Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663021
M. Kadota
A good temperature coefficient of frequency (TCF) and an appropriate electromechanical coupling factor (k/sub s/) are required for applications of surface acoustic wave (SAW) devices requiring a specific bandwidth. An ST cut X propagation quartz substrate for Rayleigh SAW devices is known for its good TCF; however, its electromechanical coupling factor is as small as 0.0014 at k/sub s//sup 2/, so it is often unsuitable for applications of SAW devices requiring a specific bandwidth. Generally, most single crystals and thin films have a negative TCF. Only a few materials such as a quartz substrate having a specific cutting angle or a propagating direction and SiO/sub 2/ films have a positive TCF. Many investigations aimed at improving the TCF by depositing a SiO/sub 2/ film having a positive TCF on a substrate having a negative TCF have been reported on. However, since the absolute value of the TCF of such substrates is large, a relatively thick film of SiO/sub 2/ is required for compensation of its TCF. The author has theoretically and experimentally studied in detail the opposite combination, that is, the combination of a ZnO film having a negative TCF and a quartz substrate having an appropriate positive TCF, with selection of appropriate cutting and propagation angles of the substrate. As the result, the author could realize SAW substrates having an appropriate electromechanical coupling factor (k/sub s//sup 2/=0.011), a good TCF (/spl ap/Oppm//spl deg/C), and a zero power flow angle in structures of IDT/ZnO/quartz and IDT/ZnO/shorted-plane/quartz using an ST-cut 35/spl deg/X propagation quartz substrates (a 29/spl deg/45' rotated Y and a 42/spl deg/45' rotated Y plates 35/spl deg/X propagation quartz) for the first time.
{"title":"Combination of ZnO film and quartz to realize large coupling factor and excellent temperature coefficient for SAW devices","authors":"M. Kadota","doi":"10.1109/ULTSYM.1997.663021","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663021","url":null,"abstract":"A good temperature coefficient of frequency (TCF) and an appropriate electromechanical coupling factor (k/sub s/) are required for applications of surface acoustic wave (SAW) devices requiring a specific bandwidth. An ST cut X propagation quartz substrate for Rayleigh SAW devices is known for its good TCF; however, its electromechanical coupling factor is as small as 0.0014 at k/sub s//sup 2/, so it is often unsuitable for applications of SAW devices requiring a specific bandwidth. Generally, most single crystals and thin films have a negative TCF. Only a few materials such as a quartz substrate having a specific cutting angle or a propagating direction and SiO/sub 2/ films have a positive TCF. Many investigations aimed at improving the TCF by depositing a SiO/sub 2/ film having a positive TCF on a substrate having a negative TCF have been reported on. However, since the absolute value of the TCF of such substrates is large, a relatively thick film of SiO/sub 2/ is required for compensation of its TCF. The author has theoretically and experimentally studied in detail the opposite combination, that is, the combination of a ZnO film having a negative TCF and a quartz substrate having an appropriate positive TCF, with selection of appropriate cutting and propagation angles of the substrate. As the result, the author could realize SAW substrates having an appropriate electromechanical coupling factor (k/sub s//sup 2/=0.011), a good TCF (/spl ap/Oppm//spl deg/C), and a zero power flow angle in structures of IDT/ZnO/quartz and IDT/ZnO/shorted-plane/quartz using an ST-cut 35/spl deg/X propagation quartz substrates (a 29/spl deg/45' rotated Y and a 42/spl deg/45' rotated Y plates 35/spl deg/X propagation quartz) for the first time.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75542425","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663000
X. Tong, D. Zhang, Y. Li, Y. Shui
The high frequency SAW transducers have shown great vitality in mobile phone and satellite communications and so on. One of the important ways to raise the working frequency and keeping the size of strips unchanged is to utilize the SAW devices based on high velocity acoustic wave modes. Therefore, the investigation of quasi-longitudinal acoustic surface leaky waves (QLASLWs) is of great significant because of its potential applications. Both theoretical and experimental results on LiNbO/sub 3/ and quartz are shown in this paper, for example, on LiNbO/sub 3/ in the range of Euler angles (0/spl deg/, /spl beta/, 90/spl deg/), the theoretical velocities are between 6000 m/s and 7000 m/s, nearly about twice that of normal surface waves, but the piezoelectric coupling coefficients varies between about 0.14% to 0.5%, much less than that of surface waves. The experimental results, for example, on LiNbO/sub 3/ at Euler angle (0/spl deg/, 38/spl deg/, 90/spl deg/), shows well agreement with the theoretical results. The theoretical results on quartz in the range of Euler angle (0/spl deg/, 124/spl deg/, /spl gamma/) are also shown in this paper.
