Study On The Difference Of Light Scattering And Scattering Characteristics Identification Of Spherical Particles

It is more and more important that particle characteristic just like size and property is detected in the field of material,chemical industry,air quality monitoring and so on.Light scattering method is widely applied in particle measurement because it has advantages of high speed of measurement,good precision,good repeatability and feasibility for on-line and non-contact measurement.The light scattering intensity of spherical particles is affected by particle size,property and so on.Particle size is gotten from light scattering intensity without considering the related affection caused by particle size and property.Simultaneous detection of particle size and property can eliminate the related affection between size and property,which can also improve the accuracy of size detection and realize property detection.It can lay the foundation for in-depth research of the related affection between size and property.For the size and property identification of different particles at the same time,the spherical particles with the size of 0.1-10.0μm are objects of study in the paper.The light scattering differences of different particles and characteristic quantity that can identify the scattering characteristic is researched.Around the identification method,a series of research work has been done in this paper,and the main contents are as follows.1.The difference of light intensity distribution in 0-180° is obtained by simulating the scattering intensity distribution of particles with different sizes and properties.Analyzing scattering intensity distribution of different particles with different sizes separately,the factors affecting light intensity is researched especially at the small angle 0-15° specially.For absorbent and non-absorbent particles,the difference of light intensity is analyzed by simulating the relationship curve between grain size and intensity curve at small angle which is 10°.2.For the particles with different sizes,the difference of light scattering signal is mainly the difference of the overall scattering light intensity amplitude in 0-1800°.In order to study the characteristics of this difference,a new method is proposed to calculate the light scattering signal by fractal theory.Based on EMD,the fractal dimension of different particles with different sizes and same properties is calculated.3.For the particles with different properties,the difference of light scattering signal includes the distribution position of peak value of the scattering intensity,oscillation of scattering curve.In order to identify the difference,three-dimensional energy sample entropy is involved.Based on the calculation of sample entropy,a series of signal processing operations are carried out.Three dimensional energy sample entropy of particles with different properties is calculated based on the simulation and experimental.4.For the light scattering of particles with different size and properties,because of the variety and complexity of characteristics,time-frequency nonlinear eigenvectors are used to find the difference of light scattering and GRNN is used to identify the sizes and properties of particles.In order to prove the methods effective,the sizes and properties are identified based on the simulation.5.Single particle angular scattering detection device based on multi-angles is designed.The light scattering signals are measured by the device.By extracting the characteristics quantities from the datas and experiments including qualitative and quantitative test,the feasibility and accuracy of the method in the thesis is proved.