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Journal Articles

Retreat from stress; Rattling in a planar coordination

Suekuni, Koichiro*; Lee, C. H.*; Tanaka, Hiromi*; Nishibori, Eiji*; Nakamura, Atsushi*; Kasai, Hidetaka*; Mori, Hitoshi*; Usui, Hidetomo*; Ochi, Masayuki*; Hasegawa, Takumi*; et al.

Advanced Materials, 30(13), p.1706230_1 - 1706230_6, 2018/03

 Times Cited Count:39 Percentile:89.79(Chemistry, Multidisciplinary)

Thermoelectric materials for highly efficient devices must satisfy conflicting requirements of high electrical conductivity and low thermal conductivity. In this paper, we studied the crystal structure and phonon dynamics of tetrahedrites (Cu,Zn)$$_{12}$$(Sb,As)$$_{4}$$S$$_{13}$$. The results revealed that the Cu atoms in a planar coordination are rattling, which effectively scatter phonons. These findings provide a new strategy for the development of highly efficient thermoelectric materials with planar coordination.

Journal Articles

REDOX state analysis of platinoid elements in simulated high-level radioactive waste glass by synchrotron radiation based EXAFS

Okamoto, Yoshihiro; Shiwaku, Hideaki; Nakada, Masami; Komamine, Satoshi*; Ochi, Eiji*; Akabori, Mitsuo

Journal of Nuclear Materials, 471, p.110 - 115, 2016/02

 Times Cited Count:5 Percentile:49.98(Materials Science, Multidisciplinary)

Extended X-ray Absorption Fine Structure (EXAFS) analyses were performed to evaluate REDOX (REDuction and OXidation) state of platinoid elements in simulated high-level nuclear waste glass samples prepared under different conditions of temperature and atmosphere. At first, EXAFS functions were compared with those of standard materials such as RuO$$_2$$. Then structural parameters were obtained from a curve fitting analysis. In addition, a fitting analysis used a linear combination of the two standard EXAFS functions of a given elements metal and oxide was applied to determine ratio of metal/oxide in the simulated glass. The redox state of Ru was successfully evaluated from the linear combination fitting results of EXAFS functions. The ratio of metal increased at more reducing atmosphere and at higher temperatures. Chemical form of rhodium oxide in the simulated glass samples was RhO$$_2$$ unlike expected Rh$$_2$$O$$_3$$. It can be estimated rhodium behaves according with ruthenium when the chemical form is oxide.

Journal Articles

High-speed classification of coherent X-ray diffraction Patterns on the K computer for high-resolution single biomolecule imaging

Tokuhisa, Atsushi*; Arai, Junya*; Jochi, Yasumasa*; Ono, Yoshiyuki*; Kameyama, Toyohisa*; Yamamoto, Keiji*; Hatanaka, Masayuki*; Gerofi, B.*; Shimada, Akio*; Kurokawa, Motoyoshi*; et al.

Journal of Synchrotron Radiation, 20(6), p.899 - 904, 2013/11

 Times Cited Count:5 Percentile:26.18(Instruments & Instrumentation)

Journal Articles

High-temperature X-ray imaging study of simulated high-level waste glass melt

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 81(7), p.543 - 546, 2013/07

 Times Cited Count:5 Percentile:14.09(Electrochemistry)

The molten state of simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. X-ray intensity was obtained easily by digitizing gray-scale values in the image. The existence of ruthenium element is emphasized as a black color in the CCD image at X-ray energy higher than the Ru K-absorption edge. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was also performed to clarify the chemical state of ruthenium element in the melt.

Journal Articles

High-temperature X-ray imaging study of simulated high-level waste glass melt

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Proceedings of 4th Asian Conference on Molten Salt Chemistry and Technology & 44th Symposium on Molten Salt Chemistry, Japan, p.47 - 52, 2012/09

The molten state of the simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. The existence of ruthenium in the X-ray CCD image was emphasized over the energy of Ru K-absorption edge. X-ray intensity was obtained easily by digitalizing gray-scale values in the image. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was performed to clarify the chemical state of ruthenium element in the melt.

Journal Articles

Synchrotron radiation-based X-ray imaging study of ruthenium in simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Shiwaku, Hideaki; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(2), p.127 - 132, 2012/06

Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. At first, we measured a test sample containing RuO$$_2$$ and Ru metal powder. We successfully obtained information on the Ru distribution in the sample. In addition, the chemical state (oxide or metal ?) of each small Ru-rich spot was evaluated by the corresponding position sensitive XAFS spectrum. The imaging XAFS technique was applied to some simulated high-level waste glass samples. The Ru distribution of the glass sample and their chemical state were confirmed by image analyses. It can be seen that Ru element scattered in the glass sample exists as oxide RuO$$_2$$.

Journal Articles

Controls over structural and electronic properties of epitaxial graphene on silicon using surface termination of 3C-SiC(111)/Si

Fukidome, Hirokazu*; Abe, Shunsuke*; Takahashi, Ryota*; Imaizumi, Kei*; Inomata, Shuya*; Handa, Hiroyuki*; Saito, Eiji*; Enta, Yoshiharu*; Yoshigoe, Akitaka; Teraoka, Yuden; et al.

