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- Proceedings of the Physico-Mathematical Society of Japan. 3rd Series
- Proceedings of the Tokyo Mathematico-Physical Society. 2nd Series
- Tokyo Sugaku-Butsurigakukwai Kiji-Gaiyo
- Tokyo Sugaku-Butsurigakkwai Hokoku
- Tokyo Sugaku-Butsurigaku Kwai Kiji
- Tokyo Sugaku-Butsurigaku Kwai Kiji
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Volume 62, Issue 1
Displaying 1-50 of 51 articles from this issue
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S. H. Kim1993 Volume 62 Issue 1 Pages 1-5
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThomson scattering of a classical electromagnetic wave (or unstimulated bremsstrahlung in a magnetic wiggler) by a relativistic electron traveling in the direction opposite to the propagation direction of the wave (or the electromagnetic wave equivalent to the magnetic wiggler) is studied quantum mechanically. Unlike Klein-Nishina scattering which is the scattering of an incident photon, the incident radiation makes the electron wiggle in the transverse direction through numerous multiphoton processes of various order. The explicit scattering formula is derived when the potential amplitude in electron energy of the incident electromagnetic wave is less than the electron rest energy.View full abstractDownload PDF (502K) -
Hajime Nakao1993 Volume 62 Issue 1 Pages 6-9
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIt is shown that the effective temporal damping factor of the spectrum of the Eulerian velocity correlation becomes the function of κ2⁄3t (κ: wave number, t: time) for the duration of Richardson’s four-thirds law in the steady, incompressible, homogeneous and isotropic turbulent flow. In addition, it is shown that this effect is caused by the time dependence of the effective Eulerian characteristic time, and is not contrary to the general understanding that the temporal damping factor of the spectrum of the Eulerian velocity correlation is the function of v0κt (v0: magnitude of the typical flow velocity).View full abstractDownload PDF (367K) -
Iwao Hosokawa1993 Volume 62 Issue 1 Pages 10-13
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe Kolmogorov refined similarity hypothesis for isotropic turbulence is reformulated from a viewpoint of probability. As a result, the probability density function (pdf) of velocity increment across a domain of a certain scale is entirely related to the pdf of dissipation rate averaged over the domain. With the recent experimental evidence that the ratio of velocity increment and (cubic root of) dissipation rate in the same domain is similar to a Gaussian distribution and with some good models for isotropic turbulence, it can be explained that the pdf of velocity increment varies continuously from Gaussian to stretched-exponential as the scale of domains decreases.View full abstractDownload PDF (503K) -
Mitsuo Wada, Yasuharu Yamashita, Akikatsu Sawada, Yoshihiro Ishibashi1993 Volume 62 Issue 1 Pages 14-17
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSSingle crystals of Li1.5Na0.5Ge4O9 are grown by the Czochralski method from stoichiometric melt. It has been found that this crystal shows ferroelectric activity in the a-direction of the crystal axis below Tc=192 K. The spontaneous polarization and the coercive field at 185.5 K are 0.52 μC/cm2 and 1.4 kV/cm, respectively. The dielectric constant of the a-axis shows an anomalous increase at Tc. The Curie constant C is about 9.0×102 K above Tc at 10 kHz.View full abstractDownload PDF (280K) -
Tetsuo Deguchi, Yasuhiro Akutsu1993 Volume 62 Issue 1 Pages 19-35
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe present formulas for the Clebsch-Gordan coefficients and the Racah coefficients for the nilpotent representations (N-dimensional representations with q2N=1) of Uq(sl(2)). We discuss colored vertex models and colored IRF (Interaction Round a Face) models from the nilpotent representations by taking full advantage of the infinite dimensional colored representations of Uq(sl(2)). We construct invariants of trivalent colored oriented framed graphs from the nilpotent representations of Uq(sl(2)).View full abstractDownload PDF (1511K) -
Masao Nomura1993 Volume 62 Issue 1 Pages 36-45
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSQuantized quantum-analog rotation function (QQRF), which the present author introduced previously as quantized version of quantum-analog rotation function, are discussed in detail. It is shown that the QQRF is describable as a coupled pair of basis operators. The QQRF has various symmetries, and its form is preserved under several kinds of transformations. Emphasis is put on expanding a product of QQRF’s as a sum of QQRF’s.View full abstractDownload PDF (843K) -
