With first-principles pseudo-potential plane-wave method, crystal structures, electronic structures and optical properties of sulvanite compounds:Cu₃VS₄, Cu₃NbS₄ and Cu₃TaS₄ are calculated to investigate their electrical conductivity and electrochromic performance. They are potentially applied in solar cells and electrochromic devices as transparent semiconductors. Electronic structures indicate that the secompounds are indirect band-gap semiconductors, with conduction band minimum and valence band maximum located at X and R points, respectively, in Brillouin zone. Electronic states of conduction band minimum and valence band maximum are dominated by d-orbitals of Cu and Ⅴ-group elements, respectively. From band structure, atomic charge population analysis, electron localization function and optical adsorption/reflectivity spectrum it is suggested that these sulvanite compounds are polar covalent semiconductors with high charge transport mobility and extraordinary electrochromic characteristics. They could be applied to electrochromic devices.

With margins and their uncertainties, QMU (Quantification of Margin and Uncertainty) method can be used to make decisions on whether performances of a product reach demands or not. Recur to new methods of UQ (Uncertainty Quantification) for M&S (Modeling & Simulation), QMU is actualized with input information directly from M&S and its uncertainties. With reliability assessment for a stockpiled product, main ideas and executing details of QMU decision are demonstrated.

A 2D cell-centered multi-material arbitrary Lagrangian-Eulerian(MMALE) method based on moment of fluid(MOF) interface reconstruction is developed. Hydrodynamic equations are discretized and solved by cell-centered Lagrangian scheme. Tipton's pressure relaxation model is adopted as closure model for mixed cells. MOF method is simplified and improved to reconstruct interface in mixed cells. A conservative integral remapping algorithm based on cell-intersection is used in remapping phase. Several numerical examples are given, such as 2D periodic vortex problem, Sedov problem, interaction of a shock wave with an helium bubble,a strong water shock impacting on a cylindrical air bubble in water,2D Rayleigh-Taylor instability, etc.It shows that the method is of second order accurate, and is capable of computing problems involving large density and/or pressure ratios across interface. Its robustness is better than that of staggered MMALE method and it is applicable to complex multi-material hydrodynamic problems.

With ab initio theory and elastic scattering Green's function method, electronic structure, conductance and current of 1,4-phenylene diisocyanide molecule are investigated. It shows that charge of system is transferred and redistributed by electric field. Electron gathering area and dissipation area are formed near interface between molecule and electrodes. Additional electric dipoles are formed, which restrain conductance and current of molecule. Moreover, molecular orbit energy and coupling coefficients between molecule and electrodes are influenced obviously by electric field, which make differences in molecular voltage current characteristic.

Based on dynamic theory of liquid crystal and finite-difference iterative method, dynamic response of strong anchoring hybrid aligned nematic (HAN) liquid crystal cell as removing applied voltage was studied. Flexoelectricity of liquid crystal material was considered. Time-dependences of transmittance through a HAN cell were obtained. It indicates that response time decreases with increasing of absolute value of the sum of splay and bend flexoelectric coefficient |e₁₁+e₃₃|. Especially, at |e₁₁+e₃₃|=50 pC·m^-1 response time is half shortened relative to the case with no flexoelectric effect.

For efficient calculation of neutronic-thermal hydraulic coupling in pebble bed high temperature gas cooled reactor,a modified nodal expansion method (MNEM) was developed to solve convection-diffusion equation in cylindrical geometry.Within the framework of nodal expansion method,up to third-order polynomials combined with an orthogonalizd exponential function were adopted as basis functions for r-directed transverse integrated equation.Numerical tests reveal that the MNEM posses inherent upwind characteristic,and has good accuracy and stability for coarse meshes.

We present a second order cell-centered finite volume method of 2D Lagrangian hydrodynamics based on semi-discrete framework.Velocity and pressure on vertex of a cell are computed with characteristics theory,Then,they are used to compute numerical flux through cell interface by trapezoidal integration rule.With a reconstruction procedure,the method is extended to second order.Several numerical experiments confirm convergence and symmetry of the method.The method permits large CFL numbers and can be applied on structured and unstructured grids.It is robust in multi-material flow simulations.

Asymptotic waveform evaluation(AWE) technique in conjunction with equivalent dipole-moment(EDM) method is applied to obtain radar cross section(RCS) of an arbitrarily shaped three-dimensional(3-D) perfect electric conductor(PEC) over a frequency band.EDM method is used to achieve fast filling of impedance matrix and more derivative matrices.Inner and outer iterative near field preconditioning technique is used to solve matrix equation.Wide-band radar cross section is achieved by using AWE technique.Numerical results show that the computational efficiency is improved significantly with ensuring accuracy.

We present a cell-centered finite volume method for 2D invicsous Lagrangian hydrodynamics.Velocity and pressure on vertex of a cell are computed with characteristics theory,which is derived from governing equations of Lagrangian form linearized by freezing Jacobian matrices about a known reference state.The velocity is used to update coordinate of vertex of a cell.Product of two variables is used to compute numerical flux through cell interface by a trapezoidal integration rule.Convergency,symmetry and conservation of total energy of the method are demonstrated.The method can be applied to structured or unstructured grids,and does well spontaneously for multi-material flows in a robust way.The scheme is one order precision,and can be easily draw on two order precision.

Based on Ericksen-Leslie's elastic theory and dynamic theory, the responsive time parameter of the in-plane switching liquid crystal displays is analyzed, the chiral-planar alignment is introduced into this mode, and the dynamic equation of the director is given. The relation of the responding time and the twist angle is obtained by calculating the instantaneous distribution of the director in this mode. The computational result demonstrates that there is a short responding time in IPS-Chiral-Planar liquid crystal cell with a certain twist angle.

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.

A characteristic finite analytic method is proposed to obtain the numeri cal solution of convective diffusion eguation. The scheme formed is unconditionally L_∞ stable and in accordance with the convective diffusion phenomenon in physics.In this paper the existence and uniqueness of the scheme is proved and the error estimate of the numerical solution for the linear and non-linear equation is given. The numevical experiment shows that the present method has the ability to simulate the convective diffusion equation with high order accuracy, Irttle numerical dissipation, perfect stability and without any parasitic osillation.