At this temperature, the glass is a bright orange color.

VOA: special.2009.09.16

T2 So this is an isotherm at some different temperature T2, a cooler temperature, because this was an expansion.

这个绝热过程的温度是,比T1低，因为这是个膨胀过程。

麻省理工公开课 - 热力学与动力学课程节选

So this is going to end up at T2 a different temperature, we'll call it T2.

这个的末态有不同的温度,我们叫它。

麻省理工公开课 - 热力学与动力学课程节选

SdT This has minus T dS minus S dT, but the dT part is zero because we're at constant temperature.

这一项包含负的Tds和，但是dT的部分等于零,因为温度为常数。

麻省理工公开课 - 热力学与动力学课程节选

So at this point the temperature will change.

在这点温度会改变。

麻省理工公开课 - 热力学与动力学课程节选

Delta H of formation means the enthalpy of this compound minus the enthalpy of its constituent elements in their most stable state at room temperature and pressure.

生成焓就是这种组分,的焓减去它的所有组成元素,在室温和常压下处于,其最稳定的状态时的焓。

麻省理工公开课 - 热力学与动力学课程节选

So we're going to start at one, T1 and this is going to be in isotherm at temperature T1, and all the paths here are going to be reversible.

我们从一开始，这是个绝热恒温过程，温度是，所有路径都是可逆的。

麻省理工公开课 - 热力学与动力学课程节选

dG/dp And this is dG/dp at constant temperature.

这是恒定温度下的。

麻省理工公开课 - 热力学与动力学课程节选

We use a liquid helium. And so in order to make a liquid helium, you can't take helium at room temperature and do this, because if you did, you would just heat it up, because the room temperature is above the inversion temperature, so Joule-Thomson would heat up the helium.

为了得到液氦,不能再常温,做这个实验,否则就是加热氦气，因为室温高于它的转变温度,所以焦耳-汤姆孙，实验会加热氦气。

麻省理工公开课 - 热力学与动力学课程节选

This is going to end up at a different temperature by the way. You saw this last time in a slightly different way. Last time what you saw is we compared isothermal and adiabatic paths that ended up at the same final pressure, and what you saw is that therefore they ended up in different final volumes.

末态温度是不一样的,上次你们看到的,和这个有一点不一样,上次我们比较的是末态压强,相等的等温过程和绝热过程,因此它们的末态,体积是不一样的。

麻省理工公开课 - 热力学与动力学课程节选

In other words, the order of taking the derivatives with respect to pressure and temperature doesn't matter And what this will show is that dS/dp dS/dp at constant temperature, here we saw how entropy varies with volume, this is going to show us how it varies with pressure.

换句话说,对温度和压强的求导顺序无关紧要,结果会表明,恒定温度下的，对应我们上面看到的，熵如何随着体积变化，这个式子告诉我们，熵如何随着压强变化。

麻省理工公开课 - 热力学与动力学课程节选

And so the slope of this thing is f at the triple point, which is this point here, this is the temperature of the triple point of water, f divided by 273.16. That's the slope of that line.

除以x轴的坐标,这就是斜率，而直线,经过原点，因此斜率乘上T就得到。

麻省理工公开课 - 热力学与动力学课程节选