Brownian Motion Theory of Oxide High-Tc,Superconductor and Inertial Effects of Vortices

The flux dynamics in high-T_c, oxidc superconductors is investigated by using Brownian motion theory, and the inertial effect is studied. Because of the layer structure of the superconductor,the dynamics can be described by the Brownian motion of a particle in a biased periodic potential field.     

Development of Oxidation Sources in Preparation of High-Tc Oxide Superconductor Thin Films Using the Molecular Beam Epitaxy Method

Film preparation of oxide superconductors, mainly of the 1-2-3 (RBa₂Cu₃O_x) and Bi-containing (Bi-Sr-Ca-Cu-O) systems, by evaporation of either metals or metal compounds by low pressure is summarized, with a particular focus on the development of oxidation sources essential to the technique. Oxidizing reagents that enable the oxidation of metal evaporates to take place in high (0·1 to 10_?3 Pa) or even ultra-high (<10_?5 Pa) vacuum are summarized using the experiments of those who tried to apply the molecular beam epitaxy method to atomically controlled fabrication of thin films of the material, especially for device processing. The evaporation in various kinds of oxidizing atmosphere, including the simple method of in situ annealing of the metal layers in oxygen to the more advanced in situ preparation of the films with strong oxidizing reagents such as atomic oxygen, ozone, nitric oxide, etc. along with the thermochemistry of the oxidation of metals by low pressure with these reagents is reviewed.     

Another Possible Phenomenological Model of the Normal State of the High-Tc Oxide Superconductors

A new phenomenological model has been proposed to account for the anomalous normal state properties of the high-T_c, oxide superconductors. Comparison with the assumed one in the marginal Fermi liquid theory is made. Both of them are similar, but also different. It is shown that in a small frequency region of ω < T (T being the temperature), the conventional Fermi liquid picture still holds, while for ω > T the marginal Fermi liquid theory is appropriate.     

RVB-Itinerant P Hole Model for High-Tc Copper Oxides

A model for the high-T_c Copper Oxides is studied. The, localized nature of Cu 3d electrons is described as the RVB quantum spin liquid and the doped O 2p holes are described with an itinerant band. Our analysis shows that the virtual exchange of two spinons induces a pairing interaction between two holes.     

Canonical versus Grand-Canonical Free Energies and Phase Diagrams of a Bipolaronic Superconductor Model

We continue the discussion of a bipolaronic superconductor (resp. an anisotropic antiferromagnet in quasispin formulation) as formulated in a previous work, based on a quantum-statistical, microscopic mean-field model. The grand-canonical thermodynamic limit is compared with the canonical thermodynamic limit in terms of a net of perturbations, becoming singular in the infinite lattice limit. A generalized thermostatistical framework is elaborated which covers model potentials with infinite parts. The function of the limiting free energy density in selecting the (stable) phases with broken symmetry is graphically illustrated. The phase diagrams for the two types of ensembles are shown to differ in the region where both the gauge symmetry and the invariance under sublattice exchange are broken. In particular, the type of the phase transitions, the order of the critical points, and the shape of some phase boundaries are found to depend on the ensemble, which clarifies certain controversial topics for these models. The uniqueness of the limiting Gibbs states with free boundary conditions in all thermodynamic phase regions is proved, and their decomposition into pure phase states in terms of a symmetric measure is evaluated. The field operators of the condensed particles are determined in the representations over the limiting Gibbs states.     

高温铜氧化物超导体的某些新进展评论

文中对近年来有关高温铜氧化物超导体(HTS)的某些重要实验的进展情况作了评述。强调目前处于HTS实验研究应起主导作用的阶段,特别是对HTS电子液体中反常电荷分布的观察,察微观瞬的技术改进实验结果,有助于解决对HTS超导机制的争论。对HTS的应用基础技术提出了建议方向。     

高温超导体氧振模的混合

为解释高温超导晶体的声子Ｒａｍａｎ偏振谱，本文提出两个Ａ＿（ｌｇ）－对称声子模相混的机制。对Ｙ—Ｂａ—Ｃｕ—Ｏ单晶，按偏振Ｒａｍａｎ谱强度比计算了两个Ａ＿（ｌｇ）－振动模的耦合系数。     

An Extended Model for Coexistence of Superconductivity and Paramagnetism in High-Tc Superconductors

In the present work, the total magnetization in superconducting state is separated into critical state and paramagnetic components in terms of an H（x）-dependent magnetic flux density. Utilizing this model, we reproduce successfully M-H curves measured by Sandu et al. [Phys. Rev. B 74 （2006） 184511] and Sandu et al. [J. Supercond. Incorp. Novel Magn. 17 （2004） 701] for different forms of Jc.     

