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Kazuaki Narita
1985 年 54 巻 4 号 p.
1217-1219
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
We consider a predator-prey system on a continuous rank spectrum of species. We present conjectural N-soliton solution of this system and investigate the flow of biomass caused by 1-soliton solution.
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A. Kunick, W. -H. Steeb
1985 年 54 巻 4 号 p.
1220-1223
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Two coupled dynamical systems which both behave chaotically without coupling are studied. The coupling is linear. We show that the coupled system can behave regularly.
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Atsunori Danjo, Hiroyuki Nishimura
1985 年 54 巻 4 号 p.
1224-1227
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Elastic differential cross sections (DCS’s) for H
2O have been measured in the energy range from 4 to 200 eV and in the angular range from 10° to 120° by a crossed beam method. The absolute scale of the DCS’s was given by normalizing the relative values to the absolute elastic DCS’s for He with the relative flow method. Integral and momentum transfer cross sections were derived from the DCS’s and compared with the previous experimental and theoretical results.
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Kimitaka Itoh, Sanae-Inoue Itoh
1985 年 54 巻 4 号 p.
1228-1231
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Integral of wave kinetic equation of electrostatic drift waves is obtained based on the weak turbulence approach for arbitrary number of modes, N. If the stationary spectrum of N modes exists, the wave amplitude is bounded for any initial conditions. The stationary spectrum, which appears only if the initial spectrum coinsides with it, is estimated to be the most probable one, if the amplitude of the stationary spectrum is large. In the presence of the spontaneous emission term, the spectrum relaxes to the stationary spectrum.
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Hideki Arimoto, Sadao Masamune, Akiyoshi Nagata, Kiyoshi Ogawa, Shuich ...
1985 年 54 巻 4 号 p.
1232-1235
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
The toroidally asymmetric flux enhancement (“dynamo effect”) and the axisymmetrization of the enhanced fluxes that follows in the setting up phase of Reversed Field Pinch are investigated on the STP-3(M) device. A rapid increase in the toroidal flux generated by the dynamo effect is first observed near the poloidal and toroidal current feeders. Then, this inhomogeneity of the flux propagates toroidally towards the plasma current. The axisymmetrization of the flux is attained just after the maximum of plasma current. The MHD activities decrease significantly after this axisymmetrization and the quiescent period is obtained.
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Keizo Murata, Madoka Tokumoto, Hiroyuki Anzai, Hiroshi Bando, Gunzi Sa ...
1985 年 54 巻 4 号 p.
1236-1239
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
We report the superconductivity with the onset temperature as high as 8 K in the organic conductor of β-(BEDT–TTF)
2I
3, bis-ethylenedithio otetrathiofulvalenetriiodide. The increased superconducting transition temperature was achieved by an application of a soft pressure, i.e. 1.3 kb. High value of the upper critical field,
Hc2 was observed. (
Hc2>13 kOe at 1.5 K along the
c*-axis.)
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Masashige Onoda, Hiroshi Nagasawa, Keiji Kobayashi
1985 年 54 巻 4 号 p.
1240-1243
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
We present the detailed EPR results on the single chain 1-d conductor of the ion-radical salt (TMTTF)
2ClO
4 in the temperature range between 77 K and 373 K above the anion ordering phase transition temperature. The spin susceptibility results reveal the gradual metal-to-nonmetal transition around 230 K. This gives us a clue to understand the transport properties as well as the dynamical behaviors of the electrons. The anomalous temperature dependence of the
g-factor is observed.
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Koichi Katsumata, Chiaki Uyeda, Mitsuhiro Motokawa, Muneyuki Date
1985 年 54 巻 4 号 p.
1244-1248
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Electron spin resonance experiments in pulsed high magnetic fields have been performed on the randomly mixed antiferromagnet with competing spin anisotropies, Fe
(1−x)Co
xCl
2·2H
2O. When the external field is applied along the b-axis (the easy axis of CoCl
2·2H
2O) of the mixed crystals, new resonance lines appear together with the spin-cluster resonances. We assign these new lines to Fe
2+ localized excitations in this mixed system. A quantitative agreement between the theory and the experiments is attained using only one adjustable parameter.
