Using the central field approximation theory and the configuration interaction method, the electronic wave function, orbital energy, radius, total binding energy of atomic Ce are calculated.

The section error,the relative error between the biggest shearing stress of accurate stress field and the biggest one of approximate stress field around the peak of Ⅰ- Ⅱ compound crackles,has been analysed,which provides the theoretical evidence for photoelasticity to measure KⅠ and KⅡ s error.

The orbital stability in the central force field;

The orbit of motion in central force field is discussed and a few decision methods of the orbit stability are given.

By the natural and harmonious relationship between differential forms and differential equations and between differential forms and vector analysis, we discuss the properties, which are covariant under the transformation of coordinates in the framework of differential forms, of particle motion in a central force field.

In addition,we discussed the character of these curves and the relations between Multi-knot curve and central field.

In this paper it is shown that there are two vector constants of the motion for a charged particle in the central field of force.

In this paper,the symmetries of two central fields in the classical mechanics that result in closed orbits for all bound particles are discussed by using the group theory method.