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Journal Articles

Prediction of stability constants for novel chelates design in minor actinides partitioning over lanthanides using density functional theory calculation

Kaneko, Masashi; Sasaki, Yuji; Wada, Eriko*; Nakase, Masahiko*; Takeshita, Kenji*

Chemistry Letters, 50(10), p.1765 - 1769, 2021/10

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

Density functional theory calculation is applied to predict the stability constants for Eu$$^{3+}$$ and Am$$^{3+}$$ complexes in aqueous solution for molecular modelling of novel separation agents for minor actinides over lanthanides. Logarithm of experimental stability constants correlates with calculated complex formation enthalpies with high reproducibility (R$$^{2}$$ $$>$$ 0.98). Prediction of stability constants of novel chelates is demonstrated and indicates a potential availability of the derivatives of diethylenetriaminepentaacetic acid type chelate in acidic condition and enhancement of Am$$^{3+}$$ selectivity over Eu$$^{3+}$$.

Journal Articles

Chemical form analysis of reaction products in Cs-adsorption on stainless steel by means of HAXPES and SEM/EDX

Kobata, Masaaki; Okane, Tetsuo; Nakajima, Kunihisa; Suzuki, Eriko; Owada, Kenji; Kobayashi, Keisuke*; Yamagami, Hiroshi; Osaka, Masahiko

Journal of Nuclear Materials, 498, p.387 - 394, 2018/01

 Times Cited Count:16 Percentile:85.51(Materials Science, Multidisciplinary)

In this study, for the understandings of Cesium (Cs) adsorption behavior on structure materials in severe accidents at a light water nuclear reactor, the chemical state of Cs and its distribution on the surface of SUS304 stainless steel (SS) with different Si concentration were investigated by hard X-ray photoelectron spectroscopy (HAXPES) and scanning electron microscope / energy dispersive X-ray spectroscopy (SEM/EDX). As a result, it was found that Cs is selectively adsorbed at the site where Si distributes with high concentration. CsFeSiO$$_{4}$$ is a dominant Cs products in the case of low Si content, mainly formed, while Cs$$_{2}$$Si$$_{2}$$O$$_{5}$$ and Cs$$_{2}$$Si$$_{4}$$O$$_{9}$$ are formed in addition to CsFeSiO$$_{4}$$ in the case of high Si content. The chemical forms of the Cs compounds produced in the adsorption process on the SS surface has a close correlation with the concentration and chemical states of Si originally included in SS.

Journal Articles

Devil's flower resulting from a successive charge disproportionation of NaV$$_{2}$$O$$_{5}$$; Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloom

Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi*; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.

Hoshako, 21(2), p.87 - 96, 2008/03

Devil's flower has been found in a temperature-pressure phase diagram of NaV$$_{2}$$O$$_{5}$$, which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an X-ray structural analysis and a resonant X-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaV$$_{2}$$O$$_{5}$$. The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that it is the first time that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between a Ising spins may result from the Ising spin-phonon coupling.

Journal Articles

Structural relations between two ground states of NaV$$_{2}$$O$$_{5}$$ under high pressure; A Synchrotron X-ray diffraction study

Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.

Physical Review B, 76(9), p.094113_1 - 094113_10, 2007/09

 Times Cited Count:10 Percentile:44.59(Materials Science, Multidisciplinary)

Structural relations between two ground states of the ANNNI (Axial Next Nearest Neighbor Ising) compound NaV$$_{2}$$O$$_{5}$$, C$$_{1/4}$$- and C$$_{0}$$-phases below and above the transition pressure $$P_{rm C}$$ = 1 GPa, were investigated by X-ray diffraction and scattering techniques. The structure of the C$$_{0}$$-phase is well explained by the $$A$$($$A'$$) pattern which is one of four layers ($$AAA'A'$$) of the C$$_{1/4}$$-phase, however, the amount of the atomic shifts under the conditions 1.6 GPa and 6 K is 27% that under ambient pressure. On the other hand, resonant X-ray scattering showed that the charges are disproportionated under high pressure. Based on these facts, it was concluded that charge disproportionation corresponds to the Ising variable in NaV$$_{2}$$O$$_{5}$$, where the atomic shifts are regarded as linearly coupled to the Ising spins. These results lead to the hypothesis that the competitive interactions between the Ising spins may result from the Ising spin-phonon coupling.

