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Tsuji, Takuya; Matsumura, Daiju; Kobayashi, Toru; Yaita, Tsuyoshi
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(1), p.15 - 18, 2023/02
no abstracts in English
Honda, Mitsunori; Kaneta, Yui; Yaita, Tsuyoshi
AIP Advances (Internet), 13(1), p.015314_1 - 015314_6, 2023/01
The efficiency of the sorption of Sr
on weathered biotite, a type of clay minerals was investigated. Removal of Sr and Cs
is important in the treatment of contaminated water from the 1F accident, which is one of the radionuclide waste treatment problems. We focused on developing an adsorption method for Sr ions using weathered biotite, which are abundant in Fukushima. Applying a molten salt treatment, the amount of sorbed Sr simply increased as the added mass ratio of strontium chloride (SrCl
) increased from 1:1, 1:5, and 1:10 for the one-fold, five-fold, and ten-fold additions of SrCl, respectively. Then, the crystal structure of weathered biotite as an adsorbent was evaluated by X-ray diffraction (XRD) analysis. Thus, it was observed that the WB retained its original crystal structure even after the sorption of Sr. Extended X-ray absorption fine structure (EXAFS) analysis was performed to investigate the local sorption structure of Sr in the WB. The results revealed that Sr was preferentially sorbed into the SiO
and AlO
layers when Sr was in the low mass ratio, while, it was mainly sorbed into the SiO layer when the ratio was high.
Np and 
Am gamma ray regionsFukuda, Tatsuo; Kobata, Masaaki; Shobu, Takahisa; Yoshii, Kenji; Kamiya, Junichiro; Iwamoto, Yosuke; Makino, Takahiro*; Yamazaki, Yuichi*; Oshima, Takeshi*; Shirai, Yasuhiro*; et al.
Journal of Applied Physics, 132(24), p.245102_1 - 245102_8, 2022/12
Times Cited Count：0Direct energy conversion has been investigated using Ni/SiC Schottky junctions with the irradiation of monochromatized synchrotron X-rays simulating the gamma rays of Np (30 keV) and Am (60 keV). From current-voltage measurements, electrical energies were obtained for both kinds of gamma rays. The energy conversion efficiencies were found to reach up to 
1.6%, which is comparable to those of a few other semiconducting systems reported thus far. This result shows a possibility of energy recovery from nuclear wastes using the present system, judging from the radiation tolerant nature of SiC. Also, we found different conversion efficiencies between the two samples. This could be understandable from hard X-ray photoelectron spectroscopy and secondary ion mass spectroscopy measurements, suggesting the formation of Ni-Si compounds at the interface in the sample with a poor performance. Hence, such combined measurements are useful to provide information that cannot be obtained by electrical measurements alone.
molecular dynamics simulations reveal the hydration structure of the radium(II) ionYamaguchi, Akiko; Nagata, Kojiro*; Kobayashi, Keita; Tanaka, Kazuya; Kobayashi, Toru; Tanida, Hajime; Shimojo, Kojiro; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08
Times Cited Count：1 Percentile：50.92(Multidisciplinary Sciences)no abstracts in English
Shimojo, Kojiro; Fujiwara, Iori*; Oshima, Tatsuya*; Yokoyama, Keiichi; Yaita, Tsuyoshi
Analytical Sciences, 38(7), p.1003 - 1006, 2022/07
Times Cited Count：0 Percentile：0(Chemistry, Analytical)Liquid-liquid extraction of lanthanide (Ln) ions was investigated using 
-dioctylthiodiglycolamic acid (DOTDGAA), which is a sulfur donor ligand with an amide group and a carboxyl group connected by a thioether chain. The extraction performance and selectivity of DOTDGAA for Ln ions were compared with those of -dioctyldiglycolamic acid (DODGAA), which is also an oxygen donor ligand with a similar chemical structure, to assess the effect of the soft/hard donor atom on Ln separation. DOTDGAA quantitatively extracted all Ln ions while being selective toward light and middle Ln ions, in contrast to the selectivity of DODGAA for heavier Ln ions. Slope analysis demonstrated that the Ln
transfer using DOTDGAA proceeded through a proton-exchange reaction, forming a 1:3 complex, Ln(DOTDGAA). The back-extraction of Ln ions from the extracting phase was successfully achieved under acidic conditions.
Sekiguchi, Tetsuhiro; Yokoyama, Keiichi; Yaita, Tsuyoshi
e-Journal of Surface Science and Nanotechnology (Internet), 20(3), p.186 - 195, 2022/07
Cesium-135 having long life, 2.3 million y, that is contained in nuclear wastes may cause long-term pollution. Technology of isotopic separation of such long lived nuclide is indispensable not only for its volume reduction but also annihilation by nuclear transmutation. The recovery of atomic Cs from molecular CsI is mandatory. We have investigated fullerene C
as a potential absorber for Cs. Angle-resolved X-ray photoelectron spectroscopy, AR-XPS has been used to analyze the depth concentration distribution of Cs. Experiments were performed at soft X-ray beamline BL27A at KEK PF facility. We report on the annealing effect after deposition of Cs and the effect of heating substrate during deposition. For Cs/C sample, the intensity ratio of Cs-3d/C-1s increased in double at the high temperature. This suggests that Cs atoms remain in the material at high temperatures. On the other hand, for CsI/C, the intensity ratio does not change much by elevating temperatures.
