Now the size of transistors is measured in billionths of a metre .
而现在的晶体管尺寸可用十亿分之一米（纳米）计算。
But the design requires that this silicon layer be no more than five nanometres ( billionths of a metre ) deep .
但此设计要求硅片厚度不超过5纳米（一米的十亿分之一）。
The two substances themselves are arranged in tiny spheres less than 50 billionths of a metre across .
这两种物质本身都放在直径小于50纳米的小球内。
They tweaked the composition , shape and size of the antennae until they arrived at spiral structures a few nanometres ( billionths of a metre ) across .
他们改进天线组的结构、形状和大小，直到最后采用了一些几纳米（十亿分之一米）宽的螺旋结构。
A quantum dot is a semiconductor crystal a few nanometres ( billionths of a metre ) across-about 50 atoms wide , in other words .
