It's related to the heat capacity, the constant volume of heat capacity and something you could measure.

它联系了热能，恒容热容和一些,我们能够测量的物理量。

麻省理工公开课 - 热力学与动力学课程节选

Now, you know with constant volume, H now it's not going to be delta H that's U straightforward to measure, it's going to be dealt u, all right.

好，现在你们知道在体积恒定的条件下，我们得到的不是Δ,我们直接测量到的是Δ,好，但这基本上也是一样的。

麻省理工公开课 - 热力学与动力学课程节选

So, you do this measurement, you measure with the gas, you measure the pressure and the molar volume.

现在让压强趋于，现在测量气体的压强，和摩尔体积。

麻省理工公开课 - 热力学与动力学课程节选

Now these quantities were useful because you could relate them. The slope of changes, with respect to volume or temperature of the energy with respect to quantities that you understood, that you could measure.

去得到这些量,这些量很有用，而且你们已经知道了，怎么把它们相互联系起来,像这种比例形式的量，能量比上温度或体,或其它你们懂的可以测量量。

麻省理工公开课 - 热力学与动力学课程节选

Now let's change the pressure and temperature and sweep through a whole range of pressures and temperatures and measure the volume in every one of them.

然后改变气压和温度,并且让气压和温度,取便所有可能的数值,测量相应的体积。

麻省理工公开课 - 热力学与动力学课程节选

But because in many cases we can reasonably either model or measure equations of state, collect data for a material for its temperature, pressure, volume relations, then in fact if we can relate all these quantities to those then in fact we really can calculate essentially all of the thermodynamics. For the material.

但是因为在很多情况下,我们能够合理的给出状态方程的模型,或者通过收集一个物质的，温度，压强和体积之间的关系,来测量其状态方程，所以实际上我们可以给出压强等物理量,和热力学势之间的关系,并计算出所有的热力学势，对于给定的物质。

麻省理工公开课 - 热力学与动力学课程节选

We can measure the heat capacity at constant volume, and now we have another term, and if we can figure out how to measure it, we'll have a complete form for this differential du which will enable us to calculate du for any process.

我们能够测量恒定体积下的热容，这里我们有另一项，如果能够知道怎么测量它，问我们就有了这个完整的微分式,就能够对任何过程计算。

麻省理工公开课 - 热力学与动力学课程节选