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Journal Articles

Physics of spin-triplet superconductivity in uranium compounds studied by NMR

Tokunaga, Yo; Sakai, Hironori; Kitagawa, Shunsaku*; Ishida, Kenji*

Nihon Butsuri Gakkai-Shi, 78(5), p.267 - 272, 2023/04

no abstracts in English

Journal Articles

Extreme chemistry of superheavy elements

Sato, Tetsuya; Nagame, Yuichiro*

Nihon Butsuri Gakkai-Shi, 78(2), p.64 - 72, 2023/02

The study of the chemistry of superheavy elements, which are located in the heavy extremes of the periodic table, has made considerable progress over the past 20 years, and new approaches based on various ideas have recently been developed. Research groups in Japan have also made significant contributions to the development of research on superheavy elements. Recently, notable results have been reported for the transactinide elements rutherfordium (element 104), dubnium (element 105), and seaborgium (element 106), and the heavy actinides with atomic numbers exceeding 100. The review will focus on the recent main results of these elements. This review outlines the main recent results and touches on future prospects.

Journal Articles

Atomtronics

Uchino, Shun

Nihon Butsuri Gakkai-Shi, 76(1), p.4 - 12, 2021/01

Ultracold atomic gases allow us to simulate bare essentials of complicated quantum phenomena. Recently, atomtronics devices to simulate mesoscopic transport with ultracold atomics gases have been realized in experiments. In this article, we review recent progress of two-terminal transport in ultracold atomic gases, with a special focus on point contact transport in two-component Fermi gases.

Journal Articles

Ultrafast carrier dynamics and light-induced functionalizations of topological insulators

Sumida, Kazuki; Ishida, Yukiaki*; Kimura, Akio*

Nihon Butsuri Gakkai-Shi, 75(12), p.756 - 760, 2020/12

Journal Articles

Skyrmion; 60 years of evolution

Oka, Makoto

Nihon Butsuri Gakkai-Shi, 75(10), p.608 - 609, 2020/10

An introductory review of the Skyrmion in the JPS bulletin journal.

Journal Articles

Origin of the dramatic change of fission mode in fermium isotope investigated using Langevin equations

Aritomo, Yoshihiro*; Miyamoto, Yuya*; Nishio, Katsuhisa

Nihon Butsuri Gakkai-Shi, 75(10), p.631 - 636, 2020/10

no abstracts in English

Journal Articles

Diffusion mechanisms of hydrogen in metals explored via path-integral methods

Kimizuka, Hajime*; Ogata, Shigenobu*; Shiga, Motoyuki

Nihon Butsuri Gakkai-Shi, 75(8), p.484 - 490, 2020/08

Hydrogen is an element having quantum nature, and exhibits a unique diffusion behavior not found in other impurity atoms. In this study, the diffusion behavior of hydrogen isotopes in palladium crystals was predicted at a wide range of temperatures using a first-principles approach that combines the path integral simulation and electronic structure calculation. It was shown that in the high temperature region, the influence of quantum fluctuations becomes apparent as the temperature decreases, causing the suppression of diffusion where the Arrhenius plot bends upward. On the other hand, in the low temperature region, the diffusion barrier decreases due to the manifestation of the quantum tunneling effect, and the Arrhenius plot bents downward. The competition of quantum effects in different temperature regions clearly explains the anomalous isotopic effect of hydrogen diffusion.

Journal Articles

High-energy atmospheric phenomena initiated by lightning

Enoto, Teruaki*; Wada, Yuki*; Tsuchiya, Harufumi

Nihon Butsuri Gakkai-Shi, 74(4), p.192 - 200, 2019/04

no abstracts in English

Journal Articles

Mottled electronic state near a quantum critical phase transition

Kambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo

Nihon Butsuri Gakkai-Shi, 71(1), p.22 - 26, 2016/01

By means of nuclear magnetic resonance (NMR) spin-lattice relaxation time measurements on a single crystal YbRh$$_2$$Si$$_2$$ sample, it is revealed that the coexisting Fermi and non-Fermi states appears near the quantum critical phase transition. Such a mottled state has remained hidden in Ce and U heavy fermion compounds, owing presumably to short lifetimes for the two states. Valence and magnetic instabilities are considered to occur at the same time around the quantum critical phase transition.