Matsuda, Shohei; Yokoyama, Keiichi; Yaita, Tsuyoshi; Kobayashi, Toru; Kaneta, Yui; Simonnet, M.; Sekiguchi, Tetsuhiro; Honda, Mitsunori; Shimojo, Kojiro; Doi, Reisuke; et al.
Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05
Times Cited Count：2 Percentile：50.92(Multidisciplinary Sciences)no abstracts in English
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
Hosha Kagaku, (45), p.28 - 30, 2022/03
no abstracts in English
Suzuki, Tomoya*; Otsubo, Ukyo*; Ogata, Takeshi*; Shiwaku, Hideaki; Kobayashi, Toru; Yaita, Tsuyoshi; Matsuoka, Mitsuaki*; Murayama, Norihiro*; Narita, Hirokazu*
Dalton Transactions (Internet), 50(33), p.11390 - 11397, 2021/09
Times Cited Count：1 Percentile：21.29(Chemistry, Inorganic & Nuclear)no abstracts in English
Simonnet, M.; Kobayashi, Toru; Shimojo, Kojiro; Yokoyama, Keiichi; Yaita, Tsuyoshi
Inorganic Chemistry, 60(17), p.13409 - 13418, 2021/09
Times Cited Count：5 Percentile：73.93(Chemistry, Inorganic & Nuclear)Shimojo, Kojiro; Suzuki, Hideya; Yokoyama, Keiichi; Yaita, Tsuyoshi; Ikeda, Atsushi
Analytical Sciences, 36(12), p.1435 - 1437, 2020/12
Times Cited Count：7 Percentile：48.41(Chemistry, Analytical)Liquid-liquid extraction for the removal of pertechnetate (
TcO
) and perrhenate (ReO) is reported using tripodal extractant 
-hexa-
-octylnitrilotriacetamide (HONTA) composed of three amide groups and a tertiary amine. The extraction behavior was compared with those using alkyldiamideamines (ADAAM(Oct) and ADAAM(EH)), and the commercial amine-type extractant, trioctylamine (TOA). HONTA quantitatively extracted TcO and ReO in the pH range from 1.0 to 2.5 by co-extraction of protons. Extraction performance of extractants was improved in the order of HONTA 
ADAAM(Oct) ADAAM(EH) TOA. TcO and ReO in the extracting phase were successfully stripped using neutral aqueous solutions as the receiving phase, and the extraction ability of HONTA was maintained after five repeated uses.
Orlandi, R.; Hirose, Kentaro; Yaita, Tsuyoshi; Yamagami, Hiroshi; Ieda, Junichi; Kambe, Shinsaku; Ishikawa, Norito
Nihon Genshiryoku Gakkai-Shi ATOMO
, 62(5), p.280 - 284, 2020/05
no abstracts in English
Fe
O
Kobata, Masaaki; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Okane, Tetsuo; Yamagami, Hiroshi; Yaita, Tsuyoshi; Harii, Kazuya; Ieda, Junichi; Okayasu, Satoru; et al.
JPS Conference Proceedings (Internet), 30, p.011192_1 - 011192_6, 2020/03
High energy X-ray photoelectron spectroscopy (HAXPES) measurements were carried out for the Spin Seebeck system Pt/YFeO(YIG). This system was found to show anomalous Hall effect, possible due to the formation of intermetallic compounds between Fe and Pt. To reveal this possibility, we have measured the Fe 1s photoelectron peaks by using HAXPES. It was found that the Fe ions consist of Fe in YIG and metallic Fe. The formation of the metallic state is consistent with the proposed origin of the anomalous Hall effect. Other spectra such as Pt 4f will be presented at the conference.
Simonnet, M.; Suzuki, Shinichi; Miyazaki, Yuji*; Kobayashi, Toru; Yokoyama, Keiichi; Yaita, Tsuyoshi
Solvent Extraction and Ion Exchange, 38(4), p.430 - 440, 2020/00
Times Cited Count：14 Percentile：73.65(Chemistry, Multidisciplinary)Narita, Hirokazu*; Nicolson, R. M.*; Motokawa, Ryuhei; Ito, Fumiyuki*; Morisaku, Kazuko*; Goto, Midori*; Tanaka, Mikiya*; Heller, W. T.*; Shiwaku, Hideaki; Yaita, Tsuyoshi; et al.
