actinic focus

例句：

1. 1.The actinic focus is the point where the sun's rays are most concentrated.
   紫外线焦点是太阳光线最集中的地方。
2. 2.The actinic focus is responsible for the formation of ozone in the stratosphere.
   紫外线焦点负责在平流层中形成臭氧。
3. 3. The actinic focus is a critical component in the production of solar energy.
   紫外线焦点是太阳能生产的关键组成部分。