The Dyson form of the q-deformed boson realization of the quantum group SU(2)_q is constructed. The unitary Holstein-Primakoff representation of SU(2)_q is obtained from non-unitary Dyson representation by means of K-matrix technique.

Some examples of a new kind of the Aharonov-Anandan phase which is of mechanical origin are studied. It is the non-adiabatic generalization of the mechanical Berry phase. We first study the periodic motion and then the interference effect. Finally we discuss the relation between Aharonov-Anandan phase and Berry phase.

The nuclear neutrinoless double beta decay with emission of a Majoron is discussed by means of a diagrammatic effective operator approach. In the calculation, the effects of the nuclear short range correlation and nuclear core polarization have been taken into account. The effetcive Majoron coupling to neutrino is then deduced from the experimental half-life of ⁴⁸Ca double beta decay with the result (gH^o) < (2 ~3) x 10^-4.

Hyperfine structures of La1 are reported using Doppler-free intermodulated fluorescence, Doppler-limited laser induced fluorescence and optogalvanic spectroscopy in a home-made cathode discharge tube. The constants A and B for the levels at 20197.34, 21447.86cm^-1 and constant A for the levels at 19379.40, 18156.97, 94910.38, and 24409.68cm^-1 are reported. A homogeneous linewidth less than 40MHz and the different resolutions between fluorescence and optogalvanic spectroscopy were observed.

The reaction rate coefficient for collision between hydrogen molecular ions and nitrogen molecules has been measured by using ion storage technique. The results are total rate coefficient k=5.68x10^-9cm³/s and rate coefficients k_pt =5.23x10^-9cm³/s for proton transfer and k_ct = 4.5 x10^-10cm³/s for charge transfer.

The differential cross sections and spin polarization parameters for the spin-electrons elastically scattered from spinless Xe atoms are calculated by relativistic partial expansion method. In the processes the incident electrons are treated as moving relativistically in an effective central potential V(r) which is calculated by relativistic self-consistent-field method with Slater local exchange approximations. The validity of the theoretical method can be accessed by detailed comparison with recent complete experimental data.

The dislocations in lithium tetraborate crystal have been investigated by means of synchrotron radiation white beam topography in BSRL (Beijing Synchrotron Radiation Laboratory). The Burgers' vectors of these dislocations are determined by their vanishing conditions. Both screw and edge dislocations exist in the specimen.

In situ observation in high voltage transmission electron microscope (HVEM) was used to investigate the structure of Mo implanted HI3 steel. Instead of tempered Martensite structure, the implanted layer has a fine grain structure. When the implanted specimen is heated inside the HVEM, the fine grain structure does not change until 500°C. The electron diffraction pattern of precipitates FeMo appears at 500°C. Recrystallization and grain growth occur at 650°C.

The influence of γ-irradiation on properties of METGLAS 2605S2 and FC3-1 Fe₇₈B₁₃Si₉ has been investigated by Möissbauer spectroscopy and bending test. The ductility and orientation of magnetization were changed by γ-irradiation. They probably correlated with the change of microscopic free volume and release of stress in the ribbon, respectively.

Phase transitions of the ferroelectric liquid crystal were studied by recording low-frequency Raman spectra and three Raman lines at 15,49 and 93cm^-1 were observed. The intensities of the 15 and 49 cm^-1 modes reduce to zero at smectic C* transition temperature, and in the isotropic phase the 93cm^-1 Raman line with partial frequency shift totally disappears.

The nature of the NH₃ adsorption process on Si(100)-2x1 surface has been studied by DV-X_α (discrete variational X_α method) and ASED-MO (atom superposition and electron delocalization molecular orbital theory) methods. The calculated results show that NH₃ is dissociatively adsorbed on the surface dangling bonds as NH₂(a) and H(a) un'th no activation barrier. But the further decomposion of NH₂(a) to NH(a) and N(a) has been found to have activation barriers of 0.87 and 1.65eV respectively. The bond geometries and electronic structures of these NH₃-derived adsorbed species are described in detail.

A new general formalism of the Kronig-Penny model has been developed in this article. It is shown by using this formalism that, in general, the envelope wave functions corresponding to values of the superlattice wave number other than zero and π/d have mixed parities, the mixing of parities being due to the tunnel coupling among quantum wells.

By undergoing Varma's phenomenological constraints a calculation of the optical conductivity σ(ω) in polaron model has been performed in order to interpret the infrared absorption features in high T_c superconductors. The temperature and phonon relaxation effects have been included. The agreement between our theoretical results and experiments is satisfactory.

A system of diffusion equations of laser induced chain reaction of 1,2-dichloroethane to form vinyl chloride is established. By means of finite differential method, a temporal radial concentration distribution for the product vinyl chloride and Cl radicals in a single pulse is computed.