摘要 :Highlights?A new drive mode for underwater sound generation is proposed.?This mode is made possible by the extremely high transverse piezoelectric properties and Poisson’s ratios of lead-based relaxor single crystals.?The source ...
展开Highlights?A new drive mode for underwater sound generation is proposed.?This mode is made possible by the extremely high transverse piezoelectric properties and Poisson’s ratios of lead-based relaxor single crystals.?The source level of the underwater sound generated by the new mode is comparable to the conventional modes.?Broadband underwater acoustic projector can be designed through multi-mode combination.AbstractNew-generation relaxor-based single crystals exhibit excellent transverse piezoelectric properties and extremely high Poisson’s ratio, making possible a drive mode for underwater sound generation, hereafter referred to as the Transverse Resonance Orthogonal Beam (TROB) mode. Unlike conventional transverse width (CTW) mode in which the resonating direction and the acoustic beam direction are identical, in the TROB mode, the active material is set in resonance in half-wavelength mode in
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Piezoelectric transducers have numerous applications in a wide range of sensing and actuation applications. Such a variety has resulted in continuous research into the design and development of these transducers, including but not...
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Piezoelectric transducers have numerous applications in a wide range of sensing and actuation applications. Such a variety has resulted in continuous research into the design and development of these transducers, including but not limited to their geometry, material and configuration. Among these, cylindrical-shaped piezoelectric PZT transducers with superior features are suitable for various sensor or actuator applications. However, despite their strong potential, they have not been thoroughly investigated and fully established. The aim of this paper is to shed light on various cylindrical piezoelectric PZT transducers, their applications and design configurations. Based on the latest literature, different design configurations such as stepped-thickness cylindrical transducers and their potential application areas will be elaborated on to propose future research trends for introducing new configurations that meet the requirements for biomedical applications, the food industry, as well as other industrial fields.
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Ultrasonic transducer design is focused to maximize performance in specific applications, usually leading to complex design and expensive construction and assembly. With the aim to overcome this drawback, a general-purpose immersi...
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Ultrasonic transducer design is focused to maximize performance in specific applications, usually leading to complex design and expensive construction and assembly. With the aim to overcome this drawback, a general-purpose immersion ultrasonic transducer for pulsed regime applications has been developed. The design of each element of the transducer is described in this paper, wherein materials and geometries for each part have been recommended. A simple theoretical model has been proposed in order to predict the form of the received electric signal in the target transducer. The model is based on the assumption that the piezoelectric element acts as an underdamped oscillator, forced by the acoustic field coming from the propagation medium. Excellent agreement between the experimental measurements and the analytical model is achieved. Electrical impedance measurements reveal negligible differences between the resonance frequency of the active element and that of the assembled transducer. The designed devices have been characterized in water using two identical transducers placed face to face with changeable orientation. The experimental results show a highly linear response and the generation of a collimated acoustic field. The effects of the thickness of the matching layer on the transmission coefficient have been also studied, resulting in a smooth decrease in the received amplitude, which may significantly lower large-scale production costs.
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Classical Langevin-type transducers used in various ultrasound systems to generate high-power ultrasonic vibrations have one operating frequency corresponding to the half-wave resonance in the transducer structure. In this paper, ...
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Classical Langevin-type transducers used in various ultrasound systems to generate high-power ultrasonic vibrations have one operating frequency corresponding to the half-wave resonance in the transducer structure. In this paper, the design of a Langevin-type transducer with four operating frequencies in the range of 20-70 kHz, which correspond to the four flexural modes of transducer's front mass, is proposed and investigated. A transducer prototype was developed and optimized using the finite element method. The transducer was then manufactured and studied experimentally. The results have shown that the transducer provides effective selective excitation of ultrasonic vibrations at the four frequencies.
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Barrel-Stave transducers belong to one of the several classes of Flextensional Transducers, which make use of the flexural vibrations of shells to produce underwater sound. These shells, in turn, are excited by a stack of piezoele...
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Barrel-Stave transducers belong to one of the several classes of Flextensional Transducers, which make use of the flexural vibrations of shells to produce underwater sound. These shells, in turn, are excited by a stack of piezoelectric ceramic rings. The dynamics of barrel-stave transducers are rather complicated and are not easily amenable to analytical treatment. Therefore, design of barrel-stave transducers mostly depend on Finite Element (FE) Methods. In this work, design of a 1 kHz barrel-stave transducer is described. Commercial FE package ATILA is used for modeling the transducer. It is known that the resonance frequencies of this type of transducers depend dominantly on the resonance of the shell. Since the allowable dimensions of shell are decided by the constraints of application, bringing shell frequency down to 1 kHz was achieved by providing several slots on the shell. The driving mechanism consists of a stack of piezoelectric ceramic rings, fitted along the axis of the transducer. Transmitting Voltage Response (TVR) plot of the transducer is generated from the model and it shows a peak value of 130 dB ref μPa/V at 1m, at resonance.
