start-ver=1.4 cd-journal=joma no-vol=137 cd-vols= no-issue=23 article-no= start-page=235104 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250617 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Imaging valley-vortex edge modes in a phononic crystal at ultrahigh frequencies en-subtitle= kn-subtitle= en-abstract= kn-abstract=We perform optical measurements and numerical simulations of guided phonon propagation in novel topological phononic crystal structures at ultrahigh frequencies. The structures support valley-polarized states that exhibit an energy vortex nature and propagate with high efficiency at domain boundaries because backscattering is suppressed due to conservation of time reversal symmetry. We extract frequency- and time-resolved spatial mode patterns and k-space images, together with dispersion relations. We investigate the conditions required for robust propagation along interfaces and thereby observe very high efficiency waveguiding. en-copyright= kn-copyright= en-aut-name=OtsukaP. H. en-aut-sei=Otsuka en-aut-mei=P. H. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TomodaM. en-aut-sei=Tomoda en-aut-mei=M. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HatanakaD. en-aut-sei=Hatanaka en-aut-mei=D. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamaguchiH. en-aut-sei=Yamaguchi en-aut-mei=H. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TsurutaK. en-aut-sei=Tsuruta en-aut-mei=K. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MatsudaO. en-aut-sei=Matsuda en-aut-mei=O. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Division of Applied Physics, Graduate School of Engineering, Hokkaido University kn-affil= affil-num=2 en-affil=Division of Applied Physics, Graduate School of Engineering, Hokkaido University kn-affil= affil-num=3 en-affil=NTT Basic Research Laboratories, NTT Corporation kn-affil= affil-num=4 en-affil=NTT Basic Research Laboratories, NTT Corporation kn-affil= affil-num=5 en-affil=Department of Electrical and Electronic Engineering, Okayama University kn-affil= affil-num=6 en-affil=Division of Applied Physics, Graduate School of Engineering, Hokkaido University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=96 cd-vols= no-issue=3 article-no= start-page=033907 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250325 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Development of density measurement at high pressure and high temperature using the x-ray absorption method combined with laser-heated diamond anvil cell en-subtitle= kn-subtitle= en-abstract= kn-abstract=The densities of liquid materials at high pressures and high temperatures are important information to understand the elastic behavior of liquids at extreme conditions, which is closely related to the formation and evolution processes of the Earth and planetary interiors. The x-ray absorption method is an effective method to measure the density of non-crystalline materials at high pressures. However, the temperature condition of the x-ray absorption method using a diamond anvil cell (DAC) has been limited to 720 K to date. To significantly expand the measurable temperature condition of this method, in this study, we developed a density measurement technique using the x-ray absorption method in combination with a laser-heated DAC. The density of solid Ni was measured up to 26 GPa and 1800 K using the x-ray absorption method and evaluated by comparison with the density obtained from the x-ray diffraction. The density of solid Ni with a thickness >17 μm was determined with an accuracy of 0.01%–2.2% (0.001–0.20 g/cm3) and a precision of 0.8%–1.8% (0.07–0.16 g/cm3) in the x-ray absorption method. The density of liquid Ni was also determined to be 8.70 ± 0.15–8.98 ± 0.38 g/cm3 at 16–23 GPa and 2230–2480 K. Consequently, the temperature limit of the x-ray absorption method can be expanded from 720 to 2480 K by combining it with a laser-heated DAC in this study. en-copyright= kn-copyright= en-aut-name=TerasakiHidenori en-aut-sei=Terasaki en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KaminaHiroyuki en-aut-sei=Kamina en-aut-mei=Hiroyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawaguchiSaori I. en-aut-sei=Kawaguchi en-aut-mei=Saori I. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KondoTadashi en-aut-sei=Kondo en-aut-mei=Tadashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MoriokaKo en-aut-sei=Morioka en-aut-mei=Ko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=TsuruokaRyo en-aut-sei=Tsuruoka en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SakuraiMoe en-aut-sei=Sakurai en-aut-mei=Moe kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=YonedaAkira en-aut-sei=Yoneda en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=KamadaSeiji en-aut-sei=Kamada en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=HiraoNaohisa en-aut-sei=Hirao en-aut-mei=Naohisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=3 en-affil=Japan Synchrotron Radiation Research Institute, SPring-8 kn-affil= affil-num=4 en-affil=Department of Earth and Space Science, Osaka University kn-affil= affil-num=5 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=6 