Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 50, Issue 12
Displaying 1-40 of 40 articles from this issue
  • Hiroshi Takano, Ayao Okiji
    1981 Volume 50 Issue 12 Pages 3835-3836
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The explanation of the phase diagram of the mixed compounds NiS2−xSex is given with the use of the doubly degenerate Hubbard model. The metal-nonmetal transition in the antiferromagnetic phase can be explained by introducing the intra-atomic exchange interaction.
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  • Michio Midorikawa, Yoshihiro Ishibashi
    1981 Volume 50 Issue 12 Pages 3837-3838
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    A small but distinct jump in thermal dilatation of a superionic conductor RbAg4I5 crystal was found at the cubic-trigonal transition temperature T1=208 K, in addition to a large discontinuity at T2=122 K. The jump observed at T1 provides a direct evidence that the transition is of the first order as is expected from the Landau condition.
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  • Shinji Kawaji, Jun’ichi Wakabayashi, Jiro Moriyama
    1981 Volume 50 Issue 12 Pages 3839-3840
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    T (temperature)- and Ns (electron concentration)-dependence of the Hall conductivity in (0↓+) Landau level of n-channel (001) Si MOS inversion layers at 1.5 K∼12 K in 15 T is analysed based on a mobility edge model. Observations at T≤2.5 K are reproduced by taking into account Ns-dependence of the Landau level width. A possible way to account for observations at T>2.5 K is to take into account T-dependence of the mobility edge.
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  • Yasunori Tominaga, Hisako Urabe
    1981 Volume 50 Issue 12 Pages 3841-3842
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The temperature dependence of the low-lying pure longitudinal optical phonon mode of B2(z) symmetry in KDP has been observed by the backward Raman scattering. These B2(LO) spectra have the under-damped phonon peaks at about 110 cm−1, which are almost temperature independent. This result strongly suggests that the low-lying broad response of y(xy)x Raman spectrum below ∼110 cm−1 is primarily the transverse optical phonon excitation.
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  • Sukeomi Ogi, Yukio Watanabe, Nobuhiko Fujiwara, Masanori Akazaki
    1981 Volume 50 Issue 12 Pages 3843-3844
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    An anomalous swelling of a local magnetic field was observed near the tube axis in the last stage of the implosion phase in a linear theta pinch with no bias field. This characteristic seems not to be explained by the radial plasma oscillation, but the effect of inelastic electron-neutral collision has a possibility of causing the large swelling.
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  • Toshio Okada, Keishiro Niu
    1981 Volume 50 Issue 12 Pages 3845-3846
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Filamentation and two-stream instabilities for a light ion beam (LIB) fusion system are investigated. Stability conditions for these two types of instabilities are derived for propagation through a background plasma. The results are illustrated by plotting stability boundaries for a proton beam propagating in a plasma.
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  • Kazuo Imasaki, Shuji Miyamoto, Tetsu Ozaki, Hisanori Fujita, Sadao Nak ...
    1981 Volume 50 Issue 12 Pages 3847-3848
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Uniform, long and stable plasma channels for the light ion beam transport were formed by the guidance of CO2 laser. The typical required laser energy and applied electric field were 2 mJ/cm−3·mbar and 10 V/cm·mbar, respectively.
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  • Junichi Kanzaki, Shigeru Odaka, Katsushi Arisaka, Sachio Komamiya, Mas ...
    1981 Volume 50 Issue 12 Pages 3849-3858
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Inclusive productions of π0 and η0 were measured at around 90° in the p-nucleon center of mass system of 12 GeV p-Be collisions. The invariant cross-section Ed3σ⁄d3p was given as a function of pt for the two processes.
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  • D. P. Goyal, A. Mozumder, P. K. Sengupta, S. Singh
    1981 Volume 50 Issue 12 Pages 3859-3861
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The distributions of rapidity intervals for pN interactions at 400 GeV have been studied. The study shows that the general features of cluster production do not change significantly as one goes from an energy 200 GeV to 400 GeV. The data further indicate that the threshold energy for the production of clusters heavier than resonances, is around 400 GeV.
