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In this study, a new plane magnetic abrasive finishing method by using alternating magnetic field has been proposed to solve the problems such as the easy deformation and poorly restored of the magnetic brush in traditional magnetic abrasive finishing. Compared with the magnetic brush in traditional magnetic abrasive finishing, the magnetic brush can keep a relatively stable shape to finish the workpiece under the action of alternating magnetic field. In this paper, the variation of the finishing force in the alternating magnetic field is analyzed theoretically. In addition, in order to get the ultra-precision plane surface, the influence of the size of the magnetic particles, the size of the GC particles, and the frequency of the AC power on the finishing characteristics has been studied. The best experimental results show that the surface roughness of the workpiece is improved from 38 nm Ra to 6.33 nm Ra.

The vibration of the fifth frame mill of 1450 Cold Tandem Rolling Mill in the rolling process was studied using finite element software ANSYS. The dynamic analysis of one-piece frame and two-piece frame on the fifth frame mill were carried on. The natural frequency and mode of vibration were calculated. Through analyzing, we obtained that two-piece frame performed better.

Electro-geometric (EGM) model is now the most popular method for the shielding failure flash-over rate (SFFOR) calculation. In this paper, the Lightning protection theory of the negative angle protective pin is studied on basis of this method, and Installing the negative angle protective pin on the hillside or the peak of the 35kV transmission line in order to reduce the ground shielding failure which is the main cause of lightning flash-over of 35kV transmission lines in DeXing Copper Mine in Jiangxi Province. It was suggested that this research must be considered as one of the important factor in the lightening protection of transmission lines.