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IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Issue 2 • Date March 1995

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Displaying Results 1 - 25 of 27
  • Sweeping investigations on as grown Al-Li/sup +/ and Al-OH/sup -/ centers in natural crystalline quartz

    Publication Year: 1995, Page(s):153 - 158
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (361 KB)

    In the present work, we have used near infrared absorption in the region 3100-3700 cm/sup -1/ to study a variety of optically clear samples of natural quartz crystals of Brazilian and Arkansas origins. The crystals used were hydrogen-rich and hydrogen-lean with approximately equal and also of varying aluminum concentrations. The alkali-H concentration in hydrogen-rich samples was much higher than ... View full abstract»

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  • SAW filters with high stopband rejection based on a cascade connection of selective elements

    Publication Year: 1995, Page(s):159 - 163
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (259 KB)

    To achieve a high stopband rejection in surface acoustic wave (SAW) filters a construction that includes a cascade of some elements (interdigital transducers (IDT) and multistrip couplers (MSC)) is used. In this case each element has to maintain a comparatively low frequency selectivity, and this permits a simple model and a high-speed calculation process to be employed for its design. The propose... View full abstract»

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  • Withdrawal weighted fan-shaped SAW transducers

    Publication Year: 1995, Page(s):164 - 167
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (218 KB)

    Withdrawal weighted (WW) fan-shaped interdigital transducers (FIDT) are used to design surface acoustic wave (SAW) filters with a good shape factor, a flat passband, and an out-of-band rejection of 50 dB and more. Utilization of "stepped" actions as a weighting action for FIDT's ensures a simple filter structure synthesis procedure that does not take a long time on a personal computer. Three modif... View full abstract»

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  • Scattering of SAW at discontinuities: some numerical experiments

    Publication Year: 1995, Page(s):168 - 173
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (277 KB)

    In developing models to characterize the metallic-finger step discontinuity in SAW devices on piezoelectric substrates it is important to estimate the SAW reflection coefficients and the effect of other modes at step discontinuities. In the literature perturbation approximations, finite element methods and various phenomenological parameter-fitting using experimental data are among the techniques ... View full abstract»

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  • Acoustic wave propagation along cladded fibers of trigonal crystal symmetry

    Publication Year: 1995, Page(s):174 - 181
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (282 KB)

    An approximate method is proposed to analyze the acoustic wave propagation characteristics in nonpiezoelectric cladded LiNbO/sub 3/ fibers of trigonal crystal symmetry. The fiber axis coincides with the crystalline Z axis and the cladding thickness is infinite. This method utilizes coupled mode equations and exact solutions for corresponding cladded fibers of hexagonal crystal symmetry are used as... View full abstract»

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  • Evaluation of accuracy of a theoretical model for predicting the necrosed tissue volume during focused ultrasound surgery

    Publication Year: 1995, Page(s):182 - 187
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (307 KB)

    The concept of thermal dose as a predictor for the size of the necrosed tissue volume during high-intensity focussed ultrasound surgery was tested. The sensitivity of the predicted lesion size to the uncertainties in the iso-dose constant, attenuation coefficient, and thermal dose threshold of necrosis was studied. The predicted lesion size appears to be independent of attenuation at some high att... View full abstract»

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  • Optoelectronic transmitters for medical ultrasound transducers

    Publication Year: 1995, Page(s):188 - 199
    Cited by:  Papers (5)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2229 KB)

    Optoelectronics and fiber optics can be used to miniaturize and improve the flexibility of the transducer cable and transducer handle of medical diagnostic ultrasound scanners. The reduction in size has gained importance as 2-D array transducers with up to 1000 independent channels become accepted to improve diagnostic ultrasound images. The authors describe the analysis, design, fabrication and t... View full abstract»

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  • Blood noise reduction in intravascular ultrasound imaging

    Publication Year: 1995, Page(s):200 - 209
    Cited by:  Papers (5)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1941 KB)

    Scattering from red blood cells (blood noise) increases significantly as the ultrasound frequency is increased above 10 MHz. This reduces the contrast between the vessel wall and the lumen in intravascular ultrasound imaging which makes it difficult to localize the vessel wall and plaque. A blood noise filter based on beam tilting and digital lateral low pass filtering is described. Beam tilting i... View full abstract»

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  • Modeling of a piezoelectric rotary ultrasonic motor

    Publication Year: 1995, Page(s):210 - 224
    Cited by:  Papers (88)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (682 KB)

    A piezoelectric rotary ultrasonic motor is modeled for the purpose of predicting, a priori, motor performance as a function of design parameters. The Rayleigh-Ritz assumed mode energy method is used to model the distributed piezoceramics and the traveling wave dynamics of the stator. Natural frequencies and modeshapes are obtained for a generally configured motor. Nonlinear normal and tangential i... View full abstract»

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  • Design of a traveling wave type ultrasonic motor

    Publication Year: 1995, Page(s):225 - 231
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (322 KB)

    The purpose of the present paper is to establish a method of design for a traveling wave type ultrasonic motor. This method is based on two models for the ultrasonic motor. A two-dimensional elastic contact model is used for estimating the friction drive between the rotor and vibrator of the motor. Moreover, an electrical equivalent circuit is used to estimate the interaction between the electrica... View full abstract»

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  • Diffraction effects in insertion mode estimation of ultrasonic group velocity

    Publication Year: 1995, Page(s):232 - 242
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (552 KB)

