We looked at pressure change before, actually, in discussing the third law, the fact that the entropy goes to zero as the absolute temperature goes to zero for a pure,perfect crystal.

在讨论热力学第三定律的时候，我们讨论过压强变化,即对于纯净的完美晶体,随着温度下降到绝对零度熵也变成零。

麻省理工公开课 - 热力学与动力学课程节选

And our other reference point is the triple point of water - reference points become zero Kelvin, absolute zero, and the triple point.

而使用绝对零度,它与压强无关,是最低的温度，另一个参考点是水的三相点。

麻省理工公开课 - 热力学与动力学课程节选

Last time we reach the third law which is telling us that we can't quite get to zero degrees Kelvin .but that as the temperature approaches zero degrees Kelvin, the absolute entropy of a pure substance in perfect crystalline form is zero.

上次课我们得到了热力学第三定律,这个定律告诉我们我们无法,达到0K的温度,但是在我们接近绝对零度的过程中，以完美晶体形式存在的纯物质的绝对熵,也趋向于零。

麻省理工公开课 - 热力学与动力学课程节选