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IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Issue 2 • March 1989

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Displaying Results 1 - 20 of 20
  • High-rangeability ultrasonic gas flowmeter for monitoring flare gas

    Publication Year: 1989, Page(s):144 - 149
    Cited by:  Papers (25)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (495 KB)

    A transit-time ultrasonic gas flowmeter for high-rangeability requirements, such as those encountered in flare-gas flow-metering, is presented. The concept of ray rescue angle for the orientation of the ultrasonic transducers in single-beam transit-time ultrasonic flowmeters is introduced to overcome the problem of ultrasonic beam drift in high-velocity flows. To overcome problems associated with ... View full abstract»

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  • ZnO-on-Si mode conversion resonator

    Publication Year: 1989, Page(s):150 - 158
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (784 KB)

    A two-port admittance matrix model is presented to describe the operation of the surface-acoustic-wave (SAW) mode conversion resonator. A unique treatment of the transducer coupling is applied to the specific case of the mode conversion device. The model takes into account the simultaneous presence of propagating Rayleigh and Sezawa waves and allows an equivalent circuit to be constructed to descr... View full abstract»

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  • Optimized Stoneley wave device by proper choice of glass overcoat

    Publication Year: 1989, Page(s):159 - 167
    Cited by:  Papers (5)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (857 KB)

    The characteristics of a Stoneley wave propagated along an interface between a piezoelectric material and an isotropic material were investigated both theoretically and experimentally. First, the condition for the existence of Stoneley waves was shown for various piezoelectric materials. A rule of thumb for selecting the combination of the two materials was obtained. Then, LiTaO/sub 3/ was selecte... View full abstract»

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  • Phase correction of SAW ILRACs and RACs using Langmuir-Blodgett films

    Publication Year: 1989, Page(s):168 - 177
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (942 KB)

    A novel method of adjusting surface-acoustic-wave (SAW) velocity in reflective array pulse compressors (RACs), including in-line devices (ILRACs) and hence correcting fabrication errors, is described. The velocity change is effected by depositing Langmuir-Blodgett films (LBFs) on the surface of the device. An accurate, stepped thickness profile can be created, enabling position-dependent velocity ... View full abstract»

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  • SAW focusing by circular-arc interdigital transducers on YZ-LiNbO/sub 3/

    Publication Year: 1989, Page(s):178 - 184
    Cited by:  Papers (17)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (588 KB)

    Using the angular spectrum theory and experimental velocity data of surface acoustic waves (SAW) on YZ-LiNbO/sub 3/, the focusing characteristics of a circular-arc interdigital transducer have been demonstrated. The calculated results show that the depth of focus is long and the compressed acoustic beam width is very narrow. The concept of a caustic is shown to be an excellent way of characterizin... View full abstract»

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  • A three-dimensional model of the gas cell atomic frequency standard

    Publication Year: 1989, Page(s):185 - 190
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (597 KB)

    Initial calculations from a three-dimensional (3-D) model of the gas cell atomic frequency standard are discussed. In particular, a recent suggestion that the short-term stability of a gas cell standard might be improved by varying the microwave power is considered. Though the authors' results generally support the previous conclusion, they show that the degree of sensitivity is less than that pre... View full abstract»

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  • Thermal modeling in cylindrical coordinates using effective conductivity

    Publication Year: 1989, Page(s):191 - 196
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (466 KB)

    Predictive thermometry, utilizing minimally invasive sampling techniques, is an essential ingredient in the development of hyperthermia treatment planning capabilities. The authors demonstrate a powerful, but simple approach toward predicting temperature distributions in tissues, based on analytic solution, using in cylindrical symmetry, of the heat diffusion equation. Conduction and localized per... View full abstract»

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  • Acoustic attenuation estimation for soft tissue from ultrasound echo envelope peaks

    Publication Year: 1989, Page(s):197 - 203
    Cited by:  Papers (14)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (633 KB)

    A theoretical framework of a modified EP (envelope peak) method is developed. In this method, a wideband echo signal from each A line (one echo sequence) is first filtered in parallel by a bank of narrow-bandpass filters using a split-spectrum processing. The attenuation is then estimated from the EPs of each filtered signal using a narrowband technique. The combination of the split-spectrum proce... View full abstract»

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  • An improved theory for the prediction of microcavitation thresholds

    Publication Year: 1989, Page(s):204 - 208
    Cited by:  Papers (95)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (474 KB)

    An approximate analytical formulation is presented that allows for the calculation of acoustic pressure thresholds for transient cavitation over a variety of frequencies and host fluid parameters. Specifically, R.E. Apfel's (1986) theory is extended to include an estimate of the time delay associated with the Laplace pressure, 2 sigma /R/sub 0/, where sigma is the surface tension and R/sub 0/ is t... View full abstract»

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  • Focusing ultrasound in biological media

    Publication Year: 1989, Page(s):209 - 215
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (707 KB)

    The authors present a formulation for calculating the field distributions for an ultrasonic imaging system when focusing in biological media. A biological medium is characterized in terms of its complex and frequency-dependent compressibility that, in turn, depends on the medium relaxation time and specific heat ratio. The analysis is based on a spatial/temporal transfer function formalism and can... View full abstract»

