The author introduces the experience of sketch drawing in the light of his own work in digitized topographic plotting.

笔者结合自己进行数字化测图的具体工作介绍一些绘制草图的经验。

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So, for example, here we're showing rubidium and potassium and sodium plotted where we're plotting the frequency -- that's the frequency of that light that's coming into the metal versus the kinetic energy of the electron that's ejected from the surface of the metal.

让大家看来都是可以理解的事情,就是把不同金属的观测结果,画到一张图里面来，例如这里,我们展示的是钠，钾,铷的频率-这是照射金属的光的频率,和金属表面出射电子动能的关系。

麻省理工公开课 - 化学原理课程节选