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So now we have a relationship between the ratios of these volumes that are reached during these adiabatic paths.
现在我们有了一个联系,这些绝热过程中,体积比的关系式。
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Adiabatic can be either reversible or not, and we're going to do that probably next time or two times.
绝热过程可以是可逆的，也可以不是，我们可能会在下一次或下下次课上,研究这个问题。
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You're allowed Cv comes out here for this adiabatic expansion, which is not a constant volume only because this is always true for an ideal gas.
绝热过程写下,这个式子是因为它对理想气体都成立，并没有用到等容过程的条件,只用了理想气体的条件。
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Be careful. Suppose we are doing an adiabatic process.
假设我们在研究绝热过程。
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As long as it's reversible, you know what the efficiency has to be, and in principle, you could break it down into a bunch of steps that you could formulate as isothermal and adiabatic.
只要这个循环过程是可逆的，你们知道效率是多少，从理论上说，可以将总过程,分解成一系列绝热,和等温的小过程。
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So there's going to be a line that's going to connect the initial point to the final point, and that line mathematically is not going to be the same as this one here.
连接绝热过程,初末态的曲线的方程，和等温线的方程,也不会相同。
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dq=0 But if it's adiabatic, then dq is equal zero, du=dw and for an adiabatic process, then du is equal to dw.
但如果它是绝热的，那么，因此对于绝热过程。
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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。
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Okay two going to three that's this, it's adiabatic, right.
从二点到三点，是绝热过程。
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Now,this is a reversible adiabatic path, so there's a relationship that I'm sure you'll remember.
现在是可逆绝热过程，因此这里有一个关系式,我相信你们还记得。
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We've changed the external pressure slowly, and again this is isothermal.
我们慢慢改变外部压强，这个过程也是绝热的。
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Then we're going to have another isothermal step, a compression to some point four.
然后有另外一个绝热过程，绝热压缩到4点。
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u=0 And it's approximately equal to zero for all real gas processes.
在所有理想气体绝热过程中Δ,对真实气体近似为零。
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So your time scale it just fast enough that this is basically an adiabatic compassion.
你的时间足够快以至于,基本上是一个绝热过程。
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We're pretty much done with our definitions STUDENT: Was adiabatic reversible?
各种定义,学生：绝热过程是可逆的吗？
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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？
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And now we're going to have another adiabatic step, an adiabatic compression.
现在我们进行另外一步，绝热收缩过程。
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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。
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Well, all right, delta u is equal to zero for that.
好吧，绝热过程中。
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We could do an adiabatic process.
我们再来研究绝热过程。
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And you know, you could have a reversible engine with lots and lots of steps, but you could always break them down into some sequence of adiabatic and isothermal steps.
你们知道，我们可以设计一个由，很多很多个,循环步骤的热机，但是总可以把它分割成,一系列的绝热,和等温过程。
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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。
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We're going to close the cycle with another adiabatic step.
换一个,绝热过程。
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Then we're going to have an adiabatic expansion.
然后一个绝热膨胀过程。
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These are all constant. It's isothermal.
它们都是常数，这个过程是绝热的。
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This is an adiabatic process.
这是一个绝热过程。
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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。
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Adiabatic q equal to zero. It's also delta H 0 which is zero. The two didn't necessarily follow because remember, delta H is dq so p is only true for a reversible constant pressure process.
在这个过程中ΔH等于,绝热的所以q等于0，而ΔH也等于,这两个也不一定有因果关系,因为，记住，ΔH等于dq只有在恒压。
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