1996 IEEE Ultrasonics Symposium. Proceedings最新文献

{"title":"SAW devices as wireless passive sensors","authors":"Leonhard Reindl, Gerd Scholl, T. Ostertag, C. Ruppel, W. Bulst, Franz Seifert","doi":"10.1109/ULTSYM.1996.583993","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.583993","url":null,"abstract":"Surface acoustic wave (SAW) radio sensors make it possible to read measurement values from a remote location. The decisive advantage of these SAW sensors lies in their passive operation with no need for a separate power supply, and in the possibility of wireless installation at particularly inaccessible locations. The passive SAW sensors are maintenance free. The physical or chemical properties that shall be detected change the propagation characteristics of the SAW. In this paper we compare the sensitivity of different types of SAW sensors. These are resonators, reflective delay lines, and dispersive structures. Examples for several applications are presented.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"223 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114469811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vorticity measurements with an acoustic time-reversal mirror","authors":"P. Roux, M. Fink","doi":"10.1109/ULTSYM.1996.584221","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584221","url":null,"abstract":"Time-reversal invariance for acoustic propagation is broken when the propagating medium contains a flow. The authors take advantage of the violation of this symmetry to achieve a new way of characterizing the vorticity field of a flow with a double time-reversal mirror (TRM). The double TRM is made up of 2 arrays of piezo-electric transducers placed in front of each other and on either side of the flow. The time-reversal process is performed between the 2 arrays: when 1 array emits, the other 1 receives, time-reverses and re-emits the acoustic wave. In the presence of a flow, the acoustic wavefront is distorted at a crossing through the flow. However this distortion is related to the amplitude and size of the vorticity field of the flow and is often too small to be observed experimentally after 1 crossing. In order to amplify this wavefront distortion, the authors make the acoustic wave do several round trips through the flow between the 2 arrays. The greater number of crossings through the vorticity field induces an amplification of the effect of vorticity on the acoustic wavefront. This effect can then be easily measured and allows the authors to characterize vorticity even for small vorticity fields.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114499720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resonant acoustooptic interaction mechanisms in materials with broadened absorption line","authors":"A.V. Gierus, V. Chesnokov, V. V. Proklov","doi":"10.1109/ULTSYM.1996.584123","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584123","url":null,"abstract":"The comparative consideration of efficiencies for all possible mechanisms of acousto-optic interaction in resonant photoelastic structures on base of AlGaInAs is carried out. It is found that the most effective mechanism is the resonant one due to a potential deformation interaction of two-dimensional excitons in multiquantum wells (MQW). Calculation of characteristic photoelastic constants for a general situation with different broadened absorption lines of an exciton resonance is carried out. Some peculiarities of photoelastic resonance under influence of both homogeneous and inhomogeneous line broadening are firstly established and explained.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116278703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of the blood velocity spectrum using a recursive lattice filter","authors":"J. Jensen, C. Buelund, A. Jorgensen, P. Munk","doi":"10.1109/ULTSYM.1996.584210","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584210","url":null,"abstract":"In medical ultrasound the blood velocity distribution in a vessel can be found by emitting a pulsed field into the patient. The field is then scattered by the tissues and the red blood cells, and a single complex sample set is acquired at the depth of interest for each pulse emitted. The signals acquired for showing the blood velocity distribution are inherently non-stationary, due to the pulsatility of the flow. All current signal processing schemes assume that the signal is stationary within the window of analysis, although this is an approximation. In this paper a recursive least-squares lattice filter is used for finding a parametric model for the velocity distribution. A new set of complex coefficients is calculated for each point in time, and it is thus possible to track the non-stationary properties of the stochastic velocity signal. The dynamic characteristics of the non-stationarity are incorporated through an exponential decay factor, that sets the exponential horizon of the filter. A factor close to 1 gives a long horizon with low variance estimates, but can not track a highly non-stationary flow. Setting the factor is therefore a compromise between estimate variance and the filter's dynamic adaptation. Using a lattice filter gives a structure that is easy and robust, when implemented with fixed point arithmetic. The procedure has been tested on both simulated and in-vivo data, and gives spectral estimates quite different from the normal FFT approach. Synthetic data were generated based on the measured time evolution of the spatial mean velocity in the femoral artery. The smooth theoretical velocity distribution is then known and can be compared to the estimated distribution. Using 8 parameters a very smooth estimate of the velocity distribution is seen, more in line with the actual distributions that always will be smooth. Setting the exponential decay factor to 0.99 gives satisfactory results for in-vivo data from the carotid artery. The filter can easily be implemented using a standard fixed-point signal processing chip for real-time processing.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"393 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116392641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An ultrasonic flow meter for industrial applications using a helical sound path","authors":"T. Vontz, V. Magori","doi":"10.1109/ULTSYM.1996.584171","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584171","url":null,"abstract":"A new ultrasonic measuring tube principle is presented which is usable for a wide range of tube diameters. The measuring device consists of a square tube in which two transducers and two special reflectors me mounted. In addition to these special reflectors, three wall reflections are used to form a helical sound path which integrates the flow independently from the fluid flow profile. The fluid velocity is derived from the difference in travel time between up and down stream travelling wave packets. In order to gain a measurement accuracy (linearity) of /spl plusmn/1% in a velocity range of 1:100, aspects of body sound, reflectional and zero flow effects must be taken into account. The progress gained by the new measuring principle is discussed on the basis of simulation and experimental investigations. Results are presented for different temperatures and over a wide range of flow velocities. The potential applications comprise flow measurement of liquids in the industry as well as heat metering in hot water supply.