若在适当端口施加正弦电压源，则网络的稳定性取决于进入端口基波电流的实功与虚功成份的符号值。

When exciting Sin voltage source is applied to proper port, the stability of network depends on the sign of active and reactive components for fundamental-wave current entering port of networks.

youdao

So the force that you're pushing down on here is the external pressure times the area.

或者压缩功的概念,在活塞上施加压力。

麻省理工公开课 - 热力学与动力学课程节选

So you know, what the second law is doing, in other words, it's putting these restrictions on how well or how effectively we can convert heat into work in the case of the engine, or work into heat extracted in the case of a refrigerator.

你们知道，在热机中，热力学第二定律的作用，换句话说，就是给热量,转化为功的效率,施加限制,或在制冷剂中，对抽取热量,进行限制。

麻省理工公开课 - 热力学与动力学课程节选