生物凝聚粒子远红外波段消光特性

针对生物材料FANS 233D，采用显微红外光谱仪测定了材料在2.5~15 m波段的反射光谱，结合Kramers-Kronig （K-K）关系计算了生物材料8~14 m波段的复折射率。利用团簇-团簇模型模拟了不同分形维数的生物凝聚粒子的空间结构，通过离散偶极子近似法计算了具有分形特征的生物凝聚粒子在远红外波段的消光参量，并求出不同条件下生物凝聚粒子的质量消光系数。结果表明:在远红外波段内，相同原始微粒数生物凝聚粒子的分形维数越大，其消光性能越好，当生物凝聚粒子的原始微粒数为50，分形维数为2.00，质量密度为1 120 kg/m3时，质量消光系数最大可达到2.262 m2/g，且凝聚粒子的质量消光系数随着原始微粒半径的增大而缓慢增大。

Extinction characteristics of biological aggregated particles in the far infrared band

The spectral reflectance of biological material FANS 233D in the band of 2.5-15 m was recorded by using infrared microscopic spectrometer. Based on Kramersd-Kronig(K-K) relationship, the complex refractive index of the material in 8-14 m was calculated. A cluster-cluster model was used to stimulate the spatial structure of FANS 233D biological aggregated particles with different fractal dimensions. The extinction parameters of biological aggregated particles with fractal dimension in the far infrared band were calculated by discrete dipole approximation and the mass extinction coefficient was calculated under different conditions. The results indicate that the larger the fractal dimension of biological aggregated particles with the same original particle, the better the extinction performance in the far infrared band. When the value of original particle number, fractal dimension, mass density was 50, 2.00, 1 120 kg/m3 respectively, the mass extinction coefficient in the 8-14 m band can reach 2.262 m2/g. The mass extinction coefficient of the aggregated particles increases slowly with the increase of the original particle radius.