If you are measuring high refractive indexes, you may also need to calibrate and adjust using traceable refractive standards1 to2 times a year.
如测量高的折光指数，则每年需要1－次使用可追踪的折光标准进行校准和检定。
Design of catadioptric infrared optical system for tank target tracking and recognition
折反式坦克目标跟踪识别红外光学系统设计
elbow refractor
折轴反光望远镜;折轴折射望远镜;曲折折光计
The world is marching toward brightness and progress. The road is tortuous, but the future is bright.
（2）世界正向着光明和进步的目标迈进。道路是曲折的，前途是光明的。
folding camera (with bellows)
光折合式照相机（带折箱）
Double silver-blue lavender star/ white fluted edge. Glossy, ruffled. Standard.
重瓣，洋紫蓝色镶白边，星型花。有光泽的叶面，皱折边。标准型。
GI(Grated Index)
渐变折射线(光纤)
The study of the refraction of light.
屈光学研究光的折射
Single burgundy sticktite/ white frilled edge. Medium green, pointed, glossy, hairy, scalloped/ red back. Standard.
单瓣不掉落的葡萄酒色花，白色折边。中绿色尖尾扇型叶，叶面光滑多毛，红色叶背。标准型。
stress-induced birefringent optical fiber
应力导致双折射光纤
birefringence fiber with stress rod
应力棒型双折射光纤
fast refractive infrared optical system
快速折射红外光学系统
tunable birefringent filter
可调谐双折射滤光器
The x ray show a fractured ankle.
X 光片显示足踝骨折。
graded index fibre
折射率渐变的光导纤维
graded-index optical fiber
渐变折射率光学纤维
step graded index lightguide
阶梯折射率剖面光波导
The X - ray shows a fractured ankle .
x光片显示足踝骨折。