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Masao Nomura
1988 年 57 巻 11 号 p.
3653-3656
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Novel solutions to the star-triangle equation for the IRF model are presented which are described in terms of 6−
j and 9−
j symbols. Additivity of spectral parameters does not hold in this case.
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Shigeo Kida, Youichi Murakami
1988 年 57 巻 11 号 p.
3657-3660
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The energy decay law of turbulence is investigated by solving the Navier-Stokes equation numerically. High symmetry is imposed on the velocity field. The initial energy spectrum has the form of
E(
k)∝
kn exp [−
Ak2],
n and
A being constants. It is found that the energy decreases algebraically in time as ε(
t)∝(
t−
t0)
−p, where
p≈1.25 and 1.30 for
n=2 and 4, respectively. During these algebraic decays the microscale Reynolds number changes between 20∼10. The Kolmogorov similarity law holds irrespective of the difference of the large-scale motions or the difference of the energy decay laws.
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Motomi Iida, Takashi Maekawa, Hitoshi Tanaka, Shunsuke Ide, Kazuo Ogur ...
1988 年 57 巻 11 号 p.
3661-3664
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Sawtooth oscillations appearing in Ohmically heated (OH) plasmas are suppressed by the lower hybrid current drive (LHCD) in the WT-3 tokamak (
R=65 cm,
a=20 cm,
Ip\simeq100 kA, \bar
ne=1−2×10
13 cm
−3,
qa\simeq4.5, and
PLH\gtrsim100 kW). After the suppression, sawteeth reappear following
m=1 oscillations in the LHCD plasmas. The latter sawteeth have a large amplitude and long period (
Ts=2–5 msec), compared with the former one (
Ts=0.5–1.5 msec). Furthermore, they do not accompany a precursor and crash very fast.
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Taizo Yamamoto, Yukikuni Akishige, Etsuro Sawaguchi
1988 年 57 巻 11 号 p.
3665-3667
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
For determining the space group of the intermediate phase (74 K<
T<222 K) of hexagonal-type BaTiO
3, X-ray oscillation photographs of a ‘twin-free’ single crystal have been analyzed. Twins which usually occur below 222 K have been successfully eliminated by applying a stress on the crystal. The space group is determined as orthorhombic C222
1-D
25.
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Hideki Seto, Yukio Noda, Yasusada Yamada
1988 年 57 巻 11 号 p.
3668-3671
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
A detailed X-ray diffraction investigation has been carried out in the vicinity of fcc to fct phase transition temperature in Fe–Pd alloys in order to elucidate the premartensitic phenomena. Using a high-resolution spectrometer and with fine temperature control, the temperature dependence of the splitting of Bragg reflection as well as diffuse scattering were measured in detail. Just above the martensite transformation temperature, we found a new intermediate phase. This structure is characterized by a coherent mixture of the two kinds of tetragonal lattices with different tetragonality and is interpreted as a spatially modulated fct phase.
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Shingo Katsumoto, Shun-ichi Kobayashi, Hatsumi Urayama, Hideki Yamochi ...
1988 年 57 巻 11 号 p.
3672-3673
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Specific heat
C of κ-(BEDT–TTF)
2Cu(NCS)
2 was measured between
Tc(10.4 K) and 3 K. An anomaly around
Tc was observed. The specific heat data show unusual bending below
Tc in the
C⁄
T versus
T2 plot. At the lowest temperatures,
C obeyed the
T3 law and no residual
T-linear contribution was observed.
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Takehiko Mori, Hiroo Inokuchi
1988 年 57 巻 11 号 p.
3674-3677
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Thermoelectric power of organic superconductors, β-(BEDT–TTF)
2I
3 and (BEDT–TTF)
2Cu(NCS)
2 (BEDT–TTF: bis(ethylenedithio)-tetrathiafulvalene) is calculated by the integration of the Boltzmann equation on the basis of the two-dimensional tight-binding band models. This calculation provides the interpretation of the observed complicated temperature dependence and anisotropy of the thermoelectric power and a tool estimating the transfer integrals.
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Junichi Wakabayashi, Atsuyuki Fukano, Shinji Kawaji, Kazuhiko Hirakawa ...
1988 年 57 巻 11 号 p.
