SIMULATION ON LOCAL FLUX CREEP IN TYPE-Ⅱ SUPERCONDUCTORS

Using C programming language, we have simulated the flux creep process in nonideal type-Ⅱ superconductors. Global and local magnetization curves are calculated and the logarithmic time dependence of local magnetic induction B under a constant external field is examined. The effects of nonuniform pinning potential and self-organized criticality (SOC) model on the simulations are discussed. The results show that the main feature of flux creep is the relaxation effect. The form of hysteresis loops is dependent on the magnetic field sweep rate. SOC can account for the occurrence of fluctuation to a certain extent and nonuniform pinning potential can enhance the fluctuation.     

THE THEORY AND MEASURED RESULTS FOR THE DISPERSION OF ACOUSTIC GRAVITY WAVES IN LAYERED ATMOSPHERE

The equation of infrasonic wave taking into account the gravitational effect in moving media isderived,with multi-layer atmospheric model.The equations of frequency dispersion are specified bydivergence of velocty,using a multi-layer atmospheric model.The dispersion characteristic ofacoustic-gravity wave is evaluated.Numerical results have shown that both the phase and groupvelocities are different two,the acoustic and gravity-waves.The dispersion of the acoustic velocitiesare more sensitive to wind.Usually the short period group velocity in downwind can differ aslarge as 10% from that in upwind.In some atmospheric model,the gravity-waves velocities areagain divided to several groups,with different dispersion characteristics.The new results of infrasonicdispersion characteristics agree well with the observations from the nuclear explosion.     

DIQUARK AND △-N MASS DIFFERENCE IN LATTICE GAUGE THEORY

We show that the spontaneous breaking of the chiral symmetry provides a mechanism for lowering the effective mass of spin zero diquark.relative to spin one diquark.This mechanism accounts for the main part of △-N mass difference. Lattice calculation is consistent with the quark-diquark structure of the nucleon.     

A SOLITON PERTURBATION THEORY FOR THE UNSTABLE NONLINEAR SCHR?DINGER EQUATION WITH CORRECTIONS

Based on the Zakharov-Shabat equation of the inverse scattering transform for the unstable nonlinear Schr?dinger equation, for which a perturbation theory with corrections is developed in this paper. All necessary formulae for calculating the scattering data are derived. Based upon these formulae, the effect due to the corrections can be studied. As an example, the correction due to the damping is calculated.     

CALCULATION ON A CLUSTER MODEL FOR THE ELECTRONIC CHARGE DENSITY AT NUCLEAR SITE AND THE ELECTRONIC STRUCTURE PARAMETERS OF α IRON

In order to investigate the M6ssbauer isomer shifts and its related electronic charge densities for some substances, the electronic charge density at nuclear site of a iron have been computed for an octahedral cluster Fe₆ with SCF MS-X_α method. Some other electronic structure parameters of the cluster have also been obtained, such as the orbital energy distri- bution, the electron density of states, the Fermi level and various kinds of electron energies, etc. The cohesive energy of α iron have also been calculated and discussed.     

COMPOSITE FIELD THEORY AND THE STRATON MODEL(Ⅱ)

On the basis of previous papers,this work discusses the theory of composite fields composed of colored stratons.Varicus equivalent representations of the S-matrix elements are given.The formulae for the transition matrix elements between states involving baryons in the theory of Straton Model are derived.Finally,the field- current relations are extended to spin 1/2 baryons and their applications are discussed.     

DISPERSIVE THEORY AND NUMERICAL COMPUTATION OF THE ACOUSTIC-GRAVITY WAVE IN TWO-LAYER MODEL

Based on the two-layer model suggested by Pekeris, a developed theory of the dispersionof the acoustic-gravity wave dealing with a constant wind speed in each layer is discussed in thispaper. From the basic wave equations of the acoustic-gravity wave,the confluent hypergeometic equa-tion for the two-layer model with a constant wind speed is derived,and its general solutions aregiven.We obtain the dispersive equation by utilizing the continuous condition of the vertical veloc-ity of air particle motion and the sound pressure on the boundary between the two layers,aswell as the stiffness condition on the ground.The analytical representations of the phase andgroup velocities are also given. The methods of the computation are given in detail.The results of numerical calculation onthe computer show that the wind speeds have a great effect on the propagation of the acoustic-gravity wave.The phase and group velocities depend on the wind speeds in two layer.Theexcited cutoff frequency of the acoustic-gravity wa     

A RELATIVISTIC EQUATION OF MOTION FOR MANY-BODY SYSTEM(Ⅱ)

A relativistic equation of motion for many-body system is established. The relativistic potential is a certain rearrangement of the irreducible series of many-body B-S equation. Considering the two-body irreducible B-S kernels only the many-body potential is expressed as a sum of two-body ones.     

