principal ray

He's principal investigator of the Large Area Telescope on NASA's Fermi Gamma-ray Space Telescope.

彼得`迈克尔逊是美国宇航局费米伽玛射线空间望远镜大视场望远镜首席研究员。

Analyses have been made on the principal aspects of high pressure CO2 laser. Several modern preionization techniques have been assessed. In order to develop a high-pressure CO2 laser of high energy output and large beam cross section, the X-ray preionization techniques are more potent.

对高气压CO2激光器的基本情况作了分析，评价了几种现代常用的预电离技术，认为在发展大能量、大束截面的高气压CO2激光器中x光预电离技术是较有潜力的。

A Way of Delimiting Propagation Direction of Extraordinary Ray in the Principal Section

确定主截面内非寻常光传播方向的一种方法

Principal Plane of Ray and principal Section of Crystal

光线的主平面和晶体的主截面

Bear in mind that the chief ray is now principal ray.

记住,此时主光线就是主点光线.