Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 60, Issue 8
Displaying 1-50 of 52 articles from this issue
  • Hiroyuki Nagashima
    1991 Volume 60 Issue 8 Pages 2485-2488
    Published: August 15, 1991
    Released on J-STAGE: June 01, 2007
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    Numerical studies of the Rössler oscillators coupled by diffusion were carried out. It is found that a stable target pattern of incoming waves emerges from a pacemaker whose frequency is lower than that of the surrounding oscillators. For another kind of pacemaker, more diffusive target patterns are observed. The stability of the patterns was checked by imposing nonsymmetrical boundary conditions.
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  • Toshiya Takami
    1991 Volume 60 Issue 8 Pages 2489-2491
    Published: August 15, 1991
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    We calculate the parametric motion of the eigenvalues for a stadium billiard. Using the result, we present the curvature distribution introduced by Gaspard et al. We show that the tail of the distribution (the histogram for large values of the curvature K) behaves like |K|−3 in agreement with their prediction based on the GCM level dynamics. This is the first report on the tail behavior of the curvature distribution for a deterministic system.
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  • Hisao Hayakawa
    1991 Volume 60 Issue 8 Pages 2492-2495
    Published: August 15, 1991
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    The two-dimensional ordering dynamics undergoing a first-order phase transition in a system with quenched impurities is studied using a cell-dynamics method. Our numerical simulation suggests that the characteristic length l(t) obeys logarithmic laws as l(t)∼log t in the middle stage and l(t)∼(log t)4 in the late stage of ordering processes.
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  • Yoshimitsu Amagishi, Yoshishige Yoshikawa, Junji Ohara
    1991 Volume 60 Issue 8 Pages 2496-2499
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    An experiment is described where a magnetic field destabilizes the laminar shear flow of a rotating layer of mercury. When the basic motion is two-dimensional, the vortex structure due to the Kelvin-Helmholtz instability appears in a discontinuous velocity field, but for the more rapid rotation, three-dimensional destabilization of the whole liquid occurs, forming a spiral structure.
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  • Akira Yoshizawa, Nobumitsu Yokoi
    1991 Volume 60 Issue 8 Pages 2500-2504
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    Turbulent flows subject to the Coriolis force are examined theoretically to study the vortex dynamo or generation of large-scale turbulent structures. A major term in the turbulent vortex-motive force that plays a key role in the mean vorticity equation is shown to be proportional to the angular velocity vector of a rotating system with the proportional coefficient expressed in terms of the helicity. This result shows that the vortical structure with its axis in the zonal direction near the equator is a promising candidate of Saturn’s large atmospheric structures called white spots. Formation of the vortex with its axis normal to the spherical surface, as in typhoons, is also discussed.
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  • Sanae-I. Itoh, Heiji Sanuki, Kimitaka Itoh
    1991 Volume 60 Issue 8 Pages 2505-2509
    Published: August 15, 1991
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    Effect of inhomogeneity of radial electric field on drift wave instabilities is investigated. Curvature of static potential gives rise to an additional Landau resonance. Critical conditions for the stability due to sheared E×B motion of ions are estimated for various modes. Effect on anomalous transport coefficient is also discussed.
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  • Hitoshi Hojo, Tadatsugu Hatori
    1991 Volume 60 Issue 8 Pages 2510-2513
    Published: August 15, 1991
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    Radial transport induced by rotating RF fields in a magnetic mirror is studied. The RF frequency used is in the ion cyclotron range of frequency and is comparable to the electron bounce frequency. The radial particle fluxes for ions and electrons are obtained by use of the gyrokinetic equation. With a positive azimuthal mode number of the RF field, the radial particle flux is outward for Maxwellian ions and inward for Maxwellian electrons. This shows that the intrinsic ambipolarity is broken in this RF-induced transport. The present analyses can be applied to the thermal-barrier pumping of a tandem mirror.
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  • Yosikazu Isikawa, Katsunori Mori, Yoshiaki Ogiso, Kazunori Oyabe, Kiyo ...