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  • Shoji Hirata, Ichiro Matsuzaki, Akihiro Yanagita, Toshiharu Tako
    1981 Volume 50 Issue 12 Pages 3862-3868
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Successive transitions in an AC electric field in cholesteric liquid crystals with negative dielectric anisotropy have been investigated systematically. According to the relations between the frequency of applied AC field and the threshold voltage Vth of successive transitions and between Vth and cell thickness divided by cholesteric pitch DP0 several features are observed. The threshold voltage for the dielectric regime extends to a DC electric regime. Quenching of the conduction regime is observed in a thinner sample cell. Some curious behaviors of the domain corresponding to the dielectric regime are also observed. A new model which can explain the mechanism of successive transitions in conduction regime is proposed.
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  • Kazuo Hida
    1981 Volume 50 Issue 12 Pages 3869-3875
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    A simple lattice model of liquid crystals exhibiting a reentrant nematic-smectic A transition is presented. The qualitative features of the observed transitions are reproduced. A possibility of the direct transition from the low density nematic phase to the high density nematic phase is predicted.
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  • Nobuo Wada, Yoshio Kashima, Taiichiro Haseda, Bruno Morosin
    1981 Volume 50 Issue 12 Pages 3876-3881
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    Two kinds of field-induced spin ordered states (labeled as A and B) in β-Ni (NO3)2·4H2O are studied by measuring the temperature dependence of the specific heats and susceptibilities. The results reveal that the two ordered states behave like the two-dimensional square Ising system. The residual entropies below Tc, 2ScR, measured under the appropriate magnetic field are 0.47×ln 2 under the field H⁄⁄zA and |H|=27.6 kOe and 0.42×ln 2 under the field H⁄⁄zB and |H|=43.7 kOe, where zA(zB) is one of the principal axes of rhombic crystal field DSz2+E(Sx2Sy2) for the Ni2+ ions associated with the A(B)-ordered state. The smaller value for H⁄⁄zB suggests the slightly larger anisotropy of the interactions along the rows and lines in the square lattice for the B-ordered state. The crystal structure of β-Ni(NO3)2·4H2O determined recently is consistent with the above properties.
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  • Tetsuhiko Okamoto, Hironobu Fujii, Tadamiki Hihara, Kohji Eguchi, Tsun ...
    1981 Volume 50 Issue 12 Pages 3882-3887
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Measurements of the magnetization, magnetic susceptibility and NMR have been made for (Co1−xMnx)2P single crystal compounds. The compounds with orthorhombic structure are ferromagnetic for 0.06<x<0.63, ferromagnetic at high temperatures and screw antiferromagnetic at low temperatures for 0.63≤x≤0.73 and antiferromagnetic for 0.73≤x≤0.80. The magnetic moments of MnI and MnII are expected to have about 1 and 3 μB, respectively, from the measurement of NMR. The magnetocrystalline anisotropy constants K1 and K2 are both negative and their absolute values take maxima at x=0.5. The Curie temperatures and saturation magnetic moments for x≤0.5 compounds are briefly discussed with the exchange interaction and the local environment of MnII site.
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  • Mitsuo Kataoka, Osamu Nakanishi
    1981 Volume 50 Issue 12 Pages 3888-3896
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    For the spin systems with both the symmetric exchange interaction (SEI) and the antisymmetric exchange interaction (AEI) (the Dzyaloshinsky-Moriya interaction), the relative stability between the ferromagnetic state (FMS) and the helical spin density wave (HSDW) is discussed phenomenologically. The arguments are made to the spin systems of which the spin structures are described by the spin density S(r) varying slowly with the position r and the SEI is favorable to the FMS. For the 21 types of crystal symmetry with the isogonal point groups having no inversion symmetry, the characteristics of the instability of the FMS are investigated. By use of the Landau free energy obtained for crystals with the isogonal point groups T and O, the magnetization process, the magnetic phase diagram, and the intensity of the neutron diffuse scattering are calculated. A comparison between the calculated results and the experiments on MnSi is also given.
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  • Yoshiko Someya
    1981 Volume 50 Issue 12 Pages 3897-3903
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The phase diagram of a random mixture of two antiferromagnets with competing spin anisotropies (A1−xBx) has been analyzed by extending the theory of Matsubara and Inawashiro, and Oguchi and Ishikawa. In the model assumed, the anisotropy energies are expressed by the anisotropic exchange interactions. According to this formulation, it has been shown that the concentration dependence of TN becomes a function of (Remark: Graphics omitted.), where P, Q=A, B; SP is a magnitude of P-spin, and JPQη is a η component of exchange integral between P- and Q-spin). Further, the phase boundary between an AF phase and an OAF (oblique antiferromagnetic) phase at T=0 K has been shown to be determined by α(≡SBSA), if (Remark: Graphics omitted.) are given. The obtained phase diagrams for Fe1−xCoxCl2, K2Mn1−xFexF4 and Fe1−xCoxCl2·2H2O are compared with the experimental ones.
