No ballasts , cooling fans or reflectors needed .

没有镇流器，散热风扇或反射器所需要的。

Lenses , filters , reflectors and semi-sealed units for railway signals .

铁路信号用透镜、滤色镜、反射镜及半密封部件。

The photographer should use curtains and reflectors .

摄影师应该用窗帘和反光板。

Design principles and considerations for reflectors and lenses .

反光镜和透镜的的设计原则及考虑。

They then used the movements of the reflectors to analyse who was affecting whom .

然后他们便可通过反射器的运动来分析是谁影响了谁。