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Journal Articles

Coexistence of ferromagnetic and stripe-type antiferromagnetic spin fluctuations in YFe$$_{2}$$Ge$$_{2}$$

Wo, H.*; Wang, Q.*; Shen, Y.*; Zhang, X.*; Hao, Y.*; Feng, Y.*; Shen, S.*; He, Z.*; Pan, B.*; Wang, W.*; et al.

Physical Review Letters, 122(21), p.217003_1 - 217003_5, 2019/05

 Times Cited Count:5 Percentile:42.69(Physics, Multidisciplinary)

Journal Articles

Spontaneous decays of magneto-elastic excitations in non-collinear antiferromagnet (Y,Lu)MnO$$_{3}$$

Oh, J.*; Le, M. D.*; Nahm, H.-H.*; Sim, H.*; Jeong, J.*; Perring, T. G.*; Woo, H.*; Nakajima, Kenji; Kawamura, Seiko; Yamani, Z.*; et al.

Nature Communications (Internet), 7, p.13146_1 - 13146_6, 2016/10

 Times Cited Count:56 Percentile:86.85(Multidisciplinary Sciences)

Magnons and phonons are fundamental quasiparticles in a solid and can be coupled together to form a hybrid quasi-particle. However, detailed experimental studies on the underlying Hamiltonian of this particle are rare for actual materials. Moreover, the anharmonicity of such magnetoelastic excitations remains largely unexplored, although it is essential for a proper understanding of their diverse thermodynamic behaviour and intrinsic zero-temperature decay. Here we show that in non-collinear antiferromagnets, a strong magnon phonon coupling can significantly enhance the anharmonicity, resulting in the creation of magnetoelastic excitations and their spontaneous decay. By measuring the spin waves over the full Brillouin zone and carrying out anharmonic spin wave calculations using a Hamiltonian with an explicit magnon phonon coupling, we have identified a hybrid magnetoelastic mode in (Y,Lu)MnO$$_{3}$$ and quantified its decay rate and the exchange-striction coupling termrequired to produce it.

Journal Articles

Properties of tritium/helium release from hot isostatic pressed beryllium of various trademarks

Chekushina, L.*; Dyussambayev, D.*; Shaimerdenov, A.*; Tsuchiya, Kunihiko; Takeuchi, Tomoaki; Kawamura, Hiroshi; Kulsartov, T.*

Journal of Nuclear Materials, 452(1-3), p.41 - 45, 2014/09

 Times Cited Count:6 Percentile:26.79(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Managing beryllium in nuclear facility applications

Longhurst, G. R.*; Tsuchiya, Kunihiko; Dorn, C.*; Folkman, S. L.*; Fronk, T. H.*; Ishihara, Masahiro; Kawamura, Hiroshi; Tranter, T. N.*; Rohe, R.*; Uchida, Munenori*; et al.

Nuclear Technology, 176(3), p.430 - 441, 2011/12

 Times Cited Count:12 Percentile:66.82(Nuclear Science & Technology)

Beryllium has important roles in nuclear facilities such as fission reactors and fusion reactors. Its neutron multiplication capability and low atomic weight make it very useful as a reflector in fission reactors. In both applications, the beryllium and the impurities in it become activated by neutrons transmutating to radionuclides, some of which are long-lived and difficult to dispose of. Also, gas production, notably helium and tritium, results in swelling, embrittlement, and cracking, which means that the beryllium must be replaced periodically, especially in fission reactors where dimensional tolerances must be maintained. It has long been known that neutron activation of inherent iron and cobalt in the beryllium results in significant $$^{60}$$Co activity. In 2001, it was discovered that activation of naturally occurring contaminants in the beryllium creates sufficient $$^{14}$$C and $$^{94}$$Nb to render the irradiated beryllium "Greater-Than-Class-C" for disposal in US radioactive waste facilities. In this paper we review the extent of the disposal issue, processes that have been investigated or considered for improving the disposability of irradiated beryllium, and approaches for recycling.