Taro Nagao, Miki Wadati1993 Volume 62 Issue 1 Pages 46-52
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSOne-dimensional discrete Schrödinger equations (tight binding models) are analyzed from the viewpoint of level statistics. The energy levels of them are identical to the zeroes of the corresponding orthogonal polynomials. The level densities and local level correlations are calculated in the cases related to classical orthogonal polynomials. The level densities are the same as those of the random matrix ensembles which correspond to the same classical orthogonal polynomials. The local correlations of levels show perfect rigidity.View full abstractDownload PDF (749K) -
Nobuhiko Saitô, Akira Shudo1993 Volume 62 Issue 1 Pages 53-63
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe density distribution function or simply distribution function in phase space is considered. It can be shown that if the distribution function tends to a constant (uniform distribution) after a long time, an aged system is attained, where ergodicity holds. The problem lies in the interpretation how the distribution function has a limit and tends to a constant. Ergodicity on tori can be derived, provided that we take the limit as the long-time average of the distribution function. In non-integrable hamiltonian systems the distribution function can be assumed to tend to a uniform distribution in the meaning of weak convergence. The aged system thus attained has the properties of ergodicity, mixing and increase of entropy representing irreversibility. The almost same arguments can be shown to hold for quantal systems as well, where density matrix, Wigner and Husimi functions play the main role. It is suggested that ergodicity and irreversibility in quantal systems are observed in the limit h→0.View full abstractDownload PDF (1393K) -
Kazuhiro Satoh, Yutaka Okabe1993 Volume 62 Issue 1 Pages 64-71
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSNumerical study is done on a critical phenomenon in a neural network model of the McCulloch-Pitts type. Such a net, one of excitable media, consists of “neurons” (binary decision elements) each of which randomly sits on a square lattice and is connected to its four neighbors. When the net is activated locally, the “fire” spreads over from the origin according to the deterministic rule. After transient, a self-sustained mode of excitation (time-periodic firing pattern) is established. It is found that a size of the largest excitation tends to diverge as the excitability of the net is increased (a localization-delocalization transition). Numerically evaluated power-law exponents suggest that the criticality of such transition belongs to the same universality class of the percolation transition.View full abstractDownload PDF (711K) -
Kazuhiro Satoh1993 Volume 62 Issue 1 Pages 72-86
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSAn artificial survival Game for a mass of competing species is introduced and investigated numerically. It is assumed that (1) each species consists of hunting predators. (2) All the species have their own nests to live. (3) They feed on common preys which are distributed in a one dimensional cellular region. (4) Each species randomly attacks a certain number of cells to feed on preys. The evolutional rule of this randomly connected predator-prey network is given in a highly simplified manner as a set of difference equations. An optimizing rule which facilitates the efficiency of the whole system is also included. In spite of its simplicity, this Game is found to exhibit complex behavior, i.e., its long-term behavior is chaotic, or self-organizing, or critical, depending on parameters involved.View full abstractDownload PDF (1584K) -
Michihiro Shibata, Akihiro Taniguchi, Hiroshi Yamamoto, Kiyoshi Kawade ...1993 Volume 62 Issue 1 Pages 87-96
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe level structure of 147Nd has been studied from the decay of 147Pr. The radioactive sources of 147Pr were separated from the fission products of 235U using the on-line isotope-separator KUR-ISOL and chemical separation techniques. A decay scheme has been constructed involving 93 γ-rays and a newly observed 1261.1 keV level. The half-lives of 49.9, 127.8 and 214.6 keV levels were determined to be 1.0±0.3 ns, 0.4±0.1 ns and 4.53±0.06 ns, respectively. Conversion coefficients of 15 transitions were determined. The parities for the levels at 49.9, 127.8, 214.6, 314.7 and 463.5 keV are deduced to be odd. Spins and parities for the 769.3 and 792.6 keV levels are deduced to be 3/2+. The properties of transition probabilities between the low-lying triplet hole states are similar to that of three particle states in the N=85 isotones.View full abstractDownload PDF (1048K) -
