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Characterization and optimization of piezoelectric single crystal/polymer composites for high performance ultrasonic transducers

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Characterization and optimization of piezoelectric single cr...

High-resolution photoacoustic microscope for rat brain imaging in vivo

2011年全国压电和声波理论及器件应用研讨会

作者： Zhengbin Wu 1 Shenzhen Institute of Advanced Integration Technology,Chinese Academy of Sciences/The Chinese University of Hong Kong,Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055 2 Harbin Institute of Technology Shenzhen Graduate School,Shenzhen 518055 3 Institute of Biomedical and Health Engineering,Shenzhen Institutes of Advanced Technology.Chinese Academy of Sciences,Shenzhen 518055 ,

＜正＞As a valid information carrier,ultrasound is widely used in the areas of biomedical imaging,diagnosis,and therapy;industrial non-destructive testing;and underwater sonar,as well as for various topics in remote sensing across a broad range of industrial and individual *** the practical applications,a sufficiently broadband frequency is normally required from the ultrasonic transducers in the whole system,which is especially crucial for non-linear characterization and high resolution *** the past decades,piezoelectric composites comprising piezoelectric single crystal and passive polymer materials have attracted the attention of researchers and industrialists. These have lower acoustic impedance,higher electromechanical coupling coefficient,and broader frequency bandwidth,which are the ideal candidate to manufacture high performance ultrasonic *** to low damped piezoelectric crystal materials such as PZT and PMN-PT,accurate characterization of these lossy piezoelectric composite materials is fundamentally required so that the resulted effects on the structures or devices made from them are then able to be *** the same time,further optimization of the frequency bandwidth of these novel piezoelectric single crystal composite materials is highly *** this talk,we will report the research progress in these *** theoretical and experimental results of novel precise characterization and optimization methods for piezoelectric single crystal composites will be presented,which are promising for their applications in high performance ultrasound transducers.

关键词： Piezoelectric single crystal/polymer composite Characterisation Optimisation ultrasonic transducers

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Chinese Optics Letters 2010年第6期8卷 609-611页

作者：杨孝全蔡鑫 Konstantin Maslov 汪立宏骆清铭 Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and Technology Optical Imaging Laboratory Department of Biomedical EngineeringWashington University in Saint LouisSaint Louis63130-4899USA

A reflection-mode photoacoustic microscope（PAM） for rat brain imaging in vivo is constructed.A pulsed laser is used as an excitation source,and a focused ultrasound transducer is adopted to collect the photoacoustic *** scanning is applied to acquire three-dimensional（3D） *** obtained measurements of the lateral and axial resolutions of the microscope are 45 and 15μm,*** imaging depth in the chicken breast tissue is 3.1 mm at a signal-to-noise ratio（SNR） of 20 dB without any signal *** imaging speed is 30 A-line/*** results in vivo demonstrate the capability of 3D imaging of the brain vessels of the rat after removing the skull.

关键词： Acoustic microscopes Laser excitation Photoacoustic effect Photoacoustic microscopy Pulsed laser applications Pulsed lasers Signal to noise ratio ultrasonic transducers

Photoacoustic Doppler flowmetry of carbon particles flow using an autocorrelation method

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Optoelectronics Letters 2014年第6期10卷 467-469页

作者：卢涛 College of Electrical Engineering Henan University of Technology

In order to measure the axial flowing velocity of carbon particle suspension with particle diameter of tens of micrometers, the photoacoustic Doppler(PAD) frequency shift is calculated based on a series of individual A scans using an autocorrelation method. A 532 nm pulsed laser with repetition rate of 20 Hz is used as a pumping source to generate photoacoustic signal. The photoacoustic signals are detected using a focused piezoelectric(PZT) ultrasound transducer with central frequency of 5 MHz. The suspension of carbon particles is driven by a syringe pump. The complex photoacoustic signal is calculated by the Hilbert transformation from time-domain photoacoustic signal, and then it is autocorrelated to calculate the Doppler frequency shift. The photoacoustic Doppler frequency shift is calculated by averaging the autocorrelation results of some individual A scans. The advantage of the autocorrelation method is that the time delay in autocorrelation can be defined by user, and the requirement of high pulse repetition rate is avoided. The feasibility of the proposed autocorrelation method is preliminarily demonstrated by quantifying the motion of a carbon particle suspension with flow velocity from 5 mm/s to 60 mm/s. The experimental results show that there is an approximately linear relation between the autocorrelation result and the setting velocity.

关键词： Autocorrelation Carbon Doppler effect Flow velocity Frequency shift keying Mathematical transformations Optical pumping Pulse repetition rate Time delay Time domain analysis ultrasonic transducers

Transverse flowmetry of carbon particles based on photoacoustic Doppler standard deviation using an auto-correlation method

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Optoelectronics Letters 2015年第3期11卷 226-228页

作者：卢涛孙丽君 College of Electrical Engineering Henan University of Technology

In order to measure the flow velocity of carbon particle suspension perpendicular to the receiving axis of ultrasound transducer, the standard deviation of photoacoustic Doppler frequency spectrum is used to estimate the bandwidth broadening, and the spectrum standard deviation is calculated by an auto-correlation method. A 532 nm pulsed laser with the repetition rate of 20 Hz is used as a pumping source to generate photoacoustic signal. The photoacoustic signals are detected using a focused PZT ultrasound transducer with the central frequency of 10 MHz. The suspension of carbon particles is driven by a syringe pump. The complex photoacoustic signal is calculated by Hilbert transformation from time domain signal before auto-correlation. The standard deviation of the Doppler bandwidth broadening is calculated by averaging the auto-correlation results of several individual A scans. The feasibility of the proposed method is demonstrated by measuring the spectrum standard deviation of the transversal carbon particle flow from 5.0 mm/s to 8.4 mrn/s. The experimental results show that the auto-correlation result is approximately linearly distributed within the measuring range.

关键词： Bandwidth Carbon Correlation methods Flow velocity Mathematical transformations Optical pumping Pumping (laser) Statistics Time domain analysis transducers ultrasonic propagation ultrasonic scattering ultrasonic transducers

CONTROL OF ROBOT DRIVEN BY MULTIPLE ultrasonic MOTORS BASED ON ROBUST PARAMETER DESIGN

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Transactions of Nanjing University of Aeronautics and Astronautics 2009年第4期26卷 243-250页

作者：孙志峻帅双辉黄卫清南京航空航天大学机电学院第二炮兵军代室南京航空航天大学精密驱动研究所

An ultrasonic motor （USM） is difficlt to be mathematically described because of its complex energy conversion and nonlinear parameters from increasing temperature and changing operating conditions. To achieve good performance of a three-joint robot directly driven by USM, according to the operating characteristics of USM, a new position-velocity feedback control strategy is proposed. In the control strategy, there are a total of 18 controller gains to he tuned. Through a series of ＂Design of Experiments＂ by the robust parameter design, an optimal and robust set of proportional integral derivative （PID） controller gains is obtained. Results show that the control strategy can achieve the best performance of the robot and the robust parameter design is effective and convenient to USMs.

关键词： ultrasonic transducers robust control proportional integral derivative (PID) control position-veloci-ty feedback