Based on the hydrodynamic theories,makes an overall analysis on composing of the resistance loss in ammonia pump suction side,puts forward one calculation method of ammonia pump head which is accord with actual requirement of project,and analyzes how to avoid cavitation of ammonia pump from the aspect of design and actual operation.

In our country s civil action, the identification standard of introducing the high probability has already had its rational foundations, there are its important meanings.

The author concludes that we should set up the criteria of "high probability" in legislation and carry out the necessary reform in the existing system.

The law of China applys different distribution rules for burden of proof such as inversion of the proof responsibility,high probability,bewisvereitelung to assure an objective and fair adjudication in the impairment compensation.