人们发现，在一些保存着太阳系原始化学成分的陨石中，铱元素的含量很高。

Ir is found in high concentrations in some meteorites, in which the solar system's original chemical composition is preserved.

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您需要使用其他方法将该子元素从局部坐标系转换到内容坐标系。

You need some extra methods to convert that item from its local-coordinate system to its content-coordinate system.

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然后，在uv坐标系内，把面积元素定义为dA，只是为了让他们看起来不同。

And, the area element in uv coordinates, let me call that dA prime just to make it look different.

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So, remember when you're looking at your periodic table, don't forget about the lanthanides, sometimes they come into play.

因此，要记住，当你在看元素周期表时，不要忘了镧系元素，有时候也会用到它们。

麻省理工公开课 - 化学原理课程节选

And if you remember this phrase, I don't know why you would, but this will help you learn the lanthanides in order.

如果你能记得这句话的话，我不管你们是怎么做到的，但是这个确实会帮助你按顺序记住镧系元素。

麻省理工公开课 - 固态化学导论课程节选

As soon as lanthanum takes that electron, this level rises ever so slightly, and then we jump down here and fill in the lanthanide.

一旦镧得到了电子，这一层就会稍稍上升，然后我们向下填一下镧系元素。

麻省理工公开课 - 固态化学导论课程节选