Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922698
N. Hall, F. Degertekin
Capacitive micromachined ultrasonic transducers (cMUTs) have so far relied on traditional detection methods where the capacitance change due to membrane deflection is measured under constant voltage. Sensitivity of this method is proportional to the frequency of the acoustic signal and the capacitance of the device. This limits the low-frequency operation and the maximum power output of the cMUTs. This paper describes an integrated optical detection method, which offers electrical isolation between transmit-receive electronics and displacement sensitivity independent of the gap thickness and acoustic frequency. These features alleviate the limitations on the transmit signal and DC bias levels. The method is demonstrated on a cMUT made of 1.3 /spl mu/m thick, 100 /spl mu/m diameter aluminum membranes fabricated on a fused quartz substrate. The aluminum back electrode of each membrane is shaped in the form of an optical diffraction grating. Thus the cMUT membrane and the diffraction fingers on the substrate form a phase sensitive diffraction grating. For displacement detection, the grating is illuminated through the quartz substrate by a laser and the intensity of reflected diffraction orders are monitored to provide the sensitivity of an optical interferometer. Displacement measurements on the cMUT array elements and ultrasonic pulse-echo experiments in air at 1.87 MHz are presented.
{"title":"An integrated optical detection method for capacitive micromachined ultrasonic transducers","authors":"N. Hall, F. Degertekin","doi":"10.1109/ULTSYM.2000.922698","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922698","url":null,"abstract":"Capacitive micromachined ultrasonic transducers (cMUTs) have so far relied on traditional detection methods where the capacitance change due to membrane deflection is measured under constant voltage. Sensitivity of this method is proportional to the frequency of the acoustic signal and the capacitance of the device. This limits the low-frequency operation and the maximum power output of the cMUTs. This paper describes an integrated optical detection method, which offers electrical isolation between transmit-receive electronics and displacement sensitivity independent of the gap thickness and acoustic frequency. These features alleviate the limitations on the transmit signal and DC bias levels. The method is demonstrated on a cMUT made of 1.3 /spl mu/m thick, 100 /spl mu/m diameter aluminum membranes fabricated on a fused quartz substrate. The aluminum back electrode of each membrane is shaped in the form of an optical diffraction grating. Thus the cMUT membrane and the diffraction fingers on the substrate form a phase sensitive diffraction grating. For displacement detection, the grating is illuminated through the quartz substrate by a laser and the intensity of reflected diffraction orders are monitored to provide the sensitivity of an optical interferometer. Displacement measurements on the cMUT array elements and ultrasonic pulse-echo experiments in air at 1.87 MHz are presented.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125965874","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922561
M. H. Badi, G. Yaralioglu, A. Sanli Ergun, F. Levent Degertekin, C. Cheng, B. Khuri-Yakub
Capacitive Micromachined Ultrasonic Transducers (cMUTs) are generally used to transmit and receive ultrasound in both air and water. These devices can be made on silicon and manufactured using standard CMOS processing techniques. When cMUTs are used in this way, significant effort is made to minimize energy loss into the substrate. If this loss is instead exploited so that the devices are optimized to couple energy into the silicon bulk, Lamb waves and Rayleigh waves are generated with high efficiency. These waves can then be detected using a similar device structure. With this method it is possible to fabricate Lamb wave devices on silicon using conventional integrated circuit processing techniques. This paper discusses the manufacturing and characterization of the first of these devices: a 1 MHz Lamb wave transducer that is fundamentally based on cMUT technology. The characterization of this device demonstrates that the energy coupled into the substrate results in a Lamb Wave where the lowest order anti-symmetric mode (A/sub 0/) is dominant. The insertion loss of this device in air is 43.06 dB.
