声波对球形粒子的声辐射力研究

发布时间：2018-09-19 06:06

【摘要】：随着现代科技的发展,对微纳米级粒子的无接触式操控的需求越来越迫切,尤其是在生物医学和工业领域。声场中的微小粒子会受到其声辐射力的作用,在特定条件下粒子将会被稳定在声场的特定的空间位置,利用声辐射力可以实现声场对微粒的操作和捕获作用。因此利用声场的梯度和微粒间的相互作用可以实现细胞筛选、药物输送、声悬浮等应用,这在生物医学及材料科学中有着重要的研究意义。本论文主要利用两种理论方法对声波作用于球形粒子的声辐射力的特性进行了研究。在第一章中,回顾了与声辐射力有关的理论研究背景和实际应用,介绍了近期有关声辐射力的研究内容和进展,并概述了本文研究工作的主要内容。第二章主要介绍了几何声学近似的方法,通过此方法对微球在高斯声场中声辐射力特性进行了研究,同时考虑了粒子中的声衰减对二维声辐射力的影响,分析了声势阱现象产生的条件,并讨论了粒子初始位置,粒子大小等对声辐射力大小的影响。结果表明,当粒子处于某些特定位置可以受到声阱力作用,考虑衰减不会对声学镊子的捕获性质产生影响,仅对其捕获能力产生影响。第三章中,在几何声学理论下,提出了双层球所受辐射力的模型,仿真计算详细讨论了双层球的球壳厚度各层介质的声学性质对声势阱的位置和大小产生的影响,给出了更加贴合实际实验应用需要的声辐射力理论模型。在第四章,基于几何声学近似的方法,提出了微球在球面聚焦声场中所受声辐射力的模型,分析了聚焦声场的参数对球形粒子声辐射力的影响。结果表明常规球面聚焦声源对粒子球同样有三维捕获作用。第五章主要介绍了声场的散射理论,分析讨论了各种边界条件对声场的散射作用,同时本章利用有限级数展开的方法,将高斯聚焦声波按照球函数展开,详细推导了声散射理论下,高斯声波对球型粒子的声辐射力函数,为研究复杂声波波形的辐射力奠定基础。第六章提出并研究了散射理论中高斯驻波场及类高斯驻波场的声辐射力函数,分析了高斯驻波场及类高斯驻波场中球形粒子所受的声辐射力特性,同时说明了高斯驻波场对粒子的操控作用,此结论也与前人的实验结果相符。第七章对全文进行了总结及展望。本文系统地研究了球形粒子在声场中的声辐射力特性,建立了各种不同声场中声辐射力模型,进行了理论推导和数值分析,本研究对工业上声辐射力无损操控及医学上的细胞和药物筛选有着重要的理论指导作用。
[Abstract]:With the development of modern science and technology, the demand for non-contact manipulation of microparticles is becoming more and more urgent, especially in biomedical and industrial fields. The tiny particles in the sound field will be affected by their sound radiation force, and under certain conditions, the particles will be stabilized in the special space of the sound field. Using the sound radiation force, the operation and capture of the particles can be realized. Therefore, the use of the gradient of sound field and the interaction between particles can realize cell screening, drug delivery, acoustic suspension and other applications, which has an important research significance in biomedical and material science. In this paper, two theoretical methods are used to study the characteristics of acoustic radiation force acting on spherical particles. In the first chapter, the theoretical research background and practical application related to acoustic radiation force are reviewed, the recent research contents and progress of acoustic radiation force are introduced, and the main work of this paper is summarized. In the second chapter, the geometric acoustics approximation method is introduced, by which the acoustic radiation force characteristics of microspheres in Gao Si sound field are studied, and the influence of sound attenuation in particles on two-dimensional acoustic radiation force is considered. The conditions under which the sound well phenomenon is produced are analyzed, and the effects of particle initial position and particle size on the sound radiation force are discussed. The results show that when the particle is in some specific position it can be subjected to the action of acoustic trap force and considering attenuation does not affect the trapping property of acoustic tweezers but only its capture ability. In chapter 3, based on the geometric acoustics theory, a model of radiation force on a double-layer sphere is proposed. The effects of the acoustic properties of the spherical shell thickness of the double-layer sphere on the position and size of the sound potential well are discussed in detail. The theoretical model of acoustic radiation force which is more suitable for practical application is given. In chapter 4, based on the method of geometric acoustic approximation, a model of sound radiation force on microspheres in spherical focusing sound field is proposed, and the influence of the parameters of focusing sound field on the sound radiation force of spherical particles is analyzed. The results show that the conventional spherical focusing sound source can also capture the particle sphere in three dimensions. In the fifth chapter, the scattering theory of sound field is introduced, and the scattering effect of various boundary conditions on sound field is analyzed and discussed. At the same time, by using the method of finite series expansion, Gao Si focused sound wave is expanded according to spherical function. In this paper, the sound radiation force function of Gao Si acoustic wave on spherical particles is deduced in detail, which lays a foundation for studying the radiation force of complex acoustic wave. In the sixth chapter, the acoustic radiation force functions of Gao Si standing wave field and Gao Si like standing wave field in scattering theory are proposed and studied, and the characteristics of sound radiation force of spherical particles in Gao Si standing wave field and Gao Si like standing wave field are analyzed. At the same time, the control effect of Gao Si standing wave field on particles is explained, and this conclusion is in agreement with the previous experimental results. Chapter seven summarizes and prospects the full text. In this paper, the characteristics of sound radiation force of spherical particles in sound field are systematically studied, and various models of sound radiation force in different sound fields are established, and the theoretical derivation and numerical analysis are carried out. This study has important theoretical guidance for industrial sound radiation nondestructive manipulation and medical cell and drug screening.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O422

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