Model the spherical valvecase with characteristic parameter which is the caliber of the valve, and according to some standards determine other structure sizes and create the data file.
以阀门的口径为特征参数，根据标准确定阀体的其他结构尺寸，并建立数据文件。
2
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。
3
In continued operation the chain can jump a tooth on the drive sprocket or break entirely, with either case resulting in engine damage from valve-piston collisions.