激光衍射法测量表面张力和表面压

实验上实现了低频液体表面波的激光衍射,提出了激光衍射法测量液体表面张力和表面压。当激光斜入射到几百赫兹液体表面波上,观察到反射光形成稳定的、清晰的衍射光斑。理论上导出了衍射光斑的角宽度和表面波波长的解析关系,实验上验证了液体表面波的色散关系,计算了蒸馏水的表面张力和蒸馏水中加入不溶性表面活性剂———“苯”单分子膜的表面压。根据其机理,建立起一种实时、非接触测量液体表面张力和表面压的实用方法。

Probing Surface Tension and Surface Pressure by Laser Diffraction

Laser diffraction from liquid surface waves at low-frequency was experimentally realized,A laser diffraction technique for measuring surface tension and surface pressure was designed.When laser falls on the liquid surface wave of several hundreds in angle,in the experiment steady and visible diffraction patterns were obtained.The analytic expression of a angle width of the diffraction fringe range and wavelength of surface waves was derived theoretically,subsequently,the theory of dispersion relations is well consistent with the experimental data,surface tension of distilled water and surface pressure of insoluble surface film of Benzene are measured carefully.Based on the principle of this experiment,a new method for measurement of liquid surface tension and surface pressure is built in a real time and non-destructive way.