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Kazuaki Narita
1985 年 54 巻 4 号 p.
1249-1256
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
A method of discretization along the light-cone is applied to two-component nonlinear wave equations found by Sarker, Trullinger and Bishop and Montonen. We present a soliton solution, envelope soliton solutions and elliptic function solutions for discretized wave equations of coupled real fields, and complex envelope soliton solutions for coupled real and complex fields.
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Sadayoshi Toh, Takuji Kawahara
1985 年 54 巻 4 号 p.
1257-1269
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The stability of various equilibrium solutions of a strongly dispersive nonlinear system with instability and dissipation is investigated both numerically and analytically. Periodic trains of soliton-like pulses are found to be stable when the distance between adjacent pulses becomes smaller than a critical value. This critical value is determined by linear stability analysis. A modulational type instability is also observed for a very long string of soliton-like pulses even when the fundamental distance is within the stable regime.
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Hiromasa Hirakawa, Soichi Owa, Ken-ichi Iso
1985 年 54 巻 4 号 p.
1270-1273
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
We discuss the detection of stochastic background gravitational radiation with resonant mechanical antennas. Using a pair of antennas of the precisely same frequency, one obtains a low detection threshold for energy density of the radiation, when outputs from the phase-sensitive detectors following each antenna are directly correlated.
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Shoichi Kai, Eiji Ooishi, Masahide Imasaki
1985 年 54 巻 4 号 p.
1274-1281
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Various types of macroscopic nonlinear-waves were observed on the interface between two liquid phases, water and nitrobenzen, which contained a surfactant and an iodine respectively. These two solutes react with each other and produce precipitate. Some of macroscopic structures have been caused by a kind of the Marrangoni effect with the second order reaction. Main motions were classified into four kinds of waves, i.e. solitary, oscillatory, rotational and chaotic ones. Other submotions were also observed. The typical motions, the characteristies and the concentration phase diagram are given.
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Yasuo Tomishima
1985 年 54 巻 4 号 p.
1282-1289
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The Thomas-Fermi theory of an atom at finite temperatures is developed with the help of the temperature Green’s function. The electron density and the Helmholtz free energy density of the atom in equilibrium is expressed as a function of the self-consistent potential energy.
The inhomogeneity correction to the kinetic free energy is proved to be the same as that given by Perrot. The exchange and the correlation energy in ring diagram approximation is also incorpolated in the statistical model.
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Seishiro Hashiguchi, Mitugi Hasikuni
1985 年 54 巻 4 号 p.
1290-1298
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Values of 272 branching ratios are determined for 98 ArII levels which include 5s, 6s, 4p, 5p, 4d, 5d, 4f and 5f levels. Among them, 178 branching ratios are not given in the NBS’s table. Spectral intensities of ArII lines were measured in the wavelength range from 500 nm to 200 nm using a hollow cathode glow discharge as a light source. Values of the branching ratio agree with those obtained by Danzmann and Kock within ±5%.
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Hiroshi Miyagi, Taiichiro Haseda, Tuto Nakamura
1985 年 54 巻 4 号 p.
1299-1310
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
In cavities of simple shape inside a dielectric, the molecular attractive forces are studied in the Drude-Lorentz model of molecule, by assuming the dielectric function of the medium to be of the single-resonance type. The retardation effect is neglected in view of pores of very small size. The medium correction to the intermolecular attractive force is shown to be anisotropic but of small magnitudes, for the distance of physical interest. The potential energy of a molecule coming also from the same origin is studied in details, because it must be a basic quantity in predicting features of the phase transition of condensed matter observed in pores.
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M. A. Hossain, F. Khalil
1985 年 54 巻 4 号 p.