3678-3681
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Magnetotransport experiments on a high mobility GaAs/AlGaAs heterostructure in magnetic fields up to 27 T and at temperatures down to 20 mK were performed. A structure in ρ
xy which shows the existence of the quantum liquid state at the filling factor ν=1⁄7 in a magnetic field up to 18 T was observed. However, the structure of ρ
xy with ν=1⁄7 at a magnetic field of 25 T was not observed. The possibility of the growth of the charge density wave and the coexistence of the quantum liquid state and CDW state due to the potential fluctuations are discussed in this paper.
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Muneyuki Date
1988 年 57 巻 11 号 p.
3682-3685
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
A simple incommensurate mean field model is introduced to explain complex magnetic phase diagrams of various rare-earth intermetallic compounds such as CeSb and CeBi. The eigenstates and their energies of the Ising spin chain immersed in the exchange field with magnitude
J, wave vector
k and phase δ are determined. The spin
S(
r) is assumed to point in the local field direction. The eigenstates are classified into three groups, the irrational states, rational states {
k} with δ=0 and rational states {
k} with δ=π⁄2
n where
n is the state index given by a positive integer. The phase diagram of CeSb is sketched by the model. It is emphasized that the present model suggests an effect of the spin coupling to the formation of conduction band electrons and the effect on the heavy fermion and superconductivity is discussed.
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Hideki Yoshizawa, Setsuo Mitsuda, Hideaki Kitazawa, Koichi Katsumata
1988 年 57 巻 11 号 p.
3686-3689
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
By neutron quasielastic scattering experiments, we observed a two-dimensional antiferromagnetic diffuse scattering in a superconducting La
1.92Sr
0.08CuO
4−δ sample at room temperature as well as in a superconducting phase. The line shape of the magnetic diffuse scattering at 295 K is a conventional Lorentzian, whereas it changes to a non-Lorentzian shape at low temperatures, presumably being a double peak structure with the peaks shifted by 0.05
a* from the antiferromagnetic zone center.
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Hiroyuki Nagai, Masashi Takigawa, Hiroshi Yasuoka
1988 年 57 巻 11 号 p.
3690-3693
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The Knight shift (
K) and the spin-lattice relaxation time (
T1) of
59Co nuclei have been measured in the weak Pauli paramagnet, Y(Ni
1−xCo
x)
2. The values of
K and (
T1T)
−1 for small
x are larger than those for large
x and they are insensitive to
T and nearly constant, while the susceptibility increases with increasing
x. These anomalous phenomena are explained by the change in the density of state of the Y atom and the 3d atom with
x.
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Syuji Kawada
1988 年 57 巻 11 号 p.
3694-3697
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
A mechanism of the drastic reduction of the relaxation time by doping of a small amount of KOH into ice Ih is discussed using the Eyring’s theory of the elementary rate process by introducing a phenomenological parameter. It is deduced that this reduction of the relaxation time is strongly attributed to the release of water molecules from the ice rule which acts as a strong limitation to proton rearrangement.
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Kazuo Gesi, René Perret
1988 年 57 巻 11 号 p.
3698-3701
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Dielectric properties of the {N(CH
3)
4}
2ZnI
4 crystal were studied between room temperature and 4.2 K. Two phase transitions were seen from dielectric constant anomalies at
T1=254 K and
Tc=210 K on cooling. Ferroelectric hysteresis loops were observed along the
c-direction below
Tc with a low frequency applied field of 0.0025 Hz. The spontaneous polarization obtained by pyroelectric charge measurement tended to be 2.5×10
−3 C/m
2 at 0 K.
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Haruki Nakamura
1988 年 57 巻 11 号 p.
3702-3706
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
A reaction field in a protein molecule due to aqueous solvent, which is polarized by charges of the protein, has been calculated numerically. First, a Poisson equation for a macroscopic dielectric model of a protein
in vacuo was solved by the self-consistent boundary method. Next, Poisson and Poisson-Boltzmann equations for the model of a protein in aqueous solvent were solved in the same manner. The reaction field was then obtained by taking the difference between the potentials of these two systems. The results agreed well with those calculated analytically for simple model cases. Applications of the present method of the particle-particle/particle-mesh algorithm were discussed for actual protein-solvent systems.
