Based on the method of low pair replacing high pair, the problem of cam design was transferred to that of planar linkage design.

In the course of designing and manufacturing chemical equipments and pressure pipelines,we can not take it for granted that the replacement of materials is just the replacement of low quality materials by high quality materials,the replacement of inferior materials by superior materials and the replacement of thin materials by thick materials.

Research on arc block-roller type of lower pair overrunning clutch;

Unidirectional overrunning clutch with dual-wedge-block lower pair;

The traditional method of a higher pair replaced by lower pairs is proved to be able to guarantee the mechanism with higher pair and its equivalent lower pair mechanism have the same freedom,instantaneous velocity and instantaneous acceleration.

We extend the traditional method by replacing a low pair with a higher pair,and the use of the method can produce all possible structural types of a planar kinematic chain with multiple joints and higher pairs in accordance with the adjacent matrix of the kinematic chain of a planar link.

This paper presented a classification method to planar kinematic chains with multiple joints and higher pairs based on structural characteristics.

The traditional method of a higher pair replaced by lower pairs is proved to be able to guarantee the mechanism with higher pair and its equivalent lower pair mechanism have the same freedom,instantaneous velocity and instantaneous acceleration.

The main results are: (1) There are remarkable of interannual variation and with 3-years perodic variation of precipitation; (2) position of subtropical high are closely associated with interannual variatioll of precipitation during the second rainy season in south Guangxi; (3) E1 Nino and Southern Oscillation (EN.

Based on the daily mean and increment figures of atmospheric environmental monitoring data during 2000-2006,the subtropical high and the typhoon are analyzed,which are important synoptic patterns in summer and autumn,results show that the temporal and spatial evolutions of these systems have important influence on the envi.

It shows that the typhoon depression lasted for five days on land was because of a strong and wide convergence zone between two high pressures,together with the strengthening of southwesterly jet and its movement direction determined by the maximum wind speed by the subtropical high and the southwesterly.