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  • Power spectrum equalization for ultrasonic image restoration

    Publication Year: 1989, Page(s):216 - 222
    Cited by:  Papers (28)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (799 KB)

    A method of image restoration for ultrasonic B-scan images has been proposed that need no a priori knowledge on the PSF (point spread function) of the imaging system and is feasible for in vivo applications. The entire system's response, including the interposed medium and possible transducer defects, is estimated from the degraded image itself with a few simple operations. The ultrasonic image is... View full abstract»

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  • Electromechanical coupling to Lamb and shear-horizontal modes in piezoelectric plates

    Publication Year: 1989, Page(s):223 - 230
    Cited by:  Papers (26)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (555 KB)

    Recent theoretical studies and experiments have been shown that interdigital transducers can couple strongly to plate modes in piezoelectric materials and in piezoelectric-on-nonpiezoelectric composite membranes. The calculated velocity dispersion and electromechanical coupling factors for plate modes in representative piezoelectric materials are described. The frequency dependence of velocity and... View full abstract»

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  • Thin-film induced effects on the stability of SAW devices

    Publication Year: 1989, Page(s):231 - 241
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1023 KB)

    Measurements show an upward shift on the order of 50 ppm in the resonant frequency of a surface acoustic wave (SAW) resonator, as taken before and after the device is hermetically sealed in vacuum following a certain glass-frit sealing process. The authors analyze some of the thin-film phenomena that are potential sources of the observed frequency shift and that may affect the long-term stability ... View full abstract»

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  • Sound field calculation for rectangular sources

    Publication Year: 1989, Page(s):242 - 248
    Cited by:  Papers (111)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB)

    A method is presented for calculation of the sound field from a rectangular continuous-wave source surrounded by a plane grid baffle. The approach is illustrated for square sources of 0.5, 1, 2, 5, 10, 20, and 100 lambda on a side. These results are compared to the sound fields produced by similarly sized circular sources. The beam widths and locations of on-axis minima are similar for the two sou... View full abstract»

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  • The sector-vortex phased array: acoustic field synthesis for hyperthermia

    Publication Year: 1989, Page(s):249 - 257
    Cited by:  Papers (54)  |  Patents (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (990 KB)

    A sector-vortex phased array capable of generating directly annular-shape foci is analyzed. By driving the sectors of the array with signals whose phase rotates M times around the circular track, annular foci with the same acoustic-signal-phase rotation are produced in the geometrical focal plane of the array. Because of this phase modulation around the focal annuli and the resulting high-spatial-... View full abstract»

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  • Wideband acoustic microscopy of tissue

    Publication Year: 1989, Page(s):258 - 263
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (803 KB)

    A scanning acoustic microscope (SAM) has been used to measure the elastic properties of tissue with a resolution of around 8 mu m. This is achieved by broadband excitation of the acoustic lens, and the recording of an undemodulated returning signal. A method of analyzing this information to yield sound velocity, acoustic impedance, section thickness, and acoustic attenuation is described. Results ... View full abstract»

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  • Improvement of anisotropy sensitivity in the scanning acoustic microscope

    Publication Year: 1989, Page(s):264 - 273
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (871 KB)

    The response of the conventional scanning acoustic microscope (SAM) to anisotropic materials is theoretically investigated. For this purpose, the reflection coefficient of plane acoustic waves incident on a liquid-solid interface is numerically calculated for a general anisotropic solid oriented in any arbitrary direction. In general, the reflection coefficient depends on polar and azimuthal angle... View full abstract»

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  • Experimental observation of plastic deformation areas, using an acoustic microscope

    Publication Year: 1989, Page(s):274 - 279
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (743 KB)

    Novel techniques are described for the observation of plastic deformation areas by using an acoustic microscope. On a test piece subjected to plastic deformation, an area was found that had an abnormal contrast in the crystal grain and a pointed end at the V notch. Calculation of the propagation velocity of the surface acoustic wave (SAW) showed a difference of several percent between this area an... View full abstract»

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  • Reciprocal relations for transmission coefficients: theory and application

    Publication Year: 1989, Page(s):280 - 286
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (551 KB)

    The authors present a rigorous proof of certain intuitively plausible reciprocal relations for time harmonic plane-wave transmission and reflection at the interface between a fluid and an anisotropic elastic solid. Precise forms of the reciprocity relations for the transmission coefficients and for the transmitted energy fluxes are derived, based on the reciprocity theorem of elastodynamics. It is... View full abstract»

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  • Shear-horizontal surface waves on piezoelectric ceramics with depolarized surface layer

    Publication Year: 1989, Page(s):287 - 293
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (581 KB)

    Theoretical analysis and numerical results describing the propagation of SH (shear-horizontal) surface waves on piezoelectric ceramics with a depolarized surface layer are described. SH surface waves propagating in piezoelectric ceramics with a depolarized surface layer are shown to be a mixture of the Bleustein-Gulyaev surface wave, electrical potential, and the Love surface-wave mechanical displ... 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