If the electron flow takes place in a vacuum, as in the case of electronic valve, the electrons will travel at considerable speed, since little resistance is offered the medium.
如果电子在真空里流动，比如电子真空管，那么电子的运行速度非常快，因为介质对电子几乎不产生什么阻力。
2
This advanced technology TFM Lined valve is specially designed and produced for applications requiring high purity and maximum chemical resistance.
这种高技术TF M内衬蝶阀特别适用于要求高纯度和最高耐化学品特性的应用场合。
3
Be sure to use proper valve material-types for both temperature and chemical resistance.