Abstract

It is shown that the suppression of electromagnetic noise by at least 10 dB compared to the amplitude of the acoustic signal is of key importance in the measurement of the electric characteristics of liquid samples using normal acoustic waves, which can be achieved by placing the test sample in the gap between interdigital transducers on a plate and/or electronic suppression of interference in the measuring device. As distinct from the acoustoelectronic interaction of bulk and surface waves in piezoelectric semiconductors, the dependence of the absorption of Lamb modes in piezoelectric plates on conductivity σ of the liquid load is asymmetric. In this case, the selective measurement of conductivity σ is difficult due to the cross-sensitivity of waves to dielectric ε_l and viscous η properties of the liquid. It is found that σ ranges from 0 to 10 S/m under minor variations in parameters ε and η, the sensitivity of normal waves amounts to 0.4 dB/(S/m) with respect to amplitude and 4.4°/(S/m) with respect to phase, and the required sample volume is no greater than 200–500 µL.

中文翻译：

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使用正声波检测导电液体电特性的具体特点

摘要

结果表明，与声信号的幅度相比，电磁噪声抑制至少 10 dB 对于使用正常声波测量液体样品的电特性至关重要，这可以通过放置测试样品来实现在板上的叉指传感器之间的间隙和/或测量设备中的电子干扰抑制。与压电半导体中体波和表面波的声电子相互作用不同，压电板中 Lamb 模式的吸收对液体负载的电导率 σ 的依赖性是不对称的。_{在这种情况下，由于波对电介质 ε l}的交叉敏感性，电导率 σ 的选择性测量很困难和液体的粘性 η 特性。发现在参数 ε 和 η 的微小变化下，σ 的范围从 0 到 10 S/m，法向波的灵敏度为 0.4 dB/(S/m) 相对于幅度和 4.4°/(S/m)相对于相位，所需的样品体积不大于 200–500 µL。