Electronic structures and optical properties of ZnO, Bi-ZnO and 2Bi-ZnO are investigated with first-principles of plane wave ultra-soft pseudo-potential method based on density functional theory. It shows that variation trends of band gap of ZnO doped with different number of Bi atoms are not consistent. After doping, imaginary part of dielectric function peaks are broaden, and exhibit a red shift in the direction of low energy. Absorption peak, reflection peak and energy loss in high energy region decrease gradually as dopant atoms increased, which enhances transmission. Besides, absorption coefficient and reflection coefficient in visible and ultraviolet increase, which promotes the use of ZnO materials in visible light.

Structure, electronic and magnetic properties of (ZnSe)₁₂ clusters doped with one or two Mn atoms were studied with a first-principles method. Substitutional, exohedral, and endohedral doping are considered. Substitutional isomers are found most favorable for both monodoped and bidoped clusters. Magnetic moment is mainly contributed by 3d component of Mn atom, while 4s and 4p orbitals also have certain contributions. Due to hybridization interaction, a small magnetic moment is induced in nearest neighboring Se and Zn atoms. We demonstrate that endohedral bidoped (ZnTe)₁₂ clusters favor ferromagnetic state, which has potential applications in nanoscale quantum devices.

Structural and magnetic properties of (ZnO)₁₂ clusters doped with one (monodoped) and two (bidoped) Ni atoms were studied with a first-principles method. Substitutional, exohedral, and endohedral dopings are considered. Exohedral isomers are found the most favorable for both monodoped and bidoped clusters. Magnetic coupling between Ni atoms at the nearest neighbor position is mainly governed by competition between direct Ni-Ni antiferromagnetic interaction and ferromagnetic interaction between two Ni atoms via O atom due to strong p-d hybridization. Most importantly, exohedral and endohedral bidoped clusters favor ferromagnetic state, which has potential applications in nanoscale quantum devices.

Structural, electronic and magnetic properties of ZnS nanotubes (NTs) doped with Mn atoms are studied with first-principles calculations. Formation energies of doped NTs are smaller than that of the pristine, indicating that doing process is an exothermic reaction. Band gaps of doped NTs are narrower than that of the pristine. It indicates that Mn-doped ZnS NTs tends to adopt antiferromagnetic (AFM) configuration. To obtain room temperature ferromagnetism, we replaced a S atom by a C atom. Ferromagnetic (FM) states are lower in energy than AFM states by 0.454 eV. Such energy difference implies that room temperature ferromagnetism can be expected in the system.

Structures and magnetic properties of Cr monodoped and bidoped single-wall ZnS nanotubes are studied with firstprinciples calculations. Formation energies of doped nanotube are lower than those of pristine ones, indicating that doing process is an exothermic reaction. Doped nanotubes have atom-like magnetic moments mainly due to 3d component of Cr atoms. Our results indicate that Cr-doped ZnS nanotubes tends to adopt ferromagnetic (FM) configuration. Energy differences between FM and antiferrimagnetic (AFM) is only 36 meV. To obtain room temperature ferromagnetism, we replace one S atom by C atom. Its FM states are lower in energy than AFM states by 497 meV. Such large energy differences imply that room temperature ferromagnetism could be expected.

Magnetic properties of single-wall ZnS nanotubes (NTs) doped with Fe atoms are studied with first-principles calculations.Formation energies of doped NTs are smaller than that of pristine one,which indicating that doping is an exothermic reaction.Monodoped NTs has atom-like magnetic moments mainly due to 3d component of Fe atoms.It indicates that Fe-doped ZnS NTs tend to adopt antiferromagnetic (AFM) configurations.To obtain room temperature ferromagnetism,we replaced an S atom by a C atom and found that C atom prefers to substitute S atom connecting two Fe atoms.Ferromagnetic (FM) state energy is lower than that of AFM state by 164 meV.It implies that room temperature ferromagnetism is expected in these systems.

We study systematically structural and electronic properties of ZnO/ZnS superlattice nanowires and core-shell structural ZnO/ZnS nanowires with first-principles calculations. Relaxed structures of these heterostructural nanowires are found similar to those of homogeneous ZnO and ZnS nanowires. Band structures of heteronanowires show that they are direct-band gap semiconductors. For ZnO/ZnS superlattice nanowires, bands become flatter with the formation of minibands. For core-chell ZnO/ZnS nanowires, PDOS show that they are type-Ⅱ heterostructures. These may be important in understanding structural and electronic properties of heterostructural nanowires and their utilization in electric generator and photovoltaic devices.

Structure and magnetic properties of (ZnO)₁₂ clusters doped with one (monodoped) and two (bidoped) Co atoms are studied with first-principles method. Substitutional, exohedral, and endohedral doping are considered. Exohedral isomers are found the most favorable in both monodoped and bidoped clusters. Magnetic coupling between Co atoms is short-range. Magnetic coupling between Co atoms at the nearest neighbor is mainly governed by competition between direct Co-Co antiferromagnetic interaction and ferromagnetic interaction between two Co atoms via O atom due to strong p-d hybridization. We demonstrate that exohedral bidoped cluster favors ferromagnetic state, which has potential applications in nanoscale quantum devices.

