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(001)Tsai, Y. H.*; Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kobayashi, Toru; Yamashita, Yoshiyuki*
Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03
Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.
KEK Proceedings 2022-2, p.61 - 66, 2022/11
The balance between oxidative stress and antioxidant activity, which is a defense mechanism against oxidative stress, was investigated in the liver and bladder of wild Japanese macaques captured in Fukushima Prefecture. No significant induction of oxidative stress by exposure to environmental radionuclides after the Fukushima nuclear accident was observed, suggesting that the stress defense mechanism of the organism is activated in some organs.
Yamashita, Keishiro*; Komatsu, Kazuki*; Klotz, S.*; Fabelo, O.*; Fern
ndez-D
az, M. T.*; Abe, Jun*; Machida, Shinichi*; Hattori, Takanori; Irifune, Tetsuo*; Shimmei, Toru*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 119(40), p.e2208717119_1 - e2208717119_6, 2022/10
Times Cited Count：2 Percentile：22.35(Multidisciplinary Sciences)Here we present the first elucidation of the disordered structure of ice VII, the dominant high-pressure form of water, at 2.2 GPa and 298 K from both single-crystal and powder neutron diffraction techniques. We reveal the three-dimensional atomic distributions from the maximum entropy method and unexpectedly find a ring-like distribution of hydrogen in contrast to the commonly-accepted discrete sites. In addition, total scattering analysis at 274 K clarified the difference in the intermolecular structure from ice VIII, the ordered counterpart of ice VII, despite an identical molecular geometry. Our complementary structure analyses robustly demonstrate the unique disordered structure of ice VII. Furthermore, these noble findings are related to the proton dynamics which drastically vary with pressure, and will contribute to an understanding of the structural origin of anomalous physical properties of ice VII under pressures.
Yamashita, Keishiro*; Komatsu, Kazuki*; Ohara, Takashi; Munakata, Koji*; Irifune, Tetsuo*; Shimmei, Toru*; Sugiyama, Kazumasa*; Kawamata, Toru*; Kagi, Hiroyuki*
High Pressure Research, 42(1), p.121 - 135, 2022/03
Times Cited Count：3 Percentile：58.88(Physics, Multidisciplinary)Sasao, Eiji; Danhara, Toru*; Yamashita, Toru*; Hayashi, Joji*
Mizunamishi Kaseki Hakubutsukan Kenkyu Hokoku, (48), p.9 - 19, 2021/05
Petrographic description of tuffs in the Miocene Mizunami Group has been made to offer basic data. This report includes the descriptions of 14 and 4 tuff beds in the Mizunami and Iwamura Groups, respectively. Followings are presented in this report; mineral and heavy mineral composition, shape of volcanic glass, and refractive indices of volcanic glass and plagioclase.
Ikuta, Masafumi*; Niwa, Masakazu; Danhara, Toru*; Yamashita, Toru*; Maruyama, Seiji*; Kamataki, Takanobu*; Kobayashi, Tetsuo*; Kurosawa, Hideki*; Kokubu, Yoko; Hirata, Takafumi*
Chishitsugaku Zasshi, 122(3), p.89 - 107, 2016/03
We carried out mineral composition analysis, morphological classification of volcanic glass shards and refractive index measurements of the glass shards and orthopyroxene from the eruption products from Sakurajima volcano. In this study, refractive indexes of hydrated and non-hydrated parts within each individual glass shard were measured separately. This measurements in consideration of hydration in glass shards made possible distinct discrimination of the pumice samples from the three eruption events of Bunmei, An-ei, and Taisho. Pumice layers in the core samples obtained from the southern part of the Miyazaki Plain were also identified as the Sakurajima-Bunmei tephra by the above mentioned analyses, and also by the data of radiocarbon dating for coaly materials included in the pumice layers. Occurrences of the pumice layers suggest that the Sakurajima-Bunmei tephra could have reached the southern part of Miyazaki Plain as pumice falls.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Tanno, Takeo*; Sanada, Hiroyuki; Sato, Toshinori
JAEA-Research 2013-040, 51 Pages, 2014/03
JAEA-Research-2013-040.pdf:6.86MB
For the research and development about high-level radioactive waste disposal, it is important to evaluate the mechanical stability of the excavation and the long-term behavior of in situ rock. However, from the limited information such as the bowling core before the excavation, it is difficult to evaluate the mechanical properties of in situ rock containing cracks. For this reason, evaluation of rock properties based on Specific Energy using mechanical data from an excavation machine is carried out. This report describes the results of the joint research carried out in FY 2010 to FY 2012.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo
Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.247 - 248, 2013/08
no abstracts in English
Fujii, Hirofumi*; Hara, Kazuhiko*; Hashimoto, Shugo*; Ito, Fumiaki*; Kakuno, Hidekazu*; Kim, S.*; Kochiyama, Mami; Nagamine, Kanetada*; Suzuki, Atsuto*; Takada, Yoshihisa*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2013(7), p.073C01_1 - 073C01_20, 2013/07
Times Cited Count：26 Percentile：76.73(Physics, Multidisciplinary)Fujibuchi, Toshio*; Kawamura, Taku*; Yamanashi, Koichi*; Hiroki, Akihiro; Yamashita, Shinichi*; Taguchi, Mitsumasa; Sato, Yuichi*; Mimura, Koichi*; Ushiba, Hiroaki*; Okihara, Toru*
Journal of Physics; Conference Series, 444(1), p.012089_1 - 012089_4, 2013/06
Times Cited Count：3 Percentile：71.54(Physics, Multidisciplinary)Hikima, Ryoichi; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*
Heisei-23 Nendo (2011 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.265 - 266, 2011/09
no abstracts in English
Shirasu, Noriko; Kuramoto, Kenichi; Nakano, Yoshihiro; Yamashita, Toshiyuki; Kimura, Yasuhiko; Nihei, Yasuo; Ogawa, Toru
Journal of Nuclear Materials, 376(1), p.88 - 97, 2008/05
Times Cited Count：13 Percentile：64.63(Materials Science, Multidisciplinary)The concept of the rock-like oxide (ROX) fuel has been developed for the annihilation of excess plutonium in light water reactors. Irradiation tests and post-irradiation examinations were carried out on candidate ROX fuels. The ternary fuel of YSZ-spinel-corundum system, the single-phase fuels of YSZ, the particle dispersed fuels of YSZ in spinel or corundum matrix, and the blended fuels of YSZ and spinel or corundum matrix were fabricated and submitted to irradiation tests. The fuels containing spinel showed chemical instabilities with the vaporization of MgO component, which caused fuel restructuring. The swelling behavior was improved with the particle-dispersed fuels. However, the particle-dispersed fuels showed higher fractional gas release (FGR) than blended type fuels. The FGR of YSZ single-phase fuels were comparable to what would be expected for UO fuels. The YSZ single-phase fuel showed the best irradiation performance among the ROX fuels investigated.