en-affil=Department of Earth and Space Science, Osaka University kn-affil= affil-num=7 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=8 en-affil=Department of Earth and Space Science, Osaka University kn-affil= affil-num=9 en-affil=AD Science Incorporation kn-affil= affil-num=10 en-affil=Japan Synchrotron Radiation Research Institute, SPring-8 kn-affil= END start-ver=1.4 cd-journal=joma no-vol=126 cd-vols= no-issue=1 article-no= start-page=012901 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250102 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Dynamic domain motion enhancing electro-optic performance in ferroelectric films en-subtitle= kn-subtitle= en-abstract= kn-abstract=With the rapid advancement of information technology, there is a pressing need to develop ultracompact and energy-efficient thin-film-based electro-optic (EO) devices. A high EO coefficient in ferroelectric materials is crucial. However, substrate clamping can positively or negatively influence various physical properties, including the EO response of these films, thus complicating the development of next-generation thin-film-based devices. This study demonstrates that reversible dynamic domain motion, achieved through substrate clamping, significantly enhances the EO coefficient in epitaxial ferroelectric rhombohedral Pb(Zr, Ti)O3 thin films, where the (111) and (⁠ 111⁠) domains coexist with distinct optical axes. In principle, this approach can be applied to different film-substrate systems, thereby contributing to the advancement of sophisticated EO devices based on ferroelectrics. en-copyright= kn-copyright= en-aut-name=KondoShinya en-aut-sei=Kondo en-aut-mei=Shinya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OkamotoKazuki en-aut-sei=Okamoto en-aut-mei=Kazuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SakataOsami en-aut-sei=Sakata en-aut-mei=Osami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TeranishiTakashi en-aut-sei=Teranishi en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KishimotoAkira en-aut-sei=Kishimoto en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NagasakiTakanori en-aut-sei=Nagasaki en-aut-mei=Takanori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamadaTomoaki en-aut-sei=Yamada en-aut-mei=Tomoaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Energy Engineering, Nagoya University kn-affil= affil-num=3 en-affil=Japan Synchrotron Radiation Research Institute (JASRI) kn-affil= affil-num=4 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Energy Engineering, Nagoya University kn-affil= affil-num=7 en-affil=Department of Energy Engineering, Nagoya University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=159 cd-vols= no-issue=19 article-no= start-page=194504 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20231121 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Efficiency and energy balance for substitution of CH4 in clathrate hydrates with CO2 under multiple-phase coexisting conditions en-subtitle= kn-subtitle= en-abstract= kn-abstract=Many experimental and theoretical studies on CH4–CO2 hydrates have been performed aiming at the extraction of CH4 as a relatively clean energy resource and concurrent sequestration of CO2. However, vague or insufficient characterization of the environmental conditions prevents us from a comprehensive understanding of even equilibrium properties of CH4–CO2 hydrates for this substitution. We propose possible reaction schemes for the substitution, paying special attention to the coexisting phases, the aqueous and/or the fluid, where CO2 is supplied from and CH4 is transferred to. We address the two schemes for the substitution operating in three-phase and two-phase coexistence. Advantages and efficiencies of extracting CH4 in the individual scheme are estimated from the chemical potentials of all the components in all the phases involved in the substitution on the basis of a statistical mechanical theory developed recently. It is found that although substitution is feasible in the three-phase coexistence, its working window in temperature–pressure space is much narrower compared to the two-phase coexistence condition. Despite that the substitution normally generates only a small amount of heat, a large endothermic substitution is suggested in the medium pressure range, caused by the vaporization of liquid CO2 due to mixing with a small amount of the released CH4. This study provides the first theoretical framework toward the practical use of hydrates replacing CH4 with CO2 and serves as a basis for quantitative planning. en-copyright= kn-copyright= en-aut-name=TanakaHideki en-aut-sei=Tanaka en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumotoMasakazu en-aut-sei=Matsumoto en-aut-mei=Masakazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YagasakiTakuma en-aut-sei=Yagasaki en-aut-mei=Takuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=3 en-affil=Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=161 cd-vols= no-issue=21 article-no= start-page=214501 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20241202 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The