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Nakase, Masahiko*; Nakazawa, Ryota*; Mishima, Ria
Next Chemical Engineering (Internet), 2, p.100051_1 - 100051_14, 2026/06
Yamamoto, Hajime*; Ochi, Keigo*; Aoyama, Takuya*; Ishii, Kenji*; Matsumura, Daiju; Tsuji, Takuya; Ogushi, Kenya*; Abukawa, Tadashi*
ACS Omega (Internet), 11(14), p.22093 - 22098, 2026/04
Times Cited Count：2 Percentile：75.11(Chemistry, Multidisciplinary)Tanida, Hajime; Okamoto, Yoshihiro; Akiyama, Daisuke*; Kirishima, Akira*
Advances in X-Ray Chemical Analysis, Japan, 57, p.249 - 259, 2026/03
A technique was established for analysing the elemental composition, crystalline phase and chemical state. This was achieved by performing XAFS/XRF/XRD measurements within the same field of view using a microbeam focused to approximately 0.001 mm
. The samples analysed were molybdate crystals precipitating within the sample, known as the yellow phase. This is problematic in the simulated vitrification process for high-level radioactive liquid waste, and simulated fuel debris samples generated in reactor accidents. In the case of the yellow phase samples, it was confirmed that the chemical state of molybdenum differs from that in the glass phase. In the context of the simulated fuel debris samples, which are characterised by multicomponent and multiphase systems where the composition ratio exhibits local variations on the order of tens of micrometers and does not constitute a homogeneous solid solution, it has been confirmed that the chemical state of uranium within the U-rich phase can be selectively determined.
Ozawa, Saki*; Shiozawa, Yudai*; Saijo, Yoshitaka*; Miyajima, Tatsuya*; Matsumura, Daiju; Tsuji, Takuya; Nakase, Masahiko*; Maehara, Terutaka*
Journal of the American Ceramic Society, 109(3), p.e70621_1 - e70621_10, 2026/03
Times Cited Count：1 Percentile：0.00(Materials Science, Ceramics)Matsumura, Daiju; Tsuji, Takuya; Seko, Noriaki*; 5 of others*
Journal of Radioanalytical and Nuclear Chemistry, 335(2), p.1543 - 1552, 2026/02
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)Matsumura, Daiju; Ishii, Kenji*; Tanaka, Hirohisa*; Mizuki, Junichiro*
Hoshako, 39(1), p.28 - 36, 2026/01
no abstracts in English
Wang, M.*; Tsuji, Takuya; Matsumura, Daiju; Sakaushi, Ken*; 9 of others*
Journal of Physical Chemistry C, 130(2), p.931 - 941, 2026/01
Times Cited Count：0 Percentile：0.00(Chemistry, Physical)Ueda, Yuki; Kobayashi, Toru; Nakamura, Satoshi; Ban, Yasutoshi; Kaneta, Yui; Nabatame, Nozomi; Micheau, C.; Tokunaga, Kohei; Nakabe, Rintaro; Kaneko, Masashi*; et al.
Langmuir, 42(1), p.1613 - 1626, 2026/01
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)Understanding the structural factors governing the metal ions selectivity of solvent extraction systems is crucial for developing advanced processes for partitioning and transmutation of high-level radioactive waste. Here, we systematically investigated the effect of alkyl side-chain branching in nitrilotriacetamide (NTAamide) extractants on the extraction of lanthanum (La) and neodymium (Nd), chosen as representative lanthanides. Four extractants having each eight carbon atoms as one of the amide chains with identical molecular weights but different degrees of alkyl branching were examined. Distribution ratios were measured as a function of HNO concentration, and the local coordination structures of La and Nd were analyzed by extended X-ray absorption fine structure (EXAFS), while supramolecular aggregation in the organic phase was characterized by small-angle neutron scattering (SANS). EXAFS analysis revealed that the inner-sphere coordination environment of La and Nd was essentially unaffected by the degree of alkyl branching. In contrast, SANS results showed that extractants with fewer branched alkyl groups formed larger aggregates at low HNO concentrations, particularly in the case of Nd, where aggregation was found to facilitate extraction and prevent precipitation of poorly soluble complexes. These findings demonstrate that alkyl branching strongly influences supramolecular aggregation, which in turn governs extraction behavior. This work highlights the potential of nanoscale structural control as a new design concept for improving selectivity in lanthanide and actinide solvent extraction systems.
