But some crystalline materials don't possess a center of symmetry making them candidates for piezoelectricity.

但是一些晶体材料不具有对称中，它们成为压电性的候者。

There are already train stations that use passengers' footsteps to power the ticket gates and displays and a dance club where piezoelectricity helps power the lights.

已经有火车乘客的脚步为检票口和显示屏供电，还有一个舞蹈俱乐部压电技术为灯供电。