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1,676 results on '"Kamiyama T"'

151. 50th anniversary and recent decade achievements of the Hokkaido University Neutron Source (HUNS) facility with cold-fast neutrons and high-energy electrons/X-rays

Author

Sato Hirotaka, Kamiyama Takashi, Nagakura Hiroki, Sato Ko-ichi, Ohnuma Masato, and Furusaka Michihiro

Subjects
Physics, QC1-999
Abstract

In this paper, present status, scientific strategy, recent decade achievements and future perspectives of HUNS with cold, thermal, epithermal, fast neutrons and high-energy electrons/X-rays are presented. Time-of-flight small-angle cold neutron scattering with SAXS is useful for extended-duration materials and foods analysis. Irradiations using fast neutrons, thermal neutrons, 32 MeV electrons and MeV-class X-rays are used for not only soft error test of system-level semiconductor devices but also astrophysics and medical biology. Time-of-flight neutron imaging can accept big sample, system-level sample and many samples for crystalline microstructure and temperature analyses in steel, car and cultural heritage research fields. The reasons of such great activities are discussed.

Published
2024
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152. Long Periodic Helimagnetic Ordering in CrM 3S6 (M = Nb and Ta)

Author

Kousaka, Y., Ogura, T., Zhang, J., Miao, P., Lee, S., Torii, S., Kamiyama, T., Campo, J., Inoue, K., and Akimitsu, J.

Subjects
Condensed Matter::Materials Science, Condensed Matter::Strongly Correlated Electrons
Abstract

We report long periodic chiral helimagnetic orderings in ferromagnetic inorganic compounds CrM 3S6 (M = Nb and Ta) with a chiral space group of P6322. Magnetization in polycrystalline samples and high resolution powder neutron diffraction were measured. Our powder neutron diffraction measurements in CrM 3S6 successfully separated nuclear and magnetic satellite peaks, having the period of hundreds of angstroms along the c-axis. Therefore, we propose that the magnetic ordering in ferromagnetic CrM3S6 is not ferromagnetic, but long periodic chiral helimagnetic ordering.

Published
2016

154. Room and low temperature direct three-dimensional-strain measurements by neutron diffraction on as-reacted and prebent CuNb/[Nb.sub.3]Sn wire

Author

Oguro, H., Watanabe, K., Shikanai, F., Kamiyama, T., Katagiri, K., Nishijima, G., Badica, P., and Awaji, S.

Subjects
Copper compounds -- Electric properties, Tin compounds -- Electric properties, Neutrons -- Diffraction, Neutrons -- Analysis, Physics
Abstract

Neutron diffraction is used for measuring the axial and lateral residual strains for the prebent and the as-reacted CuNb[Nb.sub.3]Sn wires at room temperature in order to investigate the change of the residual strain with prebending treatment. The results have indicated that the reduction of the residual strain in the axial direction as well as in the lateral direction is responsible for the enhancement in the superconducting properties of the prebent [Nb.sub.3]Sn wires.

Published
2007

161. Spontaneous structural distortion of the metallic Shastry-Sutherland system DyB4 by quadrupole-spin-lattice coupling

Author

Sim, Hasung, primary, Lee, Seongsu, additional, Hong, Kun-Pyo, additional, Jeong, Jaehong, additional, Zhang, J. R., additional, Kamiyama, T., additional, Adroja, D. T., additional, Murray, C. A., additional, Thompson, S. P., additional, Iga, F., additional, Ji, S., additional, Khomskii, D., additional, and Park, Je-Geun, additional

Published
2016
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162. Charge states of Ca atoms in beta-dicalcium silicate

Author

Mori, K, Kiyanagi, R, Yonemura, M, Iwase, K, Sato, T, Itoh, K, Sugiyama, M, Kamiyama, T, and Fukunaga, T

Subjects
crystal structure, neutron powder diffraction, beta-Ca2SiO4, bond valence sum, Rietveld analysis, radial distribution function, short-range structure
Published
2006

