Lucas R J, Twersky V
Mathematics Department, University of Illinois, Chicago 60680.
J Acoust Soc Am. 1987 Sep;82(3):794-9. doi: 10.1121/1.395276.
Recent results for low-frequency scattering by correlated random distributions of nonspherical particles averaged over orientation are applied to invert ultrasonic data for red blood cell suspensions under different flow conditions. The inversion procedure isolates a correlation parameter (c) representing a process in which the volume fraction (w) of particles increases linearly, and also a cell population parameter P. Reduced data records of scattering versus hematocrit are compared with S(c;w)P, where the generalized fluctuation function S is proportional to the variance in particle number, and P is proportional to the backscattering cross section of an isolated particle. The peak scattering for the different flow processes occurs at values of w ranging from about 0.15 for the most uniform to 0.25 for the least, corresponding to c values of about 2.1 to 0.4, as compared with w approximately equal to 0.13 and c = 3 for hard (repulsive at contact) spheres or aligned ellipsoids. The lower values of c suggest weaker repulsion between the deformable cells and effective interparticle attraction (aggregative trends), and c approximately equal to 2 may also involve flow alignment of the discoids.
近期关于非球形粒子的相关随机分布在取向平均下的低频散射结果，被应用于反演不同流动条件下红细胞悬浮液的超声数据。反演过程分离出一个相关参数（c），它代表粒子体积分数（w）呈线性增加的过程，以及一个细胞群体参数P。将散射与血细胞比容的简化数据记录与S（c；w）P进行比较，其中广义涨落函数S与粒子数的方差成正比，P与单个粒子的后向散射截面成正比。不同流动过程的散射峰值出现在w值范围，从最均匀时的约0.15到最不均匀时的0.25，对应的c值约为2.1到0.4，相比之下，硬（接触时排斥）球体或排列的椭球体的w约等于0.13且c = 3。较低的c值表明可变形细胞之间的排斥较弱以及有效的粒子间吸引力（聚集趋势），并且c约等于2可能还涉及盘状细胞的流动排列。
