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Al
(R = La and Pr)Sakoda, Masahito*; Kubota, Kazuhiro*; Tanaka, Shuhei*; Matsuoka, Eiichi*; Sugawara, Hitoshi*; Matsuda, Tatsuma; Haga, Yoshinori
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB011_1 - SB011_4, 2012/12
Times Cited Count：2 Percentile：10.8(Physics, Multidisciplinary)Yamaki, Tetsuya; Kobayashi, Kazuhiro; Asano, Masaharu; Kubota, Hitoshi*; Yoshida, Masaru
Polymer, 45(19), p.6569 - 6573, 2004/09
Times Cited Count：56 Percentile：82.78(Polymer Science)We prepared proton exchange membranes by the 
-ray-induced post grafting of styrene into crosslinked polytetrafluoroethylene (PTFE) films and subsequent sulfonation. The degree of grafting was controlled in the range of 7-75% by the crosslinking density of the PTFE matrix as well as the grafting conditions. Under our preparation conditions, the films at the grafting yield of 
30% were found to produce ion exchange membranes with a homogeneous distribution of sulfonic acid groups. The resulting membranes showed a large ion exchange capacity up to 2.9 meq g
, which exceeded the performance of commercially-available perfluorosulfonic acid films such as Nafion; nevertheless, they appeared to be dimensionally stable in water. These should undoubtedly result from the use of the crosslinked PTFE films as graft substrates and make our ion exchange membranes promising for applications to polymer electrolyte fuel cells.
Yamaki, Tetsuya; Asano, Masaharu; Maekawa, Yasunari; Morita, Yosuke; Suwa, Takeshi; Chen, J.*; Tsubokawa, Norio*; Kobayashi, Kazuhiro*; Kubota, Hitoshi*; Yoshida, Masaru
Radiation Physics and Chemistry, 67(3-4), p.403 - 407, 2003/08
Times Cited Count：76 Percentile：97.02(Chemistry, Physical)no abstracts in English
Inoue, Yutaka; Kobayashi, Kazuhiro; Yamaki, Tetsuya; Asano, Masaharu; Kubota, Hitoshi*; Yoshida, Masaru
Dai-2-Kai 21-Seiki Rengo Shimpojiumu; Kagaku Gijutsu To Ningen Rombunshu, p.257 - 260, 2003/00
We prepared crosslinked fluoropolymer electrolyte membranes for use in fuel cells and then investigated their structural properties by X-ray diffraction (XRD) analysis. The radiation-induced grafting of styrene into crosslinked polytetrafluoroethylene (PTFE) films and subsequent sulfonation enabled us to obtain the electrolyte membrane with a sufficient ion exchange capacity, which exceeds that of the commercially-available film, Nafion. As the crosslinking and styrene grafting reactions proceeded, the size of the PTFE crystallites in the film became smaller, thereby decreasing the film crystallinity. Interestingly, in contrast to Nafion, the resulting sulfonated membranes were found to have high crystallinity.
Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Hayashida, Hirotoshi; To, Kentaro; Yamagishi, Hideshi*; Katagiri, Masaki*; Sakasai, Kaoru; Maruyama, Ryuji; Mizusawa, Tazuko*; et al.
no journal, ,
Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Hayashida, Hirotoshi; To, Kentaro; Yamagishi, Hideshi*; Katagiri, Masaki*; Sakasai, Kaoru; Maruyama, Ryuji; Mizusawa, Tazuko*; et al.
no journal, ,
Yamazaki, Dai; Soyama, Kazuhiko; Miyata, Noboru*; Kasai, Satoshi*; Akutsu, Kazuhiro*; Hanashima, Takayasu*; Kubota, Masato; Aoki, Hiroyuki; Suzuki, Junichi*; To, Kentaro; et al.
no journal, ,
Polarized neutron reflectometry is one of the powerful methods to investigate various phenomena on the surfaces and interfaces of a variety of films with layered structures such as magnetic materials. In this instrument, a two-dimensional position-sensitive neutron detection system consists of multi-wire proportional chamber (MWPC) with helium-3 gas and its data reduction software have been developed for the measurement of off-specular reflectivity and grazing incidence small-angle neutron scattering (GISANS). Each wire signal is read out by amplifier-shaper-discriminator (ASD) individually to meet with demands for a fast counting response and high spatial resolution for the measurement at intense pulsed neutron sources. The pitch between anode/cathode wires is 1.0 mm. The spatial resolution was 1.8 mm. We report characterization results of 2-D MWPC system at BL17 and its applications to neutron reflectivity measurements.
