Fujii, Yutaka*; Takada, Chie
FBNews, (540), p.7 - 11, 2021/12
no abstracts in English
Nakano, Masanao; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Okura, Takehisa; Kuramochi, Akihiko; Kawasaki, Masatsugu; Takeuchi, Erina; Fujii, Yutaka*; Jinno, Tsukasa*; et al.
Hoken Butsuri (Internet), 55(2), p.102 - 109, 2020/06
After the Fukushima-Daiichi Nuclear Power Station (1F) Accident in March 2011, the increase was significantly observed in a part of the result of the environmental radiation monitoring in Ibaraki prefecture. "The review meeting of the environmental effect from 1F accident" was established to discuss technically the fluctuation of monitoring data. The review meeting collected the monitoring data from the four nuclear operators, and discussed a fluctuating trend, Cs/Cs activity ratio, and so on. In this report, the results of the dose rate and Cs in fallout, surface soil, flatfish and seabed sediment are introduced. Also the problem solving in the review meeting is introduced.
Sato, Yutaka*; Kokawa, Hiroyuki*; Fujii, Hiromichi*; Yano, Yasuhide; Sekio, Yoshihiro
Metallurgical and Materials Transactions A, 46(12), p.5789 - 5800, 2015/12
Dissimilar friction stir welding (FSW) of an 11% Cr ferritic/martensitic stee (PNC-FMS) to 316-grade austenitic stainless steel was attempted with a view to its potential application to the wrapper tubes of next-generation fast reactors. The mechanical properties and microstructure of the resulting welds were systematically examined, which revealed that FSW produces a defect-free stir zone in which material intermixing is notably absent. That is, both steels are separately distributed along a zigzagging interface in the stir zone when PNC-FMS is placed on the retreating side, with the tool plunging at the butt line. This interface did not act as a fracture site during small-sized tensile testing of the stir zone. Furthermore, the microstructure of the stir zone was refined in both the PNC-FMS and 316 stainless steel sides, resulting in improved mechanical properties over the respective base material regions.
Nakamura, Hideo; Arai, Kenji*; Oikawa, Hirohide*; Fujii, Tadashi*; Umezawa, Shigemitsu*; Abe, Yutaka*; Sugimoto, Jun*; Koshizuka, Seiichi*; Yamaguchi, Akira*
Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.5353 - 5366, 2015/08
Yamaki, Tatsunori*; Abe, Yutaka*; Kaneko, Akiko*; Segawa, Tomomi; Kawaguchi, Koichi; Yamada, Yoshikazu; Fujii, Kanichi*
Journal of Nuclear Science and Technology, 52(2), p.241 - 250, 2015/02
In the Microwave Heating de-nitration method developed in Japan, a mixed solution of uranyl nitrate and plutonium nitrate recovered from the spent fuel in the reprocessing plant is converted directly to mixed oxide (MH-MOX) powder. This MH-MOX powder is utilized to fabricate MOX fuel with UO powder for FBR. The MH method is accompanied with transient boiling phenomena such as overflow and flushing. Toward high-speed and high-capacity conversion by MH-method in the future, it is required to avoid overflow and flushing and to understand optimal design conditions for design and operation. At the first step for these objectives, basic knowledge of transient boiling phenomena by the MH-method has been acquired with using distilled water. It was observed that generation of singular bubble triggered flushing and distilled water just before flushing was superheated by a temperature 10 degrees centigrade higher than boiling temperature. Based on these results, it is clarified that the occurrence criteria of flushing correlate with absorbed power in the water and released power from the water surface.
Owada, Kenji; Yamauchi, Toru*; Fujii, Yasuhiko*; Ueda, Yutaka*
Physical Review B, 85(13), p.134102_1 - 134102_4, 2012/04
We have investigated the critical phenomena of the metal-to-insulator (MI) transition of -NaVO. The critical exponent of 0.226(3) and anisotropic diffuse scattering suggest that the MI transition of -NaVO is two-dimensional in nature and that the dimension of the order parameter is not Ising. The non-Ising-like order parameter indicates that the MI transition is not a simple order-disorder type such as that of '-NaVO but charge-density-wave-like, where the valence at each V site is continuous and the arrangement is modulated. This closely corresponds to the situation predicted by neutron diffraction measurements and NMR measurements.
Sanada, Hiroyuki; Sugita, Yutaka; Fujii, Yoshiaki*
Proceedings of 3rd International Workshop and Conference on Earth Resources Technology 2009 (CD-ROM), p.149 - 158, 2009/05
EDZ is considered to be important issues in repositories since this is relevant to plug design, support design etc. As a part of the research and development on the geological isolation, JAEA has been implementing the Horonobe URL Project. Deformation and failure behavior around a shaft in URL is described in the paper. Tunnel shape are being measured by a laser displacement sensor to clarify dimension and mechanism of breakouts along the shaft wall. Displacement measurement by extensometers are being carried out to understand deformation behavior in the surrounding rock mass. Breakouts of about 50 cm deep in N-S direction are more frequently observed with excavation depth. The breakout direction was consistent with the maximum horizontal stress which was estimated to be approximately in E-W direction by hydrofracturing tests. Compressive deformation of rock mass also increased with excavation depth. Most part of the deformation occurred within 1 m from the shaft wall.
