Existence of local polar domains in perovskite oxyfluoride, BaFeOF

Katsumata, Tetsuhiro*; Suzuki, Ryo*; Sato, Naoto*; Oda, Ryoya*; Motoyama, Shingo*; Suzuki, Shumpei*; Nakashima, Mamoru*; Inaguma, Yoshiyuki*; Mori, Daisuke*; Aimi, Akihisa*; et al.

Chemistry of Materials, 36(8), p.3697 - 3704, 2024/04

https://doi.org/10.1021/acs.chemmater.3c03275

A perovskite-type oxynitride BaFeOF was prepared by high-pressure synthesis. Since the SHG signal was observed in the obtained material, suggesting the existence of spontaneous polarization, the mechanism of polarization was investigated by synchrotron high-energy X-ray diffraction. The obtained pair distribution functions were fitted, and a local polarization mechanism with different orientations was found. Since BaFeOF is also a magnetic material, a magnetic domain and a ferroelectric domain are considered to coexist.

Dynamic interaction between dislocations and obstacles in BCC iron based on atomic potentials derived using neural networks

Mori, Hideki*; Tsuru, Tomohito; Okumura, Masahiko; Matsunaka, Daisuke*; Shiihara, Yoshinori*; Itakura, Mitsuhiro

Physical Review Materials (Internet), 7(6), p.063605_1 - 063605_8, 2023/06

https://doi.org/10.1103/PhysRevMaterials.7.063605

The introduction of obstacles (e.g., precipitates) for controlling dislocation motion in molecular structures is a prevalent method for designing the mechanical strength of metals. Owing to the nanoscale size of the dislocation core ( 1 nm), atomic modeling is required to investigate the interactions between the dislocation and obstacles. However, conventional empirical potentials are not adequately accurate, in contrast to the calculations based on density functional theory (DFT). Therefore, the atomic-level details of the interactions between the dislocations and obstacles remain unclarified. To this end, this study applied an artificial neural network (ANN) framework to construct an atomic potential by leveraging the high accuracy of DFT. Using the constructed ANN potential, we investigated the dynamic interaction between the edge dislocation and obstacles in BCC iron. When the dislocation crossed the void, an ultrasmooth and symmetric half-loop was observed for the bowing-out dislocation. Except for the screw dislocation, the Peierls stress of all the dislocations predicted using the ANN was less than 100 MPa. More importantly, the results confirmed the formation of an Orowan loop in the interaction between a rigid sphere and dislocation. Furthermore, we discovered a phenomenon in which the Orowan loop disintegrated into two small loops during its interaction with the rigid sphere and dislocation.

High-spin states in S

Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.

Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03

https://doi.org/10.1103/PhysRevC.103.034327

How different is the core of F from O ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

https://doi.org/10.1103/PhysRevLett.124.212502

The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Synthesis of new perovskite-type oxyfluorides, BaInOF and comparison of the structure among perovskite-type oxyfluorides

Katsumata, Tetsuhiro*; Suzuki, Ryo*; Sato, Naoto*; Suzuki, Shumpei*; Nakashima, Mamoru*; Inaguma, Yoshiyuki*; Mori, Daisuke*; Aimi, Akihisa*; Yoneda, Yasuhiro

Journal of Solid State Chemistry, 279, p.120919_1 - 120919_8, 2019/11

https://doi.org/10.1016/j.jssc.2019.120919

Extraction behavior of Mo and W from HSO and HF/HCl solutions into toluene with Aliquat336; Sulfate and fluoride complex formation of Mo and W towards chemical studies of seaborgium (Sg)

Toyoshima, Atsushi; Mitsukai, Akina; Tsukada, Kazuaki; Oe, Kazuhiro*; Haba, Hiromitsu*; Komori, Yukiko*; Murakami, Masashi; Kaneya, Yusuke*; Sato, Daisuke*; Asai, Masato; et al.

