If we have a higher z effective, it's pulled in tighter, we have to put in more energy in order to eject an electron, so it turns out that that's why case 2 is actually the lowest energy that we need to put in.

而如果有效核电量更高，原子核的束缚也就更紧，我们不得不输入更多的能量来打出一个电子，这就是第二种情况,所需要输入的,能量更少的原因。

麻省理工公开课 - 化学原理课程节选

So we pulled ten of these favorite issues: four large U.S. companies, three small ones and three international.

FORBES: Smart Money

"Most females tend to have a narrow or thinner waist as it relates to the chest area, so we pulled the waist area in, " said Lt.

MSN: US Army tests body armor for female soldiers

The waves coming off the point break to the north looked good, so we pulled on our 4mm wet suits and paddled out a calm channel just to the south of the break.

FORBES: Paradise Lost