Matsukawa, Makoto; Kikuchi, Mitsuru; Fujii, Tsuneyuki; Fujita, Takaaki; Hayashi, Takao; Higashijima, Satoru; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Ide, Shunsuke; Ishida, Shinichi; et al.
Fusion Engineering and Design, 83(7-9), p.795 - 803, 2008/12
no abstracts in English
Kimura, Akihiko*; Nagai, Yasuyoshi*; Fujii, Katsuhiko*; Nishiyama, Yutaka; Soneda, Naoki*
Nihon Genshiryoku Gakkai-Shi ATOMO, 50(10), p.630 - 633, 2008/10
no abstracts in English
Miyazawa, Yutaka*; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Morohashi, Keita*; Kakizaki, Takehiko*; et al.
Journal of Radiation Research, 49(4), p.373 - 379, 2008/07
We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporary suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed expression of gene, but not gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi*; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.
Hoshako, 21(2), p.87 - 96, 2008/03
Devil's flower has been found in a temperature-pressure phase diagram of NaVO, which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an X-ray structural analysis and a resonant X-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaVO. The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that it is the first time that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between a Ising spins may result from the Ising spin-phonon coupling.
Miyazawa, Yutaka*; Sakashita, Tetsuya; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Morohashi, Keita*; Kakizaki, Takehiko*; Funayama, Tomoo; Hamada, Nobuyuki*; et al.
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 116, 2008/03
We examined the role of root cap and elongation zone cells in root hydrotropism of using heavy ion and laser microbeam. Heavy ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy ion broad beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
Hoshino, Katsumichi; Suzuki, Takahiro; Isayama, Akihiko; Ide, Shunsuke; Takenaga, Hidenobu; Kubo, Hirotaka; Fujita, Takaaki; Kamada, Yutaka; Fujii, Tsuneyuki; Tsuda, Takashi; et al.
Fusion Science and Technology, 53(1), p.114 - 129, 2008/01
We report on the applications of the ECH to the JT-60U tokamak. The ECH contributes to the advanced tokamak study in JT-60U in such respects as (1)NTM suppression, (2)Study on the internal transport barrier, (3)Impurity exhaust, (4)Tokamak start-up without center solenoid, (5)Current hole study, (6)Confinement and transport study, and (7)Start-up and shut-down assist. These contributions comes from the good local coupling of the ECH to the tokamak plasma.
Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.
Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01
Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.
Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.
Physical Review B, 76(9), p.094113_1 - 094113_10, 2007/09
Structural relations between two ground states of the ANNNI (Axial Next Nearest Neighbor Ising) compound NaVO, C- and C-phases below and above the transition pressure = 1 GPa, were investigated by X-ray diffraction and scattering techniques. The structure of the C-phase is well explained by the () pattern which is one of four layers () of the C-phase, however, the amount of the atomic shifts under the conditions 1.6 GPa and 6 K is 27% that under ambient pressure. On the other hand, resonant X-ray scattering showed that the charges are disproportionated under high pressure. Based on these facts, it was concluded that charge disproportionation corresponds to the Ising variable in NaVO, where the atomic shifts are regarded as linearly coupled to the Ising spins. These results lead to the hypothesis that the competitive interactions between the Ising spins may result from the Ising spin-phonon coupling.
Kikuchi, Hikomitsu*; Chiba, Meiro*; Fujii, Yutaka*; Yamamoto, Yuji*; Higemoto, Wataru; Nishiyama, Kusuo*
Journal of Magnetism and Magnetic Materials, 310(2, Part2), p.e400 - e402, 2007/03
H NMR and SR measurements on Ni(333-tet) (-N) (ClO), a gapless S=1 Heisenberg antiferromagnet with bond alternation, are measured. The spin lattice relaxation rate has anomaly at around 3 K without divergent behavior. The time spectra of SR are measured down to 1.7 K. A fast relaxation component develops below about 3 K, suggesting an occurrence of magnetic ordering. However, the ordering is found to have dynamical nature, since recovery of the asymmetry by applying longitudinal field was not observed.
Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.
Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03
no abstracts in English
Miyazawa, Yutaka*; Negishi, Hiroshi*; Sakashita, Tetsuya; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Funayama, Tomoo; Wada, Seiichi*; Hamada, Nobuyuki*; Kakizaki, Takehiko; et al.
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 119, 2007/02
Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.
Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12
To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.
Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.
Nuclear Fusion, 46(3), p.S29 - S38, 2006/03
The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.