bluuebunny/crossref_metadata_2025 huggingface dataset:
The Ameliorating Effects of Cognition-enhancing Chinese Herbs on Scopolamine-and MK-801-induced Amnesia in Rats
Authors: Lin Ying-Chih , Wu Chi-Rei , Lin Chun-Ju , Hsieh Ming-Tsuen
Published: October 2003

The study was to investigate the ameliorating effects of three Chinese herbs — Achyranthes bidentata (AB), Ophiopogon japonicus (OJ) and Cnidium monnieri (CM) on scopolamine (SCOP)- and MK-801-induced amnesia by using a passive avoidance task in rats. AB, OJ and CM at 0.1 and 0.3 g/kg prolonged the step-through latency (STL) of the retention trial. In addition, AB, OJ and CM reversed the STL shortened by MK-801, but only AB reversed the STL shortened by SCOP. In conclusion, these Chinese herbs possess cognition-enhancing activities and anti-amnestic effects, but the mechanism of the effect of AB was different from those of OJ and CM.
A Study on the Central Neural Pathway of the Heart, Nei-Kuan (EH-6) and Shen-Men (He-7) with Neural Tracer in Rats
Authors: Jang Insoo , Cho Kiho , Moon Sangkwan , Ko Changnam , Lee Bonghee , Ko Byungmoon , Lee Changhyun
Published: October 2003

The purpose of this morphological study was to investigate the relations between meridians, acupoints and viscera using neuroanatomical tracers. The labeled areas of the spinal ganglia, sympathetic chain ganglia, spinal cord and the brain projecting to the heart, Nei-Kuan (EH-6) and Shen-Men (He-7) were observed following injection of WGA-HRP and pseudorabies virus (PRV). The results were as follows. Overlapping bilaterally labeled ganglion areas after heart, Nei-Kuan (EH-6) or Shen-Men (He-7) injection of WGA-HRP were found in middle cervical, stellate and T4 sympathetic and T2-T6 spinal ganglia. In brain, labeled neurons from all three sites were found in the A1 noradrenalin cell group/C1 adrenalin cell group/caudoventrolateral reticular n., n. tractus solitarius, n. ambiguus, rostroventrolateral n., C3 adrenaline cell group, raphe obscurus n., raphe pallidus n., raphe magnus n., lateral paragigantocellular reticular n., locus coeruleus, subcoeruleus n., Kolliker-Fuse n., A5 cell group, central gray matter, paraventricular hypothalamic n. and arcuate hypothalamic n.. In conclusion, these morphological results suggest that the interrelationship of acupoints (Nei-Kuan and Shen-Men) and viscera (heart) may be related to the central autonomic centers of the spinal cord and brain.
Effect of Sairei-To Combined with Aspirin and Prednisolone on Four Recurrent Reproductive Failure Women who are Positive for Anti-Phospholipid Antibodies
Authors: Takakuwa Koichi , Ishii Keisuke , Takaki Yoshihiro , Natsume Norihiro , Adachi Hiroshi , Kurata Hitoshi , Tamura Masaki , Kurabayasi Takumi , Tanaka Kenichi
Published: October 2003

We treated four pregnancy cases positive for antiphospholipid antibodies (APLs) who had experienced recurrent second trimester fetal or neonatal losses using a Japanese modified Chinese herbal medicine, Sairei-to, low dose aspirin and adrenocorticosteroid hormone. The clinical courses of their new pregnancies in conjunction with the dynamic changes in their APL titers are described in this paper, and the possible efficacy of this treatment is discussed.

The concept that autoimmune abnormalities, especially positive APLs, are generative factors for a range of reproductive failures, such as recurrent abortions, intrauterine growth retardation, intrauterine fetal death and preeclampsia, is now attracting a great deal of attention in the fields of reproductive immunology and perinatal medicine (Yasuda et al., 1995). The main mechanisms in the generation of reproductive failures are considered to be direct damage to chorionic villi by APLs during the period of placentation (Rote et al., 1998), as well as the formation of thrombi intervillous spaces (Arakawa et al., 1999). Considering these mechanisms of the reproductive failure generation by APLs, the application of immune suppressive therapy in combination with anti-coagulation therapy should be reconsidered as a treatment option.

In this context, we treated four pregnancy cases positive for APLs who had experienced recurrent second trimester fetal or neonatal losses using a Japanese modified Chinese herbal medicine, Sairei-to, low dose aspirin and an adrenocorticosteroid hormone.
Are Four Neutrino Models Ruled Out?
Authors: Foot R.
Published: October 2003

We show explicitly that four neutrino models of the 2+2 variety still provide an acceptable global fit to the solar, atmospheric and LSND neutrino data. The goodness of fit, defined in the usual way, is found to be 0.26 for the simplest such model. That is, we find that there is a 26% probability of obtaining a worse global fit to the neutrino data. We also make some specific comments on the paper, "Ruling out four-neutrino oscillation interpretations of the LSND anomaly", hep-ph/0207157, and explain why they reached drastically different conclusions.
Gravitomagnetic Time Delay and the Lense–Thirring Effect in Brans–Dicke Theory of Gravity
Authors: Barros A. , Romero C.
Published: October 2003

We discuss the gravitomagnetic time delay and the Lense–Thirring effect in the context of Brans–Dicke theory of gravity. We compare the theoretical results obtained with those predicted by general relativity. We show that within the accuracy of experiments designed to measure these effects both theories predict essentially the same results.
Recent Measurements of CP-Violation at the B-Factories
Authors: Sciolla Gabriella
Published: October 2003

