Г-半群中的粗理想

将粗糙集的理论方法用于Г-半群的研究，首先定义Г-半群上的同余关系，在此基础上给出Г-半群的粗糙子半群与粗糙理想等概念，并研究了它们的有关性质。     

Studies on nonlinear stability of three-dimensional H-type disturbance

The three-dimensional H-type nonlinear evolution process for the problem of boundary layer stability is studied by using a newly developed method called parabolic stability equations (PSE). The key initial conditions for sub-harmonic disturbances are obtained by means of the secondaryinstability theory. The initial solutions of two-dimensional harmonic waves are expressed in Landau expansions. The numerical techniques developed in this paper, including the higher order spectrum method and the more effective algebraic mapping for dealing with the problem of an infinite region, increase the numerical accuracy and the rate of convergence greatly. With the predictor-corrector approach in the marching procedure, the normalization, which is very important for PSE method, is satisfied and the stability of the numerical calculation can be assured. The effects of different pressure gradients, including the favorable and adverse pressure gradients of the basic flow, on the “H-type“ evolution are studied in detail. The results of the three-dimensional nonlinear “H-type“ evolution are given accurately and show good agreement with the data of the experiment and the results of the DNS from the curves of the amplitude variation, disturbance velocity profile and the evolution of velocity.     

双论域上粗糙近似算子的构造性方法与公理化方法

文献[1]在单论域U上，利用论域U上的二元关系，给出了粗糙集理论的构造性方法和公理化方法,本文将这两种方法推广到两个论域上的粗糙集,利用两个论域U和V之间的二元关系，研究双论域上粗糙集理论的构造性方法和公理化方法，推广了文献[1]的结论。     

Γ-半群中的粗理想

将粗糙集的理论方法用于Γ-半群的研究,首先定义Γ-半群上的同余关系,在此基础上给出Γ-半群的粗糙子半群与粗糙理想等概念,并研究了它们的有关性质.