Journal Articles

Discovery of new magic number ${it via}$ in-beam $$gamma$$-ray spectroscopy

Takeuchi, Satoshi*; Steppenbeck, D.*; Utsuno, Yutaka

Nihon Butsuri Gakkai-Shi, 70(7), p.535 - 539, 2015/07

no abstracts in English

Journal Articles

Generation of medical radioisotopes using accelerator neutrons

Nagai, Yasuki; Hashimoto, Kazuyuki

Nihon Butsuri Gakkai-Shi, 69(6), p.370 - 375, 2014/06

In Japan, about 0.9 million diagnostic procedures are carried out using $$^{rm 99m}$$Tc, the daughter nuclide of $$^{99}$$Mo with a half-life of 66 h, separated from $$^{99}$$Mo; all $$^{99}$$Mo radioisotopes are imported. Most of $$^{99}$$Mo has been produced by the fission reaction of highly enriched $$^{235}$$U in research reactors in the world. However, a number of incidents of the reactors caused the shortage of $$^{99}$$Mo worldwide, which triggered widespread discussions on the reliable supply of $$^{99}$$Mo. We proposed a new route to produce a large quantity of high quality $$^{99}$$Mo using fast neutrons from an accelerator.

Journal Articles

First-principles calculation to explore mechanisms of coherent phonon generation

Shinohara, Yasushi*; Otobe, Tomohito; Iwata, Junichi*; Yabana, Kazuhiro*

Nihon Butsuri Gakkai-Shi, 67(10), p.685 - 689, 2012/10

Coherent phonon is the macroscopic coherent oscillation of atoms in a solid state generating under the ultrafast laser pulse which is shorter than the frequency of the phonon. Some physical processes for the coherent phonon have been proposed. We are studying the computational method describing the dynamics of the electron and atom employing the time-dependent density functional theory. Our computational results show the origine of the coherent phonon in Si quantitatively.

Journal Articles

Nucleosynthesis in supernovae and neutrino oscillation

Suzuki, Toshio*; Yoshida, Takashi*; Chiba, Satoshi; Kajino, Toshitaka*

Nihon Butsuri Gakkai-Shi, 67(1), p.49 - 54, 2012/01

Neutrino processes play important roles in synthesis of $$^7$$Li, $$^{11}$$B, $$^{138}$$La, $$^{180}$$Ta and other elements in explosive environments realized in supernovae. In order to understand better the neutrino processes, we constructed new shell model Hamiltonians based on recent progress of physics in unstable nuclei near the neutron drip-line. We then applied these Hamiltonians to calculate the neutrino-nucleus reaction cross sections through detailed and careful comparison of nuclear properties with those of relevant experimental data. We can thus carry out precise and reliable theoretical estimate of supernova nucleosynthesis of $$^{7}$$Li, $$^{11}$$B, etc including the neutrino processes. Finally we propose a new method to determine unknown neutrino oscillation parameters, namely the mixing angle $$theta_{13}$$ and the mass hierarchy, by making use of strong dependence of the yields of $$^{7}$$Li, $$^{11}$$B on these parameters.

Journal Articles

Nucleosynthesis in supernovae and neutrino oscillation

Suzuki, Toshio*; Yoshida, Takashi*; Chiba, Satoshi; Kajino, Toshitaka*

Nihon Butsuri Gakkai-Shi, 67(1), p.49 - 54, 2012/01

Neutrino-nucleus reaction processes play important roles in synthesis of $$^7$$Li, $$^{11}$$B, $$^{138}$$La, $$^{180}$$Ta and other elements in explosive environments realized in supernovae. We have constructed new shell model Hamiltonians based on recent progress of physics in unstable nuclei near the neutron drip-line. The spin responses of nuclei are found to be remarkably improved by the new Hamiltonians. We then applied these Hamiltonians to calculate the neutrino-nucleus reaction cross sections, and obtained more precise and reliable theoretical estimate of supernova nucleosynthesis of $$^7$$Li, $$^{11}$$B, etc including the neutrino processes. Finally we propose a new method to determine unknown neutrino oscillation parameters, namely the mixing angle $$theta_{13}$$ and the mass hierarchy, by making use of strong dependence of the yields of $$^7$$Li and $$^{11}$$B on these parameters.

