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Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：6 Percentile：84.97(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Watanabe, Jin*; Araki, Yasufumi; Kobayashi, Koji*; Ozawa, Akihiro*; Nomura, Kentaro*
Journal of the Physical Society of Japan, 91(8), p.083702_1 - 083702_5, 2022/08
Times Cited Count：3 Percentile：58.88(Physics, Multidisciplinary)We investigate magnetic orderings on kagome lattice numerically from the tight-binding Hamiltonian of electrons, governed by the filling factor and spin-orbit coupling (SOC) of electrons. We find that even a simple kagome lattice model can host both ferromagnetic and noncollinear antiferromagnetic orderings depending on the electron filling, reflecting gap structures in the Dirac and flat bands characteristic to the kagome lattice. Kane-Mele- or Rashba-type SOC tends to stabilize noncollinear orderings, such a magnetic spirals and 120-degree antiferromagnetic orderings, due to the effective Dzyaloshinskii-Moriya interaction from SOC. The obtained phase structure helps qualitative understanding of magnetic orderings in various kagome-layered materials with Weyl or Dirac electrons.
Araki, Yasufumi; Watanabe, Jin*; Nomura, Kentaro*
Journal of the Physical Society of Japan, 90(9), p.094702_1 - 094702_9, 2021/09
Times Cited Count：1 Percentile：16.57(Physics, Multidisciplinary)While nodal-line semimetals with magnetism have been theoretically predicted and experimentally observed in a few compounds, idea on the relation between the magnetic order and the electronic structure is still limited. We theoretically explore the electronic structure in bulk and boundary of such a magnetic nodal-line state by introducing magnetism in topological Dirac semimetal (TDSM). TDSMs, such as 
and 
,are characterized by a pair of spin-degenerate Dirac points protected by rotational symmetries of crystals. By introducing local magnetic moments coupled to the electron spins in the lattice model of TDSM, we show that the TDSM can turn into either a Weyl semimetal or a nodal-line semimetal, which is determined by the orbital dependence in the exchange coupling and the direction of magnetization formed by the magnetic moments. In this magnetic nodal-line semimetal state, we find zero modes with drumhead-like band structure at the boundary that are characterized by the topological number of 
. Those zero modes are numerically demonstrated by introducing magnetic domain walls in the lattice model.
Kurebayashi, Daichi*; Araki, Yasufumi; Nomura, Kentaro*
Journal of the Physical Society of Japan, 90(8), p.084702_1 - 084702_9, 2021/08
Times Cited Count：8 Percentile：61.42(Physics, Multidisciplinary)We theoretically study current- and charge-induced spin torque in magnetic Weyl semimetals. In magnetic Weyl semimetals (WSM), topologically nontrivial band structure mediates anomalous coupling between magnetization and transport, making WSMs preferable for spintronics systems. In this paper, we determine all current-induced spin torques including spin-orbit torque and spin-transfer torque, up to first order with respect to spatial and temporal derivatives and electrical currents. We also calculate the charge-induced spin torque microscopically. We find the charge-induced spin torque originates from the chiral anomaly due to the correspondence between spin operators and axial current operators in our model.
Araki, Yasufumi; Misawa, Takahiro*; Nomura, Kentaro*
Physical Review Research (Internet), 3(2), p.023219_1 - 023219_15, 2021/06
We theoretically propose the long-range spin transport mediated by the gapless surface states of topological Dirac semimetal (TDSM). Low-dissipation spin current is a building block of next-generation spintronics devices. While conduction electrons in metals and spin waves in ferromagnetic insulators (FMIs) are the major carriers of spin current, their propagation length is inevitably limited due to the Joule heating or the Gilbert damping. In order to suppress dissipation and realize long-range spin transport, we here make use of the spin-helical surface states of TDSMs, such as Cd
As
and NaBi, which are robust against disorder. Based on a junction of two FMIs connected by a TDSM, we demonstrate that the magnetization dynamics in one FMI induces a spin current on the TDSM surface flowing to the other FMI. By both the analytical transport theory on the surface and the numerical simulation of real-time evolution in the bulk, we find that the induced spin current takes a universal semi-quantized value that is insensitive to the microscopic coupling structure between the FMI and the TDSM. We show that this surface spin current is robust against disorder over a long range, which indicates that the TDSM surface serves as a promising system for realizing spintronics devices.