{"title":"Investigation of longitudinal leaky surface acoustic wave on lithium niobate and quartz","authors":"X. Tong, D. Zhang, Y. Li, Y. Shui","doi":"10.1109/ULTSYM.1997.663000","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663000","url":null,"abstract":"The high frequency SAW transducers have shown great vitality in mobile phone and satellite communications and so on. One of the important ways to raise the working frequency and keeping the size of strips unchanged is to utilize the SAW devices based on high velocity acoustic wave modes. Therefore, the investigation of quasi-longitudinal acoustic surface leaky waves (QLASLWs) is of great significant because of its potential applications. Both theoretical and experimental results on LiNbO/sub 3/ and quartz are shown in this paper, for example, on LiNbO/sub 3/ in the range of Euler angles (0/spl deg/, /spl beta/, 90/spl deg/), the theoretical velocities are between 6000 m/s and 7000 m/s, nearly about twice that of normal surface waves, but the piezoelectric coupling coefficients varies between about 0.14% to 0.5%, much less than that of surface waves. The experimental results, for example, on LiNbO/sub 3/ at Euler angle (0/spl deg/, 38/spl deg/, 90/spl deg/), shows well agreement with the theoretical results. The theoretical results on quartz in the range of Euler angle (0/spl deg/, 124/spl deg/, /spl gamma/) are also shown in this paper.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72935632","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663031
V.N. Kurskii, V. V. Proklov
The new architecture of a spread spectrum code-time division multiple access mobile communication system radiointerface (CTDMA) based on surface acoustic wave (SAW) and planar acousto-optics (AO) components is firstly developed in accordance with the Universal Mobile Telecommunication System (UMTS) requirements.
{"title":"Advanced mobile communications radiointerface (CTDMA) architecture based on SAW components","authors":"V.N. Kurskii, V. V. Proklov","doi":"10.1109/ULTSYM.1997.663031","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663031","url":null,"abstract":"The new architecture of a spread spectrum code-time division multiple access mobile communication system radiointerface (CTDMA) based on surface acoustic wave (SAW) and planar acousto-optics (AO) components is firstly developed in accordance with the Universal Mobile Telecommunication System (UMTS) requirements.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74078687","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661855
A. R. Brenner, K. Eck, W. Wilhelm, T. Noll
The authors present a depth-dependent mismatched-filter pulse compression technique which improves range resolution and dynamic range of coded excitation ultrasonic imaging compared to a matched-filter pulse compression. After choosing a suitable magnitude spectrum, frequency weighting is used to design the appropriate mismatched filter depth-dependently, which allows to control mainlobe width and sidelobe characteristics. Both simulations and measurements are used to demonstrate the efficacy of the technique. A VLSI implementation of a depth-dependent mismatched filter is shown to be feasible.
{"title":"Improved resolution and dynamic range in medical ultrasonic imaging using depth-dependent mismatched filtering","authors":"A. R. Brenner, K. Eck, W. Wilhelm, T. Noll","doi":"10.1109/ULTSYM.1997.661855","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661855","url":null,"abstract":"The authors present a depth-dependent mismatched-filter pulse compression technique which improves range resolution and dynamic range of coded excitation ultrasonic imaging compared to a matched-filter pulse compression. After choosing a suitable magnitude spectrum, frequency weighting is used to design the appropriate mismatched filter depth-dependently, which allows to control mainlobe width and sidelobe characteristics. Both simulations and measurements are used to demonstrate the efficacy of the technique. A VLSI implementation of a depth-dependent mismatched filter is shown to be feasible.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84468528","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663104
A. Calabro, C. Esposito, A. Lizza, M. Giordano, S. Tedesco, A. D’Amore, L. Nicolais
A new acoustic emission failure mode analysis methodology for composite materials was developed. A single carbon fiber composite based on a polyester matrix has been used as a simple model. Fiber breakage during tensile loading tests was observed by using a polarized light microscope and simultaneously detected by a resonant acoustic probe. The resonant probe was used as a trigger for recording the fiber failure events. Single acoustic emission events from a wide band probe were recorded for fast Fourier transform analysis. The single fiber specimen, having an unique failure mode, presents advantages for standardization of AE techniques for quantitative analysis of failures in polymer composite materials. The same procedure can be exploited to investigate the other failure modes, namely fiber-matrix debonding and matrix cracking.
