If there is a bulk mixing of the layers of gas in the tube by mechanical stirring or because of a density gradient, mass transfer occurs primarily by the mechanism of forced or natural convection.
Interference with a new coating process, than the average gradient film better performance vacuum tube collector.
采用全新干涉镀膜工艺，比普通渐变膜真空管集热性能更好。
3
The effects on the underwater sound attenuation by the thickness and concentration gradient of polymers were measured in a sound tube at different frequency during the polymers dissolution process.