It is shown that the circle of electron beams will be shifted when off-normal photoelectron diffraction (OFF-NPD) instead of the normal photoelectron diffraction(NPD) is used. For the C(2x2)Se-Ni(001) system, the I-E curves of OFF-NPD has been calculated in terms of the shifted circle to select beams in the case of θ=36°. The correct structure constants of surface have been determined, which confirmed earlier NPD and OFF-NPD experimental results.

Refractive index including linear and nonlinear terms, zero dispersion wavelength and their relation to temperature have been given. Theoretical results are consistent with experimental results.

MHD flow in sheared magnetic field is studied, and a new system of equations has been derived. Theoretical and numerical analysis shows that it implies a strange attractor and the effect of the shear on the attractor exhibits some new phenomena.

The effect of diffraction on the geometry of initially plane acoustic transients propagating in liquids is studied. Theoretical considerations concern the transition from plane to spherical waves upon passing the border between near and far wave zone. Experiments with CO₂-laser-generated acoustic waves in absorbing liquids are discussed. The wavefront curvatures and lateral extensions at different propagating distances in n-heptane are analyzed by high-speed shadowgraphy and measurements with a piezoelectric transducer. Good agreement between theory and experiment is obtained.

Investigations on the nature and states of the defects in single crystal wafers treated with double-gettering technique have been carried out by means of optical microscopy, electron microscopy, electron microanalysis and spread resistance. Phosphorus profile in these wafers was measured. And the effect of phosphorus on defects and resistivity was determined.

The properties of polaritons in a disordered material are studied under the Coherent Potential Approximation. The main results are as follows: (i) The concept of effective wave vector can be used to describe the polariton in a disordered material. (ii) The polariton dispersion in a disordered material is similar to that in a crystalline material. (iii) The polariton lifetime due to the disorder increases as its energy departs from the resonant region.

Based on the idea of “from multiple steady states to oscillation”, a proposal for predicting the existence of inverted hopf bifurcation is put forward and confirmed with a model of modified “Brusselator”.

Some serious difficulties encountered in the usual Cranking Shell Model may be overcome in the Particle-Number-Conserving treatment for the cranking hamiltonian. The variation of the K-structure of low-lying bands with the rotational frequency is investigated.

Mechanical polishing and subsequent thermal oxidation are the indispensable condition for rapid formation of a continuous and highly Cr-enriched layer on the surface of a Ni-Cr alloy. Direct observations of the Cr distribution on the surface by Auger map show a possible process for Cr segregation. The huge amount of grain boundaries created by mechanical polishing promote the upward diffusion of Cr. Selective oxidation and Cr-holding effect also speed up the formation of Cr₂O₃.

A formulation which counts the contributions to the short range nuclear force from both the quark-gluon and quark-pion interactions in the chiral (and the cloudy) bag has been developed. The effective operators are given in terms of the propagators of the quark, gluon and pion fields. The effective potential can be calculated for any anti-symmetric wave functions of six quarks in a cavity. The calculations have been done for DeTar‘s six-quark states and those N-N states which are constructed using group classification and fractional parentage reduction. The results show tkat there is a repulsive core whose strength is about several hundreds MeV in the nuclear potential.

Many electromagnetic phenomena on the surface of a pulsar can be explained successfully by the Arons-Scharlemann model. Yet several related phenomena have not been accounted for. In this study we provide solutions for several hitherto unsolved problems in this model, such as the mechanism for the return currents, the relationships between modes of changing and nulling of pulsars and the source for the observed cosmic ray positrons with energies greater than IGeV. In addition, we propose an explanation for the distribution of pulsar periods.

We report the systematic study of the dynamic Burstein-Moss effect of interband transition in Cd_xHg_1-xTe by CW CO₂ laser. The effective absorption coefficients as a function of incident intensity for different laser lines were demonstrated.