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Journal Articles

Shapiro steps in charge-density-wave states driven by ultrasound

Mori, Michiyasu; Maekawa, Sadamichi

Applied Physics Letters, 122(4), p.042202_1 - 042202_5, 2023/01

https://doi.org/10.1063/5.0132454
 Times Cited Count：3 Percentile：85.09(Physics, Applied)

Journal Articles

Magnon mode transition in real space

Iida, Kazuki*; Kodama, Katsuaki; Inamura, Yasuhiro; Nakamura, Mitsutaka; Chang, L.-J.*; Shamoto, Shinichi

Scientific Reports (Internet), 12, p.20663_1 - 20663_7, 2022/12

https://doi.org/10.1038/s41598-022-22555-9
 Times Cited Count：1 Percentile：28(Multidisciplinary Sciences)

Spin excitation of an ilmenite FeTiO$$_{3}$$ powder sample is measured by time-of-flight inelastic neutron scattering. The dynamic magnetic pair-density function $$D_{M}(r,E)$$ is obtained from the dynamic magnetic structure factor $$S_{M}(Q,E)$$ by the Fourier transformation.

Journal Articles

Measurement of density and viscosity for molten salts

Sato, Rika*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Hayashi, Hirokazu; Sugawara, Takanori; Nishihara, Kenji

Dai-43-Kai Nihon Netsu Bussei Shimpojiumu Koen Rombunshu (CD-ROM), 3 Pages, 2022/10

no abstracts in English

Journal Articles

Influence of pulse duration on mechanical properties and dislocation density of dry laser peened aluminum alloy using ultrashort pulsed laser-driven shock wave

Yoshida, Masayuki*; Nishihata, Itsuki*; Matsuda, Tomoki*; Ito, Yusuke*; Sugita, Naohiko*; Shiro, Ayumi*; Shobu, Takahisa; Arakawa, Kazuto*; Hirose, Akio*; Sano, Tomokazu*

Journal of Applied Physics, 132(7), p.075101_1 - 075101_9, 2022/08

https://doi.org/10.1063/5.0083511
 Times Cited Count：5 Percentile：67.2(Physics, Applied)

Journal Articles

Effect of sample density in prompt $$gamma$$-ray analysis

Maeda, Makoto; Segawa, Mariko; Toh, Yosuke; Endo, Shunsuke; Nakamura, Shoji; Kimura, Atsushi

Scientific Reports (Internet), 12(1), p.6287_1 - 6287_8, 2022/06

https://doi.org/10.1038/s41598-022-08594-2
 Times Cited Count：2 Percentile：31.9(Multidisciplinary Sciences)

Journal Articles

Fully chelating N$$_{3}$$O$$_{2}$$-pentadentate planar ligands designed for the strongest and selective capture of uranium from seawater

Mizumachi, Takumi*; Sato, Minami*; Kaneko, Masashi; Takeyama, Tomoyuki*; Tsushima, Satoru*; Takao, Koichiro*

Inorganic Chemistry, 61(16), p.6175 - 6181, 2022/04

https://doi.org/10.1021/acs.inorgchem.2c00306
 Times Cited Count：4 Percentile：36.89(Chemistry, Inorganic & Nuclear)

Based on unique 5-fold equatorial coordination of UO$$_{2}$$$$^{2+}$$, water-compatible pentadentate planar ligands, H$$_{2}$$saldian and its derivatives, were designed as strong and selective capture of UO$$_{2}$$$$^{2+}$$ in seawater. In the simulated seawater condition (0.5 M NaCl + 2.3 mM HCO$$_{3}$$$$^{-}$$/CO$$_{3}$$$$^{2-}$$, pH 8), saldian$$^{2-}$$ shows the strongest complexation with UO$$_{2}$$$$^{2+}$$ to form UO$$_{2}$$(saldian) (log$$beta$$$$_{11}$$ = 28.05 $$pm$$ 0.07), which is more than 10 order of magnitude greater than amidoxime-based or -inspired ligand systems most commonly employed for U capture from seawater. Good selectivity for UO$$_{2}$$$$^{2+}$$ from other metal ions coexisting in seawater was also demonstrated.