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Kimiaki Konno
1988 年 57 巻 11 号 p.
3707-3713
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Extending an independent variable into complex and introducing an auxiliary function, we investigate nonlinear interactions between solitons for the Toda lattice by observing behavior of zeros of the function. The Newton’s method calculating them is identified with a complex dynamical system. We present numerical results of the Fatou set on the dynamics. According to motion of solitons, the set changes surprisingly. Since soliton solutions include the exponential function, the Fatou set is different from that of the polynomial and the rational functions.
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Takuji Kawahara, Masanori Takaoka
1988 年 57 巻 11 号 p.
3714-3732
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Weak interactions of the oscillatory solitary waves for the fifth order Korteweg-de Vries equation are investigated in terms of a soliton lattice model. Numerical solutions of the three pulse periodic system show two types of chaotic changes of the inter-pulse distances, depending on the total periodicity length. As an increase of the deviation of the initial value from a fixed point with center-like singularity, periodic motions show frequency down-shifts and lead to chaotic behaviour. A bounded motion associated with one stable fixed point involves chaotic behaviour that is an irregular manifestation of modulation. Another motion associated with three stable fixed points involves chaotic behaviour ascribed to an irregular meandering among these fixed points. Observed frequency down-shifts are explained in terms of a perturbation analysis.
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Makoto Inoue, Tetsuhiko Chikyu, Xiao Hu, Masuo Suzuki
1988 年 57 巻 11 号 p.
3733-3741
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The ground states of the antiferromagnetic Heisenberg model on the triangular and square lattices are discussed with use of the combinatorial method on the basis of Anderson’s RVB (resonating-valence-bond) variational wave-function. Some properties of RVB states are studied systematically for finite system-size
N up to 20 and are compared to the exact values. For the triangular lattice the estimated energy value
ERVB=−2.08 is closer to the exact value than that of the spin-wave theory. The value
ERVB=−2.36 is estimated for the square lattice. For the square lattice our RVB state is closer to the exact ground state than the Néel state is in the sense of a wave-function. The dimer problem has a close relation to RVB states and is used to count exactly the number of singlet-pair configurations.
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Takao Yamamoto, Takeo Izuyama
1988 年 57 巻 11 号 p.
3742-3752
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The statistical mechanics of the assembly of the dislocation lines in a three dimensional crystal is developed. Using the transfer matrix method, the statistical mechanics of the dislocations is transformed into the ground state problem of the two dimensional Fermion-Boson system. This approach gives a convincing proof for the free energy expression:
f(ρ)=−
F1ρ ln
Cρ+
F2ρ+
F3ρ
2,
where ρ is the dislocation density,
F1 and
F3 are positive constants, and
C is a constant of the order
a2 (
a being the lattice spacing). The constant
F2 is positive at low temperatures but is negative at high temperatures.
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Makoto Katori, Masuo Suzuki
1988 年 57 巻 11 号 p.
3753-3761
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The coherent-anomaly scaling is investigated for the approximations derived on the basis of the cluster-variation method (CVM). All of the mean-field critical coefficients are calculated in the Weiss, the Bethe and the Kikuchi approximations for the three-dimensional Ising model on the simple cubic lattice. The dynamical coefficients of the relaxation time are also obtained in the corresponding approximations for the kinetic Ising model. The non-classical values of critical exponents as well as the true value of critical temperature are estimated by extrapolating these approximants by the coherent-anomaly method. The results suggest that the approximations by the CVM possess the property of coherent-anomaly scaling.
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Kulwant Singh, T. S. Gill, K. Singh
1988 年 57 巻 11 号 p.
3762-3765
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The K-capture probabilities in the decay of
175Hf to 433 and 343 keV levels have been determined by the KX-ray-gamma ray sum peaks observed with a high resolution single intrinsic Ge detector.
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Hirokazu Tezuka
1988 年 57 巻 11 号 p.
3766-3772
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Differential cross sections are calculated for photodisintegration of the two-nucleon systems in
4He and
9Be. Data used in the analysis are obtained from the reactions of
4He(γ,
p) and
9Be(γ,
p) with incident photon energy from 200 to 420 MeV, and outgoing protons at 30°, 60°, 90° and 105° in the laboratory system. The experimental cross sections are well-reproduced as a whole with correlated two-nucleon relative wave function.
