M. Fujiwara, M. Tanabe, N. Akazawa, K. Okubo, N. Tagawa
Tissue harmonic imaging can get fine images, and by adopting pulse compression technique to it, imaging with high signal-to-noise ratio can be realized besides. In order to achieve optimal pulse compression, it is important to prepare and use a suitable template waveform. However, since tissue harmonic component in echo signal has complicated characteristics, such the template is difficult to be completely known. In this study, we investigate the relationship between template waveforms used in harmonic pulse compression imaging and compressed waveforms experimentally.
{"title":"P3B-7 Study on Harmonic Pulse Compression Imaging with Consideration of Harmonic Property","authors":"M. Fujiwara, M. Tanabe, N. Akazawa, K. Okubo, N. Tagawa","doi":"10.1109/ULTSYM.2007.442","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.442","url":null,"abstract":"Tissue harmonic imaging can get fine images, and by adopting pulse compression technique to it, imaging with high signal-to-noise ratio can be realized besides. In order to achieve optimal pulse compression, it is important to prepare and use a suitable template waveform. However, since tissue harmonic component in echo signal has complicated characteristics, such the template is difficult to be completely known. In this study, we investigate the relationship between template waveforms used in harmonic pulse compression imaging and compressed waveforms experimentally.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"13 1","pages":"1756-1759"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78564750","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}
Shougang Wang, Wei-Ning Lee, Jianwen Luo, E. Konofagou
The frame-rate of ultrasound radio-frequency (RF) data acquisition is critical for imaging of the pulse wave and electromechanical wave propagation in cardiovascular tissues as well as improving the strain estimation. Therefore, an automated method had been developed to overcome the frame-rate limitations on standard systems by retrospective multi-sector signal acquisition through an electrocardiogram (ECG) gating technique. The method achieved a frame rate of 481 Hz at a 100% field of view, 64 line densities and an imaging depth of 11 cm. The composite full-view images were reconstructed by retrospectively combining seven small-sector RF frames using the ECG-gating technique. The axial displacements of both long-axis and short-axis views of a human left ventricle and a long-axis view of the abdominal aorta were calculated using an RF based speckle-tracking technique comprising ID cross-correlation methods in a 2D search (window size of 6.9 mm and overlap of 80%). Several sequences of electromechanical waves propagating in a left ventricular long-axis and short-axis view, and long-axis view of abdominal aorta were imaged at high frame rates. Currently, the method was implemented on an Ultrasonix RP system (Ultrasonix Medical Corp. Richmond, Canada) and could be potentially implemented on other clinical systems.
超声射频(RF)数据采集的帧率对于脉搏波成像和机电波在心血管组织中的传播以及改善应变估计至关重要。因此，开发了一种自动化的方法，通过心电图(ECG)门控技术，通过回顾性多扇区信号采集来克服标准系统的帧率限制。该方法在100%视场、64线密度和11 cm成像深度下实现了481 Hz的帧率。利用脑电图门控技术将7个小扇形射频帧进行回顾性组合，重建复合全视图图像。使用基于RF的散斑跟踪技术，包括二维搜索中的ID相互关联方法(窗口大小为6.9 mm，重叠度为80%)，计算了人左心室长轴和短轴视图以及腹主动脉长轴视图的轴向位移。在高帧率下对左心室长轴、短轴和腹主动脉长轴图像中传播的多个序列的机电波进行成像。目前，该方法已在ultrasix RP系统(ultrasix Medical Corp. Richmond, Canada)上实施，并有可能在其他临床系统上实施。
{"title":"10B-6 A Composite Imaging Technique for High Frame-Rate and Full-View Cardiovascular Ultrasound and Elasticity Imaging","authors":"Shougang Wang, Wei-Ning Lee, Jianwen Luo, E. Konofagou","doi":"10.1109/ULTSYM.2007.225","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.225","url":null,"abstract":"The frame-rate of ultrasound radio-frequency (RF) data acquisition is critical for imaging of the pulse wave and electromechanical wave propagation in cardiovascular tissues as well as improving the strain estimation. Therefore, an automated method had been developed to overcome the frame-rate limitations on standard systems by retrospective multi-sector signal acquisition through an electrocardiogram (ECG) gating technique. The method achieved a frame rate of 481 Hz at a 100% field of view, 64 line densities and an imaging depth of 11 cm. The composite full-view images were reconstructed by retrospectively combining seven small-sector RF frames using the ECG-gating technique. The axial displacements of both long-axis and short-axis views of a human left ventricle and a long-axis view of the abdominal aorta were calculated using an RF based speckle-tracking technique comprising ID cross-correlation methods in a 2D search (window size of 6.9 mm and overlap of 80%). Several sequences of electromechanical waves propagating in a left ventricular long-axis and short-axis view, and long-axis view of abdominal aorta were imaged at high frame rates. Currently, the method was implemented on an Ultrasonix RP system (Ultrasonix Medical Corp. Richmond, Canada) and could be potentially implemented on other clinical systems.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"3 1","pages":"880-883"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84167469","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}
