top ring是什么意思

用法例句

The structure characteristic & optimization of locomotive diesel engine piston top rings;

机车柴油机活塞环顶环结构特点及其优化

"A ball over three circles", a device for demonstrating persistence of vision andcolour blending, is introduced in this paper,and is presented the making and operation of the de-vice.

本文介绍一种演示视觉暂留现象和颜色合成的实验装置——三环顶球,简述该装置的制作过程和操作方法。