境シミュレーション技術を応用したデブリフリー極端紫外線発生技術

  田川 雅人

  科学研究費補助金／萌芽研究, 2008, Principal investigator

  Competitive research funding


• 低軌道環境における原子状酸素・紫外線誘起コンタミネーションの脱離・付着特性解析

  横田 久美子

  科学研究費補助金／基盤研究(C), 2007

  Competitive research funding


• 水素と材料の相互作用の実験的解明

  田川 雅人

  2007, Principal investigator

  Competitive research funding


• ＵＬＦ炭素系固体潤滑剤の複合宇宙環境下におけるシナジェスティク効果

  田川 雅人

  科学研究費補助金／基盤研究(B), 2005, Principal investigator

  Competitive research funding


• 複合宇宙環境下でのＦＥＰ－ＭＬＩ劣化に関する定量的地上シミュレーション技術の開発

  横田 久美子

  科学研究費補助金／基盤研究(C), 2005

  Competitive research funding


• ガスフェーズレーザーアブレーションによる反応性高強度超音速原子線の創成

  田川 雅人

  科学研究費補助金／萌芽研究, 2005, Principal investigator

  Competitive research funding


• カーボンナノチューブを中枢材料としたナノトライボロジーの研究

  大前 伸夫

  科学研究費補助金／基盤研究(A), 2005

  Competitive research funding


• Study of the space organic materials erosion in the presence of cosmic my environment - synergy of atomic oxygen and electron beam

  YOKOTA Kumiko, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 2003 - 2004

  Polyimide is one of the most widely used polymers as spacecraft organic materials. Also, polyimide has been used as a reference material to measure the atomic oxygen fluence in LEO. Erosion properties of polyimide by hyperthermal impact of atomic oxygen need to be clarified under various synergistic exposure conditions for an accurate fluence measurement. In this study, the effect of surface charging and temperature on the atomic oxygen-induced erosion of polyimide was studied. The experimental results obtained are listed below. (1)The erosion rates of polyimide were not altered by bias voltages up to ±1000 V under 4.8 eV atomic oxygen exposures. In contract, 20 % increase of polyimide erosion rate was observed by 1.1 eV atomic oxygen beam exposure. It was thus, confirmed that the effect of surface charging on the erosion of polyimide depends on the transrational energy of impinging atomic oxygen. (2)The activation energies of polyimide erosion were calculated to be 10^<-4> eV for 5.0 eV atomic oxygen beam, whereas 10^<-2> eV for 1.1 eV atomic oxygen beam at the temperature range between 253 and 393 K. Presence of the translational energy effects on the temperature dependence of polyimide erosion were experimentally verified. These results of this study contribute to establish the database of spacecraft polymeric materials.


• Surface energy control of polymeric materials for contamination elimination in space environment

  TAGAWA Masahito, YOKOTA Kumiko

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 2002 - 2004

  The surface modification of polymeric materials by using hyperthermal atom beam was made in order to control contact angles of water relevance to contamination in low Earth orbit space environment. Two types of atom beam were currently used for a surface modification, i.e., atomic oxygen and atomic fluorine with translational energies ranging 5 to 10 eV. The translational energies in this range became available after laser detonation-induced beam formation technology was established for space environmental simulation purpose. In the present study, we used this new technology to control the surface free energy of polymers. This new technology also allows us to make low-temperature, damage-free surface modification without any charge-induced problems. From the experimental results obtained in this study, it was confirmed that the oxygen and fluorine concentrations increased with beam exposures. The formation of CF, CF_2 and CF_3 bonds were detected by X-ray photoelectron spectroscopy (XPS) when atomic fluorine beam was used to modify the surface, whereas carbonyl and carboxyl groups were formed when a polymer surface was exposed to atomic oxygen beam. It was demonstrated that the advancing contact angles of water both at polyimide and low-density polyethylene could be tunable between 60 and 135 degree by using this technique without major change of surface roughness. The capability of pattern formation of micro-scale flow channel at polymer surfaces using metal masks demonstrated the capability for avoiding contamination on polymer surfaces using this technique.


• カーボンオニオンの創製とナノトライボロジー特性の発現

  大前 伸夫, 田川 雅人, 保田 英洋

  日本学術振興会, 科学研究費助成事業, 萌芽研究, 神戸大学, 2002 - 2003

  気相あるいは固相からの炭素材料の創製に関しては、フラーレンならびにナノチューブには多大の関心が寄せられているが、それらに加えてグラファイトがナノメートルサイズの球に近いタマネギ構造となったカーボンオニオンが存在することが明らかになってきた。これらの先進炭素材料の表面は良好なトライボロジー特性を有するグラファイト層で覆われており、ナノ構造を有する先進炭素材料のトライボロジー特性が明らかになれば、ナノスケールのトライボロジーに多大の貢献ができるものと考えられる。このような観点から本研究では、カーボンオニオンを中心とした先進炭素材料の創製とそれらのトライボロジー特性の解明を試みた。本研究でプラズマの影響を緩和したプラズマCVD装置を開発することにより、50μmを超える高配向カーボンナノチューブの生成が可能となった。さらに高分解透過電子顕微鏡(HRTEM)でナノダイヤモンド微粒子をその場観察しながら、300kVの高電圧電子線を照射し、ナノダイヤモンド微粒子が、カーボンオニオンに構造変化することを見出した。HRTEM観察の結果、この構造変化にはナノダイヤモンド微粒子径の閾値が存在し、粒子径が5nm以下ではカーボンオニオンとなるが、それより大きなナノダイヤモンド微粒子は明確な構造変が生じなかった。さらにカーボンナノチューブのトライボロジー特牲を研究した結果、一般的にべースオイルとして用いられているポリアルファオレフィン(Polyalphaolefin : PAO)中では、摩擦係数が0303と極めて小さな値であった。カーボンオニオンは良好な耐磨耗性を示すことも明らかとした。