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  • Kimio Adachi
    1981 Volume 50 Issue 12 Pages 3904-3910
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    Electron spin resonance was measured at 9.40 GHz as a function of temperature in a quasi-one-dimensional Ising-like antiferromagnet CsCoCl3. Observed resonance in the partially disordered phase, TN2\lesssimT<TN1 and its neighborhood is interpreted in terms of ESR due to spins at propagating domain walls in one-dimensional Ising-like antiferromagnet. The theory developed by Shiba and the present author gives a more consistent interpretation of the temperature dependence of the absorption intensity and the angular dependences of the resonance field and the linewidth than the existing theories. Discussion is given in connection with spin-cluster resonance.
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  • Norikatsu Yamada, Yoshitomo Karaki, Nobuo Wada, Kiichi Amaya
    1981 Volume 50 Issue 12 Pages 3911-3918
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The magnetic phase transition is studied by the AC susceptibility and the specific heat measurements in NaNi triacetylacetonate benzene which is considered as an example of an antiferromagnetic triangular Ising lattice. The magnetic phase transition from paramagnetic to ferrimagnetic state is observed at the temperature Tc0≅32.5 (mK) by the AC susceptibility measurements. The H vs T phase diagram is obtained giving the extrapolated value of Hc0≅320 (Oe) at T=0 K. At Tc0 the susceptibility does not diverge to infinity, and below Tc0 it increases with decreasing temperature. This new type of behavior of the ferrimagnetic transition is qualitatively well described by the antiferromagnetic triangular Ising lattice model.
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  • Yûichi Tazuke, Hidekazu Tanaka, Katsunori Iio, Kazukiyo Nagata
    1981 Volume 50 Issue 12 Pages 3919-3924
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Susceptibilities of single crystals of CsCuCl3 are measured in 4.2 K<T<500 K for Hc and H⁄⁄c. Behaviors characteristic to a one-dimensional Heisenberg ferromagnet with weak interchain interactions are observed. The behaviors are analyzed by the high temperature expansion approximation, and intrachain and interchain exchange interaction constants, J0 and J1, are estimated. The results are, J0k=(24±3) K and J1J0=−0.16±0.04. A discontinuity in the susceptibility arising from a Jahn-Teller cooperative phase transition are observed at Tt∼420 K. The discontinuity is due to a change in J0 at Tt. Relation between the phase transition and the change of J0 is discussed.
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  • Yoshiaki Chiba, Taturu Yosida, Muneyuki Date
    1981 Volume 50 Issue 12 Pages 3925-3931
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Electron spin resonance of Co2+ ion in yttrium aluminum garnet is investigated and three kinds of Co2+ spin sites are found. Most of the Co2+ ions occupy the octahedral site with g⁄⁄=6.470 and g=3.050 and the tetrahedral site spins with g⁄⁄=2.446 and g=2.176 are also found. Other complex spectra are attributed to the interstitial Co2+ spin respnance with gx=1.94, gy=3.80 and gz=5.57. There are 24 magnetically-inequivalent interstitial sites and the observed lines are satisfactorily assigned by this model.
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  • Hikaru Terauchi, Kiyoshi Sakaue, Moritaka Hida
    1981 Volume 50 Issue 12 Pages 3932-3936
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    The X-ray diffraction profiles of the ω-phase in Ti1−xMox, 0.07≤x≤0.20, are carefully examined for the first time. The intensity distribution near the wave vector q0=(2⁄3, 2⁄3, 2⁄3) is asymmetric. The ω-phase appears in rod shaped clusters along the ⟨111⟩ direction in the body-centered-cubic lattice. The incommensurate diffuse scattering can be detected above the critical composition xc=0.10. The scattering profiles are almost independent of temperature over a temperature range −120°C to 50°C. The observed diffuse scattering is discussed in terms of the planar displacements described by a stacking soliton and the coherency of the ω-phase domains.
