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Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Issue 3 • Date March 2014

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Displaying Results 1 - 21 of 21
  • IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control - Cover

    Publication Year: 2014 , Page(s): c1
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  • IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society - Administrative Committee

    Publication Year: 2014 , Page(s): c2
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  • IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society - Elected Administrative Committee

    Publication Year: 2014 , Page(s): c3
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  • Table of contents

    Publication Year: 2014 , Page(s): i - ii
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  • Information for contributors with multimedia addition

    Publication Year: 2014 , Page(s): 385 - 388
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  • Letters: optically transparent piezoelectric transducer for ultrasonic particle manipulation

    Publication Year: 2014 , Page(s): 389 - 391
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2793 KB) |  | HTML iconHTML  

    We report an optically transparent ultrasonic device, consisting of indium-tin-oxide-coated lithium niobate (LNO), for use in particle manipulation. This device shows good transparency in the visible and near-infrared wavelengths and, acoustically, compares favorably with conventional prototype devices with silver electrodes. View full abstract»

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  • Electrode position optimization in magnetoelectric sensors based on magnetostrictive-piezoelectric bilayers on cantilever substrates

    Publication Year: 2014 , Page(s): 392 - 398
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    Finite element method (FEM) simulations are performed to investigate the sensitivity to dc magnetic fields of magnetoelectric sensors on cantilever substrates with trenches or weights at different positions. For a simple layered cantilever, a 15% higher signal voltage across the piezoelectric layer is obtained for optimally positioned electrodes and an insulating magnetostrictive material. A further 25% increase in the signal voltage is achieved for a trenched cantilever design with a pick-up region. View full abstract»

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  • Cell membrane deformation induced by a fibronectin-coated polystyrene microbead in a 200-MHz acoustic trap

    Publication Year: 2014 , Page(s): 399 - 406
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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (8328 KB) |  | HTML iconHTML  

    The measurement of cell mechanics is crucial for a better understanding of cellular responses during the progression of certain diseases and for the identification of the cell's nature. Many techniques using optical tweezers, atomic force microscopy, and micro-pipettes have been developed to probe and manipulate cells in the spatial domain. In particular, we recently proposed a two-dimensional acoustic trapping method as an alternative technique for small particle manipulation. Although the proposed method may have advantages over optical tweezers, its applications to cellular mechanics have not yet been vigorously investigated. This study represents an initial attempt to use acoustic tweezers as a tool in the field of cellular mechanics in which cancer cell membrane deformability is studied. A press-focused 193-MHz single-element lithium niobate (LiNbO3) transducer was designed and fabricated to trap a 5-μm polystyrene microbead near the ultrasound beam focus. The microbeads were coated with fibronectin, and trapped before being attached to the surface of a human breast cancer cell (MCF-7). The cell membrane was then stretched by remotely pulling a cell-attached microbead with the acoustic trap. The maximum cell membrane stretched lengths were measured to be 0.15, 0.54, and 1.41 μm at input voltages to the transducer of 6.3, 9.5, and 12.6 Vpp, respectively. The stretched length was found to increase nonlinearly as a function of the voltage input. No significant cytotoxicity was observed to result from the bead or the trapping force on the cell during or after the deformation procedure. Hence, the results convincingly demonstrated the possible application of the acoustic trapping technique as a tool for cell manipulation. View full abstract»

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  • An efficient block matching and spectral shift estimation algorithm with applications to ultrasound elastography

    Publication Year: 2014 , Page(s): 407 - 419
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (13823 KB) |  | HTML iconHTML  

