Analysis on sorption structure of cesium in clay minerals under dry/wet condition

Tsuji, Takuya; Matsumura, Daiju; Kobayashi, Toru

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 12(5), p.259 - 262, 2024/10

https://doi.org/10.18957/rr.12.5.259

no abstracts in English

Local and electronic structures of NaNbO, AgNbO, and KNbO

Yoneda, Yasuhiro; Kobayashi, Toru; Tsuji, Takuya; Matsumura, Daiju; Saito, Yuji; Noguchi, Yuji*

Japanese Journal of Applied Physics, 63(9), p.09SP12_1 - 09SP12_10, 2024/09

https://doi.org/10.35848/1347-4065/ad72fc

NaNbO, AgNbO, and KNbO with ABO-type perovskite system is known to possess good ferroelectric properties. We directly determined the rattling space of each atom through local structure analysis. This analysis revealed the bonding sites with large fluctuations varied with varying ion size. Experimental evidence including soft X-ray absorption spectroscopy, indicates that the A-site ions are hybridized with oxygen.

Local structure analysis of BiNaTiOBaTiO solid solutions

Yoneda, Yasuhiro; Kobayashi, Toru; Tsuji, Takuya; Matsumura, Daiju; Saito, Yuji; Noguchi, Yuji*

Japanese Journal of Applied Physics, 62(SM), p.SM1006_1 - SM1006_8, 2023/11

https://doi.org/10.35848/1347-4065/ace3cd

BiNaTiOBaTiO (BNTBT) solid solutions have been extensively studied because they exhibit good piezoelectric properties. In addition, a wide variety of phases are observed depending on the BT composition. Soft X-ray absorption spectroscopy and high-energy X-ray diffraction experiments of BNTBT solid solutions were performed using synchrotron radiation. From the electronic structure and local structure of BNTBT solid solution, the substitution effect of BT occurred mainly at the A site, which is the substitution site of Ba. The rhombohedral strain of the TiO octahedron did not change with the change in BT composition, suggesting that the change in the electronic structure at the O- absorption edge is due to the change in the hybridization state.

Local atomic displacements and sign of the structural transformation in medium-entropy alloys observed in extended X-ray absorption fine structure spectra

Ikeda, Yoichi*; Umemoto, Yoshihiko*; Matsumura, Daiju; Tsuji, Takuya; Hashimoto, Yuki*; Kitazawa, Takafumi*; Fujita, Masaki*

Materials Transactions, 64(9), p.2254 - 2260, 2023/09

https://doi.org/10.2320/matertrans.MT-M2023043

Sorption structure of cesium in various clay minerals by Cs -edge XAFS measurement

Tsuji, Takuya; Matsumura, Daiju; Kobayashi, Toru

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(4), p.214 - 217, 2023/08

https://doi.org/10.18957/rr.11.4.214

no abstracts in English

Uranium hydroxide/oxide deposits on uranyl reduction

Ouchi, Kazuki; Matsumura, Daiju; Tsuji, Takuya; Kobayashi, Toru; Otobe, Haruyoshi; Kitatsuji, Yoshihiro

RSC Advances (Internet), 13(24), p.16321 - 16326, 2023/05

https://doi.org/10.1039/D3RA02899B

We clarified the chemical state transformation of deposits following the reduction of uranyl ion (UO) from the results of electrochemical quartz crystal microbalance, impedance spectra and X-ray absorption fine structure measurements. We propose the following deposition mechanism: (1) U is formed by the disproportionation of U. (2) U forms U hydroxide deposits, and (3) finally, the hydroxide deposits transform into U oxide, generally having a larger electrical resistance than the former.

Sorption structure of cesium ions for weathered biotite and kaolinite

Tsuji, Takuya; Matsumura, Daiju; Kobayashi, Toru; Yaita, Tsuyoshi

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(1), p.15 - 18, 2023/02

https://doi.org/10.18957/rr.11.1.15

no abstracts in English

Uranium chelating ability of decorporation agents in serum evaluated by X-ray absorption spectroscopy

Uehara, Akihiro*; Matsumura, Daiju; Tsuji, Takuya; Yakumaru, Haruko*; Tanaka, Izumi*; Shiro, Ayumi*; Saito, Hiroyuki*; Ishihara, Hiroshi*; Homma-Takeda, Shino*

Analytical Methods, 14(24), p.2439 - 2445, 2022/06

https://doi.org/10.1039/D2AY00565D

Dispersive XAFS Study on the Laser-Induced Reduction of a Rh ion complex; Presence of a Rh Intermediate in Direct Photoreduction

Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

Journal of Physical Chemistry C, 126(12), p.5607 - 5616, 2022/03

https://doi.org/10.1021/acs.jpcc.1c10160

The reaction mechanism of the direct photoreduction of a Rh ion complex to a Rh species induced by pulsed ultraviolet laser irradiation was studied using dispersive X-ray absorption fine structure (DXAFS) spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points and suggested that more than two Rh species contribute toward the direct photoreduction of Rh. Analysis of the time-resolved XANES data by singular value deposition showed that the direct photoreduction involves three Rh species. Multivariate curve resolution by alternating least-squares analysis (MCR-ALS) of the time-resolved XANES data gave pure spectra and concentration profiles of the three Rh species. The Rh species were assigned to Rh, Rh, and Rh species based on the features of the pure XANES spectra. The concentration profiles suggested that the direct photoreduction proceeds in the order of Rh Rh Rh. A reaction mechanism, which was proposed involving photoreductions of Rh and Rh, photoinduced autocatalytic reductions of Rh and Rh, and photooxidation of Rh, well reproduced the concentration profiles of three Rh species.

Commissioning of X-ray micro beam by Kirkpatrick-Baez (KB) mirror

Tanida, Hajime; Tsuji, Takuya; Kobata, Masaaki

JAEA-Technology 2021-031, 25 Pages, 2022/02

JAEA-Technology-2021-031.pdf:2.3MB

In the decommissioning of the Tokyo Electric Power Company Holdings Fukushima Daiichi Nuclear Power Station, analysis of fuel debris to understand its characteristics is very important. The fuel debris removed for testing and analyzing will be fine particulates. Non-destructive analytical methods using X-rays are effective for such samples, but in order to apply them to fine particles, the X-rays must be focused to the micrometer order. For this purpose, the Kirkpatrick-Baez (KB) mirror was introduced. In this paper, we record the selection, specification, adjustment of the mirror, and write down the example of mapping of elements and evaluation of their valence by this mirror.