    1991 Volume 60 Issue 8 Pages 2514-2517
    Published: August 15, 1991
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    The thermal conductivity of CeNiSn single crystals has been measured in the temperature range between 1.6 K and 18 K along each of the principal axes. The thermal conductivity is very anisotropic, reflecting the orthorhombic crystal structure. A broad peak and an obscure indent are observed at 5.6 K and 6.9 K, respectively, in the temperature dependence of the thermal conductivity along the b-axis. This anomalous behavior is considered to be associated with the energy-gap formation in the semiconductorlike heavy-fermion compound around these temperatures. Below 2.6 K, all of the thermal conductivity along the a-, b- and c-axes obeys a T1.5-dependence. Carriers of the thermal conduction are mainly phonons and are scattered dominantly by electrons, which is speculated from the comparison with the electrical resistivity and specific heat data.
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  • Yahachi Saito, Kazuyoshi Kurosawa, Hisanori Shinohara, Susumu Saito, A ...
    1991 Volume 60 Issue 8 Pages 2518-2521
    Published: August 15, 1991
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    Carbon K-emission spectra of solid C60 have been obtained by electron beam excitation. The spectra show nine distinct features over the K-emission band from 284 to ∼260 eV. These features are compared with the density of states of C60 calculated under the local-density approximation in the density-functional theory. Good agreement between the experimental spectrum and the calculated one is found.
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  • Junji Sakurai, Masahiro Horie, Satoru Araki, Hidefumi Yamamoto, Teruya ...
    1991 Volume 60 Issue 8 Pages 2522-2525
    Published: August 15, 1991
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    We measured the thermopower under magnetic field (magneto-thermopower) on artificial metallic mutilayers, Fe/Cr and Cu/Co/Cu/Ni(Fe), which have been reported to show the giant magnetoresistance. The magneto-thermopower for these samples was also found to be remarkably large, corresponding to their giant magnetoresistance. The magneto-thermopower on Fe/Cr multilayers was observed to change its sign with temperature variation.
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  • Hideaki Fujitani, Setsuro Asano
    1991 Volume 60 Issue 8 Pages 2526-2529
    Published: August 15, 1991
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    The electronic structure of the NiSi2/Si(001) interface was studied using LMTO-ASA (linear muffin-tin orbitals in the atomic sphere approximation) based on the density functional formalism. We examined two interface structures in which the Ni atoms at the interface are sixfold-coordinated or eightfold-coordinated. The sixfold structure had a negative Schottky barrier height (EfEv). The eightfold NiSi2/Si(001) structure showed almost the same Schottky barrier height as the Type-A NiSi2/Si(111) interface despite the difference in the interface atomic structure.
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  • Yoshishige Uchida, Yasushi Kanke, Eiji Takayama-Muromachi, Katsuo Kato
    1991 Volume 60 Issue 8 Pages 2530-2533
    Published: August 15, 1991
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    Magnetic properties and electrical resistivity of NaV6O11 single crystal have been investigated. Magnetic transition was observed at 64.2 K. This oxide having a hexagonal crystal structure exhibited a uniaxial magnetic anisotropy with the easy axis of magnetization parallel to [001]. The spontaneous magnetization at 5 K was 1.7 μB per formula unit. The resistivity perpendicular to [001] showed an anomaly at the Curie temperature similar to that of ferromagnetic metals, while that parallel to [001] showed no such anomaly. This behavior suggests the itinerant character of d electrons.
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  • Y\={u}ichi Tazuke, Kazunobu Kuwazawa, Yasusi Onishi, Toshikazu Hashimo ...
    1991 Volume 60 Issue 8 Pages 2534-2537
    Published: August 15, 1991
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    Magnetic susceptibility and electrical resistivity were measured on polycrystalline samples of random intercalation compounds of CuxTiS2 with 0<x<0.3. Single-phase samples with 1T structures were prepared for 0<x≤0.2. In 4.2 K≤T≤300 K, the samples showed paramagnetic behavior with small temperature dependence, suggesting itinerant electron magnetism. The resistivity is described by a constant term plus a Tm one. The exponent m takes values of between 1 and 2, contrary to the previous result. This result suggests that the scattering is not dominated by the usual electron-phonon scattering only.
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  • Kazuyoshi Takeda, Kensuke Konishi, Hiroyuki Deguchi, Nobuo Iwata, Toru ...
