【作者】 蒋鹏；

【导师】 A.P.Baker；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2013， 硕士

【摘要】 近年来，在天然晶体的电子能带理论启发下，人们对周期复合材料或结构中的经典波的传播进行了很多研究。存在有弹性波禁带的周期复合材料，即为声子晶体，由于其禁带、通带、缺陷带的奇妙特性，可以用调控声场和制备各种新颖的器件。声操控是利用声波携带动量和能量，能够对处于声场中的物体产生力作用并操纵其运动，该技术具有非接触、较好穿透性、无需对微粒进行化学生物修饰等优点，在微粒筛选、化学传感以及微纳制造等领域有着重要作用。然而传统用于操控的声场一般由超声探头等换能器直接产生，只能依靠电子延迟或机械构造改变声场分布，因此只能操控尺寸与波长相当、在焦点附近小范围内的颗粒。本论文主要从声子晶体的特性出发，探讨其在声操控领域的应用。具体而言，设计由不同单胞结构组成的声子晶体条，利用两种条形声子晶体禁带与通带的不同位置，对其组合而成的声子晶体条阵列器件实现了在2.7MHz的波导，我们认为此功能有助于研发声器件的选频、滤波等效应；另外，基于MEMS微纳加工工艺，制备了基于声表面波叉指换能器的微流控芯片，并利用该芯片实现了对超声造影剂微泡的一维排列及空化效应，该技术具有精确定位操控、微型化、无损伤等优点；论文的最后一步工作是将声子晶体板与声操控结合，探讨了利用声子晶体板对微粒的排列效应，该工作主要是利用刻有周期性栅格的声子晶体板在共振频率时可以激发很强的周期局域梯度场，可以对声子晶体板表面的微粒进行捕获与周期排列，由于该系统是基于微纳加工工艺集成，其在微操控领域具有潜在应用价值。更多还原

【Abstract】 Recently, inspired by the electronics band theory of natural crystals, a lot workshave been done on wave propagation of periodic composite materials or structures.Generally, those periodic materials or structures with elastic waves stop bands arephononic crystals. Due to the properties like stop bands, conductive bands and defectszones, phononic crystals can be used in various novel devices. Acoustic manipulation, amicro-scale manipulation technique achieved by applying acoustic waves, has someadvantages including non-contact, penetrability and versatility, without any biochemicaldecorations to particles. However, the acoustic fields generated by conventional systemscannot be redesigned easily, nor can the corresponding acoustic radiation forces bemodulated efficiently. Moreover, any particle with size much smaller than wavelengthcannot be manipulated.This essay focus on the properties of phononic crystals and its applications inacoustic manipulation. Specifically, a novel waveguide structure based onmulti-scattering has been developed. The band structures and transmissions of twonovel phononic crystal strips have been studied. The wave guide of elastic wave withfrequency of2.7MHz can be realized with the combination of two phononic crystalstrips. In addition, fabrication of surface acoustic wave devices based on interdigitaltransducers have been studied, which have been used for1D patterning of microbubblesand cavitation. We also have studied the possibility of acoustic aligning microparticlesnear the surface with the phononic crystal slab, which can excite strong local gradientfields. We have experimentally realized the aligning of micro-particles by a PCS. Sincethe manipulation system is fabricated on a chip, it can be easily integrated with MEMStechnology and combined with other micro-processing technology. We believe thistechnique can be developed to meet the needs of non-contact and precise manipulationof cells and biological particles.更多还原