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Yuhji Kuroda
1991 年 60 巻 3 号 p.
727-730
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
We investigate a singular Poisson bracket which appears in Hamiltonian fluid mechanics. It is shown that we can get the most general Casimir for such systems by solving the functional equations which correspond to zero eigenvalue equations. Especially, in the case of a three-dimensional adiabatic perfect fluid, the most general Casimir is shown to be the generalized enstrophy only.
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Shozo Takeno, Shigeo Homma
1991 年 60 巻 3 号 p.
731-734
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
A study is made on a solitonlike entity in a one-dimensional disordered nonlinear lattice described by a discrete version of the nonlinear Schrödinger equation with nonlinear intersite coupling. The model equation is an extension of equations in the localization theory to the nonlinear regime, where on-site frequencies are random variables. By analytical calculations, two types of nonlinear states are shown to exist, one is a stationary self-localized nonlinear mode and the other a solitonlike mode satisfying a local dispersion relation in the disordered system for small fluctuations. The results of numerical experiments show two features: a fairly smooth propagation of a soliton and its settling down to stationary nonlinear localized modes for small and large fluctuations, respectively.
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Koichi Saeki, J. Juul Rasmussen
1991 年 60 巻 3 号 p.
735-738
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
A stationary solution of the coupled state between an electron hole and an ion soliton (CHS) is found in a Vlasov plasma. The CHS is accelerated to markedly high speed exceeding that of the normal ion acoustic soliton owing to the electron hole.
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Minoru Fukui, Taturu Yosida
1991 年 60 巻 3 号 p.
739-741
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Phase transition of nickel propylenediamine nitrite perchlorate Ni(C
3H
10N
2)
2NO
2ClO
4 (NINO) has been studied by the DSC method, and a new structural phase transition has been observed at about 376.5 K. The phase transition is of the first order with the transition enthalpy of about 20.2 J/g. The crystal symmetry suggests that the room-temperature phase is electrically polar (ferroelectric, ferrielectric or pyroelectric).
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Sadao Nakajima
1991 年 60 巻 3 号 p.
742-744
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
The possibility of a new theoretical approach to strong electron correlation in solids is shown by applying it to the lowest-order calculation of hopping energy of the single hole doped into the Mott-Hubbard insulator, with the result that the hopping is appreciable even in the antiferromagnetic state if zero-point spin wave fluctuations are taken into consideration.
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Shin-ichi Kimura, Hisatomo Harima, Takao Nanba, Satoru Kunii, Tadao Ka ...
1991 年 60 巻 3 号 p.
745-748
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
The joint densities of states (JDOS) of LaB
6 were calculated by using the result of the band structure with different 4
f-level positions and compared with the optical conductivity spectrum (σ(ω)) due to the interband transition from 2 eV to 22 eV for the purpose of confirming our previous assignment on the origin of the peaks resolved in σ(ω) and of checking whether the band model is applicable in the present systems. It was found that the peaks at 7 eV and 9 eV in σ(ω) were due to the transition from B-2
p to La-5
d and that at 3.5 eV in σ(ω) was due to the transition between B-2
p bonding and antibonding states and its exciton.
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Atsunobu Nakamura, Yukio Maki, Ayao Okiji
1991 年 60 巻 3 号 p.
749-752
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
We calculate the wave functions of the stationary states for the geometry of the semi-infinite two-dimensional region with a narrow channel as a first step in the investigation of the behaviour of the electron waves around the injector. In the presence of a magnetic field, we obtain a periodic peak structure in the modulus squared of the wave function along the boundary in the semi-infinite two-dimensional region, the period of which is nearly equal to the classical cyclotron diameter. Moreover, it is shown that small peaks exist between the periodic main peaks, which is considered to be one of the characteristic aspects of the quantum interference effects.
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Toshio Mizushima, Yosikazu Isikawa, Akihiro Maeda, Kazunori Oyabe, Kat ...
1991 年 60 巻 3 号 p.
