Fractal approach is introduced. Mathematical model of fractal triple medium fissure cave reservoir with low velocity non-Darcy effect is established. By means of Laplace transform and Stehfest numerical algorithm, bottom hole pressure solution is obtained. Seepage characteristics analysis and nonlinear parameter sensitivity analysis are conducted. Finally, combined with actual well data fractal model is verified. It shows that seepage process of fractal triple medium fissure cave reservoir can be divided into 6 seepage stages. They are presence of wellbore storage, transition flow, channeling of caves to fractures, pseudo radial flow, channeling of matrix to fractures and caves, total radial flow, respectively. Furthermore, effect of velocity non-Darcy effect on percolation law is gradually increasing with time. The higher starting pressure gradient, the higher pressure dynamic curves in total radial flow stage bend upward. Fractal coefficient affects whole percolation process. With increase of fractal coefficient, fracture tortuosity and flow resistance increase and whole pressure dynamic curves move up.

Geometrical structures of Cr doped and Cu-Cr co-doped 32-atoms supercell of AlN were optimized with first principles density functional based on full potential augumented plane waves and generalized gradient approximation (GGA). Lattice constant, band structure, electronic density and optical properties were calculated. It indicates that Cr-doped and Cu-Cr co-doped AlN are both half metallic, their band gaps become narrower. Cu-Cr co-doped AlN system has stronger spin polarization effect than Cr doped, and exhibits fine ferromagnetic. Range of optical absorption becomes broader with doping. Co-doping enhances long-wave absorption and energy loss decreases obviously.

With asymptotic assumption for physical field near notch tip, characteristic differential equations for electroelastic singularities of wedges that contain bounded piezo/piezo materials are built from three-dimensional equilibrium equations and Maxell equations. Mechanical and electric boundary conditions are expressed by combination of singularity orders and characteristic angle functions. Thus, evaluation of singularity orders is transformed into solving ordinary differential equations (ODEs) under designated boundary conditions. Interpolating matrix method is introduced to solve derivative ODEs. More electroelastic singularity orders and associated eigenfunctions in wedges that comprise two bounded transverse isotropic piezoelectrics materials are obtained. It shows that the method is efficient and has high accuracy compared with existent solutions.

A visco-elasticity polymer flooding mathematical model with three phases and five components is established with mass conservation principle.IMPES method is used to simulate the polymer flooding considering tackffying effect of elasticity,action of decreasing residual oil and visco-elasticity of heavy crude.It indicates that visco-elasticity polymer flooding decreases saturation of residual oil and increases viscosity of flooding system effectively,and then enhances oil recovery.As polymer concentration increases, oil recovery rises qucikly,and then tends stable.An optimal value is about 2 000mg·L^-1.As injection rate grows.oil recovery increases and then declines.There exists an optimum value.Oil recovery increases rapidly with the increasing of injection volume,and then tends stable.The best volume is 0.6PV.

A local convergence condition of Newton-Laphson's method in solving diseretization nonlinear equation8 of coupled problems is shown and proved.It gives out relation among time-step and space.step and quasi.compres8ion factor. And it provides theoretically an assurance for convergence of Newton.Laphson's method within numerical analysis. Numerical example shows that the time-step in actual calculating can be greater than theoretical value 5lightly.

Monte Carlo method is used to simulate ions in a double-layer target of Ti film on Al substrate.As high-intensity pulsed ion beam (HIPIB) irradiates on target,deposited energy results in rapid increase of surface temperature.Meanwhile high energy ions make cross mixing among atoms at film and substrate interface.Shooting ions and energy deposition influence melting or vaporization of target materials.It changes adhesion between film and substrate.It shows that cascade collision mixing is not a main process in mixing of a double-layer target by HIPIB irradiation.The most preferable ion current densities lie in a range of 100 A·cm^-2~150A·cm^-2.

Space-time conservation element and solution element(CE/SE) method with second order accuracy is modified on hexahedral grids. High-order accuracy in space and time is obtained by expanding variables in SEs with high order.CE/SE method is used to capture shock waves in chemical reaction flows,elastic-plastic flows and unsteady multi-phase incompressible flows.Numerical results are compared with experimental and theoretical results of classical examples.It is indicated that the method is easy to implement, accurate and efficient.Application of high order CE/SE method is extended.

We extend the CE/SE scheme and present a complete Eulerian approach for two-dimensional(plane strain and axisymmetry) elastic-plastic flows with solid features.Eulerian governing equations are adopted and solved on a fixed Cartesian grid.Johnson-Cook constituted equations and Mie-Grüneisen equation of state are used to describe materials.A hybrid particle level set method is used to trace interfaces of materials.Two types of boundary condition are presented in tracking interface.The penetration of a steel target by a WHA long rod is simulated and the computational results are carefully compared with those in other literatures.

A new treatment of pressure boundary condition for DSMC method is proposed.With the new method,the computational divergence of traditional "number flux method" can be avoided and a higher convergence speed than the "averaged at inlet" method is obtained.The flows in micro-channels driven by different pressure drops are investigated using the new method.Comparison between DSMC results and continuum-based results has also been made.

Building on direct numerical calculation, it analyzes the dynamics of atoms propagating through a laser standing wave (SW) potential in the regime of immersion-lens.The spot size of Cr atomic deposition is estimated. It is also shown that some physical quantities, such as atomic velocity distribution, laser detuning and laser beam radius, play important roles in determining the quality of atom lithography.

The flow characteristics of various flaps with slots is studied by solving the Reynolds averaged Navier-Stokes equations with two-layer zonal model,while the pressure distribution is measured by experiments.The results reveal that the flow structure of flaps with slots depends on the interaction of flows around two parts of the flaps with slots.The two flows have no intervention at porosity η=50%;but they interact stronly at η=20%,30%.The circulation zone downstream of the flaps becomes larger and has weaker turbulent intensity.

A general Monte Carlo program has been developed to study the performance of the X-ray intensifying screens and imaging systems.The program contains three major parts, each of which describes one of the interaction steps occuring in the system:the absorption and scattering of X-rays, the diffusion of generated electrons, and the diffusion of light photons.Through comprehensive verification, it shows that the simulation methods for all physical processes are correct and the results obtained are credible.For a kind of Gd₂O₂S:Tb intensifying screen, several characteristic parameters such as the number of collected light photons, light collection efficiency and PSF depending on the incident X-ray energy are calculated.These basic physical quantities are useful for the prediction of the information transfer properties of a phosphor layer.

The occasional coupling synchronization scheme of the active-passive decomposition (active-occasional coupling) is proposed,which consists of both synchronization and autonomous phases.In the former,the synchronization scheme is used to synchronize the drive and the response system;in the latter,small errors will lead to the separation and desynchronization of the two systems. If the synchronization phases are sufficient enough,the full synchronization will occur.The synchronization condition is discussed in theory,and the relation between the synchronization phases and the coupling strength is also investigated numerically.