Journal Articles

Journal Articles

From GMR to TMR

Maekawa, Sadamichi; Ieda, Junichi

Nihon Butsuri Gakkai-Shi, 65(5), p.324 - 330, 2010/05

A multilayer alternately stacked with several atomic layers of a ferromagnetic metal and those of a normal metal shows a drastic decrease in its electrical resistance in an applied magnetic field. This discovery in 1988, the giant magnetoresistance (GMR), has developed a new nanotechnology, the so-called spin-electronics (spintronics), offering a variety of issues which involve in magnetism and electrical conduction. Tunnel magnetoresistance (TMR) observed in a tunnel junction, which sandwiches in a few atomic layers of an insulator between ferromagnetic metals, attracts much attention these days both in fundamental and applied levels. Currently this stream leads to understandings of physical phenomena emerging from interactions between charge current and spin current in nanoscale materials.

Journal Articles

Diffusion experiment with the accelerated, shorot-lived radioactive beam of $$^{8}$$Li

Jeong, S.-C.*; Sugai, Hiroyuki; Yahagi, Masahito*

Nihon Butsuri Gakkai-Shi, 64(9), p.687 - 691, 2009/09

We have demonstrated a non-destructive and on-line radiotracer method for diffusion studies in lithium ionic conductors, by using, as a tracer, the short-lived alpha-emitting radioisotope of $$^{8}$$Li from TRIAC (Tokai Radioactive Ion Accelerator Complex). The method has been successfully applied to measure the lithium diffusion coefficients in a typical defect-mediated lithium ionic conductor of LiGa, well demonstrating that the method is very effective to measure the diffusion in the micrometer regime per second. Anomalous composition-dependence of Li diffusion coefficients in LiGa was observed. The anomaly was discussed qualitatively in terms of the formation of defect complex and the interaction between the constituent defects. The ordering of the Li vacancies in the Li-deficient LiGa was observed for the first time in terms of the Li diffusion by the present method, and its thermodynamic aspect was discussed.

Journal Articles

Present status and future subjects of first-principles-based simulations for chemical reactions

Ikeda, Takashi; Boero, M.*; Morikawa, Yoshitada*

Nihon Butsuri Gakkai-Shi, 64(4), p.256 - 262, 2009/04

First-principles-based simulations not relying on any empirical parameters are nowadays applicable to elucidate elemental processes of various chemical reactions occurring in condensed phase as well as in gas phase. In this article, the present status of the reactive simulations for surface, interface and biological systems is reviewed as examples and their future subjects are also summarized.

Journal Articles

Utilization of radiation in industrial, agricultural and medical fields and its perspective

Shibata, Tokushi

Nihon Butsuri Gakkai-Shi, 63(4), p.257 - 264, 2008/04

The current status for the utilization of radiation in Japan was given from the view point of the economic scale. The topics which will be developed in near future such as lithography, radiation processing, radiation analysis in the industry, mutation breeding, sterile insect technique, food irradiation in agriculture, and radiation diagnosis, radiation therapy in medical field were presented. The important techniques for the further development of utilization of radiation will be the techniques related to the fabrication of semiconductor, developments of small accelerators and compact neutron generators.

Journal Articles

Heavy fermion superconductivity in the transuranium neptunium compound

Aoki, Dai*; Haga, Yoshinori; Onuki, Yoshichika

Nihon Butsuri Gakkai-Shi, 63(2), p.129 - 132, 2008/02

Several unconventional superconductors with non-s wave symmetry are known in the rare earth and uranium compounds with f-electrons. However, no superconductivity has been reported in the transuranium neptunium compounds in the past. Here we report the first observation of the superconductivity in the new compound NpPd$$_5$$Al$$_2$$. Novel superconducting phenomena, such as high superconducting transition temperature, strong paramagnetic effect and first-order phase transition at the upper critical field, were found in NpPd$$_5$$Al$$_2$$.

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