1311-1316
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The effects of suction and Hall currents on unsteady flow of an electrically conducting fluid past a uniformly accelerated flat porous plate imbedded in a uniform external magnetic field transverse to it is considered. It is assumed that the induced magnetic field is negligible compared to the imposed magnetic field. Series solutions for velocity and skin-friction are obtained under the assumption that the hydromagnetic parameter (
Mt) is small. The profiles for the velocity components are shown graphically with the effects of the Hall parameter m, the hydromagnetic parameter (
Mt), and the suction parameter α. The numerical values of the skin-friction components are given in tabular form for different values of the parameters.
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Hideki Takayasu
1985 年 54 巻 4 号 p.
1317-1321
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Statistical properties of a 3-wave system are investigated numerically and a comparison is made with the results calculated by approximations in turbulence theory. It is found that evolution of energy and distribution of amplitude are affected by higher order moments of initial distribution except chaotic cases. In some cases, the approximations are found to be qualitatively poor.
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Yasuhide Fukumoto
1985 年 54 巻 4 号 p.
1322-1328
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The slow motion of a small sphere between two concentric circular cylinders filled with a viscous incompressible fluid is investigated theoretically on the basis of the Stokes equation. The force experienced by the sphere translating in an arbitrary direction is determined up to the first order effect of the walls. The several different cases investigated previously are included in this study; the case of a single plane wall, the case of two parallel plane walls and the cases of the outside and inside regions of a circular cylinder. However small its radius is, the effect of the inner cylinder can not be neglected.
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Katsumi Takenouchi
1985 年 54 巻 4 号 p.
1329-1338
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The transient supersonic flow of a slightly conducting gas in an MHD channel with axial symmetry is investigated assuming that the magnetic Reynolds number and the interaction parameter are small. The solutions to the linearized equations for supersonic flow show that in the asymptotic limit as
t→∞, these solutions all tend to coincide with the solutions for the corresponding steady flow. This point is remarkably different as compared with the result for the transient subsonic flow in a channel. The reason for this discrepancy is made clear. The time for the transient flow to achieve the steady state is also evaluated.
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Masao Sugawa, Reiji Sugaya
1985 年 54 巻 4 号 p.
1339-1347
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The nonlinear interaction of linearly stable electrostatic electron cyclotron harmonic waves and electrons due to the cyclotron damping is experimentally examined. As moderate amplitude waves are excited, the amplitude oscillation of the wave and the periodic oscillation of electrons trapped by the wave are observed, whose results are explained by the monochromatic wave approximation. As large amplitude waves are excited, wave number spectra of waves widen, and then, the amplitude oscillation of waves collapses due to the many wave-particle interaction. The results can be explained qualitatively in the quasilinear theory for a weak turbulent plasma.
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Sakae Besshou, Osamu Motojima, Motoyasu Sato, Fumimichi Sano, Tokuhiro ...
1985 年 54 巻 4 号 p.
1348-1359
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Thermonuclear fusion neutron emissions of up to 3×10
9 neutrons/sec have been observed in Heliotron E deuterium plasmas. “Currentless plasmas” were produced by electron cyclotron resonance (53 GHz, 150 kW) and further heated by hydrogen neutral beam injection (2.2 MW,
H°→
D+). It is found that all observed neutron emissions have thermonuclear origin due to the absence of hard X-ray background. Agreement between neutron and charge exchange ion temperature measurements (500 eV<
Ti(0)<900 eV) has been found at intermediate densities (1.5<\bar
ne<3×10
13 cm
−3). The maximum fusion power carried by neutrons, 1.2 mW, is about 10
−9 of the absorbed neutral beam powers. The neutrons reported in this paper are the first observation of pure thermonuclear fusion neutrons in a helical heliotron plasma confinement device.
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Takashi Shimozuma, Junichi Takahashi, Hitoshi Tanaka, Takashi Maekawa, ...
1985 年 54 巻 4 号 p.
