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近年来,激光诱导击穿广谱技术发展迅速。作为一种用于物质成分探测的新技术,它具有简单、快速、无需复杂样品制备、多种元素同时检测等优点,可实现待测样品物质成分现场、在线的检测,在很多领域都极具应用前景。激光诱导击穿光谱特征谱线的分离拟合提取是光谱特征识别与后续元素浓度定量反演研究的基础。为实现激光诱导击穿光谱重叠特征谱线的有效分离拟合提取,采用阻尼最小二乘法,分析并确定了迭代前的初始拟合参数值,实现了在重叠特征谱线情况下对某火力发电厂粉煤灰中的铬元素特征谱线的分离提取。阻尼最小二乘法基于高斯-牛顿迭代,在迭代步长中引入阻尼因子,在迭代的过程中根据每一步迭代后所反馈的信息动态的调整迭代步长,从而有效防止了迭代的发散,保证了迭代的快速收敛,最终使得元素特征谱线拟合提取的效果更佳、所得到的特征谱线强度值更准确。分别采用阻尼最小二乘法和最小二乘法对不同浓度的样品中铬元素特征谱线进行分离拟合提取并给出特征谱线的强度值,作出特征谱线强度值关于元素浓度的定标曲线并对比两种方法所得结果的线性相关性。结果表明,阻尼最小二乘法所得结果的线性相关性更高,该方法稳定、可靠,适用于激光诱导击穿光谱重叠特征谱线的分离拟合提取。
In recent years, laser-induced breakdown of broad-spectrum technology has developed rapidly. As a new technology for the detection of material components, it has the advantages of simple, rapid, without complex sample preparation, simultaneous detection of multiple elements, etc., which can detect on-site and on-line substances in the sample components under test and has great potential in many fields Application prospects. The separation and fitting extraction of laser-induced breakdown spectra is the basis of spectral feature recognition and subsequent quantitative inversion of element concentration. In order to realize the effective separation and fitting extraction of the overlapping spectrum of laser induced breakdown spectroscopy, the least square method was used to analyze and determine the initial fitting parameters before iteration, Separation and Extraction of Chromium Elements in Fly Ash from Factory. Damping least square method based on Gauss - Newton iterative, the introduction of damping factor in the iterative step, the iterative process according to the information fed back after each iteration iteratively adjust the step size, thus effectively preventing the iterative divergence, to ensure that The rapid convergence of the iteration finally makes the fitting and extraction of the element characteristic lines better and the resulting intensity of the characteristic lines more accurate. Damping least square method and least square method were respectively used to separate and extract the characteristic lines of chromium in different concentrations of samples and to give the intensity values of the characteristic lines and to make calibration curves of the characteristic line intensity values with respect to the element concentrations Compare the linear correlation of the results obtained by the two methods. The results show that the results obtained by damping least square method have a higher linear correlation, and the method is stable and reliable. It is suitable for the separation and fitting extraction of the overlapping characteristic lines of laser-induced breakdown spectroscopy.