And it's more dramatic if the system is a gas p T2 V2 p, T2, V2, And let's look at what happens to U these functions of state, to H to u under this transformation.

如果是气体这个系统,就更具有趣了,让我们看看H和，在这个变化中态函数会发生什么变化。

麻省理工公开课 - 热力学与动力学课程节选

We discovered that the quantity dA, under conditions of constant volume and temperature, dA TS And A is u minus TS.

我们发现在恒定的体积和温度下，亥姆赫兹自由能的变化，小于零，is，less，than，zero。,亥姆赫兹自由能A等于内能u减去。

麻省理工公开课 - 热力学与动力学课程节选

Then that spread to the U.S. and people were very fearful, but the Fed, under Alan Greenspan, was very quick to respond and the whole thing didn't turn out to be anything so bad.

然后又蔓延到美国，人们都谈危色变，但政府在Alan，Greenspan引导下快速反映,事情才没有变的无比糟糕。

耶鲁公开课 - 金融市场课程节选

In some sense, that's one reason to associate this as a kind of energy, H just like mechanical energy u or enthalpy H, it's the minimum free energy state that is the equilibrium state under the relevant conditions.

在某种意义下，这是我们把这些物理量称为能量的原因，就像机械能U和自由焓，具有最小自由能的状态在特定的条件下,就是平衡态。

麻省理工公开课 - 热力学与动力学课程节选