• Development of low-damage low-temperature surface modification technique using laser detonation-induced broad atom beams

  OHMAE Nobuo, YOKOTA Kumiko, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 2000 - 2002

  This study aims at developing the new low-damage surface modification technique using laser detonation supersonic atoms beams. It was made clear that the hydrogen-terminated Si (001) surface can be oxidized by 5 eV atomic oxygen beam even at room temperature. This is due to the fact that more than 80 % of the translational energy was transferred from the impinging atom to the surface atom. The overall oxide growth follows linear-parabolic relationship that is similar to that observed high-temperature oxidation of Si. The initial linear growth was governed by the reaction-limit of oxidant, whereas parabolic one was due to volume diffusion inside the oxide film. It was also demonstrated that the surface free energy (or wettability) of polymer could be controlled by atom beam exposures. From the experimental results obtained in this study, potential advantages of the laser detonation supersonic beam-induced surface modification were identified.


• VAN DER WAALS EPITAXY OF THIN C_<60> FILMS ON SEVERAL SUBSTRATES AND THEIR MICROTRIBOLOGICAL PROPERTIES

  OHMAE Nobuo, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 2000 - 2002

  In this study, surface morphology and growth phenomena of thin C_<60> films epitaxially grown on several substrates were studied for nanotribological applications. C_<60> evaporated from the Knudsen-cell passes through a vacuum of 10^<-8> Pa to condensate a film on substrates, heated at 100℃~250℃. The epitaxial growth of C_<60> thin film was monitored by the Reflection High Energy Electron Deflection (RHEED). Surface morphological images of the epitaxially grown C_<60> films on several substrates were obtained using an atomic force microscope (AFM). From this in-situ analysis with RHEED, it has been found that the C_<60> on MoS_2 substrate makes an epitaxial growth with the lattice spacing of 1.0nm at the substrate temperature of 150℃, which exactly is the spacing of bulk C_<60>. The size of the domain of C_<60> thin film became large at an increased substrate temperatures. Thin C_<60> films with van der Waals epitaxy showed characteristic triangular domain. This result coincides well with the mirror-symmetrical growth of C_<60> films analyzed by RHEED. For H-terminated Si(001) substrate, an epitaxial growth was not found. Cone-like islands with a diameter and a height of several tens nm were formed on H-terminated Si(001) substrate.


• エキソ電子放射を利用したシリコン表面再構成過程の動的観察

  大前 伸夫, 横田 久美子, 田川 雅人

  日本学術振興会, 科学研究費助成事業, 萌芽的研究, 神戸大学, 2000 - 2001

  本研究は半導体用結晶成長技術により培われてきたWell-Defined表面の作製技術を用いて、エキソ電子を初めとする固体表面からの電子放射現象を詳細に解析し、エキソ電子あるいはイオンに関する基礎科学的な貢献を目指すと同時に、新たな表面モニタリング法の開発も視野に入れた研究を行おうとするものである。申請2年目にあたる本年度は電子検出器の高感度化、温度測定の精度向上を図ることにより、Si(111)清浄表面からのイオン放射信号を明確に捕らえる事に成功した。本年度に得られた結果を以下に示す。 (1)RCA洗浄により清浄化した水素終端Si(111)の可逆的表面再構成温度である800℃で非定常のイオン放出を確認した。しかし他の表面再構成温度やSi(100)試料を用いた実験ではイオン放出信号を捕らえることはできなかった。 (2)観察された非定常イオン放出量は試料の冷却速度に依存しており、大きな冷却温度の場合にイオン放出量が増大することが示された。 (3)ケルビンフォース顕微鏡観察の結果から、この温度域での7x7から1x1への表面再構成にも冷却速度依存性が観察され、大きな冷却速度では熱平衡に達しない7x7の領域が再構成温度以下でも存在することが確認された。 以上の結果から、表面再構成時のイオン放出については、試料を急冷することにより表面再構成時に熱的な平衡状態に達することなく常温まで7x7構造が維持され、そのエネルギーの緩和過程としてイオン放出が生じるものと解析された。また、電子状態計算から、表面原子構造とエキソ電子放射の関連性を明らかにし、酸素吸着ならびに表面のステップの存在がエキソ電子放射現象に重要な役割を果たしていることが、計算の結果示された。


• 原子状酸素と高分子材料の表面反応:宇宙実験結果とin-situ地上実験結果の比較

  田川 雅人

  日本学術振興会, 科学研究費助成事業, 奨励研究(A), 神戸大学, 1999 - 2000

  本研究は原子状酸素を照射した高分子表面が大気曝露を受けない宇宙空間では実際にどのような状態にあるのかを明らかにする事を研究目標とし、原子状酸素照射後の高分子の表面状態を大気曝露前後で比較し、宇宙実験サンプルへの大気曝露の影響を明らかにしようとするものである。試料としては代表的な宇宙用高分子であるポリイミドを選び、レーザーデトネーション型原子状酸素発生装置を用いて作成した超熱原子状酸素ビームを試料表面に照射し、大気曝露前後での表面状態の変化をX線光電子分光法を用いて検証した。実験の結果、原子状酸素照射後のポリイミド表面は大気曝露を行わない場合には酸素濃度が増大し、またX線光電子スペクトルの形状も照射前と大きく変化したが、大気曝露後は徐々に酸素濃度が減少するとともにスペクトル形状の変化も小さくなり、曝露前の表面状態に戻ってゆくことが明らかになった。ClsX線光電子スペクトルにおいては、大気曝露前にはカルボキシル基に起因するピークが大きく、多量の原子状酸素が化学吸着していることが示された。本実験で得られた大気曝露後のスペクトルは宇宙実験の結果得られているスペクトルと酷似しており、宇宙実験でサンプルを地上に回収後に得られたXPSスペクトルは大気曝露の影響を強く受けており、実際の軌道上での表面状態を反映していないことが明らかになった。また、水晶振動子マイクロバランス上に形成したポリイミド薄膜の質量変化を原子状酸素ビーム照射中にin-situに測定したところ、原子状酸素照射直後には、一旦、質量増加が観測された後に定常的な質量減少が観測された。コンピューターシミュレーションの結果より、90%以上のガス化反応は酸化された表面で生じていることが示唆され、ポリイミド表面の酸化プロセスがLEOにおけるポリイミドのエロージョンを理解する上で重要であることが示された。


