Bo Li

为满足当前安防市场对高性能变焦光学镜头在大范围监控和高清成像的需求，设计了一款焦距范围为 10 mm～500 mm 的平滑变焦光学系统。系统采用机械式正组补偿方式，通过参数设定与优化结合的方法计算出初始结构参数，采用移动光阑的方式保持恒定F数；引入非球面透镜，有效矫正系统的位置色差和轴向色差，提升了成像性能；整个系统由13个球面透镜和2个非球面透镜组成，总长为375.6 mm，调制传递函数（modulation transfer function, MTF）在 104 lp/mm 处全程均高于 0.35；给出了变倍组与补偿组的运动曲线，曲线平滑无断点，验证了系统的可靠性与稳定性。最终分析结果表明：该系统能够满足大范围监控的实际需求，为大变倍比变焦光学系统的设计提供了参考。

This article addresses the knowledge gap regarding the effect of Ti addition on the microstructure and corrosion behavior of the LMD-processed GH3536 alloy in a simulated solution of proton exchange membrane fuel cells (PEMFCs). The microstructural evolution, corrosion resistance, and passive film characteristics of LMD-processed GH3536 alloy with varying Ti contents were characterized through a variety of techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), X-ray photoelectron spectroscopy (XPS), and a series of electrochemical measurements. The results indicate that the corrosion resistance of the LMD-processed GH3536 alloy significantly improves with increasing Ti content. However, when the Ti content exceeds 0.2 wt.%, the beneficial effect on corrosion resistance is weakened. Two primary mechanisms explain the enhanced corrosion resistance, involving the heterogeneous nucleation of Ti-modified Al₂O₃ and Ti solute segregation, which promotes grain refinement. In addition, grain refinement can provide more active sites for the formation of compact passive films, thereby improving corrosion resistance of the GH3536 alloy.

The thermal stability of PSCs has been enhanced synergistically by removing BCP, increasing C₆₀ thickness and iconic liquid addition.