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The International Energy Agency, an intergovernmental energy advisor, has projected an almost in conventional oil production by 2020 and the potential for a serious gap between supply and demand by 2015.
VOA: standard.2009.10.20
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And then the potential energy, the energy is stored here due to the coulombic force of attraction between the electron and the nucleus.
然后说势能,位能其实就是,由电子和原子核之间的库仑引力而形成的能量。
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That is, you minimize potential energy and you see things falling under the force of gravity and so forthgoing to potential energy minima in conformance with this result.
换句话说，你使得势能最小化,然后发现我们关注的东西,在重力或者其他力的作用下下落,直到势能最小的地方,这和我们刚才的结果是一致的。
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The total energy of the system, which we are going to get from postulate number four, which says the energy of the electron, which is the energy of the system, is the sum of the kinetic and the potential energy.
这个系统的总能量，也就是我们将从第四个假设中算出的能量，也就是电子运动产生的能量，也就是整个系统的能量，是动能和位能的总和。
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And we know that n describes the total energy, that total binding energy of the electron, so the total energy is going to be equal to potential energy plus kinetic energy.
我们知道，n是描述总能量的，电子总的结合能，所以总能量，等于,势能加动能。
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You know, if you want to measure the potential energy of something in a gravitational field, you have to define the zero somewhere, right, because it's arbitrary. You can set it anywhere you want. It's the same with enthalpy.
你知道，如果你想测量重力场,中某种东西的势能，你需要，在某处定义一个零点，对吧？,因为势能的值是任意的,你可以把它设定在。
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It means that we better get away from these deterministic models where we have a little electron here with its potential energy and its kinetic energy.
它的意思是我们最好远离,这些确定性模型,那里有一个小电子,它具有势能和动能。
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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。
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The attractive energy is just the potential energy, Coulombic potential.
引力能就是电势能，库伦电势。
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The spontaneous change lowers the potential energy in that case.
在这个例子中,自发变化减小了势能。
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At infinity, there's no stored potential energy, and it drops off more and more negative as one over R.
在无限远处，没有储存的势能，并且它向负方向减少，当距离超过R时。
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So if we say that l is just talking about our kinetic energy part, our rotational kinetic energy, and we know that electrons have potential energy, then it makes sense that l, in fact, can never go higher than n.
如果我们说，l仅仅是,描述动能项，我们的旋转动能，我们知道，电子有势能，所以可以理解，l不能比n高。
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And how about potential energy? It is not bound.
那么什么是势能，答案不是一定的。
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And, in fact, it can't even reach n, because then we would have no potential energy at all in our electron, which is not correct.
事实上，它连n都达不到，因为如果那样的话,电子就没有势能了，这是不可能的。
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What people did is they said let's define a unit of energy that represents a unit charge accelerated across a unit potential difference, and let's call that the electron volt.
前人们所做的就是他们说让我们确定,一个能量单位用来代表一单位电荷,加速穿过形成的一单位电势差，我们叫它电子伏特。
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And the electrical energy is the product of the charge on the electron times the voltage which is the potential difference through which the electron was accelerated. And so this allows me to, by increasing the voltage, increase the energy on the electron.
电子能量是电子上的电荷数,乘以电压的结果,这是种内在的差距,通过它电子运动得以加速，这也让我，通过增强电压，来增加电子能量。
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