Recent measurements of time-dependent CP-asymmetries at the B-factories have led to substantial progress in our understanding of CP-violation. In this paper, we review some of these experimental results and discuss their implications in the Standard Model and their sensitivity to New Physics.
Detecting Topology in a Nearly Flat Hyperbolic Universe
Authors: Weeks Jeffrey R.
Published: October 2003

Cosmic microwave background data shows the observable universe to be nearly flat, but leaves open the question of whether it is simply or multiply connected. Several authors have investigated whether the topology of a multiconnected hyperbolic universe would be detectable when 0.9<Ω<1. However, the possibility of detecting a given topology varies depending on the location of the observer within the space. Recent studies have assumed the observer sits at a favorable location. The present paper extends that work to consider observers at all points in the space, and (for given values of Ωm and ΩΛ and a given topology) computes the probability that a randomly placed observer could detect the topology. The computations show that when Ω=0.98 a randomly placed observer has a reasonable chance (~50%) of detecting a hyperbolic topology, but when Ω=0.99 the chances are low (<10%) and decrease still further as Ω approaches one.
Brane Gases on K3 and Calabi–Yau Manifolds
Authors: Easson Damien A.
Published: October 2003

We initiate the study of Brane Gas Cosmology (BGC) on manifolds with nontrivial holonomy. Such compactifications are required within the context of superstring theory in order to make connections with realistic particle physics. We study the dynamics of brane gases constructed from various string theories on background spaces having a K3 submanifold. The K3 compactifications provide a stepping stone for generalizing the model to the case of a full Calabi–Yau threefold. Duality symmetries are discussed within a cosmological context. Using a duality, we arrive at an N=2 theory in four dimensions compactified on a Calabi–Yau manifold with SU(3) holonomy. We argue that the Brane Gas model compactified on such spaces maintains the successes of the trivial toroidal compactification while greatly enhancing its connection to particle physics. The initial state of the universe is taken to be a small, hot and dense gas of p-branes near thermal equilibrium. The universe has no initial singularity and the dynamics of string winding modes allow three spatial dimensions to grow large, providing a possible solution to the dimensionality problem of string theory.
Interjet Energy Flow/Event Shape Correlations
Authors: Berger Carola F. , Kúcs Tibor , Sterman George
Published: October 2003

We identify a class of perturbatively computable measures of interjet energy flow, which can be associated with well-defined color flow at short distances. As an illustration, we calculate correlations between event shapes and the flow of energy, QΩ, into an interjet angular region, Ω, in high-energy two-jet e+e--annihilation events. Laplace transforms with respect to the event shapes suppress states with radiation at intermediate energy scales, so that we may compute systematically logarithms of interjet energy flow. This method provides a set of predictions on energy radiated between jets, as a function of event shape and of the choice of the region Ω in which the energy is measured. Non-global logarithms appear as corrections. We apply our method to a continuous class of event shapes.
Macroscopic Quantum Effect Based on No-Field Quantum Hall Effect Found in Electric Properties of Low-Doped c-Oriented LaSrCuO Film Crystal
Authors: Sugahara M. , Kaneda H. , Fukutomi M. , Asai J. , Wada M. , Hasegawa H. , Bogolubov N. N.
Published: October 2003

We study the film-thickness dependence of ||c dielectric polarization of La 1.95 Sr 0.05 CuO 4 thin film crystal, and find the existence of special film thicknesses where the polarization reveals a large amplitude alternate change with sign change. At the special thicknesses, we find interference patterns in the polarization-charge dependence of the film capacitance. With the use of small area device, we observe in the film the quantum resonance between the current-induced oscillation and coherent electromagnetic wave of microwaves (10 GHz), the CO 2 laser (10.6 μm), and the He–Ne laser (3.39 μm). A theoretical study based on the no-field quantum Hall effect is made to explicate these effects.
A Modification of the Projection Operator Method for Resonances
Authors: Khan Sohail A.
Published: October 2003

The Projection Operator Method as applied to the study of resonances is first briefly reviewed. Its shortcomings, in the context of reactions that involve forbidden states are mentioned. The forbidden states arise due to the requirement of antisymmetrization imposed by the Pauli exclusion principle, on the many body wave function. A modification that takes into account the forbidden states is suggested. The modified formalism is applied to the alpha-alpha scattering involving realistic interactions. In place of the usual practice of using oscillator wave functions, bound states are extracted from the scattering potential and are used in obtaining the results. The calculated resonance energies, widths and phase shifts, show excellent agreement with experiment. Since forbidden states should be present in almost any nucleus-nucleus interaction the procedure has a wide range of applicability. It is concluded that the modifications are necessary, if agreement with experiment is to be established.
EPR of VO2+, Cu2+ and Mn2+ Ions Doped in LiHSO4 Single Crystals
Authors: Ikram M. , Singh R. J.
Published: October 2003

The EPR spectra of VO 2+, Cu 2+ and Mn 2+ ions doped in LiHSO 4 single crystals are reported. The foreign impurities appear to displace Li + ions, which are situated in voids formed by the hexagonal closest packing of bigger sulphate ions in the crystal structure. VO 2+ and Mn 2+ show characteristic hyperfine structure but no hyperfine splitting was observed in the spectra of Cu 2+ ions. It appears that VO 2+ and Mn 2+ are situated in one kind of void situated in an ordered way. The Cu 2+ ions may be occupying both kinds of voids, distributed in an irregular fashion. The molecular orbital binding coefficients β2 and α2 are calculated in the case of VO 2+.
Five-Loop Critical Temperature Shift in Weakly Interacting Homogeneous Bose–Einstein Condensate
Authors: Kleinert H.
Published: October 2003

