1993 Proceedings IEEE Ultrasonics Symposium

31 Oct-3 Nov 1993

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Displaying Results 1 - 25 of 260
  • Temperature dependence of ultrasonic attenuation in the superconducting state of the heavy fermion compound UPt3

    Publication Year: 1993, Page(s):799 - 802 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Longitudinal ultrasonic attenuation at frequencies up to 450 MHz on a single crystal UPt3 sample was measured in the superconducting state down to about 50 mK. A new technique was used, in which the resolution of both attenuation and velocity was significantly improved. After being normalized by the normal state attenuation, the superconducting attenuation at different frequencies exhib... View full abstract»

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  • Ultrasonic velocity measurements of isotopically enriched diamonds

    Publication Year: 1993, Page(s):803 - 806 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    We have performed ultrasonic pulse-echo experiments to measure the longitudinal and transverse acoustic velocities in nine single-crystal manufactured diamonds. Small (4-5%) but distinct decreases in both the longitudinal and transverse [100] velocities were observed as the 13C content varied from 0% to 99%. The measurements indicated that within our uncertainty (typically <0.5%), c<... View full abstract»

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  • Ultrasonic study of mixed ferroelectrics in a DC bias field

    Publication Year: 1993, Page(s):807 - 810 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    Polarization and Raman measurements, in KTa1-XNbX O3 (KTN), have shown the existence of precursor effects many degrees above the transition. These effects are due to the formation of polar nanoregions, or clusters, which also explain the departure of the susceptibility from its Curie-Weiss dependence at high temperature. It was also shown through ultrasonic measure... View full abstract»

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  • Elastic properties of SnO2 films

    Publication Year: 1993, Page(s):811 - 814 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB)

    SnO2 films have been recently used as reactive materials in gas sensors based on change of the electrical resistivity under gas exposure. In view of potential application of these films to surface acoustic waves (SAW) sensors, knowledge of their elastic properties is of current interest. We report here on results of the elastic characterization of SnO2 films, with thicknesses... View full abstract»

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  • Target structure dependence of the linearity principle in the estimation of underwater target abundance by the echo integration method

    Publication Year: 1993, Page(s):719 - 722 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    The estimation of fish abundance by the echo integration method is based on the assumption that the total integrated echo intensity returned from randomly distributed targets is proportional to the quantity of those targets. The validity of this assumption depends not only on the number density of targets under investigation, but also on their physical structure. This is evidenced by a study of th... View full abstract»

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  • Photoacoustic signals from the ion-implanted layer of silicon substrate

    Publication Year: 1993, Page(s):815 - 818 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    A nonradiative transition in ion-implanted and epitaxially grown layers on Si substrate were measured by a piezoelectric photoacoustic (PA) spectroscopy. It is considered that the observed peak at 1.07 eV is caused by a nonradiative recombination of optically excited electrons from boron acceptor levels. The decrease of the 1.07 eV peak intensity by ion implantation is considered to be due to a fo... View full abstract»

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  • MIMO identification of parametric models for ultrasonic reflection and transmission experiments

    Publication Year: 1993, Page(s):723 - 728 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    This paper presents a multiple input multiple output (MIMO) identification approach, combining both reflection and transmission data from experiments performed on a linear viscoelastic material at normal incidence. The parametric modeling of the wave propagation, the calibration of the measurement setup and the estimation of the model parameters are elaborated. The broadband absorption-dispersion ... View full abstract»

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  • Elastic surface wave devices based on piezoelectric thick films

    Publication Year: 1993, Page(s):281 - 285 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    A study has been performed for the development of elastic-wave structures, involving screen printed and fired piezoelectric layers on non-piezoelectric substrates, intended for new families of thick film sensors. This study considers electroacoustic effects, i.e. the coupling between the electromechanical parameters of the layers and the elastic properties of the substrate, related to wave propaga... View full abstract»

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  • Analysis of excitation and propagation of acoustic waves under periodic metallic-grating structure for SAW device modeling

