Lead seal with double holes是什么意思

用法例句

Drainae discharge of upward and plumb drainage hole at Permanent Shiplockes in the Three Gorge Project was measured in situ.

结果表明， 仰孔的排水效果明显优于铅孔。

This article discusses the influence on the ability of lead plate perforation caused by the 8# electric detonator s gunpowder loading structure, gunpowder pressing, and the contact patten between gunpowder.

从8#电雷管的装药结构、压药密度、药与药的接触形式等方面,对铅板穿孔能力的影响进行了探讨。