One company has presented an idea in which metal strips inserted in pavements and roads operate fly wheels by means of a pistonaction using hydraulic fluid.
一个公司提出这样想法：嵌在人行道和路面上的金属条用液压活塞的作用使飞轮转动。
2
A reciprocating piston, the inhalation and from a liquid, known as a working cycle; this pump known as the single-action pump.
活塞往复一次，各吸入和排出一次液体，称为一个工作循环；这种泵称为单动泵。
3
Compared to single piston cylinder, it features fast action and flexibility, specially used when large thrust force or tensile force is required within short time.