Jen-Shih Chang, Kalin Spariosu1993 Volume 62 Issue 1 Pages 97-104
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe study of dust particle charging characteristics under a magneto-plasma has been conducted numerically. The numerical modelling was presented for ion to electron temperature ratio, ε=(Ti⁄Te), from 0.1 to 1, the dimensionless electron gyroradius ratio, βe=Rp⁄RBe, from 0 to 20, and the effective electron, or negative ion, to positive ion mass ratio, aε1⁄2=(Time⁄Temi)1⁄2, from 2×10−3 to 0.8. The numerical results show that the dust particles charging characteristics are not significantly influenced by the existence of external magnetic field when βe<1.View full abstractDownload PDF (802K) -
Kanemitsu Katou, Hiroshi Mamada1993 Volume 62 Issue 1 Pages 105-112
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe radial eigenvalue equations governing the stability properties of global electrostatic drift waves in self-consistently stationary cylindrical plasmas confined by sheared magnetic fields are derived and examined from a new point of view. The dissipative electon drift waves that are not localized near the mode rational surface are shown to be more unstable when the plasma current (which produces magnetic shear) flows in the opposite direction to the mode propagation. The effect of finite magnetic shear on its mode structure is also investigated. The density response of the ion drift waves exhibits the non-Boltzmann like behavior and its ratio to the electrostatic potential increases toward the plasma edge.View full abstractDownload PDF (862K) -
Kiyotaka Hamamatsu, Atsushi Fukuyama, Sanae-I. Itoh, Kimitaka Itoh, Ma ...1993 Volume 62 Issue 1 Pages 113-122
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe relation between RF-driven current and wave helicity is analytically and numerically studied for a tokamak plasma. The helicity conversion ratio from the wave to the plasma is discussed and numerically examined for the waves in the range of ion cyclotron frequency in JT-60 plasma. The wave propagation equation which includes kinetic effects is solved as a boundary-value problem with one-dimensional inhomogeneities. Both the RF helicity-driven current and the RF momentum driven current are calculated. It is shown that the efficiency of the current drive by the wave helicity is small compared with the conventional scheme for the fast wave excitation of the present-day plasma parameters.View full abstractDownload PDF (1110K) -
Heiji Sanuki, Kimitaka Itoh, Sanae-I. Itoh1993 Volume 62 Issue 1 Pages 123-139
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA selfconsistent analysis is discussed to determine the radial electric field and loss cone boundary in torsatron/heliotron plasmas under the influence of nonclassical ion losses. Effects of the loss cone loss, charge exchange loss of fast ions with neutrals, and the bipolar part of anomalous loss are taken into account. Analysis is applied to the NBI heated plasma in the CHS device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses by the orbit loss and charge exchange loss with neutrals make the radial electric field more negative than the value of purely neoclassical calculation. The partition of the injection energy among the shine through, direct orbit loss, charge exchange loss and bulk heating is estimated by using the self-consistent electric field profile.View full abstractDownload PDF (2093K) -
Mamoru Yamashita1993 Volume 62 Issue 1 Pages 140-147
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSTwo kinds of lattices built up step by step to satisfy a certain condition on uniformity are introduced and proved to be self-similar for two series of irrational ratios of concentrations, \sqrt2+1, (\sqrt5+1)⁄2, …, (\sqrtk2+1+1)⁄k, … and \sqrt3, \sqrt2, …, \sqrt(k+2)⁄k, …. Consequently for the golden ratio two different self-similar lattices, the uniform and the Fibonacci ones, exist. The condition is shown to be equivalent to the projection method in which the edge of the strip contains the central point of the integer lattice. The self-similar structures of the uniform lattices presented are studied by the aid of the convergents to continued fraction of the ratio and mediants.View full abstractDownload PDF (784K) -
Takeshi Usuki, Yoshiyuki Shirakawa, Shigeru Tamaki, Shin’ichi Ta ...1993 Volume 62 Issue 1 Pages 148-154