A heat conductive array transducer was designed for transmitting high power ultrasound as well as transmitting and receiving wideband pulse waves. In phase-conversion ultrasonic molecular imaging, tissue-selective nano-droplets are converted to contrast microbubbles by a long duration ultrasonic pulse with a relatively high amplitude. When a conventional imaging array transducer was used, sensitivity of transducer decreased caused by some breakdown processes. In this study, we firstly examined the breakdown process based on experiments and numerical simulations. The experimental result was consistent with the simulation result assuming peeling of the adhesive between two PZT layers. A new transducer structure using a heat conducting acoustic isolation layer (AIL) on a metal heat sink block was conceived to inhibit this type of breakdown while maintaining the wide bandwidth for imaging with a high resolution. Heat generated in the PZT and adjacent layers can diffuse into a metal heat conductor through the AIL. Since the AIL reflects pulses, a possible unwanted response due to reflection at the opposite side of the metal block will be suppressed. The temperature rise and the ultrasonic pulse response of the transducer were calculated using PZFlex. The temperature rise in the transducer immediately after driving at 40 V for 25 s with 1% duty ratio was 37 degrees for the proposed structure, much lower than that for the conventional structure of 56 degrees. No serious unwanted response was observed for the proposed structure. These results show that the proposed structure will be useful for a high-power wideband phased array transducer.
{"title":"9F-2 Heat Conductive Array Transducer for Phase-Conversion Molecular Imaging","authors":"T. Azuma, S. Sonoda, K. Kawabata, S. Umemura","doi":"10.1109/ULTSYM.2007.214","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.214","url":null,"abstract":"A heat conductive array transducer was designed for transmitting high power ultrasound as well as transmitting and receiving wideband pulse waves. In phase-conversion ultrasonic molecular imaging, tissue-selective nano-droplets are converted to contrast microbubbles by a long duration ultrasonic pulse with a relatively high amplitude. When a conventional imaging array transducer was used, sensitivity of transducer decreased caused by some breakdown processes. In this study, we firstly examined the breakdown process based on experiments and numerical simulations. The experimental result was consistent with the simulation result assuming peeling of the adhesive between two PZT layers. A new transducer structure using a heat conducting acoustic isolation layer (AIL) on a metal heat sink block was conceived to inhibit this type of breakdown while maintaining the wide bandwidth for imaging with a high resolution. Heat generated in the PZT and adjacent layers can diffuse into a metal heat conductor through the AIL. Since the AIL reflects pulses, a possible unwanted response due to reflection at the opposite side of the metal block will be suppressed. The temperature rise and the ultrasonic pulse response of the transducer were calculated using PZFlex. The temperature rise in the transducer immediately after driving at 40 V for 25 s with 1% duty ratio was 37 degrees for the proposed structure, much lower than that for the conventional structure of 56 degrees. No serious unwanted response was observed for the proposed structure. These results show that the proposed structure will be useful for a high-power wideband phased array transducer.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"11 1","pages":"836-839"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78254124","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}
In this paper we consider the problem of calculating the propagation of acoustic waves within an ideal solid isotropic multilayer plate structure. In such a situation the process of mode conversion as the wave interacts with each interface of the plate creates an ever increasing number of waves to track, and to perform calculations on, as the wave propagates within the layered media. We choose to explore this problem by examining the ray paths of the multiple reflections within the plate structure, and show that upon careful consideration many of these paths will travel equivalent distances in time and space becoming coincident. The principle of superposition can then be used to combine these coincident paths, this reduces the number of waves to track, and simplifies the problem so that the necessary calculations can be performed in a time efficient manner.
