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Giant Volume Magnetostriction Caused by Itinerant Electron Metamagnetic Transition and Pronounced Invar Effects in La(Fe_xSi_(1-x))_(13) Compounds

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Journal of Materials Science & Technology 2000年第2期16卷 167-171页

作者： K.Fukamichi and A.Fujita (department of Materials Science, graduate school of engineering, tohoku university, Aoba-yama 02, sendai 980-8579, japan) department of Materials Science Graduate School of Engineering Tohoku University Aoba-yama 02 Sendai 980-8579 Japan

A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_C for x=0.88 is huge of about 1.5%, which is caused by a large magnetic moment induced by the IEM transition. These compounds have a possibility for practical applications as giant magnetostrictive materials. Pronounced Invar effects bring about a negative thermal expansion below TC, closely correlated with the negative mode-mode coupling among spin fluctuations.

关键词： Compounds Fe_xSi Giant Volume Magnetostriction Caused by Itinerant Electron Metamagnetic Transition and Pronounced Invar Effects in La

Fluid Flow Behavior of Liquid in Cylindrical Vessels Stirred by One or Two Air Jets

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 170-177页

作者： Lifeng Zhang, Shoji Taniguchi, Kaike Cai, Ying Qu ( department of Metallurgy graduate school of engineering, tohoku university, sendai 980-579 japan Metallurgy school, university of Science and Technology Beijing, Beijing 100083, China) department of Metallurgy Graduate School of Engineering Tohoku University Sendai 980-8579 Japan Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Based on the two-phase model (Eulerian-Eulerian model), the three dimensional fluid flow in water and that liquid steel systems stirred by one or two multiple gas jets are simulated. In the Eulerian-Eulerian two-phase model, the gas and the liquid phase are considered to be two different continuous fluids interacting with each other through the finite inter-phase areas. The exchange between the phases is represented by source terms in conversation equations. Turbulence is assumed to be a property of the liquid phase. A new turbulence modification - model is introduced to consider the bubbles movement contribution to and . The dispersion of phases due to turbulence is represented by introducing a diffusion term in mass conservation equation. The mathematical simulation agrees well with the experiment results. The study results indicate that the distance of two nozzles has big effect on fluid flow behavior in the vessel. Using two gas injection nozzles at the half radii of one diameter of the bottom generates a much better mixing than with one nozzle under the condition of the same total gas flow rate.

关键词： fluid flow two-phase Eulerian-Eulerian model model mathematical simulation

Localized Corrosion in Copper Tubes by Volatile Organic Substance

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 129-132页

作者： Takenori Notoya(Laboratory of Corrosion engineering, graduate school of engineering, Hokkaido university, Sapporo, japan) Laboratory of Corrosion engineering Graduate School of Engineering Hokkaido University Sapporo Japan

An unusual form of localized corrsion in copper tubes was detected early in service and in leakage tests after *** morphology of this corrosion is similar to that of an ant's nest when viewed in cross section. The cor... 详细信息

关键词： copper tubes localized corrosion volatile organic substance heat-transfer units

A Self-consistent Calculation and an Anisotropic Wavelength Cut off Energy of Spin-wave Spectrumin Magnetic Tunnel Junctions

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Journal of Materials Science & Technology 2001年第2期17卷 197-202页

作者： Xiufeng HAN State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China Terunobu Miyazaki department of applied Physics, graduate school of engineering, tohoku university, Aoba-yama 08, sendai 980-8579, Japa Chinese Acad Sci Inst Phys State Key Lab Magnetism Beijing 100080 Peoples R China tohoku Univ Grad Sch Engn Dept Appl Phys Sendai Miyagi 9808579 Japan

Temperature dependence of tunnel magnetoresistance (TMR) ratio, resistance, and coercivity from 4.2 K to room temperature (RT), applied de bias voltage dependence of the TMR ratio and resistances at 4.2 K and RT, tunnel current I and dynamic conductance dI/dV as functions of the de bias voltage at 4.2 K, and inelastic electron tunneling (IET) spectroscopy, d(2)I/dV(2) versus V, at 4.2 K for a tunnel junction of Ta(5 nm)/Ni79Fe21(25 nm)/Ir22Mn78(12 nm)/Co75Fe25(4 nm)/Al(0.8 nm)-oxide/Co75Fe25(4 nm)/Ni79Fe21(25 nm)/Ta(5 nm) were systematically investigated. High TMR ratio of 59.2% at 4.2 K and 41.3% at RT were observed for this junction after annealing at 275 degreesC for an hour. The temperature dependence of TMR ratio and resistances from 4.2 to 300 K at 1.0 mV bias and the de bias voltage dependence of TMR ratio at 4.2 K from 0 to 80 mV can be evaluated by a comparison of self-consistent calculations with the experimental data based on the magnon-assisted inelastic excitation model and theory. An anisotropic wavelength cutoff energy of spin-wave spectrum in magnetic tunnel junctions (MTJs) was suggested, which is necessary for self-consistent calculations, based on a series of IET spectra observed in the MTJs.