753-756
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Experiments of electrical resistivity, specific heat and magnetic susceptibility of a ternary intermetallic compound CeNiAl
4 have been carried out. It is found that CeNiAl
4 is a new member of the dense-Kondo compounds in the valence-fluctuation regime and that CeNiAl
4 is nonmagnetic above 1.6 K. The susceptibility χ
0 and the electronic specific heat coefficient γ
0 which are extrapolated to 0 K are 5.6×10
−3 emu/mol and 204 mJ/mol·K
2, respectively. The Kondo temperature
TK is estimated to be 67 K or 86 K.
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Noriaki Sato, Masaki Kagawa, Katsunori Tanaka, Naoya Takeda, Takeo Sat ...
1991 年 60 巻 3 号 p.
757-759
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
We have newly found and succeeded in growing a mass-enhanced ferromagnet U
2PtSi
3. The electronic specific heat coefficient is 200 mJ/K
2 per mole of U. The magnetization shows no saturation up to 80 kOe for both the
a- and
c-axes. The magnitude of remanence is much smaller compared with the effective moment in the paramagnetic phase. Experimental results on single-crystalline samples are presented and discussed.
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Minoru Takahashi, Tôru Sakai
1991 年 60 巻 3 号 p.
760-763
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
The shape of the magnetization curve of the
S=1 Heisenberg antiferromagnet at zero temperature is discussed. It is found that the magnetization behaves as \sqrt
h−
hc at the beginning of magnetization as a function of external field
h. The transverse correlation function 〈
S0xSnx〉=〈
S0ySny〉 of this system decays algebraically at zero temperature when it is partially magnetized by the field to the
z-direction (〈
S0xSnx〉\simeq(−1)
nn−η). The exponent η is 0.3∼0.5. This exponent can be calculated by the Luttinger liquid assumption and diagonalization results of finite chains. This is in contrast to the exponential decay of this chain in zero field.
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Hiroki Yamazaki, Yoshitami Ajiro, Nobuyoshi Hosoito, Teruya Shinjo
1991 年 60 巻 3 号 p.
764-767
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
A series of evaporated Fe(30 Å)/Au(
d Å)/Fe(10 Å) trilayers with various Au interlayer thicknesses from 10 to 120 Å is investigated by means of ferromagnetic resonance (FMR) technique at 300 K. Exchange coupling between Fe layers accounts for the change of FMR spectra. Comparison of the calculated and the observed resonance field values yields a coupling parameter
J as a function of
d. For
d≤18 Å, the exchange coupling is strongly ferromagnetic. Antiferromagnetic coupling is realized for 75<
d<85 Å.
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Makoto Okusawa, Kazuo Soda, Tamiko Mori, Takehiko Ishii
1991 年 60 巻 3 号 p.
768-771
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Photoelectron spectra have been measured on RbF in the photon energy region where 3
d electrons of the Rb
+ ion are excited. Two features appearing on the high-binding-energy side of the Rb
+ 4
s line and previously assigned to the configuration-interaction satellite and the energy loss of excited electrons are resonantly enhanced by excitations above the threshold of the 3
d electron of the Rb
+ ion, but the Rb
+ 4
s line itself is not. This fact shows that the configuration interaction is not important for the feature previously assigned to the satellite and that the origin of the feature previously assigned to the extrinsic energy-loss peak is inherent in the photoexcitation process. The features are assigned tentatively to complexes composed of two core holes with a trapped electron.
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Kozo Okada, Akio Kotani
1991 年 60 巻 3 号 p.
772-775
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
A cluster model approach is applied to the analysis of the Ni 2
p core-level X-ray photoemission spectra (XPS) in Ni dihalides, where the intraatomic multiplet coupling is fully taken into account. The difference in the line shape between the 2
p3⁄2 and 2
p1⁄2 spectra is shown to originate from the multiplet splitting of their charge transfer satellites.
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Tôru Moriya, Yoshinori Takahashi
1991 年 60 巻 3 号 p.
776-779
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
The optical resistivity due to antiferromagnetic spin fluctuations in two-dimensional metals, as a possible model for high
Tc oxides, is calculated within the Born approximation and the self-consistent renormalization (SCR) theory for the spin fluctuations. The result is shown to explain the observed anomalous behavior of optical conductivity in YBa
2Cu
3O
7 above
Tc quantitatively.
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J. Awrejcewicz, Tsuneo Someya
1991 年 60 巻 3 号 p.