{"title":"P0-10 A Ray Technique to Calculate Multiple Reflected and Transmitted Waves in Layered Media","authors":"J. Sadler, R. Maev","doi":"10.1109/ULTSYM.2007.307","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.307","url":null,"abstract":"In this paper we consider the problem of calculating the propagation of acoustic waves within an ideal solid isotropic multilayer plate structure. In such a situation the process of mode conversion as the wave interacts with each interface of the plate creates an ever increasing number of waves to track, and to perform calculations on, as the wave propagates within the layered media. We choose to explore this problem by examining the ray paths of the multiple reflections within the plate structure, and show that upon careful consideration many of these paths will travel equivalent distances in time and space becoming coincident. The principle of superposition can then be used to combine these coincident paths, this reduces the number of waves to track, and simplifies the problem so that the necessary calculations can be performed in a time efficient manner.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"9 1","pages":"1221-1224"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73291349","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}
A method to greatly simplify the high-frame-rate (HFR) imaging system using a rotation of coordinates in image reconstruction was developed. A theory of Fourier image reconstruction was also developed and both in vitro (on an ATS539 tissue-mimicking phantom) and in vivo (on a human heart) experiments were performed to verify the theory.
{"title":"2C-5 Simplification of High Frame Rate Imaging System with Coordinate Rotation","authors":"Jian-yu Lu, S. Kwon","doi":"10.1109/ULTSYM.2007.22","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.22","url":null,"abstract":"A method to greatly simplify the high-frame-rate (HFR) imaging system using a rotation of coordinates in image reconstruction was developed. A theory of Fourier image reconstruction was also developed and both in vitro (on an ATS539 tissue-mimicking phantom) and in vivo (on a human heart) experiments were performed to verify the theory.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"27 1","pages":"33-36"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73316730","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}
Discovered by Lagasse in early 1970's through a numerical study, wedge waves are guided acoustic waves propagating along the tip of a wedge, with energy tightly confined near the apex. Like Lamb waves, wedge waves with displacement field anti-symmetric about the mid-apex-plane are called anti-symmetric flexural (ASF) modes. Without apex truncation, the ASF modes are non-dispersive. However, with apex truncation, the ASF modes are dispersive and the dispersion relation is highly sensitive to the apex truncation. In this research, a laser ultrasound technique (LUT) with a three- dimensional scanning is employed for a non-contact measurement of the ASF dispersion which is related to the tool wear. The basic measurement principle is the dispersion behavior of ASF mode influenced by the wear condition of the machine tool. Figure 1 shows a micrograph of the tool tip before it is used for machining. The tool is then arranged for a sequence of machining/LUT measurement procedure. The ASF dispersion curve is strongly influenced by the machining time. The measured dispersion slopes show as good measure for the quantitative wear of the tools. The current result suggests that dispersion of the ASF modes propagating along the tool tip could be an effective measure for the wear condition. The current technique is continuously been developed to meet the criteria of serving as an on-line wear characterizing technique.
{"title":"P4G-6 A New Method for the Inspection of Tool Wear Based on the Dispersion of ASF Modes","authors":"Che-Hua Yang, Chia-hao Hsu, S. Du","doi":"10.1109/ULTSYM.2007.518","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.518","url":null,"abstract":"Discovered by Lagasse in early 1970's through a numerical study, wedge waves are guided acoustic waves propagating along the tip of a wedge, with energy tightly confined near the apex. Like Lamb waves, wedge waves with displacement field anti-symmetric about the mid-apex-plane are called anti-symmetric flexural (ASF) modes. Without apex truncation, the ASF modes are non-dispersive. However, with apex truncation, the ASF modes are dispersive and the dispersion relation is highly sensitive to the apex truncation. In this research, a laser ultrasound technique (LUT) with a three- dimensional scanning is employed for a non-contact measurement of the ASF dispersion which is related to the tool wear. The basic measurement principle is the dispersion behavior of ASF mode influenced by the wear condition of the machine tool. Figure 1 shows a micrograph of the tool tip before it is used for machining. The tool is then arranged for a sequence of machining/LUT measurement procedure. The ASF dispersion curve is strongly influenced by the machining time. The measured dispersion slopes show as good measure for the quantitative wear of the tools. The current result suggests that dispersion of the ASF modes propagating along the tool tip could be an effective measure for the wear condition. The current technique is continuously been developed to meet the criteria of serving as an on-line wear characterizing technique.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"25 1","pages":"2061-2063"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76656889","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}
This work reports on the implementation of VHF MEMS bandpass filters by capacitive coupling of Silicon Bulk Acoustic wave Resonators (SiBAR) fabricated using the HARPSS-on-SOI fabrication process. Such resonators operate in their horizontal width extensional modes with quality factors (Q) in the range of 10,000-100,000. With the comparatively large electrode area and deep submicron capacitive transduction gaps these resonators have also exhibited relatively low impedances. Compared with existing technologies such as quartz crystals, SAW filters, capacitively-coupled SiBARs have demonstrated the smallest form factor high-Q filters in the VHF range that can be integrated with silicon electronics on a common substrate. Filters with center frequencies up to 150MHz are demonstrated by coupling of two SiBAR resonators in their fundamental width- extensional modes. Tuning of the filter bandwidth by varying the DC polarization voltages on the resonators is investigated.
