Ultrasonic wave micro manipulation of micro particle and its application on measurement

当充气微泡等小颗粒进入超声波场时，微颗粒与超声波相互作用，气泡形成聚集体，形成大量气泡。这些气泡通过超声波被困在周围的液体流动中。本研究提出了利用超声波对微粒进行操纵，并将其应用于高精度测量。本研究的主要成果如下。1)建立了能够模拟微小颗粒在超声波场中运动的数值模型，并对小颗粒的动力学进行了数值模拟。该数值模型以流体力学为基础，能够模拟超声波作用下微粒的精确运动。2)提出了基于一次和二次BJernes力的微泡捕捉法，并展示了其在药物输送系统中的应用。本实验从理论和实验两个方面对超声波捕获微泡的机理进行了探讨。利用两种不同类型的微气泡对频率为5 MHz的超声波进行了实验研究。采用平均直径为20微米和平均直径为1.3微米的两种不同类型的充气微气泡，观察了超声波场中微气泡的动力学特性。3)提出了几种基于声辐射力的微小颗粒操纵方法，并展示了其在高精度测量领域的应用。这些结果为超声波操纵微细颗粒提供了有价值的知识和方法。

When small particles such as gas filled micro bubbles flow into ultrasonic wave field, the micro particles interact with the ultrasonic waves and the bubbles produce aggregations to make large masses of bubbles. Those bubbles are trapped against the surrounding liquid flow by ultrasonic waves. In this research, the micro particles manipulation by ultrasonic waves are proposed and its application to high accuracy measurement is proposed. Main results of this research are as follows. 1) Numerical model which is able to simulate micro particle motion inside the ultrasonic wave fields is developed and the dynamics of small particles are examined numerically. This numerical model is based on fluid dynamics and is able to simulate precise movement of micro particles under ultrasonic waves. 2) Micro bubble trapping based on primary and secondary Bjerknes forces is proposed and its application in the field of drug delivery system is demonstrated. In this experiment, the mechanism of micro bubbles trapping by ultrasonic waves is discussed both theoretically and experimentally. The experiments are carried out using two different types of micro bubbles for the ultrasonic waves with ultrasonic wave frequency 5 MHz. The dynamics of micro bubbles inside ultrasonic wave field are observed using two different types of gas filled micro bubbles with mean diameter 20 micro meter and with mean diameter 1.3 micro meter. 3) Several small particle manipulation methods based on acoustic radiation forces are proposed and some applications in the field of high accuracy measurement are shown. These results give valuable knowledge and methods of micro particle manipulation by ultrasonic waves.