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Based on the statistical model for the tensile statistical strength of unidirectional composite materials, a new method is proposed to calculate the tensile statistical strength of the 3-D braided composites. The numerical result shows that the tensile statistical strength of 3-D braided composites can be predicted according to this method.

Through analysis of buckling and stress for a composite cylindrical shell, such technique targets as critical load, strength and stress distribution of 3D-braided composite cylindrical shells are calculated numerically. These results indicate that the effect of buckling to the 3D-braided composite CNGV is indubitable. Based on the 4-step 3-D circular braiding procedure and the theoretical analysis mentioned above, a mathematic model about the structural optimum design of 3D-braided CNGV is proposed. According to this model, the calculated example shows better effects.

The catalytic system of (2-(2-benzimidazolyl)-6-((1-aryliminoethyl)pyridyl))nickel chloride/MAO (methylalu- minoxane) was found to be good active for vinyl polymerization of norbornene and provided polymers with relative narrow molecular distributions. Various reaction parameters, such as the ratios of nickel precursor to MAO or monomer norbornene, and the nature of the ligands in complexes were carefully investigated to realize their effects on the catalytic activities, polymer molecular weight and molecular weight distributions.