体布拉格光栅是一种透明介质，其折射率呈周期性变化。体布拉格光栅（Volume Bragg Grating, VBG）激光二极管利用了VBG作为反馈元件，以实现窄线宽和波长选择性的激光输出。其工作原理主要基于布拉格衍射条件和光学反馈机制。 一般地，半导体激光器的出射光 ...

The hypothesis is that the breathing pattern during a progressive treadmill exercise is independent of the protocol, at least in healthy people, and can be assessed using a nomogram. Conclusions: ...