基于Mie散射光强的多角度动态光散射复合角度加权方法

Multiple Angle-weighting Based on Mie Scattering Intensity in the Multiangle Dynamic Light Scattering

针对多角度动态光散射测量技术中通过Mie散射光强计算的角度权重估计方法存在信息利用率与抗噪性之间的矛盾,提出利用每一角度所有粒度的整体Mie散射空间特征进行角度加权和利用每一粒度对应Mie散射光的细节特征对核矩阵做元素加权的复合角度加权方法,并结合正则化方法进行了模拟和实测的多角度动态光散射数据反演.与采用光强比值法和光强均值法的反演结果比较表明,多角度动态光散射反演结果与角度加权方法密切相关.无噪声影响时,光强比值法和复合角度加权法都能得到准确的颗粒粒度分布,但光强均值法信息利用率不高;随着噪声水平的提高,光强比值法反演结果急剧变差,表现出较低的抗噪性能.复合角度加权方法通过兼顾信息利用率和抗噪性能,使得增加散射角时信息增多的优势得以更好地显现,并且有效地抑制了角度增多带来的噪声影响.该加权方法显著提高了多角度动态光散射进行颗粒测量,特别是对多峰分布颗粒体系测量的准确性.

In order to solve the problem on the information utilization and noise reduction of angular weighting methods by Mie scattering calculation for multiangle dynamic light scattering,multiple angleweighting method was proposed,in which the Mie scattering′s spatial character of all granularities at each angle is as the angular weighting factor and that of each granularity is as the nuclear matrix weighting factor.By using this multiple angle-weighting method,the regularization inversions for both simulated and measured multiangle dynamic light scattering data were carried out.Compared with the inversion results of the light intensity ratio method and the light intensity mean method,the inversion results for multiangle dynamic light scattering are closely related to the angular weighting methods.In the absence of noise,the intensity ratio method and the multiple angle-weighting method can obtain accurate particle size distributions,but the information utilization for the light intensity mean method is not sufficient.With the increase of the noise level,the inversion results of the ratio of light intensity are rapidly getting worse,which shows the lower noise reduction capability.Multiple angle-weighting method,taking the information utilization and noise reduction capability into account,can better show the advantage for increase of information and effectively suppresses the noise influence when the scattering angles are increased.The method significantly improves the accuracy of particle measurement in the multiangle dynamic light scattering,especially for the multi-peak distribution particle system.