NEW B?CKLUND TRANSFORMATION AND EXACT SOLUTIONS FOR VARIABLE COEFFICIENT KdV EQUATION

In this paper, with the aid of Lax pairs, a new B?cklund transformation for the variable coefficient KdV equation is found, Based on the B?cklund transformation, only if integration is needed, a series of exact solutions can be obtained. This method is important for finding more new and physical-signficant solutions.     

NEW EXPLICIT AND EXACT TRAVELLING WAVE SOLUTIONS FOR A COMPOUND KdV－BURGERS EQUATION

In this paper, new explicit and exact travelling wave solutions for a compound KdV－Burgers equation are obtained by using the hyperbola function method and the Wu elimination method, which include new solitary wave solutions and periodic solutions. Particularly important cases of the equation, such as the compound KdV, mKdV－Burgers and mKdV equations can be solved by this method. The method can also solve other nonlinear partial differential equations.     

THEORY OF SOLITON GENERATION AND LATTICE RELAXATION IN POLYACETYLENE (Ⅰ) GENERAL FORMALISM

This series of papers is devoted to the theory of soliton and polaron generation in polyacetylene by both radiative and non-radiative processes. In the first paper of this series a general formalism is presented which combines the Lattice relaxation approach for the multiphonon process developed by Huang and many others with the consistency condition in terms of the Bogoliubov-de Gennes equation and the gap equation. The exact adiabatic electron wave functions consistent with the different lattice syimnetry breaking in the initial and final states are used to calculate the transition probability between these multi-electron states. The formalism presented is illustrated by deriving a general expression for the non-radiative decay rate using the steepest descent method in the case of stronc coupling. The theory developed here canbe applied to treating the quantum. transitions between states of differnet symmetry breaking when the multi-electron background effect and the consistency condition are essential.The applications of the general formalism to polyacettyene and the comparison with numerical results and the recent experiments tvi11 be given in the succeeding papers.     

SEMICLASSICAL THEORY IN PHASE SPACE FOR MOLECULAR PROCESSES:FORMALISM BASED ON DYNAMICAL CHARACTERISTIC FUNCTION

A new semiclassical theory is formulated by introducing a newdistribution function to be propagated in phase space.primarily this theoryis intended to describe molecular collisions such as chemical reactions,but     

THE NONLINEAR SCHR?DINGER EQUATION AND THE CROSS-PHASE MODULATION IN ERBIUM-DOPED FIBER AMPLIFIERS

The nonlinear Schr$\ddot{o}$dinger equation(NLSE) in erbium-doped fiber(EDF) was obtained. The cross-phase modulation (XPM) in the erbium-doped fiber amplifiers (EDFA) was studied based on this NLSE and the rate equations. A more generalized form of the propagation equation in EDFA was obtained which included the phase shifts the EDFA induced. An analytical expression was given to the XPM in the EDFA. It was found that the XPM in the EDFA dose not change very much with the wavelength except at the neighboring wavelengths (around 1531 nm) where the absorption and emission cross-sections of the erbium ions reach their maxima, and the XPMs have opposite signs on the two sides around 1531 nm. Furthermore, it was found that the XPM increases with the increase of the length of EDF.     