Journal Articles

Defect equilibria and thermophysical properties of CeO$$_{2-x}$$ based on experimental data and density functional theory calculation result

Watanabe, Masashi; Nakamura, Hiroki; Suzuki, Kiichi; Machida, Masahiko; Kato, Masato

Journal of the American Ceramic Society, 105(3), p.2248 - 2257, 2022/03

https://doi.org/10.1111/jace.18249
 Times Cited Count：1 Percentile：6.98(Materials Science, Ceramics)

Properties of CeO$$_{2}$$ were evaluated by DFT simulation to determine band gap, Frenkel defect formation energy and defect migration energy. Band gap and Frenkel defect formation energy were used to analyze defect equilibria. Oxygen partial pressure dependence of defect equilibria was evaluated based on oxygen potential experimental data and DFT calculation, and a Brouwer diagram was derived. The defect formation energies, including Frenkel defect, electron-hole pair and so on, were determined and used to evaluate the properties, including oxygen diffusion coefficients, electrical conduction, heat capacity and thermal conductivity. Mechanisms of various properties were discussed for a deeper understanding based on defect chemistry, and the relationship among properties were systematically described.

Journal Articles

Density functional study aiming to elucidate separation mechanisms of minor actinides and rare earths

Kaneko, Masashi

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 64(1), p.30 - 34, 2022/01

https://doi.org/10.3327/jaesjb.64.1_30

Partitioning of minor actinides from rare earths is one of the most important techniques to develop group separation of high-level radioactive liquid waste. In this issue, the results of prediction of separation performance between minor actinides and rare earths observed in solvent extraction and the separation mechanism by means of using density functional theory are explained.

JAEA Reports

Development of fundamental technologies for domestic production of medical radioisotope (technetium-99m); The First and second phase report (FY2014-2020)

Project 6 Meeting Members for Tsukuba International Strategic Zone

JAEA-Review 2021-016, 102 Pages, 2021/11

JAEA-Review-2021-016.pdf:12.76MB

In December 2011, the Prime Minister designated Tsukuba and some areas in Ibaraki Prefecture as "Comprehensive Special Zones". In the Tsukuba International Strategic Zone, nine advanced research and development (R&D) projects are underway with the goal of promoting industrialization of life innovation and green innovation utilizing the science and technology in Tsukuba. In these projects, the domestic production of medical radioisotope (Technetium-99m, $$^{rm 99m}$$Tc) was certified as a new project in October 2013, and R&D have been performed in collaboration with related organizations with Japan Atomic Energy Agency (JAEA) as the project leader. Japan is the third largest consumer of molybdenum-99 ($$^{99}$$Mo) after the United States and Europe, and all $$^{99}$$Mo are imported. Supply will be insufficient if overseas reactors are shut down due to trouble or if transportation (air and land transportations) is stopped due to volcanic eruptions and some accidents. Thus, early domestic production of $$^{99}$$Mo is strongly required. This project is a technology development aimed at domestic production of $$^{99}$$Mo, which is a raw material of $$^{rm 99m}$$Tc used as a diagnostic agent. This report summarizes the activities carried out in the first and second phase of the domestic production of medical radioisotope ($$^{rm 99m}$$Tc) (here referred to as the "Project 6") in Tsukuba International Strategic Zone (FY2014-2020).

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

https://doi.org/10.1246/cl.210402
 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

Density functional theory study on the $$^{193}$$Ir M$"o$ssbauer spectroscopic parameters of Vaska's complexes and their oxidative adducts

Kaneko, Masashi; Nakashima, Satoru*

Inorganic Chemistry, 60(17), p.12740 - 12752, 2021/09

https://doi.org/10.1021/acs.inorgchem.1c00239
 Times Cited Count：3 Percentile：32.49(Chemistry, Inorganic & Nuclear)

