The purpose here is to look at a series of processes in which temperature is held constant, and we're going to calculate how much work we get from allowing a gas to expand under various conditions.

目的是让大家了解一下,几个保持温度不变的过程，然后我们将计算,气体在不同膨胀过程中,的对外做功。

麻省理工公开课 - 热力学与动力学课程节选

Maybe you don't control thermostats in your dorm room, some of you do and some of you don't probably, and maybe it doesn't work very well so it might not be a good example, but imagine a perfect thermostat that you set for a temperature and then the temperature stays the same inside the room no matter what the temperature is outside.

可能你根本就不理卧室里的恒温器,有些人去调它,有些人就置之不理,可能它压根就是坏的,所以这个例子也许并不恰当,但你还是想象一个完美运行的恒温器,你设定温度后房间里的温度就保持不变,不管外面温度是多少

耶鲁公开课 - 生物医学工程探索课程节选

du/dT constant pressure is the direct derivative with respect to temperature here, which is sitting by itself under constant volume keeping this constant but there is temperature sitting right here too.

偏U偏T，p恒定是对,温度的直接微分，而它本身对体积不变,保持它不变，但是这里也有一个温度,这就是偏U偏V，T恒定。

麻省理工公开课 - 热力学与动力学课程节选