WESTPAC III HELD IN SHANGHAI AND WESTERN PACIFIC COMMISSION FOR ACOUSTICS FOUNDED

The Third Western Pacific Regional Acoustics Conference(WESTPAC III)washeld in Nov.2-4,1988 at the Magnolla Hotel in Shanghai.The WESTPACIII was co-sponsored by the Acoustical Society of China,the Institute of Acoustics ofAcademia Sinica and the Acoustical Society of Shanghai.298 scientists and engineers from 14 countries and areas,including China,Japan,Korea(South),India,Hogng Kong,New Zealand,Australia,Singapore,USA,GreatBritain,Denmark,Sweden,F.R.Germany and Israel,participated in theWESTPAC III.The opening ceremony was held in the morning of Nov.2.Prof.Ying Chongfu,Chairman of the organizing committee made the opening speech.In the plenary ses-sion,Prof.Hiroya Fujisaki from Univ.of Tokyo,Japan,Prof.A.C.Kibblewhitefrom Univ.of Auckland,New Zealand and Prof Wei Rongjue from Nanjing Univ.,     

GLOBAL EXISTENCE AND BLOW-UP PHENOMENA FOR THE PERIODIC HUNTER–SAXTON EQUATION WITH WEAK DISSIPATION

In this paper, we study the periodic Hunter–Saxton equation with weak dissipation. We first establish the local existence of strong solutions, blow-up scenario and blow-up criteria of the equation. Then, we investigate the blow-up rate for the blowing-up solutions to the equation. Finally, we prove that the equation has global solutions.     

QUARK MASS RENORMALIZATION IN LATTICE GAUGE THEORY (Ⅱ) BARYON MASS CALCULATION

Using the renormalized quark mass m(g) obtained by fixing the ρ meson mass, we calculate the masses of the baryon states as a function of 1/g² in lattice gauge theory with fermions by variational method. The results are in agreement with experimental values in the range of 1/g² between 0.1 to 0.9.     

TURNING-POINT CONVERGENCE-ZONES IN UNDERWATER SOUND CHANNELS(Ⅱ)A GENERALIZED RAY THEORY

A generalized ray solution,which can be used for calculating the acoustic fields near the causticsand turning points,is obtained by using a generalized phase-integral approximation.This solutionhas a clear physical picture and is convenient for the numerical calculation.The caustic structure andthe intensity distribution at the turning-point convergence-zones in underwater sound channels arediscussed in detail,and the simple and widely applicable intensity expressions are given.The theo-retical analysis shows that for high-pass signals and narrow-band signals,the signals received at theturning-point convergence-zones have the same waveform as the emitted signal or its Hilbert transform.     

NEW B$\ddot{A}$CKLUND TRANSFORMATION AND EXACT SOLUTIONS FOR VARIABLE COEFFICIENT KdV EQUATION

In this paper, with the aid of Lax pairs, a new B?cklund transformation for the variable coefficient KdV equation is found, Based on the B?cklund transformation, only if integration is needed, a series of exact solutions can be obtained. This method is important for finding more new and physical-signficant solutions.     

ENERGY BAND THEORY OF HETEROMETAL SUPERPOSED FI山AND RELEVANT COMMENTS ON SUPERCONDUCTIVITY.IN HETEROMETAL SYSTEMS

In this paper a review of our work on heterometal interface and heterometal superposed film is made. We have proposed a method for Calculating their electronic band structure from the first principle; which may be represented by "MTO-IPWO-PWO". The "tail cancellation" condition has been generalized to fit these cases and the energy and fundamental formulas have been derived. With this method as a guide, we have suggested the.rule of "Histant Hybridization Superiority" in the case of heterogeneous metal-metal interfaces and a similar rule -in the case of compounds as the necessary conditions for exploring the high T_c superconductors.     

THEORY OF SOLITON GENERATION AND LATTICE RELAXATION I N POLYACETYLENE (Ⅱ) NOR-RADIATIVE TRANSITIONS

This is the second paper in a series devoted to the theorq of soliton and polaron generation in polyacetykne by both radiative and non-radiative processes. The general formalism presented in the first paper of this series which combines the lattice relaxatipn theory of multiphonon processes with the adiabatic self-consistency condition in terms of the Bogoliubovde Gennei equation and the gap equatibn, is applied in this paper to explicit calculation of the non-radiative decay rate of an electron(ho1e) into a plaron and that of an electron-hole pair into a soliton pair in plyacetylene. A heuristic derivation for the formula of non-radiative decay rate is given to elucidate the physical meaning of the approximation invol-ved in the case of low temperature and strong coupling. The matrix elements between multi-electron states are estimated in the Hartree approximation using the single electron states obtained as solutions of the Bogoliubov-de Gennes equation. The result obtained is compared with the numerical calculations on a discrete model.