With local thermodynamic equilibrium approximation,radial position-dependent energy flux for diffusive supersonic wave in low density filled cylinder or sphere shell structures with high density walls are given. We obtain arched-type distribution of geometric factor versus radius in cylinder and sphere shell structure. Mean geometric factor is obtained from cross-section average of total radiative energy flux. Effect of spherical shell structure on radiation process is much greaterr than that of cylinder structure. Geometrical free path must be considered in simulation of radiative diffusivity or thermal conductivity for sphere shell structures models. A fitted formula of geometric factor according to numerical solutions is given.

Electron resonant characteristics in Liberman's statistical self-consistent INFERNO model are fully studied. Electron resonant states of uranium are calculated at two temperatures and densities. Electron density of states, wave function and scattering phase shift are given in energy interval containing resonance. Phase of wave function in amplitude-phase form changing with energy is also given. Resonant characteristics are the same as in non-relativistic case.

To study influence of diffusion coefficient, relaxation rates, pore component ratio and pore width on NMR T₂ distributions, a complex rock-pore system is simplified to an equivalent dual porosity medium in a mathematical physics model with Bloch's equation. ADI-FDTD and SIRT methods are used in numerical simulations of NMR transversal response and decomposition of NMR T₂ spectrum, respectively. It shows that transversal magnetization vector decay rate is proportional to diffusion coefficient and micro porosity, inversely proportional to pore width and nearly irrelevant to surface relaxation rate. NMR T₂ spectrum hardly reflects pore components and structure as diffusion coefficient is small and pore width is large. Special attentions should be paid to influence of diffusion coefficient and pore-size as evaluating pore structure by NMR.

A method is proposed for choosing electron cutoff energy,which is self-adaptive with cell size,background material and electron position.As residuary range of an electron defined by total stopping power is less than distance to the nearest cell boundary,the electron is killed.Compared with the CUT model used in MCNP program,efficiency and precision of self-adaptation method is higher.The most important is that cutoff energy of electron is selected automatically in program in all models,without consideration of energy of particles or dimension of model.

The Vlasov-Poisson equations are used to simulate the propagation processes of relativistic electron beam (REB) in one plate or two plates.The position of cumulative maximum space charge,the oscillating frequency,of current J,elrctron number density n and electric field E in different positions versus injecting electron number density n₀ and injecting electron velocity v₀ in one plate model,and the inject-ing current J₀ and the distance between the two plates in two plates model are investigated.Numerical results of virtual cathode position are closed to the results given by stable theory.Its oscillating frequency is in agreement with the empiric expresion (1~√2π)ω_peb.Numerical simulation result for injecting elec-tron beam density having Guass distribution for volecity,spread of energy ΔE_n/E_n < 10% appears to be in largely conformity with the conclusion of monoenergy case in one plate model.

A finite difference beam propagation method (FD-BPM) is analyzed and assessed for the application to two-dimensional structures.The general formulations for the FD-BPM are derived form Maxwell equations for TE mode and TM mode respectively,with the transparent boundary condition (TBC).The FD-BPM is assessed by computing the loss caused by the numerical error and the percentage error of the propagation constants of the TE and TM modes of a step-index slab waveguide.Based on this assessment,FD-BPM appears to be a good tool for the analysis and simulation of the optical waveguide devices and a exellent method for the computer-aided-design in Integrated Optoelectronics.

The time-dependent quantum mechanical method applied to inelastic atom-molecule scattering is presented and examined in interaction picture. The method is not only extremely accurate but is more efficient than the CC method.

The virtual cathode oscillation in relativistic electron beams is studied by a 1-D electrostatic particle simulation code with the finite-size-particle model. The calculation results show following conclusions; When injection current is less than the space charge limiting current, cicctron beam propagates stably and transsmits completely. When injection current exceeds the space charge limit, ils propagation is unstable, a part of electrons reflect and the other electrons transsmit. The position and potential of the virtual cathode caused by space charge effects oscillate periodically. When the beam current increases, the virtual cathode position is closer to the injection plane and its oscillating region gets narrower, the virtual cathode potential decreases and its amplitude increases, the oscillation frequency increases above the beam plasma frequency.

The problem about a projectile with high veiocity impacting on a target is an important subject in penetration mechanics, It is also an important question in Studying dynamic response of materials.In this paper,the calculations of cylindric steel projectiles impacting on Aluminum targets have been performed using the dual lagrange APHEMP code and the results are compared with the experiments the dynamic picture of the impacting processes is preliminarily Studied.

Plasma particle simulation wave spectral response to electrostatic wave is systematically analyzed. We introduce the wave spectral-response function of plasma particle simulation.The response expre-sion in following case is derived respectively, Finite-Size-Particle with Gauss, triangle and square shape, its dipole expansion near grid point, finite difference and FFT solving process of Poisson equation. The influence of shape, size and treatment of Finite-Size-Particle, space discreteness and solving process of Poisson equation on particle simulation spectral response and the depression of short wave noise are discussed.