781-784
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
An analytical condition for the existence of two-parameter family of periodic orbits in an autonomous dynamical system is developed. This condition is based on asymptotic and averaging methods, where two independent perturbation parameters are applied.
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J. Awrejcewicz
1991 年 60 巻 3 号 p.
785-788
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
A numerical technique (based on solving a boundary value problem) is used to trace a route to chaos via period doubling, and to obtain the parameter set of sudden transition to chaos. Results are compared with those found by approximate analytical methods.
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Masao Nomura
1991 年 60 巻 3 号 p.
789-797
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Concepts of invariants, co-variant and contra-variant tensors of quantum group
Uq(
sl(2)) are settled in relationship to
q-deformed representation matrices. The formalism is used to exploit a
q-deformed van der Waerden method for quantum Clebsch-Gordan coefficients. Difficulties inherent in a
q-deformed van der Waerden method given by Ruegg are overcome.
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Ryogo Hirota, Yasuhiro Ohta
1991 年 60 巻 3 号 p.
798-809
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Solutions to a hierarchy of coupled bilinear equations,
(
D14−4
D1D3+3
D22)τ·τ=24\barσσ,
(
D13+2
D3+3
D1D2)σ·τ=0,
(
D13+2
D3−3
D1D2)\barσ·τ=0, …,
are expressed by two types of pfaffians. The first expression is τ=(0, 1, …, 2
N−1), σ=(0, 1, …, 2
N−3), \barσ=(0, 1, …, 2
N+1) where (
l,
m) elements are characterized by the differential rules, (∂⁄∂
xn)(
l,
m)=(
l+
n,
m)+(
l,
m+
n). The second one is τ=(1, 2, …, 2
N), σ=(
c1,
c0, 1, 2, …, 2
N), \barσ=(
d0,
d1, 1, 2, …, 2
N), where (
i,
j) elements are given by (
i,
j)=
cij+∫
x1(
figj−
fjgi)d
x1,
cji=−
cij, (
dn,
i)=(∂
n⁄∂
x1n)
fi, (
cn,
i)=(∂
n⁄∂
x1n)
gi, (
dn,
dm)=(
cn,
cm)=0, where
fi and
gi satisfy the linear differential equations, (∂⁄∂
xn)
fi=(∂
n⁄∂
x1n)
fi, (∂⁄∂
xn)
gi=(−1)
n−1(∂
n⁄∂
x1n)
gi. In special cases, these solutions are reduced to the solutions of the KP and BKP hierarchies.
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Nobuo Furukawa, Masatoshi Imada
1991 年 60 巻 3 号 p.
810-824
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
The minus sign problem, as a problem of the non-positive-definite measure of the path integrals, is examined in the Monte Carlo simulation of the Hubbard model. A new correction method in terms of the ratio of two measured quantities is proposed to calculate physical properties. The momentum distribution and the spin correlation as well as the energy in the ground state are tested against the exactly diagonalized results. The results show that this ratio correction method is a promising prescription to reduce the minus sign problem.
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Tohru Kawarabayashi, Masuo Suzuki
1991 年 60 巻 3 号 p.
825-832
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Scalar chiral orders in the two-dimensional Heisenberg model with frustration are investigated using the super-effective-field theory. The present numerical results suggest that no chiral phase transition exists in this system, because correlations of scalar chiral orders are too small for it to occur.
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Il-Tong Cheon
1991 年 60 巻 3 号 p.
833-835
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
A study has been done on the possible frequency shifts of the γ-ray emitted from a nucleus placed in a finite space formed with two parallel conducting plates separated by a distance
b from each other. These shifts are estimated as order of magnitudes, 10
−8∼10
−9 eV with
b=1 mm for the gamma transition of
121Sb and
133Cs from the first excited states to the ground states.
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Kunitaka Kondo
1991 年 60 巻 3 号 p.
836-844
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
A method of the event reconstruction based on the parton level dynamics is formulated. Formulae for the mass probability are given for the 2→2 processes where 0 or 1 missing particles per channel are included in the final states. Uncertainties of the final parton momenta and their propagation to the reconstructed intermediate states are integrated into the formulation. An application to analysis of the top quark pair production with standard decay modes is discussed.
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Suguru Muto, Susumu Ohya, Kazuhiko Heiguchi, Naoshi Mutsuro
1991 年 60 巻 3 号 p.
