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Ohashi, Tomonori*; Sakamaki, Tatsuya*; Funakoshi, Kenichi*; Steinle-Neumann, G.*; Hattori, Takanori; Yuan, L.*; Suzuki, Akio*
Journal of Mineralogical and Petrological Sciences (Internet), 120(1), p.240926a_1 - 240926a_13, 2025/06
We explore the structures of dry and hydrated (HO and D
O) Na
Si
O
melt at 0-6 GPa and 1000-1300 K and glasses recovered from high pressure and temperatures by in-situ neutron and X-ray diffraction. The structures of the melts at 0-10 GPa and 3000 K are also investigated by ab-initio molecular dynamics simulation. In-situ neutron experiments revealed that the D-O distance increases with compression due to the formation of -O-D-O- bridging species, which is reproduced by the molecular dynamics simulations. The pressure-induced -O-D-O- formation reflects a more rigid incorporation of hydrogen, which acts as a mechanism for the experimentally observed higher solubility of water in silicate melts. Together with shrinking modifier domains, this process dominates the compression behavior of hydrous Na
Si
O
melt, whereas the compression of dry Na
Si
O
at 0-10 GPa and 3000 K is governed largely by bending of the Si-O-Si angle. The molecular dynamics simulations on hydrous Na
Si
O
melts further suggest that the sodium ions are scavenged from its network-modifying role via 2(
Si-O
+ Na
)
Si-(O-
Si-O)
+ 2Na
and Si-O
+ Na
+ Si-OH
Si-(O-H-O-Si)
+ Na
with increasing pressure.
Tomota, Yo*; Harjo, S.; Xu, P. G.; Morooka, Satoshi; Gong, W.; Wang, Y.*
Metals, 15(6), p.610_1 - 610_19, 2025/05
Times Cited Count:0Aso, Seiyu*; Matsuo, Hiroki*; Yoneda, Yasuhiro; Morikawa, Daisuke*; Tsuda, Kenji*; Oyama, Kenji*; Ishigaki, Toru*; Noguchi, Yuji*
Physical Review B, 111(17), p.174114_1 - 174114_12, 2025/05
We investigate the crystal structures, phase transitions, and phase stability of undoped and Ca-modified NaNbO through a combined analysis of high-resolution synchrotron radiation X-ray and neutron diffraction, convergent-beam electron diffraction, and density functional theory (DFT) calculations. It is demonstrated that the antiferroelectric (AFE)-
phase is stabilized over a wide temperature range of 200 to 800 K by Ca modification, and that the NaNbO
is stabilized by temperature-driven isostatic pressure accompanied by lattice expansion, whereas the Ca-modified NaNbO
is induced by composition-induced chemical pressure along with lattice shrinkage.
Efthimiopoulos, I.*; Klotz, S.*; Kunc, K.*; Baptiste, B.*; Chauvigne, P.*; Hattori, Takanori
Physical Review B, 111(13), p.134103_1 - 134103_13, 2025/04
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)We present a comprehensive study of the high pressure behaviour of ReO using X-ray and neutron diffraction, Raman scattering and first-principles calculations to 15 GPa. We show that the ambient pressure
structure converts at 0.7 GPa in a continuous phase transition directly to a cubic phase with space group
and rhombohedral
structures in this pressure range are an artifact due to an alteration of the sample by high-flux synchrotron X-ray radiation. The structural pressure dependence of the
O samples are presented. The data shed light onto the unusual transition and densification mechanism due to progressive tilting of essentially rigid ReO
octahedra.
Hizukuri, Kyoko*; Fujibuchi, Toshio*; Han, D.*; Arakawa, Hiroyuki*; Furuta, Takuya
Radiological Physics and Technology, 18(1), p.196 - 208, 2025/03
One of the radiation protection measures for medical personnel engaged in X-ray fluoroscopy is the use of radiation-protective plates and a simulation tool to evaluate effect of the plates is desired. Monte Carlo simulation has an advantage of being able to accurately calculate the interaction between radiations and various objects present in the X-ray room. However, Monte Carlo simulation has a disadvantage of being computationally time-consuming. Therefore, we developed a new simplified method to calculate the dose distribution in a short time with the presence of protective plates using pre-computed directional vectors (SCV). Using the Monte Carlo code PHITS, we simulated the ambient dose equivalent distribution the X-ray fluoroscopy room without the presence of protective plates. Assuming the dose at each voxel was all contributed from radiations in the direction indicated by the directional vector, the shielding effect of the protective plates for the dose at the voxel was determined whether the line toward backtrace of the directional vector has a intersect with the protective plate or not. With SCV, the computational time for the whole dose distribution with the presence of a protective plate was reduced approximately 1/6000 of the full PHITS simulation keeping the good accuracy to evaluate the effect of the plate.
