It is proposed for the first time that the so called rotational structure system played an extremely important role in copper and tin mineralization in the area and it controlled the distribution and occurrence of strata,dykes,structures and veins.

The present paper deals with stratigraphy,structural assemblage and their spatial distribution and third-level tectonic element consisting of multi-level composite folds and related boundary faults characteristic of brush structural system in the north Qiangtang Basin by the example of Dogai Coring region.

Based on analysising the force of a spring before loaded in rotating system,the authors analyzed the force of the spring after loaded in rotating system and suggested a concept of sign angular.

In this article,the authors analyze the stress of spring without load in rotating system and test the conclusions with experiments.