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Namie, Masanari; Saito, Junichi
Computational Materials Science, 239, p.112963_1 - 112963_7, 2024/04
Nankawa, Takuya; Sekine, Yurina; Matsumura, Daiju; Hiroi, Kosuke; Takata, Shinichi; Kamiya, Yoshimi*; Honda, Takayuki*
Langmuir, 40(11), p.5725 - 5730, 2024/03
Times Cited Count：0The chemical reaction between Fe and lacquer has been used to create the black color lacquer since ancient times. Here, the chemical state of Fe ions in black lacquer was investigated by using X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and Fourier transform-infrared (FT-IR) spectroscopy. Fe(II) or Fe(III) was added to the lacquer paste to prepare black lacquer films by air drying, heating, or UV irradiation. The XANES spectral features of all the film samples were similar, meaning that the Fe ions in the samples existed in the trivalent state regardless of the oxidation state of the initially added Fe. The corresponding Fourier transforms of the EXAFS spectra around the Fe K-edge were used to investigate Fe sites in the lacquer films. The spectra of all the film samples were similar shapes, but the peak intensities decreased in the order air dried 
heated UV irradiated films. This result indicates that heating and UV irradiation made the coordination structure of Fe in the lacquer non-uniform, and that heating caused the greatest non-uniformity. The complementary use of XANES, XAFS, and FT-IR spectroscopy is highly effective for non-destructive analysis of black lacquer in precious cultural artifacts.
-FeSuzudo, Tomoaki; Ebihara, Kenichi; Tsuru, Tomohito; Mori, Hideki*
Journal of Applied Physics, 135(7), p.075102_1 - 075102_7, 2024/02
Fracture of body centred cubic (bcc) metals and alloys below the ductile-to-brittle transition temperature is brittle. This is theoretically explained by the notion that the critical stress intensity factor of a given crack front for brittle fracture is smaller than that for plasticdeformation; hence, brittle fracture is chosen over plastic deformation. Although this view is true from a macroscopic point of view, such brittle fracture is always accompanied by small-scale plastic deformation in the vicinity of the crack tip, i.e. crack tip plasticity. This short paper investigates the origin of this plasticity using atomistic modeling with a recently developed machine-learning interatomic potential of -Fe. The computational results identified the precursor of crack tip plasticity, i.e. the group of activated atoms dynamically nucleated by fast crack propagation.
Xu, P. G.; Zhang, S.-Y.*; Harjo, S.; Vogel, S. C.*; Tomota, Yo*
Quantum Beam Science (Internet), 8(1), p.7_1 - 7_13, 2024/01
Zhou, L.*; Zhang, H.*; Qin, T. Y.*; Hu, F. F.*; Xu, P. G.; Ao, N.*; Su, Y. H.; He, L. H.*; Li, X. H.*; Zhang, J. R.*; et al.
Metallurgical and Materials Transactions A, 11 Pages, 2024/00
Times Cited Count：0Mori, Michiyasu; Ziman, T.*
IEEE Transactions on Magnetics, 59(11), p.1300505_1 - 1300505_5, 2023/11
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Shibata, Daisuke*; Kojima, Kazuo*; Hasegawa, Takehiko*; Sato, Seiichi*; Fukaya, Akane*; Hatakeyama, Kiyoshi*
JAEA-Research 2023-004, 45 Pages, 2023/09
JAEA-Research-2023-004.pdf:6.07MB
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. To understand the chemical stability of simulated waste glasses, XANES spectra of B K-edge, Fe L
, L
-edge, and Cs M
, M
-edge were measured on the glass surface exposed to the leachate. As a result, it was found that the glass surface exposed to the leachate was changed and it was difficult to obtain a clear XANES spectrum. From the B K-edge XANES spectra on glass surfaces exposed to the leachate, an increase in three-coordination of B-O (BO) and a decrease in four-coordination of B-O (BO) were observed compared to the glass surfaces before immersion. The XANES spectra of Fe L, L-edge, and Cs M, M-edge show that as the exposure time in the leachate increases, the Cs present on the glass surface dissolves into the leachate. The XANES spectra of Si K-edge were measured on simulated waste glass surfaces before immersion, and it was confirmed that the change in XANES spectra given by NaO concentration had a larger effect than the waste component concentration.