In the present study, density functional theory (DFT) calculation was applied to Vaska's complexes of formula ${it trans}$-[IrCl(CO)(PPh$$_{3}$$)$$_{2}$$], and their oxidative adducts with small molecules (YZ) including H$$_{2}$$, i.e., ${it trans}$-[IrCl(YZ)(CO))(PPh$$_{3}$$)$$_{2}$$], to successfully correlate the electronic states of the complexes with the corresponding $$^{193}$$Ir M$"o$ssbauer spectroscopic parameters. After confirming the reproducibility of the DFT methods for elucidating the equilibrium structures and $$^{193}$$Ir M$"o$ssbauer isomer shifts of the octahedral Ir complexes, the isomer shifts and quadrupole splitting values of Vaska's complexes and their oxidative adducts were calculated. A bond critical point analysis revealed that the tendency in the isomer shifts was correlated with the strength of the covalent interaction in the coordination bonds. In an electric field gradient (EFG) analysis of the oxidative adducts, the sign of the principal axis was found to be positive for the complex with YZ = Cl$$_{2}$$ and negative for the complex with YZ = H$$_{2}$$. This reversal of the sign of the EFG principal axis was caused by the difference in the electron density distribution for the coordination bonds between Ir and YZ, according to a density of states analysis.

Journal Articles

Density functional study on Am(III)/Eu(III) selectivity using crown ether type ligands

Fukasawa, Yuto*; Kaneko, Masashi; Nakashima, Satoru*

Journal of Radioanalytical and Nuclear Chemistry, 329(1), p.77 - 84, 2021/07

https://doi.org/10.1007/s10967-021-07685-0
 Times Cited Count：1 Percentile：16.35(Chemistry, Analytical)

Density functional theory calculations were applied to understand the selectivity between Am$$^{3+}$$ and Eu$$^{3+}$$ ions with the crown ethers type ligands. 18C6 is predicted to form the most stable complex with Eu$$^{3+}$$ and show the higher stability for Am$$^{3+}$$ over Eu$$^{3+}$$, being consistent with previously reported Am$$^{3+}$$/Eu$$^{3+}$$ selectivity. We modeled N- and S-donor complexes by using framework of 18C6 complex and analyzed the complexation Gibbs energies, indicating that 18C6 with N-donor atoms is suitable for both complexation and higher Am$$^{3+}$$ stability over Eu$$^{3+}$$ due to the stronger covalent interaction.

Journal Articles

Study on the free corrosion potential at an interface between an Al electrode and an acidic aqueous NaCl solution through density functional theory combined with the reference interaction site model

Kano, Koichi*; Hagiwara, Satoshi*; Igarashi, Takahiro; Otani, Minoru*

Electrochimica Acta, 377, p.138121_1 - 138121_10, 2021/05

AA2020-0599.pdf:0.95MB

https://doi.org/10.1016/j.electacta.2021.138121
 Times Cited Count：17 Percentile：71.29(Electrochemistry)

We investigated the free corrosion potential at an interface between an Al electrode and an aqueous NaCl solution under acidic conditions via density functional theory combined with the effective screening medium and reference interaction site model (ESM-RISM). The electrode potentials for the anodic and cathodic corrosion reactions were obtained from the grand potential profile as a function of the electron chemical potential at the interface. Thereafter, we determined the free corrosion potential using the Tafel extrapolation method. The results of the free corrosion potential were consistent with previous experimental data. By controlling the pH, we determined the pH dependence of the free corrosion potential, and the results agreed well with the experimental results. Our results indicated that the ESM-RISM method duly described the environmental effect of an acidic solution and precisely determined the free corrosion potential.

Journal Articles

Multiscale constitutive modeling of additively manufactured Al-Si-Mg alloys based on measured phase stresses and dislocation density

Zhang, X. X.*; Knoop, D.*; Andr$"a$, H.*; Harjo, S.; Kawasaki, Takuro; Lutz, A.*; Lahres, M.*

International Journal of Plasticity, 140, p.102972_1 - 102972_20, 2021/05

https://doi.org/10.1016/j.ijplas.2021.102972
 Times Cited Count：28 Percentile：94.45(Engineering, Mechanical)

Journal Articles

Density functional modeling of Am$$^{3+}$$/Eu$$^{3+}$$ selectivity with diethylenetriaminepentaacetic acid and its bisamide chelates.

