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Kazunari Hori
1993 Volume 62 Issue 6 Pages
1819-1822
Published: June 15, 1993
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A wavelet analysis is made for one-dimensional anharmonic self-localized modes by decomposition of their time evolution signals. For a localized mode with eigenfrequency above the top of the harmonic frequency band, the finest-resolution wavelet coefficients are sufficient for analysis of the position of the center point of the mode, and the degree of mode localization.
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Toshiya Ohtsuki
1993 Volume 62 Issue 6 Pages
1823-1825
Published: June 15, 1993
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Scaling behavior of diffusion-controlled recombination with a source,
A+
A→0 and 0→
A, is investigated on the basis of a field-theoretical renormalization group technique and an associated scaling theory. The renormalization is performed exactly to all orders in perturbation and a rigorous scaling relation is derived. It becomes evident that at
d<
dc=2, steady-state density ρ
∞ depends nonclassically on a production rate
kp and a recombination rate
kr as ρ
∞∝
kpd⁄(2+d)kr−2⁄(2+d). The scaling analysis shows that the relaxation rate γ toward the steady state also exhibits nonclassical behavior, γ∝(
kpkr)
2⁄(2+d).
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Yoshiaki Itoh
1993 Volume 62 Issue 6 Pages
1826-1828
Published: June 15, 1993
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A stochastic model is introduced for a Lotka-Volterra system of a finite number of particles. For the case of an infinite number of particles, the system of 2
s+1 species is described by an integrable dynamical system with
s+1 conserved quantities. A natural extension of the
s+1 conserved quantities is given for the stochastic system of finite particles, which may give a stochastic analogue of the integrable dynamical system.
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Mitsuaki Suzuki, Makoto Saito, Eiki Hotta
1993 Volume 62 Issue 6 Pages
1829-1832
Published: June 15, 1993
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A new axisymmetric relaxed equilibrium model in the form of Grad-Shafranov equations is proposed. Utilizing the constraint condition
Kω0=∫
Vpω
A·
Bd
v developed by Bhattacharjee and Dewar instead of the helicity, this model includes a finite pressure gradient and satisfies the practical plasma boundary condition that current density at the plasma surface become zero
J(
rp)=0. We compare this model with others in the limit of a large-aspect-ratio toroidal plasma, and this model is shown to simulate other cylindrical reversed field pinch models as well as a wider class of configurations, such as diamagnetic and skin current types.
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Kenji Hiraga, Wei Sun
1993 Volume 62 Issue 6 Pages
1833-1836
Published: June 15, 1993
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A decagonal phase which was grown from an icosahedral phase in a rapidly solidified Al
70Pd
20Mn
10 alloy by annealing at 800°C was examined by means of high-resolution electron microscopy. From the high-resolution image, we directly determined a two-dimensional arrangement of atom clusters, which are structural units of the Al–Pd–Mn decagonal quasicrystal, in a wide region of about 100×100 nm
2. The main part of the observed area shows a highly ordered decagonal quasicrystal with weak linear phason strain. A tiling constructed by connecting the atom clusters with lines was compared with theoretical tilings.
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Keisuke Tanaka, Akikatsu Sawada
1993 Volume 62 Issue 6 Pages
1837-1839
Published: June 15, 1993
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The phase transition at 369.4 K in [P(CH
3)
4]
2CoBr
4 crystals has been studied using a polarizing microscope and by dielectric measurement. Domain patterns are observed on
b-plate samples and are found to move under an external stress at room temperature. This shows that [P(CH
3)
4]
2CoBr
4 crystal is ferroelastic. The phase transition is found to be of the first-order, since the phase front between the high- and low-temperature phases is observed exactly at
Tc. Values of the rotation angle φ(
T) of the optical indicatrix from the
a-axis about the monoclinic
b-axis are almost constant at 44° from room temperature to near
Tc, but discontinuously drop to zero at
Tc. As temperature is lowered, the dielectric constant ε
a′(
T) along the
a-axis shows a discontinuous drop at
Tc, and then a gradual decrease below
Tc. The phase transition in [P(CH
3)
4]
2CoBr
4 crystal is discussed in comparison with that in [N(CH
3)
4]
2CoBr
4 crystal.
