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and NpO in highly concentrated chloride solutionsFujii, Toshiyuki*; Uehara, Akihiro*; Kitatsuji, Yoshihiro; Yamana, Hajimu*
Journal of Radioanalytical and Nuclear Chemistry, 303(1), p.1015 - 1020, 2015/01
Times Cited Count：6 Percentile：45.92(Chemistry, Analytical)The 
symmetric vibrational frequency of UO in chloride solutions was studied by Raman spectrometry and ab initio calculations. The frequency experimentally obtained decreased with the increase of concentration of Cl in solvent chlorides. This is attributable to that hydration water molecules in the equatorial plane of UO are substituted by Cl
ions, which was consistent with the calculation results. The theoretical part was expanded to aqua- and chloro- Np(VI) complexes. The frequencies of neptunyl species computed were acceptable compared with the reported Raman shifts.
-Ca interaction in highly concentrated calcium chlorideFujii, Toshiyuki*; Uehara, Akihiro*; Kitatsuji, Yoshihiro; Yamana, Hajimu*
Journal of Radioanalytical and Nuclear Chemistry, 301(1), p.293 - 296, 2014/07
Times Cited Count：6 Percentile：42.97(Chemistry, Analytical)Coordination circumstance of neptunyl ion in concentrated CaCl solutions was analyzed by Raman spectrometry. Besides the symmetric stretch () mode of NpO and NpO, the asymmetric stretch (
) mode of NpO was found. The Raman intensity of the mode increased with the concentration of CaCl in the system. This would be attributable to the cation-cation interaction between Np(V) and Ca(II).
- and 
-TbAlB
at low temperature and high magnetic fieldsMatsuda, Yasuhiro*; Nakamura, Toshiyuki*; Kuga, Kentaro*; Nakatsuji, Satoru*; Michimura, Shinji*; Inami, Toshiya; Kawamura, Naomi*; Mizumaki, Masaichiro*
Journal of the Korean Physical Society, 62(12), p.1778 - 1781, 2013/06
Times Cited Count：10 Percentile：55.98(Physics, Multidisciplinary)The valence state of Yb ions in - and -YbAlB has been investigated by X-ray absorption and emission spectroscopy at temperatures from 2 to 280 K. It is found that the valence gradually increases with increasing temperature toward 3+ and that the characteristic temperature of the valence fluctuations is about 290 K. We also observe a small increase in the Yb valence (
0.002) in -YbAlB by a magnetic field of 32 T at 40 K.
Tagami, Masahiko*; Yamada, Yasuhiro*; Yamashita, Yoshihiko*; Miyakawa, Ayumu*; Matsuoka, Toshifumi*; Xue, Z.*; Tsuji, Takeshi*; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Amano, Kenji; et al.
JAEA-Research 2012-036, 110 Pages, 2013/02
JAEA-Research-2012-036.pdf:44.93MB
Northeast strike faults developed in and around the Mizunami Underground Research Laboratory (MIU) control groundwater flow. These faults were possibly formed as a part of pull-apart structure by the right lateral movement of the Tsukiyoshi fault distributed in the north of MIU site. But the formational mechanism of these faults is still uncertain. In this joint research, the analog experiment and the numerical simulation were used to restore the geological structures around MIU site. The paleo-stress analysis were exposed an ancient deformation mechanism, and the formation timing was presumed in the regional tectonics. The results are adopted for the design of the analog experiment and the numerical simulation. The results of obtained analog experiment and numerical simulation are verified three-dimensionally, and then compared to the current geological structure model. Then the geological structure in the uninvestigated area is estimated.
Tachi, Yukio; Nakazawa, Toshiyuki*; Ochs, M.*; Yotsuji, Kenji; Suyama, Tadahiro; Seida, Yoshimi; Yamada, Norikazu*; Yui, Mikazu
Radiochimica Acta, 98(9-11), p.711 - 718, 2010/11
Times Cited Count：25 Percentile：84.21(Chemistry, Inorganic & Nuclear)Diffusion and sorption of radionuclides in compacted bentonite are the key processes in the safe geological disposal. The effects of carbonate and salinity on Np(V) diffusion and sorption in compacted montmorillonite were investigated by experimental and modeling approaches. Effective diffusion coefficients (
) and distribution coefficients (
) of Np in montmorillonite compacted to dry density of 800 kg/m
were measured under four conditions with different salinities (0.05/0.5 M NaCl) and carbonate concentrations (0/0.01 M NaHCO). The for carbonate-free conditions decreased as salinity increased, and those for carbonate conditions showed the opposite dependency. The decreased by one order of magnitude under high carbonate condition. Diffusion and sorption behaviors were interpreted by coupling the thermodynamic aqueous speciation, the thermodynamic sorption model based on ion exchange and surface complexation, and the diffusion model based on electrical double layer theory in narrow pores. The mechanistic model could be useful in predicting the sorption and diffusion behavior of complex species in compacted systems.
