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Goto, Aki*; Michishio, Koji*; Oka, Toshitaka; Tagawa, Masahito*; Yamashita, Shinichi*
Langmuir, 39(34), p.11954 - 11963, 2023/08
Times Cited Count：0 Percentile：0(Chemistry, Multidisciplinary)Atomic oxygen (AO) is one of the dominant components of the residual atmosphere in low Earth orbit. AO collides with spacecraft with translational energy of 5 eV, forming nanoscale protrusions on polymeric materials. This study investigated the size of free-volume holes and the layer thickness that interacted with AO for polyethylene (PE), polypropylene (PP), and polystyrene (PS) by positron annihilation lifetime spectroscopy. By the AO irradiation, oxidized layer formed in the surface, and the maximum depth of the oxidized layer for PE and PP were deeper than for PS. The different sizes of free-volume holes would affect the injection depths of AO, resulting in the oxidized layers' thicknesses and surface morphologies.
Tamai, Hiroshi; Matsukawa, Makoto; Kurita, Genichi; Hayashi, Nobuhiko; Urata, Kazuhiro*; Miura, Yushi; Kizu, Kaname; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Kudo, Yusuke; et al.
Plasma Science and Technology, 6(1), p.2141 - 2150, 2004/02
Times Cited Count：2 Percentile：6.49(Physics, Fluids & Plasmas)The dominant issue for the the modification program of JT-60 (JT-60SC) is to demonstrate the steady state reactor relevant plasma operation. Physics design on plasma parameters, operation scenarios, and the plasma control method are investigated for the achievement of high-
. Engineering design and the R&D on the superconducting magnet coils, radiation shield, and vacuum vessel are performed. Recent progress in such physics and technology developments is presented.
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Chujo, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
no abstracts in English
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Cho, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
Times Cited Count：33 Percentile：69.03(Physics, Fluids & Plasmas)no abstracts in English
Omi, Masao; Mimura, Hideaki; ; Fukaya, Kiyoshi; Yonekawa, Minoru; Goto, Ichiro; ; Saito, Junichi; Eto, Motokuni;
JAERI-Tech 96-005, 39 Pages, 1996/02
no abstracts in English
JRR-2 Control Office; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.
JAERI 1027, 57 Pages, 1962/09
no abstracts in English
JRR-2 Critical Experiments Group; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.
JAERI 1025, 62 Pages, 1962/03
no abstracts in English
Goto, Aki*; Tagawa, Masahito*; Michishio, Koji*; Oka, Toshitaka; Yamashita, Shinichi*
no journal, ,
Films of polyethylene, polypropylene and polystyrene were irradiated with AO, and their surface morphologies and free volumes were investigated. Nanoscale protrusions were formed for all sample surfaces with the AO fluences of 
atoms/cm
- 
atoms/cm. The free volumes in the surfaces within 40 nm - 50 nm decreased due to the AO irradiations.
Goto, Aki*; Tanji, Takashi*; Tagawa, Masahito*; Michishio, Koji*; Oka, Toshitaka; Yamashita, Shinichi*
no journal, ,
Atomic oxygen (AO) is a dominant constituent of residual atmosphere in low Earth orbit, it is necessary to evaluate materials' durability against AO before launching but the mechanism for the microstructure formation has not been understood. In this study, we irradiated AO to polymer surface and investigated the change of surface morphologies. The mass losses of irradiated polymers were similar regardless of polymer's type and temperature, however, the formed protrusions became larger and fewer with increasing temperature. This shows that the polymer chains' thermal motions affected the surface morphologies.
Goto, Aki*; Tanji, Takashi*; Tagawa, Masahito*; Michishio, Koji*; Oka, Toshitaka; Yamashita, Shinichi*
no journal, ,
Crystallinity and thermal property were evaluated for polyethylene, polypropylene, polystyrene films, then, they were irradiated with atomic oxygen (AO) and observed by a scanning electron microscope and positron annihilation lifetime spectroscopy. Free-volume holes and thermal motions affected spatial scales for the reactions with AO, determining the sizes and numerical density of formed protrusions.
