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

即恒定体积，改变温度，这里恒定温度下。

麻省理工公开课 - 热力学与动力学课程节选

And then we can take the derivative with respect to temperature, it's just R over molar volume minus b.

这样我们求,压强对温度的偏导数，结果等于R除以摩尔体积V杠减去b的差。

麻省理工公开课 - 热力学与动力学课程节选

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