positive displacement

基本解釋

Twin-screw pump as a positive displacement pump, pump room exhaust inhalation chamber should be strictly separated.
雙螺桿泵作為一種容積式泵，泵內(nèi)吸入室應(yīng)與排出室嚴(yán)密地隔開。
Refrigerating systems and heat pumps - Safety and environmental requirements - Positive displacement refrigerant compressors.
制冷設(shè)備和熱泵。安全和環(huán)境要求。容積式制冷劑壓縮機(jī)。
Double screw pump as a positive displacement pump, the pump suction chamber should be closely separated and discharge chamber inside.
雙螺桿泵作為一種容積式泵，泵內(nèi)吸入室應(yīng)與排出室嚴(yán)密地隔開。

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.
所以現(xiàn)在我們說,如果正電荷中心,就位于,那么還是在這里負(fù)電荷中心也在這里,所以沒有空間偶極。
麻省理工公開課 - 固態(tài)化學(xué)導(dǎo)論課程節(jié)選