    1991 Volume 60 Issue 8 Pages 2538-2541
    Published: August 15, 1991
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    In the commensurate phases with the wave vector k(0, 0, k) for k=13⁄14 and k=7⁄9 in the intermetallic rare earth compound PrCo2Si2, paramagnetic ions with individual entropy kBln2 have been found to be immersed regularly by the direct analysis of the observed heat capacity in zero external magnetic field. The possibility of phase slipping of the sinusoidal exchange field has also been discussed as driven by the variation of temperature in zero field.
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  • Mitsuo Kasaya, Tomofune Tani, Hiroyuki Suzuki, Kenji Ohoyama, Masahumi ...
    1991 Volume 60 Issue 8 Pages 2542-2545
    Published: August 15, 1991
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    Experimental results of magnetization and neutron diffraction measurements on single-crystal CePdSn revealed that the 4f electrons in CePdSn are in a localized Ce3+ state, and the magnetic structure below TN=7 K is incommensurate with the propagation vector of q=(0, 0.473, 0). Nickel substitution for Pd strengthens the Kondo effect, resulting in the decrease of TN and the nonmagnetic ground state of 4f electrons in CeNiSn.
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  • Kenichi Kojima, Yutaka Hukuda, Shunichi Miyata, Toshiro Takabatake, Hi ...
    1991 Volume 60 Issue 8 Pages 2546-2549
    Published: August 15, 1991
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    The 119Sn Knight shift K and nuclear spin-lattice relaxation time T1 in a heavy fermion compound U3Ni3Sn4 have been measured between 1.5 and 270 K. The K vs the susceptibility plot is linear and yields a hyperfine field of 53.2 kOe/μB. The nuclear relaxation rate due to U 5f moments (1⁄T1)f decreases markedly below about 20 K and is proportional to temperature below about 4 K, where the system is in the Fermi liquid state. The relaxation rate of 5f moments obtained from (1⁄T1)f increases linearly with temperature above about 120 K, indicating that the Korringa mechanism is dominant in the fluctuation of localized 5f moments.
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  • Masashige Onoda, Takashi Naka, Hiroshi Nagasawa
    1991 Volume 60 Issue 8 Pages 2550-2553
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    The phase transition and the spin dynamics in a triangular lattice compound LiVO2 have been studied through magnetic susceptibility and NMR measurements. It has been found that the quadrupole effect and the anisotropy of the Knight shift of the 51V nuclei are appreciably induced due to the distortion of the local symmetry at the V ions below the nonmagnetic-magnetic transition temperatures which are about 500 K on heating and 440 K on cooling. The electronic state and the spin dynamics of V ions above the transition have been explained by the localized spin model with the spin number S=1. It has also been suggested that the dynamics from the transition to about 140 K may be described by the thermally excited spin whose ground state is possibly spin-singlet due to the trimerization of V3+ ions.
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  • Yasuji Kashiwase, Motokazu Kogiso, Masahiro Mori, Masayuki Minoura, Te ...
    1991 Volume 60 Issue 8 Pages 2554-2557
    Published: August 15, 1991
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    Intensity increase in inelastic background near the 022 and 133 reciprocal-lattice points is observed, when the 022 Bragg reflection is excited in an absorbing nearly perfect germanium crystal. The experiment is performed with a double-crystal diffractometer and synchrotron radiation of wavelength 1.540 Å monochromatized and collimated with a grooved silicon crystal. The increase in the inelastic intensity can be explained to be due to the increased thermal diffuse scattering and Compton scattering caused by the incident wave transmitting deeply into the crystal with an anomalously low absorption.
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  • Tetsuo Deguchi, Yasuhiro Akutsu
    1991 Volume 60 Issue 8 Pages 2559-2570
    Published: August 15, 1991
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    We present formulae for matrix elements of a new hierarchy of multivariable colored braid matrices with Zn graded symmetry. We point out that a condition of roots of unity is necessary for the colored matrices to satisfy the colored braid relation (the colored Yang-Baxter relation). We give a general formula for the colored braid matrix elements which generalizes the colored Zn graded hirearchy and the fusion hierarchy.