Journal Articles

Study of tritium and helium release from irradiated lithium ceramics Li$$_{2}$$TiO$$_{3}$$

Kulsartov, T.*; Tazhibayeva, I.*; Gordienko, Y.*; Chikhray, E.*; Tsuchiya, Kunihiko; Kawamura, Hiroshi; Kulsartova, A.*

Fusion Science and Technology, 60(3), p.1139 - 1142, 2011/10

 Times Cited Count:13 Percentile:69.64(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Tritium accumulation and release from Li$$_{2}$$TiO$$_{3}$$ during long-term irradiation in the WWR-K reactor

Tazhibayeva, I.*; Beckman, I.*; Shestakov, V.*; Kulsartov, T.*; Chikhray, E.*; Kenzhin, E.*; Kuykabaeva, A.*; Kawamura, Hiroshi; Tsuchiya, Kunihiko

Journal of Nuclear Materials, 417(1-3), p.748 - 752, 2011/10

 Times Cited Count:16 Percentile:75.8(Materials Science, Multidisciplinary)

For the first time the data was obtained on tritium release from $$^{6}$$Li-enriched (96%) lithium metatitanate under high lithium burn-up (up to 23%). Proposed mathematics and software of the reactor experiments allowed to interpret the experimental results of tritium release study. Tritium was continuously generated as a result of the nuclear reaction of lithium-6 and thermal neutrons under variable thermal impacts (graduated heating and cooling) on lithium metatitanate Li$$_{2}$$TiO$$_{3}$$. Main gas release parameters were calculated in order to assess acceptability of the use of lithium metatitanate granules in tritium breeders; the parameters are as follows: gas release rate, tritium retention in the materials, retention time, activation energy of thermal desorption HT, activation energy of volume diffusion T$$^{+}$$, as well as corresponding pre-exponential (frequency) indexes. It was discovered that the tritium release process is mainly controlled by tritium volume diffusion, however, capture of tritium by the point defects and tritium molization at the material's surface played the certain role in the process as well. It was discovered that as lithium is burnt-up, the activation energy of tritium release decreases and tends to a constant value under high lithium-6 burn-up.

Journal Articles

Study of Li$$_{2}$$TiO$$_{3}$$ + 5 mol% TiO$$_{2}$$ lithium ceramics after long-term neutron irradiation

Chikhray, Y.*; Shestakov, V.*; Maksimkin, O.*; Turubarova, L.*; Osipov, I.*; Kulsartov, T.*; Kuykabayeba, A.*; Tazhibayeva, I.*; Kawamura, Hiroshi; Tsuchiya, Kunihiko

Journal of Nuclear Materials, 386?388, p.286 - 289, 2009/04

 Times Cited Count:19 Percentile:76.21(Materials Science, Multidisciplinary)

The PIE (Post Irradiation Examinations) results of Li$$_{2}$$TiO$$_{3}$$ pebbles added with 5 mol% TiO$$_{2}$$ after the long-term irradiation tests are described in this paper. 96 at% $$^{6}$$Li-enriched Li$$_{2}$$TiO$$_{3}$$ pebbles were prepared as the irradiation specimens and these specimens were irradiated during 223 days at the reactor power of 6 MWt in the WWR-K of NNC-RK. After neutron irradiation, light-colored pebbles became gray-colored due to structure changes which generation of gray-colored inclusions with low density and microhardness. Crystal structure of the pebbles after the irradiation test were changed from the results of X-ray diffraction measurement. The value of maximum permissible load (pebble crash limit) at that was also low. The residual tritium in the pebbles was measured after the irradiation test.

Journal Articles

The H-Invitational Database (H-InvDB); A Comprehensive annotation resource for human genes and transcripts

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.

Journal Articles

Tritium generation in lithium ceramics Li$$_{2}$$TiO$$_{3}$$ for fusion reactor blanket

Tazhibayeva, I. L.*; Kenzhin, E. A.*; Kulsartov, T. V.*; Kuykabayeva, A. A.*; Shestakov, V.*; Chikhray, E.*; Gizatulin, S.*; Maksimkin, O. P.*; Beckman, I. N.*; Kawamura, Hiroshi; et al.

Questions of Atomic Science and Technology, 2, p.3 - 11, 2008/00

Lithium titanate (Li$$_{2}$$TiO$$_{3}$$) was chosen as a tentative reference material from viewpoints of good tritium recovery at low temperatures and of low tritium inventory and chemical stability for the breeding blanket in fusion reactors. The results of the irradiation tests of Li$$_{2}$$TiO$$_{3}$$ in the WWR-K of NNC-RK are described in this paper. 96at% $$^{6}$$Li-enriched Li$$_{2}$$TiO$$_{3}$$ pebbles and disks were prepared as the irradiation specimens and these specimens were irradiated during 220 days (5350 hours) at the reactor power of 6 MWt. Tritium release was measured continuously during irradiation tests and tritium release properties were evaluated. The mechanics describing generation and release of tritium from the irradiated Li$$_{2}$$TiO$$_{3}$$ were analyzed. There was estimated tritium loss due to recoil energy and binding of tritium in HTO, and there was calculated stationary tritium release due to diffusion under constant temperature and under thermal cycling.

