Conservative scheme in Lagrangian coordination is applied to compute multicomponent fluid dynamics, in which numerical flux of one order scheme is used near interface, while numerical flux of high resolution scheme is adopted in other areas. This scheme not only remains good high resolution, but also eliminates the oscillations due to common conservative scheme.

The electronic structures of impurity in silicon have been studied by SCF-X_α-SW method, it is shown that the electronic structure is depending strongly on the atomic radius in the cluster. We have proposed two rules to determine the atomic radius:1) Adjusting the atomic radius of master element according to the band properties of crystal;2) Determining the radius of impurities in terms of minimizing the total energy of cluster.The calculations of electronic structure of Si:Pd and Si:Pd systemsshave demonstrated that these rules are efficient.