    We describe diffraction effects in ultrasonic group velocity estimation using an insertion technique. We characterize the estimation error produced by diffraction as a function of distance and nominal velocity values. A new method termed Group Velocity Diffraction Correction (GVDC) which corrects for the diffraction effect is presented. Experimental validation of the technique is also presented us... View full abstract»

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  • A general approximated two-dimensional model for piezoelectric array elements

    Publication Year: 1995, Page(s):243 - 252
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 KB)

    In this paper we describe an approximate two-dimensional model of a single piezoelectric array element. Substantially, the element is a two-dimensional structure whose vibrations can be described by two coupled differential wave equations with coupled boundary conditions. We take as a solution of this system two orthogonal wave functions which depend only on one axis, corresponding to the propagat... View full abstract»

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  • Acoustic microscopy measurement of elastic constants and mass density

    Publication Year: 1995, Page(s):253 - 264
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (532 KB)

    A method is presented to determine the elastic constants and the mass density of isotropic and anisotropic solids and anisotropic thin films. The velocity and attenuation of leaky surface acoustic waves (SAWs) have been obtained for specified propagation directions from V(z) curves measured by line-focus acoustic microscopy (LFAM). The experimentally obtained velocities have been compared to veloc... View full abstract»

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  • A new pulsed wave Doppler ultrasound system to measure blood velocities beyond the Nyquist limit

    Publication Year: 1995, Page(s):265 - 279
    Cited by:  Papers (10)  |  Patents (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2264 KB)

    Conventional pulsed wave (PW) Doppler ultrasound systems measure blood velocities unambiguously as long as the velocities are less than the Nyquist velocity. Here, a new PW Doppler ultrasound system is described, which can measure velocities up to 4.5 times higher than the Nyquist velocity. The new PW system presented here utilizes two ultrasound carrier frequencies, such that an appropriate proce... View full abstract»

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  • Periodic Green's functions analysis of SAW and leaky SAW propagation in a periodic system of electrodes on a piezoelectric crystal

    Publication Year: 1995, Page(s):280 - 293
    Cited by:  Papers (42)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (662 KB)

    A method of periodic Green's functions with a propagation factor exp(i/spl beta/x), unknown in advance, is used to calculate dispersion curves and attenuation coefficients for Rayleigh- and leaky- waves propagating in a periodic system of thin electrodes on a piezoelectric surface. To describe the charge distribution on the electrodes both a step approximation and Chebyshev polynomials are used, t... View full abstract»

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  • A dual frequency ultrasonic probe for medical applications

    Publication Year: 1995, Page(s):294 - 300
    Cited by:  Papers (24)  |  Patents (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (995 KB)

    A dual frequency probe using a multilayer ceramic is proposed for simultaneously obtaining a high resolution B mode and a high sensitivity Doppler mode image. This ceramic consists of two layers in which the poling directions are opposite and the individual thicknesses are different. It is possible to control the values of relative electromechanical coupling factors in the fundamental and the seco... View full abstract»

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  • A fundamental limit on delay estimation using partially correlated speckle signals

    Publication Year: 1995, Page(s):301 - 308
    Cited by:  Papers (141)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (318 KB)

    Delay estimation is used in ultrasonic imaging to estimate blood or soft tissue motion, to measure echo arrival time differences for phase aberration correction, and to estimate displacement for tissue elasticity measurements. In each of these applications delay estimation is performed using speckle signals which are at least partially decorrelated relative to one another. Delay estimates which ut... View full abstract»

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  • Contrast medium assisted fluid flow measurements

    Publication Year: 1995, Page(s):309 - 315
    Cited by:  Papers (4)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    In this paper the development and evaluation of two new approaches for ultrasound time-domain fluid flow measurements by tracking echoes scattered by a contrast agent following injection of a bolus of the contrast agent are described. Their feasibility was investigated by measuring velocity or velocity profile of blood flowing in a mock circulatory loop in vitro. Measurements were made with a one ... View full abstract»

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  • A 100-MHz ultrasonic transducer array using ZnO thin films

    Publication Year: 1995, Page(s):316 - 324
    Cited by:  Papers (27)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1930 KB)

    A 100-MHz ultrasonic linear transducer array made from a piezoelectric zinc oxide thin film on a sapphire substrate was developed and evaluated. Epitaxial, high-acoustic quality 10-/spl mu/m-thick ZnO film layers were produced by rf-magnetron sputter deposition onto a (111)-oriented gold film (with a chromium adhesion layer) that was vacuum-evaporated onto a (0001) sapphire surface. We found that,... View full abstract»

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  • Table of contents - Front cover

    Publication Year: 1995, Page(s): i
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    Freely Available from IEEE
  • [Inside front cover]

    Publication Year: 1995, Page(s): ii
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    Freely Available from IEEE
  • [Back inside cover]

    Publication Year: 1995, Page(s): iii
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    Freely Available from IEEE
  • Information for Contributors - Back Cover

    Publication Year: 1995, Page(s): iv
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    Freely Available from IEEE
  • Final Announcement and Call for Papers - The 22nd International Symposium on Acoustical Imaging

    Publication Year: 1995, Page(s): 325
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    Freely Available from IEEE
  • Call for Papers - Special Issue on Applications

    Publication Year: 1995, Page(s): 326
    Request permission for commercial reuse | PDF file iconPDF (38 KB)
    Freely Available from IEEE

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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Meet Our Editors

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