{"title":"A first experimental verification of micromachined capacitive Lamb wave transducers","authors":"M. H. Badi, G. Yaralioglu, A. Sanli Ergun, F. Levent Degertekin, C. Cheng, B. Khuri-Yakub","doi":"10.1109/ULTSYM.2000.922561","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922561","url":null,"abstract":"Capacitive Micromachined Ultrasonic Transducers (cMUTs) are generally used to transmit and receive ultrasound in both air and water. These devices can be made on silicon and manufactured using standard CMOS processing techniques. When cMUTs are used in this way, significant effort is made to minimize energy loss into the substrate. If this loss is instead exploited so that the devices are optimized to couple energy into the silicon bulk, Lamb waves and Rayleigh waves are generated with high efficiency. These waves can then be detected using a similar device structure. With this method it is possible to fabricate Lamb wave devices on silicon using conventional integrated circuit processing techniques. This paper discusses the manufacturing and characterization of the first of these devices: a 1 MHz Lamb wave transducer that is fundamentally based on cMUT technology. The characterization of this device demonstrates that the energy coupled into the substrate results in a Lamb Wave where the lowest order anti-symmetric mode (A/sub 0/) is dominant. The insertion loss of this device in air is 43.06 dB.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124846181","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922670
Zong-qi Sun, Y. Mao, Wen‐hua Jiang, D. Zhang
Mode analysis of Lamb waves propagating in an aluminum alloyed pipe is carried out using wavelet transform (WT). With the aid of the technique the interaction of Lamb waves with a circumferential notch is investigated. It is found that different Lamb wave modes propagating in the pipe can be distinguished clearly by means of wavelet transformation. Therefore, the mode conversion caused by existence of the notch has been unambiguously observed.
{"title":"Investigation on interaction of Lamb waves and circumferential notch in pipe by means of wavelet transform","authors":"Zong-qi Sun, Y. Mao, Wen‐hua Jiang, D. Zhang","doi":"10.1109/ULTSYM.2000.922670","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922670","url":null,"abstract":"Mode analysis of Lamb waves propagating in an aluminum alloyed pipe is carried out using wavelet transform (WT). With the aid of the technique the interaction of Lamb waves with a circumferential notch is investigated. It is found that different Lamb wave modes propagating in the pipe can be distinguished clearly by means of wavelet transformation. Therefore, the mode conversion caused by existence of the notch has been unambiguously observed.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129367314","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922503
V. Yanchev, V.L. Strashilov
Surface transverse wave (STW) resonators exhibit substantial advantages over conventional SAW resonators. However, their analysis is more involved due to the complicated nature of the STW. Among a number of parameters the important Q-factor has faced serious difficulties. At present, none of the theoretical models is concerned with quantitative loss consideration and the establishment of reliable design rules is difficult. We present a theoretical study that permits us to conduct STW loss analysis and predict the resonator Q from the material and layout data. The coupling-of-modes (COM) transmission coefficient is derived by Floquet analysis. Its imaginary part is a measure of STW propagation loss that adds to grating reflection loss. As the overall loss is extremely sensitive to parameter choice, the full numerical search for the optimum design presently discussed can save considerable experimental effort.
{"title":"A study on the Q-factor of STW resonators by a COM theory","authors":"V. Yanchev, V.L. Strashilov","doi":"10.1109/ULTSYM.2000.922503","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922503","url":null,"abstract":"Surface transverse wave (STW) resonators exhibit substantial advantages over conventional SAW resonators. However, their analysis is more involved due to the complicated nature of the STW. Among a number of parameters the important Q-factor has faced serious difficulties. At present, none of the theoretical models is concerned with quantitative loss consideration and the establishment of reliable design rules is difficult. We present a theoretical study that permits us to conduct STW loss analysis and predict the resonator Q from the material and layout data. The coupling-of-modes (COM) transmission coefficient is derived by Floquet analysis. Its imaginary part is a measure of STW propagation loss that adds to grating reflection loss. As the overall loss is extremely sensitive to parameter choice, the full numerical search for the optimum design presently discussed can save considerable experimental effort.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129368487","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922506
E.L. Tan, Y. Chia
A rigorous analysis of surface acoustic wave tags for wireless identification (ID) systems is developed based on Green's function technique and method of moments. The SAW ID-tags can be fabricated using arbitrary finite reflector structures placed in multiple tracks and channels. From the Green's function solutions, the P matrix parameters for the reflector bits and coupling transducer are deduced. These P matrices are cascaded and interconnected using network analysis to account for the resulting quasi-2D structure. To provide more physical insights into the scattering mechanism, the cascaded network is described in terms of the more illuminating global reflection and transmission coefficients. Simulation of prototype SAW tag configuration is carried out. Response in time domain is presented to show the spurious signals due to multiple reflections.