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  • Masahiro Matsumura, Naokatsu Sano, Tadashi Taniguchi, Kunisuke Asayama
    1981 Volume 50 Issue 12 Pages 3937-3943
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    Knight shift, K, nuclear spin-lattice relaxation time, T1, and spin echo decay time, T2, at various sites have been measured for SnMo6Se8, PbMo6Se8 and PbMo6S8. K shows little change in the superconducting state from the value of normal state, which implies the remaining of the spin susceptibility of conduction electrons in the superconducting state. The density of state at the Fermi level is evaluated from T1 in the normal state. The agreement of the results with the recent band calculation is satisfactory except for Se site, where the experimental result suggests larger density of state. The superconducting energy gaps are about 3.5 kBTC(0) for all sites. Not only d-electrons of Mo but s- or p-electrons of Sn, Pb and Se atoms take part in the superconductivity. T2 for all sites decreases with the onset of the superconductivity. This may be attributed to the conversion of the indirect coupling between like spins to the unlike ones effectively owing to the field inhomogeneity due to vortices.
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  • Jiro Yamashita
    1981 Volume 50 Issue 12 Pages 3944-3951
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    Two kinds of the potential are used for the APW calculation of metallic lithium. The one is the Seitz potential and the other is the Xα-potential. The shape and the size of the Fermi surface, the Fermi velocity, the wave functions and the matrix elements of the electron-phonon interaction are calculated by APW. By using these data and the empirical force constants in the Born-von Karman model, we have carried out the first principle calculation of the temperature dependence of the electrical resistivity, the Hall coefficient, the thermoelectric power at the normal volume and the volume dependence of the resistivity. The theoretical results are in good agreement with experimental values.
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  • Ven-Chung Lee, How-Sen Wong
    1981 Volume 50 Issue 12 Pages 3952-3955
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    The electronic structure of the ZnS(110) surface is studied by the LCAO method. We have studied the surface band structure over the surface Brillouin zone in some detail.
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  • Toshihisa Yamaguchi, Katsumi Hamano
    1981 Volume 50 Issue 12 Pages 3956-3963
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The complex piezoelectric constants, d21, d22 and d23, of ferroelectric AgNa(NO2)2 have been measured by two quasi-static methods; one is the optical interferometric method and the other is based on a comparison with the piezoelectric constant of quartz. The measurement covered the temperature range from 40°C to −80°C and the frequency range from 5 Hz to 50 kHz. All d2j’s show dispersion of the Debye type, d2j(ω)=d2j(∞)+[d2j(0)−d2j(∞)]⁄(1+iωτ). The relaxation time, τ, which is of the order of 5×10−6 sec at room temperature coincides with the dielectric relaxation time and shows critical slowing down toward Tc (37°C). It has been found that the dipolar contribution, [d2j(0)−d2j(∞)], and the ionic and electronic contribution, d2j(∞), are of opposite signs to one another and the static piezoelectric constant, d2j(0), changes its sign at some temperature in the ferroelectric phase.
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  • Yukikuni Akishige, Tutomu Kubota, Kikuo Ohi
    1981 Volume 50 Issue 12 Pages 3964-3971
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    The electron spin resonance of Fe3+ ion in Sr2Nb2O7 single crystal has been studied in the ferroelectric normal phase. The main ESR line is associated with |±1⁄2⟩ transition of Fe3+ ion in one of two distorted NbO6 octahedra. The angular dependence of the ESR line can be fitted with the crystal field parameters obtained from the third-order perturbation: |D|=0.50 cm−1 and |E|=2.36×10−2 cm−1. The calculation based on the superposition model shows that the sign of D is positive and Fe3+ ion sites on near the center of the octahedron rather than the position of Nb ion.
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  • Masaru Kasahara, Itaru Tatsuzaki
    1981 Volume 50 Issue 12 Pages 3972-3976
    Published: December 15, 1981
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    Light scattering spectra of mixed crystals KDP1−xDKDPx with x=0.08, 0.04 and 0.0 (KDP) are measured by a Fabry-Perot interferometer with a free spectral range of 8 cm−1. Spectra are analyzed with the Debye type susceptibility of a polarization fluctuation coupled to an acoustic phonon. The relaxation times of an isolated dipole for x=0.08, 0.04 and 0.0 are found to be 0.27, 0.21 and 0.15 in the unit of 10−12 sec, respectively.
