complete air changes 全室换气次数
air changes per hour 每小时换气次数 ; 每小时换气量
number of natural air changes 自然换气次数
fresh air changes 新风换气次数
The air temperature changes 气温变化大
Everything changes the air bubbles 一切都变气泡了
air r changes 换气次数
The existing standard for LABS at UBC is 10 air changes per hour.
UBC实验室目前的标准是每小时换气10次。
There shall be 10 air changes per hour of ventilation in wet laboratories and 8 air changes per hour of ventilation in dry laboratories.
化学实验室空气换风量至少为10次每小时，仪器室至少为8次每小时。
To get a feel for what this would mean, bear in mind that the amount of oxygen in a given volume of air changes with atmospheric pressure, and the local pressure changes with the weather.
要了解这将意味着什么？给定体积的空气中的含氧量是随着大气压变化而变化的，而当地的气压又是随天气变化的。
And although U.S.officials say small adjustments may be possible in the specific plan for an air base in northern Okinawa, Secretary Gates said he doubts the U.S.Congress would agree to significant changes in the agreement, particularly if they would cost the United States more money.
VOA: standard.2009.10.20
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