-
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。
-
And so an experiment said the gas didn't increase its temperature when it expanded the vacuum.
这个实验告诉你,气体在向真空膨胀的过程,中温度没有升高。
-
OK, you use the ideal gas law, etc., then you get a relationship that connects the pressure and the temperature, like here we got a relationship that connected the temperatures and the volumes together.
我们会得到，一个联系初末态,的压强和温度的，关系式,就像这个联系过程中。
-
Ideal gas only depends on the temperature, the energy only depends on the temperature.
只依赖于温度，因此等温过程中。
-
T2 Is the temperature T2 in this process smaller or larger than if I were to do the process reversibly with the same endpoint pressure.
这里的末态温度,与经过可逆绝热过程,到达相同压强的末态温度相比哪个比较高呢？
-
Constant temperature means isothermal, so this part means an isothermal process.
等温“指温度不变，这部分就是指一个等温过程。
-
If I'm working under conditions of constant temperature and volume, that's very useful.
如果在恒定的温度和体积下,进行一个过程，这是非常方便的。
-
You're running, you're shaking a beaker up here at room temperature.
你跑步，震动烧杯，这都是在恒定温度和压强的情况下的过程。
-
What happened to the temperature in a Joule expansion in ideal gas?
对理想气体,焦耳-汤姆逊膨胀过程中温度如何变化？
-
We know in an adiabatic expansion the system's going to cool.
我们知道在绝热膨胀过程中,系统温度会降低。
-
But now, so this is where the refrigeration comes in. So if you take a gas, and you're below the inversion temperature and you make it go through this irreversible process, the gas comes out colder from that side than that side.
这就是冰箱的原理,如果在低于转变温度,的情况下我们将气体经过,这个不可逆过程,气体出来的温度将比这边低。
-
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。
-
The purpose here is to look at a series of processes in which temperature is held constant, and we're going to calculate how much work we get from allowing a gas to expand under various conditions.
目的是让大家了解一下,几个保持温度不变的过程，然后我们将计算,气体在不同膨胀过程中,的对外做功。
-
If I look at different points in my container during that path, I'm going to have to use a different value of pressure or different value of temperature That's not an equilibrium state, and that process turns out then to be an irreversible process.
如果我要研究在路径中容器里的,不同的点，我就得在容器里不同的点上使用,不同的压强值,或不同的温度值,实际上这不是个平衡态，这个过程是,不可逆过程。
-
So this isn't the most useful form that we can have, but what we'll see shortly is that from this, we can then derive further criteria for essentially any set of variables or any set of external constraints, like constant temperature or pressure or volume and so forth that we might set.
所以这不是我们所能得到的最有用的形式，但是我们会很快看到，我们能够进一步推导出包含任意变量,或者任意约束的自发过程判断标准，比如说恒定的温度，压强,体积或者其他我们能够给出的约束。
-
All right, so gamma, the gas is cooling so V2 is going to be less than it what would be if the temperature kept constant.
气体温度下降了,于是V2会比等温过程,降到相同压强时的体积要小。
-
Let's say we start from some V1 and p1 here, so high pressure, small volume and we end up with a high volume low pressure, under constant temperature condition.
例如我们要从压强比较高，体积比较小V1，p1出发,到达低压强，大体积的末态，过程中温度不变。
-
Last time we reach the third law which is telling us that we can't quite get to zero degrees Kelvin .but that as the temperature approaches zero degrees Kelvin, the absolute entropy of a pure substance in perfect crystalline form is zero.
上次课我们得到了热力学第三定律,这个定律告诉我们我们无法,达到0K的温度,但是在我们接近绝对零度的过程中，以完美晶体形式存在的纯物质的绝对熵,也趋向于零。
应用推荐