Dynamics behavior of a vapor bubble such as rising, growth and deformation in superheated liquid was simulated with three-dimensional lattice Boltzmann phase-change model. To study effect of heat and mass transfer on vapor bubble, process of bubble rising in isothermal system was simulated. It shows that deformation extent of vapor bubble is small in superheated liquid. It is suggested that the effect of phase-change on vapor bubble is similar to surface tension force, which makes vapor bubble tend to keep its initial shape. Rising velocity of vapor bubble in superheated liquid was smaller. It implied that the effect of drag force on vapor bubble was dominant in superheated situation. In addition, growth rate of vapor bubble reaches the maximum at initial stage; Then it tended to nearly a constant. As vapor bubble volume and velocity increase, influence of disturbance on flow field is more and more intense. Meanwhile, growth of vapor bubble and convection induced by bubble rising have great impact on evolution of temperature field.

Mechanism of transition delay by porous surface in hypersonic boundary layers is investigated. Linear stability theory (LST) is adopted to analyze characteristics of instability and comparisons with direct numerical simulation (DNS) are made. Under conditions Ma=6.0,Re=2.0×10⁴ (length scaled by displacement thickness of boundary layer),typical flow characteristics are obtained for planar boundary layers with and without distributed pores. Disturbing growth rate of smooth and porous boundary layers are computed by LST. N-factor,which is regarded as a symbol of accumulated growing of disturbance,is calculated. It shows that pores prohibit growth of Mack's mode and therefore delay transition of hypersonic boundary layer. Sequence-distributed pores stabilize boundary-layer flow more effectively than interlace-distributed pores.

A finite analytic numerical scheme is constructed for two-dimensional two-phase flow in heterogeneous porous media. Compared with traditional numerical methods, FAM makes convergence faster as refinement parameter increases, and accuracy is independent with heterogeneity. In contrast, as using traditional numerical schemes to simulate flow through a strong heterogeneous porous medium, refinement ratio for grid cell needs to increase dramatically to get an accurate result. Compared with the proposed scheme, traditional numerical scheme underestimates greatly breakthrough time under coarse grids. However, to get a saturation distribution with high resolution even employing the proposed scheme, relative fine grids are still needed. This is different from FAM for solving a single phase flow, where coarse grids provide rather accurate results.

Electronic and lattice dynamic properties of ternary intermetallic SrAlSi are studied with first-principles calculations based on density functional theory under high pressures. SrAlSi has a similar hexagon-honeycombed structure to MgB₂,where Sr atoms substitute Mg atoms,Al and Si atoms randomly occupy the positions of B atoms. It is found that under high pressure electronic topological transition( ETT) occur in the band of SrAlSi near Fermi surface. Lattice dynamics of SrAlSi are studied by phonon dispersion spectra at different pressures. The calculation shows that optical branches soften along A-L-H line and phonon modes harden with increase of pressure. It is indicated that structure of intermetallic compound SrAlSi is unstable under high pressures.

In order to evaluate network nodes importance effectively, an evaluation method based on efficiency matrix is proposed. Based on node degree and contribution of network node importance comprehensively, the method uses node degree and efficiency matrix to characterize their importance, and to solve deficiency of node's dependence on adjacent nodes only in the method of node importance contribution matrix. Taking actual network sparsity into account,the algorithm has time complexity of O(n²). Finally, feasibility and validity of the algorithm are demonstrated with numerical example analysis. It shows that the method distinguishes node importance differences more directly, simply and effectively. It obtains ideal computing power for large scale complex networks.

Using X-ray imaging to deduce equivalent of nuclear explosion is preliminarily discussed.A characterized ring pinhole geometry model is established.MCNP4C is used.The source area,determinaton of E_c,influence of ring width,equivalent temperature and incident angle of X-rays are simulated.It is poined out that the source area should be selected as S₀=6.25πcm² and E_c=2×10^-8 MeV.Energy response and angle response should be considered.Characterized ring pinhole models at equivalent temperatures 1.4 keV and 3.8 keV and at incident angles 0,1,2,3,4,5,6 degree are simulated.

We present an element free Galerkin method(EFGM) for nonlinear transient field involving phase change.It needs no element connectivity.Compared with other methods such as the finite element method(FEM),it is easy in tracking the growth of phase boundaries.Essential boundary conditions are enforced using a penalty function method.The MATLAB codes are developed to obtain numerical solutions.Two classical examples show that,compared with the FEM,EFGM has more advantages such as high accuracy,good convergence and simple post-process,etc.

To meet the demands of the study of CFCs alternatives and the engineering application,a group contribution method is proposed to calculate the saturated liquid's density of freon in ethane class based on the equation of saturated liquid density of Перелъщтейн.On condition that the critical temperature and critical density or critical specific volume are known,the density of saturated liquid can be calculated with high accuracy.The obtained mean deviation and the maximum one are less than 1% and 15% separately,which can meet the demands of alternatives' studies and application.

It presents calculation of charge cross sections for multi-charged ion 10Ne^q+ collision with neutral atom H and He using Thomas-Fermi Approximation and Binary Encounter Approximation,also calculations of electron momentum distribution and ion potential function distribution.

This paper reviews the works about computer simulation of liquid shear viscosity.The Argon at triple point,considered as sphere molecule with Lennard-Jones potential energy,is numerically simulated with NEMD(non equilibrium Molecular dynamics)method.The results are consistent with those in references.

In this paper, a lattice gas mode! is proposed to simulate gravity. We evaluated the average of gravity and obtained a macroscopic parameter k.When 0≤k≤0.02, The pressure distribution obtained is in agreement with the theoretical predictions.