The regularity of forming secondary branch on the primary branch of female plant was studied by using three sterile lines with different percentage of sterile plant and crossed with same male parent.

4%Mg alloys on the mor-phology of dendrite α phase was investigated and the amount of dendrite αphase and the characteristic parameters, the primary dendrite spacing and secondary dendrite arm spacing, were also measured.

The characteristic parameters of dendritic α phase in near-eutectic Al-Si alloys modified with varying strontium, primary dendrite spacing and secondary dendrite arm spacing, were measured and the changes of the mechanical properties with these parameters were considered.

In this paper, Melnikov's method is used to discuss a dass of equation governed by flickering on catalytic wires(gauzes) and in chemical reactor, the conditions of the existence of subharmonic bifurcation are obtained.

By using Melnikov s method,the conditions of the existence of chaos,subharmonic bifurcations and super-subharmonic bifurcations are obtained.

In this paper,the authours have proved the existence of chaotic behaviour andsubharmonic bifurcation in the periodic time-dependent Kolmogorov system with constant harvest-ing rates by using Melnikov s method.

The regularity of forming secondary branch on the primary branch of female plant was studied by using three sterile lines with different percentage of sterile plant and crossed with same male parent.