中文摘要：

本文针对核污染扩散问题,建立了对放射性粉尘在空气中传播方向和浓度变化的模型.首先根据质量守恒定律导出无风条件下放射性物质的扩散,然后在扩散模型中应用风速方向上的浓度时间函数,得到改进的扩散模型.模型中考虑到风场影响下的放射性物质扩散规律,采用对流扩散模型,引入时间分数阶偏微分方程,进而通过已知数据分析放射性尘埃对其扩散趋势做出预测.

英文摘要：

In this paper, we construct a differential model to describe the variation of densityand propagation of radioactive dusts released from a nuclear power plant. We derived a diffusionequation which models the propagation of the radioactive dusts in accordance with the law of massconservation. Taking account of the wind force and the decay of radionuclide, we improve themodel to establish a fractional order differential equation. With the known data, we determine thecoefficients in the equation and use it to predict the influence of the radioactive dusts to differentregions in China.