In this paper we provide a compact version of the effective theory of pseu-doscalar mesons. Our way of representing the θ-term is different from previous ones in the literature. Yet no gauge fields appear in this model, it bears many other underotood features of the underlying QCD, such as large ŋ mass and, if θ≠0, non-zero ŋ→ 2π decay amplitude.

The chaotic behavior of a cubic-quintic nonlinear Schrődinger equation has been discussed numerically. It is shown that the quintic Hamiltonian perturbation leads to the integrability of system broken down.

Determining the parameters in the i-th order approximation in the cumulant expansion from the requirement that the correction to the zeroth order approximation is zero or the smallest, we show in the example of calculating the Polyakov line < L > of U(1) gauge model at finite temperature with N_T = 1-to 5-th order that the expansion works well not only in the strong and weak coupling regions, but also in the intermediate coupling region except the very vicinity of the phase transition point. The calculated < L > is in agreement with Monte Carlo simulations.

A simple version of coupled channels approach is generalized to the light system ¹⁶O + ^16,18O for subbarrier fusion study. It shows that the contribution of the inelastic channel of 2⁺₁ state in ¹⁸O is small, while neutron-pair transfer reaction channel of vanishing Q-value is required to explain the trend of the existing low-energy fusion data.

Using a tight-binding approximation, we have calculated the electronic structure of the suggested CBN ball created from buckyball C₆₀ in which 48 carbon atoms are replaced with 24 boron atoms and 24 nitrogen atoms.

A laser model which may operate in the absence of population inversion is proposed. It is found that the realization of lasing without inversion in this model is due to the change of noninversion condition along with the creation of atomic coherence, instead of a coherence-term-induced gain enhancement.

We have demonstrated a radiation amplification without population inversion in sodium according to a four-level model, which was recentlyproposed by Nor-ducci et al. The amplified radiation signal at 589.0nm has been observed when an intense coherent driving field at 589.6nm was on and an incoherent pumping process from the ground state 3S_1/2 to 3P_3/2 excited state was operating.

Under the resonant excitation of Zn atomic 4p³P₁ state a strong stimulated emission at 481.0nm is produced, which corresponds to the transition between 5s³S₁ and 4p³P₂ of Zn. If N₂ molecular gas is used as buffer gas instead of rare gas He or Ar, the stimulated emission may be enhanced by several orders of magnitude. The dependences of intensity on density of atomic Zn and N₂ pressure are studied experimentally. The mechanism which causes population inversion is propased.

This paper presents the thermoluminescence (TL) and the absorption spectra of a series of doped Bi₄Ge₃O₁₂(BGO) crystal irradiated by ultraviolet light. By the representation of Fe : BGO and Mn : BGO, the formation mechanism of two kinds of deep TL traps was discussed, and also their association with the stability of color center.

Experimental evidence has been obtained to support the applicability of the conduction mechanism, namely two-phase model proposed by Sheng [Phys. Rev. Lett. 31 (1973) 44], for the polyimide films subjected to high-energy-ion irradiation. The spectra obtained by resonant Raman spectroscopy can be well interpreted in terms of this model.

Double-crystal x-ray diffraction has been used to measure the rocking curve of Ta/Al multilayers. The diffraction profiles of the multilayers are different. Besides the normal profile, two kinds of distorted profiles have been found. The simulations show that the deformed profiles of the peaks are caused by the imperfect periodicity (e.g. systematic period deviation and coexistence of two slightly different periods) in the multilayers.

A new class of 1D quasiperiodic lattices, for which the substitution rules are B→BA, and A→BAB, has been studied in several aspects. The high-dimensional projection method for obtaining the quasilattice is presented. A multifractral spectral behavior and gap fabeling properties have been found, which display the perfect quasiperiodicity of the studied model.

Susceptibility measurements on Bi₂Sr₂CaCu₂O₈ single crystals do reveal field-induced-suppression of sharp phase transition. No apparent anisotropy of the susceptibility was observed when magnetic field was applied along the three main directions a, b and c. The three dimensional isotropic fluctuation diamagnetism theory is proposed to explain our experimental finding of isotropic susceptibility. In a wide range of magnetic field, the temperature dependence of susceptibility does not show any obvious change in its character when the sample enters into expected vortex-lattice state from vortex-liquid state.

The effect of the nitrogen on the magnetocrystalline anisotropy of the Sm-sublattice in Sm₂Fe₁₇N_x compounds has been calculated with the single ion crystal field model. The effects of the nitrogen atoms at different interstitial sites on the anisotropy of the rare earth sublattice have been discussed.

The degradation of C₆₀ in organic solution by light has been reported by Taylor et al. [Nature, 351 (1991)277]. The powders of the mixture of C₆₀ and C₇₀ prepared by arc heating ofgraphite electrodes in the environment of He gas was not to be stable with respect to intense irradiation of argon laser (488.0nm), as monitored by Raman spectrascopy, C₇₀ is found to be first decomposed into fragmentary graphite, then C₆₀ followed suit. It is interesting to note that besides graphite, some traces of diamond-like structure are shown confirming some speculations of Mackay [Nature, 352 (1991) 762]

We present the renormalization group of the generalized Fibonacci lattices associated with the aperiodic sequences as constructed by the inflation rule: {A,B} →{AⁿB^m,A}, in which m and n are positive integers. The derived renormalization group consists of 2n(n+ m - 1) + 1 basic renormalization-group Mtransformations. By suitable combinations of these basic transformations, the local electronic properties of the generalized Fibonacci lattices can be exactly obtained.