在恒定温度下它就等于体积。

At constant temperature. It's just the volume.

youdao

即恒定体积，改变温度，这里恒定温度下。

Then we can take the derivative of that quantity, when we vary the temperature, holding the volume constant.

youdao

这里有一点变化，即恒定温度下的。 。

We would have a point, say, down here at five and seven.

youdao

To ask questions like how much heat is released in a chemical reaction that takes place at constant temperature.

当我们想要知道,当一个化学反应在恒定的温度下发生时,会放出多少热量时。

麻省理工公开课 - 热力学与动力学课程节选

Whereas under these conditions, these quantities, if you look at free energy change, for example at constant temperature and pressure, H you can still calculate H.

但是，在这些条件下，这些物理量，如果我们考察自由能的变化,例如在恒定的温度和压强下，我们仍然可以计算。

麻省理工公开课 - 热力学与动力学课程节选

And in particular let's look at, for example, du/dV du/dV at constant temperature.

更特殊一点考察，恒定温度下的。

麻省理工公开课 - 热力学与动力学课程节选