instability criterion
1.Instability condition is expressed by dJ_app/da≥dJmat/da The proposed instability criterion agyees with the results of the actual test.
2.Sixth, the mechanism of drift instability based on the physical interpretation of GKS stability criterion is remarked.
3.The plasmon dispersion and Charge-Density Wave(CDW)instability for electron superlattice are also studied. The criterion of the unstable region of CDW is obtained.
4.The superplastic deformation process is davided into four stages,namely, stable, quasistable, strain path drift to plane strain and plane strainstages, and a damage-instability model duriug superplastic deformation of shcetmetals is developed through numerical method. On the basis of the above results and taking the occurrence of localized instability (dε2=0) or the cavity volume fraction reaching the critical value(fc)as a fracture criterion, the forming limitduring superplastic deformation of sheet metals is predicted.
5.In this paper, a simple measure for eliminating the drift instability of the multi-transmitting formula in numerical simulation of wave motion is first presented based on a physical interpretation of GKS stability criterion in the numerical solutions of initial-boundary value problems of the hyperbolic partial differential equation. Validity of the suggested measure is then tested by numerical experiments for a three dimensional wave source problem and a three dimensional scattering problem.
6.1. Starting from a two-layer nonlinear quasi-geostrophic baroclinic vorticity equation containing Ekman friction, a new generalized energy is proposed to act as Lyapunov function and thus a new criterion of nonlinear baroclinic subcritical instability containing two inequalities is obtained.
7.? In the light of ?R?i<f/ζ?a? , the criterion of instability for inertial gravitational wave as put forward by Hoskins, and considering the feature of moist barolinic atmosphere, we analyzed a rainfall event occurring in the East of China at 02BLT, 29 June, 1996. The following conclusions are obtained: the SW lower level jet was a main medium of moisture needed for the formation of rainfall event;
