战略级任务必须保持发射率每年一到三次发射。

Strategic-level missions must maintain a launch rate of one to three launches per year.

结果表明，基板选择和薄膜厚度是影响发射率的重要因素。

It showed that the nature of substrate and the thickness of the film were important to the emissivity.

目标的红外辐射强度是由目标表面温度和目标表面发射率两个因素决定的。

The IR radiation intensity of target depends on the temperature and the IR emissivity of it.

在热红外扫描图像的判读工作中，热红外发射率是一个极为重要的影响因素。

The emissivity of natural meterial is a important factor in the interpretation of thermal image.