Kaneko, Masashi; Sasaki, Yuji; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*

Journal of Nuclear Science and Technology, 58(5), p.515 - 526, 2021/05

https://doi.org/10.1080/00223131.2020.1842267
 Times Cited Count：3 Percentile：35.51(Nuclear Science & Technology)

Density-functional theory calculations were applied to molecular structure and complex formation reaction modelings of metal ion complexes with diethylenetriaminepentaacetic acid (DTPA) and its bisamide (DTPABA) chelates to understand the metal ions selectivity between Am$$^{3+}$$ and Eu$$^{3+}$$. The calculated complexes with DTPA and DTPABA chelates reproduced the coordination geometries of experimental crystal structures. Calculated Gibbs free energies of the complex formation reactions indicated that Am$$^{3+}$$ ion forms higher stable complexes with both chelates than Eu$$^{3+}$$ ion, being consistent with the experimental results. The higher Am$$^{3+}$$ selectivity over Eu$$^{3+}$$ was suggested to originate in the larger bond overlap between Am$$^{3+}$$ 5f-orbital and N 2s, 2p-orbital. This mean that the covalent contribution between metal ion and donor atoms differentiates the complex formation stabilities, leading to the Am$$^{3+}$$/Eu$$^{3+}$$ selectivity. We expect that this study contributes to systematize the origin of metal ions selectivity and to accelerate novel ligands exploration.

Journal Articles

Effect of oxygen-donor charge on adjacent nitrogen-donor interactions in Eu$$^{3+}$$ complexes of mixed N,O-donor ligands demonstrated on a 10-fold [Eu(TPAMEN)]$$^{3+}$$ chelate complex

Schnaars, K.; Kaneko, Masashi; Fujisawa, Kiyoshi*

Inorganic Chemistry, 60(4), p.2477 - 2491, 2021/02

https://doi.org/10.1021/acs.inorgchem.0c03405
 Times Cited Count：6 Percentile：59.03(Chemistry, Inorganic & Nuclear)

To reduce high-level radiotoxic waste generated by nuclear power plants, highly selective separation agents for minor actinides are mandatory. The mixed N,O-donor ligand ${it N,N,N',N'}$-tetrakis[(6-carboxypyridin-2-yl)methyl]ethylenediamine (H$$_{4}$$TPAEN) has shown good performance as a masking agent in Am$$^{3+}$$/Eu$$^{3+}$$ separation studies. In this work, we examine whether a decrease in O-donor basicity can promote the M$$^{3+}$$-N$$_{am}$$ interactions. Therefore, we replace the deprotonated "charged" carboxylic acid groups of TPAEN$$^{4-}$$ by neutral amide groups and introduce ${it N,N,N',N'}$-tetrakis[(6-${it N",N"}$-diethylcarbamoylpyridin-2-yl)methyl]ethylenediamine (TPAMEN) as a new ligand. TPAMEN was crystallized with Eu(OTf)$$_{3}$$ and Eu(NO$$_{3}$$)$$_{3}$$ 6H$$_{2}$$O to form positively charged 1:1 [Eu(TPAMEN)]$$^{3+}$$ complexes in the solid state. Alterations in the M-O/N bond distances are compared to [Eu(TPAEN)]$$^{-}$$ and investigated by DFT calculations to expose the differences in charge/energy density distributions at europium(III) and the donor functionalities of the TPAEN$$^{4-}$$ and TPAMEN. On the basis of estimations of the bond orders, atomic charges spin populations, and density of states in the Eu and potential Am and Cm complexes, the specific contributions of the donor-metal interaction are analyzed. The prediction of complex formation energy differences for the [M(TPAEN)]$$^{-}$$ and [M(TPAMEN)]$$^{3+}$$ (M$$^{3+}$$ = Eu$$^{3+}$$, Am$$^{3+}$$) complexes provide an outlook on the potential performance of TPAMEN in Am$$^{3+}$$/Eu$$^{3+}$$ separation.

JAEA Reports

Impact assessment of density change on the buffer material on the coupled thermal-hydraulic and mechanical (THM) behavior in the near-field (Contract research)

Suzuki, Hideaki*; Takayama, Yusuke

JAEA-Research 2020-015, 52 Pages, 2020/12

JAEA-Research-2020-015.pdf:3.83MB

It is anticipated that the coupled thermal hydraulic and mechanical (THM) processes will occur, involving an interactive process with radioactive decay heat arising from the vitrified waste, infiltration of groundwater from the host rock into the buffer material, swelling pressure of buffer material due to its saturation in the near-field of a geological disposal system for high-level radioactive waste repository. In order to evaluate these phenomena in the near-field, the THM model has been developed. In this report, the density dependence of thermal, hydraulic and mechanical properties of the buffer material was investigated to evaluate the near-field environment. These density dependence schemes were added to the coupled THM model. The THM analysis of the in-situ experiment of engineered barrier system (EBS) experiment at the Horonobe Underground Research Laboratory was carried out. As a result, the effect of the density change of the buffer material on the temperature and infiltration behavior of buffer material was found. A case analysis on the long-term behavior of the near field was also carried out. Then, the behavior that the buffer material swelled out toward the backfill material and the density of the buffer material decreasing was shown.

