And then by using the perturbation method and the variational method,the general expression of the critical load change relative to different pile-soil system parameters in the initial-post buckling process is deducted,and effects of these parameters on the initial-post buckling behaviors of the piles are discussed.

In this paper,a new architecture of small windpower generating system,which features simple structure,low cost and high reliability,is introduced and the disturbance injection method of maximum power control is given.

In the control of the disturbance injection method used to resolve wind turbines in less than rated speed’s control.

Then,by using the principle of minimum potential energy and perturbation approach,the unified variation expression of critical load during initial post-buckling is deduced with.

5-D FEM is used for calculating Fréchet derivatives in the crosshole resistivity image and three kinds of calculating techniques, namely, standard method, Green function method and perturbation approach are presented respectively.

Reconstruction of tissue diffusion optical tomography using perturbation method;

The ocean wave model constructs ocean surface mesh by sine wave and realizes the bumping effect of ocean surface through normal disturbance of bump map method.