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Yasuhiro Yoneda, Hirofumi Kasatani, Hikaru Terauchi, Yoshihiko Yano, T ...
1993 Volume 62 Issue 6 Pages
1840-1843
Published: June 15, 1993
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Films of BaTiO
3 single crystals with the thicknesses of 100 Å, 1000 Å and 4000 Å were grown on Pt/MgO (Pt for electric nodes, MgO for substrates) by means of the activated reactive evaporation technique. X-ray diffraction patterns were measured to clarify properties such as the temperature dependence of lattice parameters. It was found that the temperature dependences of lattice parameters and integrated intensities of Bragg reflections showed different behavior which depends on the film thickness. The relative dielectric constant ε
r and remnant polarization
Pr were measured in order to investigate the dielectric properties of the films. Film crystals of BaTiO
3 with the thickness of 4000 Å showed phase transitions different from these in the bulk state because of the effect of the substrate.
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Yositake Takane, Hiromichi Ebisawa
1993 Volume 62 Issue 6 Pages
1844-1847
Published: June 15, 1993
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Conductance of normal-superconductor contacts with disorder in the normal segment is studied numerically using a simple lattice model. When the probability of the Andreev reflection is small, the ensemble-averaged conductance is shown to be suppressed by a magnetic field. It is also found that the conductance is enhanced with an increase of randomness in the normal segment in the weak disordered regime. These anomalous features disappear in the case of complete Andreev reflection.
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Makoto Kaburagi, Isao Harada, Takashi Tonegawa
1993 Volume 62 Issue 6 Pages
1848-1852
Published: June 15, 1993
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Low-lying excited states of the spin-1 antiferromagnetic Heisenberg chain with an impurity bond are investigated in terms of domain-wall excitations by means of analytical methods as well as a method of numerical diagonalization. It is shown that 1) the impurity bond brings about a massive triplet mode in the Haldane gap, 2) the triplet state comprises three of the four ground states of an open chain, 3) the excited states with the domain wall trapped at the impurity bond, including the massive triplet mode, exhibit a Néel-type configuration of the magnetic moment around the impurity bond. On the basis of the present results, we propose a new energy versus magnetic-field diagram.
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Makoto Sakurai, Teruya Shinjo
1993 Volume 62 Issue 6 Pages
1853-1856
Published: June 15, 1993
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To study the dependence of magnetic properties on interfaces, magnetic anisotropy and magnetization of X/Co/Y (X, Y=Pd, Au, Cu) sandwiches were systematically measured using a torque and SQUID magnetometer. These films showed a marked dependence of anisotropy on interfaces. For X/Co/Y (X, Y=Pd, Au) films, the contributions of the upper and lower interfaces to the interface anisotropy were found to be different. Magnetocrystalline anisotropy for Au/Co/Au films was mainly due to the Au substrate, but the Au overlayer also contributed significantly to the anisotropy.
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Hisashi Haga, Akira Onodera, Haruyasu Yamashita, Yoichi Shiozaki
1993 Volume 62 Issue 6 Pages
1857-1859
Published: June 15, 1993
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The specific heat of ferroelectric (CH
3NHCH
2COOH)
3CaCl
2 has been measured precisely with an AC calorimeter. Two anomalies of specific heat are observed: one is associated with a ferroelectric phase transition at
T1=130 K and the other is associated with a new phase transition at
T2=65 K. This shows the existence of a new low-temperature phase, which probably corresponds to a high-pressure antiferroelectric phase reported previously. Transition entropies are estimated as 2.51 and 1.16 [J·mol
−1 K
−1] for phase transitions at
T1 and
T2, respectively.
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Tamao Matsumoto, Kimitaka Ichinose, Ken-ichi Kan’no
1993 Volume 62 Issue 6 Pages
1860-1863
Published: June 15, 1993
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Luminescence from relaxed excitons associated with guest halogen dimers was investigated for KBr:I and KCl:Br through time-resolved measurements of emission and excitation spectra using synchrotron radiation pulses from UVSOR under single-bunch operation. A
weak slow decay component was found in addition to a
main fast one in the 4.89 eV band in KCl:Br, in contrast to the 4.35 eV band of KBr:I which consists of a
weak fast decay component and a
main slow one. The fast and the slow decay components are assigned to transition from the singlet and the triplet relaxed excitons in the on-center configuration. It is suggested that the adiabatic potential energy surface for the triplet state, as well as that for the singlet state, must have a local minimum at the on-center configuration but that the triplet exciton in KCl:Br relaxes preferentially into the off-center configuration.
