Characterization of a Viable Particle by Optical Prorerties

本文讨论了一种识别运动大气颗粒物成分的方法。该方法以光学为基础，利用微粒的折射率来识别其组成。进行了数值分析，并对实际粒子(PSL)进行了实验。在数值分析中，评估了通过测量在某两个散射角的散射强度来确定均匀球形粒子的折射率和尺寸的可能性。现在，细菌、水和PSL颗粒都很感兴趣，所以目标颗粒的尺寸参数在2.0到6.0之间，折射率在1.3到1.7之间。前角和侧角的组合比其他组合的测量概率更高。制作了测量实际运动的单个粒子在任意两个散射角下的散射强度的装置(C.A.P.系统)。用C.A.P.系统测量了PSL粒子的散射强度。分析了激光横截面光强分布与PSL粒子运动参数之间的关系对探测光强的影响。得到的强曲线形状类似于高斯曲线，它是以高斯光为光源产生的，其峰值和宽度由粒子的路径决定。然后，在已知粒子直径的情况下，利用PSL粒子在每个探测角度的相对散射强度与30°&gt；的相对散射强度计算了PSL粒子的折射率。

A method to recognize the compositions of moving airborne particles are discussed in this study. The method is based on optics, and refractive indices of paticles were utilized to recognize their compositions. Numerical analisis were performed, and experiments on actual particles (PSL) were made.In numerical analisis, the probability to determine the refractive index and the size of a homogenous spherical particle by measuring scattering intensities at some two scattering angles is evaluated. Now, bacteria, water and PSL partilces were interested, so Objective particles have the size parameter range from 2.0 to 6.0, refractive index range from 1.3 to 1.7. Higher probability of determining them was obtained with the conbination of foward and side angle than that with other conbinations.The insturument (C.A.P.system) to measure the scattering intensities of the actual moving single particle at arbitrary two scattering angles was made. With C.A.P.system, the intensities scattered by PSL particles were measured. The influence on the detected intensity, that was yielded by the relation of the intensity distribution at the cross section of LASER beam and the parh of a moving PSL particle, was evaluated. The obtained intensty curve had a shape like Gaussian curve, it was caused by using LASER that was Gaussian beam for light source, and its peak value and width were determined by the path of particle. So the shapes were utilized to know the parh of particle.Furethermore, the refractive indicies of PSL particles were calculated with relative scattered intensities at each detected angle to intensity at 30^<○> in the case that particulate diameters were Known.