激光衍射法测量液体表面张力的改进

Improvement on Liquid Surface Tension Measured by Laser Diffraction

描述了一种在液体表面生成已知频率的毛细波的方法,采用激光衍射法测量液体表面张力系数.毛细波的传播和色散与表面张力有关.根据该原理,我们采用光纤光谱法,配合导轨采集衍射图样数据进行计算,得出在20℃下蒸馏水的表面张力系数,与标准值的误差约为3%.我们还将光纤光谱法用于测量牛奶表面张力系数与放置时间的关系,与采用拉脱法得到的变化趋势有些类似.

A method of generating capillary waves with certain frequency on the surface of liquids is described.The propagation and dispersion of capillary waves are related to the surface tension.Based on this principal,the coefficient of surface tension was measured in this experiment using optical fiber spectrometer,which is mounted on an automatic guide.The coefficient of surface tension of water at 20℃ by capillary laser diffraction is measured in this experiment.The deviation between the measured result and standard value is about 3%.This method was also used to measure the surface tension coefficient of milk changing with different exposure time,and it shows a similar result to that used tearing-off method.