Bennès J, Alzuaga S, Chabé P, Morain G, Chérioux F, Manceau J-F, Bastien F
FEMTO-ST Institute, LPMO Department CNRS-UMR 6174 32, Besançon cedex, France.
Ultrasonics. 2006 Dec 22;44 Suppl 1:e497-502. doi: 10.1016/j.ultras.2006.05.029. Epub 2006 Jun 5.
Liquids handling is an important issue in biomedical analysis. Two different devices for acoustic manipulation of droplets have already been tested. The first one, more classical, uses a high frequency travelling wave and acoustic streaming. The second one uses low frequency flexural standing waves in a plate. This means of liquid handling is original and easy to implement but the physical principle is not obvious. In order to understand more precisely the phenomena involved we present new observations on droplet displacement between two planes and on the behaviour of a droplet on an inclined vibrating plane with this method. The physical principle involved is discussed. The common acoustic radiation pressure formulation is expressed via the non-linear theory of sound propagation, but in our case the acoustic wavelength is much smaller than the height of a water droplet. To get a better understanding of the phenomenon, further experiments on the internal liquid flow and behaviour of particles in the droplet have been performed. These will be compared with results obtained with particles in a thin water-filled vibrating glass tube. The general conclusion is that the phenomenon is practical to use for droplet displacement even if its complex mechanism is not completely understood.
液体处理是生物医学分析中的一个重要问题。已经测试了两种用于液滴声学操纵的不同装置。第一种更传统，使用高频行波和声学流。第二种在平板中使用低频弯曲驻波。这种液体处理方式新颖且易于实现，但物理原理并不明显。为了更精确地理解其中涉及的现象，我们用这种方法展示了关于两个平面之间液滴位移以及倾斜振动平面上液滴行为的新观察结果。讨论了其中涉及的物理原理。常见的声辐射压力公式是通过非线性声传播理论来表达的，但在我们的案例中，声波波长比水滴的高度小得多。为了更好地理解这一现象，已经对液滴内部的液体流动和颗粒行为进行了进一步实验。这些实验结果将与在充满水的薄振动玻璃管中颗粒的实验结果进行比较。总体结论是，即使其复杂机制尚未完全理解，该现象对于液滴位移来说也是切实可用的。