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Pei-Yuan Wang, Takashi Yabe, Takayuki Aoki
1993 Volume 62 Issue 6 Pages
1865-1871
Published: June 15, 1993
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A general hyperbolic solver, the CIP method, is extended to curvilinear coordinate systems. Although the coordinate is curvilinear, the velocity components in the Cartesian coordinate are used as dependent variables. The scheme is applied to strong explosion and natural convection heat transfer. The code accurately describes a cylindrically symmetric explosion even with rectangular or distorted grids. The simulation result of heat transfer agrees well with an experimental result.
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Yasuhiro Ohta, Ryogo Hirota, Satoshi Tsujimoto, Tatsuya Imai
1993 Volume 62 Issue 6 Pages
1872-1886
Published: June 15, 1993
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Solutions to the discrete KP hierarchy are expressed by two types of determinants. The first expression is the Casorati determinant and the second one is the discrete Gram type determinant. In both cases, the difference formula for the determinants are given in a simple form and the bilinear equations of the hierarchy are reduced to the Laplace expansion for determinants.
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Kiyoshi Sogo
1993 Volume 62 Issue 6 Pages
1887-1894
Published: June 15, 1993
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By introducing a time variable to the theory of orthogonal polynomials, partition functions of both the matrix model and the vertex model are shown to be described by the Toda molecule equation. In short,
the soliton is at the center of orthogonal polynomials, the matrix model and the vertex model. The differential-difference Painlevé equation appears in the case of pure gravity of the matrix model. An application to the random matrix theory of level statistics is also shown.
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Kazuaki Nakayama, Miki Wadati
1993 Volume 62 Issue 6 Pages
1895-1901
Published: June 15, 1993
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Kinematics of surfaces in 3-dimensional space is formulated in terms of the differential geometry. It is found that the introduction of nontrivial time evolution of coordinate system makes the theory transparent. Applications to some surfaces which are paremetrized by the lines of curvature are presented. Also 1-soliton solution of the zero-curvature surfaces is obtained.
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Yoshimasa Matsuno
1993 Volume 62 Issue 6 Pages
1902-1916
Published: June 15, 1993
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A unified theory is presented which describes nonlinear wave propagation in two-layer inviscid and incompressible fluid of arbitrary depth. We consider the two-dimensional systems, in which a layer of lighter fluid overlies a layer of heavier one resting on a flat bottom. The two cases of rigid and free upper boundaries are dealt with separately. We derive approximate nonlinear evolution equations (NEEs) for interfacial and free surface elevations on the basis of a systematic perturbation method with respect to the steepness parameter. We also discuss on NEEs arising from various limiting cases of fluid depth and compare them with existing NEEs. It is found that our theory includes almost all existing nonlinear theories as special cases.
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Hang-yu Ruan, Sen-yue Lou
1993 Volume 62 Issue 6 Pages
1917-1921
Published: June 15, 1993
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The inverse of the strong symmetry (recursion opterator) of Jaulent-Miodek hierarchy are expressed explicitly by means of the solutions of the Shrodinger equation. Four new sets of symmetries are obtained after acting the inverse strong symmetry on three new seed symmetryes and one known seed symmetry.
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Ko Okumura
1993 Volume 62 Issue 6 Pages
1922-1926
Published: June 15, 1993
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We study the
U(
M⁄
N) supergroup keeping in mind its connection with electronic Hamiltonians. It is explicitly shown that the generators of the supergroup
U(
N⁄
N) can be expressed by Clifford operators or Fermi operators. A multi-band supersymmetric electronic model is suggested.
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C. C. Chow, S. J. Fromm, H. Segur
1993 Volume 62 Issue 6 Pages
1927-1931
Published: June 15, 1993
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The behaviour of a nonlinear Hamiltonian amplitude equation describing the modulation of plane waves in unstable media is analysed. In the defocusing case where the nonlinearity is destabilizing, solutions of the equation can blow up in finite time. In the focusing case, there is a family of stable solutions and there are indications of chaotic orbits away from these solutions.
