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Somebody say it real loud. Yes, the system is working on the surroundings, right? It's pushing out against them.
有人很大声的回答了，对，系统在对外做功，他把外界向外推开。
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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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We'll get into the proper or at least more systematic business of the course when we turn to hermeneutics next week.
下周我们讲到阐释学的时候,将会真正地或者说更系统地对这门课程进行讲解。
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We would think that Milton's contemporaries might be aghast that such a sympathetic portrait of Satan could be used at the beginning of the poem.
我们很可能以为，与弥尔顿同时代的人,看到本诗开头就对撒旦有如此具体系统的描述,定会感到惊骇。
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Well, one reason is that there are developmental disorders that seem to involve damage to one system but not to another.
一个原因是,发展障碍看上去,只会对某一个系统产生损害,而不会损害其他系统
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One is because we understand the bone marrow system so much better than we understand all the other stem cell systems.
一个原因就是我们对骨髓系统的认识,远高于其他干细胞系统
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And so, you know from your Newtonian mechanics, as you were learning in 8.01, the dynamic force here mv^2/r is mv squared over r.
在8。01节对牛顿动力学系统的学习中，我们可以知道这里的运动受力,就是。
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The gold standard was a success in the sense that the price of gold stayed constant because that's what the whole system was designed to do.
金本位制度是一个成功,因为金子的价值保持不变，并且这也是,人们当初对这设计整个系统的意图所在。
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The immune system is stronger, so it also helps in terms of physical health.
免疫系统更强，所以对身体健康也有帮助。
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That creates all sorts of social consequences that we'll talk about sustainability, with shipping water long distances, all the plastic involved, people's distrust of public water systems that's unfounded, and things like that are very interesting and have big public health consequences.
这就产生了很多社会问题,比如我们将要谈到的饮水污染问题,饮用水在长途运输的过程中,会受到各种塑料污染,还有人们对公用自来水系统,毫无理由地不信任,类似这些现象都很有趣,而且会导致重大的公共健康后果
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So, and of course, you know, keeping entropy as a fixed variable for a system like that is extremely cumbersome.
所以，对这样的系统要求它们的熵保持恒定,和一个非常笨拙做法。
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OK, so w, first of all, work is being done to the system on the left hand side here.
好的，首先,我们通过左边对系统做功。
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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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f truth is the recognition of the systematic character of a certain kind of error, then it would be fully dependent on the prior existence of this error.
如果真理是,对一种错误的系统化字符的认可，那么它会完全依赖于这个错误的先前存在。
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That's achieved - in fact that's the main goal of many of these organ systems, right?
这通过,事实上这是,很多器官和系统存在的主要目的,对吧
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This will lead us into a discussion of sort of bioengineering of the immune system, in particular, and we're going to talk next week about vaccines.
我们会借此展开对,免疫系统的生物医学工程化的讨论,下周我们将讲到疫苗
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It's not going to be zero this time because we have non zero heat exchange between the system and the environment, right.?
热力学量，但是现在让我们看一下,我们的特殊函数，这次它不会是零,因为系统与外界的热量交换并不是零，对吧？
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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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Wirr Minus w irreversible, this is the work which is done to the environment by the system, -Wrev minus w irreversible is always smaller than minus w reversible.
一点提示，不可逆过程中系统,对外界做的功，总是小于,之前我们。
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Change in entropy is greater than zero for an isolated system.
对孤立系统,熵的变化是大于零的。
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We add heat to the system.
我们对系统加热。
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The total work is less than zero.
说明系统对外界做功。
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Under-nutrition--now I'm going -this slide has a lot of information on it and I'm going to come back to it in the class where we talk about hunger, but I show it today because of course undernutrition can affect every single system of the body and can have devastating consequences on people's health.
营养不良,这张幻灯片上有很多关于营养不良的信息,以后讲到饥饿的时候,我会再回头来讲这张幻灯片,我今天让大家看是想告诉大家,营养不良一定会影响身体的每一个系统,并对人们的健康造成巨大的破坏
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Delta v is positive in this direction here, the work is negative. So work on the system is positive. Work done by the system is negative.
功是负的，总而言之,外界对系统做功的符号为正。
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Because if it's irreversible, it's very likely that I don't know what the pressure inside the system is doing while this is happening.
因为对不可逆过程，系统内部的压强,没有明确的定义,气体不处于平衡态。
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It's an expansion, so we're doing work against the environment, or to the environment.
压强降低，系统对，外界做功。
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Now, the reason this condition always holds in ordinary mechanics is because you're never, in that case, concerned with a huge statistical population of particles where the disorder among them is an issue.
这个条件在力学中总是成立,这是因为在力学中,我们从来没有关注过大量粒子的统计行为，而对这些系统来说,无序是很重要的。
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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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