Journal Articles

Effect of the heat treatment conditions onto characteristics of Chromium-Zirconium Copper

Aoki, Shoji*; Wada, Masahiko*; Yamaji, Tetsuo*; Mori, Kensuke; Enoeda, Mikio; Hirose, Takanori; Suzuki, Kazuhiko

Do To Dogokin, 45(1), p.125 - 130, 2006/08

Chromium-zirconium copper (Cu-Cr-Zr) as precipitation hardened copper alloy is examined as one of the structural materials used for the ITER in vacuum vessel components (blanket and divertor etc.). The precipitation hardening in Cu-Cr-Zr is made by the solution treatment with rapid cooling to obtain the supersaturated solid solution of chromium and zirconium in copper, and the subsequent aging treatment to grow the refined precipitate consists of chromium and zirconium respectively. While the parts have been assembled and used by copper alloys already precipitation hardened in general use, the blanket parts will be done by the innovative method with the thermomechanical treatment set of the precipitation hardening at the same time as dissimilar material junction in the ITER blanket. In this research, the mechanical and electrical conductivity properties change was investigated under the wide range of thermomechanical treartment conditions in order to comprehend the conditions necessary to fulfill the excellent characteristics in Cu-Cr-Zr. Therefore, the influence of the quenching cooling rate condition after solution treatment and the other conditions on Cu-Cr-Zr was inspected by measuring electrical conductivity as the indication of the solution treatment state i.e. the supersaturated solid solution or the precipitation state and measuring the tensile test properties of the specimens that are prepared by the set of the solution treatments with some quenching cooling rate conditions and following aging treatments.

Journal Articles

Discovery of the "Devil's flower" in a charge-ordering system; Synchrotron X-ray diffraction study of NaV$$_{2}$$O$$_{5}$$

Owada, Kenji; Fujii, Yasuhiko; Nakao, Hironori*; Murakami, Yoichi*; Isobe, Masahiko*; Ueda, Yutaka*

Modern Physics Letters B, 20(5), p.199 - 214, 2006/02

 Times Cited Count:5 Percentile:21.81(Physics, Applied)

We review recent synchrotron diffraction studies of NaV$$_{2}$$O$$_{5}$$. The resonant X-ray scattering performed on a monoclinically-split single domain of NaV$$_{2}$$O$$_{5}$$ shows a critically enhanced contrast between V$$^{4+}$$ and V$$^{5+}$$ ions. The results has led us to the unequivocal conclusion of the charge-order pattern of low-temperature phase of NaV$$_{2}$$O$$_{5}$$ below $$T_{rm c}$$ = 35 K. In spite of the possible four types of configuration of the zig-zag-type charge-order patterns in the $$ab$$-plane (A, A', B and B'), the stacking sequence along the $$c$$-axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins $$uparrow$$ and $$downarrow$$, one can reasonably explain the previously discovered "devil's staircase"-type behavior with respect to the modulation of layer-stacking sequences at high pressures and low temperatures, which clearly resembles the global phase diagram theoretically predicted by the ANNNI model, called "devil's flower". This is the first case that the devil's flower appears in such a charge-ordering system, where charge-order patterns are regarded as Ising spins.

Journal Articles

Charge-order pattern of the low-temperature phase from a monoclinic single domain of NaV$$_{2}$$O$$_{5}$$ uniquely determined by resonant X-ray scattering

Owada, Kenji; Fujii, Yasuhiko; Katsuki, Yuya*; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Sawa, Hiroshi*; Ninomiya, Emi*; Isobe, Masahiko*; Ueda, Yutaka*

Physical Review Letters, 94(10), p.106401_1 - 106401_4, 2005/03

 Times Cited Count:24 Percentile:72.2(Physics, Multidisciplinary)

The present resonant X-ray scattering has been performed on a monoclinically-split single domain of NaV$$_{2}$$O$$_{5}$$. The observation of a critically enhanced contrast between V$$^{4+}$$ and V$$^{5+}$$ ions has led us to the unequivocal conclusion of the charge-order pattern of low-temperature phase of NaV$$_{2}$$O$$_{5}$$ below $$T_{rm c}$$ = 35 K. In spite of the possible four types of configuration of the zig-zag-type charge-order patterns in the $$ab$$-plane (A, A', B and B'), the stacking sequence along the $$c$$-axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins, one can reasonably explain the previously discovered "devil's staircase"-type behavior with respect to the modulation of layer-stacking sequences at high pressures and low temperatures, which clearly resembles the global phase diagram theoretically predicted by the ANNNI model.

JAEA Reports

Corrosion Resistance of Titanium for Nuclear Waste Container in Non-oxidizing Condition (II)

Wada, Ryutaro*; Nishimura, Tsutomu*; Shimogori, Kazutoshi*; Tomari, Haruo*; Masugata, Tsuyoshi*; Shimoda, Hideaki*; Fujiwara, Kazuo*; Nishimoto, Hidetoshi*; Oda, Masashi*

PNC TJ1058 98-002, 159 Pages, 1998/02

PNC-TJ1058-98-002.pdf:12.95MB

None

JAEA Reports

Corrosion Resistance of Titanium for Nuclear Waste Container in Non-oxidizing Condition (II)