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Takeshi Iizuka, Miki Wadati
1993 Volume 62 Issue 6 Pages
1932-1938
Published: June 15, 1993
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Scattering of weakly nonlinear waves in a one-dimensional anharmonic lattice due to a very heavy impurity is investigated. Lattice waves are assumed to be slowly varying. The incident, reflected and transmitted waves are governed by the Korteweg de Veries (K-dV) equations on different coordinates. We analytically construct the transmitted and reflected waves from the incident wave. In particular, scattering of an incident soliton is analyzed. It is shown that at least one soliton is always generated both in the transmitted and the reflected waves. More than two transmitted solitons are generated if the mass of the impurity is large enough. We also evaluate the amplitudes of the reflected and transmitted solitons.
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Kaoru Awaka, Gen Tatara, Hidetoshi Fukuyama
1993 Volume 62 Issue 6 Pages
1939-1950
Published: June 15, 1993
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A new formalism to treat the tunneling processes of a heavy particle coupled to degenerate electron systems has been presented. This simple and transparent method follows that of Caldeira and Leggett in a general framework, but the term representing the dissipation is given in terms of the imaginary part of the retarded density correlation function as far as the coupling is weak. Hence our method can incorporate the microscopic details of the electronic systems such as mutual interactions and randomness. It is found that for the Luttinger liquid, the dissipation can be either sub- or super-Ohmic depending on the type of interaction, while near the Anderson transition there exists a crossover from Ohmic to sub-Ohmic dissipation. In the case of sub-Ohmic dissipation, the tunneling rate is found to vanish discontinuously above some critical value as a function of the strength of dissipation.
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Haruhiko Ito, Takahisa Mitsui, Katsuyuki Kobayashi, Tsutomu Yabuzaki, ...
1993 Volume 62 Issue 6 Pages
1951-1963
Published: June 15, 1993
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A new optical pumping scheme utilizing selective reflection is proposed and studied for the first time. This method enables us to observe the spin-polarization of atoms even at the high density, at which the pumping beam cannot be transmitted through a sample cell. Theoretical analysis shows that the light reflectivity at the glass-vapor interface is strongly dependent on the direction of the macroscopic magnetic moment of optical pumped atoms. Two types of demonstrating experiments are carried out with Cs and Rb vapors at the temperature ∼200°C. In the transverse pumping experiment with a modulated laser beam, asymmetry of the magnetic resonance signal with respect to the inversion of the magnetic field direction is observed as predicted by the theory. In the longitudinal pumping experiment, the transfer of a large amount of the magnetic moment by spin-exchange collisions is directly observed.
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Igor I. Gancheryonok, Yasuo Kanematsu, Takashi Kushida
1993 Volume 62 Issue 6 Pages
1964-1977
Published: June 15, 1993
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We present consistent theoretical studies of the optically heterodyned polarization interferometry (OHPI) with collinear circularly and linearly polarized interacting beams in the framework of the 3rd-order nonlinear susceptibility. A new method for measuring the phase of the nondegenerate susceptibility that is based on the dependence on the pump beam intensity in the standard OHPI scheme is proposed. The conditions for observing the signals which are purely due to linear or circular light-induced dichroism and birefringence are discussed and new experimental arrangements are suggested. Further, the optimum sample length to detect the OHPI signal is derived. The line shape of the OHPI signal and the elimination of the broad background in nonlinear polarization spectrposcopy are also discussed.
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Kh. S. Singh, P. Khastgir, S. P. Ojha, P. K. Choudhury
1993 Volume 62 Issue 6 Pages
1978-1983
Published: June 15, 1993
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An investigation has been made of the electromagnetic wave propagation in a medium with two regions, having different chiral admittances, separated by a parabolic cylindrical surface. The resulting guide is analogous to a circular chirowaveguide when the circle is degenerated into a parabola. The eigenvalue equation and the cutoff conditions of such a chirowaveguide have been derived for different special cases.