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSA neutron diffraction study on the liquid Bi–Se alloys has been carried out over the wide composition range from Bi2Se3 to pure Bi. An essential feature of the total structural functions is similar to those of pure liquid Bi in the Bi-rich range, suggesting that the additional Se atoms are almost substituted with the Bi atoms and they might form a certain short range order, because of the difference in the electronegativities of the constituents. The Bi–Bi configuration which is close to that of pure liquid Bi still remains in the Se-rich range. The partial structural functions have been estimated from the measured total structural data assuming their concentration independence.View full abstractDownload PDF (834K) -
Hiroyuki Mashiyama, Hironobu Kasano1993 Volume 62 Issue 1 Pages 155-162
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSCrystal structure of LiNH4SO4 was refined in phase II (room temperature) and phase III (190 K) by the use of X-ray diffraction intensity with including hydrogen atoms. The least-squares calculations converged with residual parameter R=0.0362 and 0.0378 for phases II and III, respectively. At room temperature, thermal parameters of hydrogen atoms are large and residual electron density is notable around ammonium ions. This may indicate a partial disorderness of the ammonium ions. In the monoclinic phase III, the calculation was performed with considering the effect of twin domains. In the refined superstructure, ammonium ions with hydrogen atoms are perfectly ordered. Hydrogen atoms link nitrogen and oxygen of sulphate ions.View full abstractDownload PDF (997K) -
Yutaka Aikawa, Katsuhiko Fujii1993 Volume 62 Issue 1 Pages 163-169
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe crystal instability due to anharmonic lattice vibrations is discussed by applying the self-consistent Einstein theory to three dimentional crystal systems. It is shown that there exist a mode connected with the crystal instability which depends on the crystal structure and symmetry. The Lindemann parameter is obtained on the basis of this model, and the results are compared with the experimental data for BCC and FCC metals.View full abstractDownload PDF (537K) -
Tomonori Koda, Hatsuo Kimura, Masao Doi1993 Volume 62 Issue 1 Pages 170-178
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe consider the dynamics of the nematic-smectic A phase transition in a system of parallel hard cylinders. We derive a time evolution equation of the density distribution from a free energy functional truncated at the 2nd virial approximation. When the packing fraction is changed, the stable density distribution is transformed from uniform density (nematic phase) to periodic density wave (smectic A phase). We show that the growth of the smectic A structure involves two kinds of dynamical processes. One is the growth of the amplitude of the density wave, and the other is the growth of the coherent length of the periodic structure. We also investigate the equilibrium density distribution as a function of the packing fraction.View full abstractDownload PDF (885K) -
Fuyuki Shimojo, Hideo Okazaki1993 Volume 62 Issue 1 Pages 179-182
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe low temperature phase transition in Ag2Se is investigated for various sizes of the system by means of a molecular dynamics simulation. It is confirmed that the correct structure of the low temperature phase is orthorhombic and belongs to Pmnb space group. In order to transform successfully to the low temperature phase, it is necessary that more than one MD cell vector is composed of even number times bcc unit cell vector in the superionic phase.View full abstractDownload PDF (529K) -
Shin-ichi Furusawa, Hisaaki Hayasi, Yoshihiro Ishibashi, Akio Miyamoto ...1993 Volume 62 Issue 1 Pages 183-195
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe ionic conductivity of potassium titanyl phosphate (KTiOPO4:KTP) single crystals along the a, b and c-axes has been investigated in detail at the temperature range 300∼1200 K. The anisotropic behavior of ionic conductivity of KTP single crystal can be well explained by the consideration of the conduction paths of the K+ ions and the size of the bottle necks deduced from the crystal structure of the KTP.View full abstractDownload PDF (1171K) -
Shin-ichi Furusawa, Satoshi Miyaoka, Yoshihiro Ishibashi1993 Volume 62 Issue 1 Pages 196-199
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe electric conductivity of AgI with dispersed BaTiO3 particles was measured as a function of particle size of BaTiO3 at temperature range from 30 to 130°C. The conductivity enhancement was observed in the AgI–BaTiO3 system, in which the conductivity shows a monotonic increase with decreasing particle size of BaTiO3 (the particle-size effect).View full abstractDownload PDF (476K) -
Yutaka Kaneko1993 Volume 62 Issue 1 Pages 200-204