1360-1368
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
In order to reveal the physical mechanism of the plasma current start-up experiment by rf in WT-2 tokamak, a two dimensional Fokker-Planck equation, which includes quasilinear diffusion terms of electron cyclotron wave (ECW) and lower hybrid wave (LHW), particle and energy losses, is solved computationally. The calculations show the following results; In the initial electron cyclotron heating plasma, the applied vertical field
BV cancels the toroidal drift for some electrons which generate a current to produce the poloidal field and the electrons are confined in an equilibrium position. The dependence of generated currents on
BV qualitatively agrees with experimental results. Further, the electrons, which are accelerated in the perpendicular direction by ECW, are pitch-angle scattered by Coulomb collision to the parallel direction and quasilinearly interact with LHW having high phase velocity, resulting in a toroidal current start-up.
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Yasuyuki Nomura
1985 年 54 巻 4 号 p.
1369-1379
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
It is shown that the tilting motion of a compact torus can be stabilized by toroidally circulating energetic particle beams. The required beam current relevant to tilt stability is estimated to be sufficiently small compared to the plasma current if the circulation frequency of beam particles is close to the betatron frequency. As an example, this stabilizing method is applied to a field reversed configuration. Effects of the plasma surface current and beam divergences are also examined.
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Sho Ji Tanaka, Ryo Sugihara, Shuichi Takamura, Takayoshi Okuda
1985 年 54 巻 4 号 p.
1380-1386
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
For the evaluation of the velocity diffusion, a set of difference equations is derived which describes the motion of an ion in a nonuniform magnetic field under the influence of an externally excited lower hybrid wave. In addition to the well-known cyclotron harmonic resonance, the formula includes a phase shift of the wave-particle interaction. The latter, which has been missed in all previous papers, enhances the diffusion of ions in velocity space. The frequency shift due to the guiding-center drift is also included. It can govern the velocity diffusion when the particle energy is high. A numerical calculation for an example is presented to show how the velocity diffusion is enhanced.
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Iwao Hashimoto, Kouichi Niikura, Hiroyuki Yamaguchi
1985 年 54 巻 4 号 p.
1387-1393
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
Antiphase domain boundaries (APBs) formed in quenched β-brass have been investigated by transmission electron microscopy. Anomalous contrast of images has been observed in the bright fields with \bar12\bar1 and 1\bar10 fundamental reflections under a two beam condition. The image contrast of APBs is analyzed by the method of the image matching with electron micrographs computed by taking into account detailed geometrical conditions of specimens. The contrast is due to local lattice expansion at APBs. An additional displacement of the lattice across APBs has been estimated to be in the range of 0.1–0.5 Å.
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Noboru Yamada, Takashi Ozawa, Takuro Ikeda
1985 年 54 巻 4 号 p.
1394-1402
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The crystal structure of (NH
4)
2BeF
4 has been investigated at several temperatures by X-ray diffraction with particular interest to the temperature dependence of temperature factors. It is revealed that the mean-square thermal amplitudes
U33’s for F(2) and F(3) and
U22 for F(1) are not proportional to absolute temperature in the normal (N) phase. This is understood by assuming the disorder of F atoms, or of BeF
4 groups. The phase transition to the ferroelectric (F) phase is characterized by the order of BeF
4 groups.
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Tsutomu Asano
1985 年 54 巻 4 号 p.
1403-1410
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
The solid-solid phase transition of hexatriacontane was investigated by X-ray diffraction and DSC thermal analyses. The results show that the crystalline c
*-axis remains unchanged during the transition. In a high purity specimen, the original monoclinic crystal once changes to the vertical structure and then transforms to the high temperature monoclinic form, where the molecular chain changes its staggering direction by 90°. In a lower purity specimen, the original orthorhombic crystal also changes into the high temperature monoclinic form. The interlayer spacing calculated from the crystalline structure shows that the high temperature monoclinic form is advantageous for molecular rotation. The irreversibility of the solid-solid transition is due to defects in the crystal caused by the change of the staggering direction.