{"title":"Green's function and network analysis of quasi-2D SAW ID-tags","authors":"E.L. Tan, Y. Chia","doi":"10.1109/ULTSYM.2000.922506","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922506","url":null,"abstract":"A rigorous analysis of surface acoustic wave tags for wireless identification (ID) systems is developed based on Green's function technique and method of moments. The SAW ID-tags can be fabricated using arbitrary finite reflector structures placed in multiple tracks and channels. From the Green's function solutions, the P matrix parameters for the reflector bits and coupling transducer are deduced. These P matrices are cascaded and interconnected using network analysis to account for the resulting quasi-2D structure. To provide more physical insights into the scattering mechanism, the cascaded network is described in terms of the more illuminating global reflection and transmission coefficients. Simulation of prototype SAW tag configuration is carried out. Response in time domain is presented to show the spurious signals due to multiple reflections.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130153327","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.921688
D. Leotta, J. Primozich, K. Beach, R. Bergelin, K. Gibson, D. Strandness
Vein grafts are placed to bypass diseased arteries in the lower limb when symptoms such as pain during walking, rest pain, and tissue necrosis occur. Frequent surveillance of these grafts is recommended since early detection and revision of stenoses improves the likelihood of long-term patency. We are using three-dimensional (3D) ultrasound imaging to measure progressive changes in vein graft geometry. Cross-sectional area measurements in planes normal to the vessel center axis are calculated from 3D surface reconstructions. Data sets from serial studies are registered in a common coordinate system using anatomical reference points and cross-sectional area measurements are compared at matched sites. Extended studies have tracked patients requiring surgical revision to enlarge the vessel lumen in stenotic regions of their grafts. Follow-up periods on 5 cases range from 30 to 79 weeks to date. Each revised graft segment demonstrated a decrease in cross-sectional area over time, ranging from 25% to 77%, averaged over the length of the revision. The sequential area measurements, combined with 3D surface displays, provide a record of remodeling patterns and rates at specific sites within the grafts.
{"title":"Cross-sectional area changes in peripheral vein grafts monitored by three-dimensional ultrasound imaging","authors":"D. Leotta, J. Primozich, K. Beach, R. Bergelin, K. Gibson, D. Strandness","doi":"10.1109/ULTSYM.2000.921688","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921688","url":null,"abstract":"Vein grafts are placed to bypass diseased arteries in the lower limb when symptoms such as pain during walking, rest pain, and tissue necrosis occur. Frequent surveillance of these grafts is recommended since early detection and revision of stenoses improves the likelihood of long-term patency. We are using three-dimensional (3D) ultrasound imaging to measure progressive changes in vein graft geometry. Cross-sectional area measurements in planes normal to the vessel center axis are calculated from 3D surface reconstructions. Data sets from serial studies are registered in a common coordinate system using anatomical reference points and cross-sectional area measurements are compared at matched sites. Extended studies have tracked patients requiring surgical revision to enlarge the vessel lumen in stenotic regions of their grafts. Follow-up periods on 5 cases range from 30 to 79 weeks to date. Each revised graft segment demonstrated a decrease in cross-sectional area over time, ranging from 25% to 77%, averaged over the length of the revision. The sequential area measurements, combined with 3D surface displays, provide a record of remodeling patterns and rates at specific sites within the grafts.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132488416","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.921646
E. Radulescu, P. A. Lewin, A. Goldstein, Andrzej Nowicki
The spatial averaging model was developed and experimentally verified in the frequency range 1-40 MHz. The model is applicable to focused sources of circular geometry, accounts for the effects of hydrophone finite aperture and allows calibration by substitution to be performed when the active elements of reference and tested hydrophone differ significantly. The effective diameters of the ultrasonic hydrophone probes calibrated in the focal plane of the sources with different f-numbers ranged from 150-500 /spl mu/m. The probes with diameters smaller than that of the reference hydrophone exhibited experimentally determined absolute sensitivity higher than the true one. The model was capable of predicting the correct sensitivity with an overall uncertainty of +1 dB. It is now being extended to be applicable to frequencies beyond 40 MHz and rectangular acoustic sources.