845-849
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Nuclear magnetic resonances of oriented
137m,gCe and
139Ce in an iron host have been measured at 7 mK. From the resonance-shift measurement of
137mCe, the magnetic hyperfine splitting frequency ν=|μ
BHF⁄
Ih|, the magnetic moment μ and the magnetic hyperfine field
BHF were derived as ν=54.25(1) MHz, |μ(
137mCe, 11⁄2
−)|=1.01(4)μ
N and
BHF(
137CeFe)=−38.8(10) T, respectively. The resonance frequencies of
137gCeFe and
139CeFe at the external field of 0.2 T were found to be 188.3(5) and 208.5(5) MHz, respectively. With the measured hyperfine field, the magnetic moments of
137gCe and
139Ce were deduced as |μ(
137gCe, 3⁄2
+)|=0.96(4)μ
N and |μ(
139Ce, 3⁄2
+)|=1.06(4)μ
N. The measured magnetic moments are compared with the theoretical values based on the core-polarization model.
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Keiji Kosaka, Katsumi Yonei
1991 年 60 巻 3 号 p.
850-861
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
A difficulty is pointed out about the eigenvalue condition of the relativistic WKB method proposed by Good [Phys. Rev.
90 (1953) 131]. To overcome this difficulty, an alternative WKB eigenvalue condition is derived, based on the same idea as that used by Goldberg
et al. [Phys. Rev. A
39 (1989) 506] for continuum problems of an electron in screened Coulomb potentials. A detailed numerical examination indicates that the newly obtained WKB eigenvalue condition yields a good approximation to the exact eigenvalues. As an application of practical use, one-electron energies of atoms and positive ions are evaluated using effective potentials determined from the relativistic Thomas-Fermi-Dirac-Weizsäcker model proposed by Tomishima [Progr. Theor. Phys.
42 (1969) 437]. The result is in good agreement with the relativistic SCF results.
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Atsumu Hirabayashi, Atsushi Ichimura
1991 年 60 巻 3 号 p.
862-867
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Validity of the Franck-Condon approximation is experimentally examined for electron-impact excitation of the C
3Πu state of N
2 molecule. The relative excitation cross sections for associated vibrational levels up to υ=4 at an electron energy of 48 eV are derived with measuring the emission band intensities of the second positive system. The result is compared with the prediction by the approximation, and appreciable discrepancies are found between them. In particular, the ratio σ
υ=3⁄σ
υ=0 of the cross-sections obtained is by about a factor of two larger than the corresponding ratio of the Franck-Condon factors.
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Shigeo Sasaki
1991 年 60 巻 3 号 p.
868-878
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Drag reduction behaviors of xanthan polysacharide and scizophyllum polysacharide solutions are presented. The friction factor relation of 1⁄\sqrt
f=4.0·log (
Re·\sqrt
f)−0.4+δ is observed for solutions of polymers having long persistent lengths, where
f·
Re and δ are a Fanning friction factor, a Reynolds number and a constant, respectively. On the other hand, the relation of 1⁄\sqrt
f=(4.0+
D)·log (
Re·\sqrt
f)+A is observed for solutions of polymers having short persistent lengths, where D and A are constants. From concentration dependencies of these relations, the following relations are found;
S+∝
Cp0.75 for the former case and
S+∝
Cp0.75·ln (γ
v⁄γ
v*) for the latter case, where
S+,
Cp, γ
v and γ
v* are a normalized slipping velocity between a viscous sublayer and a Newtonian plug zone, a polymer concentration, a shear rate in the viscous sublayer and an onset γ
v for the drag reduction, respectively. The γ
v* is found to be a monotonically decreasing function of the persistent length. Theoretical comments on the experimental results are also presented.
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A. M. Abd-el-Hafiz
1991 年 60 巻 3 号 p.
879-883
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
The problem of the two phase steady flow in an infinite cylindrical pipe is studied when one of the phases is non-Newtonian. It is found that the velocity flow rate of both Newtonian and non-Newtonian phases are greater than the corresponding values when the two phases are Newtonian but the skin friction on the surface of cylinder is less than its value when the two phases are Newtonian.