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Akihiko Toda, Hiroshi Kiho, Hideki Miyaji, Kenjiro Asai
1985 年 54 巻 4 号 p.
1411-1422
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The growth of polymer crystals in a dilute solution is theoretically investigated in terms of secondary nucleation and growth. Effects of the finiteness of molecular chain length and the nucleation of cilia are considered on the basis of the kinetic theory studied by Seto and Frank. The dependence of the growth rate of polyethylene single crystals on concentration and supercooling is explained as regime II growth where the growth of lower molecular weight materials (
Mw<2.5×10
4) is controlled by the nucleation of solute molecules while that of higher ones (
Mw<8×10
4) by the nucleation of cilia.
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Noritaka Kuroda, Masamichi Sakai, Yuichiro Nishina
1985 年 54 巻 4 号 p.
1423-1429
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The Raman scattering spectra in the layer compound red-HgI
2 have been measured in detail under hydrostatic pressure. Interatomic force constants are deduced from the data on the basis of a simple Born-von Kármán model to estimate the harmonic frequency of the infrared active
Eu1(TO) mode. The frequency is found to be considerably smaller than the experimental value at low pressures. This discrepancy is attributed to the shift due to the quartic anharmonicity associated with the shear potential of a Hg–I bond. Its harmonic force constant increases rapidly with increasing pressure, so that the
Eu1(TO) mode becomes rather harmonic at high pressures. The anharmonicity due to the change in crystal volume is also discussed in relation to the pressure dependence of the interlayer interaction between iodines. Our experimental results show that the effective size of iodine ions decreases with increasing pressure.
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Satoshi Tanaka, Hiroshi Yamada, Yosuke Kayanuma
1985 年 54 巻 4 号 p.
1430-1442
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The tunneling states of an impurity in off-center potentials with
Oh-symmetry is investigated. A method of solving the quantum mechanical eigenvalue problem is presented, in which the wave function is expanded in a series of the symmetrized orthonormal set of the basis functions constructed by the eigenstates of a three-dimensional harmonic oscillator. The Schrödinger equation is transformed into a secular equation for the Hamiltonian matrix and solved numerically. The method is applied to a model potential given by
V(
r)=
a(
x2+
y2+
z2)+
b(
x4+
y4+
z4)+
c(
x2y2+
y2z2+
z2x2), which covers the cases from 〈100〉-off-center minimum to 〈111〉-off-center minimum continuously by changing the parameter values. The features of the level structure are clarified in connection with the potential shape.
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Yoshihiro Ishibashi, Ikuo Suzuki
1985 年 54 巻 4 号 p.
1443-1451
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Phase diagrams of mixed crystals between a ferroelectric and an antiferroelectric crystals, both belonging to the KH
2PO
4-family, were discussed on the basis of the Slater model. The free energy function for the antiferroelectric transition was analyzed in some detail. The role of the intersublattice interaction, which is substantial for giving rise to the antiferroelectric transition, was reconsidered and it is pointed out that a ferroelectric phase with the polarization along the [110] direction may be stabilized when the interaction changes its sign. Also the role of the intrasublattice interaction is mentioned. The results are discussed in the relationship with the RbH
2PO
4-NH
4H
2PO
4 mixed crystal system.
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Kêitsiro Aizu
1985 年 54 巻 4 号 p.
1452-1457
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The concept “semicommensurate”, introduced in the paper [J. Phys. Soc. Jpn.
53 (1984) 1775], is explained again. (Abbreviations Pr, CF, IF and SF are used for a or the prototypic phase, perfectly commensurate ferroic phase, perfectly incommensurate ferroic phase and semicommensurate ferroic phase, respectively.) Although it is impossible that, on cooling, Pr is changed to SF by second-order transition earlier than to IF, it is possible that IF, which succeeds Pr, is changed to SF by second-order transition earlier than to CF by first-order transition. This possibility is accounted for, using not both the soft order parameters and a supporting hard order parameter but only the former (unlike in the preceding paper).
