To analyze force of fluid on a rigid object near free surface,a mathematical model with free surface effect is developed based on potential flow theory.It is calculated with boundary element method.Nonlinear kinematic and dynamic boundary conditions are taken into consideration.With control equation and boundary conditions,piercing cylinder through free surface and phenomena of spike are simulated.A comparison between numerical and experimental results shows that the method is appropriate.Pressure on moving objects,transform of free surface,resultant hydrodynamic force and velocity of flow field are analyzed in detail.It shows that the nonlinear method with free surface effect predicts precisely force on moving objects in vicinity of free surface.

Ab initio restricted Hatree-Fock(RHF) calculations, Moller-Plesset correction calculations of the correlation energy, and the density functional theoretical calculations using B3' exchange and Lee-Yang-Parr's correlation functional(B3LYP) with 6-31G^** basic set are compared by optimizing the equilibrium structure of CD₄ and CH₄ and studying their fundamental vibration frequencies. The results are better than HF's, which are obtained by MP2, DFT, MP4 methods. But MP4 method needs too much CPU time. B3LYP is the best choice. The range of relative errors is from 2.0% to 10.4% between the calculated fundamental vibration frequencies and the observed ones.

The application of database technique for solving some problem in high energy physics analysis is discussed. By designing a connection program between the SQL language database and the software package PAW(Physics Analysis Workstation) commonly used in high energy physics analysis, the data processing capability, conveniency and practicability of PAW are greatly increased. This shows a new application field and prospect of databese technique in offline data physical analysis.

The finite element method(FEM) is employed to calculate potential distributions of two-dimensional current fields in semiconductor sheet resistance measurements using a four-point probe and the model of calculation is presented, which has been tested and proved by calculating the potential distribution of several measurement shaped-samples. The FEM has characteristic of simpler and more common for any shape samples than the methods of electrical image and map transformation.