超声波在悬浮液(水)中的吸收

本文研究了低浓度松花粉悬浮液中由于悬浮粒子引起超声波的附加吸收问题。实验上测量声吸收和声速都是采用脉冲干涉仪(当测量吸收时曾以移板法、多次反射法及比较法配合进行),频率范围为3—20Mc,温度范围为20°—80℃,在不同浓度重复进行。针对这样的具体实验条件,根据Epstein提出的理论进行了较严格的计算,并从实验和计算结果的比较中得出几点结论。同时,作者还总结和评述了其他作者关于石松子悬浮液中超声吸收的研究,通过对他们的实验结果和理论值之间的比较,认为他们简单地应用小球或低频极限情况下所得出的理论来解释实

ULTRASONIC ABSORPTION IN AQUEOUS SUSPENSIONS

The ultrasonic absorption in aqueous suspensions (essentially at low concentrations) has been investigated by the pulse interferometric technique. Epstein's theory on this effect is briefly reviewed with the general expressions as well as those of limiting cases for calculating the sound attenuation coefficients derived and discussed corresponding to the actual experimental conditions.Measurements were conducted in aqueous suspensions of the pollen of pinaceae in the frequency range from 3 to 20 Mc at temperatures 20-80℃ for different concentrations. To reduce the measuring errors to a minimum, methods employing both single and multiple pulses, and comparing the pulse height in two troughs one with and the other without the hydrosols, were alternately adopted. Theoretical values based on rigorous formulae and calculated by aid of the electronic digital computer were compared with the experimental ones.Measuring data and corresponding theoretical interpretations based on approximate formulae from some other authors for aqueous suspensions of lycopodium were critically examined. It was pointed out that some of their agreement was fortuitous. The order of magnitude of absorption due to viscosity and scattering under different experimental conditions for the two suspensions was discussed in some length.