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117000209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of surface impedance approach to ultrasonic wave propagation in layered anisotropic media","authors":"F. Levent Degertekin, B. Honein, B. Khuri-Yakub","doi":"10.1109/ULTSYM.1996.584044","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584044","url":null,"abstract":"Matrix methods have been extensively used for wave propagation problems in layered media. Direct application of these methods using partial waves or transfer matrix formulation result in numerical problems known as exponential dichotomy. In this paper, we use the concept of surface impedance tensor to tackle this problem. Given the surface impedance tensor along an initial surface, a recursive algorithm is used to calculate the surface impedance tensor for the other layers. The methodology inherently prevents exponential dichotomy. We present applications of the surface impedance approach to practical problems. As examples, we consider the anisotropy of SAW velocity for different electrical boundary conditions, plane wave reflection from immersed layered structures with general anisotropy, and internal field distributions for predicting defect detection sensitivity.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"55 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120868778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NDE of a subsurface defect in a magnetic disk head and surface defects fabricated on metal plate by photoacoustic microscopy","authors":"T. Hoshimiya, H. Endoh, Y. Hiwatashi","doi":"10.1109/ULTSYM.1996.584113","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584113","url":null,"abstract":"In this paper, three independent contributions on NDE of subsurface and surface defects with the same photoacoustic microscope (PAM) are summarized. The PAM of this research uses optical scanners for beam scanning. The only difference is that a compact closed type PA cell is used in NDE of magnetic disk heads, whereas a quasi-open type large PA cell is used in the other two experiments. A crack in a ferrite region and a bubble in a glass filler of a magnetic head are observed with the PAM with a resolution of up to 2 micrometers. Photoacoustic (PA) imaging of closely located surface defects fabricated on a metal plate clearly reflects depth information of individual defects. PA signal intensities of simulated pitting corrosions fabricated on a metal plate vary with both depth and diameters of holes. The characteristics are interpreted with a simple model where PA signal is proportional to a surface area exposed to a laser beam.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123949018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiphase pipe flow velocity profile measurements by Doppler ultrasound containing a high level of colored noise","authors":"J. Remeniéras, S. Kouame, J. Grégoire, P. Jaraczewski, F. Patat","doi":"10.1109/ULTSYM.1996.584055","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.584055","url":null,"abstract":"This paper presents an application of continuous wave Doppler ultrasound measurement to two phase flow in pipes. A specific Doppler system has been developed for this purpose. The presence of strong colored noise in the experimental Doppler signals was an incentive to use a complex UDV/sup H/ factored form of the instrumental variable identification technique. Direct Doppler frequency estimation is then obtained using the argument poles of the autoregressive model which identifies the Doppler part of the signal. The performed tests with a complex parametric theoretical model, simulated and experimental Doppler signals have demonstrated the superiority of this adaptive signal processing method compared with the UDU/sup H/ factored form of the recursive least square autoregressive identification algorithm.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124820899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface acoustic wave channel waveguides by AlN films","authors":"K. Giannelli, L. Giovannini, E. Verona, G. Socino","doi":"10.1109/ULTSYM.1996.583976","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.583976","url":null,"abstract":"Surface acoustic wave (SAW) channel waveguides have been fabricated by sputtering deposition of AlN films on YX- and XY-LiNbO/sub 3/ substrates. Since the SAW phase velocity is higher in AlN than in the substrate, the supported film acts as a cladding for the guide, while the unmodified substrate corresponds to the core. Both single channel and two-channel waveguides in the configuration of an acoustic coupler have been investigated. Measurement of the acoustic field in the guiding structures has been done by use of acoustooptic probing techniques. The guiding properties of the guides have been probed at different distances from the transducer. In the case of two-channel waveguides the coupling length for the fundamental mode has been measured for different guide separation distances.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128268645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"General-purpose simulator for leaky surface acoustic wave devices based on coupling-of-modes theory","authors":"K. Hashimoto, H. Yamaguchi","doi":"10.1109/ULTSYM.1996.583819","DOIUrl":"https://doi.org/10.1109/ULTSYM.1996.583819","url":null,"abstract":"The paper describes the development of a general-purpose simulator for high performance leaky surface acoustic wave (LSAW) devices. The derivation of the coupling-of-modes (COM) parameters for the simulator is based on a method developed originally for surface transverse wave devices: the method can skillfully takes the effect of back-scattered bulk acoustic waves into consideration. All the COM parameters for the analysis are determined as a function of electrode thickness, and the simulation itself is carried out in exactly the same may with the conventional COM analysis. A ladder-type LSAW filter on 36/spl deg/YX-LiTaO/sub 3/ and an interdigitated-interdigital transducer type filter employing longitudinal-type LSAWs on (011)-Li/sub 2/B/sub 4/O/sub 7/ are analysed, which concludes how effectively the developed simulator is applicable to assessing LSAW device performances, present simulator is demonstrated.","PeriodicalId":278111,"journal":{"name":"1996 IEEE Ultrasonics Symposium. Proceedings","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127062388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}