Whereas under these conditions, these quantities, if you look at free energy change, for example at constant temperature and pressure, H you can still calculate H.

但是，在这些条件下，这些物理量，如果我们考察自由能的变化,例如在恒定的温度和压强下，我们仍然可以计算。

麻省理工公开课 - 热力学与动力学课程节选

It's a state function, so we're at constant temperature and pressure, and now we want to consider some chemical change or a phase transition or you name it.

这就是态函数，我们处于恒定的温度和压强之下，然后考虑某些化学变化或者相变,或者你想考虑的东西。

麻省理工公开课 - 热力学与动力学课程节选

But adding a constant velocity to objects does not change the fact that those which were maintaining constant velocity still maintain a constant velocity.

但是加上一个恒定速度并不会改变下述事实,即,那些正在匀速运动的物体,仍然保持匀速运动

耶鲁公开课 - 基础物理课程节选

So that should mean that the energy that's transferred to the electron should be greater, but that's not what you saw at all, and what you saw is that if you kept the frequency constant there was absolutely no change in the kinetic energy of the electrons, no matter how high up you had the intensity of the light go.

所以这意味着转移到电子,上的能量也越大，但这并不是，我们观测到的现象,我们所看到的是,如果固定光的频率不变,不管光强如何变化,电子的动能没有任何变化。

麻省理工公开课 - 化学原理课程节选

You just change volume to pressure and basically you're looking at enthalpy under a constant -- anything that's done at a constant volume path with energy, there's the same thing happening under constant pressure path for enthalpy.

可以看到这就是把体积换成了压强,一般我们都是在一种恒定状态下,考虑焓的，任何在恒容条件下,能伴随能量变化的东西，也在恒压条件下伴随焓同样地变化,所以你可以经常。

麻省理工公开课 - 热力学与动力学课程节选

How many moles of gas are there in each case, in reactants and products? If that changes, of course you know that the pressure in there is going to change at constant volume if the amount of gas in there is changing.

在反应物和生成物中，各有多少摩尔的气体？,如果它发生了变化,当然在等体条件下，如果气体的总量,发生了变化，压强也会发生变化。

麻省理工公开课 - 热力学与动力学课程节选

That was a constant enthalpy change.

这个过程是一个自由焓不变的过程。

麻省理工公开课 - 热力学与动力学课程节选

So now we have a constant volume reversible temperature change.

所以现在我们有一个,等体，可逆的温度变化。

麻省理工公开课 - 热力学与动力学课程节选

It only cares what temperature is. If temperature is constant, there's no change in energy.

如果温度是常数,能量就没有变化，对理想气体。

麻省理工公开课 - 热力学与动力学课程节选

So I need, well the pressure is constant, but there's a change in volume.

压强不变，体积变化。

麻省理工公开课 - 热力学与动力学课程节选

The ideal gas constant doesn't change, temperature doesn't change, and so v we just have minus nRT integral V1, V2, dV over V.

理想气体常数不变，温度也不变，因此,是负的nRT，积分从v1到v2，dv除以。

麻省理工公开课 - 热力学与动力学课程节选