Using variational perturbation theory, we calculate the shift in the critical temperature Tcup to five loops to lowest order in the scattering length a and find [Formula: see text], where n is the particle density. Our result is slightly lower than the latest Monte Carlo result (1.32±0.02) an1/3.
Global-Space Propagating Characteristics of Pulsed-Laser-Induced Shock Waves
Authors: Li Zhihua , Zhang Duanming , Yu Boming , Guan Li
Published: October 2003

Under the propagating limitation-conditions and based on the pulsed-laser-induced plasma shock wave theory,1the propagating rules in the global free space (including close areas and mid-far areas) of pulsed-laser-induced shock waves are established for the first time. Compared with the previous work by Bian et al.,2our theoretical model can directly lead to the relationship of the initial Mach number M0of plasma shock waves and the whole energy E released into plasma shock waves from a pulsed laser without any approximations or any unnecessary experimental parameters. Here, M0is also related to the pulse duration τ0and the sound velocity υ0in the atmosphere; the variation of attenuation index τ, as a function of laser parameters (especial τ0), is also obtained, and our theoretical predictions of mid-far propagating rules of plasma shock waves are in good agreement with experimental results. In addition, it should be noted that Sedov–Taylor solutions to the ideal shock wave in a point explosion are only the approximations of the propagating rules in the mid-far area of pulsed-laser plasma shock waves that we obtained.
Resummation Methods for Analyzing Time Series
Authors: Gluzman S. , Yukalov V. I.
Published: October 2003

An approach is suggested for analyzing time series by means of resummation techniques of theoretical physics. A particular form of such an analysis, based on the algebraic self-similar renormalization, is developed and illustrated by several examples from the stock market time series.
Renormalization Group Analysis of October Market Crashes
Authors: Gluzman S. , Yukalov V. I.
Published: October 2003

The self-similar analysis of time series, suggested earlier by the authors, is applied to the description of market crises. The main attention is payed to the October 1929, 1987 and 1997 stock market crises, which can be successfully treated by the suggested approach. The analogy between market crashes and critical phenomena is emphasized.
Reduction in Difference of the Resistive and Magnetic Critical Temperature in Irradiated (Bi,Pb)-2223 Superconductors
Authors: Ghosh A. K. , Basu A. N.
Published: October 2003

The resistive and magnetic critical temperatures of α-irradiated (Bi,Pb)-2223 superconductors are measured from resistivity and the real part of the ac susceptibility. Difference in these two critical temperatures are found to be decreased with irradiation monotonically. Change in difference of these two temperatures with irradiation are discussed in this paper.
AFM Observation and Application of Diamond-Like Carbon Films
Authors: Chi Ning , Qingrun Hou , Gao J.
Published: October 2003

The surface morphologies of pulsed laser deposited thick diamond-like carbon films were studied by optical microscopy and atomic force microscopy. The thick films had a much larger density of particulates and a much rougher surface than thin films. As a protective coating, a thin film was deposited on porous silicon. Two peaks (708 nm and 768 nm) were suppressed greatly while the peak 646 nm was not. The reason for these changes was discussed.
Study of Spin Polarons in Extended t–J Model by Self-Consistent Born Approximation
Authors: Yang Jun , Yin Wei-Guo , Gong Chang-De
Published: October 2003

By introducing the second and third neighbors t′ and t″ terms to the pure t–J Hamiltonian, we could obtain the quasiparticle dispersion data which are consistent with the experimental results for Sr 2 CuO 2 Cl 2. The correlation of hole motion with ferromagnetic correlations is automatically included in our approach, thus leading to a experimentally observed asymmetry of the quasiparticle between k and k + (π, π).
c-Axis Resistivity Due to Transport of Fermionic Pairs in the Cuprates
Authors: Sardar Manas
Published: October 2003

With the assumption of complete incoherence of single electron transport along the c-axis, it is argued that it takes place by coherent hopping of singlet pairs that are fermionic in character. This will lead to a correction to the 1/Tc-axis resistivity calculated by Anderson et al.6 The c-axis resistivity coming from this extra channel of transport is shown to have the same temperature dependence as the inplane resistivity (linear in T) and mildly sensitive to the inplane carrier concentration through the modification of the density of states at the fermi surface. It is argued that the resistivity due to transport in this extra channel will be very sensitive to the c-axis disorder and show an upturn at low temperatures due to c-axis disorder and scattering by acoustic phonons.
A Toy Model for Understanding the Conceptual Framework of Protein Folding: Rubik's Magic Snake Model
Authors: Iguchi Kazumoto
Published: October 2003

A toy model is introduced in order to understand the conceptual framework of the protein folding problem.
p-Wave Pairing and Colossal Magnetoresistance in Manganese Oxides
Authors: Kim Yong-Jihn
Published: October 2003

We point out that the existing experimental data of most manganese oxides show the frustratedp-wave superconducting condensation in the ferromagnetic phase in the sense that the superconducting coherence is not long enough to cover the whole system. The superconducting state is similar to the A1 state in superfluid He-3. The sharp drop of resistivity, the steep jump of specific heat, and the gap opening in tunneling are well understood in terms of the p-wave pairing. In addition, colossal magnetoresistance (CMR) is naturally explained by the superconducting fluctuations with increasing magnetic fields. The finite resistivity may be due to some magnetic inhomogeneities. This study leads to the possibility of room temperature superconductivity.
Conditions for a Solitonic Solution of the Doener–Goldin Equation of Quantum Mechanics
Authors: Caparelli E. C. , Mizrahi S. S. , Dodonov V. V.
Published: October 2003