• マイクロサテライトにおけるトライボロジー技術と宇宙環境からの影響評価に関する研究

  田川 雅人, 太田 斉, 大前 伸夫, 志村 考功

  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 1998 - 2000

  本研究は宇宙開発におけるトレンドであるマイクロサテライトに与える5eV原子状酸素照射の影響を評価するために、原子状酸素を照射した二硫化モリブデン単結晶およびスパッタ膜のトライボロジー特性の評価法を確立するとともに、二硫化モリブデンスパッタ膜のマイクロトライボロジー特性の評価を行ったものである。これまで二硫化モリブデンのスパッタ膜を試料としたマクロトライボロジーの実験結果では、数回の摩擦により酸化物層(MoOx)が表面から除去されるため、大きな初期摩擦力を記録した後に原子状酸素照射前の定常状態に回復する現象が観察されていた。しかしながら、この現象には摩擦トラック形成の掘起し効果が重畳されるため、これまで厳密な計測は困難であった。本研究ではトライボロジー特性のin-situ測定を行うこと似より、この問題を解決し、二硫化モリブデンに対する原子状酸素の効果を初めて明らかにできた。実験の結果からは、摩擦係数はスタートアップ時においても定常状態においても原子状酸素照射量に比例して増加してゆくことが観察され、フルーエンス依存症があることが初めて示された。1x10^<18>atoms/cm^2の原子状酸素を照射した後には、初期摩擦力は定常状態における摩擦力の2.5倍の値を示し、二硫化モリブデンスパッタ膜に対しては原子状酸素照射の影響が極めて大きいことがわかった。その原因は、硫黄原子がSOとして表面から脱離し失われること、モリブデンは酸化しMoO_3を形成するためであることが確認された。また、有機バインダーとして用いられるポリイミドについては原子状酸素照射後には大気曝露することで、酸化状態からの回復効果が生ずることが確認され、ポストプロセスでの評価には限界があることが示された。


• Research and Development of Ground Simulation Methods for Spacecraft Environment, and Degradation Experiments of Spacecraft Materials

  TAHARA Hirokazu, OMAE Nobuo, TAGAWA Masahito, YASUI Toshiaki, SETSUHARA Yuichi, MIYAKE Shoji

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka University, 1997 - 1999

  A ground facility was developed for simulation of material and space plasma interaction and for study of spacecraft charging and discharge phenomena. The plasma simulator consisted of a vacuum tank, two turbo-molecular pumps and an electron cyclotron resonance plasma source of a magnetic-field-expansion plasma accelerator. Oxygen, nitrogen and argon plasma properties were measured. The simulator was found to have a high potential for ground tests. Using the simulator, the structure of an ion sheath created around a high voltage solar array and the degradation of surface materials near the array due to high energy ion bombardment were investigated. A negatively biased plate was exposed to oxygen plasma flow. The ion current and the plasma potential distribution were found to be intensively changed by the biased voltage and the attack angle, particularly a scaling parameter derived from the one-dimensional ion sheath theory. Furthermore, in order to examine the influences of ion bombardment on chemical structures of spacecraft surface materials, polymer films of polyimide BPDA-PDA Kapton, located on the biased plate, were exposed to oxygen plasma flow. The XPS analysis showed that an addition reaction of oxygen atoms or ions at wake condition was negligible compared with that at ram condition because of a smaller ion flux. Consequently, the addition reaction and a desorption of structural components were found to occur by ion bombardment. They are expected to cause the decrease in performance of spacecraft thermal control. Furthermore, in order to understand the relaxation of spacecraft charging by plasma flow, i.e., plasma contactor operation, Kapton and Teflon FEP films negatively charged by exposure to high energy electron beams and metal plates in series with negatively charged condensers were exposed to argon plasma flow. Negative charging was rapidly relaxed, and the attack angle influenced the time variation of the neutralization current.


