In this class here, we're going to stick to one kind of work which is expansion work.

推动我的粉笔,我就对它做了功。

麻省理工公开课 - 热力学与动力学课程节选

So expansion work, for instance, or compression work, is if you have a piston with a gas in it. All right, you put a pressure on this piston here, and you compress the gas down. This is compression work.

力乘以距离，就是功，功有许多种：,电可以做功,驱动电机与电风扇,磁力也可以做功。

麻省理工公开课 - 热力学与动力学课程节选

Real refrigerators actually work with liquids that go into gases so use the latent heat of the liquid, so it doesn't really work like the Joule-Thomson expansion. So this is real.

液体变成气体来工作,以运用液体的潜热，所以这不是,真正像焦耳-汤姆逊膨胀一样工作,这是真实的气体，不像焦耳。

麻省理工公开课 - 热力学与动力学课程节选

Here there's an expansion going on, so the system is doing work to the external world.

这里发生了膨胀,所以系统对外界做功，活塞被推出来。

麻省理工公开课 - 热力学与动力学课程节选

It's an expansion, so we're doing work against the environment, or to the environment.

压强降低，系统对，外界做功。

麻省理工公开课 - 热力学与动力学课程节选

The work input during the expansion steps.

膨胀过程中的功。

麻省理工公开课 - 热力学与动力学课程节选