    Publication Year: 1993, Page(s):143 - 148 vol.1
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    Aiming at developing a sophisticated simulation tool for SAW devices, this paper proposes a method of analysing the excitation and propagation of acoustic waves under a periodic metallic-grating structure. It is shown that on periodic metallic-grating electrodes, electric charges and potential are related by the newly defined discrete Green function, which can be evaluated by applying the complex ... View full abstract»

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  • Determination of thermal parameters of semiconductors by photoacoustic phase angle technique

    Publication Year: 1993, Page(s):819 - 822 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    Photoacoustic (PA) technique in the gas microphone configuration has been employed to determine the thermal properties of GaAs samples using the phase angle measurements in the saturation region. The doped samples are either n-type (6.9×1017-5.6×1018 ) or p-type (2.08×1017-2.1×1020). The values of the thermal diffusivity (α)... View full abstract»

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  • The quasistatic process in pulsed photothermal detection

    Publication Year: 1993, Page(s):823 - 826 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    In the pulsed photothermal (PT) displacement detection, the signal displays an apparent quasistatic characteristic, i.e., the signal reaches its maximum point rapidly, and then decreases exponentially. For a quantitative numerical simulation, the quasistatic approximation, i.e., neglecting the inertia term in the thermoelastic displacement equation, is usually considered, which is different from t... View full abstract»

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  • Microstructuring technology

    Publication Year: 1993, Page(s):515 - 524 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (632 KB)

    Piezoelectric transducers for medical imaging and non-destructive evaluation are increasingly based on composite materials, especially 1-3 composites. The known methods to prepare such transducers and in particular the widely used dice-and-fill technique are reviewed and discussed with respect to the specific advantages and limitations. Technologies using the micro-structuring of green ceramic bod... View full abstract»

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  • 2.5 GHz-range SAW propagation and reflection characteristics and application to passive electronic tag and matched filter

    Publication Year: 1993, Page(s):1267 - 1270 vol.2
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    Surface acoustic waves have been applied in various electronic devices. A signal processing device using SAW is one of the important applications. The devices operating at higher frequencies should be developed. In this paper, 2.5 GHz-range SAW excitation, propagation and reflection characteristics are experimentally investigated. The attenuation of SAW on 128° Y-X LiNbO3 is 0.0035 ... View full abstract»

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  • Control of second order temperature coefficient of SAW propagating in two thin film layers

    Publication Year: 1993, Page(s):287 - 290 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    This study proposes a new control method of the 1st- and 2nd-order temperature coefficients of two-layer substrate composed of ZnO and Ta 2O5 thin films which have the 2nd-order temperature coefficients of delay time with the signs opposite to each other. As a result, a stable SAW substrate of ZnO/Ta2O5 /fused quartz showing the 3rd-order characteristics... View full abstract»

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  • Evaluation of the performance of strategies for the estimation of low velocity blood flow

    Publication Year: 1993, Page(s):1049 - 1053 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    Current color flow mapping systems are limited in their ability to detect slow blood flow, and to accurately estimate flow velocities in a region that contains vessels with rapid flow as well as slow blood flow. We present results of simulation and in vitro experiments which compare the performance of the following estimation strategies: the autocorrelator, a second order Burg autoregressive estim... View full abstract»

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  • Nonlinear acoustic wave propagation in tissue medium

    Publication Year: 1993, Page(s):939 - 942 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    Measurements to comply with labeling standards and FDA requirements for diagnostic equipment are performed in water, a medium readily available and easy to use. To predict the fields in tissue, an attenuating and absorbing medium, the FDA has established a derating factor of 0.3 dB/cm-MHz. This model, however, is based on a simple linear model which does not take into account the nonlinearity of t... View full abstract»

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  • Full-wave 3D analysis of wave scattering on SAW-structures with finite aperture

    Publication Year: 1993, Page(s):149 - 152 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The interaction of surface and bulk acoustic waves with arbitrarily shaped electrodes of finite aperture and negligible thickness, located on the surface of a piezoelectric substrate is analyzed. The reflectivity of a finite number of coupled electrodes is calculated. The reflectivity calculations take into account the following: (i) the 2D geometry of the electrodes involved, (ii) the frequency, ... View full abstract»