171. Spontaneous structural distortion of the metallic Shastry-Sutherland system DyB4 by quadrupole-spin-lattice coupling

Author

Sim, Hasung, Lee, Seongsu, Hong, Kun-Pyo, Jeong, Jaehong, Zhang, J. R., Kamiyama, T., Adroja, D. T., Murray, C. A., Thompson, S. P., Iga, F., Ji, S., Khomskii, D., Park, Je-Geun, Sim, Hasung, Lee, Seongsu, Hong, Kun-Pyo, Jeong, Jaehong, Zhang, J. R., Kamiyama, T., Adroja, D. T., Murray, C. A., Thompson, S. P., Iga, F., Ji, S., Khomskii, D., and Park, Je-Geun

Abstract

DyB4 has a two-dimensional Shastry-Sutherland (Sh-S) lattice with strong Ising character of the Dy ions. Despite the intrinsic frustrations, it undergoes two successive transitions: a magnetic ordering at T-N = 20K and a quadrupole ordering at T-Q = 12.5K. From high-resolution neutron and synchrotron x-ray powder diffraction studies, we have obtained full structural information on this material in all phases and demonstrate that structural modifications occurring at quadrupolar transition lead to the lifting of frustrations inherent in the Sh-S model. Our paper thus provides a complete experimental picture of how the intrinsic frustration of the Sh-S lattice can be lifted by the coupling to quadrupole moments. We show that two other factors, i.e., strong spin-orbit coupling and long-range Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in metallic DyB4, play an important role in this behavior.

Published
2016

172. Crystal and magnetic structures of Cr1/3NbSe2 from neutron diffraction

Author

Gubkin, A. F., Proskurina, E. P., Kousaka, Y., Sherokalova, E. M., Selezneva, N. V., Miao, P., Lee, S., Zhang, J., Ishikawa, Y., Torii, S., Kamiyama, T., Campo, J., Akimitsu, J., Baranov, N. V., Gubkin, A. F., Proskurina, E. P., Kousaka, Y., Sherokalova, E. M., Selezneva, N. V., Miao, P., Lee, S., Zhang, J., Ishikawa, Y., Torii, S., Kamiyama, T., Campo, J., Akimitsu, J., and Baranov, N. V.

Published
2016

173. Observation of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]-Like Superconducting Gap in an Electron-Doped High-Temperature Superconductor

Author

Sato, T., Kamiyama, T., Takahashi, T., Kurahashi, K., and Yamada, K.

Subjects
Quantum theory -- Research, Superconductivity -- Research, Science and technology, Research
Abstract

High-resolution angle-resolved photoemission spectroscopy of the electrondoped high-temperature superconductor [Nd.sub.2-x][Ce.sub.x]Cu[O.sub.4] (x = 0.15, transition temperature [T.sub.c] = 22 K) has found the quasiparticle signature as well as the anisotropic [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]-like superconducting gap. The spectra[ line shape at the superconducting state shows a strong anisotropic nature of the many-body interaction. The result suggests that the electron-hole symmetry is present in the high-temperature superconductors., The symmetry of the superconducting gap is directly related to the origin of superconductivity (1). For the hole-doped high-temperature superconductors (HTSCs), such as [La.sub.[2-x][Sr.sub.x]Cu[O.sub.4](LSCO), Y[Ba.sub.2][Cu.sub.3][O.sub.7] (YBCO), and [Bi.sub.2][Sr.sub.2]Ca[Cu.sub.2][O.sub.8] (BSCCO), the [...]