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  • Takashi Nagatani
    1991 Volume 60 Issue 8 Pages 2571-2575
    Published: August 15, 1991
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    A sandpile model on a branching Koch curve is presented to study the self-organized criticality. The model is defined as a variant of the Bak, Tang and Wiesenfeld model on a branching Koch curve with a preferred direction. The avalanch process is exactly solved on the lattice. The temporal evolution of avalanches is shown to occur self-similarly. It is found that the distribution function of event magnitudes I shows exactly the scaling behavior of “1⁄I”. It is also shown that the distribution function Ns of size s of avalanches scales as Nss−log6⁄log2.
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  • Kazuyuki Tanaka, Tsuyoshi Horiguchi, Tohru Morita
    1991 Volume 60 Issue 8 Pages 2576-2587
    Published: August 15, 1991
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    The spin-pair correlation functions in the Ising model on the square lattice are obtained in three approximations of the simplified cluster variation method. We find good estimates of the critical exponents ην, γ and ν, by applying the coherent-anomaly method to the obtained spin-pair correlation functions.
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  • Noboru Hashimoto
    1991 Volume 60 Issue 8 Pages 2588-2593
    Published: August 15, 1991
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    We show that in quark jet model various multiplicities in hadron and lepton induced reactions are directly related to e+e multiplicity. In these relations only adjustable parameter is the inelasticity parameter η, which expresses the leading nucleon effect. We tested these multiplicity relations, using the data on the average multiplicities of nondiffractive pp and πp, νp and \barνp interactions and those of e+e-annihilations. The data seem to satisfy these relations at high energies.
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  • Hidekazu Kumagai, Seiichiro Nakabayashi, Sadamu Yamagata, Shohei Isomu ...
    1991 Volume 60 Issue 8 Pages 2594-2601
    Published: August 15, 1991
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    Neutron emissions from electrolysis of D2O with palladium and palladium-titanium electrodes as well as from pressurized D2 gas with titanium alloys have been measured. The neutron detector system was so designed to have very low background condition. Neutron-γ separation technique using liquid scintillator was applied to obtain essentially no γ ray background condition for neutron counting. Special care was taken to stabilize the detection system using event-by-event data recording. No significant signal of neutron emission was observed. Upper limits of emission probability of neutron have been determined to be 6×10−3 s−1, 1×10−2 s−1, and 2.3×10−2 s−1 for Pd electrode, Pd–Ti electrode, and pressurized gas systems. These values are orders of magnitude lower than that presented by Jones paper (0.4 s−1).
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  • Masanori Takaoka
    1991 Volume 60 Issue 8 Pages 2602-2612
    Published: August 15, 1991
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    Superimposed a time-dependent irrotational straining flow, a class of exact solutions to the 3-D incompressible Navier-Stokes equation is slightly generalized, which represents time-evolution of various configurations of straight jets. In particular, since the vorticity depends on two spatial variables, two-dimensional aspects of the dynamics and strain effects to the vortex structure, such as vortex reconnection, can be investigated with these solutions. The time developments of circulation, energy and enstrophy are also examined and compared with numerical results of turbulence.
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  • Shigeo Sasaki
    1991 Volume 60 Issue 8 Pages 2613-2618
    Published: August 15, 1991
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    Experimental results of drag reduction using microgel type and linear type of Napolyacrylate are described. The microgel type showed no drag reduction effects and suppressed the drag reduction effects of the linear type. This indicates that elastic components in the fluid dose not necessarily have the drag reduction effect. Dependencies of drag reduction effect of the linear type on salt concentration and pH indicated that more extended conformation of polymer induces more drag reduction effect.
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  • S. Krishan
    1991 Volume 60 Issue 8 Pages 2619-2626
    Published: August 15, 1991
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    The dynamics of a single species plasma in a rigid body rotational equilibrium undergoing expansion and contraction along the external magnetic field is investigated. It is found that under certain situations the density and the temperature can increase by many orders of magnitude.
