OK, for constant volume, this is zero.

对于恒定体积过程，第二项等于零。

麻省理工公开课 - 热力学与动力学课程节选

Number two is dissociation energy.

第二项是离解能。

麻省理工公开课 - 固态化学导论课程节选

x1 The portfolio mean and variance will depend on x1 x1=1 in the way that if you put--if you made x1 = 1, it would be asset 1 x1=0 and if you made x1 = 0, then it would be the same as asset 2 returns.

投资组合的均值和方差取决于1,如果你令，投资组合的均值方差就与第一项资产相等1,如果你令，那么它们就会与第二项资产的参数相等。

耶鲁公开课 - 金融市场课程节选