• トンネル電流プローブを用いた真円度・円筒度のナノメータ計測

  大前 伸夫, 田川 雅人

  日本学術振興会, 科学研究費助成事業, 萌芽的研究, 1997 - 1998

  走査プローブ顕微鏡法(Scanning Probe Microscopy;SPM)を回転体の測定に適用した新しいコンセプトの真円度測定法の開発研究を行った。研究室に現有しているタリロンド真円度測定機を改良しただけではその分解能に限界があることが検証されたので、空気軸受けを用いた測定システムを新たに設計、製作した。また、トンネル電流を検出する走査トンネル顕微鏡(Scanning Tuneling Microscopy;STM)モードではチップのクラッシュが多発し、その不安定性が露呈したため、原子間力顕微鏡法(Atomic Force Microscopy;AFM)に変更してナノメータオーダーの真円度測定を目指した。剛性や吸振動性を考慮して、位置決め精度としてサブミクロンの精度を有する万能測長機上に各ユニットを組み上げた。基本構成要素は、(1)回転テーブル(空気軸受け,プーリー,ステッピングモーター)、(2)原子間力を計測するためのチップとトライポット、(3)レーザーフォトダイオードと四分割フォトディテクター、(4)ピエゾ素子駆動による測定物センタリング装置である。AFMを含めてすべての測定ユニットはパーソナルコンピュータによって、駆動、制御されている。測定は市販のAFMを管理している実験室雰囲気とした。SKH51のピンゲージ(0.1φ)をめのうのホルダーに装着しピエゾ素子を逐次駆動させてセンタリングを行った。数rpmまでの回転数でテーブルを操作したところ、回転に起因するリード線からの微弱な電磁ノイズが発生が認められたが、これは回転数を下げることとコードレス化を考えることで解消するものと思われる。また、ディテクターの検出感度に多少の問題が残されているものの現在のところ50nmにせまる検出感度が得られている。本装置はプロトタイプの域を出ないが、操作性を向上させれば真円度、円筒度をナノメータオーダで測定する可能性を十分に示唆することができたものと考えられる。


• 低地球軌道上の原子状酸素と炭素/高分子系宇宙用材料の反応に関する原子オーダー解析

  田川 雅人

  日本学術振興会, 科学研究費助成事業, 奨励研究(A), 大阪大学, 1997 - 1998

  本申請においてはlaser breakdown型原子状酸素発生装置の特徴を生かして、構造材として機体各部に広範に利用されている炭素系材料のモデル材料として熱分解黒鉛(HOPG)を選び、原子状酸素との反応を研究室に現有の超高真空対応走査トンネル顕微鏡(STM)とX線光電子分光装置(XPS)を用いてin-situ観察を試みるものである。本研究の結果、5eVの運動エネルギーを有する原子状酸素がHOPG基底面と反応する場合には、STM像においてprotrusionが観察された。これは反応サイトにおいて炭素原子が気化反応で失われ、ダングリングボンドに酸素原子が吸着したために生じた、局部的な電子状態の乱れに起因するものと思われる。このprotrusionの密度は原子状酸素のフルーエンスと比例関係にあり、その傾きから反応確率は10^<-3>程度であることが明らかになった。この値はこれまでスペースシャトルを使って宇宙での質量減少から計算された原子状酸素とグラファイトの反応確率(0.13)より2桁小さい。これは原子状酸素のフルーエンスが大きくなると観察されるhillock like structureにより、その斜面ではグラファイトのプリズム面が現れることから、、反応の進行しやすいプリズム面での反応が支配的になるためであると考えられる。また、XPSの結果からは原子状酸素のフルーエンスが約4x10^<17>atoms/cm^2で表面酸素量は飽和値(0.94)に達し、ほとんどが化学吸着状態であることも確かめられた。これにより、steady-stateな原子状酸素とグラファイトの反応系ではグラファイト上の吸着酸素の影響を考慮する必要があることが示された。


• Development of the Angular Resolved Reflection High Energy Electron Diffraction and the Electron Impact Mass Spectroscopy for the Studies of Three Dimensional Structure of Surfaces

  OHMAE Nobuo, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 1997 - 1998

  Angular resolved reflection high energy electron diffraction (AR-RHEED), which works in an extreme vacuum of 10^<-8>, has been designed and developed to study three dimensional structure of solid surfaces. The function and reliability of this AR-RHEED has been examined by using molybdenum disulfide (MoS_2) single crystal (0001), and clear streak patterns were obtained at every incident angles. Molecular beam epitaxially (MBE) grown C_<60> films on MoS_2 were prepared and analyzed by AR-RHEED.Superlattice structure of MBE grown C_<60>. with the van der Waals epitaxy, has been obtained. AR-RHEED showed that the MBE grown C_<60> had very smooth surface geometry from the onset of nucleation. The lattice constant of C_<60> is 1 nm, and thus AR-RHEED has an enough resolution to identify sub-nanometers. Surface structure of computer hard disks was tested for practical applications. Halo rings both from PFPE lubricant and from amorphous carbon were recognized. Due to the thickness of carbon films (l0nm), it was unable to detect magnetic storage media (sputtered CO-Cr-Ta-Pt). This implies that the present AR-RHEED is sensitive to surface. The detection of desorption mass spectroscopy of gases was attempted. However, to quantitatively identify F, C, 0 etc., re-design of pole piece of Q-mass was needed. Use of e-beam of the AR-RHEED as an energy loss spectroscopy required EELS spectrometer.


• Development of room-temperature oxidation method of Si due to pulsed hyperthermal atomic oxygen beam

  UMENO Masataka, SHIMURA Takayoshi, TAGAWA Masahito, OHMAE Nobuo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka University, 1997 - 1998

  This project dealt with the new method for room-temperature oxidation of Si wafers "using pulsed-hyperthermual atomic oxygen beam. A broad-. pulsed-, hyperthemial (5eV) atomic oxygen beam, generated by the laser-induced detonation phenomenon of oxygen gas, was applied to formation of thin oxide films on the Si (001) surface. It was clearly observed that the hypertherma.l beam can form thin oxide film (<5 nm) even at the room temperature. This is the thickness can be applied for the next generation ULSIs. The thickness of the oxide film depends on the temperatute and the atomic oxygen flux. It was also observed that the growth of oxide film obeyed the parabolic law. This was confirmed by the in-situ thickness measurement of the oxide film using X-ray photoelectron spectroscopy (XPS) which indicated the linear relationship between oxidation time versus thickness_2. This result clearly showed that the growth mechanism was rate-limited by the diffusion of atomic oxygen. It is, however, measured that the activation energy of diffusion of atomic oxygen in the SiO_2 film was as low as 0.15eV.The activation energy of diffusion of atomic oxygen in the SiO_2 film measure in the out-of-glow region of microwave- generated oxygen plasma was reported to be 0.5eV, and that of molecular oxygen in the thermal oxidation was 1.2eV.The low activation energy on diffusion of atomic oxygen in the SiO_2 film may include the inverse diffusion of interstitial Si atoms which is generated high compressive stresses applied at the Si/SiO_2 interface. In order to reduce such high interfacial stresses, it would be effective to use the premix gas of oxygen with small amount of fluorine.