{"title":"A frequency spectral analysis of the fiber failure acoustic emission signal in a single fiber composite","authors":"A. Calabro, C. Esposito, A. Lizza, M. Giordano, S. Tedesco, A. D’Amore, L. Nicolais","doi":"10.1109/ULTSYM.1997.663104","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663104","url":null,"abstract":"A new acoustic emission failure mode analysis methodology for composite materials was developed. A single carbon fiber composite based on a polyester matrix has been used as a simple model. Fiber breakage during tensile loading tests was observed by using a polarized light microscope and simultaneously detected by a resonant acoustic probe. The resonant probe was used as a trigger for recording the fiber failure events. Single acoustic emission events from a wide band probe were recorded for fast Fourier transform analysis. The single fiber specimen, having an unique failure mode, presents advantages for standardization of AE techniques for quantitative analysis of failures in polymer composite materials. The same procedure can be exploited to investigate the other failure modes, namely fiber-matrix debonding and matrix cracking.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85403960","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661777
M. L. Wicks, H. Sun, M. Russell, S. Neal, E. Boote, L. J. Anglo, G. Ross, T. Loy
Results are presented from an ongoing project at the University of Missouri-Columbia (MU) which focuses on the detection, grading, and staging of prostate cancer. The study addressed in this paper was performed in vitro using human prostates obtained from radical prostatectomies. Each prostate was transversely sectioned to extract a 2 mm slice which was then ultrasonically scanned. Cancerous and benign regions of the prostate were subsequently identified on the tissue slice by a pathologist. This scanning and analysis procedure allowed for a one-to-one correlation of actual tissue histopathology and acoustic parameter images. Echogenicity and differential echogenicity measures were calculated based on integrated backscatter, backscattered power spectra, and backscatter coefficient. Of these measures, only the backscatter coefficient, which was corrected for spatial variations in attenuation, showed a statistically significant trend with cancer grade. This trend suggests a new result which is that the inherent echogenicity of cancerous tissue decreases with increasing cancer grade.
{"title":"In vitro correlation of echogenicity and differential echogenicity with human prostate cancer grade","authors":"M. L. Wicks, H. Sun, M. Russell, S. Neal, E. Boote, L. J. Anglo, G. Ross, T. Loy","doi":"10.1109/ULTSYM.1997.661777","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661777","url":null,"abstract":"Results are presented from an ongoing project at the University of Missouri-Columbia (MU) which focuses on the detection, grading, and staging of prostate cancer. The study addressed in this paper was performed in vitro using human prostates obtained from radical prostatectomies. Each prostate was transversely sectioned to extract a 2 mm slice which was then ultrasonically scanned. Cancerous and benign regions of the prostate were subsequently identified on the tissue slice by a pathologist. This scanning and analysis procedure allowed for a one-to-one correlation of actual tissue histopathology and acoustic parameter images. Echogenicity and differential echogenicity measures were calculated based on integrated backscatter, backscattered power spectra, and backscatter coefficient. Of these measures, only the backscatter coefficient, which was corrected for spatial variations in attenuation, showed a statistically significant trend with cancer grade. This trend suggests a new result which is that the inherent echogenicity of cancerous tissue decreases with increasing cancer grade.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81668600","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663341
N. Bourriot, Sylvain Ballandras, W. Steichen, P. Maitre, B. Piwakowski, J. Gelly, B. Piranda, R. Muksch
Advances in microtechnology reinforce the interest in the development of miniaturized transducers for endoscopic imaging applications. The present work is devoted to the design and fabrication of miniaturized annular array transducer. A first design of the transducer has been performed using an analysis of the radiated pressure in a semi-infinite liquid based on a time-domain computation (DREAM program). The selected structure has been then simulated using an harmonic FEA taking piezoelectricity and material losses into account. A simplified boundary condition based on a plane wave radiation condition was used to simulate the immersed regime of the transducer. However, this approach allows one to estimate the pressure at the radiation surface of the transducer which can be used to improve the calculation of the acoustic pressure distribution in the liquid. The results of this design approach can be used to fabricate a test structure using ultrasound micromachining techniques adapted to sub-millimeter structure applications (resolution in the range 50 microns, machining depth close to 1 mm). A 2 mm diameter annular PZT structure has been built and tested. Theoretical and experimental results concerning the admittance of the annular array are compared. Design consideration for the fabrication of the 1.2 mm diameter transducer are exposed and discussed.
