And I am going to call this whole geometric factor here, I am going to put it into one number, and I am going to denote that the Madelung constant.

接下来我将会称这一部分为几何因子，我将把它们整合在一个数字里，我将会标注它为马德隆常数。

麻省理工公开课 - 固态化学导论课程节选

So I realize that the constant, c, is the initial location of the object, and it's very common to denote that by x0.

所以我发现常数c,就是物体的初位移,我们习惯用x0表示

耶鲁公开课 - 基础物理课程节选