• Synergistic effect on spacetribology in the low earch orbit

  OHMAE Nobuo, SHIMURA Takayoshi, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka University, 1996 - 1997

  The purpose of this project is to clarify the synergistic effect of atomic oxygen (AO) and the other environmental factors, such as ultraviolet (UV) light or X-rays, in the tribology of satellites used in low earth orbital (LEO) environment. An ion beam type and a laser induced breakdown type AO sources are used in this study to generate energtic AO beam in the laboratory. The research results obtained in this project are as follows : 1. The reaction efficiency of AO with the polyimide film formed by a spin-coating technique is influenced by UV irradiation. Only in the simultaneous irradiation of AO and UV,significant mass loss and CO_2 formation is detected. This research result suggests the photo-assisted chemical reaction of the functional groups such as carbonyl, which absorbs UV light, occurs at the AO bombarded polymer surfaces where carbonyl is formed by AO attacks. 2. When AO hits MoS_2 (0001) surface, So is formed. This volatile product is detected by a quadrupole mass spectrometer during AO beam exposure on MoS_2 (0001). However, the rate of evaporation is not linear with time. This is probably due to the low diffusion rate of AO into the MoS_2 bulk, i.e., reaction is limited only at the very surface region where only limited amount of S is existed. 3. Tribological properties of MoS_2 (0001) is not suffered by AO attack very much. We see maximum 40% increase of initial friction after AO exposure. However, similar effect is also observed even before AO exposure. Certain percentage of this effect is dur to wear track formation. This effect obviously depends on the sliding system and materials' constants. We need to know how much AO influences to the actual sliding component, because the effect of AO on the tribological property of sputtered MoS_2 may be different with single crystal. Further research on this point must be necessary.


• 表面近傍水の疑似固体構造とマイクロマシンのトライボロジーに及ぼす影響

  大前 伸夫, 田川 雅人

  日本学術振興会, 科学研究費助成事業, 萌芽的研究, 大阪大学, 1996 - 1996

  マイクロマシンは今世紀最後の工学革命と言われているが、その動作特性を確実化する上でマイクロトライボロジーが果たす役割は極めて大きい。特にマイクロマシン上に吸着する水分子が微小なメニスカスを形成し、スティクションと言われる相対運動に対する高抵抗を生じさせることは解決しなければならない最大の問題の1つである。本研究では表面近傍に存在する吸着水の構造とその物理・化学的特性を明らかにしてマイクロマシンのマイクロトライボロジーに新知見を与えようとするものである。水分子吸着挙動は水晶振動子マイクロバランス法(QCM)を用いてナノグラム感度で検出し、吸着等温線および吸着熱曲線を算出して考察を加えた。また、ケルビン式を用いてLIGAプロセスによって作製したNiおよびCu表面に存在するマイクロポア(極微小細孔)の分布を求めた。固体表面から3〜4分子層の水は特異な構造を示し、疑似固体ととも考えられる遠距離秩序を保つことが示された。表面に存在するマイクロポアに凝集する水分子のサイズ、LIGAプロセスの際に導入された表面官能基の影響がこのような疑似固体構造と極めて密接な関係にあることが明らかとなった。また、この特異な表面近傍水の存在は各被覆率における接触電気抵抗測定からも確証を得た。さらに、電界イオン顕微鏡(FIM)を併用することにより、Wチップに吸着する水分子を直接イメージし、その吸着サイトや電界下における移動を観察した。水分子吸着は{211}晶帯の大きなテラスから開始し、中央の{011}面へと拡散することが判った。レッジやキンクが優先的な吸着サイトとなり得ること、また、極めて急激な表面拡散を行うことが明らかとなり、現在は水分子の分極と表面近傍水の構造について表面電位の検出も並行して解析をおこなっている。


• Tribology design of micromachine surfaces using the modofication of Fullerene C_<60>

  OHMAE Nobuo, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Osaka University, 1995 - 1996

  The objective of this study was to develop ultrasmooth Fullerene C_<60> films for solving microtribological problems of micromachines. For this purpose, molecular beam epitaxy (MBE) has been used to modify molybdenum disulfide (MoS_2) and highly oriented pyrographite (HOPG) surfaces with C_<60> sublimated from the Knudsen cell. The growth and structure of MBE grown C_<60> have been analyzed in-situ with the reflection high energy electron diffraction (RHEED), and it was found that the C_<60> films show close-packed epitaxial growth with its lattice constant of 1.0nm. Thick film with more than 10 monolayrs also showed smooth surface having fcc structure. Atomic force microscopy (AFM) signified that thick C_<60> films have three-fold symmetry domain structure, which coincides with the results obtained by RHEED.The three-fold domain structure of C_<60> has only been made clear by the research group in Basel University, Switzerland and by this study. Microtribolgical properties of MBE grown C_<60> films have been conducted in an ordinary atmosphere using AFM and friction force microscopy (FFM). Ultralow friction was found for C_<60> films. Thick films with more than 10 monolayrs also showed low friction. Friction coefficients of 0.019 and 0.012 were found for MoS_2 and HOPG substrates, respectively. These values are much lower than those reported by the other three research groups, and this may be caused by the uniform and smooth film structure prepared by MBE.Hydrophobic property against water molecules contained in air was found for MBE grown C_<60> films. This strongly suggests microtribological applications of MBE grown C_<60> films to micromachine.