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Setsuko Mukai, Masahiro Nakagawa
1993 Volume 62 Issue 6 Pages
1984-1992
Published: June 15, 1993
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In this paper, the elastic distortions of compressible smectics are investigated near the boundary of a pair of opposite chevron layer structures on the basis of the elastic theory. The Lagrange multipliers are explicitly taken into account to assure the orthogonality of the wave vector
a and the
c-director as well as the normalization of
c. In addition an external DC electric field effect is also investigated. From numerical computations, it is concluded that there exists a parallelogram region with a flat layer and a uniform
c-director configuration between the two opposite chevrons. In addition the external electric field is found to break up the symmetry of the layer structure and result in the layer undulation along the electric field.
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Mitsuaki Funakoshi
1993 Volume 62 Issue 6 Pages
1993-2006
Published: June 15, 1993
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In a two-layer fluid system, both wave generation by bottom topography and resonant interaction between two wave modes are examined simultaneously. An evolution equation is derived which describes not only the resonant interaction between long internal mode and the wave packet of short surface mode, but also the generation of internal mode due to the resonant motion of the fluid relative to a bottom unevenness of large horizontal scale. According to this equation, steady coupled waves trapped by a localized symmetric bottom unevenness of sech
2-type are computed numerically both for positive and negative unevenness. Consequently, in addition to symmetric waves with one or two peaks in short-wave envelope, a variety of waves with many peaks, antisymmetric waves, and asymmetric waves are found.
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Kwok W. Chow
1993 Volume 62 Issue 6 Pages
2007-2011
Published: June 15, 1993
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The phase speeds or the dispersion relations for the periodic waves of certain nonlinear evolution equations can be expressed in remarkably compact forms by using theta functions.
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Azusa Fukano, Yasuhiko Sentoku, Masatada Ogasawara
1993 Volume 62 Issue 6 Pages
2012-2020
Published: June 15, 1993
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Two-stream instability induced by a uniform light ion beam of finite radius propagating in a background plasma is investigated numerically. Radial structure of the instability is obtained by a linear electromagnetic stability analysis. Problem is solved as an eigenvalue problem. Frequency and growth rate of the instabiblity are obtained as the eigenvalues, and radial profile of perturbed physical quantities is obtained as the eigenfunction. Two types of the perturbation mode are obtained. One is that it’s perturbation appears inside of the beam and is characterized by a radial mode number. Another is that the perturbation appears at the surface of the beam. It is also shown that although the growth rate increases with the radial mode number, it converges to a constant value for large mode number.
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Katsuhiro Nishinari, Kanji Abe, Junkichi Satsuma
1993 Volume 62 Issue 6 Pages
2021-2029
Published: June 15, 1993
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The Davey-Stewartson equations are derived in a plasma system by the reductive perturbation method. Certain particular solutions are obtained by means of a linearization technique. One of them shows an interesting behavior, which may betermed “reconnection” of solitons.
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Giovanni Gnudi, Tadatsugu Hatori
1993 Volume 62 Issue 6 Pages
2030-2037
Published: June 15, 1993
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A hamiltonian for the helical magnetic field lines in the vacuum has been constructed. The hamiltonian is obtained using Lie perturbation expansion techniques and it is given up to the second perturbative order. The hamiltonian is given both for the cylindrical limit approximation of the field and for the toroidal case.
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Yoshiomi Kondoh, Kiwamu Sugisaki, Yasuyuki Yagi, Youichi Hirano, Toshi ...
1993 Volume 62 Issue 6 Pages
2038-2047
Published: June 15, 1993
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Experimental data on two quite different types of devices, a simple toroidal
Z pinch without toroidal field coils and a reversed field pinch (RFP), are analyized by using the partially relaxed state model (PRSM). It is shown that the experimental data on both two devices fit fairly well theoretical curves by the PRSM with common parameter range included in the model, suggesting that some common physical process of relaxation is taking place together with some common loss process.
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Takashi Sakuma, Sadao Hoshino
1993 Volume 62 Issue 6 Pages
2048-2050
Published: June 15, 1993
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Neutron scattering measurement of the diffuse scattering of single crystal α-AgI was performed with the
ΔE\simeq0 scan method. The feature of the observed intensity of the diffuse scattering was explained by the theory including the correlations among the thermal displacements of atoms. Most of the intensities of the diffuse scattering with the
ΔE\simeq0 scan method corresponds to the static disorder scattering among silver atoms.
