Query: 1-3 type composite ultrasonic transducer

title: PMN PT/Epoxy 1 3 composite based ultrasonic transducer for dual modality photoacoustic and ultrasound endoscopy
abstract: Endoscopic dual modality photoacoustic (PA) and ultrasound (US) imaging has the capability of providing morphology and molecular information simultaneously. An ultrasonic transducer was applied for detecting PA signals and performing US imaging which determines the sensitivity and performance of a dual modality PA/US system. In our study, a miniature single element 32 MHz lead magnesium niobate lead titanate (PMN PT) epoxy 1 3 composite based ultrasonic transducer was developed. A miniature endoscopic probe based on this transducer has been fabricated. Using the dual modality PA/US system with a PMN PT/epoxy 1 3 composite based ultrasonic transducer, phantom and in vivo animal studies have been conducted to evaluate the performance. The preliminary results show enhanced bandwidths of the new ultrasonic transducer and improved signal to noise ratio of PA and US images of rat colorectal wall compared with PMN PT and lead zirconate titanate (PZT) composite based ultrasonic transducers.

title: Stress Measurement of a Pressurized Vessel Using Ultrasonic Subsurface Longitudinal Wave With 1 3 Composite Transducers
abstract: This article aims to develop a stress sensing method for a pressurized vessel based on subsurface longitudinal (SSL) waves confined in a specific waveform by using 1 3 composite transducers. Although ultrasonic SSL waves have been commonly utilized for stress sensing, wave excitation under the predefined function using the composite type transmitter is not well studied. In this article, composite type transducers having a wide frequency bandwidth 60% and a predominant thickness mode are utilized to enhance the signal intensity of the SSL wave and the accuracy of the sensor by incorporating a specific toneburst waveform. Finite element analysis demonstrates that the signal intensity of the composite type transducer is up to 45.3% higher than that of a single phase transducer. Pulse echo tests reveal that the frequency bandwidth of the developed transducer reaches up to 60.7% and is, therefore, sufficient 57.0% to transmit and receive Hanning windowed toneburst signals. Results of stress sensing affirm a linear relationship between the time delay of SSL wave and the mechanical stress of a pressurized vessel (0.335 ns/MPa) Accordingly, the regression model is constructed via principal component regression (PCR) under temperature varying condition. PCR has a less significant degree of error (0.62 MPa) compared to that of a typical least square regression (9.49 MPa)

title: Design and Fabrication of Air Based 1 3 Piezoelectric Composite Transducer for Air Coupled Ultrasonic Applications
abstract: The air based 1 3 piezoelectric composite transducers are designed and fabricated in order to solve the acoustic impedance matching problem. Firstly, a finite element model using honeycomb structure as the piezoelectric composite matrix is built to reduce the acoustic impedance of the sensitive element. Three important factors, volume fraction of piezoelectric materials the thickness and the size of the square cross section of piezoelectric column, are examined and verified in simulation. Then, according to the result of simulation, the piezoelectric composites and the air coupled transducers are fabricated. The honeycomb structures of resin are produced by the method of 3D printing technology, with the volume fraction of air being 30% The impedance characteristics and the excitation/reception performance of the air coupled transducers are measured and optimized. Meanwhile, a scanning experiment is carried out to demonstrate the crack detection process in monocrystalline silicon. mode of Lamb waves is excited and collected. The location and size of the defect will be determined by calculating the correlation coefficients of the received signals and reference signals. Finally, a 15 mm x 0.5 mm x 0.5 mm scratch is clearly distinguished.

title: 0.36BiScO3 0.64PbTiO3/Epoxy 1 3 Composite for Ultrasonic Transducer Applications
abstract: In this paper, 0.36BiScO3 0.64PbTiO3 (BSPT) were chosen as piezoelectric materials because of their higher Curie temperature and comparable piezoelectric properties to commercially available lead zirconate titanate polycrystalline ceramics. To get a broader bandwidth, BSPT/epoxy 1 3 composite was fabricated using the dice and fill method to alleviate the acoustic impedance matching problems. The design of the BSPT/epoxy 1 3 composite was guided by W. A. Smith theory to get largest electromechanical coupling coefficients. Finite element simulation was utilized for optimal transducer design. 10 MHz transducers were fabricated using BSPT/epoxy 1 3 composite and monolithic BSPT ceramics with the same fabrication process. Electrical and acoustic properties of the transducers were characterized systematically. The monolithic BSPT ceramics ultrasonic transducer has a center frequency of 10.57 MHz, a electromechanical coupling coefficients of 0.579, and a bandwidth of 24.31% The BSPT/epoxy 1 3 composite ultrasonic transducer has a little lower center frequency (8.93 MHz) a larger effective electromechanical coupling coefficients (0.608) and a broader bandwidth (41.59% The simulation result matched well with measured parameter, which indicate the BSPT/epoxy 1 3 composite is a potential material in application of high frequency and high resolution.

title: High temperature ultrasonic transducers: review
abstract: The problems of development of high temperature ultrasonic transducers for modern science and technology applications are analysed. More than 10 piezoelectric materials suitable for operation at high temperatures are overviewed. It is shown that bismuth titanate based piezoelectric elements are most promisable. Bonding methods of piezoelectric elements to a protector and backing are discussed. Thermosonic gold to gold bonding is most modern and possesses unique features. Our achievements in this field are analysed in the context of world progress. In sol gel and chemical vapour deposition technology bonding and sometimes coupling problems are avoided at all. Design peculiarities of the transducers are reviewed. Commercial sensors in the meanwhile are often characterized with poor performance in extreme conditions. In conclusions recommendations for high temperature ultrasonic transducers design are formulated.

