Metal sheets that have raised sections will work very well.

VOA: special.2009.04.20

They're studying practical things like marble work, and metal work, and copper work, and not just shipbuilding.

他们学习一些实用的东西,比如大理石打磨,金属冶炼和铜器制造,并且不仅仅是造船术

耶鲁公开课 - 欧洲文明课程节选

So, we do this here for the photoelectric effect, and in terms of the photoelectric effect, what we know the important point is that the incoming photon has to be equal or greater in energy then the work function of the metal.

所以，我们做这个是为了说明，光电效应，在光电效应方面，我们知道的最重要的事情,就是入射的光子能量必须等于,或者大于金属的功函数。

麻省理工公开课 - 化学原理课程节选

now we're not just talking about 1 photon, 1/2 let's say we shoot them all at the same time at our metal, each of them having some energy that's let's say 1/2 the work function. So, just to take a little bit of an informal survey, who thinks here that we will have an electron that is ejected in this case?

我们现在不仅仅讨论一个光子，它们所具有的能量是功函数的，我们在同一时刻把它们打到金属上,我们做一个不太正式的调查,谁认为这种情况下,一个电子会被打出？

麻省理工公开课 - 化学原理课程节选