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  • Hikaru Terauchi, Kazuhiro Tanabe, Hironobu Maeda, Moritaka Hida, Nagao ...
    1981 Volume 50 Issue 12 Pages 3977-3979
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The Fourier transform of EXAFS curve of PbTiO3 in an amorphous state has been determined. That of crystalline state has also been obtained and the effect of annealing the amorphous specimen has been studied.
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  • Kazutaka Sato, Akira Sugiyama
    1981 Volume 50 Issue 12 Pages 3980-3987
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    A dislocation in a material of high Peierls barrier moves in a direction of an external force by successive formation of a new pair of kinks and by propagation and annihilation of the kinks. Dislocation velocity depends on a formation rate and on a propagation velocity of the kinks. A computer simulation gives that the moving dislocation is not a straight line but is distributed over many Peierls valleys containing many kinks. It also gives that, 1) an average dislocation velocity is approximately proportional to the geometric mean of the formation rate and the propagation velocity, and 2) the distribution of dislocation segments is not truly stationary but quasi-stationary within the time of a present computation. A new treatment of the average dislocation velocity reproduces results given by the computer simulation approximately.
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  • Kazuo Soda, Noriaki Itoh
    1981 Volume 50 Issue 12 Pages 3988-3995
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    Measurements were made of the absorption change at the F band and of the singlet luminescence in NaCl, induced by photoexcitation of the lowest state of the triplet self-trapped excitons into excited states higher than the lowest state by 1.7 eV∼2.8 eV. It is found that excitation with photons below 2.5 eV causes both the F-center creation and the σ-luminescence, while excitation with photons above 2.5 eV causes only the σ-luminescence. These results indicate that non-radiative transition from the higher excited states to the lowest state of the self-trapped exciton is selective. The cause of the selectiveness is discussed. The yield of the F center creation at the higher excited state of the self-trapped exciton was found to be about 10−2. The stability of the created F centers in NaCl is found to be lower than in other alkali chlorides.
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  • Hiromu Ueba, Shoji Ichimura
    1981 Volume 50 Issue 12 Pages 3996-4005
    Published: December 15, 1981
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    Fano’s treatment for the interaction between a discrete level and a continuum state is used to calculate the eigenstates of molecules adsorbed on a metal surface, where both surface plasmon and electron-hole pair excitations due to the Coulomb field of the molecular dipole are taken into account. Spectral density of states of adsorbed molecules shows more broadened structure than that calculated by a simple image dipole model. The role of electron-hole excitations on the Raman scattering of adsorbed molecules is then investigated.
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  • Masataka Mizushima
    1981 Volume 50 Issue 12 Pages 4006-4012
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    It is shown that Zener’s theory of adiabaticity is applicable to find the probability of photon absorption (or emission) by molecules. In contrast to the conventional approach based on Dirac’s time dependent perturbation theory, in which the broadening of spectral lines is of secondary importance, the present theory shows that spatial inhomogeneity produced by intermolecular potentials is vitally important in the radiation processes. Our results agree with the established parts of the conventional theories, but some new effects are also predicted.
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  • Hirohumi Sakashita, Nobuhiko Ohama, Atsushi Okazaki
    1981 Volume 50 Issue 12 Pages 4013-4021
    Published: December 15, 1981
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    The lattice constant of KMnF3 has been measured by means of the high-angle double-crystal X-ray diffractometry (HADOX). The relative accuracy of the lattice constant to one part in 106 is attained. The value of the critical exponent β for the static rotation angle of MnF6 octahedra below the structural phase-transition temperature (186.65 K) is determined to be 0.2857±6 from the lattice constant a(T); the value is significantly smaller than 0.38 predicted for a 3D-Heisenberg system and even than 0.315 for a 3D-Ising system, with an isotropic short range interaction. This suggests that the transition occurs in the vicinity of a tricritical point. The lattice constants themselves also exhibit a critical behaviour; the value of the critical exponents are 2β for a(T) and β for c(T).
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  • Masanori Hidaka, Shigeru Yamashita, Kiyoshi Inoue, Noboru Tsukuda, B. ...
