Design And Experimental Study Of Probe-Type Nanowire Manipulation System Based On Acoustic Streaming

Nanowire-based micro/nanoscale devices/systems have played an important role in electronic information,communication,robotics and other fields.Therefore,research on nanowire manipulation methods to achieve simple and controllable operations on nanowires is of great significance to promote the further development of nanowire micro/nanoscale devices/systems.In this paper,the simulation analysis of the manipulation method of the probe-type nanowire manipulation system based on the acoustic streaming,the design of the ultrasonic vibration system and the related experimental research were studied.The main work of the paper is summarized as follows:The acoustic streaming was simulated and calculated with the spatial gradient of the Reynolds stress and the time-averaged second order sound pressure as the driving force.The effects of various parameters in the model on the acoustic streaming were analyzed.It is concluded that the acoustic streaming generated by the elliptical vibration with the long axis twice the short axis in the YZ plane is the optimal acoustic streaming distribution for manipulating nanowires.In addition,under the condition of ensuring that the Y-direction amplitude is twice the Z-direction amplitude,changing the magnitude of the Y-direction and Z-direction amplitude at the same time can change the flow velocity of the acoustic streaming without changing the acoustic streaming distribution.In order to generate the acoustic streaming required for nanowire manipulation,a dual-transducer parallel mechanism vibration system was designed.By setting a vibration transmission rod on the front cover of one of the transducers,the longitudinal vibration of the transducer was converted into the transverse vibration at the end of the vibration transmission rod.When the transducers are connected in parallel,an elliptical vibration in the vertical plane can be generated at the end vertex of the worktable.According to the electromechanical equivalent circuit method and the nodal surface method,the geometric dimensions of the components of the two transducers were determined when the resonant frequency is 100 k Hz.Based on the finite element method,dynamic simulation and optimization of the transducer and its parallel mechanism were carried out,including modal analysis,size optimization,frequency response analysis,and ellipse trajectory fitting.The resonant frequencies of the optimized transducer are 100.08 k Hz and 100.25 k Hz,respectively,and there is no parasitic vibration mode near the operating frequency.The size and shape of the elliptical vibration track can be controlled by adjusting the amplitude and phase of the excitation voltage of the two transducers.The impedance and vibration performance of the transducer vibration system were tested,and the relationship between the output amplitude of the parallel mechanism and the excitation voltage was calibrated.According to the experimental data,the operating frequency of the parallel mechanism is selected as 96 k Hz,and the error from the design frequency is 4%.A probe-type nanowire manipulation system was built.By adjusting the positioning platforms on both sides to change the relative position between the probe and the nanowire,the capture,transport and release of Ag nanowires were realized on both sides of the probe.Experimental results show that the system can manipulate nanowires of different sizes and positions.