Suzuki, Seiya; Katsube, Daiki*; Yano, Masahiro; Tsuda, Yasutaka; Terasawa, Tomoo; Ozawa, Takahiro*; Fukutani, Katsuyuki; Kim, Y.*; Asaoka, Hidehito; Yuhara, Junji*; et al.
Small Methods, 9(3), p.2400863_1 - 2400863_9, 2025/03
Times Cited Count:1 Percentile:30.18(Chemistry, Physical)Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Akutsu, Kazuhiro*; Yamada, Norifumi*; Yamada, Masako*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.
Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05
Times Cited Count:2 Percentile:60.60(Chemistry, Physical)Tsai, Y. H.*; Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kobayashi, Toru; Yamashita, Yoshiyuki*
Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03
Times Cited Count:2 Percentile:57.35(Physics, Applied)Ota, Kyugo*; Watabe, Yuki*; Haga, Yoshinori; Iesari, F.*; Okajima, Toshihiko*; Matsumoto, Yuji*
Symmetry (Internet), 15(8), p.1488_1 - 1488_13, 2023/07
Times Cited Count:2 Percentile:37.80(Multidisciplinary Sciences)Li, H.*; Liu, Y.*; Zhao, W.*; Liu, B.*; Tominaga, Aki; Shobu, Takahisa; Wei, D.*
International Journal of Plasticity, 165, p.103612_1 - 103612_20, 2023/06
Times Cited Count:27 Percentile:94.81(Engineering, Mechanical)In order to clarify the strength properties of Co-free maraging steel, tensile experiment using high energy synchrotron X-ray diffraction was performed. Diffraction profiles from the martensitic and austenitic phases were obtained, and their strength and width were observed to vary as loading. Analysis of the diffraction profiles showed that the content of martensite in the as-aged material decreased slowly at low stress levels and decreased rapidly at high stress levels. On the other hand, the austenite phase in the as-solution materials was significantly transformed the martensite phase as the stress increased. It was clarified to be responsible for their respective strength properties.
Tsai, T.-H.; Sasaki, Shinji; Maeda, Koji
Journal of Nuclear Science and Technology, 60(6), p.715 - 723, 2023/06
Times Cited Count:1 Percentile:14.04(Nuclear Science & Technology)Yamazaki, Yasuhiro*; Shinomiya, Keisuke*; Okumura, Tadaharu*; Suzuki, Kenji*; Shobu, Takahisa; Nakamura, Yuiga*
Quantum Beam Science (Internet), 7(2), p.14_1 - 14_12, 2023/05
Yoshida, Yukihiko
IL Nuovo Cimento, 46(2), p.33_1 - 33_8, 2023/03
Suzuki, Tomoya*; Otsubo, Ukyo*; Ogata, Takeshi*; Shiwaku, Hideaki; Kobayashi, Toru; Yaita, Tsuyoshi; Matsuoka, Mitsuaki*; Murayama, Norihiro*; Narita, Hirokazu*
Separation and Purification Technology, 308, p.122943_1 - 122943_7, 2023/03
Times Cited Count:3 Percentile:15.39(Engineering, Chemical)HNO leaching is used in recycling Pd metal from spent products that primarily contain Ag, and most Pd residues are separated from solutions containing Ag(I). However, a small amount of Pd(II) often remains in these Ag(I) solutions. Therefore, the separation of Pd(II) and Ag(I) in HNO
solutions is essential to promote efficient Pd recycling. In this study, the separation of Pd(II) and Ag(I) in HNO
solutions was investigated using four N-donor-type adsorbents functionalized with amine (R-Amine), iminodiacetic acid (R-IDA), pyridine (R-Py), or bis-picolylamine (R-BPA). R-Amine, R-IDA, and R-Py selectively adsorbed Pd(II) over Ag(I), Cu(II), Ni(II), and Fe(III) from HNO
solutions (0.3-7 M), but R-Amine exhibited a lower Pd adsorption efficiency. In contrast,
90% of Pd(II), Ag(I), and Cu(II) were adsorbed by R-BPA over the entire range of HNO
concentrations. Structural analyses of the adsorbed metal ions using Fourier transform infrared spectroscopy and extended X-ray absorption fine structure spectroscopy revealed the separation mechanisms of the N-donor-type adsorbents. Pd(II) adsorption on R-IDA, R-Py, and R-BPA occurred via Pd(II) coordination of the functional groups (iminodiacetic acid, pyridine, and bis-picolylamine, respectively), whereas that on R-Amine occurred via anion exchange of NO
with [Pd(NO
)
]
. The coordinative adsorption mechanisms resulted in the higher Pd(II) adsorption behaviors of R-IDA, R-Py, and R-BPA. HCl (5.0 M) and thiourea (0.1 M) eluents desorbed 83% of Pd(II) from R-IDA and 95% from R-Py, respectively. R-Py was the most effective Pd(II) adsorbent based on adsorption selectivity and desorption efficiency.
