Lattice parameters, atom positions and electronic structure of Pu-based superconductor PuCoGa₅ are studied with local spin density approximation (LSDA) and LSDA+U method of full potential linear augmented plane wave (FLAPW) method based on density functional theory. LSDA+U formalism was used to account for the strong on-site Coulomb repulsion among localized Pu 5f and Co 3d electrons. It shows that results of LSDA+U considering strong correlation between Pu and Co agrees well with relevant theoretical and experimental data, especially, PuCoGa₅ Pu-5f strong domain features of electronic spin down. In addition, orbital hybridization between Pu-5f and Co-3d is obviously stronger than that of Ga-4p.

Structures,stabilities,and magnetic properties of Pt_n(n=1-9) are calculated with generalized gradient approximation functional BPW91 and three-parameter hybrid density functional B3LYP in density functional theory.The methods give same stable structures and same lowest-energy structures but different stable order of sub-stable structures.Average coordination numbers and average bond lengths in two methods have similar patterns.They increase with cluster size,and have a great increase at n=2-3 and a small increase at n=4-9.Analysis of energies by two methods show that there are greater values at n=2,5,8,which illustrate that corresponding clusters have high stabilities.Study of Pt clusters indicates that average magnetic moment oscillates with cluster size.It has a gradually decrease trend.It shows that two methods can describe structures,stabilities and magnetism of clusters.

Based on the observational data of comet Hale Bopp's spiral jet structure obtained in Shanghai Astronomical Observatory from March to May 1997,the formation of the spiral jet structure is simulated by using Monte Carlo method.A basic model is proposed and the effect of different parameters is discussed.The numerical results reproduce the observed jet morphology Satisfactorily.

In the paper, an improvement λ-type scheme is proposed based on characteristics idea in order to overcome the strong dispersive effect or nonlinear instability of the original λ-scheme. Furthermore, the numerical simulations of two models of ID computational fluid dynamics problems by using the improvement scheme are given, and the numerical results are satisfactory.

In this paper, we study the analysis solution for the problem of rectangular oil and gas reservoir with boundaries of different types. We can estimate the boundaries location of reservoir by using the methods of numerical simulation and optimization.