The seepage mechanics model comprises multiple nonlinearly coupled partial differential equations. In various applications, seepage mechanics problems exhibit distinct characteristics and the corresponding solution methods are also very different. This paper focuses on the representative mathematical models used in oil and gas reservoir development. It introduces the mathematical formulation and application characteristics of multiphase multicomponent seepage mechanics equations within porous media, along with efficient techniques for solving their discretized linear equation systems, including commonly employed preconditioning methods. Additionally, this study appropriately modifies standard test cases and evaluates the shared-memory parallel efficiency of these preconditioning methods.

A multi-heat source ring-shaped heat-supply network is not a plane net and supply-return pipe net is dissymmetric under faulty condition. We present a method for topology structure of spatial heat-supply network based on graph theory. With object-oriented programming,it defines graph and includes correlation arithmetic according to basic structure information of supply-return pipe net and builds incidence matrix and fundamental circuit matrix automatically. It creates a spatial heat-supply network "tree"which includes information of heat source and heat users and adopts breadth-first search based on plane graph. According the tree,basic incidence matrix and fundamental circuit matrix of spatial heat-supply network are established. In simulating heating network of Harbin development zone,a program of multi-heat source ring-shaped heat-supply network in topology structure is build and computing performance is verified. It provides a method for complex heat-supply network hydrodynamic condition analysis and dissymmetric heatsupply network calculation based on arithmetic of graph and adapts to various model pipe nets.

An improved sliced sensitivity reconstruction algorithm is proposed for three-dimensional(3D) magnetic resonance electrical impedance tomography(MREIT).Using single component of magnetic flux density measured by a MR scanner,all slices are reconstructed respectively with a modification for 3D conductivity images.Simulation of a cubic model shows that the proposed algorithm improves interlayer crosstalk phenomenon with a higher image resolution than sliced reconstruction without modification and entire reconstruction algorithm.Computing time is significantly reduced.Simulation on a human leg model shows feasibility for complex imaging objects.Phantom results verify reconstruction algorithm in real measurements.The improved sliced sensitivity reconstruction algorithm reduces requirements for computer capability and reconstruction time of 3D MREIT with high imaging precision and efficiency.

We develop a modified Youngs interface reconstruction algorithm for Eulerian muhi-material hydrodynamic numerical methods. In the algorithm, the material's volume fractions of surrounding cells are used not only to calculate position of the interface but also to determine the transportation priority of materials. In a two dimensional muhi-material Eulerian hydrocode MMIC-2D, the algorithm is employed and validated in simulation of a cirque moving in a translational flow field in two dimensional Descartes coordinates. In the simulation of jet formation of shaped charge, material interfaces are clearly shown and agree well with experimental resuhs. It demonstrates accuracy and efficiency of the modified Youngs interface reconstruction algorithm.

A relaxation algorithm is developed to simulate sphere packing with arbitrary diameter distribution.An adaptive iteration period is employed to keep the packing density stable with various number of spheres.The packing density and the coordinate number of the algorithm are higher than those of previous approaches.The efficiency of contact detection is considerably increased by background grids and double link group structure.The time complexity of the algorithm is O(N),where N is the number of spheres.It needs only CPU time of 217s to achieve a packing density of 0.64 for random close packing of 10 000 equal spheres with an AMD Athlon 3200+PC.New classification of numerical methods for sphere packing is also presented.

The basic functions in the method of moment (MoM) for 2D electromagnetic (EM) scattering problems that is symmetric about X-axis and Y-axis are obtained with the represention theory of finite group.We construct the group and get its regular representations.The tentative functions according to the four center symmetric positions are shown.While the regular representation is transformed into an irreducible one,orthonormal basic functions composed of the tentative functions are obtained.

