Palmes E D, Burton R M, Ravishankar K, Solomon J J
Am Ind Hyg Assoc J. 1986 Jul;47(7):418-20. doi: 10.1080/15298668691389973.
A simple mathematical model of the molecular basis for the function of a diffusional sampler for dilute mixtures of gaseous contaminants in supporting gases is presented. The model is based on the movement of single molecules of the contaminant between sections of a tubular diffusion path on a step-by-step basis; the length of the step and of each section of the tube are equal to the mean free path, lambda, under the specified conditions. When the model is used, the coefficient of diffusion, D, can be calculated from lambda and the average velocity, v, of the contaminant molecule. Both lambda and v were calculated independently using equations which involved the minimum number of assumptions. The value of D so estimated was of the same order as that in the literature, differing by a factor of less than 2. It should be emphasized that the model represents a statistical, thermodynamic approach to understanding diffusional samplers, and its utility is independent of the means of estimating lambda and v for specific gas pairs.
本文提出了一种用于支撑气体中气态污染物稀混合物的扩散采样器功能分子基础的简单数学模型。该模型基于污染物单分子在管状扩散路径各部分之间逐步移动；在指定条件下，步长和管的每一部分长度均等于平均自由程λ。使用该模型时，扩散系数D可根据λ和污染物分子的平均速度v计算得出。λ和v均使用涉及最少假设数量的方程独立计算得出。如此估算的D值与文献中的值处于同一量级，相差不到2倍。应当强调的是，该模型代表了一种理解扩散采样器的统计热力学方法，其效用与针对特定气体对估算λ和v的方法无关。
