【摘要】 流动吸附法测定比表面是近年来发展起来的快速、准确而又方便的比表面测定方法,但此法在测定小表面时会出现反常峯,使准确测定带来困难。本文分析研究了反常峯出现的原因,主要是由于温度梯度的存在引起He—N₂气体的热扩散分离所造成的。文中对热扩散分径向和纵向进行了分析,从而得出了径向扩散造成的反常峯是正反峰面积相等的,纵向扩散造成的N₂在样品管中的积累量很小,计算时可以忽略,从而对小表面测定出现的反常峯进行正反峯面积代数和的方法计算吸（脱）附峯面积,再求比表面,测定的结果与实际情况符合,实现了对小至0.01M²的小表面的准确测定。更多还原

【Abstract】 Flow adsorption method, developed recently, is a quick, accurate and convenient method for the determination of specific surface area. But anomalous peaks appear when small surface area is being determined; this, of course, will effect the accuracy of the result. The reason of the appearance of the anomalous peaks is analysed in this article.It is found that the appearance of the anomalous peaks is mainly caused by the temperature gradient in the sample tube, from which thermal diffusion separation of He-N2 diffusions. Longitudinal and radial thermal diffusions are analysed separately. The anomalous peaks caused by radial thermal diffusion is found to have equal positive and negative peak areas. The accumulative amount of N2 in the sample tube caused by longitudinal thermal diffusion is so small that can be neglected in calculation. Therefore, in determining small specific surface area, the area of adsorption (desorption) peaks and thus the specific surface area are obtained by calculating the algebraic sum of the areas of the positive and negative peaks when anomalous peaks appear. In this way satisfactory result can be obtained and it makes possible to determine surface area as small as 0.01M2.更多还原