中文摘要：

声镊子能够操控和筛选细胞等粒子，使之在参数设定的轨道上排列。不管粒子的形状、尺寸、电性如何，声镊子都可以对其进行有效的筛选和操控。由于声镊子输出能量密度远小于光镊子，在对细胞操控过程中，不会对活体细胞造成伤害，具有构造简单、体积小、制作成本低、多功能等特性，并且非接触式的操作使声镊子具有很好的生物相容性，这些优点使得声镊子在材料、生物、医疗等领域具有重要的研究意义。采用20 MHz 的叉指换能器，对水溶性硅油液滴和荧光聚苯乙烯粒子进行操控，分别研究了行波场和驻波场声表面波对水溶硅油液滴和聚苯乙烯粒子的作用，成功地使聚苯乙烯粒子在设定的波节位置排列成行。观察到了四象限的声流图案，验证了瑞利声流的存在。进而，用扭称实验测出压电晶片铌酸锂表面产生的声流对平板材料的作用力大小，得到了声流作用力与声强大小的关系。

英文摘要：

Acoustic tweezers can manipulate and filter particles like cells.Under the control of acoustic tweezers, particles can be arranged in the orbits when their parameters are set.Acoustic tweezers can select and manipulate cells and particles effectively,regardless of their shapes,sizes or electrical properties.As the energy density of acoustic tweezersis being far lower than that of optical tweezers,it will not hurt living cells,and acoustic tweezers have the advantages of simple structure,small volume,low costs,multi-functional and non-contact operation characters which gives acoustic tweezers good biocompatibility.These advantages will ensure acoustic tweezers play an important role in materials,biology,medical research and other fields.In this paper,we developed the interdigital transducers of 20 MHz to manipulate water soluble silicone oil droplets and fluorescence polystyrene particles.We studied the function of surface plane wave and surface standing wave on the droplets and the polystyrene particles re-spectively.As a result,the polystyrene particles are successfully trapped in the nodal positions,and the four-quadrant acoustic streaming patterns are observed,verifying the existence of Rayleigh acoustic streaming.Furthermore,we measured the force of acoustic streaming acting on the plate and concluded the relationship between the function ofnbsp;acoustic streaming and the power of signal applied to the acoustic tweezers.