We calcuate lattice constants, volumes, elastic moduli, Vickers hardnesses and density of states of the tetragonal, monoclinic and orthorhombic Ge₃N₄.Fundamental properties obtained are compared with experimental data and other theoretical results, which shows good agreement.Negative formation enthalpy, linear relation between lattice deformation and pressure, and volume show that three phases retain stabilities in a pressure range of 0~20 GPa.Density of states show that Ge₃N₄ are semiconductors with strong s-p hybridizations.All polymorphs are brittle materials but anisotropic.Several thermodynamic properties are investigated with quasi-harmonic approach considering lattice vibrations and anharmonic effects.Helmholz free energy and internal energy show strong dependences on pressure.Interesting features are seen in heat capacity of the novel Ge₃N₄ nitrides, especially at high temperatures.

Based on the cluster multiple labeling technique,a novel cluster detection algorithm is presented as an analysis subroutine in two-and three-dimensional molecular dynamic simulations of ejecta that take place as a planar shock wave encounters a free metal surface.The algorithm is described,tested,and used to detect cluster distribution of ejecta from copper and aluminum under a shock loading.The information obtained about the size,distribution,evolution of the cluster is helpful in the understanding of ejection.

A numerical approach of the iterative conjugate gradient method is developed to solve the volume integral equation of EM scattering. This method is effectively applied to calculate scattering from multi scatterers with large electric scales.

Light propagating through atmosphere will be distorted as a result of the random changing index of refraction along the light Path. This distortion lowers the optics system performance. Wavefront distortion can be compensated and corrected by adaptive optics systems. For real time compensation, systems must respond fast to the changing wavefront information. Three basic reconstruction schems are studied and fast algorithm is proposed using the block and sparse structure of the transformation matrix. Different wavefront reconstructions show that the algorithm is very effective.

The computational program of chemical kinetics of KrF^* excimer laser pumped by e-beam is modified. The kinetics and energy deposition for the mixture system of Ar, Kr and F₂ pumped by proton-beam is calculated. The results show that deposited energy is about 50 times as much as by e-beam-pumping for the same pressure, the same mixture of the gases and the same current density.

In this paper We calculated numerically the electron energy deposition in the cylindrical Ar/Kr/F₂ mixtures Pumped transversely by electron-beam, using SANDYL code, Obtained the relations between energy deposition efficiency and total Pressure of the mixture, electron energy and mixture Composition ratio. Moreover, We made rough estimation of the energy deposition efficiencies of electron and proton by using the formula of the stopping power, and made the comparison of electron and Proton energy losses for the theorical simulation of Proton-beam Pumping.

We have obtained an equation of state at ok by use of the relation between the differential expression and an empirical interpalation expression of the Gruneisen coefficient.We have calculated Hugoniot curves for pb,w,Mo,Fe,Al, the results are in satisfactory agreement with experiments (up to about 5 TPa).The cold pressures abtained are in good agreement with those from From-Mayer potential and improved Morse potential in the range 1≤ρ/ρ_o ≤ 1.5.The two integrals used in calculating cold pressure and cold energy are tabularted

This Paper Presents an approximate method of calculating the ianization degrees, and then an analytic expression of the equation of state for high temperature gases is derived, which can be applied directly to the fluid dynamics calculations. The expression is simple and Its results are fairly accurate.