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Nicolò Arena, Sebastiano Cavallaro, Giovanni Fazio, Giorgio Gia ...
1988 年 57 巻 11 号 p.
3773-3777
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The αd bidimensional spectra for the
7Li(
3He, αd)α reaction at
E(
3He)=11.5 have been measured. The width of the (
Jπ=1
+,
T=0) level of the
6Li nucleus at
Ex=5.65 MeV excitation energy have been deduced. The
Γ value of (1.6±0.3) MeV found is in line with the values deduced by the same reaction at incident energies of
E(
3He)=2.5 and 5.0 MeV. This shows that, in the range between 2.5 and 11.5 MeV, the apparent
Γ width value does not seem to depend on the
3He bombarding energy.
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Yoichiro Furutani, Hiroo Totsuji, Kunitaka Komaki, Masahiro Tanabe
1988 年 57 巻 11 号 p.
3778-3789
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
An effective potential of an isolated partially ionized high-
Z ion, calculated within the framework of the statistical models of atoms, is injected into the one-electron Schrödinger equation, in view of evaluating the electron density and comparing it with the results of statistical models. Starting from this initial value, a self-consistent electron density is obtained on the basis of the density functional theory, where quantum natures of electrons are fully taken into account. Several remarks are given on the boundary conditions imposed upon the isolated ion.
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Shinichiro Yanase, Koji Nishiyama
1988 年 57 巻 11 号 p.
3790-3795
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Bifurcating solutions are obtained for a flow through a slightly curved tube of rectangular cross-section. An aspect ratio of cross-section, γ, is changed over 1≤γ≤5 with the Dean number fixed to be 100. If γ<3.02, there is only a two-vortex solution. If γ≥3.02, there are dual solutions one of which is a two-vortex solution, the other is a four-vortex solution. Numerical solution of the unsteady Navier-Stokes equation at γ=4.9 shows that a two-vortex solution changes toward a four-vortex solution when it is disturbed by asymmetric disturbances.
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Masaki Takashima
1988 年 57 巻 11 号 p.
3796-3801
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The transverse plane waves propagating in the horizontal direction in an unbounded binary fluid mixture having vertical temperature and concentration gradients are investigated in the presence of the Soret effect. It is shown that undamped waves cannot exist since the conditions for the propagation of undamped waves contradict the stability criteria for the undisturbed basic state. It is also shown that weakly damped waves can exist under the conditions that the undisturbed basic state is stable.
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Tadao Honzawa
1988 年 57 巻 11 号 p.
3802-3808
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Controlled excitation of nonlinear multimode waves, including slow and fast ion-beam modes as well as an ion-acoustic mode, has been realized in a linearly stable ion-beam-plasma system. The mechanism for the coexcitation of two unlike waves observed in the system is also clarified. Furthermore, nonlinear dispersion relations of the beam modes are experimentally determined from the amplitude dependences of the wave velocities and widths. The results are compared with the theoretical ones.
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Atsushi Kamitani
1988 年 57 巻 11 号 p.
3809-3819
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The effects of the flux hole on the magnetohydrodynamic (MHD) stability of the spheromak are investigated. The plasma is assumed to be confined in a drum-type flux conserver and is assumed to be in a force-free magnetic field. A numerical code to integrate the linearized MHD equation is developed and the linear growth rates of the
n=1 mode are evaluated as functions of the flux-hole size and the prolateness parameter
L⁄
R. Here
n is the toroidal mode number, and
L and
R denote the height and the radius of the flux conserver. The results of computations show that the flux hole has the destabilizing effects, but stable configurations exist when the flux hole is small and the flux conserver is oblate enough to satisfy
L⁄
R\lesssim1.8±0.1.
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T. S. Yeoh, S. G. Teoh, H. K. Fun
1988 年 57 巻 11 号 p.
3820-3823
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
X-ray diffraction data from as-grown and annealed single crystals of Sn
1−x(Me)
xTe (Me=Cr, Mn, Fe, Co and Ni;
x ranges from 0.5 at% to 5.0 at%) were collected using the Syntex P2
1 four-circle diffractometer and subsequently analysed using the SHELX-76 computer programmes to obtain the relative shifts in positions of Sn and dopant, Me, in a unit cell. It has been found that substitution occurs on doping whereby the Me ion replaces the Sn ion. In addition, the Sn and Me ions are displaced from the original undoped Sn ion positions.