关键词： off TMR A Self-consistent Calculation and an Anisotropic Wavelength Cut Energy of Spin-wave Spectrumin Magnetic Tunnel Junctions wave Figure than

High Diastereoselectivity in the Conjugate Addition of Functionalized Alcohols to a Chiral(E)-Nitroalkene

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Chinese Chemical Letters 1999年第8期10卷 629-632页

作者： Qian CHENG Takayuki ORITANI Alfred HASSNER (Laboratory of applied Bioorganic chemistry, Division of Life Science, graduate school of Agricultural Science, tohoku university, 1-1 Tsutsumidori-Amamaiyamachi, Aoba-ku,sendai 981 -8855, japan)(department of tohoku Univ Grad Sch Agr Sci Div Life Sci Lab Appl Bioorgan ChemAoba Ku Sendai Miyagi 9818855 Japan Bar Ilan Univ Dept Chem IL-52900 Ramat Gan Israel

Modest to high diastereoselectivites have been observed in the conjugate addition of functionalized alcohols to chiral (E)-nitroalkene 1 depending on the presence of metal catalysts at low tempertwre. The resultS indi... 详细信息

关键词： Diastereoselectivity michael addition alcohols catalysts

DETERMINANT SOLUTIONS OF THE NONAUTONOMOUS DISCRETE TODA EQUATION ASSOCIATED WITH THE DEAUTONOMIZED DISCRETE KP HIERARCHY

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Journal of Systems Science & Complexity 2010年第1期23卷 153-176页

作者： Satoshi TSUJIMOTO department of applied Mathematics and Physics Graduate School of InformaticsKyoto University

It is shown that the nonautonomous discrete Toda equation and its Backlund transformation can be derived from the reduction of the hierarchy of the discrete KP equation and the discrete two-dimensional Toda equation. Some explicit examples of the determinant solutions of the nonautonomous discrete Toda equation including the Askey-Wilson polynomial are presented. Finally we discuss the relationship between the nonautonomous discrete Toda system and the nonautonomous discrete Lotka- Volterra equation.

关键词： Askey-Wilson polynomial Darboux transformation discrete KP hierarchy nonautonomous discrete Lotka-Volterra equation nonautonomous discrete Toda equation.

Studies of Atomic Structure and Physical Properties of Metal Clusters in MgO by HREM and Nano-probe Methods

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Journal of Materials Science & Technology 1997年第4期13卷 265-270页

作者： Nobuo Tanaka (Dept. of applied Physics, school of engineering, Nagoya university, Nagoya, 464-01, japan) Dept. of applied Physics School of Engineering Nagoya University Nagoya 464-01 Japan

Nanometer-sized metal clusters were prepared inside single crystalline MgO films by vacuum co-deposition of metals and MgO. The atomic structure was studied by high-resolution electron microscopy (HREM) and nm-area electron diffraction. The size of the clusters is ranging from 1 nm to 3 nm without those larger than 5 nm, and most of them have definite epitaxial orientations with the MgO matrix films. The character of the composite films is very much useful for the studies of various kinds of physical properties with anisotroPy. The physical properties such as electric transport, magnetic, optical absorption, sintering and catalytic ones were thus measured on the same samples analyzed by HREM by using high sensitivity apparatus with interest of clarifying the retationship between the atomic structure and physical properties

关键词： Figure Nano Studies of Atomic Structure and Physical Properties of Metal Clusters in MgO by HREM and Nano-probe Methods HREM MgO

Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part I: LiMn_2O_4 and LiCo_(0.5)Ni_(0.5)O_2

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Journal of Materials Science & Technology 1999年第6期15卷 509-514页

作者： Tomoki TSUMURA and Michio INAGAKI (graduate school of engineering, Hokkaido university Kita-ku, Sapporo, 060-8628 japan) Hokkaido Univ Grad Sch Engn Kita Ku Sapporo Hokkaido 0608628 Japan

Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.

关键词： LiMn2O4 and LiCo Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part I O2 Ni

Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part Ⅱ: TiO_2, V_2O_5 and MoO_3

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Journal of Materials Science & Technology 2000年第1期16卷 5-14页

作者： Tomoki TSUMURA and Michio INAGAKI (graduate school of engineering, Hokkaido university Kita-ku, Sapporo, 060-8628, japan) graduate school of engineering Hokkaido University Kita-ku Sapporo 060-8628 Japan NARD Institute Ltd. 2 Nishinagasu Amagasaki 660-0805 Japan Aichi Institute of Technology Yakusa Toyota 470-0392 Japan

Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.

关键词： Li Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part V2O5 and MoO3