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSQuantum mechanical rate constants for hydrogen diffusion in a one-dimensional lattice are calculated by the path integral evaluation of a flux-flux correlation function. The thermal average of the rates over the substrate degrees of freedom is evaluated by a Monte Carlo method. The rate constants, thus obtained, exhibit departures from the Arrhenius law at low temperatures owing to a quantum effect. It is shown that the rates are reduced significantly by the effect of the lattice distortion due to the solution of a hydrogen atom. The influence of the thermal fluctuations on the rates is also investigated.View full abstractDownload PDF (642K) -
Yasunori Kubo, Setsuro Asano, Hisatomo Harima, Akira Yanase1993 Volume 62 Issue 1 Pages 205-214
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe energy-band structures of both paramagnetic (PR) and antiferromagnetic (AF) phases of NdB6 are calculated by the Korringa-Kohn-Rostoker method within the local-density approximation. In the calculations, 4f-electrons are treated as partially filled core states. The band-structure in the AF phase is satisfactorily explained by a folding procedure of the PR counterpart. The Fermi surfaces in the AF phase consist of two sheets, a multiply-connected hole sheet and a multiply-connected electron one. These Fermi surfaces reasonably reproduce the measured frequency branches of the de Haas-van Alphen effect. From the comparison between the calculated and the observed cyclotron masses, it is pointed out that the mass enhancement due to the f-electrons is negligibly small.View full abstractDownload PDF (1380K) -
Transfer-Integral Expansion for the d-p Model of the CuO2 Plane —Ground State of the Undoped System—Mitsuo Kataoka1993 Volume 62 Issue 1 Pages 215-223
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe d-p model of the CuO2 plane is studied by means of the perturbation theory. Our Hamiltonian consists of the full energy terms, i.e., the transfer terms tdp between Cu d and O p orbitals, tpp between the p orbitals, and the on-site (Ud, Up) and intersite (V) Coulomb interactions. The energy of the ground state of the undoped charge-transfer-type insulator, Eg, is expanded in powers of the transfer terms up to their fifth order. The obtained perturbation correction to Eg consists of terms of (tdp)2n(tpp)n′ with integers n(≥1) and n′(≥0). The superexchange interaction J is found to be affected considerably by the presence of tpp. The role of V in the stability of the charge-transfer-type ground state is also clarified. In the light of the obtained results, the ground state of La2CuO4 is discussed by use of the realistic parameter values given by Hybertsen et al.View full abstractDownload PDF (975K) -
Tomi Ohtsuki, Bernhard Kramer, Yoshiyuki Ono1993 Volume 62 Issue 1 Pages 224-238
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe Anderson transition in three dimensional layered systems is investigated in the presence of a quantizing magnetic field perpendicular to the layers. The density of states is calculated. By computing numerically the modulus of the one-body Green’s function, the system size dependence of the exponential decay length of the transmission probability is calculated. It satisfies a one-parameter scaling law. The existence of a metal insulator transition is demonstrated. The mobility edge trajectory, and the critical parameters are obtained. The value of the critical exponent, ν=1.35±0.15, is found to be close to that reported previously for the Anderson model without magnetic field.View full abstractDownload PDF (1695K) -
Nobuhiro Shiotani, Yoshikazu Tanaka, Yoshiharu Sakurai, Nobuhiko Sakai ...1993 Volume 62 Issue 1 Pages 239-245
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe [100], [110] and [111] Compton profiles of vanadium are measured with a momentum resolution of 0.12 atomic units. The observed profiles have fine structures and directional anisotropies. Comparison of the results with the APW band theoretical predictions shows that the band theory overestimates the momentum density at low momenta and underestimates it at high momenta. The theory also overemphasizes the fine structures and the scale of the anisotropies.View full abstractDownload PDF (1008K) -
Teruhiko Mabuchi, Hidemichi Toda, Hideo Yamanaka1993 Volume 62 Issue 1 Pages 246-254
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSLow energy electron loss spectra (LEELS) of alkali halides LiF, NaCl, KCl, KBr, KI, RbBr and CsCl, and alkali-earth halides CaF2 and CaCl2 are measured for primary energies 30 to 900 eV. For K and Ca-halides, there are four loss peaks in the core exciton regions, some of which have not been observed in optical measurements and high energy electron loss spectra. The intensities of these loss peaks are primary energy dependent and decrease with the increase of incident energy. The primary energy dependency is largest for K and Ca-halides and decreases for Rb and Cs, and is almost not observed for Li and Na-halides. These loss peaks are thought to be caused by intra-atomic transitions between localized p-core and d-conduction bands in metal ions.View full abstractDownload PDF (905K) -