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Kiyomasa Watanabe, Yuji Nakamura, Masahiro Wakatani
1991 年 60 巻 3 号 p.
884-895
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Radial electric field,
Er, is obtained by imposing the ambipolar condition or solving the electric field diffusion equation in the transport code for Heliotron E. The latter approach usually gives a little smaller |
Er| than the former one. In the context of neoclassical transport theory toroidal and poloidal ion flow are also calculated and compared consistently with measured ion flow velocities at
r⁄
a\simeq0.7∼0.8 in Heliotron E ECRH experiments. Positive electric field is realized in the low density regime \bar
n\lesssim1×10
19 m
−3 with a high heating power.
Er changes from positive to negative according to the increase of the density. It is pointed out that the edge anomalous transport is essential to obtain the positive
Er in the stationary state, which is different from Kovrizhnykh’s conjecture that
Er is negative or small positive within the neoclassical diffusion theory.
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Yong Kweon Suh
1991 年 60 巻 3 号 p.
896-906
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Aref’s blinking vortex system (H. Aref: J. Fluid Mech.
143 (1984) 1.) is extended to the case when the vortex oscillates harmonically. The equations of motion of the passive particle are given in coordinates suitable for integration. Stirring mechanism could be described by the horse-shoe map in the rotational way not in the linear way. The optimal operating condition for the best stirring exists for the parameter μ (proportional to the vortex strength, the period of the vortex motion and the inverse of the tank area). Merging and splitting between the chaotic regions takes place abruptly near the boundary when the parameters are changed and is responsible for the abrupt change in the chaotic area. The present system gives on the whole the chaotic region smaller than the original system.
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Jun Yamada, Yoshiyuki Uchida, Yoshiaki Hioki, Mineo Sahashi
1991 年 60 巻 3 号 p.
907-912
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
When a high pressure gas was irradiated by a focused ruby laser light, a hot and dense plasma was produced, and moved towards the lens under the action of the laser radiation. The length of the laser-produced plasma was calculated on the basis of a breakdown wave and a radiation supported shock wave processes. The plasma length is experimentally observed in high pressure argon gas up to 200 atm, which agrees with the calculated one. At high pressure, the breakdown wave is dominant, while the radiation supported shock wave is predominant at low pressure.
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Hideshi Fujishita, Shin-ichi Yamagata, Masatoshi Sato
1991 年 60 巻 3 号 p.
913-920
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Crystal Structures of Pb
2Sr
2YCu
3O
8+δ (δ=0 and 1.67) were analysed by X-ray Rietveld method. The sample with δ=1.67 obtained by an oxygen annealing has a tetragonal lattice. The analysis has been made with the assumption that absorbed oxygen atoms occupied the sites in the oxygen deficient Cu layer. We used the space group P4/mmm. The analysis of the sample with δ=0 obtained by a quenching shows almost the same structure as the one presented previously. However, introduction of slight monoclinic distortion was found to give much better fit to the observed profile. The distance between the Cu and the Pb layers in the structure with δ=1.67 was found to be longer than that with δ=0.
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Takanao Asahi, Katsuhiko Hasebe, Kazuo Gesi
1991 年 60 巻 3 号 p.
921-926
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
The structures of the normal phase (I) and the monoclinic phase (II) were determined by single crystal diffractometry; at 23°C in phase I and at 1.5, −10, −40 and −70°C in phase II. In phase I HgCl
4 ion and two kinds of N(CH
3)
4 ions were determined to be in disorder from the significance test. In phase II the positional and thermal parameters as well as the occupation probabilities of ions were determined. Rotational and translational modes of HgCl
4 and the translational mode of one kind of N(CH
3)
4, TMA1, couple with the ordering in this structural phase transition. The structure is characterized by two kinds of chains composed of HgCl
4 and TMA1; one is along [001] and the other is along [100].
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Yousuke Watanabe, Takahiko Sasaki, Hideki Sato, Naoki Toyota
1991 年 60 巻 3 号 p.
927-930
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
For the title compound of a superconducting organic salt, we have observed twinning and found the twin plane to be (\bar3, 0, 7) by X-ray diffraction method at room temperature. The reduction of the diffuse intensities in the twinned crystal leads that the twin plays a role to decrease the internal strain and also acts as a cleavage plane. It is roughly estimated by the Bijvoet measurement that the twinned region takes a mirror image to the matrix.
