In addition to pumping air and no condensate and other non-corrosive gases, widely used in pumping speed and the need for high vacuum of truth in this system.
适用于抽除空气及其它无可凝性及无腐蚀性的气体，广泛应用于需要大抽速和高真空的各种真这系统中。
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In particular, we have found that even at the mean field level the naive vacuum saturation approximation is not a good approximation when we consider nonlocal four quark condensate.
In this paper, the influences of these factors on the optimum vacuum are analyzed firstly, and the calculation method of condensate subcooling degree and the dissolved oxygen in condensate are given.