    An efficient block matching and spectral shift estimation algorithm for freehand quasi-static ultrasound elastography is described in this paper. The proposed method provides a balance between computational speed and robustness against displacement estimation error and bias; a fundamental aspect of elastography. The new algorithm was tested on an extensive set of simulated 1-D RF ultrasound signals, replicating various strain profiles. Additionally, real 2-D scans were conducted on an ultrasound phantom with prescribed elastic properties; the algorithm output was further validated with a comparison to a finite element model (FEM) of the phantom. Clinical data from a breast cancer study and histology slides were used to demonstrate the in vivo use of the new elastography technique. The algorithm showed a significant computational savings (at least 60 times faster) over existing spectral shift analysis methods. Accurate strain images were produced in as little as 2 s with the scope for further speed enhancements through parallel processing; making real-time implementation a future possibility. Moreover, it demonstrated a robustness toward displacement estimation error when compared with conventional gradient-based techniques, and was able to perform at high strain values (>5%) while showing relative insensitivity to various parameters settings, such as sample rate and block window size; a desirable performance for a practical clinical tool. View full abstract»

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  • Simulation-based validation for four- dimensional multi-channel ultrasound current source density imaging

    Publication Year: 2014 , Page(s): 420 - 427
    Cited by:  Papers (2)
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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4530 KB) |  | HTML iconHTML  

    Ultrasound current source density imaging (UCSDI), which has application to the heart and brain, exploits the acoustoelectric (AE) effect and Ohm's law to detect and map an electrical current distribution. In this study, we describe 4-D UCSDI simulations of a dipole field for comparison and validation with bench-top experiments. The simulations consider the properties of the ultrasound pulse as it passes through a conductive medium, the electric field of the injected dipole, and the lead field of the detectors. In the simulation, the lead fields of detectors and electric field of the dipole were calculated by the finite element (FE) method, and the convolution and correlation in the computation of the detected AE voltage signal were accelerated using 3-D fast Fourier transforms. In the bench-top experiment, an electric dipole was produced in a bath of 0.9% NaCl solution containing two electrodes, which injected an ac pulse (200 Hz, 3 cycles) ranging from 0 to 140 mA. Stimulating and recording electrodes were placed in a custom electrode chamber made on a rapid prototype printer. Each electrode could be positioned anywhere on an x-y grid (5 mm spacing) and individually adjusted in the depth direction for precise control of the geometry of the current sources and detecting electrodes. A 1-MHz ultrasound beam was pulsed and focused through a plastic film to modulate the current distribution inside the saline-filled tank. AE signals were simultaneously detected at a sampling frequency of 15 MHz on multiple recording electrodes. A single recording electrode is sufficient to form volume images of the current flow and electric potentials. The AE potential is sensitive to the distance from the dipole, but is less sensitive to the angle between the detector and the dipole. Multi-channel UCSDI potentially improves 4-D mapping of bioelectric sources in the body at high spatial resolution, which is especially important for diagnosing and guiding treatment of cardiac and neuro- ogic disorders, including arrhythmia and epilepsy. View full abstract»

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  • Ultrasonic multipath and beamforming clutter reduction: a chirp model approach

    Publication Year: 2014 , Page(s): 428 - 440
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4240 KB) |  | HTML iconHTML  

    In vivo ultrasonic imaging with transducer arrays suffers from image degradation resulting from beamforming limitations, including diffraction-limited beamforming and beamforming degradation caused by tissue inhomogeneity. Additionally, based on recent studies, multipath scattering also causes significant image degradation. To reduce degradation from both sources, we propose a model-based signal decomposition scheme. The proposed algorithm identifies spatial frequency signatures to decompose received wavefronts into their most significant scattering sources. Scattering sources originating from a region of interest are used to reconstruct decluttered wavefronts, which are beamformed into decluttered RF scan lines or A-lines. To test the algorithm, ultrasound system channel data were acquired during liver scans from 8 patients. Multiple data sets were acquired from each patient, with 55 total data sets, 43 of which had identifiable hypoechoic regions on normal B-mode images. The data sets with identifiable hypoechoic regions were analyzed. The results show the decluttered B-mode images have an average improvement in contrast over normal images of 7.3 ± 4.6 dB. The contrast-to-noise ratio (CNR) changed little on average between normal and decluttered Bmode, -0.4 ± 5.9 dB. The in vivo speckle SNR decreased; the change was -0.65 ± 0.28. Phantom speckle SNR also decreased, but only by -0.40 ± 0.03. View full abstract»