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Jun Takeuchi, Akira Hikata, Mark J. Mckenna, Carles Elbaum, Takashi It ...
1991 年 60 巻 3 号 p.
931-937
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Ultrasonic attenuation and sound velocity have been measured for a Gd
75Y
17.5Sc
7.5 single crystal alloy under magnetic fields. Attenuation peak and velocity drop at
Tc=215 K display a large difference in magnitude when taken on cooling and on warming. The results are interpreted by means of an antiphase domain ferrimagnetic structure. A novel attenuation peak and velocity anomaly appear in a Ferro I phase between
Tc1=188 K and
Tc. The mechanisms of these features and magnetic phase diagrams deduced from these measurements are discussed.
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Kunihito Nagayama
1991 年 60 巻 3 号 p.
938-941
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Equation for the state surface for solids in terms of the specific internal energy, entropy and specific volume has been discussed in detail starting from the Grüneisen assumption. It has been revealed that the Grüneisen assumption leads us to the specific heat at constant volume to be the function of entropy only. Riemann integral written in the generalized form independent of the assumption on the Grüneisen γ has been obtained, and the strategy to reach the solution of the Riemann problem has been shown.
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P. E. A. Turchi, A. Finel
1991 年 60 巻 3 号 p.
942-946
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
New ordered states based on the A15 crystalline structure at the compositions A
5B
3 and A
7B are found from a ground state analysis of the Ising model on this lattice with first, second and weak third and seventh neighbor pair interactions. Stability properties as a function of temperature and concentration were investigated by means of a variational method. A typical prototype A15-based order disorder phase diagram is presented and discussed in relation with the experimental situation.
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Shozo Takeno, Kazunari Hori
1991 年 60 巻 3 号 p.
947-959
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
A pure one-dimensional lattice with cubic and quartic anharmonicity is studied to show the existence of two types of self-localized modes, one is stationary and the other mobile. For the former, the lattice Green’s function method is employed to formulate the frequency and a profile function of a fundamental mode and those of higher harmonics. An
s-like symmetry mode and a
p-like one are shown to be physically interesting. In the one-localized-mode problem, approximate analytical expressions for these quantities are obtained in the extreme localization. The cubic anharmonicity is shown to introduce a tiny kink-like distortion attached to the localized mode. For a propagating localized mode, numerical and approximate analytical calculations are done to show the existence of a well-defined
p-like mode.
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Yoshimi Tsuchiya
1991 年 60 巻 3 号 p.
960-967
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Sound velocity,
vs, has been measured to examine the thermodynamics of structural transitions in the liquid Se–Te system. The isothermal compressibility, κ
T, deduced from
vs together with the thermal expansion coefficient, α
P, the constant pressure specific heat,
CP, and the density shows a broad maximum when plotted as a function of temperature or concentration. It has been shown that κ
T is significantly enhanced by the structural change. Evidence has been presented that the Ehrenfest’s relations are satisfied among the excess parts of κ
T, α
P and
CP associated with the structural change.
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Fujio Kakinuma, Kenji Suzuki
1991 年 60 巻 3 号 p.
968-974
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
The heat capacities for liquid Sb–Se alloys exhibit anomalous behaviour with the change of temperature and composition. Liquid Sb
0.5Se
0.5 alloy shows maximum in the temperature dependence of heat capacity. The temperature at the maximum of heat capacity for liquid Sb
0.5Se
0.5 alloy corresponds to the temperature at which the nonmetal-metal transition occurs. The paramagnetic susceptibilities of liquid Sb
1−xSe
x alloys with 0.6≤
x≤1.0 can be attributed to the formation of dangling bonds caused by the bond breaking due to the thermal agitation. The characteristic behaviour of heat capacities for liquid Sb–Se alloys can be related to change in intermediate-range order and in local bonding configuration.
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Shigeru Takayanagi, Nobuo Wada, Yoshichika \={O}nuki, Takemi Komatsuba ...
1991 年 60 巻 3 号 p.
