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Thermodynamics is asking you, what work does this thing do on the surroundings or the surroundings do on the system?
热力学在问你们，到底是系统对环境做功,还是环境对系统做功？
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No, we call that work positive work. All right, so that means we need to put a negative sign right here, by convention.
历史上有过不同的习惯，这里我们规定,如果环境对系统做功。
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The respiratory system, for example, the renal system, the digestive system, these are examples - three examples of organ systems that contact the external environment.
例如,呼吸系统,泌尿系统,消化系统,这些系统,这三个系统,与外环境相联系
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The problems are complex because we're trying to make a system in which people are able to make their own decisions as much as possible and to make them in a way that--in an environment that they trust.
问题总是复杂的,我们试图创造一个,人人都可在其中,尽情决策的系统,创建一个,人人彼此信任的环境
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It's just minus the sum of all these things, because of course these are just defined as the work done by the environment to the system.
等于负的这些东西的和，因为它们的定义是,环境对系统所做的功。
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So we have system insulated from the outside world, and we have two bulbs.
我们有一个与环境隔绝的系统，和两个腔体。
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It either had work, got its heat from the surroundings, or it got worked on by the surroundings.
系统从环境中，得到热量。
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Then, after you define what your system is, whatever is left over of the universe is the surroundings.
当你定义了你的系统后，宇宙的其余部分,就是环境。
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And there is no work done on the surroundings because pressure is zero.
这里系统没有对环境做功,因为压强是零。
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If we say we have a system, and it's in its surroundings.
如果我们有一个系统，它在环境中。
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We've talked about the interesting way in which the digestive system contacts the external environment.
我们会讲到,消化系统与外环境之间十分有趣的联系
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So, the system does work on the surroundings, hence the minus sign.
系统对环境做功，因此符号是负的。
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Well the system got its work from the surroundings.
环境对系统做功。
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And then between the system and the surroundings is the boundary.
系统和环境之间的,是边界。
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It also turns out that they're made stable in these environments like milk and mucus secretions because of this secretory chain which is wrapped around it.
同时,连接抗体还可以,使抗体在像乳汁或是粘液分泌物,这样的体内环境中保持稳定,因为分泌循环系统可以将抗体包裹在内
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So, if I'm the system, then everything else is the surroundings.
因此，如果我是个系统，那么其他任何事物都是环境。
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w we have the environment doing work on the system OK, now we've assumed that epsilon prime is greater than epsilon.
大于零，that，is，in，this，one,在这里环境对系统做功,好，现在我们假设,ε’比ε大。
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There's no change in them, and then we also looked at some at non-state functions, work and heat, and saw that those aren't zero going around a cycle. Of course you can do work in a cyclic process, and heat can be exchanged with the environment at the same time.
它们不会有变化，然后我们研究了,一些非态函数，功和热量，并看到,沿着循环行进一周的话,它们并不是零，当然你可以在,一个循环过程中做功，而同时热量可以在系统,与外界环境之间进行交换。
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This is providing work that's being used in here, but if you take the whole outside of the surroundings and this whole thing is the system, no net work, these things cancel each other, and yet heat's going up.
如果把外面的全部当成环境，把这里的全部当成系统,那么就没有净的功，它们相互抵消了，热量向上传输，会发生什么？
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Depending on what you call external and internal environment, this path that I'm tracing here, deep within your digestive system, is really directly connected to the outside world through both ends.
基于你们所谓的外环境和内环境,我在这里我所指的消化系统内部通路,它的两端确实与外界环境直接相通
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Anybody have an idea? What's the one function of state? I'm the system, the rest are the surrounding. What's the one function of state that's constant when I'm doing all my chemical reactions to move my arms around?
态函数又是什么呢？,我是一个系统，其余的是周围的环境,那么当我在做所有的化学反应,去四处移动我的手臂的时候,什么量是常数？
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Adiabatic means that there's no heat transferred between the system and the surrounding.
绝热是指没有热量,在系统和环境间传递。
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And here, in an isothermal expansion, The bath is putting back the energy that the gas is expanding or using to expand, and so the energy is flowing back into the gas through the environment in the isothermal expansion.
而在等温膨胀中，恒温环境将气体膨胀对外做功,而损失的能量又返还回来，在等温膨胀中,能量从环境,流向系统。
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And so, we can immediately write this du and then we can write du for the universe, which is system plus surroundings is equal to zero.
因此，我们可以立刻写出这个等式,然后可以写出总的的，也就是系统加环境的du，等于零。
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U It's u, because u is to q plus w right, heat and work, but it's adiabatic. So there's no heat, exchange with the environment, and it's constant volume, so there's no p dV work, right.
什么是零？是U，因为,等于q加w，热量和功，但这是绝热的，所以系统与环境间没有热量交换；,同时它是灯体的，所以也没有pdV形式的功。
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