MnCoNiCu)VO
Yamamoto, Hajime*; Tsuji, Takuya; Matsumura, Daiju; 16 of others*
Inorganic Chemistry, 64(34), p.17496 - 17502, 2025/08
Times Cited Count：2 Percentile：29.60(Chemistry, Inorganic & Nuclear)
O and/or SiO for methanol synthesis; Deciphering the additive-induced boost in catalytic performance by XAFSIwasaki, Kosei*; Ashida, Yuya*; Matsumura, Daiju; Kawakami, Kotaro*; Shibuya, Kana*; Tazawa, Masaru*; Tsuji, Takuya; Shimizu, Hajime*
Journal of CO Utilization, 97, p.103111_1 - 103111_9, 2025/07
Tanaka, Hirohisa*; Matsumura, Daiju; 8 of others*
International Journal of Hydrogen Energy, 141, p.1317 - 1327, 2025/06
Times Cited Count：2 Percentile：16.37(Chemistry, Physical)Tanaka, Hirohisa*; Matsumura, Daiju; 10 of others*
International Journal of Hydrogen Energy, 141, p.1088 - 1097, 2025/06
Times Cited Count：1 Percentile：16.37(Chemistry, Physical)Tonna, Ryutaro*; Sasaki, Takayuki*; Okamoto, Yoshihiro; Kobayashi, Taishi*
Journal of Nuclear Materials, 612, p.155820_1 - 155820_11, 2025/06
Times Cited Count：3 Percentile：79.61(Materials Science, Multidisciplinary)The dissolution behavior of (U,Zr)O, the primary uranium solid phase in the fuel debris from the Fukushima Daiichi nuclear power plant accidents, was investigated thermodynamically and kinetically under atmospheric conditions. Cubic (U,Zr)O samples with a uniform solid solution of Zr were prepared using wet chemistry methods, and static batch immersion tests were conducted. In strongly acidic conditions, where the solubility of U and Zr exceeded their concentrations, congruent dissolution of both elements was observed with (U,Zr)O dissolving at the same rate as UO. In moderately acidic conditions, where the U solubility was higher than its concentration with Zr reaching a steady state at lower solubility, the U dissolution rate from (U,Zr)O decreased compared to UO. In the presence of oxalic acid, with increased Zr solubility due to the formation of complexes, the U dissolution rate from (U,Zr)O did not decrease. This indicates that Zr in (U,Zr)O formed a secondary solid phase on the solid surface under conditions of lower Zr solubility, which in turn suppressed the oxidative dissolution of U.
Fablet, L.*; P
drot, M.*; Choueikani, F.*; Kieffer, I.*; Proux, O.*; Pierson-Wickmann, A.-C.*; Cagniart, V.*; Yomogida, Takumi; Marsac, R.*
Environmental Science; Nano, 12(5), p.2815 - 2827, 2025/05
Times Cited Count：3 Percentile：58.13(Chemistry, Multidisciplinary)Nickel is an omnipresent trace element in the environment. Due to its high affinity for iron oxide nanoparticles, its elimination from soils and water by these nanoparticles represents an interesting strategy, specially by magnetites, which is naturally present in the environment. However, the interactions between Ni and magnetite are poorly understood, because of the difficulty to control the stoichiometry (Fe(II)-to-Fe(III) ratio) of magnetite. The behavior of Ni in the presence of magnetite nanoparticles with different stoichiometries, in aqueous solution and inert atmosphere, are probed by adsorption experiments and X-ray Absorption Spectroscopy. This study helps predicting the interactions between Ni and magnetite in environmental conditions, which can be used for the development of efficient remediation strategies.
Ueda, Yuki; Micheau, C.; Motokawa, Ryuhei
Fuain Kemikaru, 54(5), p.53 - 60, 2025/05
no abstracts in English
Pt
Ga
with a honeycomb structure using extended X-ray absorption fine structureMatsumoto, Yuji*; Watabe, Yuki*; Iesari, F.*; Osumi, Masakatsu*; Ota, Kyugo*; Haga, Yoshinori; Hatada, Keisuke*; Okajima, Toshihiko*
Metals, 15(4), p.436_1 - 436_13, 2025/04
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary) crystalsTakatori, Sayuri*; Pimon, M.*; Pollitt, S.*; Bartokos, M.*; Beeks, K.*; Gr
neis, A.*; Hiraki, Takahiro*; Homma, Tetsuo*; Hosseini, N.*; Leitner, A.*; et al.
New Journal of Physics (Internet), 27(4), p.043024_1 - 043024_10, 2025/04
Times Cited Count：5 Percentile：76.34(Physics, Multidisciplinary)Recent reports on laser excitation of the low-energy thorium-229 (
Th) nuclear isomeric state in calcium fluoride single crystals render this system a promising candidate for a solid-state nuclear clock. However, experimental characterization of the microscopic ion arrangement around the doped Th and its electronic charge state, crucial for the precise control of the clock transition and assessing the solid-state clock's performance, remains an unresolved task. This study uses X-ray absorption fine structure spectroscopy of Th:CaF to investigate the charge state and coordination environment of doped Th. The results indicate that Th is doped with a 4+ valence at the substitutional site of the Ca
ion, with charge compensated provided by two F
ions located at interstitial sites adjacent to Th.
Tanaka, Hirohisa*; Matsumura, Daiju; 9 of others*
SAE Technical Paper 2025-01-8474 (Internet), 8 Pages, 2025/04
Hamada, Shota*; Matsumura, Daiju; 10 of others*
SAE Technical Paper 2025-01-8476 (Internet), 6 Pages, 2025/04
Yomogida, Takumi; Takahashi, Yoshio*
Chikyu Kagaku, 59(1), p.1 - 10, 2025/03
X-ray absorption fine structure XAFS spectroscopy techniques, which are applicable to almost all elements, provide information on elemental valence and local structure with high elemental selectivity and high sensitivity. It has become an indispensable method in space geochemistry and environmental chemistry. This review presents examples of the application of fluorescence XAFS methods to elements that are difficult to detect by conventional methods, and examples where new chemical species information has been obtained by increasing the energy resolution of the X-ray fluorescence (XRF) detection system to obtain XAFS.
