The initial boundary value problem of wave equations and reaction-diffusion equations with several nonlinear source terms in a bounded domain is studied by potential well method. The invariance of some sets under the flow of these problems and the vacuum isolation of solutions are obtained by introducing a family of potential wells. Then the threshold result of global existence and nonexistence of solutions are given. Finally, the problem with critical initial conditions are discussed.

The effect of temperature on motion of misfit dislocation in the γ/γ' interface of a Ni-based superalloy is studied in periodic simulation cells subjected to an applied shear stress. The simulation results show that no matter what temperature is, the motion of misfit dislocation occurs through the nucleation and the propagation of the double kink; at low temperature, the interaction of the misfit dislocation facilitates the motion of the misfit dislocation; on the contrary, at higher temperature, it can obstruct the motion of the misfit dislocation, and improves the mechanical properties of nickel-base superalloys.

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