A solitonic solution to the free-particle motion of Doebner–Goldin nonlinear equation is shown to exist under special conditions. For small values of the nonlinearity parameters, the solution is a plane wave modulated by a cos function, and the solitonic one arises when the parameters surpass some critical values. The mean energy of the particle is a conserved quantity and the continuity equation holds. We also verify that there is no nonlinear gauge transformation (in the sense of Ref. 12) that linearizes that equation.
Static and Dynamic Behavior of Ferronematics Under Magnetic Fields
Authors: Motoc Cornelia , Petrescu Emil
Published: October 2003

The static and dynamic behavior under magnetic elds of ferronematics obtained by adding an organomagnetic material to the nematic E3 is investigated. First, by using both optical and electrical measurements, an increase of the threshold field for magnetic Freedericksz transition was noticed. Second, we examined both theoretically and experimentally the relaxation phenomena occurring in these ferronematics when the magnetic field was suddenly varied. We found that for ferronematics the relaxation processes are delayed when compared to those occurring in pure nematics. The threshold fields for magnetic Freedericksz transition were determined by means of the relaxation time and the results are in good agreement with the ones obtained when using the optical and electrical methods reported before.
Joint Density of States of Wide-Band-Gap Materials by Electron Energy Loss Spectroscopy
Authors: Fan X. D. , Peng J. L. , Bursill L. A.
Published: October 2003

Kramers–Kronig analysis for parallel electron energy loss spectroscopy (PEELS) data is developed as a software package. When used with a JEOL 4000EX high-resolution transmission electron microscope (HRTEM) operating at 100 keV this allows us to obtain the dielectric function of relatively wide band gap materials with an energy resolution of approx. 1.4 eV. The imaginary part of the dielectric function allows the magnitude of the band gap to be determined as well as the joint-density-of-states function. Routines for obtaining three variations of the joint-density of states function, which may be used to predict the optical and dielectric response for angle-resolved or angle-integration scattering geometries are also described. Applications are presented for diamond, aluminum nitride (AlN), quartz ( SiO 2) and sapphire ( Al 2 O 3). The results are compared with values of the band gap and density of states results for these materials obtained with other techniques.
Some Exact Results of Hubbard Model at Finite Temperature
Authors: Feng Sze-Shiang
Published: October 2003

Two theorems of the Hubbard model at nite temperature are proven employing the fluctuation–dissipation theorem and particle–hole transform. The main conclusion states that for the prototype Hubbard model, the expectation value of [Formula: see text] will be of order Nλ at any temperature except those critical.
Nucleation Model for the Description of Glass Formation
Authors: Micoulaut M.
Published: October 2003

We present in this letter a model of glass formation using energy barriers and a crystal nucleation process. We then analyze the corresponding dynamical equation in the vicinity of the stationary solutions. The occurence of a pure amorphous solution (i.e. glass) is due to the contribution of a ratio depending on the cooling rate and the crystal nucleation frequency. We also construct time-temperature transformation (TTT) curves in order to relate the model with the kinetic treatment of glass formation.
The Caldirola–Kanai Theory from "Brownian" Path Integral Quantum Mechanics
Authors: Botelho Luiz C. L. , da Silva Edson P.
Published: October 2003

We deduce the classsical one-dimensional Caldirola–Kanai action from quantum mechanics, at the WKB limit, formulated as an electronic flux interacting with an environment in the Langevin–Brownian phenomenological path integral framework.
Booms and Crashes in Self-Similar Markets
Authors: Gluzman S. , Yukalov V. I.
Published: October 2003

Sharp changes in time series representing market dynamics are studied by means of the self-similar analysis suggested earlier by the authors. These sharp changes are market booms and crashes. Such crises phenomena in markets are analogous to critical phenomena in physics. A simple classi cation of the market crisis phenomena is given.
Pressure Dependence of Superconducting Transition Temperature Tc in a Series of Zn-Substituted YBa2Cu3-xZnxO7-δ Single Crystals: Effects of Pairing-Related Dynamic Processes Versus Static Lattice Modifications
Authors: Li Xiaohang , Lu L. , Li Shanlin , Jing X. N. , Dian-Lin Zhang , Wang Z. Z.
Published: October 2003

The pressure dependence of superconducting transition temperature Tc was investigated on single-crystal samples of Zn-substituted YBa 2 Cu 3-x Zn x O 7-δ. In contrast to previous measurements on polycrystalline samples where, because of the broad transition, large uncertainty exists in determining the detailed pressure dependence of Tc, our measurements revealed that adding Zn impurities only slightly enhances the dTc=dP (where P denotes the pressure). The absolute value of dT c =dP is small in the whole range of x investigated, despite of the dramatic depression of Tc upon the substitution. The results seem to demonstrate that the depression of T c , and hence the dynamic processes responsible for the pairing mechanism, are quite irrelevant to, or insensitive to the pressure-induced static lattice modifications.
Submicrometer Shadow Mask Fabricated by Anisotropic Wet Etching and Focused Ion Beam Techniques for Nanofabrication in UHV
Authors: Sheng Hanyu , Fujita Daisuke , Ohgi Taizo , Okamoto Hiroshi , Nejoh Hitoshi
Published: October 2003