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Yasushi Ishii, Satoru Sugano
1985 年 54 巻 4 号 p.
1458-1468
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The thermodynamical properties of a 4-site model microcluster are investigated. It is shown that the thermal fluctuation of the structural degrees of freedom has a large amplitude so that the
melting, that is, the excitation of all the structural degrees of freedom of interests takes place easily. The large amplitude of the structural fluctuation is characteristic in a small particle because of a large portion of surface atoms which are free from the strong constraint acting on bulk atoms. On the other hand, the electronic properties at finite temperatures are very suggestive of those of a bulk solid. The effect of the quantum fluctuation on the distorted structure in the ground state is discussed in relation to the broken symmetry.
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Kazumasa Shinjo, Tomohei Sasada
1985 年 54 巻 4 号 p.
1469-1476
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
A study is made on the ground state of an ionic adlayer with repulsive long range interaction. The method for constructing commensurate structures is presented for the simplest cases of coverage. The lower bound for the ground state energy is given as a function of the coverage. The misfit between an ordered structure due to the intrinsic interaction between adatoms and the substrate structure is discussed. It is found that for the square lattice of the substrate the adlayer is frustrated over a whole range of coverage, and for the regular triangular lattice the adlayer is unfrustrated for a certain class of coverage.
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Akira Hasegawa
1985 年 54 巻 4 号 p.
1477-1485
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The electronic energy band structure for MnPt
3, FePd
3 and PtFe
3, which are a typical ferromagnetic transition metal alloy having the AuCu
3-type crystal structure, is calculated by a self-consistent, spin-polarised APW method with the local-spin-density approximation. The relativistic effects except the spin-orbit interaction are taken into account. A fairly large exchange splitting, about twice that of the Fe metal, is found to occur in the Mn and the Fe d bands of these alloys. Calculated results for the density of states and the spin magnetic moment of each constituent atom agree quantitatively well with recent experimental results.
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Norimichi Kojyo
1985 年 54 巻 4 号 p.
1486-1496
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
A new systematic cluster theory beyond the single-site coherent potential approximation is presented for averaged one-particle Green’s functions. The formalism is developed in augmented-space and illustrated for site-diagonal disorder. The theoretical feature is to treat overlapping clusters exactly by employing a kind of the matrix continued fraction. The resulting Green’s functions are analytic, translationally invariant, and predict proper limiting behaviors at weak or strong scattering and high or low concentrations. Model calculations for a static disordered chain are shown to compare well with the essentially exact calculation.
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Norimichi Kojyo
1985 年 54 巻 4 号 p.
1497-1505
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Random binary alloys with off-diagonal as well as diagonal disorder and short-range order are studied by the new cluster approximation introduced in the preceding paper. The augmented-space formalism of Kaplan and Gray is employed. The resulting one-particle Green’s functions are analytic, translationally invariant, and valid in all mean-free-path regions. Model calculations for linear chains are presented and shown to agree well with the essentially exact calculations.
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J. Ihm, J. C. Phillips
1985 年 54 巻 4 号 p.
1506-1513
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Activation energies associated with resistivity anomalies of electrons confined to a two-dimensional potential well in a high magnetic field have recently been reported by Chang
et al. and by Kawaji
et al. The unusual behavior of the activation energy is analyzed in terms of two different excitation mechanisms coexisting in the system in the presence of fluctuations in the external donor impurity potential.
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Yoshio Sakai, Nobuo Tsuda, Tamio Sakata
1985 年 54 巻 4 号 p.
1514-1518
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
A Hall coefficient and an electrical conductivity of NbO
2 were measured just below the metal-insulator transition temperature. It is concluded that the conduction is mainly a band conduction of large polarons above 550 K with an energy gap decreasing to zero toward the transition. A reflectivity measurement was consistent with the narrowing of the gap.
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Tsuneya Ando, Yoshimasa Murayama
1985 年 54 巻 4 号 p.