• Control of electric charge at the interface in the RTO and low temperature oxidation of SOI

  UMENO Masataka, SHIMURA Takayoshi, TAGAWA Masahito, OHMAE Nobuo

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka University, 1995 - 1996

  In the rapid thermal oxidation (RTO) and in the low temperature thermal oxidation of silicon, the incomplete relaxation of intrinsic stress leads to the emission of a lot of interstitial atoms. Consequently, some properties of oxide films and the interface states vary from time to time, which causes it difficult to explain the oxidation behavior with the usual linear-parabolic model. Moreover, in case of the SOI,the complex stress states due to the existence of buried oxide makes it difficult to obtain an oxide layr of good quality. From such a background we constructed the experimental apparatus which was suited for the dynamic analyzes of the thermal oxidation process and established an experimental methodology to study the oxidation mechanism and to control the properties of oxide layr. As a consequence, we obtained many interesting basic data and new knowledge and information in the low temperature thermal oxidation of silicon as follows : 1.The oxidation parameters were analyzed from the oxidation curves measured ith an in-situ ellipsometer, and the difference in the oxidation mechanism between the high and the low temperature thermal oxidation was experimentally verified. 2.It was found that the emission of interstitial silicon atoms ruled the oxidation rate. 3.A stress related model for the emission of interstitial atoms was proposed and experimentally confirmed. 4.The orientation dependencies of oxidation rates in varied temperature and oxidation species revealed the roles of intrinsic stress in the oxidation process. 5.The addition of an appropriate amount of NF3 in the oxidizing gas reduced the residual stress in the oxide films and improved the C-V characteristics. 6.By using an X-ray diffraction technique we found different oxide structures depending on the oxidation temperature, species and the wafer orientation.


• 低地球軌道(LEO)上の原子状酸素とポリイミド系高分子薄膜の相互作用

  田川 雅人

  日本学術振興会, 科学研究費助成事業, 奨励研究(A), 大阪大学, 1995 - 1995

  本研究では国内で唯一稼働中のイオンビーム型原子状酸素発生装置を用いて太陽電池パドルや、人工衛星の温度制御材として機体の表面各部に広範に利用されている高分子材料であり、また、STS-8およびSTS-41,46によるフライトテストの結果から、最も原子状酸素による影響を受ける材料の1つと考えられているポリイミド系薄膜に種々の運動エネルギーを有する原子状酸素を照射し、その反応効率や表面反応の差異等についての基礎的なデータを収集するとともに、EOIM-3等を用いて低地球軌道上で得られたデータとも比較検討を行なうことを目的とするものである。 本研究に使用した原子状酸素発生装置はイオンビーム法をベースとして独自に開発されたもので任意の運動エネルギーを原子状酸素に付与出来ることが最大の特徴である。本装置を用いて宇宙用高分子材料であるポリイミド薄膜に種々の運動エネルギーを有する原子状酸素を照射し、その反応効率や表面反応について基礎的なデータを得るためには安定した原子状酸素ビームを長時間にわたり試料に照射する必要がある。そこで本申請で購入したパルスドバルブ(IOTA-1)によりイオン源の動作をより安定させ、ビームの安定化を図った。改良された本装置を用いて、ポリイミド系高分子薄膜に2eV〜50eVまでの運動エネルギーを有する原子状酸素ビームを照射し、反応効率の運動エネルギー依存性についてのデータを取得した結果、反応レートは運動エネルギーに極めて敏感であること、また、紫外線の同時照射がポリイミドの質量減少に大きく影響していることが明らかにされた。また、宇宙環境に最も近い条件である、5eVの原子状酸素ビームと紫外線の同時照射を行った場合、そのエロ-ジョンレートはスペースシャトルを使ったフライト実験の値(EOIM-3)とほぼ一致することが明らかになった。さらにX線光電子分光法(XPS)の解析結果からはポリイミドを構成しているPMDAとODAの構造のうち、PMDAの部分での劣化が生じていることが推測され、ノリッシュタイプ1と呼ばれる光化学反応が生じて、ポリイミドの劣化が加速されている事が示唆された。これらの実験結果のうち、PMDAの部分でポリイミドの構造が破壊されるという事実は、EOIM-3によるフライトデータの解析結果やNASA-JPLでの実験結果とも一致し、また、紫外線による質量減少の増大はロシアの宇宙ステーション“ミール"の実験結果とも符号する結果である。このように、本実験で得られた結果はポリイミドに対する宇宙環境効果を理論的に説明できる極めて優れたものであると言うことが出来る。


