一、引言磷化氢毒气具有扩散速度快,而且方向性不强的特点,它在密封粮堆内的主要扩散形式有二种。一是赖于高密度向低密度扩散的方向进行扩散,二是伴随温差产生的热力对流进行扩散。在粮堆内影响这二种扩散形式的因素是多方面的,如粮食自动分级、密度与空隙度、 I. Introduction Phosphine gas has the characteristics of fast diffusion and low directivity. It has two main types of diffusion in the sealed grain piles. One is to rely on high-density diffusion to the direction of low-density diffusion, the second is accompanied by the temperature difference between the heat convection spread. Factors that affect these two forms of proliferation within the food piles are manifold, such as automatic grading of food, density and porosity,