We have developed a new method for fabricating a silicon submicrometer shadow mask for nanofabrication in ultra-high vacuum. Combining KOH anisotropic wet etching, electron beam lithography, reactive ion etching and focused ion beam techniques, a pattern size of 2.5×2.5 mm2 and opaque part about 1 μm can be obtained.
Generalization of Tomonaga–Luttinger Liquids and the Calogero–Sutherland Model: Microscopic Models for the Haldane Liquids
Authors: Iguchi Kazumoto
Published: October 2003

We discuss the quantum many-body system interacting with a separately symmetric two-body potential in higher dimensions as a generalization of the Calogero–Sutherland model in one dimension. This system exhibits the properties of a Haldane liquid such as Haldane–Wu (i.e., fractional exclusion) statistics, broken particle–hole symmetry and the existence of pseudo-Fermi surface as a generalization of the cencept of Tomonaga–Luttinger liquids in one dimension.
Instability of One-Dimensional Lennard–Jones System — Particle Density Dependence
Authors: Okabe Tsuneyasu , Yamada Hiroaki
Published: October 2003

We report dynamical instability of one-dimensional system with the nearest-neighbor Lennard–Jones interaction. A presence of new certain region between weakly and strongly chaotic region has been found in energy dependence of the maximal Lyapunov exponent. It is numerically shown that the presence of the region is enhanced by decrease of the particle density. The characteristics of the Lennard–Jones system, which are different from the FPU and soft-core system, are explained by means of a local instability of the potential surface. In addition, the relation between the presence of the new region and spatio-temporal pattern is also discussed in the low density cases.
Squeezing Properties in Mesoscopic Josephson Junction with Nonclassical Radiation Field
Authors: Bin Shao , Jian Zou , Qian-Shu Li
Published: October 2003

We consider a system of mesoscopic Josephson junction interacting with nonclassical radiation field and investigate any order squeezing for the mesoscopic Josephson junction subsystem. Our results show that if the field is initially prepared in a squeezed vacuum and the junction is in its lowest energy state (the vacuum state), then as the time evolves the Josephson junction subsystem can exhibit any order squeezing.
On a Possibility to Measure Thermo-Electric Power in SNS Structures
Authors: Ahmedov B. J.
Published: October 2003

Two dissimilar Josephson junctions, which are connected to a heater can act as precise batteries. Because of the di erencein thermoelectric power of these batteries, circuit with two dissimilar batteries, under heat flow ΔT~10-5 K would have a net EMF 10-11 V around the zero-resistance loop leading to a loop's time-varying magnetic flux. It is shown that its theoretical value is proportional to both the temperature difference as well as the disparity in the thermoelectric powers of the two junctions.
Static Local Field Factor for Dielectric Screening Function of Electron Gas at Metallic and Lower Densities
Authors: Sarkar A. , Sen D. , Haldar S. , Roy D.
Published: October 2003

A simple parametric form for the static local field factor G(q) which appears in the dielectric screening theory of an electron gas is proposed. A very accurate fit of Ceperley–Alder data of electron correlation energy in the entire density range using Levin–Weniger interpolant is obtained and used for the calculation of G(q). Both the short- and long- wavelength limits of G(q) are satis ed exactly in the present formulation which ensures fulfilment of a number of other legitimate criteria and produces some interesting results. A comparative study of the various static local eld factors derived so far vis-a-vis the present work is made. Even within the approximations of a static self-consistent theory, reasonable prediction regarding Wigner Crystallization is obtained in the present work.
Note on the Role of Dimensionality in the Stability of a Confined Condensed Bose Gas: Reply to a Comment
Authors: Salasnich Luca
Published: October 2003

In this letter we reply to a comment of Brosens, Devreese and Lemmens (quant-ph/9712046) on our paper (Mod. Phys. Lett.B11, 1249 (1997)) that analyzes the role of dimensionality in the stability of a confined condensed Bose gas. We generalize our previous results and discuss the e ect of a short range attractive interaction between the bosons.
Nonmagnetic Phase of a Dilute Transition Series Alloy
Authors: Mattis Daniel C.
Published: October 2003

We construct a nonmagnetic singlet ground state and the magnetic excited states of an isolated S=1/2 impurity atom in a metal, using holes below the Fermi level and electrons above it. The error in the variational energies is O(1%). The size of magnetic eigenstates is very large where the energy is a minimum, while the nonmagnetic ground is always compact with ξ=O(1) inter-atomic distance. This relates to the disappearance or re-appearance of magnetic moments and their RKKY-type interactions with slight shifts in the Fermi level.
A Kondo Impurity in One-Dimensional Correlated Conduction Electrons
Authors: Wang Xiaoqun
Published: October 2003

A spin-1/2 magnetic impurity coupled to a one-dimensional correlated electron system have been studied by applying the density renormalization group method. The Kondo temperature is substantially enhanced by strong repulsive interactions in the chain, but it changes non-monotonically in the case of electron attraction. The magnetization of the impurity at zero-temperature shows local Fermi liquid behavior.
Spin-Liquid State for Two-Dimensional Heisenberg Antiferromagnets on a Triangular Lattice
Authors: Dong Zhan-Hai , Feng Shiping
Published: October 2003

