颗粒群光散射脉冲信号统计参数分形特征

Fractal Characteristic of Statistic Parameter of Particles' Scattering Pulse Signal

与不规则颗粒对应的随机脉冲信号计数分布是颗粒群粒度分布的完整反映。以幅度、宽度两个相对独立的特征参数为基础,研究了散射光脉冲信号计数分布的统计特性。利用激光尘埃粒子计数光电传感器对空气中尘埃粒子产生的散射光脉冲信号的幅度、宽度分布进行了统计测量,实验结果表明脉冲信号的统计分布不具有中心对称性,其幅度和宽度的计数分布都是满足对数正态分布规律。对数正态分布规律是测量过程中随机作用的具体表现。进一步的计算结果可证明,不规则颗粒群特征参数幅度和宽度之间存在分形结构关系,其分形维数为两者计数统计离散度的比值。

The scattering pulse signal counting distribution generated by the irregular particle is the full reflection of particle size distribution.On the basis of two parameters-amplitude and width,the statistic characteristic of the random pulse signal is studied.The laser particle counter photoelectric sensor is used to measure the amplitude and width of the scattering pulse signal which is generated by the aerosol particles in air.The experimental results indicate that the statistical distribution of the pulse signal is not axis-symmetrical but lognormal distribution which is a specific exhibition of the random effects in measurement.It shows that it has fractal structure relation among the characteristic parameters of the non-spherical particles.In particular,the fractal dimension is the statistical dispersion＇s ratio of the amplitude and width of the scattering light pulse.