nature of the hydrophobic interaction varies as the solute size increases from methane’s to C60’s en-subtitle= kn-subtitle= en-abstract= kn-abstract=The hydrophobic interaction, often combined with the hydrophilic or ionic interactions, makes the behavior of aqueous solutions very rich and plays an important role in biological systems. Theoretical and computer simulation studies have shown that the water-mediated force depends strongly on the size and other chemical properties of the solute, but how it changes with these factors remains unclear. We report here a computer simulation study that illustrates how the hydrophobic pair interaction and the entropic and enthalpic terms change with the solute size when the solute–solvent weak attractive interaction is unchanged with the solute size. The nature of the hydrophobic interaction changes qualitatively as the solute size increases from that of methane to that of fullerene. The potential of mean force between small solutes has several well-defined extrema, including the third minimum, whereas the potential of mean force between large solutes has the deep contact minimum and the large free-energy barrier between the contact and the water-bilayer separated configurations. The difference in the potential of mean force is related to the differences in the water density, energy, and hydrogen bond number distributions in the vicinity of the pairs of hydrophobic solutes. en-copyright= kn-copyright= en-aut-name=NaitoHidefumi en-aut-sei=Naito en-aut-mei=Hidefumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SumiTomonari en-aut-sei=Sumi en-aut-mei=Tomonari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KogaKenichiro en-aut-sei=Koga en-aut-mei=Kenichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=125 cd-vols= no-issue=2 article-no= start-page=023104 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240708 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Enhanced thermal conductivity of fluids by percolating high-concentration few-layer graphene en-subtitle= kn-subtitle= en-abstract= kn-abstract=High-performance and small-sized heat exchangers have been demanded due to the miniaturization and higher output of electronic devices, lasers, and energy harvesting/storage systems. Graphene nanosheet suspension has attracted attention as a next-generation nanofluid because of its high thermal conductivity and low pressure drop, while being dispersed stably without any additives. Graphene-based nanofluids have been mostly investigated using graphene oxide, and there are a few studies on pure graphene because of the limitation in mass production and stabilization at high concentrations of graphene. In this study, we prepared a 10 wt. % high-concentration few-layer graphene suspension by pulverizing graphite particles. Scanning electron microscopy, atomic force microscopy, and Raman spectra confirmed the few-layer graphene is formed in the suspension. The thermal conductivity of the suspension increased with concentration and suddenly jumped at a specific concentration. Furthermore, a significant improvement in thermal conductivity of >40% compared to base liquid was confirmed at 10 wt. % graphene content. A similar trend was observed for electrical resistance; 10 wt. % graphene suspension showed 62% lower resistance than that of 1 wt. %. These results suggest the percolation of graphene in a liquid, which has not been observed for graphene-based materials in previous research. en-copyright= kn-copyright= en-aut-name=IshiiKeiko en-aut-sei=Ishii en-aut-mei=Keiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OgiyamaTakahiro en-aut-sei=Ogiyama en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FumotoKoji en-aut-sei=Fumoto en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NishinaYuta en-aut-sei=Nishina en-aut-mei=Yuta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=College of Science and Engineering, Chuo University kn-affil= affil-num=2 en-affil=College of Science and Engineering, Aoyama Gakuin University kn-affil= affil-num=3 en-affil=College of Science and Engineering, Aoyama Gakuin University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=36 cd-vols= no-issue=3 article-no= start-page=036617 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240319 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effect of non-local near-resonant interactions of Rossby waves on formation of large-scale zonal flows in unforced two-dimensional turbulence on rotating sphere en-subtitle= kn-subtitle= en-abstract= kn-abstract=This study investigates the effect of nonlinear interactions of Rossby waves on large-scale zonal flow formation in two-dimensional turbulence on a rotating sphere. The coefficients of nonlinear interactions are first calculated. Then, the non-local, near-resonant, and non-local near-resonant interactions are investigated in detail. The results show that the formation of large-scale westward circumpolar zonal flows is directly caused by non-local energy transfer due to the three-wave near-resonant interactions of Rossby waves. en-copyright= kn-copyright= en-aut-name=HagimoriYusuke en-aut-sei=Hagimori