The spin liquid state of the antiferromagnetic Heisenberg model on a triangular lattice is studied within the self-consistent Green's function method. It is shown that the spin excitation spectra is gapless, and ground-state energy per site is Eg/NJ=-0.966, which is in very good agreement with the results obtained within the variational Monte Carlo method based on the resonating-valence-bond state. Some thermodynamic properties are also discussed.
Electron Density Parameters
Authors: Wojciechowski Kazimierz F.
Published: October 2003

An analysis of the density parameters r m , of the mobile part of the electron gas in metals and r b , related to the "bonding valence" together with r B , fitted to the bulk modulus and r f , fitted to the Fermi energy is given. It is shown that the ground state properties of the simple metals may be approximately described by one parameter, while those of transition metals by two different density parameters.
Effects of Strong Coupling Magnetopolaron in Quantum Dot
Authors: Zhou Haiyang , Gu Shiwei , Shi Yaoming
Published: October 2003

With the use of variational method of Pekar type, we have calculated both the ground state energy and the excited state energy of strong coupling magnetopolaron in disk-shape quantum dot. The dependence of cyclotron resonance frequency of magnetopolaron on the magnetic eld and the confinement strength of quantum dot and quantum well is depicted. The limiting case of bulk type and strict two-dimensional type is discussed.
Macroscopic Squeezing in Bose–Einstein Condensate
Authors: Navez Patric
Published: October 2003

We study the ground state of a uniform Bose gas at zero temperature in the Hartree–Fock–Bogoliubov (HFB) approximation. We find a solution of the HFB equations which obeys the Hugenholtz–Pines theorem. This solution imposes a macroscopic squeezing to the condensed state and as a consequence displays large particle number fluctuations. Particle number conservation is restored by building the appropriate U(1) invariant ground state via the superposition of the squeezed states. The condensed particle number distribution of this new ground state is calculated as well as its fluctuations which present a normal behavior.
Interaction Hamiltonian fro Relative-Number-Phase of Ban's Phase Operator Formalism
Authors: Fan Hong-Yi , Wang Yi-Hua
Published: October 2003

Based on Ban's phase operator formalism, we introduce the interaction Hamiltonian for studying relative-number-phase uncertainty relation. The time evolutions for the relative-number and phase operators are also discussed.
Anomalous Hall Effect of YBa2Cu3O7-δ in the Low-Magnetic-Field Limit
Authors: Yun-Ping Wang , Dian-Lin Zhang , Bai-Ru Zhao
Published: October 2003

The Hall effect of YBa 2 Cu 3 O 7-δ epitaxial films in the vicinity of superconducting transition was studied under ultra low magnetic fields down to 10-3 T where some field-induced extrinsic effects, such as the reduction and broadening of the transition temperature and the enhancement of fluctuation, can be neglected. The Hall sign reversal was still observed down to the lowest field we arrived, which shows that any mechanism connected with above mentioned extrinsic changes cannot be responsible for the effect. The Hall resistivity ρxy, Hall angle tan α and Hall conductivity σxy are all simply proportional to the magnetic field, resembling the behaviors of the ordinary Hall effect in the low-magnetic-field limit. The temperature range with observable negative Hall resistivity coincides with the critical fluctuation region. These behaviors shows that the negative Hall effect cannot be understood in the picture of flux flow.
Differences Between Classical and Superconductive Percolation Fractals
Authors: Skal Asya S.
Published: October 2003

The average mass of the backbone has fractal dimensionalities [Formula: see text] for superconductive percolation and theat of classical percolation [Formula: see text] in dimensions d = 3, 4, 5 and 6 respectively. A new fractal dimension of "dead ends" [Formula: see text] refers to the difference between two percolations, because if most of the mass of the backbone belong to the dead ends, the superconductive behavior becomes impossible. The definition of the minimum path (or the chemical distance) and its fractal dimensionality does not exist in the superconductive percolation. Instead of the "red" bonds in classical percolotion, one has the real physical phenomena — the "special" nodes, which can be found in the experimental investigations. The order of ramification R for superconductive fractals is equal to the critical exponent of the number of the "special" nodes N(p) ∝ (p - pc)dν, (R = dν). The fractal dimension of order of ramification equals to zero.
Optical Conductivity in the Copper Oxide Materials
Authors: Huang Zhongbing , Feng Shiping
Published: October 2003

The frequency- and temperature-dependent optical conductivity of the copper oxide materials in the underdoped and optimal doped regimes are studied within the t–J model. The conductivity spectrum shows the unsual behavior at low energies and anomalous midinfrared peak in the low temperatures. However, this midinfrared peak is severely depressed with increasing temperatures, and vanishes at higher temperature.
Crossover Between Localization and Delocalization in a Random Non-Integer n-MER Chain
Authors: Zekri N. , Bahlouli H.
Published: October 2003

We study in the paper numerically the nature of the electronic states in a random system with impurities constituted by dimers and monomers having the same potential strength. The combination of these two impurity lengths in this system can be seen as a random impurity with a non-integer average size varying between 1 and 2 depending on the concentration of the monomers in the impurities. We found with the help of the Lyapunov exponent, a range of host lattice potentials for which a crossover between localized and delocalized states exists. This crossover is obtained for different averaged non-integer n-mer sizes and tends to a phase transition when the averaged size goes to an integer value (only dimers). These results can also be extended to higher non-integer n-mer systems.
Quantum Statistics of Composites: Ehrenfest–Oppenheimer-Bethe's Rule
Authors: Fujita Shigeji , Morabito David L.
Published: October 2003