{"title":"P2G-2 Capacitively Coupled VHF Silicon Bulk Acoustic Wave Filters","authors":"Qishu Qin, S. Pourkamali, F. Ayazi","doi":"10.1109/ULTSYM.2007.415","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.415","url":null,"abstract":"This work reports on the implementation of VHF MEMS bandpass filters by capacitive coupling of Silicon Bulk Acoustic wave Resonators (SiBAR) fabricated using the HARPSS-on-SOI fabrication process. Such resonators operate in their horizontal width extensional modes with quality factors (Q) in the range of 10,000-100,000. With the comparatively large electrode area and deep submicron capacitive transduction gaps these resonators have also exhibited relatively low impedances. Compared with existing technologies such as quartz crystals, SAW filters, capacitively-coupled SiBARs have demonstrated the smallest form factor high-Q filters in the VHF range that can be integrated with silicon electronics on a common substrate. Filters with center frequencies up to 150MHz are demonstrated by coupling of two SiBAR resonators in their fundamental width- extensional modes. Tuning of the filter bandwidth by varying the DC polarization voltages on the resonators is investigated.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"75 1","pages":"1649-1652"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77066349","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}
Mechanical in vitro tests and in vivo elasticity imaging have shown differences between breast tissue types in their nonlinear stress/strain behavior, which could be utilized to differentiate between benign and malignant lesions potentially reducing the benign biopsy rate. Stress and strain measurements are required for absolute measures of this non-linear behavior in vivo. A variety of tests were performed with a prototype pressure sensor array to gauge its stability, sensitivity and calibration in reference to its application in ultrasound elastography. Measurements on elastographic phantoms were also performed and compared to finite element analysis (FEA) simulations. In addition, data was collected from patients undergoing ultrasound elasticity imaging at the University of Wisconsin Breast Center. Initial tests show that the pressure sensor array is stable in an ultrasound imaging environment. A reliable calibration technique was also developed, with reproducibility to within 5% for most elements. Tests also show a wide disparity in sensitivity among elements. The best performing elements are capable of detecting pressure as low as about 100 Pa. The average minimum detectable pressure was about 800 Pa. This suggests that the array is capable of detecting initial contact and measuring the contact force during a deformation of the breast - a critical task for quantifying stress/strain nonlinearities. The preliminary clinical trial confirmed this prediction. However, surface pressure distribution measurements on phantoms have shown only modest agreement with FEA simulations. Geometric uncertainties on the surface of the sensor as well as the variability of the absolute calibration make the array ill suited to measure accurate maps of the surface pressure distribution which might limit its utility for elastic modulus reconstructions.