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  • An IVUS transducer for microbubble therapies

    Publication Year: 2014 , Page(s): 441 - 449
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1168 KB) |  | HTML iconHTML  

    There is interest in examining the potential of modified intravascular ultrasound (IVUS) catheters to facilitate dual diagnostic and therapeutic roles using ultrasound plus microbubbles for localized drug delivery to the vessel wall. The goal of this study was to design, prototype, and validate an IVUS transducer for microbubble-based drug delivery. A 1-D acoustic radiation force model and finite element analysis guided the design of a 1.5-MHz IVUS transducer. Using the IVUS transducer, biotinylated microbubbles were displaced in water and bovine whole blood to the streptavidin-coated wall of a flow phantom by a 1.5-MHz center frequency, peak negative pressure = 70 kPa pulse with varying pulse repetition frequency (PRF) while monitoring microbubble adhesion with ultrasound. A fit was applied to the RF data to extract a time constant (π). As PRF was increased in water, the time constant decreased (π = 32.6 s, 1 kHz vs. π = 8.2 s, 6 kHz), whereas in bovine whole blood an adhesion-no adhesion transition was found for PRFs ≥ 8 kHz. Finally, a fluorophore was delivered to an ex vivo swine artery using microbubbles and the IVUS transducer, resulting in a 6.6-fold increase in fluorescence. These results indicate the importance of PRF (or duty factor) for IVUS acoustic radiation force microbubble displacement and the potential for IVUS and microbubbles to provide localized drug delivery. View full abstract»

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  • Ultrasound-guided photoacoustic imaging: current state and future development

    Publication Year: 2014 , Page(s): 450 - 466
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (21249 KB) |  | HTML iconHTML  

    Photoacoustic imaging, frequently coregistered with ultrasonic imaging, can provide functional and cellular/ molecular information about tissue within the anatomical landmarks of an imaged region. This review details the fundamentals of photoacoustic imaging and its most promising imaging applications. Particular attention is paid to photoacoustic imaging's relationship with ultrasound, focusing on distinct differences and similarities between the two modalities and highlighting the mutual benefit of using both concurrently in certain preclinical and clinical applications. Much like its origins as an imaging modality were intertwined with ultrasonic imaging (namely, its acoustic transducers and hardware), the future of photoacoustic imaging-particularly in the clinical arena-similarly depends on ultrasound and its time-tested ability to provide real-time visualization of soft tissue. View full abstract»

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  • Self-characterization of commercial ultrasound probes in transmission acoustic inverse scattering: transducer model and volume integral formulation

    Publication Year: 2014 , Page(s): 467 - 480
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5575 KB) |  | HTML iconHTML  

    A self-contained source characterization method for commercial ultrasound probes in transmission acoustic inverse scattering is derived and experimentally tested. The method is based on modified scattered field volume integral equations that are linked to the source-scattering transducer model. The source-scattering parameters are estimated via pair-wise transducer measurements and the nonlinear inversion of an acoustic propagation model that is derived. This combination creates a formal link between the transducer characterization and the inverse scattering algorithm. The method is tested with two commercial ultrasound probes in a transmission geometry including provisions for estimating the probe locations and aligning a robotic rotator. The transducer characterization results show that the nonlinear inversion fit the measured data well. The transducer calibration and inverse scattering algorithm are tested on simple targets. Initial images show that the recovered contrasts are physically consistent with expected values. View full abstract»

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  • Review of high-power ultrasound-industrial applications and measurement methods

    Publication Year: 2014 , Page(s): 481 - 495
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2314 KB) |  | HTML iconHTML  