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  • Azusa Fukano, Yasuhiko Sentoku, Masatada Ogasawara
    1991 Volume 60 Issue 8 Pages 2627-2631
    Published: August 15, 1991
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    Influence of a two-stream instability induced by a uniform ion beam propagating in a background plasma on the electron return current is investigated theoretically. The two-stream instability is taken into account with use of quasilinear equation for the plasma electron. Although the quasilinear wave-particle interaction has an effect of accelerating electrons, the electron current does not exceed the beam current. This is a result of rapid response of the electrons trying to induce an electric field that cancels the effect of quasilinear acceleration of the electrons. Analysis is valid in the initial stage of the instability.
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  • Naoyuki Amemiya, Akihito Hayakawa, Makoto Katsurai
    1991 Volume 60 Issue 8 Pages 2632-2644
    Published: August 15, 1991
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    Free-boundary flux-core spheromaks are stably produced in the external magnetic field in the TS-3 facility. In the first experiment, a z-θ-discharge is initiated with the reversed bias magnetic field, and the axial current is supplied to amplify the magnetic flux. The flux-core spheromak can be sustained by this axial current. Its lifetime is about 120 μs. In the second experiment, only by the axial current, the flux-core spheromak is successfully produced in the reversed bias magnetic field. Its lifetime is larger than 100 μs. The force-free parameter μ is estimated. It is almost time invariant, while the discharge current is changing sinusoidally. It is 11 m−1 in the first experiment and 12.6 m−1 in the second experiment, and is smaller than the eigenvalue of the spheromak with no external magnetic flux.
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  • Takayasu Tanaka
    1991 Volume 60 Issue 8 Pages 2645-2654
    Published: August 15, 1991
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    Starting from a kind of general kinetic equations for the electric potentials of waves, the Manley-Rowe relations in the nonlinear energy transport phenomena among waves in plasmas are rigorously studied. It is found that, contrary to our anticipation, the relations do not rigorously hold in general due to the presence of the wave-particle interaction process of virtual wave and instead new relations hold, which are modified in the form that also the frequency shifts of waves due to the nonlinear process are concerned. But, only for special cases, including the case of wave-wave interaction only, the relations reduce to the traditional Manley-Rowe relation. Also a new kind of general relations are found on the nonlinear frequency shifts of waves. They are of similar forms to the modified Manley-Rowe relations and complement them.
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  • Md. Mortuza Ali, Kazuo Minami, Satomi Amano, Kazuo Ogura, Tsuguhiro Wa ...
    1991 Volume 60 Issue 8 Pages 2655-2664
    Published: August 15, 1991
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    The linear theory of electromagnetic radiation from a localized plasma-loaded backward wave oscillator with sinusoidally corrugated slow wave structure driven by an annular intense relativistic electron beam has been derived and analyzed numerically. The enhanched radiation from a plasma-loaded structure is attributed to the increase in the spatial growth rate of the absolute instability. The backward wave oscillator instability without plasma is found to be most effective in a case where the beam travels near the wall of the slow wave structure. For the given number of plasma particles per unit length of the structure, the decrease in the plasma column radius enhances the output radiation.
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  • Akira Tsushima, Noriyoshi Sato
    1991 Volume 60 Issue 8 Pages 2665-2672
    Published: August 15, 1991
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    A radial potential profile is successfully changed flom hill- to well-shaped by biasing segmented endplates in a strongly magnetized plasma produced by the electron-cyclotron-resonance. The potential profile is settled down to hold the condition where there is no net electric current to the wall surrounding the plasma. There appears a radial electric current due to the non-ambipolar radial ion loss, balanced with an axial electron current determined by the sheath potential drop in front of the endplates. The radial ion loss is observed to be remarkably enhanced by increasing the outward radial electric field.
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  • Yasuhiro Ono, Noboru Yamada, Tomoyuki Hikita
    1991 Volume 60 Issue 8 Pages 2673-2677
    Published: August 15, 1991
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    Crystal structure of glassy K0.78(NH4)0.22H2PO4 is analysed using the Rietveld method in the temperature range from 20 K to 250 K. The lattice constant c shows an anomalous reduction between 120 K and 150 K, where the NH4 freezing occurs. Anomalous structure changes found at 100 K probably arise from the formation of the asymmetric hydrogen bonds without a long-range order.
