Within a constant shell, it varies from left to right, maximally taking value at the right extreme.

在一个固定的层里，它会从左往右变化，在最右边时达到最大值。

麻省理工公开课 - 固态化学导论课程节选

In addition to that, we have that epsilon nought value, remember that's the permittivity constant in a vacuum, and basically that is what we use as a conversion factor to get from units. We don't want namely coulombs to units, we want that will allow us to cancel out in this equation.

这是电子的电荷，此外，我们有epsilon零，记住这是真空的介电常数，这是我们用来转换单位的转换常数,我们不想用库伦单位，我们希望这个可以在方程中约去它。

麻省理工公开课 - 化学原理课程节选