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

So in this case, we don't have enough energy to eject an electron, so, an electron is not ejected.

所以在这种情况下，我们没有足够的能量,去逐出一个电子，这样没有电子被逐出。

麻省理工公开课 - 化学原理课程节选

You need energy to move your arms around and move around mechanical systems, obviously, cars, boats, etcetera.

你需要能量,来移动胳膊和走动,机械系统，汽车，船等等。

麻省理工公开课 - 热力学与动力学课程节选

Alumina is really stable, which is why it takes so much energy to make aluminum.

矾土相当稳定，这就是为什么需要消耗大量的能量制备铝了。

麻省理工公开课 - 固态化学导论课程节选

For birds and mammals, we don't have many kids but so we devote a huge amount of psychological energy to protecting the ones that we have.

鸟类和哺乳类，没有很多孩子,所以我们用大量的心力,去保护我们有的孩子。

耶鲁公开课 - 心理学导论课程节选

And if that's the case, why in the world would--can we justify all that shipping, all the excess energy to taste, to ship water in from France, rather then just buying something local or drinking water out of the tap?

既然如此,为什么还会有世界范围的进出口呢,为什么还要浪费能源,从法国进口呢,而不是买当地的品牌,或是直接喝水龙头里的水呢

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

So you can imagine that adds real excitement and energy to the class and puts a little bit pressure on the professors to make sure that we have something worth coming half way around the world for.

可以想象,为课堂带去的兴奋和活力,也给教授施加了压力，我们要确保,能传授值得绕半个地球赶来学习的知识。

哈佛公开课 - 幸福课课程节选

We're to be focusing on building alliances to develop secure energy supplies for the next 20 to 30 years.

我们应该集中精力发展联盟,保证能源供应安全,在今后的20到30年。

普林斯顿公开课 - 国际座谈会课程节选

Now, your temptation is to keep the first answer because you know energy is not going to be negative.

你肯定想保留正根,因为你知道能量不会是负值

耶鲁公开课 - 基础物理课程节选

If I'm going to be active in terms of managing my portfolio, should I spend my time and energy trying to beat the bond market?

如果我想主动地管理我的投资组合,是否应投入时间和精力,专注于战胜债券市场呢

耶鲁公开课 - 金融市场课程节选

The closed system allows energy to transfer through the boundary but not mass.

闭系允许能量通过它的边界传递,但质量不行。

麻省理工公开课 - 热力学与动力学课程节选

So we can use an equation to relate the incident energy and the kinetic energy to the ionization energy, or the energy that's required to eject an electron.

因此我们可以用一个公式将入射能量,与动能和电离能，就是发射出一个电子所需要的能量关联起来。

麻省理工公开课 - 化学原理课程节选

The boundary is impervious to transfer of heat like a thermos Anything that happens inside of the thermos is an adiabatic change because the thermos has no connection in terms of energy to the outside world.

边界不能传递热量,像热水瓶一样,热水瓶里发生的任何事,都是绝热变化,因为热水瓶与外部世界,没有能量方面的联系。

麻省理工公开课 - 热力学与动力学课程节选

We would expect the ionization energy to decrease, that means that sulfur has our lowest ionization energy.

我们预期电离能会降低，这就意味着硫的电离能最低。

麻省理工公开课 - 化学原理课程节选

It is a free electron so there is no potential energy to be accounted for.

对于自由电子,因此没有什么势能。

麻省理工公开课 - 固态化学导论课程节选

So, if we want to go from that stable state to that less stable state, we need to put in a certain amount of energy to our system, that difference between the free electron and the electron bound to the metal.

所以，如果我们想使电子,从稳态到达不够稳定的状态，我们需要引入一定数量的,能量到系统中，即自由电子和束缚于金属的,电子的能量差。

麻省理工公开课 - 化学原理课程节选