游泳池过滤水处理设备

普利卡管可以给我们的使用提供什么方便呢？

As soon as he had spoken, the Tin Man began to chop, and in a short time the tree fell over with a crash, whereupon the Scarecrow's clothes fell out of the branches and rolled off on the ground. Dorothy picked them up and had Winkies carry them back to the castle.

电磁屏蔽室 
：电磁是怎么影响火车的 ？