On the Possibility of Chaos in a Generalized Model of Three Interacting Sectors

In this study we extend a model, proposed by Dendrinos, which describes dynamics of change of influence in a social system containing a public sector and a private sector. The novelty is that we reconfigure the system and consider a system consisting of a public sector, a private sector, and a non-governmental organizations (NGO) sector. The additional sector changes the model’s system of equations with an additional equation, and additional interactions must be taken into account. We show that for selected values of the parameters of the model’s system of equations, chaos of Shilnikov kind can exist. We illustrate the arising of the corresponding chaotic attractor and discuss the obtained results from the point of view of interaction between the three sectors.     

The Interacting Boson Model for Anomalous Rotational Bands

The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.     

The microscopic Interacting Boson Model for nondegenerate orbits

The microscopic Interacting Boson Model formalism is outlined and a general procedure is described for deriving the parameters of the model when the valence orbits are nondegenerate. This latter technique involves expanding pair creation operators for J = 0 (or J = 2) correlated pairs in terms of J = 0 (or J = 2) pair creation operators for individual orbits. This expansion enables us to relate matrix elements for the multi-orbit problem to matrix elements for individual orbits for which the well-known Racah-seniority reduction formulae apply. Our calculated results for the parameters of the boson-boson quadrupole-quadrupole interaction show a definite relationship to the underlying subshell structure of each major shell, in agreement with the phenomenological results. It is also discovered that the results obtained using particle states are not the same as those obtained using hole states, due to the truncation scheme used to extablish the correlated J = 0 and J = 2 pairs.     

Pion-Nucleus Scattering and the Interacting Boson Model

A procedure of combining the medium energy scattering theory in the Eikonal approximation with the interacting boson model is proposed to study the pion-nucleus scattering. The channel coupling effects in the excitation of nuclear collective state with ρ^- and ρ⁺ elastic and inelastic scattering are analyzed. The calculated cross sections for the excitation of 2₁⁺ state of ²¹⁸Sn agree with experimental data quite well.     

HT-7UPF导体的设计及其稳定性分析

使用简单地功率和能量平衡关系,分析了CICC(Cable-in-Conduit-Conductor)型超导体的稳定性。为了导体的设计,推导出一些仅含有超导电缆几何因子和导体运行参数的表达式。最后给了一种HT-7U极向场PF(Poloidalfield)线圈导体的设计结果。     

Energy Staggering in Ground Bands of 232Th and 236,238U Nuclei Using the Interacting Vector Boson Model

The ΔI=2 and ΔI=4 staggering parameters of transition energies E_γ for normally deformed positive parity ground bands in ²³²Th and ^236,238U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dⁿE_γ/d Iⁿ of the γ -ray transition energies in a ΔI=2 and ΔI=4 bands, which yielding multipoint formulae. The first order derivative (two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative (five-point formula) is about 0.5 KeV and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes ^236,238U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.     

On the Pseudopotential Model of Interacting Particle and Electrical Conductivity of Fully Ionized Plasma

The value of the Coulomb logarithm, as a determining factor in investigations on the kinetic properties of plasma, is calculated on the basis of effective potentials of particle interactions of dense semiclassical plasma. The expression for the electrical conductivity of dense semiclassical nonideal plasma, which is compared with the results of other authors, is calculated using the Coulomb logarithm. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On Free Energies of the Ising Model on the Cayley Tree

We present, for the Ising model on the Cayley tree, some explicit formulae of the free energies (and entropies) according to boundary conditions (b.c.). They include translation-invariant, periodic, Dobrushin-like b.c., as well as those corresponding to (recently discovered) weakly periodic Gibbs states. The weakly periodic measures are defined through a partition of the Cayley tree that induces a 4-edge-coloring on that tree. We compute the density of each color. We use these densities for computations of free energies corresponding to a weakly periodic b.c.     

Pion-Rotational Nucleus Scattering and the Interacting Boson Model

A procedure of combining the medium energy scattering theory in the eikonal approximation with the interacting boson model (IBM) is proposed to study the pion-rotational nucleus scattering. The channel coupling effects in the excitation of nuclear collective state with π^- and π⁺ elastic and inelastic scattering are analyzed. The calculated cross sections for the excitation of 2₁⁺ state of ¹⁵²Sm agmree with the experimental data quite well.     

Cranking Calculation in the sdg Interacting Boson Model

A self-consistent cranking calculation of the intrinsic states of the sdg interacting boson model is performed. The formulae of the moment of inertia are given in a general sdg IBM multipole Hamiltonian with one- and two-body terms. In the quadrupole interaction, the intrinsic states, the quadrupole and hexadecapole deformation and the moment of inertia are investigated in the large N limit. Using a simple Hamiltonian, the results of numerical calculations for ¹⁵²,¹⁵⁴Sm and ^154-160 Gd satisfactorily reproduce the experimental data.     

On the Higher Order Effects of A Consistent Q Framework in the sd Interacting Boson Model

By utilizing the 1/N expansion technique(ONET),the analytical expressions of low-lying energy spectrum,the deformation parameter and the reduced matrix elements of E2 transitions to the order of 1/N are systematically given for a consistent Q framework in the sd interacting boson model.It is shown that it is important to consider the angular momentum projection in the intrinsic state formalism.