• 電界刺激エキソ電子放射(FSEE)に関する研究

  梅野 正隆, 田川 雅人, 大前 伸夫

  日本学術振興会, 科学研究費助成事業, 重点領域研究, 大阪大学, 1995 - 1995

  本研究は申請者らが世界で初めて実験的検証を行った金属からのトンネル効果によるエキソ電子放射(電界刺激エキソ電子放射:FSEE)に電界イオン顕微鏡(FIM)、電界放射顕微鏡(FEM)という実空間で原子オーダーの空間分解能を有する表面測定技術を組み合わせることにより、トンネル効果によるエキソ電子放射のメカニズムを解明し、その応用に新たな知見を得ることを目的としている。FSEEは通常のエキソ電子放射と同様に表面欠陥、吸着分子、不純物の偏析などの要因が複雑に絡み合って起こる複合的な電子放射現象であると考えられることから、これまで省みられていなかった乱れのある表面の電子状態、およびこのような表面からのトンネル効果による電子放射現象に新たな理解を付け加えることができるものと考えられる。 本年度は本重点領域研究のご支援を頂き、研究室現有のFSEE実験装置に冷却CCDカメラを新たに装着し、微弱なFSEE像を増幅し直接デジタル情報としてコンピューターに入力するシステムを組み上げることに成功した。そしてデジタル化したFSEE像の画像解析を行なうことにより、FSEEの放射サイトを原子オーダーで同定することに成功した。また、Arイオンによるスパッタリングを行ったWチップのFSEE、FIMならびにFEMによる試料同一箇所の原子オーダー観察の結果、FSEEの放射は表面欠陥の分布に強く依存していること、原子オーダーで正常な表面からは観察されないこと、などが明らかになった。また、FSEEの放射メカニズムに関する考察からは、Wチップに関してもA1チップと同様に二過程モデルが適用できることが明らかになった。しかしながら、一部の実験データは二過程モデルではFSEEの放射特性を説明しきれないことから、トラップ準位のエネルギー分布を考慮に入れた修正二過程モデルを提案し、特に低純度試料からのFSEE放射特性を説明できることを示した。


• 電界刺激エキソ電子放射(FSEE)の研究

  梅野 正隆, 田川 雅人, 大前 伸夫

  日本学術振興会, 科学研究費助成事業, 重点領域研究, 大阪大学, 1994 - 1994

  FSEE像と吸着ガスの関係を調べるため、主にWについてFSEEの精密な測定を行った。その結果WのFSEEもAlと同様トラップ準位からのトンネル効果によること、エキソトラップの形成にはガスの物理吸着が主に寄与すること、さらにエキソトラップの密度はWの表面原子密度と同程度であることが結論され、今後STM-STSにおける影響についての検討が必要となる。WではAlに較べ3桁以上強いFSEEが観測されるが、同時に3倍以上強いFEが重畳するので、エミッション像から画像処理により両者を分離してFSEE像を得た。FSEE像の解析からは、FSEEもFEと同様に{111}近くの仕事関数の低い面で生じることが認められた。さらにFIM像との対比から、粒界等の格子欠陥の位置で強いエキソエミッションが生じることが分かり、欠陥起因のエキソ放射機構を直接確めることができた。FIMにより清浄表面を確認した後、N_2およびO_2吸着によるFSEE像とFE像の変化を調べたところ、ガス吸着により仕事関数の増加する結晶面からの放射は両者とも減少することが分かった。このことは2過程モデルにおいて、励起確率とトンネル透過係数の何れもが仕事関数の増加と共に減少することから説明された。


• Study on Surface Interaction between Atomic Oxygen and MoS_2 and Ultra Low Friction (ULF) Using Their Recombination PRocesses

  OHMAE Nobuo, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Developmental Scientific Research (B), Osaka University, 1993 - 1994

  The atomic oxygen generator/ultra-high vacuum tribometer/Auger emission spectrometer has newly been designed and manufactured, and tribolocal properties of single crystal, sputtered, and organic binded MoS_2 have been investigated. In order to simulate the environment in low earth orbit, the energy and flux of atomic oxygen beam were set at 5 eV and 5.5*10^<15>atoms/m^2・_S. For MoS_2 singlecrystal, friction coefficient increased from the initial value of 0.03 to larger values, and after 5 hours'irradiation, the friction coefficient over 2.0 resulted. None of S and Mo Auger peaks were identified from that surface, and transfer of Ti, which is the mating material to MoS_2, was detected. Similar tendency was recognized for sputtered MoS_2, and it was found by AES and XPS that the increased friction is caused by the formation of MoO_3, MoO_2, and MoO_. Though organic binded MoS_2 showed a relatively high friction coefficient of 0.05 before exposure to atomic oxygen, the friction coefficient after 5 hours' exposure to atomic oxygen was low at 0.1. For organic binded films, C and O incorporated in polyamide-imide may have a possible suppressing action from the gasification of S.The oxydized layr for organic binded MoS_2 was thin, so that more stable tribological properties of organic binded MoS_2 than those of single crystal and sputtered MoS_2 can be caused by less gasification of S.By designing a sleeve near the MoS_2 specimen, a recombination of atomic oxygen into molecular state was attempted. Friction experiments at this environment showed a good value of 0.01. In addition, an introduction of CO gas enhanced the ultra low friction, but the irradiation of UV increased the friction. Laser desorption spectroscopy inside the AES chamber detected SO_3 during exposure to atomic oxygen. It was concluded that the ultra low friction requires the stabilization of S on MoS_2 surface and the mesoscopic analysis of surface integrity of MoS_2 crystal.


