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心，这使它们成为压电性的候选者。

In most non-piezoelectric crystalline materials, the atoms in their unit cells are distributed symmetrically around a central point.

在大多数非压电晶体材料中，其晶胞中的原子围绕中心点对称分布。

An LED is a type of diode or semiconductor device that emits light when electrons flow through layers of crystalline inorganic material.

LED 是一种二极管或半导体器件，当电子流过结晶无机材料层时会发光。

To do that, researchers would need a perfectly crystalline material, and would need to control the size of the nanomaterial very precisely, sculpting it atom layer by atom layer.

为此，研究人员需要一种完美的晶体材料，并且需要非常精确地控制纳米材料的尺寸，逐个原子层地对其进行雕刻。