Compressional-Wave Effects in the Operation of a Quartz Crystal Microbalance in Liquids:Dependence on Overtone Order
Compressional-Wave Effects in the Operation of a Quartz Crystal Microbalance in Liquids:Dependence on Overtone Order
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DOI：
10.3390/s20092535
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发表时间：
2020-05-01
期刊：
影响因子：
3.9
通讯作者：
Johannsmann, Diethelm
中科院分区：
文献类型：
--
作者：
Kowarsch, Robert;Suhak, Yuriy;Johannsmann, Diethelm
石英晶体微天平（QCM）在液体中的操作受到小的弯曲混合物的厚度剪切变形的困扰。谐振器表面不仅在横向方向上移动，而且沿着表面法线移动，从而将压缩波发射到液体中。使用一个简单的分析模型和激光多普勒测振仪，我们表明，弯曲外加剂的基本模式比上的泛音更强。运动的正常振幅约为基模横向运动的1%。这个比率在泛音上下降了两倍。在实验中观察到对泛音阶的类似依赖性，其中谐振器浸入液体中并且面对相对的平面壁，其距离变化。在一定距离上会出现驻波压缩波。这些振幅在泛音上比在基模上小。研究结果可以合理化的张量形式的小负载近似。
The operation of the quartz crystal microbalance (QCM) in liquids is plagued by small flexural admixtures to the thickness-shear deformation. The resonator surface moves not only in the transverse direction, but also along the surface normal, thereby emitting compressional waves into the liquid. Using a simple analytical model and laser Doppler vibrometry, we show that the flexural admixtures are stronger on the fundamental mode than on the overtones. The normal amplitude of motion amounts to about 1% of the transverse motion on the fundamental mode. This ratio drops by a factor of two on the overtones. A similar dependence on overtone order is observed in experiments, where the resonator is immersed in a liquid and faces an opposite planar wall, the distance of which varies. Standing compressional waves occur at certain distances. The amplitudes of these are smaller on the overtones than on the fundamental mode. The findings can be rationalized with the tensor form of the small-load approximation.