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Suzuki, Tatsuya*; Nomura, Masao*; Fujii, Yasuhiko*; Ikeda, Atsushi; Takaoka, Toru*; Oguma, Koichi*
Nihon Ion Kokan Gakkai-Shi, 21(3), p.328 - 333, 2010/09
Zinc isotope fractionation in an anion exchange resin has been investigated in hydrochloric acid solution by chromatographic technique. It was found that the heavier zinc isotopes were located disproportionately in the solution phase. The isotope fractionation coefficient was varied from the order of 10
to 10
depending on the hydrochloric acid concentration. The maximum isotope fractionation coefficient was obtained in 1 
hydrochloric acid, while the distribution coefficient of zinc became maximum at around 2 hydrochloric acid. This difference has been further discussed based on the calculated speciation and structural information derived from X-ray absorption spectroscopy.
Sasaki, Yuji; Kimura, Takaumi; Oguma, Koichi*
Nihon Ion Kokan Gakkai-Shi, 18(4), p.354 - 359, 2007/10
Many diamide-type extractants were synthesized and tested for the extraction of actinides (III), (IV), (V) and (VI). The diglycolamides (DGA) with two amidic oxygen and one ether oxygen, which show the tridentate feature, have the high extractability of actinides (An). In order to increase the lipophilic property, the diglycolamides with the different functional groups attached to N atoms were synthesized and examined for their extractability. It was found that tetraoctyl-diglycolamide (TODGA) and tetradecyl-diglycolamide (TDDGA) exhibit the satisfactory dissolution into dodecane with less solubility in H
O. The results of various metal extractions using TODGA revealed that the divalent, trivalent and tetravalent metals with ionic radius of 90-120 pm gave notably high D values. After elucidation of the effect on substitution of the functional group, the chemical form of DGA to have high performance on An extraction was proposed.
Fujinami, Masanori*; Oguma, Koichi*; Akahane, Takashi*; Kawasuso, Atsuo; Maekawa, Masaki
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 151, 2007/02
no abstracts in English
Fujinami, Masanori*; Watanabe, Kazuya*; Oguma, Koichi*; Akahane, Takashi*; Kawasuso, Atsuo; Maekawa, Masaki; Matsukawa, Kazuto*; Harada, Hirofumi*
no journal, ,
no abstracts in English
Akahane, Takashi*; Fujinami, Masanori*; Watanabe, Kazuya*; Oguma, Koichi*; Matsukawa, Kazuto*; Harada, Hirofumi*; Maekawa, Masaki; Kawasuso, Atsuo
no journal, ,
no abstracts in English
Sasaki, Yuji; Kimura, Takaumi; Oguma, Koichi*
no journal, ,
no abstracts in English
Sasaki, Yuji; Kimura, Takaumi; Oguma, Koichi*
no journal, ,
no abstracts in English
Fujinami, Masanori*; Watanabe, Kazuya*; Oguma, Koichi*; Akahane, Takashi*; Kawasuso, Atsuo; Maekawa, Masaki; Matsukawa, Kazuto*
no journal, ,
no abstracts in English
Kawasuso, Atsuo; Maekawa, Masaki; Fujinami, Masanori*; Oguma, Koichi*; Akahane, Takashi*; Watanabe, Kazuya*; Matsukawa, Kazuto*
no journal, ,
Transition-metals are ubiquitous in Si devices to degrade their properties. Gettering has proved effective to trap contaminants and it is important to study their interaction. Extended defects such as stacking faults and precipitates have been investigated by TEM and impurity profile is analyzed by SIMS. However, such a approach cannot afford us the interaction of them. PAS is a powerful tool to analyze the defects and their coupled elements. A Cz-Si wafer was implanted with 3MeV Si ions to dose of 1E+14/cm
and Cu ion implantation was done into the back side (200 keV, 1E+14/cm). Variable-energy positron beam was employed and coincidence Doppler broadening spectra were taken at 15 keV after sample annealing. Up to 500
C, no differences between with and without Cu ion implantation are found and the clustering of vacancies takes place. At 600C, the profile is very similar to that for the bulk Cu. At 700C, the trapped Cu are released and oxygen atoms are coupled with vacancy clusters.
Sasaki, Yuji; Kitatsuji, Yoshihiro; Kimura, Takaumi; Oguma, Koichi*
no journal, ,
no abstracts in English
Sasaki, Yuji; Kimura, Takaumi; Oguma, Koichi*
no journal, ,
no abstracts in English
