“相位驻波”法测量液体的表面张力系数  

Measuring surface tension coefficient of liquid by “phase standing wave” method

作　　者：沙金巧 虞一青 杨俊义[2] 范君柳[1] Sha Jin-Qiao;Yu Yi-Qing;Yang Jun-Yi;Fan Jun-Liu(School of Physical Science and Technology,Suzhou University of Science and Technology,Suzhou 215009,China;School of Physical Science and Technology,Soochow University,Suzhou 215006,China)

机构地区：[1]苏州科技大学物理科学与技术学院,苏州215009 [2]苏州大学物理科学与技术学院,苏州215006

出　　处：《物理学报》2022年第22期242-248,共7页Acta Physica Sinica

基　　金：“十四五”江苏省重点学科建设经费(批准号:2021135)资助的课题。

摘　　要：液体表面张力系数测量技术中,非接触法测量具有快速、无损和简单实用等优点.本文设计了一种非接触式测量透明液体表面张力系数的新方法,发现了一种特殊的“自干涉”现象,并提出“相位驻波”理论解释了该现象产生的原因.通过一个频率可调的振动源激发液体表面波,利用普通光源或激光光源斜入射至液面,经过液面下方的漫反射面反射后,光波携带第一次表面波相位信息与表面波再次相遇,使两次相位余弦波产生了驻波形式的相位分布,从而在远场观察到明暗相间且非常稳定的“自干涉”条纹.通过对图像分析处理,实现条纹间距的自动测量,根据表面波的色散关系,自动准确地获得液体的表面张力系数,该方法可广泛应用于液体表面张力系数的精确测量.The surface tension of liquid is an important parameter to characterize the properties of liquid. The noncontact method of measuring the surface tension coefficient of liquid has the advantages of being fast, nondestructive, simple and practical. A new non-contact method of measuring the surface tension coefficient of transparent liquid based on the theory of light propagation is developed, and a special phenomenon of “selfinterference” is discovered. The “Phase Standing Wave” theory is proposed to explain the phenomenon.The surface wave of the liquid is excited by a frequency-adjustable vibration source(oscillator), and it propagates dynamically in the form of oscillator and cosine wave. When the white light source or laser is incident on the liquid surface obliquely, the phase distribution(cosine-like wave) generated by the light wave carrying the surface wave is first incident on the white paper which is located at the bottom of liquid, and the oscillator will also form the oscillator shadow on the white paper. The phase distribution of the light wave on the white paper spreads around dynamically in the form of cosine wave centering on the oscillator shadow.After diffuse reflection from the white paper, part of the diffuse reflection light in the observation direction carries the dynamic phase generated by the surface wave the first time back to the liquid surface and meets the surface wave again. After the light wave passes through the surface, it carries the phase generated by the surface wave the second time, that is, the superposition of two surface waves occurs in the phase of the light wave. In the phase of the light wave, the phase wave of the oscillator will propagate in the direction of the oscillator shadow, and the phase wave of the oscillator shadow will propagate in the direction of the oscillator.According to the conditions of forming standing waves, two surface waves propagating in the opposite directions can form standing waves, so the phase standing waves can exist only within a relati

关 键 词：自干涉 相位驻波 表面张力系数 

分 类 号：O552.421[理学—热学与物质分子运动论]