Yasunari Kurihara1993 Volume 62 Issue 1 Pages 255-262
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSAn oscillatory behavior of the electrical conductivity tensor component of the quasi-two-dimensional conductors is examined in a lower magnetic field region where an observation of the Shubnikov-de Haas oscillation is not expected. A calculation of the component is carried out with the current vertex corrections in use of Kubo formula, which introduces the transport relaxation time τt in place of the relaxation time τs of the energy excitations of the electrons to it. The ratio τt to τs is evaluated for a specific model of the quasi-two-dimensional organic conductors.View full abstractDownload PDF (788K) -
Magnetic Excitations in Superconducting YBa2Cu3O6+x Crystals Studied by Neutron Inelastic ScatteringMasatoshi Sato, Shinichi Shamoto, Takanori Kiyokura, Kazuhisa Kakurai, ...1993 Volume 62 Issue 1 Pages 263-273
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMagnetic excitation spectra in single crystals of YBa2Cu3O6+x with superconducting transition temperature Tc\simeq66 K (x\simeq0.75) and 90 K (x\simeq0.9) are reported. For excitation energies in the range 25–45 meV, a scan at fixed energy yields a single peak with a large q-width centered on the antiferromagnetic wave vector, (π,π), in agreement with the work of Rossat-Mignod and coworkers. However, in contrast to the results of the latter group, we have not observed, despite significant effort, any q-dependent magnetic scattering in either crystal at energies below ∼20 meV, even at temperatures far above Tc.View full abstractDownload PDF (1489K) -
Takashi Hotta1993 Volume 62 Issue 1 Pages 274-280
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIn order to extract the information on the symmetry of the Cooper pair in high-Tc superconductors, we study non-magnetic impurity effects on the density of states for several pairing states in 2-dim. square lattice. The assumed states are s-, extended s- and d-wave pairing ones. Only when we assume an anisotropic pairing state such as a d-wave pairing, we can explain the experimental results on nuclear spin relaxation rate observed in Zn-doped YBa2Cu3O7−δ.View full abstractDownload PDF (924K) -
Masafumi Sera, Takashi Nishikawa, Masatoshi Sato1993 Volume 62 Issue 1 Pages 281-288
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThermoelectric powers S of La2−xSrxCu1−yMyO4 (M=Zn and Ni) and YBa2Cu3−yZnyO7−δ are measured for various values of x and y. A phenomenological description of the anomalous behavior of S is proposed, based on the electron damping which has an asymmetric form with respect to the chemical potential μ. The Zn doping seems to suppress the anomalous contribution of the electrons to various physical quantities, while the Ni-doping does not.View full abstractDownload PDF (825K) -
Daisuke Shiomi, Masafumi Tamura, Hiroshi Sawa, Reizo Kato, Minoru Kino ...1993 Volume 62 Issue 1 Pages 289-300
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMagnetic properties of a stable organic biradical, meta-phenylene bis(α-nitronyl nitroxide) (m-BNN), have been studied. The molecular ground state is found to be triplet (S=1) by the solution EPR measurements. An X-ray structure analysis reveals that m-BNN crystallizes in a dimeric fashion. Susceptibility of a m-BNN single crystal exhibits anomalous temperature dependence as a result of intermolecular exchange interactions. From an analysis based on the structure of magnetic energy spectrum, unusual gap formation in the m-BNN crystals is deduced. The origin of the gaps is discussed in the light of the peculiarity of Heisenberg integer spins.View full abstractDownload PDF (1695K) -
Isao Harada, Isao Mannari, Makoto Kaburagi, Takashi Tonegawa1993 Volume 62 Issue 1 Pages 301-305
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMagnetization process at zero temperature is studied numerically for an Ising-like magnetic chain diluted with nonmagnetic impurities, which break up a magnetic chain into independent segments with various lengths. Calculations are made of the weighted contributions to the magnetization from each segment. The magnetization curve thus obtained shows successive metamagnetic transitions at lower fields in addition to the metamagnetic transition corresponding to the one in the pure case. These successive transitions are attributed to the instabilities of a single domain wall excitation including end-spin reversal process in various segments consisting of even numbers of spins. The characteristic features of the magnetization curve are consistent with recent experimental results on CsCo1−xMgxCl3 at very low temperatures.View full abstractDownload PDF (692K) -