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Hirohiko Sato, Norimichi Kojima, Seiichi Kagoshima
1993 Volume 62 Issue 6 Pages
2051-2061
Published: June 15, 1993
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A quasi two-dimensional metal K
3Cu
8S
6 has two phase transitions at
T1 (153 K) and at
T2 (55 K), accompanied by an incommensurate (between
T1 and
T2) and a commensurate (below
T2) superstructures, respectively. On the other hand, the resistivity of Rb
3Cu
8S
6, which is isostructural with K
3Cu
8S
6, suggests that Rb
3Cu
8S
6 has only the
T1 transition. In order to investigate the superstructures of Rb
3Cu
8S
6, X-ray diffuse scattering studies were carried out. The results show that an incommensurate superstructure with a wave vector of (0 η 0), η\simeq0.45, appears between
T1 and the measuring lowest temperature (about 15 K). The temperature dependence of the intensity of the superstructure is that of an ordinary charge-density wave and there is no evidence for the
T2 transition in Rb
3Cu
8S
6. The X-ray scattering results on the mixed crystals (K
1−xRb
x)
3Cu
8S
6 are also reported.
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Yutaka Aikawa, Katsuhiko Fujii
1993 Volume 62 Issue 6 Pages
2062-2065
Published: June 15, 1993
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The structure of amorphous metals has been studied by applying the theory of instability phenomena in crystals. As the results, it has been found that the structural unit in amorphous state prepared from face centered cubic crystal forms the icosahedron with 13 atoms.
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Hongye Sun, Hiroshi Orihara, Yoshihiro Ishibashi
1993 Volume 62 Issue 6 Pages
2066-2073
Published: June 15, 1993
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Photon-correlation spectroscopy was performed to observe relaxation modes in an antiferroelectric liquid crystal (R)-MHPOBC. A phase mode in the SmI
A* phase, which is the same as one in the incommensurate phase of solid, was observed for the first time. From the dispersion relations of the Goldstone modes in the SmC
γ* and SmC
A* phases, the ratios of orientational elastic constants to the viscosity coefficient were obtained as a function of temperature. A linear temperature dependence of the inverse pitch in the SmC
A* phase was also found, which was discussed on the basis of the phenomenological theory.
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Eiko Matsushita
1993 Volume 62 Issue 6 Pages
2074-2078
Published: June 15, 1993
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In view of the importance of the role of host lattice on the proton configurations in hydrogen-bonded crystals, a cluster theory is developed to explain the phase transition in one-dimensional ferroelectrics PbHPO
4. The correlation between the spontaneous polarization and Pb–PO
4 translational mode frequency is analyzed on the basis of a pseudo-spin model for the proton system. It is shown that rather high transition temperature
Tc in this system is related with the large anisotropy among proton-proton correlations and the renormalization of the host lattice into proton system.
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Eiko Matsushita
1993 Volume 62 Issue 6 Pages
2079-2087
Published: June 15, 1993
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Basing on the previous study on Isotope effect in hydrogen bonded crystals, the equation for the critical temperature
Tc is presented in a cluster approximation. The obtained
Tc includes the information of hydrogen bond lengths (oxygen-oxygen distance
RO–O, hydrogen-hydrogen distance
RH–H etc.), and has an extended form of that in pseudo-spin model which gives the exact solution in the one-dimensional hydrogen bonded systems. From theoretical viewpoint, experimental data of
Tc-
RO–O and
Tc-
RH–H relations are analyzed. It is pointed out that the quantum effect of H(D) atoms leads to the isotope effect in these geometric values, but this isotope effect contributes to
Tc in a quite different manner depending on
RO–O.
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Masashige Matsumoto, Yoji Ohashi
1993 Volume 62 Issue 6 Pages
2088-2097
Published: June 15, 1993
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The quantum diffusion of muons in superconductors is studied for two cases: superconductors with impurities and without impurities. The result shows that in the case of pure superconductors the tunneling probability from one site to a nearest neighbor site increases exponentially with the decrease of temperature. In the case of impure superconductors there is a competition among three energies: temperature, superconducting energy gap, and the energy difference between two neighbouring sites. As a consequence the tunneling probability has an interesting structure which reflects sensitively the energy gap.
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Naoya Takeda, Katsunori Tanaka, Masaki Kagawa, Akira Oyamada, Noriaki ...