The quantum statistics of a composite is studied by looking at its Center-of-Mass (CM), which moves, following general principles of quantum theory and relativity. With respect to the CM motion the Ehrenfest–Oppenheimer–Bethe rule is shown to hold: a composite is fermionic if it contains an odd number of elementary fermions, bosonic if the number of fermions in it is even.
Weak Localization Effect in Superconductors
Authors: Kim Yong-Jihn , Chang K. J.
Published: October 2003

We investigate the effect of weak localization on the transition temperatures of superconductors using Anderson's time-reversed scattered-state pairs, and show that disorder weakens electron–phonon interactions. With solving the BCS T c -equation, the calculated values for T c are in good agreement with experimental data for various two- and three-dimensional disordered superconductors. We find that the critical sheet resistance for the suppression of superconductivity in thin films does not satisfy the universal behavior but depends on sample, in good agreement with experiments.
Ground State Properties of Three-Dimensional Acoustic Polarons
Authors: Wang Xiaoqun
Published: October 2003

The ground state properties of a three-dimensional acoustic polaron are studied using the path integral Monte Carlo technique. In the strong coupling regime, there exists a self-trapped state, which originates from a short ranged electron–phonon interaction, and is of delocalized nature.
Electrical and Magnetic Studies on SrBi5FeTi4O18
Authors: James A. R. , Bhimasankaram T.
Published: October 2003

The compound SrBi 5 FeTi 4 O 18 is a five-layered material belonging to the family of Bismuth Layer Structured Ferroelectrics. Samples were prepared by the ceramic route and dc conductivity measurements were performed from room temperature to 550°C and the activation energies were calculated. Impedance and modulus spectroscopy were used as tools to analyse the sample's behavior as a function of frequency. Relaxations in the sample were noted. Magnetization measurements were performed from 80 K to 300 K. The results of the electrical and magnetic studies are presented.
Study of the Electric Relaxation Phenomena in Nematic Liquid Crystals
Authors: Mitroi Razvan , Iancu Vladimir
Published: October 2003

The electric relaxation phenomena in nematic liquid crystals are studied using Fröhlich distribution. Different models are proposed for the relaxation of the conduction and polarization currents respectively. A statistical fitting procedure is applied to the obtained experimental data. The parameters of the relation time distribution are computed. The results are showing a very good agreement between the experimental data and the proposed models.
A Combined Mechanism Mediated by Lochons and Phonons for Cuprate Superconductors
Authors: Sinha K. P.
Published: October 2003

We present a brief review of the combined pairing mechanism mediated by phonons and lochons (local charged bosons) for the high temperature superconducting materials (mainly cuprates). The phonon contribution (λ p ) being weak, the lochon part (λl) dominates to give higher critical temperatures (T c ). The combined mechanism along with the variation of λl with carrier concentration (x c ) gives the right variation of T c and the oxygen isotope exponent on doping. The superconducting gap Δ(0) at T = 0, its ratio with T c , the condensation energy, gap anisotropy, pseudogap, etc. are also discussed.

With reasonable agreement with available experimental data, the combined mechanism emerges as a strong contender for an acceptable model for oxide superconducting materials.
Impurity Cationic-Site Population and Electric-Field Gradient Dependence on Ionic Size in Bixbyites Sesquioxides Implanted With 181Hf → 181Ta
Authors: Rentería M. , Bibiloni A. G. , Requejo F. G. , Pasquevich A. F. , Shitu J. , Errico L. A. , Freitag K.
Published: October 2003

The Perturbed-Angular-Correlation technique was used to study the impurity cationic-site population and electric-field gradients in scandium and samarium sesquioxides implanted with 181 Hf → 181 Ta . We found a departure of the tantalum (hafnium) relative occupancy of the crystallographic sites C and D in the bixbyite structure from the natural abundance of the sites, in the case of scandium sesquioxide, that could be explained in terms of the small lattice parameter of this sesquioxide. A similar behavior occurs in the case of indium sesquioxide. In the rest of the bixbyites measured with 181 Ta , f D /f C remains nearly constant and close to the crystallographic abundance, which is only reached in the case of Sm 2 O 3, the sesquioxide with the largest lattice parameter. Additionally, we confirm a jump in the values of νQ( Ta ) for sites C and D that takes place for a ≤ 1:012 nm, that is for lattice parameters smaller than that of ytterbium sesquioxide.
Critical Exponents of α-Irradiated Bi-2212 Superconductors in the Paracoherence Region
Authors: Ghosh A. K. , Bandyopadhyay S. K. , Sen Pintu , Barat P. , Basu A. N.
Published: October 2003

The relation between the excess conductivity and the critical exponent of conductivity is discussed in the paracoherence region. The critical exponents vary with α-particle irradiation of Bi 2 Sr 2 CaCu 2 O 8+x (Bi-2212) superconductors. The role of the Harris' criteria is discussed. The normalized Josephson coupling energy is calculated and its variation temperature is plotted both for the unirradiated and irradiated Bi-2212 samples. Effects of the variation of normalized Josephson coupling energy are discussed in the light of variations of critical temperature and grain volumes.
Coulomb Correlations in Resonant Tunneling
Authors: Bahlouli H. , Zekri N.
Published: October 2003

We study the effect of Coulomb interaction on the average single and double occupancy of a resonant state within an amorphous tunnel junction. Double occupancy occurs only when the width of the energy distribution becomes comparable to the Coulomb interaction. The magnetic field dependence of the normalized conductance does not seem to be sensitive to the magnitude of the on-site Coulomb interaction. Fluctuations in the conductance, on the other hand, are anomalously enhanced in the up-down spin channel when the width of the energy distribution of the localized states is comparable to the Coulomb interaction.
Driving Force Behind the O-Rh(001) Clock Reconstruction
Authors: Sun Chang Q.
Published: October 2003

