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Mo
O
( = In, Sc)Iida, Kazuki*; Yoshida, Hiroyuki*; Okabe, Hirotaka*; Katayama, Naoyuki*; Ishii, Yuto*; Koda, Akihiro*; Inamura, Yasuhiro; Murai, Naoki; Ishikado, Motoyuki*; Kadono, Ryosuke*; et al.
Scientific Reports (Internet), 9(1), p.1826_1 - 1826_9, 2019/02
Times Cited Count：13 Percentile：65.14(Multidisciplinary Sciences)Samarakoon, A. M.*; Takahashi, Mitsuru*; Zhang, D.*; Yang, J.*; Katayama, Naoyuki*; Sinclair, R.*; Zhou, H. D.*; Diallo, S. O.*; Ehlers, G.*; Tennant, D. A.*; et al.
Scientific Reports (Internet), 7(1), p.12053_1 - 12053_8, 2017/09
Times Cited Count：10 Percentile：57.09(Multidisciplinary Sciences)Nakatsuji, Satoru*; Kuga, Kentaro*; Kimura, Kenta*; Satake, Ryuta*; Katayama, Naoyuki*; Nishibori, Eiji*; Sawa, Hiroshi*; Ishii, Rieko*; Hagiwara, Masayuki*; Bridges, F.*; et al.
Science, 336(6081), p.559 - 563, 2012/05
Times Cited Count：121 Percentile：95.28(Multidisciplinary Sciences)Frustrated magnetic materials can remain disordered to the lowest temperatures. Such is the case for Ba
CuSb
O
, which is magnetically anisotropic at the atomic scale but curiously isotropic on mesoscopic length and time scales. We find that the frustration on the triangular lattice is imprinted in a nanostructured honeycomb lattice of Cu
ions that resists a coherent static Jahn-Teller distortion. The resulting two-dimensional random-bond spin-1/2 system on the honeycomb lattice has a broad spectrum of spin-dimer like excitations and low-energy spin degrees of freedom that retain.
, CeCd, and PrCd with a caged crystal structureYoshiuchi, Shingo*; Takeuchi, Tetsuya*; Oya, Masahiro*; Katayama, Keisuke*; Matsushita, Masaki*; Yoshitani, Naohisa*; Nishimura, Naoto*; Ota, Hisashi*; Tateiwa, Naoyuki; Yamamoto, Etsuji; et al.
Journal of the Physical Society of Japan, 79(4), p.044601_1 - 044601_11, 2010/04
Times Cited Count：14 Percentile：62.48(Physics, Multidisciplinary)Katayama, Naoyuki*; Uchida, Masaya*; Hashizume, Daisuke*; Niitaka, Seiji*; Matsuno, Jobu*; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Takeshita, Nao*; Gauzzi, A.*; et al.
Physical Review Letters, 103(14), p.146405_1 - 146405_4, 2009/10
Times Cited Count：67 Percentile：89.47(Physics, Multidisciplinary)We investigate LiVS and LiVSe with a triangular lattice as itinerant analogues of LiVO known for the formation of a valence-bond solid (VBS) state out of an S = 1 frustrated magnet. LiVS, which is located at the border between a metal and a correlated insulator, shows a first order transition from a paramagnetic metal to a VBS insulator at T
305 K upon cooling. The presence of a VBS state in the close vicinity of insulator-metal transition may suggest the importance of itinerancy in the formation of a VBS state. We argue that the high temperature metallic phase of LiVS has a pseudogap, likely originating from the VBS fluctuation. LiVSe was found to be a paramagnetic metal down to 2 K.
Takeishi, Toshiharu*; Katayama, Kazunari*; Nishikawa, Masabumi*; Masaki, Kei; Miya, Naoyuki
Journal of Nuclear Materials, 349(3), p.327 - 338, 2006/03
Times Cited Count：6 Percentile：40.51(Materials Science, Multidisciplinary)no abstracts in English
Katayama, Kazunari*; Takeishi, Toshiharu*; Nagase, Hiroyasu*; Manabe, Yusuke*; Nishikawa, Masabumi*; Miya, Naoyuki; Masaki, Kei
Fusion Science and Technology, 48(1), p.561 - 564, 2005/07
Times Cited Count：1 Percentile：10.25(Nuclear Science & Technology)no abstracts in English
Takeishi, Toshiharu*; Katayama, Kazunari*; Nishikawa, Masabumi*; Miya, Naoyuki; Masaki, Kei
Fusion Science and Technology, 48(1), p.565 - 568, 2005/07
Times Cited Count：1 Percentile：10.25(Nuclear Science & Technology)no abstracts in English
Katayama, Kazunari*; Takeishi, Toshiharu*; Manabe, Yusuke*; Nagase, Hiroyasu*; Nishikawa, Masabumi*; Miya, Naoyuki
Journal of Nuclear Materials, 340(1), p.83 - 92, 2005/04
Times Cited Count：8 Percentile：48.32(Materials Science, Multidisciplinary)no abstracts in English
glass under high-pressureMiyauchi, Koichi*; Qiu, J.*; Shojiya, Masanori*; Kawamoto, Yoji*; Kitamura, Naoyuki*; Fukumi, Kohei*; Katayama, Yoshinori; Nishihata, Yasuo
Solid State Communications, 124(5-6), p.189 - 193, 2002/10
Times Cited Count：7 Percentile：38.08(Physics, Condensed Matter)A GeS glass was compressed up to 8 GPa at room temperature, heated up to 270 
C under 8 GPa and then decompressed to ambient pressure at room temperature, using a large volume high-pressure apparatus. The local structural-changes around Ge were examined by means of EXAFS method. The Ge-S bond length became monotonously short with increasing applied-pressure up to 8 GPa at room temperature. When the specimen was heated to 270 C under 8 GPa, however, the vond length became slightly long. The elongated bond lengthe was almost kept even after the temperature was descended to room tempertature. In decompression process, the bond length became gradually long with releasing applied-pressure down to 2 GPa, following a change in compression process. Below 2 GPa, however, the Ge-S bond length was largely elongated, being lnger than the initial one. No significant change of coordination number was found in the compression and decompression processes up to 8 GPa. This change canbe explained by a combined effect of elastic and inelastic structural-changes.