{"title":"Hydrophone spatial averaging corrections from 1-40 MHz","authors":"E. Radulescu, P. A. Lewin, A. Goldstein, Andrzej Nowicki","doi":"10.1109/ULTSYM.2000.921646","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921646","url":null,"abstract":"The spatial averaging model was developed and experimentally verified in the frequency range 1-40 MHz. The model is applicable to focused sources of circular geometry, accounts for the effects of hydrophone finite aperture and allows calibration by substitution to be performed when the active elements of reference and tested hydrophone differ significantly. The effective diameters of the ultrasonic hydrophone probes calibrated in the focal plane of the sources with different f-numbers ranged from 150-500 /spl mu/m. The probes with diameters smaller than that of the reference hydrophone exhibited experimentally determined absolute sensitivity higher than the true one. The model was capable of predicting the correct sensitivity with an overall uncertainty of +1 dB. It is now being extended to be applicable to frequencies beyond 40 MHz and rectangular acoustic sources.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130950849","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922649
M. Doxbeck, M. A. Hussain, J. Frankel, A. Abbate
The intent of this work is to obtain creeping longitudinal wave (P wave) delays due to residual stresses on a known specimen and thus to study the procedures for obtaining residual stresses by laser ultrasonics.
{"title":"Use of laser generated creeping longitudinal waves to determine residual stresses","authors":"M. Doxbeck, M. A. Hussain, J. Frankel, A. Abbate","doi":"10.1109/ULTSYM.2000.922649","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922649","url":null,"abstract":"The intent of this work is to obtain creeping longitudinal wave (P wave) delays due to residual stresses on a known specimen and thus to study the procedures for obtaining residual stresses by laser ultrasonics.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127967374","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922644
F. Vander Meulen, G. Feuillard, O. Bou Matar, L. Tran Huu Hue, M. Lethiecq
Using multiple scattering theories, the influence of granular distribution on acoustic phase velocity in particle-loaded liquids was studied. Theoretical results were compared to measurements in suspensions of acrylic spheres in ethylene glycol. It appears that the phase velocity versus frequency shows a minimum, the position and sharpness of which are related to the mean diameter of particles and to the standard deviation of the diameter distribution. Its amplitude is only influenced by the concentration. Therefore, it is shown that granulometric properties of suspensions can be determined by an ultrasonic method, through the behavior of phase velocity versus frequency.
{"title":"Application of multiple scattering theories to the evaluation of granular distributions based on phase velocity measurements","authors":"F. Vander Meulen, G. Feuillard, O. Bou Matar, L. Tran Huu Hue, M. Lethiecq","doi":"10.1109/ULTSYM.2000.922644","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922644","url":null,"abstract":"Using multiple scattering theories, the influence of granular distribution on acoustic phase velocity in particle-loaded liquids was studied. Theoretical results were compared to measurements in suspensions of acrylic spheres in ethylene glycol. It appears that the phase velocity versus frequency shows a minimum, the position and sharpness of which are related to the mean diameter of particles and to the standard deviation of the diameter distribution. Its amplitude is only influenced by the concentration. Therefore, it is shown that granulometric properties of suspensions can be determined by an ultrasonic method, through the behavior of phase velocity versus frequency.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131336251","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}
Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.921494
G. Yang, W. Ren, S-F. Liu, A. Masys, B. K. Mukherjee
We have measured some of the dielectric, elastic, and piezoelectric constants of several types of PZT piezoelectric ceramics, manufactured by EDO Corporation, as a function of applied electric field and mechanical stress. Both the high frequency impedance resonance method and the low frequency response of the material under electrical and mechanical excitations were employed to determine these constants. We present the dependence of these material constants on an applied DC bias voltage and on an applied mechanical stress. Most of the results can be understood on the basis of the extrinsic contributions to the piezoelectric response that arises from the existence of domains in the materials.
{"title":"Effects of uniaxial stress and DC bias field on the piezoelectric, dielectric, and elastic properties of piezoelectric ceramics","authors":"G. Yang, W. Ren, S-F. Liu, A. Masys, B. K. Mukherjee","doi":"10.1109/ULTSYM.2000.921494","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921494","url":null,"abstract":"We have measured some of the dielectric, elastic, and piezoelectric constants of several types of PZT piezoelectric ceramics, manufactured by EDO Corporation, as a function of applied electric field and mechanical stress. Both the high frequency impedance resonance method and the low frequency response of the material under electrical and mechanical excitations were employed to determine these constants. We present the dependence of these material constants on an applied DC bias voltage and on an applied mechanical stress. Most of the results can be understood on the basis of the extrinsic contributions to the piezoelectric response that arises from the existence of domains in the materials.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125452178","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}
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