Yamashita, Toshiyuki; ; Tsuji, Toshihide*; *
Journal of Alloys and Compounds, 271-273, p.404 - 407, 1998/00
Times Cited Count：9 Percentile：55.08(Chemistry, Physical)no abstracts in English
Yamashita, Toshiyuki; *; Tsuji, Toshihide*; Kato, Tetsuya*; *; Iwashita, Mitsushige*
Journal of Alloys and Compounds, 271-273, p.400 - 403, 1998/00
Times Cited Count：4 Percentile：39.22(Chemistry, Physical)no abstracts in English
and some other actinide dioxidesYamashita, Toshiyuki; Shirasu, Noriko; Tsuji, Toshihide*; *
Journal of Nuclear Materials, 245(1), p.72 - 78, 1997/00
Times Cited Count：104 Percentile：98.55(Materials Science, Multidisciplinary)no abstracts in English
Yamashita, Toshiyuki; Shirasu, Noriko; Tsuji, Toshihide*; Kato, Tetsuya*
Journal of Nuclear Materials, 247, p.90 - 93, 1997/00
Times Cited Count：51 Percentile：94.73(Materials Science, Multidisciplinary)no abstracts in English
Yamashita, Toshiyuki; ; Ouchi, Kinji; Muromura, Tadasumi; Tsuji, Toshihide*; *; Kato, Tetsuya*
Journal of Alloys and Compounds, 213-214, p.375 - 377, 1994/00
Times Cited Count：12 Percentile：66.82(Chemistry, Physical)no abstracts in English
Tsuji, Toshihide*; *; Yamashita, Toshiyuki; Fujino, Takeo*
Journal of Alloys and Compounds, 213-214, p.378 - 380, 1994/00
Times Cited Count：1 Percentile：25.3(Chemistry, Physical)no abstracts in English
at low oxygen partial pressuresFujino, Takeo*; Yamashita, Toshiyuki; Ouchi, Kinji; *; Tsuji, Toshihide*
Journal of Nuclear Materials, 202, p.154 - 162, 1993/00
Times Cited Count：11 Percentile：72.08(Materials Science, Multidisciplinary)no abstracts in English
Tsuji, Shunji; Neyatani, Yuzuru; Hosogane, Nobuyuki; Matsukawa, Makoto; ; Totsuka, Toshiyuki; Kimura, Toyoaki
JAERI-M 91-196, 36 Pages, 1991/11
no abstracts in English
Tsuji, Toshiyuki*; Kobayashi, Akira*; Yoshida, Eiji*; Ichihara, Chikara*; Adachi, Shigeto*; Ishii, Yasuyuki; Haga, Junji
no journal, ,
no abstracts in English
Tachi, Yukio; Yotsuji, Kenji; Suyama, Tadahiro; Nakazawa, Toshiyuki*; Shimoda, Satoko*; Kuno, Yoshio*
no journal, ,
Sorption and diffusion of radionuclides in compacted bentonite are key processes in the safe geological disposal. The effects of porewater pH and salinity on Ni sorption and diffusion in compacted montmorillonite were investigated by experimental and modeling approaches. Distribution coefficients (Kd) and effective diffusion coefficients (De) of Ni in montmorillonite compacted to dry density of 800 kg/m were measured under four conditions with different pH (6, 8) and salinities (0.05, 0.5 M NaCl). The Kd increased with increasing pH and with decreasing salinity of porewater, which are consistent with batch-derived Kd trends. The De values changed with porewater salinity, which are independent of pH. Sorption and diffusion behaviors were interpreted by coupling the thermodynamic sorption model, and the diffusion model based on EDL theory in narrow pores. The mechanistic model could be useful in predicting the sorption and diffusion of high sorbing species in compacted systems.
Tachi, Yukio; Shimoda, Satoko*; Nakazawa, Toshiyuki*; Suyama, Tadahiro*; Yotsuji, Kenji
no journal, ,
Sorption and diffusion behaviors of Ni in compacted montmorillonite were investigated under different pH and salinity conditions by batch sorption and diffusion experiments. The Ni sorption was measured under four conditions with different pH (6, 8) and salinities (0.05, 0.5 M NaCl), and as functions of Ni concentration and reaction time. The tracer-depletion curves and depth profiles obtained for compacted montmorillonite with dry density of 800 kg/m were interpreted by first-order kinetics sorption based on batch sorption results. The Kd increased with increasing pH and with decreasing salinity of porewater, which are consistent between batch and diffusion tests. Sorption and diffusion behaviors were interpreted by coupling the thermodynamic sorption model, and the diffusion model based on EDL theory in narrow pores.
