http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Two competing soft modes and an unusual phase transition in the stuffed tridymite-type oxideBaAl2O4
Ishii, Y.,Mori, S.,Nakahira, Y.,Moriyoshi, C.,Park, J.,Kim, B. G.,Moriwake, H.,Taniguchi, H.,Kuroiwa, Y. American Physical Society 2016 Physical Review B Vol.93 No.13
<P>We investigated the structural phase transition of BaAl2O4, which has a network structure with corner-sharing AlO4 tetrahedra, via synchrotron x-ray thermal diffuse scattering measurements and first-principles calculations. BaAl2O4 shows the structural phase transition at T-C = 451.4 K from the P6(3)22 parent crystal structure to the low-temperature superstructure with a cell volume of 2a x 2b x c. This phase transition is unusual, in which two energetically competing phonon modes at M and K points soften simultaneously. When approaching T-C from above, the K-point mode appears first. However, this K-point mode is overcome by the later-developed M-point mode. The thermal diffuse scattering intensities from both modes increase sharply at T-C; therefore, both modes soften simultaneously. The first-principles calculations demonstrate that the M-point mode is electrostatically more preferable than the K-point mode and determines the eventual low-temperature structure, although these two modes are competing energetically. This competition is characteristic of BaAl2O4, which is ascribed to the structurally flexible network structure of this compound.</P>
Size-controlled Growth of Fe Nanoparticles in Gas Flow Sputtering Process
H. Sakuma,H. Aoshima,K. Ishii 한국자기학회 2006 Journal of Magnetics Vol.11 No.3
Iron (Fe) nanoparticles with diameters of 15?50 nm were obtained by the gas flow sputtering process. The particle size varied with the discharge current and Ar gas flow rate. While the particle size increased with the discharge current at an Ar flow rate of 500 sccm, the distribution of the particle diameters splits into two peaks for an Ar flow rate of 200 sccm and low discharge current. At 200 sccm, particles of about 50 nm were obtained regardless of the discharge current; in addition, smaller particles with diameters depending on the discharge current were also obtained. The changes in the particle size are discussed in terms of Fe vapor density and growth period.
Yanagisawa, Y.,Suetomi, Y.,Piao, R.,Yamagishi, K.,Takao, T.,Hamada, M.,Saito, K.,Ohki, K.,Yamaguchi, T.,Nagaishi, T.,Kitaguchi, H.,Ueda, H.,Shimoyama, J.,Ishii, Y.,Tomita, M.,Maeda, H. The Korea Institute of Applied Superconductivity a 2018 초전도와 저온공학 Vol.20 No.2
The present article briefly overviews the plan for a new project on joint technology for HTS wires/cables and describes the development plan for the world's highest field NMR magnet, which is a major development item in the project. For full-fledged social implementation of superconducting devices, high temperature superconducting (HTS) wire is a key technology since they can be cooled by liquid nitrogen and they can generate a super-high magnetic field of >>24 T at liquid helium temperatures. However, one of the major drawbacks of the HTS wires is their availability only in short lengths of a single piece of wire. This necessitates a number of joints being installed in superconducting devices, resulting in a difficult manufacturing process and a large joint resistance. In Japan, a large-scale project has commenced, including two technical demonstration items: (i) Development of superconducting joints between HTS wires, which are used in the world's highest field 1.3 GHz (30.5 T) NMR magnet in persistent current mode; the joints performance is evaluated based on NMR spectra for proteins. (ii) Development of ultra-low resistive joints between DC superconducting feeder cables for railway systems. The project starts a new initiative of next generation super-high field NMR development as well as that of realization of better superconducting power cables.
Endo, R.,Ishii, A.,Nakanishi, A.,Nabenishi, H.,Ashizawa, K.,Tsuzuki, Y. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.11
We investigated the effects of various concentrations of ${\beta}$-hydroxybutyrate (BHB, 0, 0.1, 1 and 10 mM), a ketone body, added to chemically-defined maturation medium with or without energy substrates (glucose, pyruvate and lactate) on nuclear maturation rates up to the metaphase stage of the second meiotic division (M-II stage). In addition, we also assessed the influence of BHB on glutathione content, sperm penetration rate and embryonic development up to the blastocyst stage of oocytes matured under the presence of these energy substrates. Nuclear maturation rates up to the M-II stage of oocytes matured with BHB in each concentration group did not show a significant increase compared with the control (0 mM) groups in both the presence and absence of energy substrates. Although glutathione contents were not significantly different in each BHB concentration group, the sperm penetration rate in the 1 mM BHB group was significantly higher (p<0.05) and the embryonic development rate of oocytes up to the blastocyst stage was significantly lower (p<0.05) than the respective values of the control groups. These results suggest that BHB added to a chemically-defined maturation medium may stimulate sperm penetration while inhibiting embryonic development of porcine oocytes.