Wada, Ryutaro*; Nishimura, Tsutomu*; Shimogori, Kazutoshi*; Tomari, Haruo*; Masugata, Tsuyoshi*; Shimoda, Hideaki*; Fujiwara, Kazuo*; Nishimoto, Hidetoshi*; Oda, Masashi*

PNC TJ1058 98-001, 446 Pages, 1998/02

PNC-TJ1058-98-001.pdf:36.59MB

None

JAEA Reports

Corrosion Resistance of Titanium for Nuclear Waste Container in Non-oxidizing Condition (I)

*; Nishimura, Tsutomu*; Shimogori, Kazutoshi*; *; Fujiwara, Kazuo*; *; *

PNC TJ1058 97-005, 49 Pages, 1997/03

PNC-TJ1058-97-005.pdf:5.06MB

None

JAEA Reports

Corrosion Resistance of Titanium for Nuclear Waste Container in Non-oxidizing Condition (I)

*; Nishimura, Tsutomu*; Shimogori, Kazutoshi*; *; Fujiwara, Kazuo*; *; *

PNC TJ1058 97-004, 179 Pages, 1997/03

PNC-TJ1058-97-004.pdf:19.14MB

None

Oral presentation

Effect of the thermomechanical treatment conditions onto characteristics of chromium-zirconium copper after the solution treatment

Hada, Kazuhiko; Nishi, Hiroshi; Hirose, Takanori; Mori, Kensuke; Aoki, Shoji*; Wada, Masahiko*; Yamamichi, Tetsuo*

no journal, , 

Chromium-zirconium copper as precipitation hardened copper alloy is examined as one of the structural materials used for the ITER in vacuum vessel components. The process that consists of a thermomechanical treatments series of the solution treatment with rapid cooling to obtain the supersaturated solid solution and the aging treatment etc., is adopted in order to obtain the demanded high strength in manufacturing of this alloy material. However, as this alloy is precipitation hardened copper alloy, it is concerned that the great change in the strength characteristic is caused by the thermomechanical treatments conditions, especially the difference of the quenching cooling rate after the solution treatment in manufacturing. In this research, the influence of the quenching cooling rate condition after the solution treatment and the other conditions on this copper alloy was investigated by measuring the tensile test properties of the specimens that are prepared by treatments with some quenching cooling rate conditions after the solution treatment and aging treatment. One of the typical results from this study is that, for the quenching cooling rate after the solution treatment, it was understood that the cooling rate change from 1 to 10$$^{circ}$$C/s causes the great growth in the tensile strength. Therefore, when this alloy component is manufactured by heat history process like HIP process and needed to be treated solution treatment to be use for the structural component, it is important to guarantee the strength of the product by checking the quenching cooling rate after the solution treatment.

Oral presentation

Relationship between phase transformation in SUS304 stainless steel and strain stored in it during creep tests

Shiraki, Atsuhiro*; Wada, Takumi*; Murata, Yoshinori*; Morinaga, Masahiko*; Takaya, Shigeru; Koyama, Toshiyuki*

no journal, , 

no abstracts in English

Oral presentation

Chemical state of adsorbed Cesium under LWR severe accident studied by hard X-ray photoelectron spectroscopy

Kobata, Masaaki; Okane, Tetsuo; Kobayashi, Keisuke*; Owada, Kenji*; Nakajima, Kunihisa; Suzuki, Eriko; Osaka, Masahiko

no journal, , 

To understand the chemisorption behavior of Cesium (Cs) under an LWR severe accident, we have studied the Cs chemisorbed surfaces of the simulation samples (stainless steel) by hard X-ray photoelectron spectroscopy (HAXPES). It was found that the chemical states of Cs adsorbed on the sample surface were varied in dependence upon a silicon concentration of sample.

Oral presentation

Upgrading of hard X-ray photoelectron spectroscopy for chemical state analysis of environmental samples collected around Fukushima Daiichi Nuclear Power Plant

Kobata, Masaaki; Satou, Yukihiko; Okane, Tetsuo; Kawasaki, Ikuto; Yoshii, Kenji; Fukuda, Tatsuo; Osaka, Masahiko; Owada, Kenji*

no journal, , 

In order to enable chemical state analysis by hard X-ray photoelectron spectroscopy (HAXPES) for environmental samples such as radioactive microparticles collected around Fukushima Daiichi Nuclear Power Station, charge neutralization technique established using ion and electron coaxial irradiation. Using this technique, the chemical state analysis of the radioactive microparticles was realized.

Oral presentation

Chemical state of cesium in the insoluble radioactive particles emitted from Unit 1 of Fukushima Di-ichi Nuclear Power Station

Satou, Yukihiko; Kobata, Masaaki; Okane, Tetsuo; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Osaka, Masahiko; Owada, Kenji*; Sueki, Keisuke*; Ishii, Tatsuya*

no journal, , 

no abstracts in English

16 (Records 1-16 displayed on this page)
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