1519-1527
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The broadening of Landau levels is calculated in a two-dimensional electron system at a GaAs/AlGaAs heterostructure in strong magnetic fields. Scatterers are assumed to be charged ions in the AlGaAs layer and in the bulk GaAs layer. The self-consistent determination of the broadening and screening is shown to be essential and gives rise to a drastic reduction of the broadening when the spacer thickness is sufficiently large. The broadening of cyclotron resonance and the peak values of the diagonal conductivity are also calculated.
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Tsuneya Ando
1985 年 54 巻 4 号 p.
1528-1536
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
The subband structure of a two-dimensional hole system at GaAs/AlGaAs heterojunctions and quantum wells is calculated in the self-consistent Hartree approximation. The subband dispersion is shown to be quite nonparabolic and anisotropic. The cyclotron effective mass is strongly dependent on the hole concentration. The spin splitting is extremely large due to the lack of inversion symmetry at single heterojunctions. Light-scattering spectra are calculated for quantum wells and the agreement with experiments is excellent for systems with low hole concentrations.
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Takao Kohara, Masataka Yamaguchi, Kunisuke Asayama
1985 年 54 巻 4 号 p.
1537-1542
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
The hyperfine field (
Hhf) distribution and the nuclear spin-lattice relaxation time (
T1) of
61Ni in metallic Ni fine particle of 30∼800 Å in average size were measured in the temperature range 4.2 K∼0.4 K by NMR spin echo technique. Below 200 Å
Hhf has a wide distribution toward the lower field side indicating a predominant decrease of the magnetization and/or increasing of s-d mixing near the surface region of the particles.
T1 decreases rapidly with decreasing size keeping the relation of
T1T=const.
T1 increases with external field. The relaxation behavior is qualitatively exaplained by the Weger mechanism through the indirect interaction between nuclear spin and conduction electrons via the spin wave where the spin wave stiffness constant decreases with decreasing size.
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Yoshio Kitaoka, Nian-Sheng Chang, Takeo Ebisu, Masahiro Matsumura, Kun ...
1985 年 54 巻 4 号 p.
1543-1551
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Electric resistivity,
a.c. magnetic susceptibility, magnetization and
157Gd NMR measurements have been performed in (Ce
1−xGd
x)Ru
2 for
x=0.12 and 0.13. The resistivity measurement determines the superconducting transition temperature for
x=0.12 and 0.13 to be 4.85 K and 4.4 K, respectively, though both the susceptibility and magnetization show no diamagnetism. An internal field associated with the ferromagnetic order appears in
157Gd NMR, where the nuclear spin-lattice relaxation time for
x=0.12 below 100 mK shows a characteristic temperature dependence for the superconductivity. From these results, it is concluded that the compound with
x=0.12 is microscopically in a coexistent state of the superconductivity and the ferromagnetism at low temperature, forming a self-induced vortex state.
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Kazushige Machida, Tetsuo Ohmi, Masa-aki Ozaki
1985 年 54 巻 4 号 p.
1552-1559
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Based on the Ginzburg-Landau theory the angular dependence of the upper critical field
Hc2 for d-wave and p-wave superconductivity is derived for crystals with cubic and tetragonal symmetry. The anisotropy of
Hc2 can be large in some cases, depending upon the dimensionality of the irreducible representation and the number of the gradient invariant terms. It is concluded that the experiment to measure the anisotropy of
Hc2 might be a useful means to distinguish p-wave and d-wave pairing from s-wave pairing superconductivity.
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Kiichi Okuda, Satoru Noguchi, Makoto Honda, Muneyuki Date
1985 年 54 巻 4 号 p.