Journal Articles

Complexation and bonding studies on [Ru(NO)(H$$_{2}$$O)$$_{5}$$]$$^{3+}$$ with nitrate ions by using density functional theory calculation

Kato, Akane*; Kaneko, Masashi; Nakashima, Satoru*

RSC Advances (Internet), 10(41), p.24434 - 24443, 2020/06

https://doi.org/10.1039/D0RA05042C
 Times Cited Count：6 Percentile：31.74(Chemistry, Multidisciplinary)

Complexation reactions of ruthenium-nitrosyl complexes in HNO$$_{3}$$ solution were investigated by density functional theory (DFT) calculations in order to predict the stability of Ru species in high-level radioactive liquid waste (HLLW) solution. Equilibrium structure of [Ru(NO)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)$$_{2}$$] obtained by DFT calculations reproduced the experimental Ru-ligands bond lengths and IR frequencies reported previously. Comparison of the Gibbs energies among the geometrical isomers revealed that the complexation reactions of the ruthenium-nitrosyl complexes with NO$$_{3}$$$$^{-}$$ proceed via the NO$$_{3}$$$$^{-}$$ coordination to the equatorial plane toward the Ru-NO axis. We also estimated Gibbs energy differences on the stepwise complexation reactions to succeed in reproducing the fraction of Ru-NO species in 6 M HNO$$_{3}$$ solution, such as in HLLW, by considering the association energy between the Ru-NO species and the substituting ligands. Electron density analyses of the complexes indicated that the strength of the Ru-ligands coordination bonds depends on the stability of the Ru species and the Ru complex without NO$$_{3}$$$$^{-}$$ at the axial position is more stable than that wit NO$$_{3}$$$$^{-}$$, which might attribute to the difference in the trans influence between H$$_{2}$$O and NO$$_{3}$$$$^{-}$$. Finally, we demonstrated the complexation kinetics in the reactions $$x = 1 rightarrow x = 2$$. The present study is expected to enable us to model the precise complexation reactions of platinum-group metals in HNO$$_{3}$$ solution.

Journal Articles

Comparison of dislocation density, twin fault probability, and stacking fault energy between CrCoNi and CrCoNiFe medium entropy alloys deformed at 293 and 140K

Woo, W.*; Naeem, M.*; Jeong, J.-S.*; Lee, C.-M.*; Harjo, S.; Kawasaki, Takuro; He, H.*; Wang, X.-L.*

Materials Science & Engineering A, 781, p.139224_1 - 139224_7, 2020/04

https://doi.org/10.1016/j.msea.2020.139224
 Times Cited Count：39 Percentile：93.57(Nanoscience & Nanotechnology)

Journal Articles

Characterization of microstructures by X-ray diffraction line profile analysis, 2; Line profile analysis using synchrotron radiation

Shobu, Takahisa; Shiro, Ayumi*; Yoshida, Yutaka*

Zairyo, 69(4), p.343 - 347, 2020/04

https://doi.org/10.2472/jsms.69.343

Dislocation density is a very important physical quantity in the evaluation of fatigue of metallic materials. Generally, the dislocation density is evaluated by a scanning electron microscope. Recently, a method generated the dislocation density from the width of the X-ray diffraction profile has been proposed. In this study, we report the application of this technology to synchrotron radiation. Five diffraction profiles were obtained with a two-dimensional detector during tensile loading of the austenitic stainless steel SUS316L, and the dislocation density was calculated from the line profile analysis. As a result, the dislocation density increased sharply after plastic deformation, and the value was in good agreement with the result separately measured with a scanning electron microscope. In the future, it is expected that the line profile analysis will contribute to the elucidation of the mechanism of fatigue fracture by measuring the dislocation density from the local area in materials.

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