Published
2001

182. Colossal negative thermal expansion induced by magnetic phase competition on frustrated lattices in Laves phase compound (Hf,Ta)Fe2

Author

Li, B., primary, Luo, X. H., additional, Wang, H., additional, Ren, W. J., additional, Yano, S., additional, Wang, C.-W., additional, Gardner, J. S., additional, Liss, K.-D., additional, Miao, P., additional, Lee, S.-H., additional, Kamiyama, T., additional, Wu, R. Q., additional, Kawakita, Y., additional, and Zhang, Z. D., additional

Published
2016
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183. Crystal and magnetic structures of Cr1∕3NbSe2 from neutron diffraction

Author

Gubkin, A. F., primary, Proskurina, E. P., additional, Kousaka, Y., additional, Sherokalova, E. M., additional, Selezneva, N. V., additional, Miao, P., additional, Lee, S., additional, Zhang, J., additional, Ishikawa, Y., additional, Torii, S., additional, Kamiyama, T., additional, Campo, J., additional, Akimitsu, J., additional, and Baranov, N. V., additional

Published
2016
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184. Mechanically Induced Carbonization for Formation of Nanocrystalline TiC Alloy

Author

EL-ESKANDARANY, M. Sherif, OMORI, M., KAMIYAMA, T., KONNO, T. J., SUMIYAMA, K., HIRAI, T., and SUZUKI, K.

Subjects
morphology, nanocrystalline materials, structure, titanium carbide, consolidation, mechanical alloying
Abstract

A single phase of NaCl-type structure of Ti_C_ alloy powder has been synthesized by ball-milling elemental Ti and graphite powders at room temperature. The end-product of Ti_C_ that is obtained after 720 ks of milling consists of fine grains of about 3 nm in diameter and possesses homogeneous powder with an average particle diameter of less than 0.4μm. The milled powder has been consolidated into bulk samples, using a plasma activated sintering method. This consolidation step leads to the formation of fully-dense TiC compacts with nano-structure grains. The as-milled powder and the as-consolidated bulk samples have been characterized after selected milling times by means of X-ray diffraction, transmission electron microscope, scanning electron microscope and chemical analyses. Some of the compacted samples were investigated by small-angle X-ray scattering and high-resolution transmission electron microscope. The hardness and some mechanical properties of the end-product are reported. On the basis of the results of the present study, the ball-milling technique accompanied with plasma activated sintering can provide powerful tools for fabrication of nanocrystalline TiC bulk alloys.

Published
1997

187. Feeding of the tintinnid ciliate Favella taraikaensis on the toxic dinoflagellate Alexandrium tamarense and the fate of prey toxins

Author

Kamiyama, T, Suzuki, T, and Okumura, Y

Subjects
accumulation, Alexandrium tamarense, ciliate, grazing, PSP
Abstract

To establish the fate of paralytic shellfish poisoning (PSP) toxins in planktonic foodwebs, feeding activities of the planktonic ciliate Favella taraikaensis on the PSP-producing alga Alexandrium tamarense were examined in laboratory experiments and the toxin content in the ciliates was quantified by fluorometric high-performance liquid chromatography. In six experiments,F. taraikaensis actively fed on A. tamarense and grew rapidly. The maximum specific growth and ingestion rates of F. taraikaensis on a diet of A. tamarense (>300 cells ml–1) ranged from 0.7 day–1 to 1.5 day–1 and from3.1 cells individual–1 h–1 to 5.8 cells individual–1 h–1 respectively. The PSP toxin content in F. taraikaensis grown on A. tamarense was low and the individual toxin content of F. taraikaensis was lower than the cellular toxin content of A. tamarense. The PSP toxins of A. tamarense were therefore scarcely accumulated within F. taraikaensis during the feeding process.

Published
2011

190. Energy resolution of pulsed neutron beam provided by the ANNRI beamline at the J-PARC/MLF

Author

Kino, K., Furusaka, M., Hiraga, F., Kamiyama, T., Kiyanagi, Y., Furutaka, K., Goko, S., Hara, K. Y., Harada, H., Harada, M., Hirose, K., Kai, T., Kimura, A., Kin, T., Kitatani, F., Koizumi, M., Maekawa, F., Meigo, S., Nakamura, S., Ooi, M., Ohta, M., Oshima, M., Toh, Y., Igashira, M., Katabuchi, T., Mizumoto, M., Hori, J., Kino, K., Furusaka, M., Hiraga, F., Kamiyama, T., Kiyanagi, Y., Furutaka, K., Goko, S., Hara, K. Y., Harada, H., Harada, M., Hirose, K., Kai, T., Kimura, A., Kin, T., Kitatani, F., Koizumi, M., Maekawa, F., Meigo, S., Nakamura, S., Ooi, M., Ohta, M., Oshima, M., Toh, Y., Igashira, M., Katabuchi, T., Mizumoto, M., and Hori, J.

