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。

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.

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如果我们测量热力学量会发现自由焓的变化,等于4千焦，正4千焦。，delta，H，is，4，kiloJoules，，plus，4，kiloJoules。,熵增dS是45焦耳每开尔文。

If we measure the thermodynamics, we discover that dH Delta S is 45 joules per Kelvin.

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通过追踪该比率随时间的变化，他可以确定氡气到达地表需要花费多长时间，同时获得气体所通过的岩石的化学、热力学和机械状态。

By tracking this ratio over time, he can determine how long gas has taken to reach the surface and gain clues to the chemical, thermal, and mechanical state of the rocks the gas is passing through.

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So now let's go around the cycle and just compare notes on what happens to the thermodynamic quantities as we do that.

现在让我们推导一下这个循环,比较一下这个过程中,热力学性质的变化。

麻省理工公开课 - 热力学与动力学课程节选

And if you work out the energetics as we've gone with thermochemistry, dH you discover there's a huge negative delta H.

如果你计算能量变化,就像在化学热力学中所作的一样，你会发现很大的负的。

麻省理工公开课 - 热力学与动力学课程节选

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