Electronic and magnetic properties of ZnS nanotubes (NTs) were investigated systematically using first-principles approach. A double-wall NT (DWNT) with hexagonal cross section (HCS) shows higher stability, while zigzag and armchair NTs with round cross section (RCS) show lower stability than single-wall NT (SWNT) with HCS. Electronic band structures show that they are direct band gap semiconductors. With hydrogen adsorption, SWNT with HCS transform into indirect band gap semiconductor. Magnetic properties of ZnS NTs doped with transition-metal(TM) atoms (Cr, Mn, Fe, Co, and Ni) are calculated. Formation energies of doped NTs are smaller than those of the pristine ones, indicating that doing process is an exothermic reaction. All NTs have atom-like magnetic moments mainly due to 3d component of the TM atoms. Monodoped NTs have potential utility in materials with tunable magnetic properties.

Structure and stability of medium-sized (ZnS)_n (n=24,28,36,and 48) clusters are investigated by using first-principles approaches.A number of starting configurations for structural motifs were generated from handmade construction with chemical intuition and cut from bulk crystal.They are optimized via density functional theory(DFT).For medium-sized ZnS clusters,cage and tube structures were found the most preferred structural motifs.With increasing size,onion-like structures became more and more stable,which indicating that they are the lowest-energy structures for larger-sized clusters.Furthermore,it shows that WZ bulklike structures are more stable than ZB bulklike structures in medium-sized ZnS clusters.

With single-phase free surface Boltzmann method for flow field,free-surface condition and surface tension approach,we investigate process of two droplets impacting on a liquid film and two droplets with vertical interval successively impacting on a liquid film.Numerical result indicates that vertical distance between two droplets has influence on liquid film.Shape of liquid film changes greatly with intervals between droplets.Numerical result is in accordance with experiment qualitatively.

We propose a data reduction approach based on information theory. It comprises sampling of datssets based on mutual entropy and truncation based on offline Marginal Utility. The approach is a universal method for multi-dimensional scientific dataset streams. To show applicability, results obtained with plasma simulation data are presented, It reduces relationship and redundancy between datesets.

An implicit gridless method is investigated for the Euler equations. Clouds of points distributed all over the computational domain are adopted instead of common mesh generation. The spatial derivatives are directly approximated by using local least-square curve fits in each cloud of points. An upwind method using Roe's approximate Riemann solver is used for the estimation of the inviscid flux. The linear system of the resulting backward Euler temporal discretization is computed by using LU-SGS algorithm. The numerical implementations of the method are presented for transonic flows over 2-D airfoils, which reveals the flexibility of using clouds of points for complicated aerodynamic shapes.

An approach of exact controllability combined with non-overlapping domain decomposition associated to the physical layer structure of air and coated material media is presented for simulations of the scattering of planar waves in 2-D coated aerodynamic shapes.Domain decomposition with non-matching finite element meshes at the interface is introduced,which allows to use different numbers of grid points required by different media.The conditions of compatibility at the interfaces between each subdomain are satisfied weakly by a Lagrange multiplier technique.The whole structure of the algorithm includes one outer loop for capturing time periodic solutions based on exact controllability and one inner loop for domain decomposed solutions through a treatment of Lagrange multiplier.Numerical results of the scattered fields are presented and compared for both perfectly conducting and coated aerodynamic shapes like 2-D airfoils,which reveal the effect of the coated layer.

In the electromagnetic calorimeter,longitude light collection uniformity of crystal scintillator has certain influence on the energy resolution.Monte Carlo (MC) method (using Litrani software package) is used to simulate the process of light transmission and collection in the long lead tungstate (PbWO₄ or PWO) crystal.Discussion focused on the influence of the absorption length and the face management on the light collection is presented.And comparison between anisotropic simulation and isotropic simulation is made.

An exact controllability approach is used for the calcuation of time periodic solutions of the wave equation, which is proved to be equivalent to the Maxwell equation in two dimensions for the T.M.mode. The numerical results of scattered fields and Radar cross sections(RCS) are presented for complicated aerodynamic shapes with cavity, external obstacle or a slender body. The method presented has the ability to deal with more complicated aerodynamic shapes due to the use of unstructure triangulations.

The application of database technique for solving some problem in high energy physics analysis is discussed. By designing a connection program between the SQL language database and the software package PAW(Physics Analysis Workstation) commonly used in high energy physics analysis, the data processing capability, conveniency and practicability of PAW are greatly increased. This shows a new application field and prospect of databese technique in offline data physical analysis.

A penalty upwind finite element method is adopted to deal with the thermohaline double-diffusive system.The method has good stability and second-order accuracy. Natural convection with lateral heating in a square rectangular enclosure can be examined by this way, and it's solutions approximate to the results obtained with velocity-pressure Method. Afterwards, the method is employed for a two-dimensional, laminar, with lateral heating, steady double-diffusive convection partitioned by an adiabatic baffle. Main computation is for Ra=10⁶ and thermal buoyancy ratio N= 1,3,5,7. Distinct flow results depend on the magnitude of the thermal buoyancy ratio N and the baffle.

This paper presents a numerical study of the electric field distortion near the side frame of Proportional Inclined Ghanber (PIC) ,which is made of G10 epoxy resin plate, by using the finite element method. The calculation results are quite consistent with experimental tests. An optimized design scheme for improving the gain efficiency uniformity of the anode signal wires near the side frame is proposed.