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Masaaki Matsuda, Nobuo Niimura, Shoichi Kawano, Akira Nonaka, Noboru Y ...
1988 年 57 巻 11 号 p.
3824-3827
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The temperature dependence of the mean-square thermal tensor of KH
2AsO
4 in the paraelectric phase has been investigated by neutron diffraction structure analysis. All the tensor elements except
u22(H) are extrapolated to zero and
u22(H) gives a positive intercept at 0 K. The temperature dependence of the H-site separation, δ, was obtained and was compared with that of KH
2PO
4. The result is well described by the order-disorder behavior of hydrogen.
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Shin-ichi Nakashima, Yasuhiro Nakakura, Atsuo Wada, Karl Kunc
1988 年 57 巻 11 号 p.
3828-3837
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Long period SiC polytypes exhibit a number of Raman bands which reflect their stacking sequence of atomic planes. The Raman spectra of these polytypes can provide information on the phonon frequencies and vibrational amplitudes in the basic polytype (cubic, zincblende structure). Assuming a zincblende type structure as an approximate structure of SiC polytypes, the relative Raman intensity of folded modes in two SiC polytypes is calculated with several models of lattice dynamics and compared with the observed spectra. In the framework of a simple bond-polarizability model we show how the analysis of intensities can be used to rate different phenomenological models.
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Kazuhiro Hara, Yoshihiro Ishibashi
1988 年 57 巻 11 号 p.
3838-3842
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Evolution of the light scattering and electrical properties of the tungstic acid during the gelation process has been investigated. The scattered light becomes anisotropic and the depolarized scattering grows strong around 2 hours after the beginning of gelation. On the other hand, the resistance shows a steady increase. With the results obtained from the present study, we concluded that the light scattering mechanism changes from the Rayleigh scattering to the Mie scattering with the progress of gelation.
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Shoji Hirokawa, Tomoko Iwasaki
1988 年 57 巻 11 号 p.
3843-3850
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The orientational ordering of guest H
2S molecules is studied using a mean-field theory on the basis of quantum statistical mechanics; it is assumed that the guest system is a quenched one consisting of a normal mixture of ortho and para H
2S, and that the guest molecules which are influenced by a crystalline field, of which strength is estimated from far-infrared spectra, couple with one another via dipolar interactions. A phase diagram based on an effective dipole moment
p is obtained. It shows: If
p=0.800D, a second-order transition between a partially disordered and a disordared phase occurs at
T=15.2 K, and the temperature dependence of the heat capacity well coincides with experiment; if
p<0.778D, no cooperative order is expected.
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Yoshimi Tsuchiya
1988 年 57 巻 11 号 p.
3851-3857
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The molar volume of the liquid Se–Te system has been measured using a high energy γ-ray attenuation method. The thermal expansion coefficient, α
p, deduced from the dependence on temperature of the molar volume has a minimum which shifts to the higher temperature with Se concentration. It has been shown that α
p consists of two parts, one due to the normal expansion effect and the other associated with the structural change in the liquid. The latter has a linear relation with the anomalous part of the specific heat. Discussion is given on a model describing the structural evolution with temperature and/or pressure.
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Hisashi Takenaka, Chisato Ogihara, Kazuo Morigaki
1988 年 57 巻 11 号 p.
3858-3867
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The conduction band tail electron resonance was observed at 2 K in a-Si:H by time-resolved optically detected magnetic resonance experiments, using intense pulsed excitation. The exchange interaction between the tail electrons and the trapped holes at A centres was elucidated by the observation of shift of the A centre
g-value with delay time of the microwave pulse after pulsed excitation. Dynamical processes of radiative and nonradiative recombination are discussed on the basis of the experimental results,
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Fumio Komori, Takayuki Goto, Koh-ichi Wago, Shun-ichi Kobayashi
1988 年 57 巻 11 号 p.
3868-3874
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The Knight shift of
27Al in small Al particles is measured in wide ranges of temperature and magnetic field. The samples with diameters smaller than 240 A are investigated. We observe the change in the hamiltonian symmetry with increasing field as a recovery of spin paramagnetic susceptibility. We also observe the critical magnetic field of superconductivity due to orbital pair-breaking effect.
