So, it's the x-y plane, you can see there's no electron density anywhere there.

它在ｘｙ平面，你们可以看到在这里没有电子密度。

麻省理工公开课 - 化学原理课程节选

But if you go on a plane which is accelerating, you're no longer inertial.

但如果你上了一架加速飞行的飞机,你就不再处于惯性状态了

耶鲁公开课 - 基础物理课程节选

And when we look at this, it's actually split by what's called a nodal plane, which is pointed out in light orange here on this picture, but what we just mean is that there is this whole plane that separates the two lobes where there is absolutely no electron density.

我们来看这里，实际上它被一个节面分开，在这图里用淡黄色表示，这意味着这个分开,两个叶瓣的平面上,是完全没有电子密度的。

麻省理工公开课 - 化学原理课程节选

The reason that it's sigma is if you look at the bonding axis here, is that there is no nodal plane along the bonding axis.

它是sigma键的原因是,因为如果你看键轴，上面是没有节面的。

麻省理工公开课 - 化学原理课程节选

But in sigma orbitals, you have no nodal planes along the bond axis, so if we had a nodal plane here, we'd see an area where the wave function was equal to zero.

但在sigma轨道里，沿着轴向是没有节点平面的，如果我们有个节点，我们就会看到某个地方波函数等于0。

麻省理工公开课 - 化学原理课程节选