{"title":"Design and fabrication of a miniaturized annular array","authors":"N. Bourriot, Sylvain Ballandras, W. Steichen, P. Maitre, B. Piwakowski, J. Gelly, B. Piranda, R. Muksch","doi":"10.1109/ULTSYM.1997.663341","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663341","url":null,"abstract":"Advances in microtechnology reinforce the interest in the development of miniaturized transducers for endoscopic imaging applications. The present work is devoted to the design and fabrication of miniaturized annular array transducer. A first design of the transducer has been performed using an analysis of the radiated pressure in a semi-infinite liquid based on a time-domain computation (DREAM program). The selected structure has been then simulated using an harmonic FEA taking piezoelectricity and material losses into account. A simplified boundary condition based on a plane wave radiation condition was used to simulate the immersed regime of the transducer. However, this approach allows one to estimate the pressure at the radiation surface of the transducer which can be used to improve the calculation of the acoustic pressure distribution in the liquid. The results of this design approach can be used to fabricate a test structure using ultrasound micromachining techniques adapted to sub-millimeter structure applications (resolution in the range 50 microns, machining depth close to 1 mm). A 2 mm diameter annular PZT structure has been built and tested. Theoretical and experimental results concerning the admittance of the annular array are compared. Design consideration for the fabrication of the 1.2 mm diameter transducer are exposed and discussed.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84176026","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661781
K. Harasiewicz, H. Gahunia, C. Lemaire, N. Konyer, H.K.W. Kim, P. Babyn, K. Pritzker, F. Foster
A system based on reconstituted articular cartilage is used to facilitate evaluation of noninvasive imaging methods such as ultrasound biomicroscopy (UBM) and magnetic resonance imaging (MRI) for assessment of osteoarthritis (OA). Chondrocytes from the superficial and deep layers of calf articular cartilage were isolated and cultured. Some cultures were treated with interleukin 1 (Il-1) and the effects on cartilage growth were studied. On days 21, 35, and 56 the cartilage cultures were examined using UBM, MRI, and histology. Cartilage thickness measured using UBM, MRI, and histology were similar with the correlation coefficients of 0.982 (P<0.0001) and 0.998 (P<0.0001) respectively. Comparisons of the UBM images with histology and MRI are presented and potential application of the real time UBM imaging of cartilage is discussed.
{"title":"Ultrasound biomicroscopy and magnetic resonance imaging of reconstituted articular cartilage","authors":"K. Harasiewicz, H. Gahunia, C. Lemaire, N. Konyer, H.K.W. Kim, P. Babyn, K. Pritzker, F. Foster","doi":"10.1109/ULTSYM.1997.661781","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661781","url":null,"abstract":"A system based on reconstituted articular cartilage is used to facilitate evaluation of noninvasive imaging methods such as ultrasound biomicroscopy (UBM) and magnetic resonance imaging (MRI) for assessment of osteoarthritis (OA). Chondrocytes from the superficial and deep layers of calf articular cartilage were isolated and cultured. Some cultures were treated with interleukin 1 (Il-1) and the effects on cartilage growth were studied. On days 21, 35, and 56 the cartilage cultures were examined using UBM, MRI, and histology. Cartilage thickness measured using UBM, MRI, and histology were similar with the correlation coefficients of 0.982 (P<0.0001) and 0.998 (P<0.0001) respectively. Comparisons of the UBM images with histology and MRI are presented and potential application of the real time UBM imaging of cartilage is discussed.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84080102","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663050
V. Anisimkin, S. Maximov, P. Verardi, E. Verona
Adsorption of water vapors on single crystal and polycrystalline substrates is analyzed using the propagation of surface acoustic waves as an experimental tool. The perturbation in the SAW velocity (/spl Delta/v/v/sub 0/), the number N of adsorbed species as well as the changes in the density /spl Delta//spl rho///spl rho/ and in the elastic moduli /spl Delta/c/sub ij//c/sub ij/ of the sorbent materials, are deduced in terms of the normalized SAW displacements A/sub x/, A/sub y/, A/sub z/ and of the unperturbed SAW velocity v/sub 0/. Vapour adsorption on polished plates of single crystal quartz and polycrystalline films of Pd and Pd:Ni is experimentally investigated. Results of the measurements clearly show that humidity adsorption gives rise to effects whose amplitude is larger and whose time duration is longer in the films than in the plates. These effects are also dependent on the orientation of the quartz, allowing to monitor the value and the rate of the effect by proper selection of a substrate material.
