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Niihara, Takafumi*; Yokoyama, Tatsunori; Arai, Tomoko*; Misawa, Keiji*
Meteoritics & Planetary Science, 56(8), p.1619 - 1625, 2021/08
Times Cited Count:1 Percentile:10.87(Geochemistry & Geophysics)We have conducted petrological and mineralogical studies on an igneous clast in the Northwest Africa (NWA) 1685 (LL4) chondrite. In an earlier description, the meteorite contained similar clasts in the LL chondritic breccias Yamato (Y)-74442 (LL4), Bhola (LL3-6), and Kraehenberg (LL5). We carefully compared their textures as well as mineral and matrix compositions with those of alkali-rich clasts in the LL chondritic breccias. Olivine grains are embedded in glassy matrix and have no chemical. Shock melt veins and fractures were observed only in olivine grains and did not continue to matrix. Major and minor element compositions of olivine grains in the clast are homogeneous. Potassium abundance of matrix glasses of the NWA 1685 clast is lower than those of alkali-rich igneous clasts in Y-74442, Bhola, and Kraehenberg, indicating that the igneous clasts in NWA 1685 are different from the alkali-rich clasts previously reported in the LL chondritic breccias and that they could have formed during an impact melting event, quenched on the LL-chondrite parent body, and finally incorporated into breccia.
Matsumura, Tatsuro; Takeshita, Kenji*
ACS Symposium Series, 933, p.261 - 273, 2006/07
Three TPEN isomers with different positon of nitrogen donor in pyridyl groups, t2pen, t3pen and t4pen, were synthesized and the extraction separation of Am(III) and Eu(III) with these ligands and a fatty acid, decanoic acid, was investigated. All isomers were similar in the complexation in the aqueous phase, such as the protonation and the formation of metal complex, however, they showed different extraction behavior of Am and Eu. The synergistic extraction effect for Am was observed for t2pen and the high separation factor about 100 was measured, when 1:2. The value is comparable to that for the extraction system with a famous nitrogen-donor extractant, BTP. On the other hand, the extractability of other isomers was very low and no separation of Am and Eu was observed. Only t2pen, in which nitrogen donor in pyridyl groups is positioned in the vicinity of the skeletal structure (N-C-C-N structure) of ligand, is available for the extraction separation of Am.
Mirvaliev, R.*; Watanabe, Masayuki; Matsumura, Tatsuro; Tachimori, Shoichi*; Takeshita, Kenji*
Journal of Nuclear Science and Technology, 41(11), p.1122 - 1124, 2004/11
Times Cited Count:20 Percentile:76.55(Nuclear Science & Technology)Transmutation is a technology aimed to reduce HLW from reprocessing process. Minor actinides in the HLW will be converted to short-lived nuclides. However, lanthanides in HLW adversely affects on the efficiency of the transmutation. It is well known that separating An(III) and Ln(III) is very difficult because of their similarity of chemical properties. Therefore, the separation is one of the essential subjects to establish the transmutation technology. Considerable efforts have been devoted to the development of new extractants for the separation. N,N,N',N'-tetrakis(2-methylpyridyl)ethylenediamine (TPEN) demonstrates 100-fold preference for Am(III) over Ln(III) between stability constants with the ions in the aqueous phase. We have reported that Am(III) was selectively extracted from the aqueous phase containing Ln(III) by TPEN in nitrobenzene system and synergistic system with TPEN and D2EHPA in octanol. This work presents our recent results that Am(III) is separated from Eu(III) by a synergistic extraction system with TPEN and decanoic acid diluted with 1-octanol.