en-aut-mei=Yusuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ObuseKiori en-aut-sei=Obuse en-aut-mei=Kiori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamadaMichio en-aut-sei=Yamada en-aut-mei=Michio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Research Institute for Mathematical Sciences, Kyoto University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=160 cd-vols= no-issue=14 article-no= start-page=144304 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240409 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Analysis on high-resolution spectrum of the S1–S0 transition of free-base phthalocyanine en-subtitle= kn-subtitle= en-abstract= kn-abstract=A high-resolution absorption spectrum of the S-1-S-0 transition of free-base phthalocyanine was observed and analyzed with improved reliability. The spectrum, with a partially resolved rotational structure, was obtained by using the buffer-gas cooling technique and a single-mode tunable laser. Our new analysis reveals that the S-1 <- S-0 0(0)(0) band belongs to the a-type transition, where the electronic transition moment aligns parallel to the NH-HN direction, allowing the assignment of the S-1 state to B-1(3u). These results agree with a prior study using supersonic expansion and are well supported by theoretical calculations. Interestingly, the rotational constant B in the S-1 state, which is often smaller than that in the ground state for typical molecules, was found to be slightly larger than that in the S-0 (1)A(g) state. This suggests a change in the character of pi bonds with the electronic excitation. en-copyright= kn-copyright= en-aut-name=MiyamotoYuki en-aut-sei=Miyamoto en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HiramotoAyami en-aut-sei=Hiramoto en-aut-mei=Ayami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IwakuniKana en-aut-sei=Iwakuni en-aut-mei=Kana kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KumaSusumu en-aut-sei=Kuma en-aut-mei=Susumu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=EnomotoKatsunari en-aut-sei=Enomoto en-aut-mei=Katsunari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NakayamaNaofumi en-aut-sei=Nakayama en-aut-mei=Naofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=BabaMasaaki en-aut-sei=Baba en-aut-mei=Masaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=3 en-affil=Institute for Laser Science, University of Electro-Communications kn-affil= affil-num=4 en-affil=Atomic, Molecular and Optical Physics Laboratory, RIKEN kn-affil= affil-num=5 en-affil=Department of Physics, University of Toyama kn-affil= affil-num=6 en-affil=CONFLEX Corporation kn-affil= affil-num=7 en-affil=Molecular Photoscience Research Center, Kobe University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=160 cd-vols= no-issue=9 article-no= start-page=094101 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240301 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=GenIce-core: Efficient algorithm for generation of hydrogen-disordered ice structures en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ice is different from ordinary crystals because it contains randomness, which means that statistical treatment based on ensemble averaging is essential. Ice structures are constrained by topological rules known as the ice rules, which give them unique anomalous properties. These properties become more apparent when the system size is large. For this reason, there is a need to produce a large number of sufficiently large crystals that are homogeneously random and satisfy the ice rules. We have developed an algorithm to quickly generate ice structures containing ions and defects. This algorithm is provided as an independent software module that can be incorporated into crystal structure generation software. By doing so, it becomes possible to simulate ice crystals on a previously impossible scale. en-copyright= kn-copyright= en-aut-name=MatsumotoMasakazu en-aut-sei=Matsumoto en-aut-mei=Masakazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YagasakiTakuma en-aut-sei=Yagasaki en-aut-mei=Takuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TanakaHideki en-aut-sei=Tanaka en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University kn-affil= affil-num=3 en-affil=Toyota Physical and Chemical Research Institute kn-affil= END start-ver=1.4 cd-journal=joma no-vol=123 cd-vols= no-issue=23 article-no= start-page=231601 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20231204 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Water/ice mixture- and freezing-front motion in a non-isothermal liquid bridge en-subtitle= kn-subtitle= en-abstract= kn-abstract=We experimentally investigate the water/ice mixture- and freezing-front behavior in a water liquid bridge under isothermal and non-isothermal conditions. We find rapid propagation, temporary suspension, and regression of the water/ice mixture front, and finally, it merges with the freezing front when part of the liquid bridge is higher than the freezing temperature. However, freezing-front propagation follows dendritic ice formation, and a protrusion forms at the middle of the liquid