Kato, Takashi*; Takaki, Naoyuki*; Fukaya, Yuji; Ooka, Yasunori*; Katayama, Masaharu*
no journal, ,
Thorium, which is recovered with rare earth mining, is useless, and the utilization should be investigated. In the preset, the thorium utilization as a HTGR fuel had been investigated. The improvement of High Temperature engineering Test Reactor (HTTR) burn-up characteristics by thorium utilization had been investigated by a pin cell model.
Katayama, Masaharu*; Takamatsu, Kuniyoshi; Sawa, Kazuhiro; Takagi, Naoyuki*; Ooka, Yasunori*; Yamasaki, Masatoshi*
no journal, ,
As collaborative research project by Japan Atomic Energy Agency, Toyota Tsusho Corporation and Nuclear Fuel Industries, Ltd., new utilizations of HTGR and new R&D of a cooperative relationship between car industries and HTGR are presented. Specifically, we showed the results of feasibility study on material creation and new-type fuel utilization by using HTTR.
Ooka, Yasunori*; Tanaka, Hideki*; Yamasaki, Masatoshi*; Goto, Minoru; Ueta, Shohei; Takagi, Naoyuki*; Katayama, Masaharu*
no journal, ,
The usage of thorium as nuclear fuel has been focused, which is produced with mining rare metal. The study on thorium fuel utilization is conducted for high temperature gas-cooled reactor (HTGR). We reported about the evaluations on the nuclear characteristics and on manufacturing of the thorium fuel for irradiation test using the High Temperature engineering Test Reactor (HTTR).
Shinohara, Masanori; Shibata, Taiju; Katayama, Masaharu*; Takagi, Naoyuki*; Ooka, Yasunori*; Yamasaki, Masatoshi*
no journal, ,
no abstracts in English
Katayama, Masaharu*; Takamatsu, Kuniyoshi; Sawa, Kazuhiro; Takagi, Naoyuki*; Ooka, Yasunori*; Yamasaki, Masatoshi*
no journal, ,
no abstracts in English
Goto, Minoru; Ueta, Shohei; Katayama, Masaharu*; Takagi, Naoyuki*; Ooka, Yasunori*; Yamasaki, Masatoshi*
no journal, ,
To utilize thorium in a high temperature gas-cooled reactor (HTGR), calculation of its nuclear characteristics with high accuracy is important subject. Criticality, which is one of the important nuclear characteristics, was measured for thorium loaded core by using critical assemblies, and comparisons between the measurements and calculations were reported. While measurement of criticality of thorium loaded core using actual reactor is almost not published. This paper described about measurement of nuclear characteristics of thorium loaded core using a High Temperature Engineering Test Reactor (HTTR).
Ueta, Shohei; Goto, Minoru; Katayama, Masaharu*; Takagi, Naoyuki*; Ooka, Yasunori*; Yamasaki, Masatoshi*
no journal, ,
For the feasibility study on a wide-variety of fuel utilization of the high temperature gas-cooled reactor (HTGR) in order to confirm the integrity and the irradiation performance of thorium as the fuel, the irradiation test with thorium-uranium mixed dioxide fuel (denoted as thorium fuel) by the High temperature engineering test reactor (HTTR) of Japan Atomic Energy Agency (JAEA) has been reviewed, and its neutronic characteristics has been evaluated. With regard to the license, the HTTR and the fuel fabrication plant of Nuclear Fuel Industries, Ltd. have been permitted to treat thorium as the fuel. During the irradiation, the integrity of the fuel specimen can be monitored continuously by the fuel failure detection (FFD) system installed in the HTTR. After the irradiation, the fuel sample is dismantled from the core and post-irradiation examinations are carried out to confirm the integrity and to evaluate the irradiance of the test fuel. The irradiance of the thorium fuel sample have been estimated in case of the irradiation test with three block of the thorium fuel in 4 of thorium to uranium mixed ratio and in 20% of enrichment of uranium-235. As the result, the burnup of the thorium fuel specimens will be approximately 21 GWd/t with 30 MW of reactor power in 660 days of the irradiation duration.