{"title":"P4F-7 Integration of a Pressure Sensing Array Into Ultrasound Elastography","authors":"L. Kiessel, T. Hall, Jingfeng Jiang","doi":"10.1109/ULTSYM.2007.514","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.514","url":null,"abstract":"Mechanical in vitro tests and in vivo elasticity imaging have shown differences between breast tissue types in their nonlinear stress/strain behavior, which could be utilized to differentiate between benign and malignant lesions potentially reducing the benign biopsy rate. Stress and strain measurements are required for absolute measures of this non-linear behavior in vivo. A variety of tests were performed with a prototype pressure sensor array to gauge its stability, sensitivity and calibration in reference to its application in ultrasound elastography. Measurements on elastographic phantoms were also performed and compared to finite element analysis (FEA) simulations. In addition, data was collected from patients undergoing ultrasound elasticity imaging at the University of Wisconsin Breast Center. Initial tests show that the pressure sensor array is stable in an ultrasound imaging environment. A reliable calibration technique was also developed, with reproducibility to within 5% for most elements. Tests also show a wide disparity in sensitivity among elements. The best performing elements are capable of detecting pressure as low as about 100 Pa. The average minimum detectable pressure was about 800 Pa. This suggests that the array is capable of detecting initial contact and measuring the contact force during a deformation of the breast - a critical task for quantifying stress/strain nonlinearities. The preliminary clinical trial confirmed this prediction. However, surface pressure distribution measurements on phantoms have shown only modest agreement with FEA simulations. Geometric uncertainties on the surface of the sensor as well as the variability of the absolute calibration make the array ill suited to measure accurate maps of the surface pressure distribution which might limit its utility for elastic modulus reconstructions.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"13 1","pages":"2046-2049"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82414945","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}
In this paper, we present our recent study on the fabrication and characterization of the ZnO nanowires gas sensor using thickness shear mode (TSM) langasite resonators. C-axis vertically aligned ZnO nanowire arrays were synthesized on the langasite resonator by using an utrathin ZnO seed layer through a simple hydrothermal route. The nanowires were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). N02 as the target gas was particularly used to investigate the sensing performance of langasite resonator sensors with nanostructured ZnO interfacial layer at high temperature conditions. The results indicated the use of the ZnO nanowire arrays on acoustic wave resonator can greatly enhance the sensitivity and sensor response speed due to the fast surface/interface reaction and surface roughness.
{"title":"P1D-2 High Temperature Langasite BAW Gas Sensor Based on ZnO Nanowire Arrays","authors":"Hongbin Cheng, Lifeng Qin, Qing-Ming Wang","doi":"10.1109/ULTSYM.2007.342","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.342","url":null,"abstract":"In this paper, we present our recent study on the fabrication and characterization of the ZnO nanowires gas sensor using thickness shear mode (TSM) langasite resonators. C-axis vertically aligned ZnO nanowire arrays were synthesized on the langasite resonator by using an utrathin ZnO seed layer through a simple hydrothermal route. The nanowires were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). N02 as the target gas was particularly used to investigate the sensing performance of langasite resonator sensors with nanostructured ZnO interfacial layer at high temperature conditions. The results indicated the use of the ZnO nanowire arrays on acoustic wave resonator can greatly enhance the sensitivity and sensor response speed due to the fast surface/interface reaction and surface roughness.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"25 1","pages":"1361-1364"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82251553","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}
A. Tweedie, R. O’Leary, G. Harvey, A. Gachagan, C. Holmes, P. Wilcox, B. Drinkwater
This paper describes the use of a 550 (25times22) element 2 MHz 2D piezoelectric composite array in immersion mode to image an aluminum test block containing a collection of artificial defects. The defects included a 1 mm diameter side-drilled hole, a collection of 1 mm slot defects with varying degrees of skew to the normal and a flat bottomed hole. The data collection was carried out using the full matrix capture; a scanning procedure was developed to allow the operation of the large element count array through a conventional 64-channel phased array controller. A 3D TFM algorithm capable of imaging in a dual media environment was implemented in MATLAB for the offline processing the raw scan data. This algorithm facilitates the creation of 3D images of defects while accounting for refraction effects at material boundaries. In each of the test samples interrogated the defects, and their spatial position, are readily identified using TFM. Defect directional information has been characterized using VTFM for defect exhibiting angles up to and including 45deg of skew.
{"title":"11D-2 Total Focussing Method for Volumetric Imaging in Immersion Non Destructive Evaluation","authors":"A. Tweedie, R. O’Leary, G. Harvey, A. Gachagan, C. Holmes, P. Wilcox, B. Drinkwater","doi":"10.1109/ULTSYM.2007.259","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.259","url":null,"abstract":"This paper describes the use of a 550 (25times22) element 2 MHz 2D piezoelectric composite array in immersion mode to image an aluminum test block containing a collection of artificial defects. The defects included a 1 mm diameter side-drilled hole, a collection of 1 mm slot defects with varying degrees of skew to the normal and a flat bottomed hole. The data collection was carried out using the full matrix capture; a scanning procedure was developed to allow the operation of the large element count array through a conventional 64-channel phased array controller. A 3D TFM algorithm capable of imaging in a dual media environment was implemented in MATLAB for the offline processing the raw scan data. This algorithm facilitates the creation of 3D images of defects while accounting for refraction effects at material boundaries. In each of the test samples interrogated the defects, and their spatial position, are readily identified using TFM. Defect directional information has been characterized using VTFM for defect exhibiting angles up to and including 45deg of skew.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"7 1","pages":"1017-1020"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87628988","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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