Araki, Yasufumi; Misawa, Takahiro*; Nomura, Kentaro*
Physical Review Research (Internet), 2(2), p.023195_1 - 023195_11, 2020/05
Nomura, Katsuhiro; Tanikawa, Shinichi*; Amamiya, Hiroki; Yasue, Kenichi
JAEA-Data/Code 2016-015, 49 Pages, 2017/03
JAEA-Data-Code-2016-015.pdf:2.88MB
The uplift of the last hundred thousand years in the Japanese Islands has been acquired mainly using marine and river terraces. We arranged information regarding the uplift in a table. This data is one of the useful information for the development of the investigation technology of uplift and for the research of the landform evolution in Japanese islands.
Shiomi, Yuki*; Nomura, Kentaro*; Kajiwara, Yosuke*; Eto, Kazuma*; Novak, M.*; Segawa, Koji*; Ando, Yoichi*; Saito, Eiji
Physical Review Letters, 113(19), p.196601_1 - 196601_5, 2014/11
Times Cited Count：272 Percentile：99.03(Physics, Multidisciplinary)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
Times Cited Count：51 Percentile：71.25(Biochemistry & Molecular Biology)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.
Hasegawa, Katsushi; Nomura, Masahiro; Schnase, A.; Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito*; Omori, Chihiro*; Hara, Keigo*; Toda, Makoto*; Takagi, Akira*; et al.
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.457 - 459, 2006/00
no abstracts in English
Tomiyasu, Hiroshi*; Nomura, Mitsuo; Yamazaki, Hitoshi; Hayashibara, Kenichi
JNC TY6400 2004-004, 18 Pages, 2004/07
JNC-TY6400-2004-004.pdf:0.65MB
This study has been performed to establish a method to recover uranium from uranium containing NaF and CaF2 wastes without forming any secondary wastes. For this purpose the use of supercritical carbon dioxide was primarily considered. Although TBP has been generally used with supercritical carbon dioxide to extract uranium, the use of TBP was ruled out in the present study because of the formation of secondary wastes due to phosphorous oxides. Among a variety of ligands, we have choused acetylacetone as a ligand for the extraction of uranyl ion. Acetylacetone is a strong chelate ligand, which dose not gives any solid residual after vaporization. As a matter of fact, our experimental result indicates that acetylacetone is a stronger ligand for uranyl ion compared with TBP., because uranyl TBP complex is replaced by acetylacetonate resulting in the formation of acetylaetonate complex. Experiments were carried out to recover uranium from the NaF waste by use of supercritical carbon dioxide containing acetylacetone, and it was found that uranium was only partly extracted to carbon dioxide phase. This might be attributed to the strong uranium fluoride complexes and also to the distribution of uranium to the inside of NaF pellets. In order to recover uranium from the NaF waste, another method was also carried out as follows: dissolve NaF waste by hot water, then add NaOH to the solution as to form the precipitation of uranium hydrolyzed species, where uranium can be recovered at high yield using centrifugation, and finally the addition of ethanol yields the NaF powder. In conclusion, the recovery of uranium from fluoride wastes seems to be difficult by the method using supercritical carbon dioxide; however, we have established a new method to recover both uranium and NaF in high yield.
Aihara, Masahiko*; Yanai, Shinjiro*; Shimazaki, Yohei*; Nomura, Mitsuo; Yamazaki, Hitoshi; Hayashibara, Kenichi
JNC TY6400 2004-003, 93 Pages, 2004/07
JNC-TY6400-2004-003.pdf:2.19MB
To run the nuclear fuel cycle safely, new treatment and disposal technologies of radioactive waste from the cycle must be developed. Super critical CO2 extraction attracts attention as a technology to recover the uranium in low level solid waste. In this paper it is proposed that use of carbonation of calcium oxide and decarbonation of calcium carbonate for the system which recovers and reuses high pressure carbon dioxide discharge form the super-critical process. Conducting the cycle reaction experiment at the high pressure of carbon dioxide with the calcium oxide absorbent, the reaction velocity analysis, the structural analysis of solid reactant, the numerical analysis of the reaction characteristic and the recover-reuse process were discussed. The rate of carbonation at about 2MPa was most rapid with the stable reaction conversion of about 0.4 through 5 cycles. In the range of these experiment conditions The solid reactant was observed consisting of about 1-10 mm particles of the aggregate of minute grains. It was found that a blockade of the void between the grains after carbonation at high pressure CO2 caused the reduction of conversion and rate of carbonation. The heat consumption of CO2 recovery for the recover-reuse system was estimated by use of the reaction analysis data.
