Based on the Mie scattering theory and the gamma size distribution model, 10.6μm laser scattering characteristics in dust particles are calculated and analyzed.On this basis,the time broadening and space broadening characteristics of the laser are analyzed by using Monte Carlo method.Transmittance change with the transmission distance are quantitative calculated and the time detention and space broadening characteristics of the laser passed through dust for different transmission distances are calculated and analyzed. The results show that the transmittance decreases with increasing transmission distance, and the transmittance is close to 0 when transmission distance is close to 200m; The time delay of 10.6μm laser is more significant with the increaseing transmission distance; The space broadening of 10.6μm laser is more obvious and the energy is more dispersed with the increaseing transmission distance.

The electronic structure expression of graphene was derived using tight-binding approxi-mation method. According to periodic boundary conditions in width direction of graphene nanorib-bons wave vector, the electronic structure analytical expression of armchair graphene nanoribbons was deduced, and the energy band curve were given. The conditions of graphene nanoribbons being metal or semiconductor were obtained. The results show that when nanoribbons width meetsL=3na/2, the energy gap is zero and armchair graphene nanoribbons behave as the metallic. With the increase of the nanoribbons width, the energy gap of semiconducting nanoribbons decreases. The electronic properties of graphene nanoribbons are closely related to their geometry. The graphene nanoribbons can be modulated into metal or semiconductor with different band gap by controlling their width.

On the basis of the theory of electromagnetic wave propagation in monolayer construct of left-handed material(LHM) and right-handed material (RHM), a calculation method based on recurrence is proposed, this method can be used in the computation and forecasting of the absorbing efficiency of multi-layer materials .Then, the results are consistent with another derived from traditional transmission-line method. But compare to the later, the new calculation method is simpler and more direct. Furthermore, using in Structure consisting of LHM and RHM is also referred. At last, we use this model analyzes the effect by the LHM’s electromagnetic parameter to absorption, from that, we obtain some useful conclusions. Our research results indicate that when LHM is combined with conventional RHM to form a LHM-RHM double-layer structure absorber, the reflection loss will be increased and the absorbing band will be widened. This indicates that the LHM is hopeful to be one of the wave-absorber composite materials, which has better absorbing effect.

The analysis of magnetic field in high temperature bulk superconductors is presented in this paper. The macroscopic field equations were constructed on the basis of the critical state model and levitation forces ware analyzed between permanent magnets (PM) and HTSC using analytical method. The levitation force between permanent magnets (PM) and HTSC calculation were obtained by using Lorentz force equation [1]. The analytical results show that the presented method is comparatively accurate by comparing the measured levitation forces and the calculation ones. Some relations between B(r, t) and levitation force’s hysteresis are investigated.

Recent achievements in III-nitride semiconductor structures growth have allowed ultraviolet (UV) photo-detectors based on these compounds to be well established today. In this article, AlGaN film of 1-μm thickness was grown on Al2O3 substrate by metal-organic chemical vapor deposition (MOCVD). The AFM was used to analyze the surface morphology of the AlGaN film; X-ray diffraction measurements were used to study the quality of the film’ crystal structure; Cathode-ray luminescence(CL) was employed to study the luminescence properties of the AlGaN film. The result shows that there is a single atom layer on the AlGaN film’surface, and it shows that a low-defect-density AlGaN film with good surface morphology and single crystal Hexagonal structure has been obtained. It is found that there is some relationship between the film’crystal structure , dislocations and the luminescence properties . PACS: 73.61.