975-981
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
For NdCu
6 with successive four antiferromagnetic transitions below the Nèel temperature of
TN=6.10 K, high resolution measurements of the specific heat and
ac magnetic susceptibility were performed synchronously in magnetic fields up to 4 T applied along the three crystallographic axes of the orthrohmbic structure. Phase diagrams of NdCu
6 were derived from the results of field dependences of the four magnetic phases corresponding to the four specific heat peaks. The three of the phases disappear at 0.5 T applied along the
c-axis, but for the
a-axis these almost remain. We have revealed an unusual feature of the phase diagram in which the three phase lines connect with the spin flop-line for magnetic fields applied along the
b-axis. We also discussed the expected magnetic structure of NdCu
6 with respect to the results of the magnetic susceptibility measurements.
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Takahisa Yamamoto, Hideaki Kasai, Ayao Okiji
1991 年 60 巻 3 号 p.
982-986
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
It has been observed that the catalytic CO oxidation on Pd(110) exhibits kinetic oscillations shown by measurements of the reaction rate and of the work function change under certain conditions. In order to describe these phenomena, we write down a set of coupled phenomenological differential equations. The numerical results agree with experimental observations qualitatively.
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Hiroshi Yamagami, Akira Hasegawa
1991 年 60 巻 3 号 p.
987-996
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Based on the itinerant-electron model for the 5f electrons, the energy band structure and the Fermi surface are calculated for the cubic uranium dodecaboride UB
12, known to be a paramagnet having the electronic specific heat constant of 20 mJ/K
2 mole, by a self-consistent relativistic APW method with the exchange and correlation potential in the local-density approximation. The energy band structure is that of a compensated metal having 0.32 holes/cell and the compensating number of electrons. Both the hole and the electron sheets of the Fermi surface are multiply-connected with open orbits, the direction of which is consistent with the high-field magnetoresistance. By these Fermi surfaces, both the magnitude and the angular dependence of the frequency branches of the de Haas-van Alphen effect observed recently by \barOnuki
et al. can be explained reasonably well.
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Kaoru Okaniwa, Hiroshi Okamoto, Tadaoki Mitani, Koshiro Toriumi, Masah ...
1991 年 60 巻 3 号 p.
997-1004
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
IR spectroscopic measurements were made on the halogen bridged metal complexes of {M(chxn)
2Br}Br
2 (M=Pt, Pd and Ni) which have interchain N–H…Br bonds strongly coupled with the electronic state of chains. The splitting of the N–H stretching modes for Pt and Pd complexes show a good correlation with the amplitude of the CDW in the chain, i.e. with the displacement of bridging halogen ion. No splitting of the N–H band was observed for the Ni complex, which is an evidence of a transformation from a mixed valence (CDW) state to a mono-valence (the Mott-Hubbard) state by a replacement of M=Pt (or Pd) by Ni. Such IR studies were applied for the estimation of the CDW amplitude under hydrostatic pressure. The results indicated that more detailed information can be derived by the IR study than the X-ray analysis.
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Tatsuya Teshima, Naoshi Suzuki, Kazuko Motizuki
1991 年 60 巻 3 号 p.
1005-1010
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Electronic band structures are calculated for the non-magnetic states of M
1⁄3TiS
2 (M=Ti, V, Cr) and for the ferromagnetic state of Cr
1⁄3TiS
2 and Co
1⁄3TiS
2. The dispersion curves and the density of states of V
1⁄3TiS
2 and those of Cr
1⁄3TiS
2 are quite similar each other. In contrast with Co
1⁄3TiS
2 or Ni
1⁄3TiS
2 the 3
d states of Cr or V atoms hybridize mainly with the Ti 3
d states, and hybridization with the S 3
p states is small. The magnetic moment of ferromagnetic Cr
1⁄3TiS
2 is obtained to be 2.9 μ
B per Cr ion, which is about four times larger than the observed value. The moment of ferromagnetic Co
1⁄3TiS
2 is obtained to be 0.79 μ
B per Co ion, which is close to the experimental value, 0.5 μ
B. The calculated densities of states at the Fermi level explain well the observed M-dependence of the coefficient γ of electronic specific heat.
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Hiroshi Yamagami, Akira Hasegawa
1991 年 60 巻 3 号 p.