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Kenji Yonemitsu, Yoshiyuki Ono, Yasushi Wada
1988 年 57 巻 11 号 p.
3875-3886
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Effects of electron correlations are studied in trans-polyacetylene up to the second order with respect to the fluctuations around the Hartree-Fock solution. We present results for a spin soliton, which has a negative spin density due to correlations. It is found that the second-order corrections suppress the dependences of the creation energy, the position of the midgap level and the spin density profile on correlations in the Hartree-Fock approximation, and that the suppression is large when the spin density alternation around the soliton is large. Comparing the present results with recent ENDOR experiments, we find that the observed spin density profile can be reproduced if we take the dimensionless electron-lattice coupling strength λ=0.1, the onsite Coulomb energy
U=1.6
t0 and the nearest-neighbor interaction
V=0.8
t0, with
t0 as the nearest-neighbor hopping integral.
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Katsuma Yagasaki, Tomoko Higa, Takeshi Hiraoka, Yowa Kadena
1988 年 57 巻 11 号 p.
3887-3895
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The electrical resistivity ρ and the Hall resistivity ρ
H of LaAg
1−xIn
x (0<
x<0.7) have been measured and analyzed on the basis of two-band model. The calculated temperature dependence of ρ and ρ
H agree well with the experimental ones. The
s electrons are about 0.2 per unit cell for all
x and change little at the band Jahn-Teller transformation temperature
TM. The
d-hole is in a range of 0.6–0.9 per unit cell and its number changes at
TM. The total
s-electron conductivity is about 30% of all and is very large compared with YZn and heavy rare earth RAg
1−xIn
x (R=Gd, Tb and Dy).
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Yoshitake Ueda, Hiroki Hosoda, Takao Kino
1988 年 57 巻 11 号 p.
3896-3902
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The low-field Hall coefficient
RH0 and transverse magnetoresistance coefficient
Pt0 have been measured in a monocrystalline specimen of zone-refined aluminium quenched from 553 and 573 K. The measurements have been made at 4.2 K with asuperconducting chopper amplifier with a sensitivity better than 5 pV. For vacancies as scattering centres in aluminium, the low-field coefficients have been obtained as
RH0=−2.02×10
−11 m
3·C
−1 and
Pt0=0.45×10
−19 Ω
2·m
2·T
−2. These data are analysed according to the three-group model of Kesternich [W. Kesternich: Phys. Rev. B
13 (1976) 4227]. The scattering anisotropy due to a vacancy is similar to that due to Mn, Zn and Ag atoms, but different from that due to Li, Mg and Si atoms. It is concluded that the scattering potential of a vacancy strongly extends into the interstitial region.
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Kazunari Ohshima, Tetsuo Fujita, Sanshiro Sako
1988 年 57 巻 11 号 p.
3903-3909
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
For deposited layers of Sn fine particles as metal soot evaporated in inert gas, the superconducting critical field
Hc and the transition temperature
Tc were obtained by measuring their dc resistance. The temperature dependence of
Hc is explained with the model of the cubic array of particles coupled through the Josephson junction. The coupling strength between the particles determined in this model decreases with increasing the particle size. This is supported by the thermogravimetric analysis where the thickness of the surface oxidized layer of the particle increases with increasing particle size. The enhancement of
Tc is independent of the coupling between the particles, and depends only on the surface phonons of the particle.
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Naoyuki Harada, Yoshihiro Miyamoto, Teruo Matsushita, Kaoru Yamafuji
1988 年 57 巻 11 号 p.
3910-3919
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Nonsaturated pinning characteristic and elastic and plastic properties of a fluxoid lattice are measured by an ac inductive method for superconducting Nb–Ta tapes with normal Nb
2N precipitates. The interaction distance proportional to a yield strain of the fluxoid lattice is shown to be approximately constant except in the vicinity of the upper critical field, indicating that the fluxoid lattice is stabilized by strong pinning interactions by normal precipitates. The dependence of the pinning force density on the pinning parameters estimated from electron micrographs agrees better with the linear summation theory than the theory of Larkin and Ovchinnikov.