Yukito Furukawa, Yutaka Nakai, Nobuhiko Kunitomi1993 Volume 62 Issue 1 Pages 306-313
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSInternal field distributions in Au(Fe) spin glass systems were evaluated from hyperfine field distributions obtained by Mössbauer spectroscopy. The internal field distributions of the specimens with 5 to 16.8 at.% Fe, are well expressed by stable distributions; limit distributions for the sum of large number of independent variables, defined in the probability theory. The function form of the stable distribution is specified by a characteristic index. Variation of the characteristic index as a function of the Fe concentration was explained by the fact that magnetic atoms are not randomly distributed in a continuum but are located in the lattice points only, as discussed by Klein.View full abstractDownload PDF (1023K) -
Yukito Furukawa, Yutaka Nakai, Nobuhiko Kunitomi1993 Volume 62 Issue 1 Pages 314-320
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSInternal field distributions of Au(Fe) spin glass alloys were obtained at elevated temperatures by Mössbauer spectroscopy. These distributions with a few exceptions are well expressed by the stable distributions defined in the probability theory. It has been revealed that the alloy at the elevated temperature is in a homogeneous spin glass phase; no coexistence of different magnetic regions.View full abstractDownload PDF (605K) -
Yutaka Nakai, Yukito Furukawa1993 Volume 62 Issue 1 Pages 321-326
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSStable distribution analysis for internal field distribution was performed on 11 specimens of ternary alloy spin glass systems, Au1−x(CryFe1−y)x, with x=0.05 or y=0.6. Assuming two types of 57Fe nuclei with different core polarization hyperfine fields, the internal field distribution was obtained for each alloy. Distributions of each specimen are well reproduced by stable distributions. The characteristic index in alloys with y=0.6 increases with x in the similar way to Au(Fe) alloys. This behavior is explained by the lattice effect, as proposed by Klein. On the other hand, the characteristic index in the alloys with x=0.05 does not depend on y.View full abstractDownload PDF (702K) -
Jong-Gul Yoon, Young Jik Kwag, Yun-Seok Cho, Sook-Il Kwun1993 Volume 62 Issue 1 Pages 327-331
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe dielectric constants of urea-doped thiourea single crystals with different concentrations of impurity were measured. The impurity effects are shown to be significant near Tc and the intermediate commensurate phases of δ=1⁄8 and 1/9. For the urea-doped thiourea of relatively low concentrations, step-wise changes of the dielectric constant near Tc are observed. However, as the impurity concentration increases, step-wise changes near Tc disappear while sharp increase of the dielectric constant still remains. Remarkably, the intermediate commensurate phases are completely suppressed for the highly urea-doped sample. Pinning of discommensurations and suppression of the transitions to commensurate phases by impurities are discussed in conjunction with the experimental results.View full abstractDownload PDF (542K) -
Atsuko Yamaguchi, Tetsuya Tada, Toshiyuki Ninomiya1993 Volume 62 Issue 1 Pages 332-339
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSTemperature and excitation intensity dependence of time-resolved photoluminescence (PL) in hydrogenated amorphous silicon (a-Si:H) are investigated to clarify thermalization processes in the band tail states. Red shift of the PL spectra and changes of the PL decay curves associated with increasing temperature are observed. On the other hand, blue shift of the spectra is found to occur at temperatures of 4–150 K with increasing excitation intensity. These results are explained with variable range hopping of carriers in the localized states.View full abstractDownload PDF (992K) -
Masanobu Haraguchi, Masuo Fukui, Shunichi Muto1993 Volume 62 Issue 1 Pages 340-345