Inorganic Chemistry, 58(13), p.8720 - 8734, 2019/07
Times Cited Count：9 Percentile：56.35(Chemistry, Inorganic & Nuclear)Suzuki, Chikashi; Yaita, Tsuyoshi; Suzuki, Shinichi; Pacold, J.*; Altman, A. B.*; Minasian, S. G.*; Tyliszczak, T.*; Shuk, D. K.*; Yoshida, Hiroyuki; Osaka, Masahiko
Journal of Physics and Chemistry of Solids, 127, p.169 - 177, 2019/04
Times Cited Count：3 Percentile：6.16(Chemistry, Multidisciplinary)A combined method of NEXAFS measurement and DFT-calculation was employed for Cs evaluation in clay minerals. The Cs M
NEXAFS spectra of Cs halides were analyzed using the DFT-calculations, and were well reproduced by incorporating the core-hole strength. The Cs M NEXAFS spectrum of clay minerals was well-reproduced by the DFT-calculations including the major transitions and tail structures with the established method. The further evaluation of this spectrum by charge density suggests that these major transitions and the tail structures likely reflect bonding states and local environments around the Cs atoms. Comparison of electronic states of Cs in the clay mineral with those in the Cs halides by DFT-calculations has shown that the interaction between Cs and the nearest-neighbor atom is largest in the clay mineral, because the energy level of Cs-5s and 5p is closer to that of O-2s and 2p than the s and p orbitals of other alkali metal and alkali earth metal elements.
Honda, Mitsunori; Goto, Takuya*; Sakanaka, Yoshihide*; Yaita, Tsuyoshi; Suzuki, Shinichi*
AIMS Electronics and Electrical Engineering (Internet), 3(2), p.102 - 110, 2019/03
The possibility of removal and controlling crystal formation from weathered biotite (WB) in clay minerals were investigated using molten salt electrochemistry (EC) in molten NaCl-CaCl under an electrochemical reductive reaction. Cyclic Voltammogram (CV) measurements were performed in the range of +0.5 V to -2.2 V. Several peaks were confirmed in the CV spectra. The peak at -1.4 V represents a reduction reaction of Fe in WB, so we conducted an experiment at -1.4 V for 2 h to reduce Iron (Fe). The Cs removal rate after EC treatment was determined by X-ray fluorescence analysis, and almost 100% Cs removal was confirmed. To understand the effect of the reductive reaction, we performed X-ray Adsorption Fine Structure (XAFS) analysis. Before EC treatment, the Fe in WB was present as a mixture of Fe and Fe. After EC treatment, the presence of Fe was confirmed by XAFS analysis. Based on this finding, EC treatment is effective for reducing Fe in WB. This result indicated that FeO formation was suppressed, and the reduction reaction was effective for controlling crystal formation.
Ambai, Hiromu; Nishizuka, Yusuke*; Sano, Yuichi; Uchida, Naoki; Iijima, Shizuka; Shiwaku, Hideaki; Yaita, Tsuyoshi
Journal of Nuclear Science and Technology, 56(2), p.193 - 200, 2019/02
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)During the accident that occurred at the Fukushima Daiichi Nuclear Power Plant, a large volume of seawater was introduced as coolant into the storage pools for spent nuclear fuel. If this fuel is reprocessed, some components of seawater will be mixed with the nitric acid solution containing metal ions in the reprocessing process where stainless steels are used as structural material. In this study, we investigated the effect of seawater components in high active liquid waste (HAW) containing nitric acid and metal ions as fission products on the corrosion behavior of SUS316L stainless steel. Corrosion tests were conducted in surrogate HAW containing artificial seawater (ASW). Intergranular corrosion was observed in the HAW with ASW, where Ru increased the corrosion potential to the transpassive region. An increase in the amount of ASW led to a decrease in the corrosion rate and suppression of intergranular corrosion. Interactions between Ru ions and seawater components, such as chloride ions, were indicated by the results of extended Xray absorption fine structure spectroscopy and cyclic voltammetry analyses of the solution containing ASW and HAW.
-hetero donor ligand BIZAKobayashi, Toru; Akutsu, Kazuhiro*; Nakase, Masahiko*; Suzuki, Shinichi; Shiwaku, Hideaki; Yaita, Tsuyoshi
Separation Science and Technology, 54(13), p.2077 - 2083, 2019/02
Times Cited Count：5 Percentile：23.4(Chemistry, Multidisciplinary)Development of separation reagent, which can efficiently separate lanthanides, is of increasing importance because it concerns establishment of purification and recycle techniques rare-earth elements. In our research group, several hetero donor type ligands, which have both oxygen and heterocyclic nitrogen atoms as donor atoms, were developed and revealed that this type of ligands show the selective complexation with specific lanthanide. In this paper, we will discuss the lanthaides complexation properties of the hetero donor type ligand containing benzimidazole group as nitrogen donor (
-methyl--phenyl-2-(1
-benzimidazol-2-yl)-pyridine-6-carboxamide) based on structural investigation by crystallography.
Simonnet, M.; Miyazaki, Yuji*; Suzuki, Shinichi; Yaita, Tsuyoshi
Solvent Extraction and Ion Exchange, 37(1), p.81 - 95, 2019/00
Times Cited Count：4 Percentile：22.61(Chemistry, Multidisciplinary)