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Fusayoshi J. Ohkawa
1988 年 57 巻 11 号 p.
3920-3931
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
An effective Hamiltonian with auxiliary bosons and auxiliary fermions is proposed to treat the Hubbard Hamiltonian with strong correlation. Auxiliary particles themselves can not describe any real excitations. In particular, the Bose condensation of auxiliary bosons never occurs, and auxiliary fermions have no Fermi surfaces. Real excitations are described by two kinds of pair-excitations of auxiliary particles, such as fermionic and bosonic pair-excitations. Superconductivity in the effective Hamiltonian is nothing but the condensation of Cooper pairs between fermionic pair-excitations, which are formed by the superexchange interaction mediated by auxiliary fermions. The proposed model of superconductivity is consistent with anisotropic-singlet superconductivity previously examined by the present author (Jpn. J. Appl. Phys.
26 (1987) L652.), which is based on the Fermi liquid theory of the Hubbard Hamiltonian.
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Norio Ogita, Masayuki Udagawa, Kenichi Kojima, Kohji Ohbayashi
1988 年 57 巻 11 号 p.
3932-3940
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Motivated by the observation of the close correlation between disappearance of the infrared absorption peak at about 680 cm
−1 and the appearance of high-
Tc superconductivity in (La
1−xM
x)
2CuO
4 (M=Ca, Sr, and Ba), we have measured infrared absorption spectra of (La
1−xSr
x)
2NiO
4 (
x=0.0, 0.01, 0.02, 0.03 0.04, 0.07, 0.10 and 0.15), La
2(Ni
1−xCu
x)O
4 (
x=0.0, 0.20, 0.40 0.60, 0.70, 0.80, 0.85, 0.90, 0.95 and 1.00), and Raman spectrum of La
2NiO
4. No disappearance of the infrared absorption peak at about 680 cm
−1 has been observed in (La
1−xSr
x)
2NiO
4. By assigning the peaks to characteristic lattice vibrational modes, discussions have been devoted to the possible origin of the infrared anomaly.
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Teruo Matsushita
1988 年 57 巻 11 号 p.
3941-3945
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The electric field induced by a fluxoid motion in a longitudinal magnetic field is presented. It is shown that the electric field is not given by the Josephson’s equation
E=
B×
v, but by
E=
B×
v−grad ψ, where
B is the magnetic flux density,
v is the fluxoid velocity and ψ is a scalar function. The scalar function ψ is not an electrostatic potential, since the electric field is caused by the induction and reduces to zero in the static situation (
v→0). The reason for the appearance of the additional irrotational term, −grad ψ, is that
v in this field geometry is a phase velocity directed normal to the Poynting flux.
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Kiyohiro Sugiyama, Fumitoshi Iga, Mitsuo Kasaya, Tadao Kasuya, Muneyuk ...
1988 年 57 巻 11 号 p.
3946-3953
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
High field magnetization and magnetoresistance of YbB
12 are investigated up to 550 kOe at low temperatures with special interest in the semiconductive band gap energy under the field. Very large negative magnetoresistance is found and the system is perfectly metallic around 500 kOe with anomalous increase in the magnetization. The experimental results are explained by introducing the model that the band gap produced by the mixing of the f- and conduction electrons is destroyed by applying the field and the released f-electron gives an anomalous magnetization. The
gJ-value is estimated as 1.9 for the f-level and this means that
Γ8 may be most favourable for the responsible f-electron at the Fermi energy.
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Chiaki Uyeda, Akio Yamagishi, Muneyuki Date
1988 年 57 巻 11 号 p.
3954-3960
発行日: 1988/11/15
公開日: 2007/05/29
ジャーナル
認証あり
A systematic study of liquid oxygen under a high magnetic field is described. It is found that the experimental results of the field-induced transparency are not explained by the simple mean field method even though the magneto-volume effect, which enhances the field-induced transparency, is taken into account. The transparency effect is quantitavely explained by the spin-pair model where two spins of the O
2 molecule pair couple with each other. The conclusion seems to be probable because the optical transition comes from one photon absorption by two ground state (
3Σg−) molecules where the pair interaction may play an important role.
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Akira Narita
1988 年 57 巻 11 号 p.