Ni
D
at high 
conditionsShito, Chikara*; Kagi, Hiroyuki*; Kakizawa, Sho*; Aoki, Katsutoshi*; Komatsu, Kazuki*; Iizuka, Riko*; Abe, Jun*; Saito, Hiroyuki*; Sano, Asami; Hattori, Takanori
American Mineralogist, 108(4), p.659 - 666, 2023/04
Times Cited Count：1 Percentile：64.83(Geochemistry & Geophysics)The phase relation and crystal structure of FeNiH (D) at high pressures and temperatures up to 12 GPa and 1000 K were clarified by in-situ X-ray and neutron diffraction measurements. Under conditions of the present study, no deuterium atoms occupied tetragonal (
) sites of face-centered cubic (fcc) FeNiD unlike fcc FeH(D). The deuterium-induced volume expansion per deuterium 
was determined as 2.45(4) 
and 3.31(6) for fcc and hcp phases, respectively, which were significantly larger than the corresponding values for FeD. The value slightly increased with increasing temperature. This study suggests that only 10% of nickel in iron drastically changes the behaviors of hydrogen in metal. Assuming that is constant regardless of pressure, the maximum hydrogen content in the Earth's inner core is estimated to be one to two times the amount of hydrogen in the oceans.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.
Journal of Nuclear Science and Technology, 60(4), p.435 - 449, 2023/04
Times Cited Count：3 Percentile：68.71(Nuclear Science & Technology)Double-differential thick target neutron yields (TTNYs) for Fe, Pb, and Bi targets induced by 107-MeV protons were measured using the fixed-field alternating gradient accelerator at Kyoto University for research and development of accelerator-driven systems (ADSs) and fundamental ADS reactor physics research at the Kyoto University Critical Assembly (KUCA). Note that TTNYs were obtained with the time-of-flight method using a neutron detector system comprising eight neutron detectors; each detector has a small NE213 liquid organic scintillator and photomultiplier tube. The TTNYs obtained were compared with calculation results using Monte Carlo-based spallation models (i.e., INCL4.6/GEM, Bertini/GEM, JQMD/GEM, and JQMD/SMM/GEM) and the evaluated high-energy nuclear data library, i.e., JENDL-4.0/HE, implemented in the particle and heavy iontransport code system (PHITS). All models, including JENDL-4.0/HE, failed to predict high-energy peaks at a detector angle of 5
. Comparing the energy- and angle-integrated spallation neutron yields at energies of 
20 MeV estimated using the measured TTNYs and the PHITS indicated that INCL4.6/GEM would be suitable for the Monte Carlo transport simulation of ADS reactor physics experiments at the KUCA.
Ao, N.*; Zhang, H.*; Xu, H. H.*; Wu, S. C.*; Liu, D.*; Xu, P. G.; Su, Y. H.; Kang, Q. H.*; Kang, G. Z.*
Engineering Fracture Mechanics, 281, p.109166_1 - 109166_14, 2023/03
Times Cited Count：4 Percentile：85.05(Mechanics)Yanagida, Akinobu*; Ura, Yoko*; Mitsui, Seiichiro; Ishidera, Takamitsu; Kawakita, Ryohei
Nara Bunkazai Kenkyujo Soritsu 70-Shunen Kinen Rombunshu; Bunkazai Ronso 5, p.843 - 856, 2023/03
To investigate chloride salt accumulation inside an iron artifact in soil, non-destructive analysis of three iron artifacts excavated from the Heijo Palace Site was conducted using elemental mapping by X-ray fluorescence analysis, micro-X-ray diffraction analysis, and X-ray computed tomography. Furthermore, the buried environments of the artifacts were presumed based on the previous reports of the environmental investigation at the Heijo Palace site. The results revealed the iron artifact's corrosion behavior was different individually- (1) the iron artifact that was presumed buried under oxidation environments had a goethite/magnetite corrosion layer and contained akageneite inside the corrosion layer. (2) the metal of the other iron artifacts buried under the oxidation environment had eluted absolutely and the artifacts had a rust layer formed by only goethite. (3) the other artifact buried in reduction environments had a rust layer composed of siderite. Accumulation of chloride salts inside an iron artifact was observed only in (1). Because each Cl
concentration measured in underground water observation holes at the Heijo Palace Site showed almost the same level concentrations, it was presumed that the accumulation of chloride salts depended on the environmental factor except for Cl concentration. Based on these results, there was a possibility that the occurrence of local corrosion attributed to the separation of anodic and cathodic regions through the formation of the goethite/magnetite rust layer caused chloride salts accumulation inside an iron artifact.