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  • SAW devices in wireless communication systems

    Publication Year: 1993, Page(s):115 - 124 vol.1
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    This paper discusses SAW applications in wireless communication systems. Recent developments in SAW resonator technology have made it possible to design and economically manufacture devices with very low insertion losses. One-port resonators with insertion losses of 1 to 2 dB and chip sizes similar to the former higher loss units are receiving widespread acceptance in the wireless marketplace. Clo... View full abstract»

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  • Air coupled piezoelectric detection of laser generated ultrasound

    Publication Year: 1993, Page(s):651 - 654 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    This paper presents the deployment of a pulsed laser to generate ultrasonic transients in samples of metal and their subsequent through air detection by a 1-3 connectivity composite transducer. Of particular interest is a class of reception devices that utilises the coupling of lateral vibrational modes to extend effectively the thickness-mode bandwidth. The characteristics of the laser generation... View full abstract»

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  • The status of ultrasonic flowmeters in Russia

    Publication Year: 1993, Page(s):395 - 399 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    From the West's latest scientific publications, it is clear that many interesting results of Russian researchers are not known to Western researchers because of the language barrier. The first experimental models of ultrasonic flowmeters in the USSR were designed in 1956 by Z.M. Shafranovskaia and colleagues in the Research Institute of Heat and Power Instrumentation and then in 1957-1959 by N.I. ... View full abstract»

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  • Field of circumferential acoustical logging devices

    Publication Year: 1993, Page(s):827 - 830 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    The circumferential acoustical device (CAD) is an acoustic logging tool for use in oil wells as a detector of vertical or near vertical fractures of the formation. Opposing pairs of acoustic transmitter and receivers are mounted in a plane perpendicular to the well axis and are pressed onto the well wall. The acoustic wave emitted by the transmitters propagates in the fluid inside the well and the... View full abstract»

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  • Electric field induced piezoelectric response in ferroelectric materials near the paraelectric ferroelectric transition

    Publication Year: 1993, Page(s):525 - 528 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    In many ferroelectric materials, the piezoelectricity can be induced by an applied electric field and the material will return to piezoelectric inactive state when the field is reduced to zero. Based on thermodynamic theory, the effect of temperature and applied electric field on the electromechanical response is analyzed for materials with a first order and continuous ferroelectric-paraelectric p... View full abstract»

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  • Gas-coupled acoustic microscopy in the pulse-echo mode

    Publication Year: 1993, Page(s):667 - 671 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    We demonstrate the technical feasibility of a new scanning acoustic microscope (SAM) system. Unlike the traditional SAMs, which use liquids as couplants, the new system uses gases as couplants. To demonstrate that the new system can operate in the pulse-echo mode, we generated “dark-field” C-scans of the interior of solid objects at MHz frequencies. Previously, gas-coupled ultrasonic i... View full abstract»

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  • Time-resolved acoustic microscopy of short cracks

    Publication Year: 1993, Page(s):599 - 602 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Time-resolved acoustic microscopy has been used to measure the 3-dimensional profile of short cracks (70-200 μm surface length). In order to establish this technique the depth of short cracks in transparent materials were determined. This allows a comparison between the acoustic and direct optical measurements. Subsequently the depth of cracks and the growth of short fatigue cracks in Al-alloy ... View full abstract»

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  • Powder transportation by unidirectional ultrasound radiated from a pair of phase-shifted bending vibrators

    Publication Year: 1993, Page(s):457 - 461 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    In the present paper the mechanism of operation is studied for a new type of ultrasonic powder-transportation device proposed by the authors. The device consists of a pair of phase-shifted bending vibrators facing each other across a gap. The upper vibrator is laterally shifted relative to the lower one by a quarter-wavelength of the bending mode and the two vibrators are driven in temporal phases... View full abstract»

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