反射型光电开关使用时,需要调整反射镜的角____,以取得最佳的____射效果。反射镜反射型光电开关的检测距离可达几米。
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只要不是全黑的物体均能产生漫____射。散射型光电开关的检测距离与被测物的黑度及表面反____率有关,一般只有几百毫米。
在光电断续器中,光的发射器、接收器做在体积很小的同一塑____壳体中,所以两者能可靠地对准,为安装和使用提供了方便,它也可以分为遮____型和反____型两种。
Listen to the dialogue between Mr. Li and Mr. Brown in the Exhibition Hall at the China Export Commodities Fair and choose the best answer to each question.[音频]What is Mr. Li boasting about when Mr. Brown appears in front of his booth?
A. Trousers.
B. T-shirts.
C. Suits.
What advantages does Mr. Li NOT mention about his products?
A. They are modern and elegant in style.
B. They are classic in style.
C. The material retains its luster without becoming shiny.