Through expounding the filtering function of the high efficiency filter on gem and virus and the principle of no leakage return air installation,proves that when the high efficiency filter is fitted in return intakes,the partial circulation air conditioning system can be used in isolation ward.

Study on the leaking risk of rocket kerosene stored on launching site based on fuzzy theory

The structure defect of automatically controlled vertical self-suction pump was analysised,which is commonly used in market,and the self-suction theory,structure and design of vertiacl self-suction pump with upright suction and no leakage was introduced.