{"title":"Effect of humidity on SAW devices","authors":"V. Anisimkin, S. Maximov, P. Verardi, E. Verona","doi":"10.1109/ULTSYM.1997.663050","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663050","url":null,"abstract":"Adsorption of water vapors on single crystal and polycrystalline substrates is analyzed using the propagation of surface acoustic waves as an experimental tool. The perturbation in the SAW velocity (/spl Delta/v/v/sub 0/), the number N of adsorbed species as well as the changes in the density /spl Delta//spl rho///spl rho/ and in the elastic moduli /spl Delta/c/sub ij//c/sub ij/ of the sorbent materials, are deduced in terms of the normalized SAW displacements A/sub x/, A/sub y/, A/sub z/ and of the unperturbed SAW velocity v/sub 0/. Vapour adsorption on polished plates of single crystal quartz and polycrystalline films of Pd and Pd:Ni is experimentally investigated. Results of the measurements clearly show that humidity adsorption gives rise to effects whose amplitude is larger and whose time duration is longer in the films than in the plates. These effects are also dependent on the orientation of the quartz, allowing to monitor the value and the rate of the effect by proper selection of a substrate material.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80227534","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663091
P. Eccardt, H. Landes, R. Lerch
The interaction between acoustic wave propagation and a fluid in motion can be described by a system of coupled equations. For many applications like ultrasound flowmeters, medical ultrasound diagnostics, environmental acoustics or air conditioning systems, the influence of the acoustic waves upon the flow can be neglected. This allows a separation and therefore a successive solution of the problem. The results of finite element (FEM) simulations based on a modified wave equation with the flow profile as a boundary condition have been previously presented. In this paper, a new boundary element (BEM) technique is reported to solve this problem. One major advantage over FEM is the reduced dimension of the problem, leading to easier meshing and, especially for unbounded domains, to reduced computational effort. For the new BEM approach the Green's function had to be modified to consider flow. Based on an approximate Green's function a boundary element solution was developed. This new approach is compared with the previously implemented FEM scheme as well as with experiments measuring the sound pressure in a flow channel for various geometries and flow profiles. The results show good agreement between experiment and simulation. The limitations of this approach will be discussed.
{"title":"Boundary element solutions for acoustic wave propagation in media with nonuniform flow","authors":"P. Eccardt, H. Landes, R. Lerch","doi":"10.1109/ULTSYM.1997.663091","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663091","url":null,"abstract":"The interaction between acoustic wave propagation and a fluid in motion can be described by a system of coupled equations. For many applications like ultrasound flowmeters, medical ultrasound diagnostics, environmental acoustics or air conditioning systems, the influence of the acoustic waves upon the flow can be neglected. This allows a separation and therefore a successive solution of the problem. The results of finite element (FEM) simulations based on a modified wave equation with the flow profile as a boundary condition have been previously presented. In this paper, a new boundary element (BEM) technique is reported to solve this problem. One major advantage over FEM is the reduced dimension of the problem, leading to easier meshing and, especially for unbounded domains, to reduced computational effort. For the new BEM approach the Green's function had to be modified to consider flow. Based on an approximate Green's function a boundary element solution was developed. This new approach is compared with the previously implemented FEM scheme as well as with experiments measuring the sound pressure in a flow channel for various geometries and flow profiles. The results show good agreement between experiment and simulation. The limitations of this approach will be discussed.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80228507","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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