Shirasu, Noriko; Kuramoto, Kenichi; Nakano, Yoshihiro; Yamashita, Toshiyuki; Ogawa, Toru
Journal of Power and Energy Systems (Internet), 2(1), p.145 - 152, 2008/00
To evaluate the irradiation behavior of the rock-like oxide fuel, irradiation experiments were carried out. Three fuels were prepared; a single phase fuel of yttria-stabilized zirconia containing UO (U-YSZ) and two types of particle-dispersed fuels of U-YSZ particles in spinel or corundum matrix. These fuels were irradiated in JRR-3 for about 280 days. The burnups were about 11% FIMA. The fission gas release rate (FGR) was determined by puncture test and gas analysis. Corundum-based fuel showed extremely high FGR (88%). The temperature of U-YSZ single-phase fuel pellets was highest among the fuels, because of its low thermal conductivity. Nevertheless the U-YSZ single-phase fuel showed very low FGR (5%). Microstructure analyses of irradiated fuel pellets were carried out by ceramography and EPMA. The restructuring of fuel pellet was not observed in the spinel-based fuel irradiated below 1400 K.
Shirasu, Noriko; Kuramoto, Kenichi; Nakano, Yoshihiro; Yamashita, Toshiyuki; Ogawa, Toru
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 7 Pages, 2007/04
To evaluate the irradiation behavior of the rock-like oxide fuel, irradiation experiments were carried out. Three fuels were prepared; a single phase fuel of yttria-stabilized zirconia containing UO (U-YSZ) and two particle-dispersed fuels of U-YSZ particles in spinel or corundum matrix. These fuels were irradiated in JRR-3 for about 280 days. The burnups were about 11% FIMA. The fission gas release rate (FGR) was determined by puncture test and gas analysis. Corundum-based fuel showed extremely high FGR (88%). On the other hand, the U-YSZ single-phase fuel showed very low FGR (5%). Microstructure analyses for irradiated fuel pellets were carried out by ceramography and EPMA. The restructuring of fuel pellet was not observed in the spinel-based fuel irradiated below 1400 K. Significant appearance changes were not also observed for corundum-based fuel.
Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.
JNC TN9400 2004-035, 2071 Pages, 2004/06
JNC-TN9400-2004-035.pdf:76.42MB
The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.
MO
7(M=Pu, Ce) by EMF methodOtobe, Haruyoshi; Nakamura, Akio; Yamashita, Toshiyuki; Ogawa, Toru
Journal of Nuclear Science and Technology, 39(Suppl.3), p.652 - 655, 2002/11
Pyrochlore-type (P-type) zirconia has been widely studied as a disposable form of the high-level radioactive nuclear waste. We have developed the EMF (electromotive force) measurement system using the cubic zirconia sensor, in order to investigate the oxygen potential (
g(O)) of P-type ZrPu(Ce)O. For P-type ZrCeO at 1078 K, we have found that g(O) vs. oxygen composition (x) relationship has different behavior between x more than 0.34 and x less than 0.34. This may suggest that the degree and way of the ordering of oxide ions (O
) and oxygen vacancies (V0) should change around x =0.34. We have also measured the g(O) vs. temperature (T) relationship between 763 and 1078 K at various x, and derived the partial molar enthalpy (h(O)) and entropy (s(O)) of oxygen. It was found that h(O) and s(O) of P-type ZrCeO exhibit significantly different behavior from those of fluorite-type CeO
. The similar experiments are in progress for P-type ZrPuO, and the results are discussed in comparison with those of P-type ZrCeO mentioned above.
Kato, Takashi; Tsuji, Hiroshi; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Kawano, Katsumi; Oshikiri, Masayuki*; et al.
Fusion Engineering and Design, 56-57, p.59 - 70, 2001/10
Times Cited Count：17 Percentile：74.85(Nuclear Science & Technology)no abstracts in English
Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.
Nuclear Fusion, 41(5), p.645 - 651, 2001/05
Times Cited Count：57 Percentile：83.02(Physics, Fluids & Plasmas)no abstracts in English
Yoshida, Hidetoshi; Naito, Osamu; Yamashita, Osamu; Kitamura, Shigeru; *; *; *; *; Hatae, Takaki; Nagashima, Akira; et al.
Review of Scientific Instruments, 70(1), p.751 - 754, 1999/01
Times Cited Count：15 Percentile：68.26(Instruments & Instrumentation)no abstracts in English
Danhara, Toru*; Yamashita, Toru*
JNC TJ7420 2005-075, 108 Pages, 1997/03
JNC-TJ7420-2005-075.pdf:34.14MB
no abstracts in English