Im, S.*; Jee, H.*; Suh, H.*; Kanematsu, Manabu*; Morooka, Satoshi; Choe, H.*; Nishio, Yuhei*; Machida, Akihiko*; Kim, J.*; Lim, S.*; et al.
Construction and Building Materials, 365, p.130034_1 - 130034_18, 2023/02
Times Cited Count:17 Percentile:77.68(Construction & Building Technology)Wang, Q.*; Hu, Q.*; Zhao, C.*; Yang, X.*; Zhang, T.*; Ilavsky, J.*; Kuzmenko, I.*; Ma, B.*; Tachi, Yukio
International Journal of Coal Geology, 261, p.104093_1 - 104093_15, 2022/09
Times Cited Count:12 Percentile:69.82(Energy & Fuels)Akiyama, Daisuke*; Kusaka, Ryoji; Kumagai, Yuta; Nakada, Masami; Watanabe, Masayuki; Okamoto, Yoshihiro; Nagai, Takayuki; Sato, Nobuaki*; Kirishima, Akira*
Journal of Nuclear Materials, 568, p.153847_1 - 153847_10, 2022/09
Times Cited Count:4 Percentile:51.78(Materials Science, Multidisciplinary)FeUO, CrUO
, and Fe
Cr
UO
are monouranates containing pentavalent U. Even though these compounds have similar crystal structures, their formation conditions and thermal stability are significantly different. To determine the factors causing the difference in thermal stability between FeUO
and CrUO
, their crystal structures were evaluated in detail. A Raman band was observed at 700 cm
in all the samples. This Raman band was derived from the stretching vibration of the O-U-O axis band, indicating that Fe
Cr
UO
was composed of a uranyl-like structure in its lattice regardless of its "x"' value. M
ssbauer measurements indicated that the Fe in FeUO
and Fe
Cr
UO
were trivalent. Furthermore, Fe
Cr
UO
lost its symmetry around Fe
with increasing electron densities around Fe
, as the abundance of Cr increased. These results suggested no significant structural differences between FeUO
and CrUO
. Thermogravimetric measurements for UO
, FeUO
, and CrUO
showed that the temperature at which FeUO
decomposed under an oxidizing condition (approximately 800
C) was significantly lower than the temperature at which the decomposition of CrUO
started (approximately 1250
C). Based on these results, we concluded that the decomposition of FeUO
was triggered by an "in-crystal" redox reaction, i.e., Fe
U
Fe
U
, which would not occur in the CrUO
lattice because Cr
could never be reduced under the investigated condition. Finally, the existence of Cr
in FexCr
UO
effectively suppressed the decomposition of the Fe
Cr
UO
crystal, even at a very low Cr content.
Kowatari, Munehiko*; Nagamoto, Keisuke*; Nakagami, Koichi*; Tanimura, Yoshihiko; Moritake, Takashi*; Kunugita, Naoki*
Journal of Radiation Protection and Research, 47(1), p.39 - 49, 2022/03
Im, S.*; Jee, H.*; Suh, H.*; Kanematsu, Manabu*; Morooka, Satoshi; Koyama, Taku*; Nishio, Yuhei*; Machida, Akihiko*; Kim, J.*; Bae, S.*
Journal of the American Ceramic Society, 104(9), p.4803 - 4818, 2021/09
Times Cited Count:26 Percentile:83.08(Materials Science, Ceramics)Grazzi, F.*; Cialdai, C.*; Manetti, M.*; Massi, M.*; Morigi, M. P.*; Bettuzzi, M.*; Brancaccio, R.*; Albertin, F.*; Shinohara, Takenao; Kai, Tetsuya; et al.
Rendiconti Lincei. Scienze Fisiche e Naturali, 32(3), p.463 - 477, 2021/09
Times Cited Count:6 Percentile:28.63(Multidisciplinary Sciences)