针对压缩机出口除油器效率性能评价，提出一种基于光闪烁法的润滑油油雾液滴浓度在线检测方法。基于颗粒系层模型和Lambert-Beer定律，以层测量体透过率作为泊松分布随机变量，推导了光闪烁法在长光程平行光束下的颗粒浓度检测模型。闪烁频率根据测量体大小、颗粒直径和颗粒速度确定，并通过影响闪烁信号的拟合方差影响检测精度。对于某型压缩机润滑油，通过光谱扫描和主成分分析法确定了在可见光波段，400 nm波长光束具有最佳的检测灵敏度和正相关性。实验结果表明，相较于光透射法，在0~50 mg·m^-3油雾浓度范围内基于光闪烁法检测标定结果误差小于10%，线性相关系数R²=0.989。

作者测量了常见军用涂层在Ka波段的发射率，测量对象包括：雷 达隐身涂层、雷达与高发射率红外兼容隐身涂层、雷达与低发射率红外兼容隐身涂层、高发射率红外涂层以及航空防腐涂层。测量试验采用了基于电压法的改进测量方案，该测量方法可以消除材料样品不能完全覆盖天线波束以及参考体与材料样品厚度差异导致的有效辐射面积差异引起的误差。此外，文章分析并讨论了主要的测量不确定度源。

A room temperature sub-bandgap near-infrared (λ>1100nm) Si photodetector with high responsivity is achieved. The Si photodetector features black Si made by wet etching Si (100), Si/PtSi nano-Schottky junction arrays made from black Si/Pt contacts, and chemical and field-effect passivation of black Si. Responsivities are 147.6, 292.8, and 478.2 mA/W at reverse voltages of -1.0,-1.5, and -2.0V for 1550 nm light, respectively, with corresponding specific detectivities being 9.79×108, 1.88×109, and 2.97×109cm·Hz1/2/W. This work demonstrates a practical room temperature sub-bandgap near-infrared Si photodetector that can be made in a facile and large-scale manner.

To achieve radar and infrared stealth, an infrared stealth layer is usually added to the radar absorbing material (RAM) of stealth aircraft. By analyzing the millimeter-wave (MMW) emissivities of three stealth materials, this Letter investigates the impact of the added infrared stealth layer on the originally “hot” MMW emission of RAM. The theoretical and measured results indicate that, compared with the monolayer RAM, the MMW emission of the bilayer material is still strong and its emissivity is reduced by 0.1–0.2 at almost every incident angle. The results partially demonstrate the feasibility of detecting stealth aircraft coated with this bilayer stealth material.