You're always wasting energy into heat somewhere when you dochange that involves mechanical change.

当进行与机械运动有关的变化时,总会有能量变成热量而被浪费掉。

麻省理工公开课 - 热力学与动力学课程节选

So, I need to tell you how you're doing the expansion, because that's going to tell you how much energy you're wasting during that expansion.

所以我需要告诉你,膨胀是如何进行的，因为这会告诉你,在这次膨胀中,浪费了多少能量。

麻省理工公开课 - 热力学与动力学课程节选