Applied Physics Express, 4(11), p.115104_1 - 115104_3, 2011/11

 Times Cited Count:34 Percentile:79.73(Physics, Applied)

Journal Articles

Evaluation of HLW glass dissolution/alteration kinetics by using micro-channel flow-through test method; Initial glass dissolution rate as a function of pH and temperature

Inagaki, Yaohiro*; Sakatani, Keiichi*; Yamamura, Yuki*; Mitsui, Seiichiro; Noshita, Kenji*; Miura, Yoshiyuki*; Kanehira, Norio*; Ochi, Eiji*; Mukunoki, Atsushi*; Chiba, Tamotsu*

Dai-7-Kai Saishori, Risaikuru Bukai Semina Tekisuto, p.136 - 137, 2011/01

Conventional static test methods are not appropriate to evaluate glass dissolution behavior at an arbitrarily-fixed condition due to compositional change of the solution with glass dissolution. In this study, we applied a newly-devised micro-channel flow-through test method to measurement of the initial dissolution rates of Japanese simulated waste glasses, JAEA-P0798 and JNFL-KMOC, at arbitrarily-fixed conditions and we evaluated temperature and pH dependence of glass dissolution. The results showed that the initial dissolution rate increased with temperature and had "V-shaped" pH dependence at each temperature.

Journal Articles

Progress of the ITER central solenoid model coil programme

Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.

Nuclear Fusion, 41(5), p.645 - 651, 2001/05

 Times Cited Count:55 Percentile:83.89(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

None

*; *; Ochi, Eiji*

PNC TJ4125 86-002, 107 Pages, 1986/11

PNC-TJ4125-86-002.pdf:10.81MB

None

Oral presentation

Synchrotron radiation based X-ray imaging study of simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Minato, Kazuo; Shiwaku, Hideaki; Yaita, Tsuyoshi; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; et al.

no journal, , 

Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. It can be seen that Ru element scattered in the glass sample exists as oxide RuO$$_2$$.

Oral presentation

Properties of insoluble residue generated at Rokkasho Reprocessing Plant, 5; Oxidation behavior of insoluble residue

Takano, Masahide; Yamagishi, Isao; Akabori, Mitsuo; Minato, Kazuo; Yoshioka, Masahiro*; Ochi, Eiji*; Fukui, Toshiki*; Komamine, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

Properties of insoluble residue generated at Rokkasho Reprocessing Plant, 1; Introduction

Minato, Kazuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Yoshioka, Masahiro*

no journal, , 

Characteristics of the fine produced during the reprocessing of the spent fuel in the Rokkasho Reprocessing Plant are inevitable data to understand the behavior of the fine in the glass melter. It is also necessary to obtain the characteristic data of the fine to judge the validity of vitrification tests with simulated fine in KMOC facility. The property measurements and chemical reaction tests with simulated fine are valuable to obtain fundamental data that is necessary for the development of a new type of glass melter. With these objectives, the fine was transported from the Rokkasho Reprocessing Plant to the Tokai Research Center of the Japan Atomic Energy Agency and the fine and simulated fine were characterized.

Oral presentation

Study on Noble Metals sedimentation and viscosity of molten glass

Miyauchi, Atsushi; Nakajima, Masayoshi; Morikawa, Yo; Masaki, Toshio; Kobayashi, Hidekazu; Yamashita, Teruo; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English

Oral presentation

Properties of insoluble residue generated at Rokkasho Reprocessing Plant, 4; EPMA analysis of real and simulated insoluble residue

Akabori, Mitsuo; Takano, Masahide; Yamagishi, Isao; Minato, Kazuo; Yoshioka, Masahiro*; Ochi, Eiji*; Fukui, Toshiki*; Komamine, Satoshi*

no journal, , 

Properties of real insoluble residues generated at Rokkasho Reprocessing Plant were measured by using SEM/EPMA. The simulated insoluble residues were prepared by conventional powder metallurgy technique, and properties such as particle size were compared with those of real ones.

Oral presentation

Influence of long-term melting on the noble metals shape and glass viscosity

Morikawa, Yo; Miyauchi, Atsushi; Nakajima, Masayoshi; Masaki, Toshio; Kobayashi, Hidekazu; Yamashita, Teruo; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English

Oral presentation

Synchrotron radiation based imaging XAFS analysis of simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

no journal, , 

Distribution and the chemical state of fission product elements like Zr, Mo and Ru in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. We used the high resolution imaging system and the high-speed CCD camera for imaging XAFS measurement of the glass sample at molten state. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the CCD camera.

Oral presentation

Properties and behavior of insoluble residue in the cold cap, 2; High temperature chemical form of simulated residue coexisting with nitrates

Takano, Masahide; Yamagishi, Isao; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*

no journal, , 

no abstracts in English

Oral presentation

Study on the noble metals sedimentation behavior in the melted glass

Morikawa, Yo; Miyauchi, Atsushi; Nakajima, Masayoshi; Oyama, Koichi; Yamashita, Teruo; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English

Oral presentation

Properties and behavior of insoluble residue in the cold cap, 1; Outline and reaction behavior in the cold cap

Akabori, Mitsuo; Yamagishi, Isao; Takano, Masahide; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*

no journal, , 

no abstracts in English

36 (Records 1-20 displayed on this page)