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Saito, Toru; Okubo, Toshikazu*; Izumi, Keisuke*; Okawa, Yoshinao*; Kobayashi, Norihiro*; Yamazaki, Toru; Kawano, Katsumi; Isono, Takaaki
Teion Kogaku, 50(8), p.400 - 408, 2015/08
Aramid fiber-reinforced plastic (AFRP) has been developed as a structural material that has the advantages of light weight and high strength. In this study, tensile tests were carried out to measure the tensile properties of AFRP rod on the market for reinforcement of concrete at room temperature, 77 K and 4.2 K. Especially at cryogenic temperatures, it is difficult to perform a tensile test of the bar because the specimen slips through the jig grip. To prevent the rod from slipping, tensile tests were carried out with some filling conditions. The applicable and appropriate tensile test conditions were established by modifying the jig grip, treating the surface of the rod and using cryogenic epoxy infill to grip the rod. They were more than 1100 MPa. Additionally, the AFRP rod included a temperature dependence in which the Young's modulus increased as the test temperature decreased. It was confirmed that the Young's modulus increased because aramid fiber was more dominant than epoxy.
Osawa, Takahito; Hatsukawa, Yuichi; Nagao, Keisuke*; Koizumi, Mitsuo; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi; Furutaka, Kazuyoshi
Geochemical Journal, 43(6), p.415 - 422, 2009/00
Times Cited Count：4 Percentile：16.49(Geochemistry & Geophysics)The Cretaceous-Tertiary (K-T) boundary about 65 million years ago records a mass extinction event caused by a bolide impact. K-T boundary clay collected from Stevns Klint, Denmark was investigated in this work. Iridium concentrations of eight clays across the K-T boundary were determined using a multiple 
-ray analysis system after neutron activation. Anomalously high Ir concentrations were detected in five marl samples, with the highest concentration being 29.9 ppb. Four samples were analyzed for all noble gases. No extraterrestrial Ar, Kr, and Xe were discovered in any of the samples, although most of the 
He which was detected was extraterrestrial. Solar-like Ne was observed only in the sample SK4, which had an Ir concentration of 14.3 ppb, indicating the presence of micrometeorites.
Hori, Toshihiko*; Ito, Takashi; Chishiro, Etsuji; Izumi, Keisuke*; Yamazaki, Masayoshi*; Watanabe, Kazuhiko*; Takasaki, Eiichi*; Hasegawa, Kazuo; Yoshikawa, Hiroshi
Proceedings of 27th Linear Accelerator Meeting in Japan, p.255 - 257, 2002/08
no abstracts in English
Okawa, Yoshinao; Kashimura, Shinji*; Murano, Yoshihiro*; Ito, Michio*; Okada, Kenichi*; Izumi, Keisuke*; Tsuchida, Takashi*
Dai-19-Kai Denki Setsubi Gakkai Zenkoku Taikai Koen Rombunshu, p.415 - 416, 2001/00
no abstracts in English
Okawa, Yoshinao; Murano, Yoshihiro*; Okada, Kenichi*; Kawakami, Kunio*; Izumi, Keisuke*; *; Sasaki, Takashi*; *
Heisei 12-Nendo Denki Setsubi Gakkai Zenkoku Taikai Koen Rombunshu, p.315 - 316, 2000/00
no abstracts in English
Izumi, Keisuke*; Iguchi, Masayuki*; Kawasaki, Masaji*; Okawa, Yoshinao*; Oka, Kiyoshi; Yamagata, Ryohei; Koyanaka, Akihiro*
no journal, ,
At penetration parts in radiation controlled areas, such as walls and floors where cables go through, the high-airtight performance is required in order to control the negative pressure of air-conditioning. Moreover, since the cables get deteriorated by radiation, the easy replacement works are indispensable. However, the materials in general use have neither resistance, nor any sheltering performance against radiation. In this research, we have developed radiation-proof materials, to meet both an airtight and a sheltering performance.
Kamikawa, Masaaki*; Izumi, Keisuke*; Kawasaki, Masaji*; Oka, Kiyoshi; Yamagata, Ryohei
no journal, ,
no abstracts in English
Kamikawa, Masaaki*; Izumi, Keisuke*; Takemoto, Jumpei*; Kawasaki, Masaji*; Oka, Kiyoshi; Yamagata, Ryohei
no journal, ,
no abstracts in English
Izumi, Keisuke*; Iguchi, Masayuki*; Iida, Shinji*; Kawasaki, Masaji*; Okawa, Yoshinao*; Oka, Kiyoshi; Yamagata, Ryohei
no journal, ,
no abstracts in English