    1981 Volume 50 Issue 12 Pages 4022-4029
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The successive structural phase transitions of CsVF4 have been studied by means of polarizing and electron microscopes. A new phase in the temperature range 240°C to 250°C has been found. It became clear that the transitions at 152°C, 240°C and 250°C have the character of the first ordering on account of the co-existence of two phases near the transitional point. Then, a notation of each phases is as follows: Phase I (≥250°C), II (240≤ ≤250°C), III (152≤ ≤240°C) and IV (≤152°C). From the results of electron diffraction, the satellite and the diffuse reflection, observed by electron diffraction, are interpreted in terms of an oscillation of the VF6 octahedra about the principal axes of the idealized structure.
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  • Motoshi Uchiyama, Chikara Ishii
    1981 Volume 50 Issue 12 Pages 4030-4034
    Published: December 15, 1981
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    A stable structure of cholesteric liquid crystal thin film in a magnetic field is explored under the boundary condition that the film is strongly anchored at one surface and kept free at the other. It is shown that the system shows a series of first order phase transitions. A step-wise change of helical pitch is obtained as a function of external magnetic field.
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  • Kazunari Ikuta
    1981 Volume 50 Issue 12 Pages 4035-4038
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    Ablation acceleration of macroparticle along field lines in a spiral magnetic field is considered in detail in order to give the accelerated body a spin.
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  • Teruo Saito, Shin Kubo, Masahiko Nakamura, Yasuji Hamada, Shigetoshi T ...
    1981 Volume 50 Issue 12 Pages 4039-4046
    Published: December 15, 1981
    Released on J-STAGE: June 01, 2007
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    A submillimeter wave scattering method was used to study low frequency, small scale, density fluctuations in plasmas and we have observed a microturbulence in a range of drift waves in the WT-1 and 2 tokamaks. The density fluctuations are very intense (\ ildene⁄\ ildene∼several percent). The wavenumber spectra have a peak at kρs\simeq0.5 and are isotropic in the two-dimensional k plane, where k is the wavenumber perpendicular to the toroidal field BT and ρs=(MTe)1⁄2⁄eBT. The frequency spectra are very broad and the high frequency components are contained in an inner part of the plasma. Further, their intensity decreases and the frequency spectrum becomes narrow when the lower hybrid wave driven current is generated.
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  • Katsunobu Nishihara, Masayoshi Tajiri
    1981 Volume 50 Issue 12 Pages 4047-4053
    Published: December 15, 1981
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    This paper shows that rarefaction ion acoustic solitons appear in a two-electron-temperature plasma. And also it presents general conditions and physical mechanism for existence of the rarefaction solitons. It is found that finite amplitude rarefaction and compression solitons coexist in a plasma within a certain parameter region.
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  • Kyoji Yamamoto, Kenji Watanabe, Shinichiro Yanase
    1981 Volume 50 Issue 12 Pages 4054-4062
    Published: December 15, 1981
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    The stability of a quadruple vortex street, i.e. a pair of double vortex streets in a perfect fluid is investigated for small disturbances. Permanent configurations are first determined; two of which are then examined in their stability—one is a symmetric arrangement of a pair of staggered (Kármán-type) double streets and the other is an antisymmetric arrangement of the pair.
    The stability curves are obtained for several values of ratio of the distance 2b0 between the double streets to the spacing a between consecutive vorticies in a row. It is found that both types are neutrally stable for most of disturbances except unstable disturbances in very narrow ranges of a parameter specifying the disturbances mode, provided that b0a\gtrsim0.5 and ba is taken to be about 0.28, where b is the breadth of the double street. The symmetric type is more stable than the antisymmetric one.
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  • Moon-Uhn Kim
    1981 Volume 50 Issue 12 Pages 4063-4067
    Published: December 15, 1981
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    Steady symmetric rotation of a disk in an infinitely long circular cylinder is considered on the basis of the Stokes approximation. A series expression in powers of the disk-cylinder radius ratio is obtained for the torque necessary to maintain the rotation. As the ratio approaches to unity, the torque increases logarithmically and the estimate from the series expression is shown to agree well with that from an exact asymptotic theory.
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  • Hidenori Hasimoto
    1981 Volume 50 Issue 12 Pages 4068-4070
    Published: December 15, 1981
    Released on J-STAGE: May 29, 2007
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    The axially symmetric flow problem due to a stokeslet situated along the symmetry axis through a circular hole in a rigid plane wall is examined. Concise expression for the solution in terms of the Green function is obtained. The singularity in the solution of the basic equation presented by Davis et al. (J. Fluid Mech. 103 (1981) 183) is pointed out and removed with a slight modification of their results.
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