All right, let's try again. How many people vote that this is reversible? That looks like a majority to me. Irreversible?
好的,让我们再试试,有多少人认为这是可逆的?,看上去大多数人都这么认为?
Of course in the reversible case, you're always pushing against an external pressure, which is essentially equal to the internal pressure.
当然在可逆的情况下,外压力,总是,等于内部压力。
Now,that thing that wakes up after this complete irreversible amnesia will no doubt eventually develop a personality,a set of beliefs,memories.
这人在经历了完全不可逆的失忆后醒来,最终发展出了自己的人格,信念和记忆。
It's been encrypted pretty naively, pretty simplistically, but it's actually an English sentence that's been somehow scrambled; but scrambled in a reversible way.
它被天真地,相当简单地加密了,但是它实际上是一个被加密的英语句子,但是加密方式是可逆的。
The other beauty about - beautiful thing about proteins is that if you make subtle conformational changes, often those changes are reversible.
蛋白质的另一个美妙之处就是,如果蛋白质发生一些小的构像改变,这些改变通常是可逆的
it becomes a gray area but it should be pretty clear if you can treat something is reversible are irreversible.
这是个灰色区域,但什么可以当作可逆过程处理,而什么要当作不可逆过程,这是相当清楚的。
Wrev w reversible. in this case here let's see this is it's a pressure is going down.
曲线下的面积,可逆过程的功,这个过程中。
Because it's so important. And I should add and also under reversible work, where the external pressure is equal to the internal pressure.
而且我还要说应该在外部压强,和内部压强相等的,可逆过程中引入它。
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。
So for the reversible process, the work done is the integral under the pressure volume state function, the function of state.
对可逆过程,做的功,是压强体积态函数曲线下,的积分面积。
get back to the initial point is going to require some input from outside, like heat or extra work or extra heat or something because you've done an irreversible process.
如果要逆转它,回到初始点,就需要外界的投入,比如额外的功,额外的热量等等,因为你进行了一个不可逆过程。
So what this says is the efficiency of any reversible engine T1 has to be one minus T2 over T1.
这就是说,任何可逆热机的效率都是,负T2除以。
OK, so now we're going to do the same kind of experiment, but irreversibly. An irreversible adiabatic.
现在来在,不可逆的条件下,完成相同的实验。
And I want to make sure everybody figured out that it really was an irreversible expansion.
或者多孔塞的,不可逆的等焓过程。
We can do it reversibly, or we can do it irreversibly.
它可以是可逆的,也可以是不可逆的。
that instead of all the steps being reversible, let's just put in one irreversible step.
不是所有的过程都是可逆的,其中有一个过程不可逆。
So w, the work is less for the irreversible process than the reversible process.
不可逆过程中系统对外界,做的功要比可逆过程时小。
All right, let's calculate the work that's involved with these two processes.
这些路径都是可逆的,可逆过程指的。
The reversible process is going to be colder because it has to expend more energy.
可逆过程降温更多,因为输出的能量更多。
And probably also in practice nothing is truly reversible.
或许在实践中,没有什么是真正可逆的。
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?
Every step won't be perfectly reversible.
每一步都不会是完全可逆的。
If it was non-reversible, I would be allowed to put an initial point and a final point, but I wouldn't be allowed to put a path between them like this, connecting them together.
如果是不可逆过程,我可以画出过程的初态点,和末态点,但是我不能再像这样,画出连接这两个点的,路径曲线来。
You've irreversibly changed that substance because you've changed the structure of all the proteins inside.
蛋白质的结构发生不可逆的变化,因为蛋白质内部的全部结构都改变了
No, pretty much things are either reversible or irreversible.
不,几乎所有的都是要么可逆,要么不可逆。
Like something is almost reversible and almost irreversible.
就像什么东西是几乎可逆的,或几乎不可逆的。
And again, I want to stress this is a reversible path.
再强调一次,我们研究的是可逆过程。
Now, you all know that we can make irreversible changes in proteins, you can denature them completely, that's what happens when you cook an egg for example.
现在你们都懂蛋白能够发生不可逆的改变,能够完全变性,比如在你煮鸡蛋的时候就是这样
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。
I mean we can, we can sort of understand why OK, the total energy, if we measure it, we measure a process which is not reversible.
例如我们易于理解为什么,当试图测量一个不可逆系统的总能量,给出的或许。
应用推荐