Abstract

We studied the energy resolution of the pulsed neutron beam of the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) at the Japan Proton Accelerator Research Complex/Materials and Life Science Experimental Facility (J-PARC/MLF). A simulation in the energy region from 0.7 meV to 1 MeV was performed and measurements were made at thermal (0.76-62 meV) and epithermal energies (4.8-410 eV). The neutron energy resolution of ANNRI determined by the time technique depends on the Lime structure of the neutron pulse. We obtained the neutron energy resolution as a function of the neutron energy by the simulation in the two operation modes of the neutron source: double- and single bunch modes in double bunch mode, the resolution deteriorates above about 10 eV because the time structure of the neutron pulse splits into two peaks. The time structures at 13 energy points from measurements in the thermal energy region agree with those of the simulation. In the epithermal energy region, the time structures at 17 energy points were obtained from measurements and agree with those of the simulation. The FWHM values of the time structures by the simulation and measurements were found to be almost consistent. In the single-bunch mode, the energy resolution is better than about 1% between 1 meV and 10 keV at a neutron source operation of 17.5 kW. These results confirm the energy resolution of the pulsed neutron beam produced by the ANNRI beamline. (C) 2013 Elsevier B.V. All rights reserved.

Published
2014

193. Magnetic properties of Ce3PbC

Author

Kosaka, M., Koiwai, S., Uwatoko, Y., Môri, N., Onodera, H., Ohoyama, K., Abe, H., Kitazawa, H., Kido, G., Kamiyama, T., Noda, H., and Omura, T.

Published
2002
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194. INELASTIC NEUTRON SCATTERING STUDY OF HOST AND GUEST MOLECULAR MOTIONS IN METHANE HYDRATE

Author

Kamiyama, T., Seki, N., Iwasa, H., Uchida, T., Kiyanagi, Y., Ebinuma, Takao, Narita, Hideo, Igawa, N., Ishii, Y., and Bennington, S.M.

Subjects
Astrophysics::Earth and Planetary Astrophysics, Physics::Chemical Physics
Abstract

Methane hydrate has a unique structure that the host water framework forms two kinds of cages, which contain one methane molecule each. Therefore, it has been expected that there may exist three kinds of translational modes of a methane molecule and also the distortion of translational mode of host water molecules compared with normal ice. We need information of the host and guest molecular dynamics over the wide momentum and energy transfer region for studying such dynamics. In this study inelastic neutron measurements were carried under 40 K with MARI spectrometer at ISIS in UK, TAS at JRR-3 and CAT at KENS in Japan. For the methane molecular motion we could confirm its freelike rotation by complementary use of MARI and TAS spectra. After the subtraction of the scattering intensity of the rotation evaluated by the free rotation model from the experimental data, three kinds of translation modes were identified at first experimentally. On the experimental spectra there still remains the excess intensity which could not explain the single mode excitation. The libration mode of the water framework shows the different momentum and energy transfer dependence with those of normal ice. The feature of the libration mode is resemble to ice-IX, that could be considered as a proton ordering of the cage structure appeared in ice-II, VIII and IX.

Published
2008
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200. Inducion of Operational Tolerance By a Cell Therapy Using Donor Ag-Pulsed Tregs in Living Donor Liver Transplantation.

Author

Yamashita, K., primary, Goto, R., additional, Zaitsu, M., additional, Nagatsu, A., additional, Oura, T., additional, Watanabe, M., additional, Aoyagi, T., additional, Suzuki, T., additional, Shimamura, T., additional, Kamiyama, T., additional, Sato, N., additional, Sugita, J., additional, Hatanaka, K., additional, Demetris, A., additional, Bashuda, H., additional, Okumura, K., additional, and Todo, S., additional

Published
2014
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