Based on the analysis of the charge pump,methods of optimization for the operation frequency and switch\'s size are proposed,as a result of which,the DC-DC conversion efficiency and power efficiency are improved.

To analyze the influence of the distribution of jet fans on the pressure-rise coefficient in curvy tunnel with small radius and find the optimal distribution of the jet fans,the CFD method was carried out to simulate and analyze the jet characteristics for some cases of various distributions of jet fans.

In order to put forward technical research and exploitation for drilling hole hydraulic mining, the technological process, ejection mechanism, squirt gun design, lift up efficiency and security stabilization of it are synthetically analyzed, meanwhile many technical problems are reduced to five different outlines.

The optimum analyses of the raising condition and the raising efficiency are made by means of theoretical analyses of basic equations in the process of raising liquid in the paper.

This research analyzes the efficiency promotion of urban housing in vestmentsand harmony analysis based upon empirical studies on 20 domestic residetai.