1011-1021
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
Based on the itinerant-electron model for the 4f electrons, the energy band structure and the Fermi surface is calculated for the mixed-valence cerium compound CeNi and its reference material LaNi by a self-consistent relativistic APW method with the exchange and correlation potential in the local-density approximation. Both CeNi and LaNi are compensated metals, and their hole and electron Fermi surfaces are multiply-connected sheets with open orbits, the direction of which is consistent with the high-field magnetoresistance. Though they are quite different from each other, the Fermi surfaces for CeNi and LaNi can explain reasonably well both the magnitude and the angle dependence of the de Haas-van Alphen effect frequency branches. These theoretical results suggest that the 4f electrons may be itinerant in the ground state in CeNi, as they are in CeSn
3.
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Yoshichika \={O}nuki, Izuru Umehara, Nobuyuki Nagai, Yoshiko Kurosawa, ...
1991 年 60 巻 3 号 p.
1022-1027
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
We have measured the de Haas-van Alphen effect of the antiferromagnetic substance NdCu
6. The Fermi surface of NdCu
6 is found to be similar to the one of the non-
f reference material of LaCu
6. The cyclotron masses are light, ranging from 0.077
m0 to 1.31
m0.
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Tsuyoshi Yamaguchi, Nobuhisa Fujima
1991 年 60 巻 3 号 p.
1028-1039
発行日: 1991/03/15
公開日: 2007/05/29
ジャーナル
認証あり
Electronic states of steps on the Si(001) surface are calculated by the DV–Xα method. The calculated steps are the unreconstructed S
b, reconstructed S
b, unreconstructed S
a, buckled S
a, and dimer-chain S
a steps. The dangling bonds near the steps interact with each other. The dangling-bond levels appear in the middle of the band gap. The charge distribution of dangling-bond levels of the dimer on the upper terrace of the unreconstructed S
a step is slightly asymmetric, although the dimer is symmetric. The charge distribution of the buckled S
a step where the dimer is tilted by 10 degrees is buckled, but its shape does not reproduce the STM image. A new model of the S
a step is proposed. The atomic structure of step edge of the higher terrace is a zig-zag chain of dimers. The charge distribution of the dimer-chain S
a step well reproduces the large buckling of the STM image.
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Kozo Okada, Yasuhiro Seino, Akio Kotani
1991 年 60 巻 3 号 p.
1040-1050
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
The role of the Cu 4
s conduction band in the Cu 2
p-XPS (X-ray photoemission spectrum) of Nd
2−xCe
xCuO
4 is investigated on the basis of both a simple CuO
4 cluster model and the impurity Anderson model. The impurity Anderson model consists of the impurity Cu 3
d shell and the valence and conduction bands which are obtained from the O 2
p and Cu 4
s bands by the tight-binding approximation. From the carrier concentration dependence of the Cu 2
p-XPS, the electron doping mechanism is discussed. If the Cu 4
s level is lower in energy than that estimated from the energy band calculation by a few eV, the doped electrons are shown to occupy the Cu 4
s band in the low-doping regime.
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Ryusuke Ikeda, Tetsuo Ohmi, Toshihiko Tsuneto
1991 年 60 巻 3 号 p.
1051-1069
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
We further develop the theory of renormalized superconducting fluctuations in a strong field, taking account of layer structure in high temperature superconductors and renormalization of fluctuations of higher Landau levels, both of which we neglected in our previous works. Performing detailed comparisons with recent resistivity data for bulk single crystal samples of YBCO and BSCCO, we find that the resulting expressions of fluctuation conductivities quantitatively explain the broadening of resistive transition for both cases of the field perpendicular and parallel to current. In particular, the single expression for the case
I⊥
B can cover not only the broad transition region but also the flux flow region observed at lower temperature.
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Kenji Takanaka
1991 年 60 巻 3 号 p.
1070-1077
発行日: 1991/03/15
公開日: 2007/06/01
ジャーナル
認証あり
We numerically calculate the transition temperature and the upper critical fields for superconducting superlattices with spatial variations of the BCS interaction, the density of states and the diffusion constant. For the superlattices composed of thin layers, the Debye cutoff frequency plays a role to make the states with large eigenvalues less important. By virtue of this, a simple expression for the perpendicular upper critical field
Hc2⊥ is obtained, if the diffusion constants are same in both thin layers.
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