"I was appalled. When you read through it it's sort of like it's a memo out of some science fiction movie - I mean, the temperature of the air can't be any lower than thus and so, you can't do it for any few minutes.
VOA: standard.2009.04.17
You measure your temperature is a little up, you've got a fever, something's wrong, I better find out what that is' because temperature is a very highly controlled variable.
你测出体温偏高是,你就发烧了,身体哪里出问题了,我最好把问题找出来,因为体温是一个严格控制的身体指标
And the path that I'm describing then, let's assume that we're raising the temperature up is this path right here.
经过一个,等压过程,路径就是这样。
Some of the challenges that you see here I mentioned before, so there are problems with drought, with pests, with temperature changes and the like.
我之前提到的,你们所见的这些挑战,如干旱问题,虫害问题以及温度变化之类的
If I then put it back into its original condition, lower the heat say, temperature back to body temperature and reduce the pH down to seven again, the molecules will re-nature.
假如我把烧杯的温度恢复到初始状态,降低温度,温度降低到体温,将pH值降低到七,这些分子会复性
Yet, the temperature goes up. So, I can have a temperature change which is an adiabatic temperature change.
它与外界不会,有物质或者能量的流动,然而系统的温度升高了。
Now, we saw before, or really I should say we accepted before, that for an ideal gas, u was a function of temperature only.
我们已经看到,或者说我们已经接受这样一个事实,即理想气体的内能只和温度有关。
In other words, now I know how to tell how the Helmholtz free energy changes as a function of temperature.
换句话说,我现在知道如何写出亥姆赫兹,自由能作为温度的函数。
And then maybe I raise the temperature to whatever, room temperature, maybe 20 degrees hotter than room temperature. And I again say OK, now how much heat do I need to raise this thing's temperature by 1 degree?
我可能把温度升到,比如室温,或者比室温高20度之类,然后我再说,好,现在要把这个东西的温度,升高一度需要多少热量?
So I've got, this piston here is compressed, and I slowly, slowly increase the volume, drop the temperature.
这样,这个活塞就被压缩了,然后我再很慢很慢地增加它的体积,降低温度。
So, all I want to do now is look at the derivatives of the free energies with respect to temperature and volume and pressure.
我现在所要做的一切就是,考察自由能对,温度,体积和压强的偏导数。
I want to cool a gas with a Joule-Thomson experiment, what temperature do I have to be at?
给气体降温时,需要到达什么温度?
Now, if I want to change those quantities; change the temperature, change the volume, how will it change?
如果我现在打算改变这些量;,改变温度,改变体积,它会如何改变?
Now, I know how to relate the heat flow to temperature change, through the heat capacity.
现在我知道怎样把能量的流动,和温度的变化联系起来,通过热容。
So again with the Gibbs free energy, now I see how to determine, if I change the pressure, if I change the temperature by some modest amount, how much is the Gibbs free energy going to change?
再一次通过吉布斯自由能,我知道当我,适当的改变压强和,温度的时候,吉布斯自由能如何变化?
Now to make that happen, it's not adiabatic, right. If I wanted to do that, I'd need a heating element or something to cool, so I could make that temperature change happen, right.
要实现这点,它就不会是绝热的,对吧,如果我想做到这点,我需要一个加热元件或什么制冷的东西,这样我才能让温度变化。
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?
Similarly for G as a function of temperature and pressure, I can go through the same procedure.
同样的G作为,温度和压强的函数,我可以采用相同的步骤。
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。
I suppose we could specify the surroundings temperature.
假定我们能够,确定环境的温度。
So I just got to get rid of the temperature now.
现在我们。
I won't end up at the same temperature.
但不结束在相同的温度。
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 I'll start at some initial temperature, T1.
那么我从某个初始温度T1开始。
If there's no heat flow between the b and c, then I can say all right, a and c were the same temperature.
如果在与之间没有热量流动,那么我就可以说,好吧与处于相同的温度。
You need a substance and then that substance has to have a property that changes depending on the heat flow, i.e., depending on whether it's sensing that it's the same temperature or different temperature than something else.
你需要某种物质,它的某种性质,随着热量的流动而改变,也就是说,依赖于它是否感觉到它,与其他的物体处于相同的温度。
Path number 3 is a constant temperature path, and I already wrote the answer.
它是一个等温过程,我已经写出了答案。
Somehow I've gotta get rid of the temperature and make it pressure instead.
应当用压强,来消去温度。
I want to measure the temperature.
我想要测量温度。
I change the temperature, what does that mean?
只改变温度,偏H偏p是多少?
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