An open system, as the name describes, allows mass and energy to freely flow through the boundary.

开系，顾名思义，允许质量和能量自由地,流过它的边界。

麻省理工公开课 - 热力学与动力学课程节选

Mass and energy flow through boundary.

质量和能量流过边界“

麻省理工公开课 - 热力学与动力学课程节选

The pink line here is the efficient portfolio frontier when we have only stocks and bonds to invest.

这条粉色曲线就是有效边界,这个投资组合只包括了股票和债券。

耶鲁公开课 - 金融市场课程节选

The plane crashes exactly on the border of Canada and the United States.

飞机刚好,在加拿大和美国的边界上坠毁

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Remember, I said when we do a bisection method, we're assuming the answer lies somewhere between Well, what is the square root of a quarter? It is a half.

记住，我提过当我们用二分法的时候,我们假设答案处于,上边界和下边界之间,0。25的平方根是多少？,是0。5。

麻省理工公开课 - 计算机科学及编程导论课程节选

But when that's not true, then there is a typical sort of modern frontier, a land bridge which there a line is-a theoretical line is drawn through it, and on one side is one city, and the other side is another city.

但还不止这些天然边界,另外还有种边界形式,和现代国境线很类似,是由一座陆桥,分割出一条界线…假象的界线,界线的一边是一个城邦,另一边是另一个城邦

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You have discribed the border as a safe where things the Taliban just go over there, when they are chased by the Afghan troops and Nato and then they come back then things are a little bit cooler.

您把这个边境线描写成一个关卡,当塔利班分子被阿富汗和北约军队追击时，他们就越过边界线,风声不紧时，他们又通过这个关卡回来。

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So this becomes where defining the system and the boundaries and everything becomes important.

因此问题就变成了,如何定义系统和边界,那么一切都变得重要了。

麻省理工公开课 - 热力学与动力学课程节选

In fact, I have it--suppose we have three assets and we want to compute the efficient portfolio frontier, the mean and variance of the portfolio.

事实上，假如我们拥有三种资产,我们想计算有效边界，及投资组合的均值和方差。

耶鲁公开课 - 金融市场课程节选

And then between the system and the surroundings is the boundary.

系统和环境之间的,是边界。

麻省理工公开课 - 热力学与动力学课程节选

So that's the expected return and efficient portfolio frontier problem.

这就是预期收益,和有效边界问题。

耶鲁公开课 - 金融市场课程节选