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Kusaka, Ryoji
Bunko Kenkyu, 72(4), p.155 - 162, 2023/08
Vibrational sum frequency generation (VSFG) spectroscopy is an optical second-order nonlinear vibrational spectroscopy using ultrashort pulse lasers. Because VSFG spectroscopy is a unique and powerful tool for studying molecular structures of interfaces, it has been widely used in many research fields. However, there still undoubtedly remains some VSFG research areas that have not studied well, partly because VSFG measurements are not so easily performed in comparison with relatively general spectroscopy methods. This review presented recent applications of VSFG spectroscopy to two research topics: (1) chemical reactions on water surfaces, and (2) actinide chemistry.
Nakayama, Katsumasa*; Suzuki, Kei
Physics Letters B, 843, p.138017_1 - 138017_7, 2023/08
Times Cited Count:0 Percentile:0.02(Astronomy & Astrophysics)The Casimir effect is a quantum phenomenon induced by the zero-point energy of relativistic fields confined in a finite-size system. This effect for photon fields has been studied for a long time, while the realization of counterparts for fermion fields in Dirac/Weyl semimetals is an open question. We theoretically demonstrate the typical properties of the Casimir effect for relativistic electron fields in Dirac/Weyl semimetals and show the results from an effective Hamiltonian for realistic materials such as CdAs and NaBi. We find an oscillation of the Casimir energy as a function of the thickness of the thin film, which stems from the existence of Dirac/Weyl nodes in momentum space. Experimentally, such an effect can be observed in thin films of semimetals, where the thickness dependence of thermodynamic quantities is affected by the Casimir energy.
Tamatsukuri, Hiromu; Hasegawa, Takumi*; Sagayama, Hajime*; Mizumaki, Masaichiro*; Murakami, Yoichi*; Kajitani, Joe*; Higashinaka, Ryuji*; Matsuda, Tatsuma*; Aoki, Yuji*; Tsutsui, Satoshi*
Physical Review B, 107(2), p.024303_1 - 024303_8, 2023/01
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)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
Kusaka, Ryoji; Watanabe, Masayuki
Journal of Physical Chemistry Letters (Internet), 13(30), p.7065 - 7071, 2022/08
Times Cited Count:5 Percentile:70.33(Chemistry, Physical)Funato, Takumi*; Matsuo, Mamoru
Physical Review Letters, 128(7), p.077201_1 - 077201_6, 2022/02
Times Cited Count:3 Percentile:58.88(Physics, Multidisciplinary)Takamura, Hiroaki*; Hamada, Hajime*; Sato, Toshinori
Dai-48-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (Internet), p.13 - 18, 2022/01
In the stage blasting of a mountain tunnel, the condition of single hole initiation in which the effect of other stage does not enter was made by increasing the interval of initiation time between front and rear stages using an electron detonator, and the waveform of vibration and sound pressure at that time was measured. The knowledge obtained from the analysis of sound pressure waveform of single hole blasting is considered to be effective to be utilized for the examination of sound pressure reduction effect of controlled blasting and the analysis of error of noise prediction formula.
Kusaka, Ryoji; Watanabe, Masayuki
Journal of Physical Chemistry B, 125(24), p.6727 - 6731, 2021/06
Times Cited Count:8 Percentile:44.55(Chemistry, Physical)Kusaka, Ryoji
Journal of Nuclear and Radiochemical Sciences (Internet), 20, p.28 - 31, 2020/06
Kofu, Maiko; Yamamuro, Osamu*
Journal of the Physical Society of Japan, 89(5), p.051002_1 - 051002_12, 2020/05
Times Cited Count:3 Percentile:31.18(Physics, Multidisciplinary)The behavior of hydrogen in metals has attracted much attention in fundamental and applied research areas for many decades. Among metals, palladium is remarkable in that it can absorb large quantities of hydrogen, and hydrogen atoms are highly mobile in the fcc Pd lattice. The dynamics of hydrogen in Pd have been investigated by means of neutron spectroscopy which is the best tool to provide insights into microscopic dynamics of hydrogen atoms. In this article, we review recent and historical neutron scattering works to facilitate the latest understanding of the hydrogen dynamics in bulk and nanometer-sized Pd hydrides.
Kusaka, Ryoji
Hosha Kagaku, (41), p.31 - 33, 2020/03
This commentary article introduced researches involved in encouragement award 2019 of the Japan Society of Nuclear and Radiochemical Sciences. Vibrational sum frequency generation (VSFG) spectroscopy and interfacial studies of solvent extraction of lanthanides and actinides using VSFG spectroscopy were described.
Kurosaki, Yuzuru*; Yokoyama, Keiichi
Universe (Internet), 5(5), p.109_1 - 109_15, 2019/05
Times Cited Count:0 Percentile:0.01(Astronomy & Astrophysics)Regarding rovibrational transitions of diatomic alkali haride molecules, optimal waveform of laser electric field was calculated on the basis of the optimal control theory. In this study, we implemented the polarizability term into the Hamiltonian, which defines the field-molecule interaction. As a result, we obtained waveforms causing both one- and two-photon processes in a relatively high electric field regime, while waveforms causing only one-photon process was observed in a weak filed regime as well as the previous study. These results imply that the effect of two-photon process is successfully taken into account in the optimal control theory calculation. Now we can expect more reliable calculation even for strong laser field.
