1989年, 第11卷, 第3期　
刊出日期：1989-04-30

  

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  The Calculationp of Pressure-Induced Shifts of R Line and Two Bands of MgO:Cr³⁺

  MA Dong-ping, ZHENG Xi-te, CHEN Ju-rong, ZHANG Zheng-gang

  理论物理通讯. 1989, 11(3): 249-254.

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  Based on the conception of electron radial wave function expansion under pressure, by making use of the expansion function φ(κ), B,C and Dq as functions of κ, with the configuration interaction considered, theoretical calculations of pressure induced shifts of R line and two bands of MgO:Cr³⁺ are given in a unified way. Results agree well with experimental data.
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  Gelation in Generalized Smoluchovski Equation

  YU Jiang, HU Gang

  理论物理通讯. 1989, 11(3): 255-264.

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  We consider a system of substances A_j reacting according to the scheme: A_i + A_j +A_k A_i+j+k, which is described by the generalized Smoluchovski equation. We discuss the existence of global solutions of this kinetic equation, and show that the total number of monomers may decrease as the result of the formation of infinite clustere (gelation) for some special coagulation kernels. We also solve the case R(i, j, κ) = s_is_js_κ with s_κ = Ak + B explicitly, and find that the gelation indeed occurs at t_c = (6A + B)/6A²(A + B)².
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  Bifurcation Spectrum in a Delay-Differential System Related to Optical Bistability

  LI Jia-nan, HAO Bai-lin

  理论物理通讯. 1989, 11(3): 265-278.

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  A delay-differential system related to OB or HOB device is discussed in this paper. We obtained the instability conditions for the steady state and the critical relations among the parameters T and μ for the ω_n modes by solving the characteristic equation of the system. Baaed on the numerical result the chaos and bifurcation "spectrum" in the (T, μ) plane was ehown for a simple model equation Tdx(t)/dt = -x(t)+1-μx²(t-1) when higher modes were neglected. We discovered the coexistence of two different kinds of attractore for this equation in a certain region of the parameter plane.
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  Self-consist ent Semiclassical Appoach to Fusion Barrier in Frozen-Density Appoximation

  Guo-qiang LI, Gong-ou XU

  理论物理通讯. 1989, 11(3): 279-283.

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  Fusion barriers of heavy-ion collisions are analysed in frozen-density approximation, with ground state density of each colliding nucleus determined by a self-consistent semiclassical (SCSC) calculation. Spin-orbit contribution to the nucleus-nucleus optical potential is included, while exchange effects on kinetic energy density and spinorbit density are neglected. The calculated barriers are in agreement with experiments.
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  Self-consist ent Semiclassical Approach to Giant Resonances on Deformed Nuclei

  Guo-qiang LI, Gong-ou XU

  理论物理通讯. 1989, 11(3): 285-290.

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  The self-consistent semiclassical approach is extended from spherical nuclei to deformed nuclei. Ground states of several deformed nuclei are determined with this approach. The properties of giant resonances for the deformed nuclei are studied with the help of the above determined ground states in Vlasov framework. The doublepeak splitting of GDR and GQR are evaluated. The reeults are in good agreement with experiments.
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  Normally Ordered Form of Smoothed Wigner Operator and its Applications

  Hong-yi FAN, Guo-liang TONG

  理论物理通讯. 1989, 11(3): 291-297.

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  Using the IWOP (integration within ordered product) technique, we derive a normally ordered form of the smoothed Wigner operator with which the smoothed Wigner function, that is specified only in the integral form in the literature, can be simplified. The application of the new form of the smoothed Wigner operator to the coherent state is also presented.
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  Chiral Syqmetry Restoration in Lattice Gauge Theory

  He-shan SONG, AN Ying, Xue-qian LI

  理论物理通讯. 1989, 11(3): 299-306.

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  The pion mass& calculated starting from the strongly coupling effective Hamiltonian for Wilson fermions by using Green function method. The possibility of the chiral symmetry restoration at a critical quark maas is also investigated.
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  B-B Mixing in Dynimically Broken Theory

  Wang-chuang KUO, Gong-ru LU, Bing-lin YOUNG, Zhong-yuan ZHU

  理论物理通讯. 1989, 11(3): 307-317.

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  The B_d-B_d mixing is investigated in a dynamically broken electroweak theory such as the minimal technicolor theory with a monophagic coupling of quarks and pseudo-Goldstone bosons. The contrbutions of the technicolor pseudo-Goldstone bosons, enhanced by QCD color fowors, dominate the process for a wide range of parameters. If the topdown quark Kobayashi-Maskawa matrix element is not near the minimal allowed value, the pseudo-Goldstone bosone plus W boson can adequately account for the observed mixing large of the pseudo-Goldstone boson and top quark mass.
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  The Magnetic Model of Accretion Disk and the Overstability of .Radial Oscillation

  YANG Lan-tian, YANG Zhi-liang, XIE Guang-shong, LIU Chao, YANG Pi-bo

  理论物理通讯. 1989, 11(3): 319-328.