1993 Volume 62 Issue 6 Pages
2098-2102
Published: June 15, 1993
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We have studied the Fermi surface and the cyclotron mass of a semimetallic heavy fermion compound YbAs both in the antiferromagnetic state and the paramagnetic state. We have found the Fermi surface of three ellipsoidal electron surfaces and one spherical hole surface, and that the shape of these Fermi surfaces is the same in both states. In addition, we have found that the temperature dependence of the dHvA oscillatory amplitudes change anomalously at the Néel temperature. This anomaly is ascribed to the change of the cyclotron mass and the Dingle temperature at the Néel temperature. To explain the large electronic specific heat coefficient, the extremely heavy hole surface with about 10
3 m0 should exist.
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Katsuhiko Takegahara, Hisatomo Harima, Yasunori Kaneta, Akira Yanase
1993 Volume 62 Issue 6 Pages
2103-2111
Published: June 15, 1993
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One-electron energy band structures for Ce
3Pt
3X
4 (X=Sb and Bi), which belong to the valence fluctuation regime with an energy gap, are calculated by a self-consistent LAPW method with the local density approximation. The valence bands consist of the X
p and the Pt 5
d states and the conduction bands are derived from the Ce 5
d states. With depressing the valence bands, the empty Ce 4
f bands are located between these bands and thus a narrow band gap appears at the Fermi level. This result explains reasonably the semiconductor-like property of these compounds.
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Shigenori Tanaka
1993 Volume 62 Issue 6 Pages
2112-2119
Published: June 15, 1993
Released on J-STAGE: June 01, 2007
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The variational quantum Monte Carlo method has been applied to the first-principles calculation of the cohesive energy of NiO with the fcc type-II antiferromagnetic structure. The trial wave functions used for the calculations for O and Ni atoms and solid NiO have been chosen to be of the form of a Jastrow exponential factor multiplying a Slater determinant. The pseudopotentials introduced to avoid the large fluctuations of energy in the core region have been evaluated with the aid of a local approximation whose utility and accuracy were assessed through comparison with the nonlocal method in the calculation for isolated atom. By appropriate choice for the form of the trial functions, a promising result has been obtained for the calculated value of cohesive energy, which is consistent with experiment.
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Norihiko Kamata, Koji Yamada, Noboru Miura, Laurence Eaves
1993 Volume 62 Issue 6 Pages
2120-2128
Published: June 15, 1993
Released on J-STAGE: May 29, 2007
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By applying pulsed high magnetic fields up to 40 T perpendicular (
B⊥⊥
I) and pallarel (
B⁄⁄⁄⁄
I) to the current direction, a distinct role of emitter states in the magneto-tunneling processes through resonant tunneling diodes has been investigated. The
B⊥ dependence of the threshold voltage in current vs. voltage (
I-
V) curves has been explained consistently by tunneling from a combined magneto-electric state of a 1-dimensional (1D) emitter to that of a 0-dimensional (0D) well state. We observed a drastic current decrease above
B⁄⁄=10 T under constant applied voltage below the negative differential conductivity region together with multi-peaked
I-
V curves with hysteresis at above
B⁄⁄=30 T. These distinct features were analyzed by a self-consistent model of the charge build-up effect and the energy configuration of the 0D emitter, 1D emitter and 0D well states.
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Atsushi Goto, Hiroshi Yasuoka, Hidefumi Yamamoto, Teruya Shinjo
1993 Volume 62 Issue 6 Pages
2129-2140
Published: June 15, 1993
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The spatially oscillating electron spin polarization in Cu layers of [Ni/Cu] superlattice has been investigated by the nuclear magnetic resonance method. The damping exponent of the polarization oscillation deduced from line widths of Cu NMR spectra has been shown an unexpected value “−1”. This fact reflects a topology of the Fermi surface in Cu layers. Moreover, the spectra have shown noticeable anisotropy; the spectral shape depends on the angle between the external field and the sample surfaces. From analyses of the anisotropy, we have concluded that the anisotropy originates from a change not in χ(
q) of Cu layers but in the initial conditions of the oscillation determined by the interfacial conditions. From
63Cu spin-lattice relaxation time (
T1) measurements, an enhancement of the density of states at the Fermi level compared with bulk one has been found, which suggests a change in the band structure of Cu layers from the bulk one.