Tsuzuki, Kazuhiro; Kimura, Haruyuki; Kawashima, Hisato; Sato, Masayasu; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Hoshino, Katsumichi; Bakhtiari, M.; Kasai, Satoshi; et al.
Nuclear Fusion, 43(10), p.1288 - 1293, 2003/10
Times Cited Count：39 Percentile：74.23(Physics, Fluids & Plasmas)no abstracts in English
to obtain the high U solution; *; Sakurai, Koji*; ; Nomura, Kazunori; *
JNC TN8400 2000-032, 98 Pages, 2000/12
JNC-TN8400-2000-032.pdf:1.94MB
Concerning the preparation of high U solution for the crystallization process and the application of UO powder dissolution to that, the effects of final U concentration, dissolution temperature, nitric acid concentration and powder size on the dissolution of UO powder in the nitric acid where the final U concentration was 
800g/L were investigated. The experimental results showed that the solubility of UO decreased with the increase of final UO concentration and powder size, and with the decrease of dissolution temperature and nitric acid concentration. It was also confirmed that in the condition where the final U concentration was sufficiently lower than the solubility of U, UO dissolution behavior in the high U solution could be estimated with the equation based on the fragmentation model which we had already reported. Based on these experimental results, the dissolution behavior of irradiated MOX fuel in high U solution was estimated and the possibility of supplying high U solution to the crystallization process was discussed. In the preparation of high U solution for the crystallization process, it was estimated that the present dissolution process (dissolution for fuel pieces of about 3cm long) needed a lot of time to obtain a high dissolution yield, but it was shorted drastically by the pulverization of fuel pieces. The burst of off-gas at the early in the dissolution of fuel powder seems to be avoidable with setting the appropriate dissolution condition, and it is important to optimize the dissolution condition with considering the capacity of off-gas treatment process.
Sugikawa, Susumu; ; ; Nakazaki, Masato; Shirahashi, Koichi; ; *; *; Tsuji, Kenichi*; Tachimori, Shoichi; et al.
JAERI-Tech 97-007, 86 Pages, 1997/03
no abstracts in English
Nishina, Kojiro*; *; Miyoshi, Yoshinori; Suzaki, Takenori; Okuno, Hiroshi; Nomura, Yasushi; Mitake, Susumu*; ; Tonoike, Kotaro; *; et al.
Nihon Genshiryoku Gakkai-Shi, 38(4), p.262 - 271, 1996/00
no abstracts in English
Okuno, Hiroshi; Komuro, Yuichi; Nakajima, Ken; Nomura, Yasushi; Naito, Yoshitaka; Nishina, Kojiro*; *; *; Miyoshi, Yoshinori; *; et al.
JAERI-Tech 95-048, 168 Pages, 1995/10
no abstracts in English
Okuno, Hiroshi; Komuro, Yuichi; Nakajima, Ken; Nomura, Yasushi; Naito, Yoshitaka
ICNC 95: 5th Int. Conf. on Nuclear Criticality Safety, Vol. I, 0, p.2.61 - 2.65, 1995/00
no abstracts in English
Asaka, Takeo; ; ; ; Shibahara, Itaru; Shikakura, Sakae
Journal of Nuclear Materials, 204, p.102 - 108, 1993/00
Times Cited Count：4 Percentile：44.87(Materials Science, Multidisciplinary)None
Nomura, Masahiro; Toyama, Shinichi; *; ;
PNC TN9410 92-213, 27 Pages, 1992/08
We are developing a test CW electron linac to develop a high power accelerator. In the key technology development, activity is focused on the developments of electron gun, klystron, and accelerator tube for high power RF. It is very important for a high power accelerator to develop an electron gun, because the beam current depends on electron gun. This paper presents the present status. We introduce in this paper the cathode material, the emission type, the accelerating field, and preliminary results of electron trajectories calculated by EGUN code.