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  We put forward, in the essay, the assumption of the magnetic model of accretion disk with magnetic viscosity. Optically thick, is the disk whose radiation is thermal in the outer region, while in the inner region it is optically thin and the radiation mechanism is synchrotron. From this we derive the general dispersion relation of the accretion dik for the radial oscillation and discuss the stability and overstability in each region of the disk. The conclusion, therefore, is reached that the accretion disk is globally stable and locally overstable. The global stability may avoid the break of the disk, and the local overstability can cause the optical variation on a short-time scale. Calculating the time scale and the magnitude of the variation caused by the overstability, we get the result which fits well the observed result of BL Lac. objects.
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  Single-Particle Potential of Neutron Matter in a Relativistic Hartree-Fock Approximation

  YANG Yin-li, GAO Shang-hui

  理论物理通讯. 1989, 11(3): 329-336.

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  We calculated binding energy and single particle potential of neutron matter under absolute zero and finite temperature with relativistic Hartree-Fock approach. Our results accord with what thought about on theory.
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  On the Spin-Bag Theory of High T_c Superconductivity

  SU Gang

  理论物理通讯. 1989, 11(3): 337-341.

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  The properties in the spin-bag mechanism of hige T_c superconductivity are studied in the SDW background. It is found that if the Coulomb repulsive potential is much smaller than the valence-band width and is not beyond a particular range determined by the bag energy, two doped holes can be pairing via sharing a common bag. The transition temperature has a maximum value of the order 200 K for reasonable parameters but is independent of doping concentration. In addition, the ratio of the energy gap to T_c is found to be the same as the BCS value. Finally, the specific heat jump at the transition temperature, the coherence length and the upper critical field are roughly estimated.
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  An Analysis of Infrared Stimulated Current in a-Si:H Based on a Model of Three-step Excitations

  LIU Xu-feng, XU Zheng-yi

  理论物理通讯. 1989, 11(3): 343-346.

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  An analysia of the infrared stimulated current in a-Si:H is presented based on a model of three-step excited processes. Since the photon energy of the infrared (i.r.) stimulated beam is less than half of the band gap, generation of tho photon current under the infrared illumination is originated from the mechanism of a three-step excited process. To match with the experimental result, we find that the excitation rate b^′ from the lower localized atates to the higher localiied states In the band gap is much smaller than that from the valence band to localized states and from localixed atatee to the conduction band. The steady state value of the density of the free carriers only depends on b^′, average recombination time γ and density of localixed states g(E).
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  The Low Freqdency Properties of the Forced Brusselator

  JIANG Shao-zhou

  理论物理通讯. 1989, 11(3): 347-350.

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  The low frequency properties of the forced Brusselator with driving frequency ω < ω_c are computed numerically, where ω_c, is the frequency of the motion of the state along the free limit cycle in the phase space. It shows a period-N bifurcation. The asymptotic velocity of the convergence of the period-N bifurcation was found.
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  The Shift Operators in Ginocchio Model

  LING Yin-sheng, ZHU Zheng-kun, JI De-huang

  理论物理通讯. 1989, 11(3): 351-357.

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  In fermion space, the vectors (s⁺|0) and D⁺.D⁺|0) are not orthogonal. The analytic expressions of the wave functions in Ginocchio model are more complicated than those in IBM. Using the shift operator method we can easily construct the wave functions in Ginocchio model. The wave functions of the (0,0) irreducible representations of SO(5) for nucleon number N ≤ 10 are given.
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  The Analytical Wavefunctions of SU(3) Limit in the Interacting Boson Model

  SUN Hong-zhou, LONG Gui-lu

  理论物理通讯. 1989, 11(3): 359-362.

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  A projection method to calculate the physical states from intrinsic states is put forward. Using this projection method, the physical states of the ground state band in the interacting boson model (IBM) SU(3) limit are calculated. The wave functions are expressed in terms of the building blocks of the IBM wave functions.
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  Contribution of Electron-Positron Vacuum Polarization to Energy Level of Exotic Atoms

  A. Karimkhodzhaev, ZHENG Xi-te

  理论物理通讯. 1989, 11(3): 363-366.

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  Energy levela of (ππ)-,(πK)-,(KK)-, - and (πμ)- exotic atoms are calculated in the framework of Logunov-Tavkhelidze quasipotential approach. The analytic expressions for the contributions of electron-positron vacuum polarization are derived. Corrections from strong interactions are calculated according to the formula Deser.
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  On the Dual Symrnetry in Two-dimensional Field Theory

  ZHANG Li-ning

  理论物理通讯. 1989, 11(3): 367-370.

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  Discrete and continuous dual symmetry is analysed and explained in its geometrical origin. Linear eigenvalue equations of the dual transforming operators U are deduced in different forms in a suitable gauge, under the gauge transformation. Different dual parameters are compared too.
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  Correlation Functions in String Multiloop Calculations

  ZHANG De-hai, HUANG Chao-shang

  理论物理通讯. 1989, 11(3): 371-375.

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  Some simple principles are suggested to write down explicitly the correlation functions appeared in the string multiloop calculations, and a little extension of the Riemann vanishing theorem is presented.
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  Magnetic Form Factors of ³He and ³H in the Hybrid Quark Hadron Model

  MA Wei-hsing, Leonard S. Kisslinger

  理论物理通讯. 1989, 11(3): 377-378.

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  Althuough the traditional nucleon picture of nuclear structure does a good job at low momentum transfers for describing basic features of nuclei, there are many strong signals for multiquark clusters in nuclei. In particular, at higher momentum transfers the quark degrees of freedom play a major role in explaining many processes.