bridge as long as the whole liquid bridge is lower than the freezing temperature. We explain those phenomena by quasi-stationary heat-transfer considerations. en-copyright= kn-copyright= en-aut-name=YamadaYutaka en-aut-sei=Yamada en-aut-mei=Yutaka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OkanoKodai en-aut-sei=Okano en-aut-mei=Kodai kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IsobeKazuma en-aut-sei=Isobe en-aut-mei=Kazuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HoribeAkihiko en-aut-sei=Horibe en-aut-mei=Akihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=School of Engineering, Okayama University kn-affil= affil-num=3 en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=17 cd-vols= no-issue=5 article-no= start-page=054107 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20231016 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Diamond quantum sensors in microfluidics technology en-subtitle= kn-subtitle= en-abstract= kn-abstract=Diamond quantum sensing is an emerging technology for probing multiple physico-chemical parameters in the nano- to micro-scale dimensions within diverse chemical and biological contexts. Integrating these sensors into microfluidic devices enables the precise quantification and analysis of small sample volumes in microscale channels. In this Perspective, we present recent advancements in the integration of diamond quantum sensors with microfluidic devices and explore their prospects with a focus on forthcoming technological developments. en-copyright= kn-copyright= en-aut-name=FujiwaraMasazumi en-aut-sei=Fujiwara en-aut-mei=Masazumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=156 cd-vols= no-issue=22 article-no= start-page=221104 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220614 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Osmotic second virial coefficients for hydrophobic interactions as a function of solute size en-subtitle= kn-subtitle= en-abstract= kn-abstract=To gain quantitative insight into how the overall strength of the hydrophobic interaction varies with the molecular size, we calculate osmotic second virial coefficients B for hydrophobic spherical molecules of different diameters σ in water based on molecular simulation with corrections to the finite-size and finite-concentration effects. It is shown that B (<0) changes by two orders of magnitude greater as σ increases twofold and its solute-size dependence is best fit by a power law B ∝ σ α with the exponent α ≃ 6, which contrasts with the cubic power law that the second virial coefficients of gases obey. It is also found that values of B for the solutes in a nonpolar solvent are positive but they obey the same power law as in water. A thermodynamic identity for B derived earlier [K. Koga, V. Holten, and B. Widom, J. Phys. Chem. B 119, 13391 (2015)] indicates that if B is asymptotically proportional to a power of σ, the exponent α must be equal to or greater than 6. en-copyright= kn-copyright= en-aut-name=NaitoHidefumi en-aut-sei=Naito en-aut-mei=Hidefumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OkamotoRyuichi en-aut-sei=Okamoto en-aut-mei=Ryuichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SumiTomonari en-aut-sei=Sumi en-aut-mei=Tomonari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KogaKenichiro en-aut-sei=Koga en-aut-mei=Kenichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=3 article-no= start-page=035109 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220303 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Magnetic thickness measurement for various iron steels using magnetic sensor and effect of electromagnetic characteristics en-subtitle= kn-subtitle= en-abstract= kn-abstract=The diagnosis and prevention of the deterioration of iron-steel infrastructure has become an important social issue in recent years. The thickness measurement technique (extremely low-frequency eddy current testing (ELECT)) using a magnetic sensor for detecting steel corrosion at extreme frequency ranges has been previously reported. Using the calibration curves based on the correlation between the phase of the detected magnetic signal and the plate thickness, the plate thickness reduction caused by corrosion can be estimated from the detected phase signal. Iron-steel materials have large changes in electromagnetic characteristics; therefore, the reference calibration data for each type of iron-steel are required for plate thickness estimation. In this study, the effect of electromagnetic characteristics on the magnetic thickness measurement was investigated to improve the thickness estimation. Four types of iron-steel plates (SS400, SM400A, SM490A, and SMA400AW) with thicknesses ranging from 1 mm to 18 mm were measured by ELECT, and the phase change at multiple frequencies of each plate were analyzed. The shift in the phase and linearity regions of the calibration curves for each type of steel plate was observed. To analyze this shift phenomenon, the electromagnetic characteristics (permeability mu and conductivity sigma) of each type of steel were measured. Compared with the permeability mu and conductivity