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Kato, Masaru*; Muto, Marika*; Matsubara, Naohiro*; Uemura, Yohei*; Wakisaka, Yuki*; Yoneuchi, Tsubasa*; Matsumura, Daiju; Ishibara, Tomoko*; Tokushima, Takashi*; Noro, Shinichiro*; et al.
ACS Applied Energy Materials (Internet), 1(5), p.2358 - 2364, 2018/05
Times Cited Count：13 Percentile：45.56(Chemistry, Physical)Sakamoto, Hiroyuki*; Akagi, Yosuke*; Yamada, Kazuo*; Tachi, Yukio; Fukuda, Daisuke*; Ishimatsu, Koichi*; Matsuda, Mikiya*; Saito, Nozomi*; Uemura, Jitsuya*; Namihira, Takao*; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 17(2), p.57 - 66, 2018/05
Concrete debris contaminated with radioactive cesium and other nuclides have been generated from the accident in the Fukushima Dai-ichi Nuclear Power Plant and there will be generated due to the decommissioning of nuclear power plants in the future. Although conventional decontamination techniques are effective for flat concrete surfaces such as floors and walls, it is not clear what techniques to apply for decontaminating radioactive concrete debris. In this study, focusing on a pulsed power discharge technique, fundamental experimental works were carried out. Decontamination of concrete by applying the aggregate recycling technique using the pulsed power discharge technique was evaluated by measuring radioactivity of aggregate and sludge separated from the contaminated concrete. The results suggest that the separation into aggregate and sludge of the contaminated concrete debris could achieve decontamination and volume reduction of the radioactive concrete debris.
Motokura, Ken*; Fukuda, Takuma*; Uemura, Yohei*; Matsumura, Daiju; Ikeda, Marika*; Nambo, Masayuki*; Chun, W.-J.*
Catalysts, 8(3), p.106_1 - 106_8, 2018/03
Times Cited Count：4 Percentile：9.85(Chemistry, Physical)
resolutionUemura, Takuya*; Kita, Akiko*; Watanabe, Yoshihiko*; Adachi, Motoyasu; Kuroki, Ryota; Morimoto, Yukio*
Biochemical and Biophysical Research Communications, 469(2), p.158 - 163, 2016/01
Times Cited Count：16 Percentile：52.57(Biochemistry & Molecular Biology)Kawamura, Kenji*; Parrenin, F.*; Lisiecki, L.*; Uemura, Ryu*; Vimeux, F.*; Severinghaus, J. P.*; Hutterli, M. A.*; Nakazawa, Takakiyo*; Aoki, Shuji*; Jouzel, J.*; et al.
Nature, 448(7156), p.912 - 916, 2007/08
Times Cited Count：338 Percentile：96.41(Multidisciplinary Sciences)We present a new chronology of Antarctic climate change over the past 360,000 years that is based on the ratio of oxygen to nitrogen molecules in air trapped in the Dome Fuji and Vostok ice cores. This ratio is a proxy for local summer insolation, and thus allows the chronology to be constructed by orbital tuning without the need to assume a lag between a climate record and an orbital parameter. The accuracy of the chronology allows us to examine the phase relationships between climate records from the ice cores and changes in insolation. Our results indicate that orbital-scale Antarctic climate change lags Northern Hemisphere insolation by a few millennia, and that the increases in Antarctic temperature and atmospheric carbon dioxide concentration during the last four terminations occurred within the rising phase of Northern Hemisphere summer insolation. These results support the Milankovitch theory that Northern Hemisphere summer insolation triggered the last four deglaciations.
Mori, Hiroko*; Uemura, Taiki*; Matsuyama, Hideya*; Abe, Shinichiro; Watanabe, Yukinobu*
no journal, ,
Terrestrial neutron-induced soft error has been recognized as a serious reliability problem for microelectronics. An irradiation testing with spallation neutron beam is suitable for evaluation of terrestrial neutron induced soft error rate (SER). The SER measured in neutron irradiation facility is necessary to compensate since neutron beam spectra obtained each facility is different from terrestrial neutron spectrum reported by JEDEC. We provide SER ratio between JEDEC's and facility's as a function of critical charge so as to compensate SER in various devices. The SER ratio was derived from single event upset (SEU) cross-section calculated by a multi-scale Monte Carlo simulation code system PHYSERD (PHits-HYenexss integrated code System for Effects of Radiation on Device). We performed SER testing using spallation neutron beam at three facilities. The deviation among measured SERs compensated by the SER ratio is less than 5%.
Uemura, Takuya*; Kita, Akiko*; Adachi, Motoyasu; Kuroki, Ryota; Morimoto, Yukio*
no journal, ,
no abstracts in English
Fujita, Hiroe*; Yuyama, Kenta*; Uemura, Yuki*; Sakurada, Shodai*; Hu, C.*; Chikada, Takumi*; Oya, Yasuhisa*; Ota, Masayuki; Ochiai, Kentaro
no journal, ,
Tungsten (W) is the candidate for the plasma facing material in D-T fusion reactors. The distribution of defects introduced by neutron irradiation is formed uniformly throughout the bulk, while that by heavy-ion irradiation is concentrated in the shallow region near the surface. Therefore, it is expected that the hydrogen isotope behaviour in neutron irradiated W would be different from that in heavy-ion irradiated W. In this study, the irradiation defects were introduced by Fe
irradiation, fission neutron irradiation and 14 MeV neutron irradiation from D-T fusion reaction. After the irradiation, the deuterium ions (D) implantation was performed and the D retention behaviour was evaluated by thermal desorption spectroscopy (TDS). The experimental results indicate that stable trapping sites would be formed into W by 14 MeV neutron irradiation with lower neutron fluence, on the other hand, only low energy trapping sites will be formed by fission neutron irradiation.
Hasegawa, Takayuki*; Uemura, Masaharu*; Takueuchi, Kazuki*; Kodaka, Takuya*; Fukada, Noboru*; Umesaki, Norimasa*; Fukushima, Sei*; Teraoka, Yuden; Haruyama, Yuichi*; Niibe, Masahito*; et al.
no journal, ,
no abstracts in English
Horiguchi, Kenichi*; Honzawa, Masami*; Nomura, Kai*; Uemura, Yuta*; Motoshima, Takayuki*; Oshino, Yoshiyuki*; Hiroshima, Takashi*; Okabe, Shigeyuki*; Miyara, Masahiko*; Nabana, Ryohei
no journal, ,
no abstracts in English