3961-3972
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The magnetic susceptibilities of Gd monopnictides are calculated numerically for the semimetallic and metallic cases using the various tight binding band structures fitted to the APW result of LaP, and the carrier concentration effects on the spin orderings, θ
p and
TN are investigated in detail, in which θ
p and
TN are the paramagnetic Curie and Néel temperatures, respectively. The contributions to the susceptibilities caused by various scattering processes are analyzed in detail, and the main processes are clarified for the semimetallic and metallic cases. Comparisons with the experiments for Gd monopnictides and GdP–GdS systems are also performed. Our calculations give the best agreement with the experiments in the theoretical works so far carried out, although there are many discrepancies.
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Takehiko Oguchi, Hidetsugu Kitatani
1988 年 57 巻 11 号 p.
3973-3978
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The coherent-anomaly method proposed by M. Suzuki is applied to the spin 1/2 ferromagnetic Heisenberg model to estimate the critical exponents. The effective Hamiltonian method to small-sized clusters for the simple cubic lattice, and the inverse temperature power series expansion of the susceptibility for the face centered cubic lattice are combined with the CAM. Both results show that the CAM is useful for the quantum spin systems.
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Hidekazu Tanaka, Soichiro Teraoka, Eiichiro Kakehashi, Katsunori Iio, ...
1988 年 57 巻 11 号 p.
3979-4003
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
We study ESR modes in the ground states of hexagonal ABX
3-type antiferromagnets with easy-axis anisotropy such as CsNiCl
3, RbNiCl
3, CsMnI
3. Taking a six sublattice model for the spin structure, we investigate the normal modes for the motions of the sublattice magnetizations within the framework of mean field approximation. In general, six kinds of modes are obtained by solving the classical equation of motion, d
Mi⁄d
t=[
Mi×
Hi]. Frequency field diagram is presented. Ground state properties of fields for resonance and line widths of ESR spectra on CsNiCl
3, RbNiCl
3 and CsMnI
3 are reported. Calculated values of resonance fields are in agreement with experimental results. The weak interchain exchange interaction constant
J1 is estimated with good accuracy as
J1⁄
kB=−2.8×10
−2 K for CsNiCl
3 and −7.5×10
−2 K for CsMnI
3.
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Akiyoshi Sekine, Minoru Sumita, Toshio Osaka, Yasuharu Makita
1988 年 57 巻 11 号 p.
4004-4010
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The pyroelectric charge of NH
4Al(SO
4)
2·12H
2O was measured after poling the crystal. It was found that the crystal becomes ferroelectric below the Curie temperature of
Tc=−197°C on warming and has spontaneous polarization of 0.10 μC/cm
2 at −240°C. The complex dielectric constant was measured at various frequencies in a frequency range between 330 Hz and 1×10
6 Hz. The crystal exhibited dielectric relaxation and showed a critical slowing down process of polarization. The observed temperature and frequency dependences of the complex dielectric constant can be well approximated in terms of single relaxation time τ(
T) of the Debye-type. Above the Curie temperature, τ(
T) was well described by the relation τ(
T)=(
h⁄
kB)·(
T−
T0)
−1·exp (
ΔF⁄
kBT) with the activation free energy
ΔF=
ΔF0[1−α(
T−
Tc)]. The values of
ΔF0 and α were estimated to be 1.49×10
−20 and 0.0028 deg
−1, respectively.
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Kiyoshi Deguchi, Hiroyuki Kobayashi, Eiji Nakamura, Hirotaka Yamaguchi ...
1988 年 57 巻 11 号 p.
4011-4020
発行日: 1988/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The complex dielectric constant of hexagonal BaTiO
3(h-BT) along the ferroelectric axis has been measured in the frequency range from 10
3 Hz to 10
9 Hz. It is found that the specimen cooled in a strong d.c. electric field exhibits resonant-type dielectric dispersions around 1 MHz and 300 MHz both in the phase II (222 K>
T>
Tc=62 K) and the phase III (
Tc>
T). The dispersion around 1 MHz does not appear for the specimen cooled without the d.c. electric field. The effect of the field-cooling on these dispersions is discussed in connection with the twin structure expected from a group theoretical consideration. The dielectric anomaly around
Tc diminishes in the damped dielectric constant, indicating that the ferroelectric phase transition in h-BT is closely related to an elastic instability.
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