Abstract: When the distance between two nanoparticles becomes less than the mean free path or the characteristic wavelength of radiation，the radiative heat transfer will be several orders of magnitude greater than that between two blackbodies.The remarkable increased radiation energy transfer may be harmful to the performance of super-insulating materials such as silica aerogels with nanoporous structures.Based on the fluctuation-dissipation theorem，the near-field radiation can be suppressed effectively by tuning the adjustable parameters in dielectric function of Drude and Lorentz models.This study is of great significance for investigating the heat transfer of group nanoparticles and developing novel insulating materials with special properties.

Key words: near-field radiation, nanoparticle, dielectric function

摘要： 当两个纳米颗粒之间的距离小于平均自由程或辐射特征波长时，两者之间的近场辐射比黑体辐射大几个数量级。辐射能量的大量传递将显著降低纳米隔热材料的性能。基于涨落耗散定理，通过调节介电函数Drude和Lorentz模型中不同的可调节参数，可有效降低近场辐射传热量。该研究对纳米颗粒簇传热研究与隔热材料的设计具有重要意义。

关键词: 近场辐射, 纳米颗粒, 介电函数