Currently the popular method firstly to be used is the geometry guided diffusion equation which is based on the Cartesian coordinate system, for the isophote(the curve of constant value of image graylevel) being evolved, then the Open-Close operation can be being.

Based on a 3-DOF dynamic seat,conducted the kinematics analysis of the two DOF mechanism of the back pad unit,by introducing the geometric constraint equations of the mechanism,the stiffness in the constraint direction was considered as infinite,then built the stiffness equation based on the virtual work principle,finally analyzed the stiffness characteristic based o.

On the basis of the hypothesis of straight normal line, geometrical equations about finlte deformation analysis of shells with small shear are exactly derived by means of continuum mechanics methods.

The paper deduced geometric equation based on the physical concept of engineering linear and shear strain and the characteristics of "axial symmetry" and "large deformation".