If you compare the s orbital with the bottom lobe, these have a different sign so they're going to destructively interfere.

如果你们比较s轨道和下面这叶，它们正负号相反，所以它们相消干涉。

youdao

Realistic signals are made by summing sine waves of lots of frequencies, so that after some finite number of wavelengths they interfere destructively and you get a signal of finite width and duration.

现实中的信号由各种频率的正弦波组成，因此，在有限的波长数后，它们会干涉相消，你就得到一个有限宽度和有限延续的信号。

youdao

Realistic signals are made by summing sine waves of lots of frequencies, so that after some finite number of wavelengths they interfere destructively and you get a signal of finite width and duration.

现实中的信号由各种频率的正弦波组成，因此，在有限的波长数后，它们会干涉相消，你就得到一个有限宽度和有限延续的信号。

youdao