title: A Composite Ultrasonic Transducer with a Fractal Architecture
abstract: To ensure the safe operation of many safety critical structures such as nuclear plants, aircraft and oil pipelines, non destructive imaging is employed using piezoelectric ultrasonic transducers. These sensors typically operate at a single frequency due to the restrictions imposed on its resonant behaviour by the use of a single length scale in its design. To allow these transducers to transmit and receive more complex signals it would seem logical to use a range of length scales in the design so that a wide range of resonating frequencies will result. In this article we derive a mathematical model to predict the dynamics of an ultrasound transducer that achieves this range of length scales by adopting a fractal architecture. In fact, the device is modelled as a graph where the nodes represent segments of the piezoelectric and polymer materials. The electrical and mechanical fields that are contained within this graph are then expressed in terms of a finite element basis. The structure of the resulting discretised equations yields to a renormalisation methodology which is used to derive expressions for the non dimensionalised electrical impedance and the transmission and reception sensitivities. A comparison with a homogenised (standard) design shows some benefits of these fractal designs.

title: Application of ultrasonic transducers for investigation of composite materials
abstract: In this article the developed low frequency contact type ultrasonic transducers and its application are presented. The special scanner carriage, the adjuster, the single holder and tandem holder were manufactured and used in the measurement carried out on the test sample of composite material. The mechanical system enables to support accurately the stable force pressing the transducer to the composite sample. The characteristics of the low frequency transducers in the time and frequency domains are presented. The composite materials such as CFRP and GFRP were investigated using the developed transducers and a contact technique. It was demonstrated that investigated approach enables to detect non uniformities in composite materials.

title: Phantom evaluation of stacked type dual frequency 1 3 composite transducers: A feasibility study on intracavitary acoustic angiography.
abstract: In this paper, we present phantom evaluation results of a stacked type dual frequency 1 3 piezoelectric composite transducer as a feasibility study for intracavitary acoustic angiography. Our previous design (6.5/30 MHz PMN PT single crystal transducer) for intravascular contrast ultrasound imaging exhibited a contrast to tissue ratio (CTR) of 12 dB with a penetration depth of 2.5 mm. For improved penetration depth >3 mm) and comparable contrast to tissue ratio >12 dB) we evaluated a lower frequency 2/14 MHz PZT 1 3 composite transducer. Superharmonic imaging performance of this transducer and a detailed characterization of key parameters for acoustic angiography are presented. The 2/14 MHz arrangement demonstrated a 6 dB fractional bandwidth of 56.5% for the transmitter and 41.8% for the receiver, and produced sufficient peak negative pressures >1.5 MPa) at 2 MHz to induce a strong nonlinear harmonic response from microbubble contrast agents. In an in vitro contrast ultrasound study using a tissue mimicking phantom and 200 mm cellulose microvessels, higher harmonic microbubble responses, from the 5th through the 7th harmonics, were detected with a signal to noise ratio of 16 dB. The microvessels were resolved in a two dimensional image with a 6dB axial resolution of 615 mm (5.5 times the wavelength of 14 MHz waves) and a contrast to tissue ratio of 16 dB. This feasibility study, including detailed explanation of phantom evaluation and characterization procedures for key parameters, will be useful for the development of future dual frequency array transducers for intracavitary acoustic angiography.

title: Candle soot nanoparticles polydimethylsiloxane composites for laser ultrasound transducers
abstract: Generation of high power laser ultrasound strongly demands the advanced materials with efficient laser energy absorption, fast thermal diffusion, and large thermoelastic expansion capabilities. In this study, candle soot nanoparticles polydimethylsiloxane (CSNPs PDMS) composite was investigated as the functional layer for an optoacoustic transducer with high energy conversion efficiency. The mean diameter of the collected candle soot carbon nanoparticles is about 45 nm, and the light absorption ratio at 532 nm wavelength is up to 96.24% The prototyped CSNPs PDMS nano composite laser ultrasound transducer was characterized and compared with transducers using Cr PDMS, carbon black (CB) PDMS, and carbon nano fiber (CNFs) PDMS composites, respectively. Energy conversion coefficient and 6 dB frequency bandwidth of the CSNPs PDMS composite laser ultrasound transducer were measured to be 4.41 x 10 3 and 21 MHz, respectively. The unprecedented laser ultrasound transduction performance using CSNPs PDMS nano comp.

title: Design and properties of Gaussian type 1 3 piezoelectric composites
abstract: Here we developed three types of 1 3 connectivity piezoelectric composites consisting of the piezoelectric ceramic rods of gauss variation. The piezoelectric strain constant of the composites exhibits good gauss distribution along the length or radial directions of the composites. The electromechanical and acoustic properties of the piezoelectric composites are greatly improved. The kt value of the Gaussian area array composite is 65.02% which increases by 30% compared with the piezoelectric ceramic. The acoustic impedance value of the composites with Gaussian linear array, Gaussian orthotropic linear array and Gaussian area array is 5.15, 4.74 and 5.93 MRayl, respectively. Our work shows that the ultrasonic transducer which has broad bandwidth, good acoustic impedance matching ability and small acoustic beam side lobe effect can be achieved based on the proposed Gaussian piezoelectric composites.