Study On The Infrared Extinction Performance Of Polydisperse Biological Particles

As an important means of countering infrared reconnaissance,guidance and tracking systems,artificially prepared infrared matting materials have become the object of research in various countries,and staged research results have been achieved.Different from traditional matting materials,artificially prepared biological matting materials have the characteristics of controllable morphology and structure,low cost,easy batch preparation,environmental protection and non-toxicity,which is a kind of environmentfriendly extinction materials with great development prospects.The electromagnetic attenuation characteristics of biological materials are determined by the composition and structure characteristics of biological particles.At present,there are a large number of theoretical and technical research achievements,but there are still some shortcomings in the current stage of the research,some of the research is not in-depth,and there are relatively few studies on the dispersion and hygroscopicity of biological particles.In view of the current research status,this article mainly conducts research from the following three aspects:(1)Artificially prepare the same biological materials with different dispersibility,obtain the particle size distribution of the particles in the two materials,and calculate the extinction coefficient of the polydisperse biological particle system based on the test results.At the same time,materials with different distributions are mixed in different proportions,and the extinction coefficient of the new particle system is calculated according to the mixed particle size distribution.And verify the accuracy of the results through dynamic experiments.(2)Construct the spatial structure of polydisperse biological agglomerated particles,and calculate the parameters such as the radius of gyration,porosity,and equivalent complex refractive index of the polydisperse biological agglomerated particles.The discrete dipole approximation method is used to calculate the extinction coefficient of the infrared waveband,and the influence of porosity,original particle number and particle size distribution on the infrared extinction characteristics of agglomerated particles is analyzed.(3)According to the difference in the hygroscopicity of biological materials,the hygroscopic growth model of hydrophilic and hydrophobic biological particles was constructed respectively,and the change rule of the complex refractive index with relative humidity was explored.According to the calculation results of particle size and complex refractive index,a polydisperse agglomerated particle model was constructed to calculate the extinction characteristics under different conditions.Based on theoretical analysis and simulation,two representative biological particles,TL1208 spores and AC0126 spores,were selected for dynamic experiments,and the changes in the mass extinction coefficients of the two biological materials were studied by controlling the humidity value in the experiment box.The main innovations of this paper:(1)Construct the spatial structure model of polydisperse biological particles according to the test results of the biological particle scanning electron microscope image and particle size analyzer.(2)Based on the discrete dipole approximation method,calculate the infrared wavelength extinction parameters of polydisperse bio-aggregated particles with irregular shapes.(3)Construct a hygroscopic growth model of hydrophilic and hydrophobic biological particles,and study the law of their infrared extinction characteristics with relative humidity.