But during the exposure time of red light for 9 h and daylight lamp for 1-2 h, no isomerization of BTM was found, which indicated these two light sources can provide the safe operation of light environment for different experiments. 2. 在红光照射9h及日光灯照射1~2h内BTM几乎不发生异构化,这两种光源可提供安全操作光环境适用于不同的实验。