sigma of each steel plate in the applied magnetic field strength range, the product (sigma mu) for various steel plates decreased in the following order: SM400 > SS400 >SMA400AW > SM490A. The product of mu and sigma is related to the skin depth, indicating the electromagnetic wave attenuation and eddy current phase shift in the material. Therefore, each shift in the calibration curve of each type of iron steel is explained by the changes in the parameters sigma and mu. en-copyright= kn-copyright= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HayashiMinoru en-aut-sei=Hayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakamiTaisei en-aut-sei=Kawakami en-aut-mei=Taisei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=AdachiShoya en-aut-sei=Adachi en-aut-mei=Shoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=IshikawaToshiyuki en-aut-sei=Ishikawa en-aut-mei=Toshiyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=SaariMohd Mawardi en-aut-sei=Saari en-aut-mei=Mohd Mawardi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=HoriKengo en-aut-sei=Hori en-aut-mei=Kengo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=HisazumiKazumasa en-aut-sei=Hisazumi en-aut-mei=Kazumasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=TominagaTomonori en-aut-sei=Tominaga en-aut-mei=Tomonori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Faculty of Environmental and Urban Engineering Department of Civil, Environmental and Applied System Engineering, Kansai University kn-affil= affil-num=8 en-affil=Faculty of Electrical and Electronic Engineering, Universiti Malaysia Pahang kn-affil= affil-num=9 en-affil=Nippon Steel Metal Products Co., Ltd. kn-affil= affil-num=10 en-affil=Nippon Steel Corp. kn-affil= affil-num=11 en-affil=Nippon Steel Corp. kn-affil= END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=7 article-no= start-page=75224 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210726 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Design and validation of microfluidic parameters of a microfluidic chip using fluid dynamics en-subtitle= kn-subtitle= en-abstract= kn-abstract=The internal fluidic parameters of microfluidic channels must be analyzed to solve fundamental microfluidic problems, including microscale transport problems involving thermal analysis, chemical reactivity, velocity, pressure drop, etc., for developing good-quality chemical and biological products. Therefore, the characterization and optimization of the interaction of chemical and biological solutions through microfluidic channels are vital for fluid flow design and engineering for quality assurance in microfluidic platforms. As the internal structures and kinetics of microfluidic channels are becoming increasingly complex, experiments involving optimal fluidic and transport designs are challenging to perform with high accuracy. However, highly integrated simulation tools can guide researchers without specialized computational fluid backgrounds to design numerical prototypes of highly integrated devices. In this study, a microfluidic chip with two inlet wells and one outlet well was fabricated from polydimethylsiloxane following which simulations were performed using an ANSYS Fluent tool influenced by computational fluid dynamics at a nearly identical scale. The pressure drop and velocity profiles of the interaction of two pH buffer solutions (pH 4 and 10) through the designed microfluidic chip were qualitatively estimated from experimental data analysis and validated with the simulation results obtained from the CFD-influenced ANSYS Fluent tool. en-copyright= kn-copyright= en-aut-name=AhmedFeroz en-aut-sei=Ahmed en-aut-mei=Feroz kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YoshidaYuichi en-aut-sei=Yoshida en-aut-mei=Yuichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WangJin en-aut-sei=Wang en-aut-mei=Jin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Department of Medical Bioengineering, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Department of Medical Bioengineering, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Department of Medical Bioengineering, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Department of Medical Bioengineering, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Department of Medical Bioengineering, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=154 cd-vols= no-issue=9 article-no= start-page=094502 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210301 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Formation of hot ice caused by carbon nanobrushes. II. Dependency on the radius of nanotubes en-subtitle= kn-subtitle= en-abstract= kn-abstract=Stable crystalline structures of confined water can be different from bulk ice. In Paper I [T. Yagasaki et al., J. Chem. Phys. 151, 064702 (2019)] of this study, it was shown, using molecular dynamics (MD) simulations, that a zeolite-like ice structure forms in nanobrushes consisting of (6,6) carbon nanotubes (CNTs) when the CNTs are located in a triangle arrangement. The melting temperature of the zeolite-like ice structure is much higher than the melting temperature of