    Applications involving high-power ultrasound are expanding rapidly as ultrasonic intensification opportunities are identified in new fields. This is facilitated through new technological developments and an evolution of current systems to tackle challenging problems. It is therefore important to continually update both the scientific and commercial communities on current system performance and limitations. To achieve this objective, this paper addresses two key aspects of high-power ultrasonic systems. In the first part, the review of high-power applications focuses on industrial applications and documents the developing technology from its early cleaning applications through to the advanced sonochemistry, cutting, and water treatment applications used today. The second part provides a comprehensive overview of measurement techniques used in conjunction with high-power ultrasonic systems. This is an important and evolving field which enables design and process engineers to optimize the behavior and/or operation of key metrics of system performance, such as field distribution or cavitation intensity. View full abstract»

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  • Application of conformal map theory for design of 2-D ultrasonic array structure for ndt imaging application: a feasibility study

    Publication Year: 2014 , Page(s): 496 - 504
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    Two-dimensional ultrasonic phased arrays are becoming increasingly popular in nondestructive evaluation (NDE). Sparse array element configurations are required to fully exploit the potential benefits of 2-D phased arrays. This paper applies the conformal mapping technique as a means of designing sparse 2-D array layouts for NDE applications. Modeling using both Huygens' field prediction theory and 2-D fast Fourier transformation is employed to study the resulting new structure. A conformal power map was used that, for fixed beam width, was shown in simulations to have a greater contrast than rectangular or random arrays. A prototype aperiodic 2-D array configuration for direct contact operation in steel, with operational frequency ~3 MHz, was designed using the array design principle described in this paper. Experimental results demonstrate a working sparse-array transducer capable of performing volumetric imaging. View full abstract»

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  • Acoustic precursor wave propagation in viscoelastic media

    Publication Year: 2014 , Page(s): 505 - 514
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1703 KB) |  | HTML iconHTML  

    Precursor field theory has been developed to describe the dynamics of electromagnetic field evolution in causally attenuative and dispersive media. In Debye dielectrics, the so-called Brillouin precursor exhibits an algebraic attenuation rate that makes it an ideal pulse waveform for communication, sensing, and imaging applications. Inspired by these studies in the electromagnetic domain, the present paper explores the propagation of acoustic precursors in dispersive media, with emphasis on biological media. To this end, a recently proposed causal dispersive model is employed, based on its interpretation as the acoustic counterpart of the Cole-Cole model for dielectrics. The model stems from the fractional stress-strain relation, which is consistent with the empirically known frequency power-law attenuation in viscoelastic media. It is shown that viscoelastic media described by this model, including human blood, support the formation and propagation of Brillouin precursors. The amplitude of these precursors exhibits a sub-exponential attenuation rate as a function of distance, actually being proportional to z-p, where z is the distance traveled within the medium and 0.5 <; p <; 1. The precursors identified in this work facilitate the design of optimal waveforms for propagation in complex media, creating new possibilities for acoustic-pulse-based communication and imaging systems. View full abstract»

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  • An improved wave-vector frequency-domain method for nonlinear wave modeling

    Publication Year: 2014 , Page(s): 515 - 524
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1246 KB) |  | HTML iconHTML  

    In this paper, a recently developed wave-vector frequency-domain method for nonlinear wave modeling is improved and verified by numerical simulations and underwater experiments. Higher order numeric schemes are proposed that significantly increase the modeling accuracy, thereby allowing for a larger step size and shorter computation time. The improved algorithms replace the left-point Riemann sum in the original algorithm by the trapezoidal or Simpson's integration. Plane waves and a phased array were first studied to numerically validate the model. It is shown that the left-point Riemann sum, trapezoidal, and Simpson's integration have first-, second-, and third-order global accuracy, respectively. A highly focused therapeutic transducer was then used for experimental verifications. Short high-intensity pulses were generated. 2-D scans were conducted at a prefocal plane, which were later used as the input to the numerical model to predict the acoustic field at other planes. Good agreement is observed between simulations and experiments. View full abstract»