A novel rhombi-chain network is derived from low energy electron diffraction experimental observations and the recent model theory, revealing that the O-Rh(100) clock-rotation is driven by an electrostatic force arisen from bond formation. Thus the O-Rh bond suffers from tension other than compression, or strain relief. As O -1 evolves into the hybridized- O -2,a Rh 5 O cluster in the c(2 × 2) phase develops into a Rh 4 O tetrahedron and yields the overall (2 × 2)p4g reconstruction. In the (2 × 2)p4g phase, the hollow-sited O -2 defines one Rh + ion and two lone-pair-induced Rh dipoles of its four surface neighbors. The surface atomic ratio (O : Rh = 1 : 2) allocates, therefore, half of the surface Rh atoms to be the Rh dipoles and another half to play dual roles of Rh + ion and Rh dipole. Interactions along the "dipole–dipole – Rh +/dipole – Rh +/dipole" strings create the rhombi-chain at the <11> directions, and a responding bond tension confines the (2 × 2)p4g clock rotation.
q-Deformed Anisotropic Superexchange Interaction, Frustration and GLpq(2)
Authors: Grillo S. , Montani H.
Published: October 2003

We study a suitable q-deformed version of the Moriya's superexchange interaction theory by means of its underlying quantum group structure. We show that the one-dimensional chain case is associated with the non-standard quantum group GL pq(2), evidencing the integrability structure of the system. This biparametric deformation of GL(2; C) arise as a twisting of GL q(2) and it match exactly the local rotation appearing in the Shekhtman's work.1 This allow us to express the frustration condition in terms of this twisting, also showing that effect of the Moriya's vector amounts to a twisting of the boundary condition.
Ground State for the Impurity Calogero Sutherland Model
Authors: Shen Yuelin , Wang Xiuting
Published: October 2003

We propose a Calogero–Sutherland model with an impurity. We prove that when the interaction constants have certain relations, the ground state of the model can be abtained with the aid of a set of generalized annihilation and creation operators. Further we present the differential equation for the excited state, with one special solution given.
Short Time Dynamics of an Irreversible Probabilistic Cellular Automaton
Authors: Tomé T. , de Fel Icio J. R. Drugowich
Published: October 2003

We study the short-time dynamics of a three-state probabilistic cellular automaton. This automaton, termed TD model, possess "up-down" symmetry similar to Ising models, and displays continuous kinetic phase transitions belonging to the Ising model universality class. We perform Monte Carlo simulations on the early time regime of the two-dimensional TD model at criticality and obtain the dynamic exponent θ associated to this regime, and the exponents β/ν and z. Our results indicate that, although the model do not possess microscopic reversibility, it presents short-time universality which is consistent with the one of the kinetic Ising model.
Electrodynamical Like-Charge Attractions in Metastable Colloidal Crystallites
Authors: Giudice E. Del , Preparata G.
Published: October 2003

We show that the recent observation of like-charge attractions in metastable colloidal systems is naturally and quantitatively explained by the collective interactions among the surface electrons of the colloidal microspheres, predicted by QED.
Simple Model for Interface Exciton with a Electron–Hole Separation
Authors: Thanh Ngo Van , Viet Nguyen Ai
Published: October 2003

The new simple theoretical model of Cooper1 for the interface exciton with an itinerant photo-excited hole is studied. The main parameter of the model is the separation d between electron and hole, which are assumed to be con ned in the two planes. By variational numerical calculation, we obtain the values of main parameters of the exciton: binding energies, effective Bohr radius, and oscillator strengths versus parameter d. Checking the applicable of the model, we find good agreement with the previous obtained results. We find also a strong dependence on the separation d and an existence of the "death region" of the exciton coursed by the hole band gap potential.
Transition Metal Ion Substitution into the Cu(1) Sites in the "123" High-Temperature Superconductors
Authors: Tang I. M. , Leelaprute S.
Published: October 2003

The effects of substituting either non-magnetic or magnetic (trivalent) transition metal (TM) ions into the Cu(1) sites in the CuO chains occurring in the "123" YBa 2 Cu 3 O 7-x superconductor are studied. It is assumed that pair condensation occurs in both the 2D CuO 2 planes and the 1D CuO chains, that the exchange of the spin fluctuations (SF) is responsible for the pair formation and that the order parameters in the chains and planes are coupled together by pair tunneling. Just like the case for substitution into the Cu(2) sites, the depressions of Tc due to non-magnetic and magnetic TM ions substitution into the Cu(1) sites are caused by the different ways the two type of ions act on the Cooper pairs. The non-magnetic TM ions suppress the formation of the Cooper pairs through their suppression of the SF-induced pairing interaction while the magnetic TM ions break the Cooper pairs through their sping flipping of one of the carriers. For both types of ions, the suppression of superconductivity is enhanced by the normal scattering process.
Superconductivity in Two Models of Interacting Fermions
Authors: Muthukumar V. N.
Published: October 2003

We point out basic similarities between a toy model of superconductivity proposed by Mattis and Benderski [Mod. Phys. Lett.8, 617 (1994)] and a model of interlayer tunneling. In both models, a gap in the energy spectrum leads to a condensed phase without symmetry breaking. The latter model, however leads to qualitatively distinct features in the optical response.