• マイクロメカニクスにおける水分子の吸着と表面相互作用

  田川 雅人

  日本学術振興会, 科学研究費助成事業, 奨励研究(A), 大阪大学, 1993 - 1993

  Niを材料とするLIGAプロセスは高いアスペクト比を持つ微小機械要素を作製できることから、大気中のみならず人体内などの極限環境下でも使用されるマイクロメカニクス作製技術として注目されている。マイクロメカニクス表面にはほとんどすべての動作環境においてH_2O分子が吸着すると考えられるが、これがマイクロメカニクスの運動性にどのような影響を与えるかは、マイクロメカニクスを実用化する上で極めて重要であるにもかかわらず現在まで全く知見が得られていない。本研究では高湿度環境下でのマイコロメカニクスの動作特性を解析するために、QCM法を用いた吸着等温線測定およびレーザーエリプソメトリーで水分子の吸着量をモニターし、Ni深針との相互作用力を測定することにより、H_20分子が存在する系でのマイクロメカニクス表面で生じる現象を解明することを目的とした。本年度の研究実施計画に基づき、まず試料表面の光学定数やH_2O膜厚を同時測定するためのレーザーエリプソメーターを作製し、現有の実験装置に取り付けるための改造を行なった。直線偏光He-Neレーザー発振管ならびに電源(129,780)を備品として、またコンピューターの計算能力を向上させるためのCyrix486倍速CPUボード、エリプソメーターの構成要素である検光子およびその駆動系、光学部品、検出素子、真空用窓、I/Oボード等(729,440)を消耗品として購入した。光学研磨を行なったAu電極の水晶振電動子にH_2O分子を吸着させ、その吸着量をQCM法、ならびにエリプソメーターでモニターしながらTipの凝着特性を調べた。その結果、Tip-試料表面間の凝着にはヘルツの接触面積と吸着水分子層のメカニカスによる効果の両方を考慮する必要があり、吸着水分子層が1〜数分子層の領域で最も機械的運動特性が影響を受けるという結果が得られた。またエリプソメーターで測定した光学定数△はQCM法によって求められた水分子吸着量に対応した変化を示し、水分子吸着層厚を測定する上でのエリプソメトリの有効性が示された。エ プソメトリはQCM法が適用できない温度領域やバルク試料にも適応可能であることから、QCM法と併用することによって幅広い試料表面での水分子吸着を解析することが可能であると思われ、特に理想表面に近い原子オーダーで平坦な表面の解析や凝着モデルの構築に力を発揮するものと期待できる。


• 電界刺激エキソ電子放射(FSEE)の研究

  梅野 正隆, 田川 雅人, 大前 伸夫

  日本学術振興会, 科学研究費助成事業, 重点領域研究, 大阪大学, 1993 - 1993

  エキソ電子放射は原子力プラント等における新しい探傷技術として注目されているが、その放射特性と固体表面との関連性(放射メカニズム)が十分明確化されていないことから実用化には至っていない。一方、電界電子放射の分野においては電界イオン顕微鏡(FIM)や電界電子顕微鏡(FEM)を用いた原子オーダーでの表面解析が行われてきたが、試料がTipに限定されるため、今日までこれらの表面解析手法をエキソ電子放射に応用しようとする試みはなされていなかった。本研究は申請者らが世界で初めて実験的検証を行った金属からのトンネル効果によるエキソ電子放射(電界刺激エキソ電子放射:FSEE)を用いることにより、これら2つの技術の融合を図り、エキソ電子のトンネリング過程による放射メカニズムを解明するとともに、従来法では得られなかったエキソ電子放射の基礎情報を原子スケールの実空間分解能と共に直接得ることを目的としたものである。 本年度は当初の研究計画に従い研究室現有のFSEE実験装置にimage intensifier system(Hamamatsu Photonics V2697U)を組み込み、CCDカメラあるいは35mmカメラでFSEE像を撮影し、パーソナルコンピューター(Macintosh 660AV)上のPhoto shopにより画像処理を行うことにより、微弱なFSEE信号を増幅しFSEE像の直接観察を可能とするシステムを製作した。W-Tipを試料とした実験の結果、本装置は十分な空間分解能を持つことが確認され、同一TipのFSEE像、FIM像、FEM像を撮影することに成功した。これらの一連の実験の結果、AlならびにW-TipからのFSEEには二過程モデルが適用できること、Tip上に吸着した酸素、水素がエキソ電子のトラップサイトを形成していること、FSEE放出量は仕事関数の変化にリニアには対応しないこと、通常の電界放射とは逆の温度特性を持つこと等が確認され、従来のトンネル効果のみでは説明がつかないことが明らかとなった。しかしながら、FSEEの放射確率には明らかにトンネリング過程の寄与と思われる挙動が見られることから、今後吸着ガス分子の影響等も考慮した新たなエキソ電子放射モデルの構築が必要であると思われる。


• Study on Space Tribology Using the Pulsed Oxygen-Atom Source

  OHAME Nobuo, TAGAWA Masahito

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for General Scientific Research (B), Osaka University, 1990 - 1991

  Ground-based facilities for generating atomic oxygen (AOX) are essential to investigate tribology in low earth orbit (LEO), where the space station is to be launched. We have developed a new AOX generator utilizing the decomposition of pulsed oxygen molecule gases into AOX with use of Xe arc flash light. The AOX generator was operated at a vacuum of 10^<-6>Pa, which is the vacuum level in LEO. The kinetic energy and flux of AOX beam were set at 5 eV and 10^<16> atoms/m^2s both of which are the typical values in LEO (500 km). Thus the present AOX generator is able to simulate the LEO environment. Gas breakdown by the Xe arc flash light also was maintained with an auxiliary use of mini-YAG laser. Molybdenumdisulfide, which has been considered as one of the best materials for space tribology, are attacked by AOX. The desorption of sulfur in the form of SO and SO_2 occurred at first, and the formation of molybdenum oxide, primary MoO_3, followed. HOPG graphite also was severely damaged ; C-O and C=O bonds and subsequent carboxyl formation being recognized. Natural graphite showed the disappearance of characteristic shoulder in the carbon-KLL Auger peak, which implies the deterioration of graphite lamellar structure. Friction coefficient as high as 0.2 was found for molybdenumdisulfide exposed to AOX beam. Therefore, the use of molybdenumdisulfide in LEO is not promising. The development of oxide-based solid lubricants is to be needed.

• 外部講師

  市立西宮高等学校

  Lecturer, 理系進路説明会