Hydrodynamic simulations are performed to study Richtmyer-Meshkov instability (RMI) and material ejection at a metal-vacuum interface using a 2D multi-component elastic-plastic hydrodynamic Eulerian code. Effect of material strength on instability development of roughened surface is analyzed, and relationship between amount of ejected material and saturated bubble amplitude is revealed. Finally, based on RMI theory for elastic-plastic solids, theoretical models to describe critical condition of ejecta formation, total amount and maximum velocity of ejecta from unmelted metals are established.

A state-to-state model is used to simulate thermochemical nonequilibrium nozzle flow of N₂/N mixture. Quasi-onedimensional nozzle flow at reservoir temperature from 3 000 K to 8 000 K and pressure from 1 atm to 10 atm is simulated numerically to obtain flow properties,especially detail vibrational population distribution. Evolution of macro- and micro-properties of nonequilbrium flow during expanding is analyzed. Rationality of two-temperature or multi-temperature approach is investigated for recombination dominating flows.

Isogeometric analysis(IGA) is applied to eigenvalue problem of waveguide with arbitrary cross-section.Weakened equations are involved with NURBS elements from governing equation of waveguide.The computational model in IGA is inherited from a design model in CAD system,which is beyond traditional numerical method with remodeling procedure.Elliptical waveguides with various eccentricities,triangular and pentagon waveguides are addressed as numerical examples.It demonstrates that the preseut method is feasible for eigenvalue analysis of waveguide with either elliptical or polygonal cross-section.Moreover,it yields excellent results with fewer DOFs,and obtains quicker convergence than traditional method.

It outlines the historical and current situations of monitoring of seismic events.According to the seismology characteristics of teleseismic signals from nuclear explosion,their P wave groups are analyzed by joint time-frequency analysis.It proves that,the time-frequency distributions of the NE teleseismic signals'P wave groups are most similar to each other.

Based on the principle of mutual action of micro electric currents in DC arc column and dynamic balance of electromagnetic forces in an arc region caused by spatial current loading wires, mathematical models of numerical simulation are proposed for DC arc deflection, arc deflection control by multi-botton-electrodes and by inclination of top electrode. Computer simulations are performed to investigate the deflection phenomenon and its control.

The Taylor expansion approximate method is deScribed with the precision of the second order, which is used to solve the electrostatic Poisson equation in the region with arbitrary shape. The Roberta rule is applied to obtain the potential distribution on the axisymmetric axle of the physical problem. A set of universal formulae is derived to solve the problem with various,boundary, so that the complexity of the problem is avoided and the simulating code can be simplied much more.

From the map function of orbit radius, an algorithm is presented for determinating the bounds of the integration in the "Conservation-Map" formulae of charge deposition and the precision of charge deposition, and hence makes the "Conservation-Map" method of charge deposition feasible.

The charged particle Fokker-Planck equation including the energy dispersion term is solved with "one-dimension difference method of both the space and the energy". On the basis of the results obtained, the total amount of energy transfer to background plasma and the fraction of energy transfer to the electrons and to the ions are computed. The results obtained are compard with that computed by the ether methods.