Yabuuchi, Kiyohiro*; Suzudo, Tomoaki
Journal of Nuclear Materials, 574, p.154161_1 - 154161_6, 2023/02
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)In nuclear materials, irradiation defects cause degradation of mechanical properties. In these materials, the relationship between dislocations and voids is particularly important for mechanical strength. Although only spherical voids have been studied in the past, this study focuses on faceted voids, which are observed simultaneously with spherical voids. In the current study, molecular dynamics was used to analyze the effect of faceted voids in the irradiation hardening of pure iron. Specifically, we clarified the difference in obstacle strength and interaction processes between spherical voids and faceted voids, and that even faceted voids show differences in interaction depending on their crystallographic arrangement with dislocations.
Zhang, H.*; Wu, S. C.*; Ao, N.*; Zhang, J. W.*; Li, H.*; Zhou, L.*; Xu, P. G.; Su, Y. H.
International Journal of Fatigue, 166, p.107296_1 - 107296_11, 2023/01
Times Cited Count：4 Percentile：61.91(Engineering, Mechanical)Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2022-008, 37 Pages, 2022/10
JAEA-Research-2022-008.pdf:5.27MB
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of simulated waste glass surfaces after immersion test to investigate the long chemical stability. (1) As the leaching time of glass samples in immersion test passed, the Cs M, M-edge XANES spectra disappeared and the Fe L, L-edge spectra changed. (2) A new compound was formed on the sample surface after the immersion test, and these changes in the surface state were confirmed by Raman spectroscopy. However, it became difficult to obtain a clear B K-edge XANES spectrum by forming a compound on glass surfaces. The Si K-edge XANES spectra of borosilicate glass frits with different NaO content were measured, and following was confirmed. (1) As the NaO concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The intensity of the Si K-edge peak is maximum when the NaO content in glass frits was about 7wt%.
Kobayashi, Kensuke*; Yasue, Ayumu*; Morooka, Satoshi; Kanematsu, Manabu*
Konkurito Kogaku Nenji Rombunshu (DVD-ROM), 44(1), p.208 - 213, 2022/07
no abstracts in English
Igarashi, Takahiro; Otani, Kyohei; Komatsu, Atsushi; Kato, Chiaki; Sakairi, Masatoshi*
Bosei Kanri, 66(4), p.141 - 145, 2022/04
Metal corrosion is a material deterioration phenomenon based on electrochemical reactions on an atomic scale. In this paper, various methods for acquiring physical properties on metal surfaces using first-principles calculations were described. As examples of applying first-principles calculation to metal corrosion, the effect of hydrogen adsorption on the metal surface on the potential change and the effect of cation atoms in the aqueous solution on the corrosion resistance of the metal were reported.
Nagai, Takayuki; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*; Arima, Tatsumi*
Photon Factory Activity Report 2021 (Internet), 2 Pages, 2022/00
no abstracts in English
Otani, Kyohei; Kato, Chiaki
Zairyo To Kankyo, 70(12), p.480 - 486, 2021/12
This is a comprehensive paper of the corrosion of carbon steel in air/solution alternating condition. From cross-sectional observation and analysis of the iron rust layer formed on the surface of carbon steel in the alternating condition, it was found that a multilayered iron rust layer composed of red rust layer (
-FeOOH), rust crust layer (FeO), inner crystal (FeO), and inner rust layer was formed on carbon steel. The multi-layered iron rust layer would accelerate the cathodic oxygen reduction reaction, and the reason why the corrosion rate of the carbon steel in the alternating condition was accelerated. The effect of artificial seawater (ASW) composition on the corrosion rate of carbon steel in air/solution alternating condition was investigated. It was found that the corrosion rate increased with increasing concentration from pure water to 200 times diluted ASW, and decreased with increasing concentration from 20 times diluted ASW to no diluted ASW. The Mg and Ca ions in ASW precipitated on the reaction interface and formed a metal cation layer, which inhibited the oxygen reduction reaction, and thus the corrosion of carbon steel was inhibited in the highly concentrated ASW.
Shamoto, Shinichi; Ieda, Junichi
CROSS T&T, (69), p.35 - 39, 2021/10
no abstracts in English
Harjo, S.; Kawasaki, Takuro; Tsuchida, Noriyuki*; Morooka, Satoshi; Gong, W.
Tetsu To Hagane, 107(10), p.887 - 896, 2021/10
Times Cited Count：0 Percentile：0(Metallurgy & Metallurgical Engineering)