Tachimori, Shoichi; Suzuki, Shinichi; Sasaki, Yuji
Nihon Genshiryoku Gakkai-Shi, 43(12), p.1235 - 1241, 2001/12
Times Cited Count:29 Percentile:87.17(Nuclear Science & Technology)no abstracts in English
Tachimori, Shoichi
JAERI-Research 2001-048, 23 Pages, 2001/10
A new chemical process, ARTIST process, is proposed for the treatment of spent nuclear fuel. The main concept of the ARTIST process is to recover and stock all actinides (Ans) in two groups, uranium (U) and a mixture of transuranics (TRU), to preserve their resource value and to dispose solely fission products (FPs). The process composed of two main steps, an U exclusive isolation and a total recovery of TRU; which copes with the nuclear non-proliferation measures, and additionally Pu separation process and soft N-donor process if requested, and optionally processes for separation of long-lived FPs. These An products: U-product and TRU-product, are to be solidified by calcination and allowed to the interim stockpile for future utilization. These separations are achieved by use of amidic extractants in accord with the CHON principle. The technical feasibility of the ARTIST process was explained by the performance of both the branched-alkyl monoamides the diglycolic amide (TODGA) in thorough extraction of all TRU by tridentate fashon.
Tachimori, Shoichi
Nihon Genshiryoku Gakkai-Shi, 42(11), p.1124 - 1129, 2000/11
Times Cited Count:1 Percentile:81.71(Nuclear Science & Technology)no abstracts in English
; ; ; ; *
Hoken Butsuri, 21, p.9 - 15, 1986/00
no abstracts in English
Journal of Nuclear Science and Technology, 20(6), p.475 - 490, 1983/00
Times Cited Count:0 Percentile:0.02(Nuclear Science & Technology)no abstracts in English
Kikuchi, Yasuyuki; Nakagawa, Tsuneo; *; *; ; *
JAERI 1268, 142 Pages, 1981/02
no abstracts in English
; H.HAMAGUCHI*; N.ONUMA*; Y.HIRAO*; H.YOKOYAMA*; M.FURUKAWA*
Geochem.Cosmochim.Acta, 33, p.507 - 518, 1969/00
Times Cited Count:34no abstracts in English
Kaminaga, Kiichi; Kanari, Yukiko*; Sakamoto, Yuka*; Noguchi, Miho; Narita, Ayumi*; Fujii, Kentaro; Usami, Noriko*; Kobayashi, Katsumi*; Suzuki, Keiji*; Yokoya, Akinari
no journal, ,
Matsumura, Tatsuro; Ban, Yasutoshi; Hotoku, Shinobu; Suzuki, Hideya; Tsubata, Yasuhiro; Tsutsui, Nao; Morita, Keisuke; Toigawa, Tomohiro; Shibata, Mitsunobu*; Kurosawa, Tatsuya*; et al.
no journal, ,
no abstracts in English
Matsumura, Tatsuro; Ban, Yasutoshi; Hotoku, Shinobu; Suzuki, Hideya; Tsubata, Yasuhiro; Tsutsui, Nao; Morita, Keisuke; Toigawa, Tomohiro; Shibata, Mitsunobu*; Kurosawa, Tatsuya*; et al.
no journal, ,
no abstracts in English
Matsumura, Tatsuro; Ban, Yasutoshi; Hotoku, Shinobu; Suzuki, Hideya; Tsubata, Yasuhiro; Tsutsui, Nao; Morita, Keisuke; Toigawa, Tomohiro; Shibata, Mitsunobu*; Kurosawa, Tatsuya*; et al.
no journal, ,
no abstracts in English
Niihara, Takafumi*; Tsuzuki, Yuki*; Misawa, Keiji*; Yokoyama, Tatsunori; Yoneda, Shigekazu*
no journal, ,
Some brecciated chondrites contain alkaline-rich igneous clasts. Their formational process is explained as early nebular condensates followed by shock melting. The Beardsley chondrite (H5) possesses large amounts of Rb compared to other H chondrites. However, detailed petrological and mineralogical signatures of Beardsley are still lacking and there is no petrological and mineralogical evidence for alteration such as presence of halite/sylvite or other alkaline-rich phases contained in other H chondrites. Here we conduct petrological and mineralogical study for the meteorite, especially to clarify secondary effect(s) and distribution of alkaline elements on the chondrites and discuss the petrogenesis of Beardsley. Petrological and mineralogical features of Beardsley are similar to those observed in impact melted H-chondrites, implying that the grey lithology is a product of impact melting event(s). On the other hand, the higher KO content in the grey lithology cannot be explained only by an impact melting process but is still unclear at this stage.