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  • Yoshiyuki Shirakawa, Masatoshi Saito, Shigeru Tamaki, Masanori Inui, S ...
    1991 Volume 60 Issue 8 Pages 2678-2683
    Published: August 15, 1991
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    The structures of molten CuCl, CuBr and CuI have been measured at two temperatures, using the neutron diffraction.
    The structure factors of molten CuI and CuBr show a distinct prepeak at about 0.9 Å−1. These peaks may be caused by a kind of chemical ordering effect. The information of partial structures are estimated from the total pair distribution functions and the total radial distribution functions using the Davidon-Fletcher-Powell method. In molten CuCl, the first peak positions of the partial distribution functions agreed with those obtained by the isotope enrichment method.
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  • Naoyoshi Morita, Hideyuki Nakayama, Kikujiro Ishii
    1991 Volume 60 Issue 8 Pages 2684-2690
    Published: August 15, 1991
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    Anisotropy and temperature dependence of elastic constants of phenothiazine crystal, which undergoes a ferroelastic phase transition at Tc=248.8 K, were obtained by ultrasonic velocity measurements. The characteristic anisotropy of this crystal against shear stress is suggested to have a relation to weak intermolecular hydrogen bonds extended along b-axis. A phenomenological analysis of free energy of the crystal indicates that the novel temperature dependence exhibited by the elastic constant C33 arises from a coupling of the strain e3 with the strain e5 along which a softening is observed as the temperature approaches Tc. Temperature dependence of the spontaneous deformation in the low-temperature phase and the entropy of transition are qualitatively explained in terms of the above analysis.
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  • Shin-ichi Furusawa, Osamu Chikagawa, Shoji Tange, Takeo Ishidate, Hiro ...
    1991 Volume 60 Issue 8 Pages 2691-2693
    Published: August 15, 1991
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    Second harmonic generation (SHG) has been studied in lithium diborate (Li2B4O7) single crystal from room temperature up to the melting temperature. The magnitudes of the SHG coefficients d33 and d31, at room temperature are, respectively, 3.1 and 0.4 relative to d11 of quartz. The decrease of the SHG signal in the high temperature range suggests the possibility of the phase transition to a nonpolar phase.
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  • Tosizumi Aoki
    1991 Volume 60 Issue 8 Pages 2694-2699
    Published: August 15, 1991
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    The estimation of condensate fraction in the hard-sphere Bose system is attemped in the scheme of the Quantum Lattice Model (QLM). It is emphasized that the operators aJ and aJ which denote the creation and annihilation of atom, respectively are restricted by the anticommutation relation aJaJ+aJaJ=1 in the QLM. This describes the strong atomic correlation in the meaning that the double occupancy of atoms is removed at each lattice point. On the basis of the quasiparticle picture derived from the linearized equations of motion for the operators, the condensate fraction is calculated from the above local constraint. The obtained density dependence of condensate fraction and freezing density are in fair agreement with the numerical results.
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  • Takashi Nagatani
    1991 Volume 60 Issue 8 Pages 2700-2705
    Published: August 15, 1991
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    Pattern formation is investigated in the modified Laplacian growth model with the third boundary condition under shear flow. The modified Laplacian growth model is simulated by the diffusion-limited aggregation (DLA) with both sticking probability and drift. Morphological changes of DLA under shear flow are studied by computer simulation. The shear flow has an important effect on morphology of the deposit. It is found that the deposit leads to the formation of a characteristic needle morphology, the needle inclines to shear flow, and the width of the needle increases with decreasing sticking probability.
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  • Yukio Okwamoto
    1991 Volume 60 Issue 8 Pages 2706-2709
    Published: August 15, 1991
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    The W(001) surface with adsorbed hydrogen is studied at low coverages near the reconstruction transition temperature on the basis of the theoretical model proposed by Lau and Ying. It is shown in the mean field approximation that a narrow coexistence region appears between the two reconstructed surface phases at the directional switching transition (c(2×2)⟨11⟩→c(2×2)⟨10⟩). An effect of thermal fluctuation is qualitatively discussed.