Kusaka, Ryoji; Watanabe, Masayuki
Physical Chemistry Chemical Physics, 20(47), p.29588 - 29590, 2018/12
Times Cited Count:18 Percentile:70.02(Chemistry, Physical)Mechanistic understanding of solvent extraction of uranyl ions (UO) by tributyl phosphate (TBP) will help improve the technology for the treatment and disposal of spent nuclear fuels. So far, it has been believed that uranyl ions in the aqueous phase are adsorbed to a TBP-enriched organic/aqueous interface, form complexes with TBP at the interface, and are extracted into the organic phase. Here we show that uranyl-TBP complex formation does not take place at the interface using vibrational sum frequency generation (VSFG) spectroscopy and propose an alternative extraction mechanism that uranyl nitrate, UO(NO), passes through the interface and forms the uranyl-TBP complex, UO(NO)(TBP), in the organic phase.
Kofu, Maiko; Faraone, A.*; Tyagi, M.*; Nagao, Michihiro*; Yamamuro, Osamu*
Physical Review E, 98(4), p.042601_1 - 042601_6, 2018/10
Times Cited Count:4 Percentile:36.54(Physics, Fluids & Plasmas)Shibata, Takanori*; Shinto, Katsuhiro; Takagi, Akira*; Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Nammo, Kesao*; Naito, Fujio*
AIP Conference Proceedings 2011, p.020008_1 - 020008_3, 2018/09
Times Cited Count:5 Percentile:91.75(Physics, Applied)Nakata, Hisakazu; Hayashi, Hirokazu; Amazawa, Hiroya; Sakai, Akihiro
JAEA-Technology 2017-031, 41 Pages, 2018/01
JAEA plans to install disposal facilities for radioactive waste arising from research institutes. It must meet the technical standards specified in the relevant rule. One technical standard is that the disposal facilities shall be performance so as not to be left with the voids after the backfilling with soil. Additionally, the rule also requires this radioactive waste be enclosed in a container in which no harmful voids remain. In order to contribute to the development of a method that adapts the disposal facilities to these technical standards, JAEA adopts a waste conditioning artifice that aims for reducing a quantity of voidage in each waste container by a vibration filling method using sandy soil, providing with average void ratios inside the disposal facilities being adequately controlled. In this reports, filling property tests are conducted in the light of filling sand characteristics, types of metal waste and vibration conditions.
Matsumoto, Takahiro*; Ohara, Takashi; Sugimoto, Hidehiko*; Bennington, S. M.*; Ikeda, Susumu*
Physical Review Materials (Internet), 1(5), p.051601_1 - 051601_6, 2017/10
Times Cited Count:2 Percentile:7.76(Materials Science, Multidisciplinary)Kofu, Maiko; Hashimoto, Naoki*; Akiba, Hiroshi*; Kobayashi, Hirokazu*; Kitagawa, Hiroshi*; Iida, Kazuki*; Nakamura, Mitsutaka; Yamamuro, Osamu*
Physical Review B, 96(5), p.054304_1 - 054304_7, 2017/08
Times Cited Count:15 Percentile:58.3(Materials Science, Multidisciplinary)The vibrational states of hydrogen atoms in bulk and nanocrystalline palladium were examined in a wide energy region meV using neutron spectroscopy. In bulk PdH, the vibrational excitations of H atoms were roughly reproduced by the quantum harmonic oscillator (QHO) model. In PdH nanocrystals with a diameter of 8 nm, however, additional vibrational excitations were found at energies above 80 meV. The energies and intensities of the additional states were not explained by QHO but reasonably described as vibrations in a highly anharmonic trumpet-like potential. The additional excitations are attributed to the vibrations of H atoms at tetrahedral sites in the subsurface region stabilized by surface effects. This is an experimental work which clearly detects hydrogen vibration metal nanoparticles.
Yamano, Hidemasa; Tanaka, Masaaki; Ebara, Shinji*; Hashizume, Hidetoshi*
Proceedings of 27th International Symposium on Transport Phenomena (ISTP-27) (USB Flash Drive), 8 Pages, 2016/09
In this study, Unsteady Reynolds Averaged Navier-Stokes equation (U-RANS) approach with the Reynolds Stress Model using commercial CFD code has been applied to the flow through triple short-elbows under a high Re (1.010). This numerical simulation has utilized a 1/7 scaled water experiment of the advanced SFR cold-leg piping in order to investigate the flow structure in a three-dimensionally connected triple elbows. As a result, applicability of the U-RANS numerical simulation method was confirmed by comparison between the numerical and experimental results under Re = 1.010 condition. The simulation has also shown that flow fields in the 1st elbow was different from that in the 2nd elbow and pressure fluctuation in the 2nd elbow was slightly larger than that in the 1st elbow because of the presence of their large vortex flow structure. This large vortex was generated due to a short distance between two elbows. On the other hand, the flow structure in the 3rd elbow was similar to that in the 1st elbow because the swirling flow formed in the 2nd elbow was alleviated in the 3rd elbow inlet which was located long way away from the 2nd elbow.
Yamano, Hidemasa; Xu, Y.*; Sago, Hiromi*; Hirota, Kazuo*; Baba, Takeo*
Proceedings of 2016 International Congress on Advances in Nuclear Power Plants (ICAPP 2016) (CD-ROM), p.1029 - 1038, 2016/04
This study conducted the flow-induced vibration evaluation of the primary hot-leg piping in the demonstration reactor design of advanced loop-type sodium-cooled fast reactor in order to confirm the integrity of the piping. Following the description of the primary hot-leg piping design and a design guideline of the flow-induced vibration evaluation, this paper describes mainly the flow-induced vibration evaluation and thereby the integrity assessment. In the fatigue evaluation for the flow-induced vibration, the pipe stresses considering the stress concentration factor and so on, at representative locations were less than the design fatigue limit. Therefore, this evaluation confirmed the integrity of the primary hot-leg piping in the demonstration reactor.