Yang LiMing

A MICROMECHANICAL ANALYSIS OF THE NONLINEAR ELASTIC AND VISCOELASTIC CONSTITUTIVE RELATION OF A POLYMER FILLED WITH RIGID PARTICLES

Micromechanical theory is applied to study the nonlinear elastic and viscoelastic constitutive relations of polymeric matrix filled with high rigidity solid particles. It is shown that Eshelbys method can be extended to the case of nonlinear matrix and Eshelbys tensor still exists provided that Poissons ratio of the nonlinear matrix assumes constant value in deforming process and the rigidity of elastic filling particles is much higher than that of the matrix. A new method for averaging process is proposed to overcome the difficulty that occured in applying the ordinary equivalent inclusion method or the self-consistant method to nonlinear matrices. A rather simple constitutive equation is obtained finally and the strengthening effect of solid particles to composites is investigated.

New Transformation for Treating Pair Correlation and Microscopic Foundation of Interacting Boson Model

For strongly pair-correlated systems, a new transformation is derived similar in form to the usual Bogoliubov-Valatin transformation, but with the transformation coefficients replaced by operators. The original fermion operators are now replaced by two sets of independent operators, the pair operators and the quasi-fermions . The transformation conserves the particle number. Among other applications, it is particularly suited for the construction of a microscopic theory of the type of the interacting boson model. The new transformation given here also serves to provide a connection between the usual ph picture of a phonon and the pp picture-of bosons in IBM. However, the boson picture that evolves from the present formulation differs from the ideal boson picture in IBM..

Extended Quark Potential Model from Random Phase Approximation

The quark potential model is extended to include the sea quark excitation using the random phase approximation (RPA). The effective quark interaction preserves the important Quantum Chromodynamics (QCD) properties -- chiral symmetry and confinement simultaneously. A primary qualitive analysis shows that the

Hamiltonian Approach to Meson Structure in Extended Nambu-Jona-Lasinio Model*

\pi

Charge Exchange Component of n-p Interactions

meson as a well-known typical Goldstone boson and the other mesons made up of valence

Shape Coexistence in Odd-Mass Nuclei near Z = 50*

q\bar{q}

Pair Excitations in Even-Even Nuclei*

quark pair such as the

An Understanding of the Meaning Behind Boson-Description in the Collective Motion of Nuclei

\rho

The Structure of S Pair in Collective States (II)

meson can also be described in this extended quark potential model.The quark potential model is extended to include the sea quark excitation using the random phase approx-imation. The effective quark interaction preserves the important QCD properties - chiral symmetry and confinementsimultaneously. A primary qualitative analysis shows that the π meson as a well-known typical Goldstone boson andthe other mesons made up of valence qq quark pair such as the ρ meson can also be described in this extended quarkpotential model.

FRACTIONAL PARENTAGE COEFFICIENTS FOR COMPOSITE PAIRS

The Nambu-Jona-Lasinio model,is extended to inclusion of the nonlocal effective quark interaction with confinement. An effective Hamiltonian in the instantaneous approximation is used to study meson properties in the random phse approximation.