Deducing error equation that used vector rotating and transfer of axes theory,Measuring out measurement parameter error on different orthogonality by testing optical-electrical device.

In the paper,the rotation vector of a spin vector is introduced,and the rotation vectors of spin vectors of T,N and B are characterized.

By virtue of some known results of the existence on at most one or two limit cycles of the Lienard systems,using the theory of rotated vector field,we study the number and relative positions of the limit cycles of the n-demensional differential system =y,=-(hxn-1+δ)y-(xn-x)(h>0),where n is a positive integer greater than 1.

Moreover, the generalized rotated vector field, constructed in the present paper, is used for obtaining the existence condition of period solutions for another system.

In this paper by means of three types of exampls,we investigate the distinction problem of what types of bounded separatrix cycles the limit cycle of quadratic system will become,when it is extending in rotated vector field as the parameter varies monotonically in a suitable direction.

By application of the theory of rotating vector field ,this paper obtains the sufficient conditions for limit circle of the second system of Ⅲ a=0 x=-y+x+lx 2+mxy+ny 2(n=-1,0<l<1) y=x(1+y), that exists in origin periphery.