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  • Chikara Sugiura
    1991 Volume 60 Issue 8 Pages 2710-2717
    Published: August 15, 1991
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    The fluorine Kα emission spectra in fluorescence from a series of 3d transition-metal difluorides MF2 (M=Mn, Fe, Co, Ni, Cu and Zn) have been measured with a high-resolution two-crystal vacuum spectrometer. It is shown that the observed FWHM of the Kα1,2 emission band is closely related to the difference in the electronegativity between the metal and fluorine atoms. The measured emission spectra are presented along with the UPS or XPS spectra of the valence bands and the fluorine K absorption spectra of the metal difluorides, reported previously. The structures at the fluorine K absorption edges are interpreted in terms of a molecular orbital (MO) model.
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  • Hisatomo Harima, Akira Yanase
    1991 Volume 60 Issue 8 Pages 2718-2723
    Published: August 15, 1991
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    We report the band structure calculation and Fermi surface of LaGa2 using an APW method within the local density approximation to clarify the Fermi surface property. Calculated extremal areas of the three hole Fermi surfaces explain the origin of the de Haas-van Alphen measurements.
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  • Satoshi Fujimoto, Hiroshi Kohno, Kosaku Yamada
    1991 Volume 60 Issue 8 Pages 2724-2728
    Published: August 15, 1991
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    The temperature (T) dependence of the resistivity due to the electron-electron scattering in two-dimensional Fermi systems is discussed. First, we consider an isotropic Fermi system. It is shown that the resistivity is proportional to T2, if 4kF is larger than the smallest absolute value of the reciprocal lattice vectors, though the T-dependence of the damping is T2 ln T. Next, we consider the Hubbard model. In the half-filled case, the resistivity is proportional to T ln T. The logarithmic correction is due to van Hove singularity. In the nearly half-filled case, it is pointed out that the main T-dependence of the resistivity is not T, but T2, and that the discussion on the T-dependence of the resistivity in the nested Fermi-liquid presented recently by Virosztek and Ruvalds is misleading.
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  • Haruhiko Kubo, Masaki Goda
    1991 Volume 60 Issue 8 Pages 2729-2739
    Published: August 15, 1991
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    An ensemble consisting of equal-sized samples which are cut from a both-infinite Fibonacci lattice is studied. Using the ensemble and the Landauer formula, the sample-averaged resistance and the variance are calculated numerically as a function of sample size at the band center of a tight-binding off-diagonal Fibonacci model. The characteristic power exponents, which are found in the sample-size dependence of the sample-averaged quantities, are derived analytically.
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  • Masatoshi Imada
    1991 Volume 60 Issue 8 Pages 2740-2747
    Published: August 15, 1991
    Released on J-STAGE: June 01, 2007
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    Superconducting correlation of the Hubbard model on a square lattice is reinvestigated by quantum Monte Carlo method. Results from more than one order of magnitude larger Monte Carlo steps than before are presented to discuss the convergence of the data to the ground state. By examining the dependence on the choice of initial trial states as well as on the Trotter number in detail, the superconducting correlation in the ground state is reliably obtained up to 12×12 lattice away from the half-filling and up to 16×16 lattice at the half-filling, which substantially improve former results near the half-filling. Various channels of pairing in the ground state show no system size dependence and remain quite short ranged at any filling including the region close to the half-filling. Numerical data show further evidence that neither extended s- nor d-wave superconducting state is possible in the two-dimensional Hubbard model.
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  • Kosai Tanabe, Masako Kuramoto
    1991 Volume 60 Issue 8 Pages 2748-2760
    Published: August 15, 1991
    Released on J-STAGE: June 01, 2007
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    To describe high-Tc superconductivity the hole-occupation number-constrained BCS equation is self-consistently solved for the quasi-2D bond-asymmetric two-band model with weak coupling pairing interaction. The model is characterized by the splitted two oxygen bands and hole transfer interactions among nearest and next nearest neighbour O-sites. Since the self-consistent mean field induced by the Coulomb repulsion in the O-site is dependent on the hole-occupation numbers in the oxygen site O(a) (O(b)), na (nb), behaviour of the square-root singularities in the state density is determined by the total hole-occupation number, x=na+nb. The self-consistent solution to the extended BCS equation describes x-dependence of physical properties and shows substantial quenching of the isotope effect in association with the superconducting phase realized only in a limited range of x. These results are displayed for some typical sets of interaction strengths.
