That quantity in parenthesis, I have a mass which is a positive number. Something raised Something raised to the fourth power has got to be positive.

顺便说一句,质量这个量是个正数,四次方的值,肯定是正数。

麻省理工公开课 - 固态化学导论课程节选

12 That gives it a mass number of 312.

所以它的质量数为。

麻省理工公开课 - 固态化学导论课程节选

We had a great number of mass.

我们有很多受众。

斯坦福公开课 - Twitter之父Jack.Dorsey演讲：好奇和灵感的力量课程节选

n So the velocity is given by this product of the quantum number n Planck constant 2 pi mass of the electron time the radius of the orbit, which itself is a function of n.

速度是量子数,普朗克常数2π乘以轨道半径的值,它自身也是n的函数。

麻省理工公开课 - 固态化学导论课程节选