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSWe have measured attenuated-total-reflection (ATR) spectra of GaAs/AlAs superlattice (SL) in the infrared region from 250 cm−1 to 600 cm−1. Around frequencies of GaAs (269 cm−1) and AlAs (362 cm−1) TO phonons, we have found a reduction of reflectance produced by the excitation of surface phonon polaritons, being associated with the fine structures in ATR spectra which stem from the folded optical phonons in the SL. We have moreover evaluated the dielectric parameters of GaAs and AlAs through theoretical ATR spectra fit to experimental ones. It has been found that the collision frequencies of TO phonon in the GaAs and AlAs layers employed here are much smaller than those obtained previously by other researchers.View full abstractDownload PDF (840K) -
Yosuke Kayanuma1993 Volume 62 Issue 1 Pages 346-356
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSResonant scattering of photons by a random array of quantum dots is studied theoretically. The quantum dots are approximated by two-level systems with degenerate excited states, which are distributed randomly over sites of a superlattice with concentration C and are coupled with the electromagnetic fields. The simultaneous equations for the photon Green’s functions are solved by a self-consistent field approximation, which bridges the exact solutions in the both limits C→0 and C→1. It is shown that, as C increases and exceeds a critical value, a stop-band appears in the photon density of state. This indicates the changeover of the character of the resonant interaction from the random Rayleigh scattering of photons to the coherent transfer of polaritons. It is predicted that this phenomenon will be observed in the nonlinear dependence on C of the reflectivity of the sample and in the suppression of the light scattering in the direction normal to the incident light beam.View full abstractDownload PDF (1123K) -
Keiichi Kuboyama, Kazuhiro Hara, Hirotaka Okabe, Kazumi Matsushige1993 Volume 62 Issue 1 Pages 357-361
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSIn order to investigate the pH-effect on gelation process of tungstic acid, the simultaneous measurements of transmitted-light intensities were carried out for specimens with several different-pH values (pH=1.3∼1.6), prepared by adding different amounts of NaOH aqueous solution into ion-exchanged tungstic acid. The transmitted-light intensity decreased faster, as the pH-value of the specimen became lower. Moreover, it was found that the transmitted-light intensities of the different-pH specimens showed a unique time dependence when the observation time was scaled by t1⁄2 (the time when the transmitted-light intensity became the middle value of the initial and the final intensity). This result indicates that, though the light-scattering mechanism in tungstic acid might change during gelation process, the mechanism of gelation process itself is same irrespective of pH-values. In addition, the critical pH value for the gelation was extrapolated to be 1.71 from 1⁄t1⁄2 vs. pH value curve.View full abstractDownload PDF (537K) -
Haruichi Kanaya, Kazuhiro Hara, Hirotaka Okabe, Seiji Taki, Kazumi Mat ...1993 Volume 62 Issue 1 Pages 362-367
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe dynamical properties of the pressure-induced gelation process of the muscle protein was investigated by observing the evolution of the turbidity spectra in the pressure-jump experiments. In the pressure-induced gelation process, time dependence of the slope of ln (τd) vs. ln λ (τ: turbidity, d: the thickness of the specimen and λ: wavelength) showed quite different behavior compared with the heat-induced one. Namely, as the time passed, the slope once decreased and then increased, suggesting that the depolymerization of F-actin takes place before the gelation process. Also, the surfaces of the pressure-treated products examined with a scanning electron microscope revealed the more smooth structure than that of the heat-induced gel.View full abstractDownload PDF (889K) -
Akira Nakamura1993 Volume 62 Issue 1 Pages 368-369
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
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Hiroshi Takano1993 Volume 62 Issue 1 Pages 370-371
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
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Haruichi Washimi, Isao Katanuma1993 Volume 62 Issue 1 Pages 372-373
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
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Takashi Shirane, Takatsugu Hagino, Yoshitaka Seki, Teruo Bitoh, Susumu ...1993 Volume 62 Issue 1 Pages 374-375
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
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Yorihiko Tsunoda, Kiyoichiro Motoya1993 Volume 62 Issue 1 Pages 376-377
Published: January 15, 1993
Released on J-STAGE: June 01, 2007
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F. Rotthaus, W. Selke1993 Volume 62 Issue 1 Pages 378-379
Published: January 15, 1993
Released on J-STAGE: May 29, 2007
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