用毛细管成像法测量液相扩散系数——等折射率薄层测量方法  

Measuring the diffusion coefficient of liquids by capillary imaging method: equivalent refractive index method

作　　者：李强[1] 普小云[1] 

机构地区：[1]云南大学物理科学技术学院物理系,昆明650091

出　　处：《物理学报》2013年第9期177-183,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号11164033);云南省应用基础研究基金(批准号2011FA006);云南省高校科技创新团队支持计划资助的课题~~

摘　　要：本文提出了一种测量液相扩散系数的新方法.该方法用透明毛细管构成液相扩散池,利用毛细管成像法特有的折射率空间分辨测量能力,通过直接观察和记录扩散介质的等折射率薄层在毛细管中的移动规律,基于扩散过程遵循的Fick第二定律计算出液相扩散系数.在25C下研究了丙三醇和纯水间的扩散过程,扩散系数的测量值与全息干涉法的文献报道值之间的相对误差为4.47%,论文同时分析了折射率测量精度和毛细管管壁黏滞力对扩散系数的影响.用毛细管成像法测量液相扩散系数具有样品需要量少、测量速度快、系统稳定性好的特点。A novel method for measuring the diffusion coefficient of liquids is introduced in this paper. A transparency capillary is used as both diffusive pool and imaging element, spatially resolving ability of the capillary in measuring refractive index of liquid is utilized to observe and record diffusive process directly, diffusion coefficient of liquid is calculated based on Fick second law and acquired experimental data. With the new method, the diffusive process of pure glycerol in water at 25 C is investigated, the obtained diffusion coefficient is 0.898 × 10 5 cm 2 /s, which is of a relative error 4.47% compared with the literature value measured by the holographic interference. The influence of measurement accuracy of refractive index and capillary viscosity on measuring result is also analyzed. The method is characterized by micro-quantity sample required, faster measurement and better stability, which opens a new way to measure diffusion coefficient of liquid medium.

关 键 词：扩散系数 液体折射率 毛细管成像法 

分 类 号：O436.2[机械工程—光学工程]