We investigate numerically topological Chern number in a two-dimensional triangular-lattice with three bands, considering tight-binding Hamiltonian. Energy spectrum is obtained with Fourier transform and Hall conductance is calculated using Kubo formula. It is found that Chern number of energy band is modulated by next nearest neighbor hopping integral t'.Three bands own Chern numbers in sequence, {-4, 5,-1} at t'=1/2, {2,-4, 2} at t'=-1/2 and {2,-1,-1} at t'=±1/4, which leads to Hall plateaus in sequence, {-4, 1}e²/h, {2,-2}e²/h and {2, 1}e²/h, respectively. Peaks of density of states (DOS) are located at jumps of Hall conductance. Energy gap (DOS=0) gives width of corresponding Hall plateau. If energy band becomes more flat, corresponding peak of DOS becomes higher and sharper, and jump of Hall conductance becomes steeper.

Based on a microscope capillary model,a mathematical model for induced polarization of reservoir rock is obtained.Influences of concentration difference polarization and electric double-layer deformation on induced polarizability are studied numerically.It shows that induced polarization is governed by ion concentration difference polarization in capillary.Electric double-layer deformation has greater influence on total polarizability.Speed of charging and discharging in induced polarization depends mainly on cation exchange capacity and pore structure of rock.

A difference scheme for diffusion equation on Voronoi meshes is constructed using finite volume method.The diffusion discretization scheme is simpler on Voronoi meshes than on quadrilateral meshes.It introduce no cell-node unknown and improves accuracy of the discrete calculation of cell-edge flux as well as accuracy of difference scheme.The diffusion calculation on Voronoi meshes can be coupled with cell-centered hydrodynamics calculations.Computation examples demonstrate that the accuracy on Voronoi meshes is higher than that on quadrilateral meshes and Voronoi meshes adapt well to distortion.

A jet symplectic algorithm for Euler-Lagrange systems is studied.It is shown that the discrete Euler-Lagrange (DEL) equation,which was given by the second author in 1998,has fundamental geometric structures that preserve along solutions obtained directly from the variatonal principle.It is shown that these difference schemes are jet symplectic and the Nother's theorem exists by which we give the definition of a discrete version,the momentum map.A numerical example in jet symplectic difference scheme is given.A comparison with other discretization schemes was made.

A method preserving structures of the Hamiltonian systems is considered. On the basis of the jet symplectic difference scheme for canonical Hamiltonians the jet symplectic difference scheme for Hamiltonian systems in general symplectic structure with variable coefficientsic is defined. According to the general approach of the generating function method for the symplectic difference schemes a relation between the general symplectic structure and the generating functions is found. The jet symplectic difference schemes for classical Hamiltonian systems are constructed in terms of Hamilton-Jacobi equation.

On the basis of the G-P algorithm it proposes an optimal algorithm for computing simultaneously the correlation dimension and the Kolmogorov entropy from time series.The correlation dimension obtained from this method is optimal and the stable estimation of the Kolmogorov entropy is also obtained.The applicability of the method is illustrated with two examples,viz.,the Lorenz attractor and Rossler attractor.

In this paper, the effects of the fitting parameter △E₀ on the structural determinations in the EXAFS structural study of amorphous alloys have been discussed through the model calculations. The results show that the cancellation of the fitting parameter △E₀ can increase the reliability of the data analysis in the EXAFS structural study of amorphous alloys.