It even results in geologic hazard;for the mine geologic hazard,the background of physiognomy is the potential factor,while the irrational exploitation is the magistral factor.
Development trend of domestic third-stage multiclone is expounded as well as the problems such as single tube wearing, low capacity of single tube and the inappropriate catalyst exhaustion.
For the reason why optical activity of mesomer is counteracted classical answer was not convincing. By use of the helix theory and stable staggered conformation answer can be obtained.