This paper develops a model for measuring air permeability of partially saturated asphalt samples using falling-pressure method in laboratory introduced by Li et al.

The natural precipitation method was performed for 10-minute exposure, and the impacting method was performed by FA-1 airborne bacteria sampler at flow rate of 28.

[Methods]Natural sedimentation method was used for the sampling according to the Hygienic Standard for Hospital Disinfection (GB 1598 2-1995) and the Technological Standard for Hospital Disinfection in 2002.

In order to know the status of bacterial contamination of air of clean operating room in the course of operation and its influencing factors,natural sedimentation method was used to sample the air of 10 clean operating rooms.

Methods To use the plat natural sedimentation method,collect the specimens of the air and count the germs at every 10min under the static state and working condition from BSC room pasteurized and purified and the fringe area of BSC pasteurized only.

Its operating principle lists as follows: first flushing fluid expelled from wellhead is decompressed throw sieve vessel,then sand,water and oil are separated by way of double natural sedimentation,finally,oil is recovered,water is recycled,and sa.