Journal Articles

Structure, composition and properties of lithium ceramic Li$$_{2}$$TiO$$_{3}$$+5% mole TiO$$_{2}$$ irradiated in WWR-K reactor for solid ceramic blanket of fusion reactor

Tazhibayeva, I. L.*; Kulsartov, T.*; Kenzhin, E. A.*; Maksimkin, O. P.*; Doronina, T. A.*; Silnyagina, N. S.*; Turubarova, L. G.*; Tsai, K. V.*; Zheltov, D. A.*; Kashirskiy, V. V.*; et al.

Questions of Atomic Science and Technology; Series the Thermonuclear Fusion, 1, p.3 - 11, 2008/00

The paper contains and analyzes the results of integrated material studies of lithium ceramic Li$$_{2}$$TiO$$_{3}$$ + 5% mole TiO$$_{2}$$ irradiated in reactor WWR-K during 5,350 hours under controlled conditions taking into account effects of tritium generated in the course of irradiation. The changes in density, microstructure, phase and chemical composition, strength and microhardness were studies; lithium burn-up level and tritium residual content were defined. The significant influence of radiation-thermal impacts on structure and properties of ceramic samples were observed. It was shown that irradiation resulted in lithium ceramics softening, at that this effect depended on irradiation temperature. It was discovered the radiation change of phase composition of lithium ceramic.

Journal Articles

Use of WWR-K reactor for long-term trials of lithium ceramic Li$$_{2}$$TiO$$_{3}$$ for fusion reactor blanket

Tazhibayeva, I. L.*; Kenzhin, E. A.*; Chachrov, P. V.*; Arinkin, F. M.*; Gasatulin, Sh. Kh.*; Bekamukhabetov, E. S.*; Shestakov, V. P.*; Chikhray, E. V.*; Kulsartov, T. V.*; Kuykabaeva, A. A.*; et al.

Questions of Atomic Science and Technology; Series the Thermonuclear Fusion, 2, p.3 - 10, 2007/00

no abstracts in English

Journal Articles

Anthropogenic radionuclides in sediment in the Japan Sea; Distribution and transport processes of particulate radionuclides

Otosaka, Shigeyoshi; Amano, Hikaru; Ito, Toshimichi; Kawamura, Hideyuki; Kobayashi, Takuya; Suzuki, Takashi; Togawa, Orihiko; Chaykovskaya, E. L.*; Lishavskaya, T. S.*; Novichkov, V. P.*; et al.

Journal of Environmental Radioactivity, 91(3), p.128 - 145, 2006/00

 Times Cited Count:20 Percentile:42.21(Environmental Sciences)

Distributions of radionuclides ($$^{90}$$Sr, $$^{137}$$Cs and $$^{239+240}$$Pu) in seabed sediment in the Japan Sea were observed during 1998-2002. Observed inventories of anthropogenic radionuclides in sediment ranged 0.1-86 Bq m$$^{-2}$$ for $$^{90}$$Sr, 23-379 Bq m$$^{-2}$$ for $$^{137}$$Cs and 0.1-86 Bq m$$^{-2}$$ for $$^{239+240}$$Pu. In the deep part ($$>$$ 2 km depth) of the western Japan Basin, $$^{239+240}$$Pu/$$^{137}$$Cs inventory ratios were larger than those in the central Yamato Basin although inventories of radionuclides were not different between basins. The higher $$^{239+240}$$Pu/$$^{137}$$Cs ratios in the western Japan Basin were derived by the production of Pu-enriched particle in the surface layer and effective sinking of particulate materials in this region. In the marginal Yamato Basin and the Ulleung Basin, both inventories and $$^{239+240}$$Pu/$$^{137}$$Cs ratios in sediment were larger than those in the central Yamato Basin. In the eastern/southern Japan Sea, it was suggested that the supply of particulate radionuclides by the TWC enhanced accumulation of radionuclides in this region.