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The area of micro power generation has developed significantly over the last two decades in the field of microelectromechanical systems, self-powered wireless sensor nodes, and mobile platforms. Battery is the main power source of...
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The area of micro power generation has developed significantly over the last two decades in the field of microelectromechanical systems, self-powered wireless sensor nodes, and mobile platforms. Battery is the main power source of such systems but it has some limitations which include finite life time, periodic replacement, and environmental pollutions. Therefore, electrochemical battery system is not a suitable fit for wireless self-powered electronic industry. Energy harvesting through renewable energy such as mechanical vibration can be an attractive alternative solution to replace or widen the lifespan of the traditional battery system. A good number of researches have been conducted on vibration based micro power generation to support the microelectromechanical systems. Electromagnetic, piezoelectric, and electrostatic transducers are used to convert kinetic energy (i.e., mechanical vibration) into electrical energy. A comprehensive literature review has been presented on vibration based micro power generation using two most common transducer mechanisms: electromagnetic and piezoelectric transduction systems. (C) 2015 Elsevier Ltd. All rights reserved.
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We propose a formal definition for the general notion of stochastic transducer, called stochastic λ-transducer. Our definition is designed with two objectives in mind: (ⅰ) to extend naturally the established notion of stochastic...
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We propose a formal definition for the general notion of stochastic transducer, called stochastic λ-transducer. Our definition is designed with two objectives in mind: (ⅰ) to extend naturally the established notion of stochastic automaton with output- as defined in the classic books of [A. Paz, Introduction to Probabilistic Automata, Academic Press, New York and London, 1971; P. Starke, Abstract Automata, North-Holland, Academic Press, 1972.] - by permitting pairs of input-output words of different lengths; (ⅱ) to be compatible with the more general notion of weighted transducer so that one can apply tools of weighted transducers to address certain computational problems involving stochastic transducers. The new transducers can be used to model stochastic input-output processes that cannot be modelled using classical stochastic automata with output.
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Many types of medical ultrasound transducers are used in clinical practice. They operate at different center frequencies, have different physical dimensions, footprints, and shapes, and provide different image formats. However, li...
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Many types of medical ultrasound transducers are used in clinical practice. They operate at different center frequencies, have different physical dimensions, footprints, and shapes, and provide different image formats. However, little information is available about which transducers are most appropriate for a given application, and the purpose of this article is to address this deficiency. Specifically, the relationship between the transducer, imaging format, and clinical applications is discussed, and systematic selection criteria that allow matching of transducers to specific clinical needs are presented. These criteria include access to and coverage of the region of interest, maximum scan depth, and coverage of essential diagnostic modes required to optimize a patient's diagnosis. Three comprehensive figures organize and summarize the imaging planes, scanning modes, and types of diagnostic transducers to facilitate their selection in clinical diagnosis.
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The sensitive membrane of capacitive ultrasonic transducers is quite crucial for their performances, which can affect sensitivity, bandwidth, acoustic impedance, etc. In this study, an air-coupled capacitive ultrasonic transducer ...
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The sensitive membrane of capacitive ultrasonic transducers is quite crucial for their performances, which can affect sensitivity, bandwidth, acoustic impedance, etc. In this study, an air-coupled capacitive ultrasonic transducer array is proposed with sensitive materials of MXenes. The air-coupled ultrasonic array with a Ti3C2Tx diaphragm is designed and fabricated. The array is
$4\times4$
in size, with a membrane radius of 1 mm and a central frequency of 112.5 kHz. The simulation and experiments of the array are carried out to analyze the effect of the transducer characteristics by direct current (dc) bias voltages and alternating current (ac) excitation. The transmitting and receiving performance of the designed array are tested, and the results demonstrate that the array has outstanding sound pressure level (SPL) and receiving sensitivity. The feasibility of using Ti3C2Tx as a capacitive ultrasonic transducer diaphragm is indicated in this article, which expands the potential applications in acoustic measurement, detection, and imaging.
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This paper describes the development of a miniaturized high-frequency linear array that can be integrated within a core biopsy needle to improve tissue sampling accuracy during breast cancer biopsy procedures. The 64-element linea...
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This paper describes the development of a miniaturized high-frequency linear array that can be integrated within a core biopsy needle to improve tissue sampling accuracy during breast cancer biopsy procedures. The 64-element linear array has an element width of , kerf width of , element length of 1 mm, and element thickness of . The 2–2 array composite was fabricated using deep reactive ion etching of lead magnesium niobate-lead titanate (PMN-PT) single crystal material. The array composite fabrication process as well as a novel high-density electrical interconnect solution are presented and discussed. Array performance measurements show that the array had a center frequency and fractional bandwidth ( ) of 59.1 MHz and 29.4%, respectively. Insertion loss and adjacent element crosstalk at the center frequency were and , respectively. A B-mode image of a tungsten wire target phantom was captured using a synthetic aperture imaging system and the imaging test results demonstrate axial and lateral resolutions of 33.2 and , respectively.
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