Journal of Radioanalytical and Nuclear Chemistry, 317(1), p.421 - 430, 2018/07

https://doi.org/10.1007/s10967-018-5882-5

We have studied extraction behavior of group-6 elements Mo and W to search for suitable conditions for an on-line extraction experiment of their heavier homolog, seaborgium (Sg). Batch-wise extraction of carrier-free radiotracers Mo and W were carried out from 0.10 - 8.6 M HSO and 1.010 - 5.0 M HF/1.0 M HCl into toluene with a quaternary ammonium compound, Aliquat336. Anionic sulfate complexes of Mo and W with charge - 2 were extracted with Aliquat336 from HSO solutions with concentrations of [HSO] 2 M. In HF/1.0 M HCl, oxyfluoro complexes of Mo and W with charge - 1 were interpreted to be formed and extracted with Aliquat336. From these results, favorable conditions for the extraction of Sg are discussed.

ROSA/LSTF tests and RELAP5 posttest analyses for PWR safety system using steam generator secondary-side depressurization against effects of release of nitrogen gas dissolved in accumulator water

Takeda, Takeshi; Onuki, Akira*; Kanamori, Daisuke*; Otsu, Iwao

Science and Technology of Nuclear Installations, 2016, p.7481793_1 - 7481793_15, 2016/00

AA2016-0048.pdf:5.15MB

https://doi.org/10.1155/2016/7481793

TRAIL-R2 superoligomerization induced by human monoclonal agonistic antibody KMTR2

Tamada, Taro; Shinmi, Daisuke*; Ikeda, Masahiro*; Yonezawa, Yasushi*; Kataoka, Shiro*; Kuroki, Ryota; Mori, Eiji*; Motoki, Kazuhiro*

Scientific Reports (Internet), 5, p.17936_1 - 17936_12, 2015/12

https://doi.org/10.1038/srep17936

The fully human monoclonal antibody KMTR2 acts as a strong direct agonist for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2 (TRAIL-R2), which is capable of inducing apoptotic cell death without cross-linking. To investigate the mechanism of direct agonistic activity induced by KMTR2, the crystal structure of the extracellular region of TRAIL-R2 and a Fab fragment derived from KMTR2 (KMTR2-Fab) was determined to 2.1 resolution. Two KMTR2-Fabs assembled with the complementarity-determining region 2 of the light chain via two-fold crystallographic symmetry, suggesting that the KMTR2-Fab assembly tended to enhance TRAIL-R2 oligomerization. A single mutation at Asn53 to Arg located at the two-fold interface in the KMTR2 resulted in a loss of its apoptotic activity, although it retained its antigen-binding activity. These results indicate that the strong agonistic activity, such as apoptotic signaling and tumor regression, induced by KMTR2 is attributed to TRAIL-R2 superoligomerization induced by the interdimerization of KMTR2.

Experiments of coolant accumulation in SG U tube and analytical model development

Yamaji, Tatsuya*; Koizumi, Yasuo; Yamazaki, Kohei*; Otake, Hiroyasu*; Hasegawa, Koji*; Onuki, Akira*; Kanamori, Daisuke*

Konsoryu Shimpojiumu 2015 Koen Rombunshu (USB Flash Drive), 2 Pages, 2015/08

Experiments of condensing counter-current two-phase flow in a vertical pipe were performed. This study was intended to examine water accumulation in the up-flow side of steam generator U-tubes of a PWR during the reflux cooling stage of a small break LOCA. It has been apprehended that the water accumulation may result in temporary core liquid level depression. The inner diameter and the length of a test flow channel used in the experiments were 18 mm and 4 m, respectively. The experiments were performed by using steam and water at 0.1 MPa. Two kinds of experiments were conducted; visualization experiments by using a transparent test section and quantitative water accumulation evaluation experiments by using a brass test section. Even if water on the inner surface of the test pipe could not flow downward at the lower portion of the test pipe, a part of water became to flow downward at the upper portion of the test pipe since steam velocity decreased because of condensation. Thus, two-phase mixture level was formed in the upper portion of the test pipe, which resulted in the water accumulation in the pipe. The model to predict the water accumulation was proposed. It predicted the water accumulation reasonably well.

Precise determination of C level structure by -ray spectroscopy

Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08

https://doi.org/10.1093/ptep/ptv113

Level structure of the C hypernucleus was precisely determined by means of -ray spectroscopy. We identified four -ray transitions via the C reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet was measured to be (stat) (syst)keV from the direct transition. Excitation energies of the and states were measured to be , keV and , keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of hypernuclei.