ice Ih when the distance between the surfaces of CNTs is ∼0.94 nm, which is the best spacing for the bilayer structure of water. In this paper, we perform MD simulations of nanobrushes of CNTs that are different from (6,6) CNTs in radius. Several new porous ice structures form spontaneously in the MD simulations. A stable porous ice forms when the radius of its cavities matches the radius of the CNTs well. All cylindrical porous ice structures found in this study can be decomposed into a small number of structural blocks. We provide a new protocol to classify cylindrical porous ice crystals on the basis of this decomposition. en-copyright= kn-copyright= en-aut-name=MatsumotoMasakazu en-aut-sei=Matsumoto en-aut-mei=Masakazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YagasakiTakuma en-aut-sei=Yagasaki en-aut-mei=Takuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TanakaHideki en-aut-sei=Tanaka en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=10 cd-vols= no-issue=1 article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=202001 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Laser monitoring of dynamic behavior of magnetic nanoparticles in magnetic field gradient en-subtitle= kn-subtitle= en-abstract= kn-abstract=Manipulation of magnetic nanoparticles (MNP) by an external magnetic field has been widely studied in the fields of biotechnology and medicine for collecting and/or reacting biomaterials in the solutions. Here, dynamic behaviors of MNP in solution under changing gradient magnetic field were investigated using our newly developed laser transmission system (LTS) with a variable magnetic field manipulator. The manipulator consists of a moving permanent magnet placed beside the optical cell filled with MNP solution. A laser beam was focused on the cell and the transmitted laser beam was detected by a silicon photodiode, so that the localized concentration of the MNP at the focused area could be evaluated by the intensity of transmitted laser beam. In this study, the LTS was applied to evaluate dynamic behaviors of MNP in serum solution. Dispersion and aggregation of MNP in the solution were evaluated. While time evolution of dispersion depends on the serum concentration, the behavior during aggregation by the magnetic field was independent of the serum concentration. A series of measurements for zeta-potentials, distributions of particle size, and magnetization distributions was carried out to understand this difference in the behavior. The results indicated that a Brownian motion was main force to distribute the MNP in the solution; on the other hand, the magnetic force to the MNP mainly affected the behavior during aggregation of the MNP in the solution. en-copyright= kn-copyright= en-aut-name=TsunashimaKenta en-aut-sei=Tsunashima en-aut-mei=Kenta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=JinnoKatsuya en-aut-sei=Jinno en-aut-mei=Katsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HiramatsuBunta en-aut-sei=Hiramatsu en-aut-mei=Bunta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FujimotoKayo en-aut-sei=Fujimoto en-aut-mei=Kayo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SaariMohd Mawardi en-aut-sei=Saari en-aut-mei=Mohd Mawardi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Faculty of Electrical & Electronic Engineering, Universiti Malaysia Pahang kn-affil= affil-num=8 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=2180 cd-vols= no-issue= article-no= start-page=020028 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191210 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Consideration to Display Operator Support Information to Human Operators under High Mental Pressure en-subtitle= kn-subtitle= en-abstract= kn-abstract= Operator support systems are extensively studied and developed to support human operators for their activities in especially an abnormal condition of a nuclear power plant. By the advancement of computer technology and artificial intelligence, an operator support system can provide detailed support information based on detailed models and utilizing detailed simulation of plant dynamics and/or complicated inference algorithms. However, human operators may not understand the detailed support information under high mental pressure in an abnormal plant condition. In such a case, it is important how to provide essential and understandable support information. This paper deals with a technique to simplify functional models in order to display operator support information that is generated based on detailed functional models. This paper defines eight cognitive states of human operators from the viewpoint of cognitive abilities of human. In addition, three ways to simplify functional models are identified. en-copyright= kn-copyright= en-aut-name=GofukuAkio en-aut-sei=Gofuku en-aut-mei=Akio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= en-keyword=operator support system kn-keyword=operator support system en-keyword= information display kn-keyword= information display en-keyword=model simplification kn-keyword=model simplification en-keyword=cognitive state kn-keyword=cognitive state END