带壳球形颗粒复合介质的有效介电响应

EFFECTIVE DIELECTRIC RESPONSE OF THE COMPOSITES OF COATED SPHERICAL INCLUSIONS

本文对线性（或非线性）的带壳球形颗粒分布于一线性基质的复合介质的线性（或非线性）有效介电响应进行了研究．以前的研究表明，在与核和壳的介电性质有关的条件下，这种三元复合体系（带壳）可等价于一个二元体系（不带壳），然而，研究结果表明，当壳和基质的介电性质满足一定条件时，该三元复合体系也能等价于无壳实心球颗粒无规分布于原来的基质中的一个二元复合体系．这个等效的无壳实心球颗粒半径比上述三元复合体系中的球核颗粒大。若核颗粒为非线性材料，则满足一定条件时，该复合材料的体非线性介电响应也可得到增强．最后，我们讨论了带壳的球状颗粒复合介质的有效介电常数的依赖关系。

The effective dielectric response of linear (or nonlinear) composite system, which is composed of coated sphere particles with linear (or nonlinear) cores and linear shells randomly embedded in a linear host matrix,is investigated. It has been found that such three-component system could be equivalent to a two-component composite under certain condition which is associated with the properties of cores and shells. However we find that when the properties of shells and host satisfy certain condition, this threecomponent composite can also be equal to equivalent solid spheres without shells embedded in the same host matrix. The equivalent solid sphere's radius is larger than the original core's and its dielectric function has simple relation to the dielectric function of the core. If the core is nonliear, when the special condition is satisfied, the bulk nonlinear dielectric response of the composite may also be greatly enhanced. And we discuss the dimension dependence of effective dielectric function in the composites of coated spherical inclusions.