Based on density functional perturbation theory, phonon properties and electron-phonon interaction in Bi₄Se₃ film system are studied with first-principles calculations. It shows that dynamic of Bi₄Se₃ film system for two terminations is stable. There exists mismatch in projected phonon density of states between Bi₂ bilayer and Bi₂Se₃quintuple layer. It prevents part phonons to transport in Bi₄Se₃ film, which leads to thermal conductivity reduce and improves thermoelectric performance of material. Besides, electron-phonon coupling constant of Bi₄Se₃ film in two kinds of termination are small (about 0.278), which is in favour of electronic device in room temperature.

Adsorption of methane in graphite slit-pores and effect of slit-pores width and temperature on methane adsorption were studied with molecular dynamics simulation. It indicates that methane molecules have layering phenomenon in graphite slit-pores. Structure of methane in adsorption layers shows similar characteristics of liquid while to those of gas in free layers. And in a methane molecule there always exist two hydrogen atoms in a plane that parallels to slit-pore wall and other two hydrogen atoms in another plane that also parallels to slit-pore wall in the first layer. Potential of mean force between carbon atoms shows that binding capacity of methane is stronger in adsorption layers than in free layers. Adsorption state is one of the main occurrence state of methane in graphite slit-pores. London force and electric field force generated by net charge in adsorption layers are dominating reasons of methane adsorption and layering. Adsorption capacity of methane in graphite slit-pores decreases with increasing pore width or temperature. Methane is persisted only in adsorption state in slit-pore with width of 16.46 Å. Diffusivity of methane is the weakest in the first layer and the strongest in a free layer. Diffusion coefficients of methane increase with increasing pore width or temperature.

Monte Carlo simulation on electron transport in nitrogen glow discharge between drilled electrodes in a plasma ion source is presented.Collision probabilities of electron-molecule,average energy and exit angle of outgoing electrons are calculated.Energy distribution of electron calculated follows approximately Boltzmann distribution.With increasment of E/N,electron average energy and probabilities of electric excitation,dissociation,ionization,dissociative ionization collisions are increased.Nonuniform electric field between electrodes enhances ionization rate and electron average energy obviously.

With properties of non-negative operator and Lax-Milgram theorem, we transform an ill-posed 1D heat conduction problem into a well-posed second kind Volterra equation, and introduce a stable and fast algorithm. Related theoretical analysis is shown. For the determination of regularization parameter, the algorithm employs two posterior strategies, which can be realized quickly whether the error level of input data are known or unknown. Numerical tests demonstrate merit of the algorithm.

Numerical calculations on Josephson junctions under microwave radiation are made by means of Runge-Kutta method in the RSJ model. The DC I-V curves of Josephson junctions reproduce experimental results very well.

The numerical generating method for global homeomorphic grid from multi-dimensional towel-shaped reality region to square computational region is investigated. The numerical iterative method for multi-dimensional equal-parameter transformation is given. Its error analysis and the sufficient condition of numerical grid without overlapping is pressented. Finally, an example about two-dimensional non-overlapping numerical grid generation for Qiantang Estuary is shown.

The hydrodynamic surface instabilities driven by X-ray ablation in Inertial Confinement Fusion(CIF)have been analyzed,and the role of Raleigh-Taylor(RT) instabilities in CIF has been also discussed.Based on one dimension numerical computational results,according to the formula of net growth factor at the ablation surface,the net growth rates of RT instabilities have been estimated.Finally,some recommendations for instability experiment are proposed.

Main processes involved in the laser-target coupling are described,including the absorption of laser light,heat conduction of electron,plasma motion,nonequilibrium ionization,laser X-ray conversion and the radiation transport.It outlines the numerical simulation,presenting the partial differential equations,constructing the finite difference schemes and describing the solving methods.Finally,some calculated results are given.

The low phase error FCT numerical algorithm is introduced,and used to simulate Rayleigh-Taylor(RT) and Richtmyer-Meshkov(RM) instabilities.Simulation results agree well with the linear theories of RT and RM instabilities and the calculation of the shock tube experiment of Russia.It shows that the FCT method is fit to simulations of instabilities of ICF problems.

The paper presents the main processes of physics and the outline of the computational program related laser X-ray conversion, gives the typical pictures and numerical results. Based on numerical simulations, the laws of some important properies of physics are obtained, the results estimated by the scaling lasw are in comparison with the measurement values, they are coincident each other on quantitative tendency and quantitative results.

The geometric buckling is of great value in application to criticality problem and analysis of dynamic process of supercritical system in fast fission reactor. The geometric buckling of bare reactor of homogeneous ellipsoid is solved analytically with variational method, and the deductive process is given in detail in this paper, We also apply the solution to bare reactor of inhomo-geneous ellipsoid and infinite reflected reactor. The analytical results agree quite well with the ones of 2 dimesion numerical simulation.

In design of hohlraum targets, the design of laser beam inlet is one of the most important problems. Because the mattar on the edge of inlet is heated by laser when-laser is injected, the matter expands isothermally to the inside of the inlet and finally the mattar in the inlet inhibits the laser from coming into the inlet. This is the closure phenomenon. Since the numerical simulation of the closure is two or three dimesion calculation, it is usually very difficult.In this paper a simple physical modle of the plane inlet target has been developed to compute closure time and ratio of injected laser energy in a very large,range of laser parameters.The qualitative tendency and the experienced dependence of the injected laser energy ratio versus the radius of inlet and the laser parameters have been obtained on the basic of numerical computations.The experienced formula of the threshold radius of inlet versus laser parameters has also been compared with the values of experimental measurement of plane inlet targets. The injected ratio is agreed within the order of 25%.

When matter,especially high Z-element, is heated to high tempersture, it will be ionized many times. The degree of ionization has a strong effect on many plasma properties.So we need an approximate method to calculate mean ionization degree in many practical problems.In this paper, an analytical expression which is convenient for the approximate numerical calculation, is given by fitting it to the scaling law and numerical results of the ionization potential of Thomas-Fermi statistical model⁽¹⁾. In LTE case, the degree of ionization of Au calculated by the approximate method of Ref.(2) is in agreement with that of the averageion model. By extending the approximate method to Non-LTE case, the degree of ionization of Au is similarly calculated according to Corona model and Collision-Radiation model(C-R). The results of Corona model agree with the published data⁽¹⁾ quite well, while the results of C-R approach those of Corona model as the density is reduced and approach those of LTE as the density is increased. Finally, all approximately calculated results of ionization degree of Au and the comparision of them are given in figures and tables.

This paper presents a method of solving low Reynolds number non-linear flow past a body. To be based on Oseen's equation, the effect of non-linear terms is considered by successive iteration. First, we write Navier-Stokes equation as Oseen's equation,with a forcing function (i, e, non-linear terms);then,this equation solution is given by a integral form of the ‘Oseenlet’. It is a non-linear integral-differential equation which involves a body surface integral and a flow space integral. Let distributive intensity of the ‘Oseenlet’ on the surface be unknown. They are decided by the boundary condition. Since the Space integral depends on the flow field which is not known prior to solution, an iterative scheme is used. The iterative process continues until a convergent solution is complete.This method is used to evaluate the drag acting on a single cylinder in uniform flow until Reynolds number Re=10. The obtaining results is-compared with the experimental data and the related results. It indicates that the present method is satisfactory.