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K. V. Ramanathan
1993 Volume 62 Issue 6 Pages
2141-2143
Published: June 15, 1993
Released on J-STAGE: June 01, 2007
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Wide-line proton NMR spectra of ammonium thiocyanate have been recorded at 77 K as a function of external hydrostatic pressure. Contrary to expectations the line-width and the second moment decrease with the increase of pressure. This, however, is in accordance with the anomalous behaviour observed in other magnetic resonance studies of this compound and can be understood in terms of the change of electron density around the nitrogen atom of the SCN
− group.
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G. K. Pandey, M. Massey, K. L. Pandey
1993 Volume 62 Issue 6 Pages
2144-2154
Published: June 15, 1993
Released on J-STAGE: May 29, 2007
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Electric field induced dichroism of the UV absorption and dipole relaxation behavior of OH
− in CsBr at low temperature is unlike its behavior in other alkali halides. Single-multiplet tunneling model, quite successful in explaining the behavior of OH
− in most of the alkali halides, fails in the case of CsBr. It is shown that the two-multiplet tunneling model, introduced in previous work to explain some of the anomalous results in other systems, successfully accounts for the anomalous behavior of OH
− in CsBr.
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Takashi Fujikawa
1993 Volume 62 Issue 6 Pages
2155-2165
Published: June 15, 1993
Released on J-STAGE: June 01, 2007
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Short-range order multiple scattering approach to study XANES spectra is considered here based on the first principle many-body X-ray absorption intensity formula beyond sudden (intrinsic) approximation. The interference effects between intrinsic and extrinsic loss of a photoelectron is explicitly taken into account and discussed in detail. One important conclusion is the suppression of the jump structure for an intrinsic loss threshold because of the subtle cancellation of these two effects. An efficient new method to treat full multiple scattering processes is developed which is based on partitioning technique. This theory allows us to treat infinite and finite multiple scattering on the same footings: We can exclude unimportant full multiple scatterings but include important full multiple scatterings.
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Taichi Terashima, Norimichi Kojima, Hiroshi Kitagawa, Hiroshi Okamoto, ...
1993 Volume 62 Issue 6 Pages
2166-2173
Published: June 15, 1993
Released on J-STAGE: May 29, 2007
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The polarized optical reflectivities from the basal planes of incommensurate layer compounds (CeS)
1.2NbS
2 and (CeS)
0.6NbS
2 have been measured at room temperature. These two compounds have a stage-1 and a stage-2 structure, respectively, when considered as intercalation compounds of NbS
2. The main features appeared in the interband transition region of the spectra can be correlated with those in the reflectivity spectrum of the host material NbS
2 on the basis of the rigid-band model for the host electronic band-structure. The oscillator fits to the free carrier reflectivities in the spectra have been made and the analysis of the plasma frequencies suggests a large charge transfer from the CeS layer to the host NbS
2 layer.
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Hiroshi Mitomo, Shodo Kobayashi, Shigeo Iwayanagi, Toshiharu Takizawa, ...
1993 Volume 62 Issue 6 Pages
2174-2179
Published: June 15, 1993
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Hydrations and phase transitions of ammonium, sodium and potassium salts of phosphatidylserines (PS) were investigated by small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC). The increase in long spacings for NH
4+–PS by addition of water was slightly smaller than those for the other PS salts, implying that a small amount of water penetrated into the hydrocarbon regions. The long spacings for PS salts and water system were reduced by addition of CaCl
2. A mixture of phosphatidylcholine (PC) and PS in KCl aqueous solution gave a long spacing of 59 Å, while it separated into two long spacings at 65 and 55 Å in 1 mol CaCl
2 solution. This SAXS result shows that Ca
2+ ion induces not only two dimensional, but three dimensional phase separation of the mixture of PC and PS. The phase transition temperature of the anhydrous NH
4+–PS was lowest among those of the three PS salts, but fully hydrated NH
4+–PS had the highest transition temperature among them.
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Naokata Takeyama, Kimie Nakashima
1993 Volume 62 Issue 6 Pages
2180-2181
Published: June 15, 1993
Released on J-STAGE: June 01, 2007
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