Journal Articles

Anthropogenic radionuclides in seawater of the Japan Sea; The Results of recent observations and the temporal change of concentrations

Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Kawamura, Hideyuki; Amano, Hikaru; Senju, Tomoharu*; Chaykovskaya, E. L.*; et al.

Journal of Nuclear Science and Technology, 42(1), p.90 - 100, 2005/01

 Times Cited Count:14 Percentile:67.84(Nuclear Science & Technology)

During 1996-2002, a wide-area research project on anthropogenic radionuclides was done in the Japanese and Russian EEZ of the Japan Sea to investigate their migration. As the results of expeditions in 2001 and 2002, (1) the concentrations and distributions of radionuclides are similar to the results of previous, (2) inventories of these radionuclides indicate accumulation in the Japan Sea seawater compared to the amounts supplied by global fallout, (3) $$^{90}$$Sr and $$^{137}$$Cs concentrations in intermediate layer show temporal variations, and 4) the variations may reflect the water mass movement in upper part of the Japan Sea.

Journal Articles

Soft X-ray reflectivity and structure evaluation of CoCr/C multilayer X-ray mirrors for spectral region around 6nm

Takenaka, Hisataka*; Nagai, Komei*; Ito, Hisashi*; Muramatsu, Yasuji; Kawamura, T.*; Gullikson, E. M.*; Perera, R. C. C.*

Nuclear Instruments and Methods in Physics Research A, 467-468(Part1), p.337 - 340, 2001/07

 Times Cited Count:8 Percentile:52.36(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Electrochemical properties of hydrogen concentration cell with ceramic protonic conductor

Kakuta, Toshiya*; Konishi, Satoshi; Kawamura, Yoshinori; Nishi, Masataka; Suzuki, T.*

Fusion Technology, 39(2-Part2), p.1083 - 1087, 2001/03

no abstracts in English

Journal Articles

Improvement of tritium accountancy technology for the ITER fuel cycle safety enchancement

Ohira, Shigeru; Hayashi, Takumi; Nakamura, Hirofumi; Kobayashi, Kazuhiro; Tadokoro, Takahiro*; Nakamura, H.*; Ito, Takeshi*; Yamanishi, Toshihiko; Kawamura, Yoshinori; Iwai, Yasunori; et al.

Nuclear Fusion, 40(3Y), p.519 - 525, 2000/03

 Times Cited Count:24 Percentile:59.01(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Development of a tritium fuel processing systems using an electrolytic reactor for ITER

Yamanishi, Toshihiko; Kawamura, Yoshinori; Iwai, Yasunori; Arita, Tadaaki*; Maruyama, T.*; Kakuta, Toshiya*; Konishi, Satoshi; Enoeda, Mikio; Ohira, Shigeru; Hayashi, Takumi; et al.

Nuclear Fusion, 40(3Y), p.515 - 518, 2000/03

 Times Cited Count:6 Percentile:21.01(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Demonstration of the integrated fusion fuel loop at the tritium process laboratory of the Japan Atomic Energy Research Institute

Yamanishi, Toshihiko; Konishi, Satoshi; Hayashi, Takumi; Kawamura, Yoshinori; Iwai, Yasunori; Maruyama, T.*; Kakuta, Toshiya*; Ohira, Shigeru; Nakamura, Hirofumi; Kobayashi, Kazuhiro; et al.

Fusion Technology, 34(3), p.536 - 540, 1998/11

no abstracts in English

Journal Articles

Improvement of tritium accountancy technology for the ITER fuel cycle safety enhancement

Ohira, Shigeru; Hayashi, Takumi; Nakamura, Hirofumi; Kobayashi, Kazuhiro; Tadokoro, Takahiro*; Nakamura, H.*; Ito, Takeshi*; Yamanishi, Toshihiko; Kawamura, Yoshinori; Iwai, Yasunori; et al.

Fusion Energy 1998, 3, p.1069 - 1072, 1998/10

no abstracts in English

Journal Articles

Effect of MgO and BaO on Fe$$^{3+}$$/Fe$$^{2+}$$ equilibrium in a candidate glass for immobilization of high level nuclear waste

Ohashi, S.*; Okumura, T.*; Kawamura, Kazuhiro; Miyamoto, Yoichi; Iwase, Masanori*

High Temperature Materials and Processes, 16(3), p.169 - 172, 1997/00

None

24 (Records 1-20 displayed on this page)