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  • Sensitivity analysis of multi-layered C-axis inclined zigzag zinc oxide thin-film resonators as viscosity sensors

    Publication Year: 2014 , Page(s): 525 - 534
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1306 KB) |  | HTML iconHTML  

    This paper presents a theoretical analysis of a new zigzag C-axis inclined multi-layer ZnO thin-film bulk acoustic wave resonator (FBAR) as a viscosity sensor to monitor the lubrication performance of engine oil and other liquids. Free vibration and forced vibration for the FBAR loaded with liquids are analyzed. Equations necessary to calculate the sensitivity are derived. The numerical analysis shows that as the number of layers increases, the absolute sensitivity increases as well. The influences on the sensitivity of C-axis inclined angle, Q-factor, and thickness are also investigated. The results provide a foundation for further design of multi-layer FBAR viscosity sensors. View full abstract»

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  • Design and optimization of a modal- independent linear ultrasonic motor

    Publication Year: 2014 , Page(s): 535 - 546
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6882 KB) |  | HTML iconHTML  

    To simplify the design of the linear ultrasonic motor (LUSM) and improve its output performance, a method of modal decoupling for LUSMs is proposed in this paper. The specific embodiment of this method is decoupling of the traditional LUSM stator's complex vibration into two simple vibrations, with each vibration implemented by one vibrator. Because the two vibrators are designed independently, their frequencies can be tuned independently and frequency consistency is easy to achieve. Thus, the method can simplify the design of the LUSM. Based on this method, a prototype modal-independent LUSM is designed and fabricated. The motor reaches its maximum thrust force of 47 N, maximum unloaded speed of 0.43 m/s, and maximum power of 7.85 W at applied voltage of 200 Vpp. The motor's structure is then optimized by controlling the difference between the two vibrators' resonance frequencies to reach larger output speed, thrust, and power. The optimized results show that when the frequency difference is 73 Hz, the output force, speed, and power reach their maximum values. At the input voltage of 200 Vpp, the motor reaches its maximum thrust force of 64.2 N, maximum unloaded speed of 0.76 m/s, maximum power of 17.4 W, maximum thrust-weight ratio of 23.7, and maximum efficiency of 39.6%. View full abstract»

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  • Lead zirconate titanate-based thick films for high-frequency focused ultrasound transducers prepared by electrophoretic deposition

    Publication Year: 2014 , Page(s): 547 - 556
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6453 KB) |  | HTML iconHTML  

    An electrophoretic deposition (EPD) process with high deposition rate was used to fabricate a curved piezoelectric thick film devoted to high-frequency transducers for medical imaging. Niobium-doped lead zirconate titanate (PZTNb) powder was stabilized in ethanol to prepare a suspension with high zeta potential and low conductivity. A gold layer, pad-printed and fired on a curved porous PZT substrate, was used as the working electrode for the deposition of the PZTNb thick film. This substrate was chosen because it has the required properties (acoustic impedance and attenuation) to be used directly as a backing for the high-frequency transducer, leading to a simplified process for transducer assembly with this integrated structure. PZT-Nb thick films were also deposited by EPD on flat gold-coated alumina substrates as a reference. The thickness of the films was between 20 and 35 μm, and their electromechanical performance was comparable to standard PZT bulk ceramics with a thickness coupling factor of 48%. For the curved thick film, the thickness coupling factor was slightly lower. The corresponding integrated structure was used to fabricate a transducer with a center frequency of 40 MHz and an f-number of 2.8. It was integrated into a realtime ultrasound scanner and used to image human forearm skin; the resulting images showed, for the first time, the efficacy of the EPD process for these imaging applications. View full abstract»

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Aims & Scope

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control focuses on the theory, design, and application on generation, transmission, and detection of bulk and surface mechanical waves.

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Editor-in-Chief
Steven Freear
s.freear@leeds.ac.uk