1560-1569
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Effect of magnetic ions on the superconductivity is investigated in the pseudo ternary compounds Pb
1.2−xEu
xMo
6S
8 by measuring the electrical resistance and magnetization in the field up to 650 kOe. The superconducting and structural transformation temperatures,
Tc and
Ts, are obtained as a function of Eu-concentration. A clear enhancement of
Hc2 defined as the onset of superconductivity is found around the composition Pb
0.7Eu
0.5Mo
6S
8 and the
Hc2(0) is estimated to be 630 kOe. The dependences of
Tc and
Hc2 on the temperature and Eu-concentration are successfully explained by the theory of Maekawa and Tachiki with the antiferromagnetic coupling of −3.2±0.6 meV between the conduction electrons and Eu-spins. Valence mixing of Eu
2+ and Eu
3+ is suggested in Eu
1.2Mo
6S
8 from the high field magnetization data.
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Setsuo Mitsuda, Yasuo Endoh
1985 年 54 巻 4 号 p.
1570-1580
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Neutron depolarization experiments investigating the magnetization processes have been performed by using pulsed polarized neutrons for the first time. Results on both quenched and annealed ferromagnets of Fe
85Cr
15 alloy indicate the significant difference in the wavelength dependence of depolarization between them. It also constitutes the experimental demonstration of the theoretical prediction of Halpern and Holstein.
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Kiyoshi Ooiwa
1985 年 54 巻 4 号 p.
1581-1591
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Magnetization measurements and NMR of
59Co were carried out to investigate the magnetic moment of a pseudobinary alloy system CoTi
1−yGa
y. A Heusler alloy Co
2TiGa (
y=0.50) shows the characteristics of an itinerant electron ferromagnet which are the small magnitude of magnetic moment of 0.40 μ
B/Co, the linear behaviour in σ
02−
T2 plot and
pc⁄
ps=2.1. This alloy system shows ferromagnetic behaviour in the composition range 0.30<
y<0.70. The coexistence of ferromagnetic and paramagnetic Co were observed by NMR in the composition range 0.50<
y≤70. Spontaneous magnetization shows maximum at
y=0.45 and the existence of another Co with 0.56 μ
B was made clear by NMR of
59Co and magnetization measurements. The experimental results are well explained from the view of a local environment effect.
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Yoshinori Takahashi, Tôru Moriya
1985 年 54 巻 4 号 p.
1592-1598
発行日: 1985/04/15
公開日: 2007/06/01
ジャーナル
認証あり
Curie temperatures, nuclear spin relaxation rates, and temperature dependence of the magnetic susceptibilities in typical weak itinerant ferromagnets are quantitatively estimated by using the self-consistent renormalization theory of spin fluctuations and the parameter values deduced from experimental data and are compared with observations.
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Toshinobu Tsuda, Masayuki Itoh, Hiroshi Yasuoka
1985 年 54 巻 4 号 p.
1599-1609
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
The
51V and
133Cs NMR study has been performed in order to obtain the information on the spin state of a single crystal of CsVCl
3. In the ordered state the
51V NMR signal was observed around 106.5 MHz at 4.2 K and at zero external field. From this the spin reduction associated with the V
2+ ions was estimated to be 71%. The observed external field dependence of the
51V spectrum could not be explained from the simple 120° Néel model proposed by the neutron diffraction experiment. In the paramagnetic state, the quadrupole split resonance lines of the
133Cs signals were observed, which were broadened into a spectrum characteristic of the two-dimensional powder pattern in the ordered state. The spectrum could be reproduced by a modified 120° Néel structure.
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Isao Minagawa
1985 年 54 巻 4 号 p.
1610-1614
発行日: 1985/04/15
公開日: 2007/05/29
ジャーナル
認証あり
A study of phase transition of ice Ic is made by Takagi’s method, where twenty five order parameters and a unit cell comprising eight molecules are used and energies of interaction between molecules are considered. The free energy is minimized with respect to these parameters by the simplex method. When the interaction-energy parameter is positive, the ordered phase is ferroelectric and a minimum unit cell has two molecules. When it is negative, the ordered phase is antiferroelectric and a minimum unit cell has four molecules. In this phase, the direction of dipoles on one sublattice of the diamond structure is normal to that of the dipoles on the other sublattice.
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