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  • Hiroshi Yoshie, Shiro Ozasa, Masayuki Shiga, Yoji Nakamura
    1991 Volume 60 Issue 8 Pages 2761-2763
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    The nuclear magnetic resonance of 59Co nuclei in magnetic domains of ErCo5 has been measured under external fields up to 50 kOe at 4.2 K. To assign the observed NMR signals to each Co site, the 59Co nuclear magnetic resonance of Er(Co1−xNix)5 has also been measured under the same condition to the above.
    From the NMR study of ErCo5, we have found that the cobalt hyperfine field at the 2c site has the positive sign in contrast to the negative sign at the 3g site. This suggests that the cobalt atoms at the 2c sites in ErCo5 have large orbital moment.
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  • Shin-ichi Kondo, Takaki Itoh, Tadaaki Saito, Mamoru Mekata
    1991 Volume 60 Issue 8 Pages 2764-2767
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    High quality amorphous films of TlBr which are completely transparent below the absorption edge were obtained by the deposition of the substance onto cold substrates kept at 77 K. The films shows a sharp crystallization behavior upon heating in a small temperature range, less than 1.5 K near 95 K for a film about 1700 Å thick. The as-crystallized films just above the crystallization temperatures have microcrystalline nature characterized by the absence of the first exciton band; the exciton band grows at higher temperatures.
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  • Ken-ichi Mizuno, Mitsuhiro Furukawa, Atsuo Matsui
    1991 Volume 60 Issue 8 Pages 2768-2777
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    Absorption and luminescence spectra of phenanthrene have been investigated under pressures up to 2.4 GPa, using a diamond anvil cell. Free-exciton luminescence which is observable at ambient pressure is replaced by self-trapped-exciton luminescence at pressures higher than 1.8 GPa. From this fact it is suggested that the exciton-phonon coupling constant g increases with increasing pressure. The self-trap depth at high pressures is estimated to be ≅350 cm−1. The molecular conformation of self-trapped excitons under pressure is briefly discussed.
    In conjunction with optical spectra under pressure, spectra at ambient pressure are also discussed. The luminescence originates from the lowest singlet states 1Au and 1Bu at room temperature but at low temperatures luminescence originates from a state which is located below the 1Bu state.
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  • Howard See, Masao Doi
    1991 Volume 60 Issue 8 Pages 2778-2782
    Published: August 15, 1991
    Released on J-STAGE: May 29, 2007
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    We study the aggregation kinetics of Electro-Rheological Fluid particles which interact through dipoles induced by an external electric field and experience negligible thermal motion. For a system in d-dimensions, our theoretical calculations show that the average cluster size sav increases with time t as savtd⁄(d+3). This result shows good agreement with experiments in 3 dimensions, and with computer simulations in 2 dimensions. It also shows good qualitative agreement with the dynamic scaling theory of the cluster-cluster aggregation model.
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  • Hitoshi Hirashima, Kunitsugu Soda
    1991 Volume 60 Issue 8 Pages 2783-2790
    Published: August 15, 1991
    Released on J-STAGE: June 01, 2007
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    Using atomic transfer parameters of the constituent atoms of amino acids previously determined from an analysis of transfer free energy data for sixteen uncharged amino-acid derivatives and recently reported values of partial charges for related molecules, octanol/water transfer free energies have been estimated for derivatives of four ionic amino acids of Asp, Glu, Lys and Arg. For any of them, the calculated transfer free energy was found to be several kcal/mol lower than the experimental one determined by Fauchere and Pliska. Possible sources of this discrepancy are fully examined. It is concluded that, at neutral pH, the acidic and basic amino-acid derivatives dissolve in the octanol phase mostly (Asp, Glu, and Arg) or partially (Lys) in their charged form, as described by Yunger and Cramer (Mol. Pharmacol. 20 (1981) 602).
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  • Masayoshi Tajiri, Youichi Murakami
    1991 Volume 60 Issue 8 Pages 2791-2792
    Published: August 15, 1991
    Released on J-STAGE: June 01, 2007
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