OK, but in order to relate turning these physical knob to this quantity here, which we don't have a very good feel for, we've got to have a feel for the slopes.

热量是怎么进一步改变的,但是为了把这些物量同我们，不是很理解的焓联系起来，我们对微分已经有了一定的了解。

麻省理工公开课 - 热力学与动力学课程节选