In-situ analysis of laser-induced breakdown spectra for online monitoring of femtosecond laser machining of sapphire

Laser-induced breakdown spectroscopy(LIBS)is widely used for elemental analysis.However,its application for monitoring and analyzing a laser machining process by examining the changes in spectral information warrants further investigation.In this study,we investigate the effect of laser parameters on the spectra,variations in the time-resolved plasma emission spectra,and the relationship between the morphology of craters and plasma plume evolution during the femtosecond(fs)laser ablation of sapphire.The Boltzmann plot method and Stark’s broadening model are employed to estimate the temporal temperature and electron density of the plasma plume,revealing the process of plasma evolution.This study aims to demonstrate the feasibility of LIBS for online monitoring of laser processing through experimental data and theoretical explanations.

激光诱导等离子体煤炭全组分测量系统的研究

煤炭灰分是选煤厂生产过程中的核心指标,实时在线获得煤炭灰分对选煤厂智能化建设具有重要意义。研究从研制基础核心元器件出发,在系统集成、系统控制、光谱-灰分计算模型和算法等方面开展研究,开发了空气冷却的Nd:YAG固体激光器、高效率反射光栅光谱仪、透射光栅光谱仪和适用于高基体效应条件下的光谱成像技术,建立了在线测量的光谱处理算法和光谱-灰分计算模型,最终研制出激光诱导等离子体煤炭全组分测量系统。吕临能化选煤厂工业性试验结果表明:该系统操作简单,维护方便,工作效果稳定,系统检测结果与化验结果最大误差为1.06%,平均误差为0.373%;对于同一煤样,系统检测结果与化验结果的平均误差在0.3%以下,再现性测试结果误差低于0.2%,准确度和测量精度均符合标准规定;使用该系统指导生产后,可使月平均浮选精煤产率提高0.7个百分点,月平均浮选药剂用量减少18 g/t。