The intrinsic frequency of molecular-vibration of nonmetal binary hydrides is calculated with mechanic vibration theory.Both the fundamental frequency (ω₀) and the summed frequency (Σω_i) are used as molecular structural indices,and the established model:pK_a=A₀+A₁ω₀+A₂Σω_i is applied in the quantitative relation analysis.It is shown that the estimated correlation coefficient between pK_a values and the indices in the data set is larger than 0.995.Comparing the period values with the experimental values of pK_a,the mean absolute error is estimated to be less than 1.82.

Grand canonical Monte Carlo (GCMC) method is adopted to investigate the dependence of hydrogen storage capacity on the diameter of a single-walled carbon nanotube (SWCNT), the distance between walls and the shell number of a multi-walled carbon nanotube (MWCNT),as well as the inter-tube distance and configuration of SWCNT array (SWCNTA),at 298K and 10MPa.The calculated results show that when the diameter of SWCNT approaches 6 nm the average number density (n_AV) of hydrogen within the tube reaches its maximum.When the difference between the internal radius and the external radius increases from 0.34 to 0.61 or 0.88 nm the hydrogen storage capacity is improved effectively.As the inter-tube distance of SWCNTA approaches 1.7 nm n_AV within the interstitial space of SWCNTA reaches its maximum and a square array is better than a triangular array for hydrogen physisorption.It is also found that n_AV within the interstitial space is larger than that within the tube whether for a square array or a triangular array,only if inter-tube distance is larger than 0.6 nm.The hydrogen storage capacity could be effciently increased by the reasonable choice of the diameter of SWCNT,the distance between walls of MWCNT,the inter-tube distance and configuration of SWCNTA.Conclusions are discussed and explained.

The capability of hydrogen storage in zigzag single-walled carbon nanotubes is investigated.Relations of diameter and length with the hydrogen reserves and the distribution of hydrogen storage in single-walled carbon nanotubes are obtained.A new expression of hydrogen storage capability is presented.

Integral equation method is one of effective methods of numerical simulation and inversion calculation for multi-dimensional electromagnetic response.Based on the linearization of the scattering electromagnetic integral equation, conductance imaging using iterative Born approximation is effective.Aiming at the characteristics that iterative Born approximation inversion depends on the initial model and that QL approximation doesn't need initial value, the two step method,iterative QL-Born approximation method,is put forward,which takes the result of QL inversion as the initial model of the iterative Born approximation method and avoids contrived initialization.The iterative QL-Born approximation method is effective and testified by numerical experiments

An analytic modified embedded-atom model is presented.Using the model,the thermodynamic data,such as the dilute-limit heats of solution,formation enthalpies of disordered solid solutions,surface energies and surface segregation energies for Pd-Au alloy,are calculated.The results are in agreement with the experimental data and calculated data using ab initio theory.

Considering the robustness and commonness, it uses the evolutionary algorithm to calculate the characteristic of H^- and He in outfield.The calculation for ground state energy of H^- and He can be converted to a problem of function optimization.At first the MCI method is adopted to deal with state wave functions of H^- and He, then the evolutionary algorithm calculates their ground state energies.Results show that it can obtain much more accurate results, and compared with other algorithms, it's more efficient.

It assesses the Rayleigh inverse-iteration method and boundary layer asymptotic expansion method, and uses them into the stability equations of compressible boundary layer and the numerical method for forecasting the transition point. It gives also a stability analysis on the first mode of the boundary layer of flat plane and a forecasting of transition point. Results are discussed and compared with observations.

Effects of condguration mixing and relativistic corrections on the dielectronic satellite spectra have been studied for the He-like ions with low-and medium-Z. The atomic Parameters characterizing the dielectronic satellite lines are evaluated by using the send-and non-relativistic Hartree-Fock models. The results calculated show that (1) configuration mixing has an important effect on the dielectronic satellite spectra for the He-like ions, and (2) for the medium-Z He like ions, it is no longer sufficient that the effects of relativity are considered in the form of perturbation energy corrections, and in order to obtain more accurutc numerical results, relativistic corrections should be made both for energy and for radial wavefunction.