positive displacement

基本解释

Twin-screw pump as a positive displacement pump, pump room exhaust inhalation chamber should be strictly separated.
双螺杆泵作为一种容积式泵，泵内吸入室应与排出室严密地隔开。
Refrigerating systems and heat pumps - Safety and environmental requirements - Positive displacement refrigerant compressors.
制冷设备和热泵。安全和环境要求。容积式制冷剂压缩机。
Double screw pump as a positive displacement pump, the pump suction chamber should be closely separated and discharge chamber inside.
双螺杆泵作为一种容积式泵，泵内吸入室应与排出室严密地隔开。

So now that means if this is where the center of positive excess charge lies and on top of it is the center there is no displacement of the charge so there is no net dipole.
所以现在我们说,如果正电荷中心,就位于,那么还是在这里负电荷中心也在这里,所以没有空间偶极。
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