{"title":"Ultrasound Phased Arrays for Hyperthermia: New Techniques Based on the Field Conjugation Method","authors":"M. Ibbini, E. Ebbini, S. Umemura, C. Cain","doi":"10.1109/ULTSYM.1987.199081","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199081","url":null,"abstract":"Phased arrays, which can be focused and steered electronicaliy, offer an attractive alternative to the mechanically scanned focused systems currently in use. This could be attributed to the speed and flexibility o f electronic control systems which, while complex, can be implemented remotely from the a pplicator aperture. However, both electrical and mechanical scanning require a very intense focal spot which could increase the risk of unwanted nonthermal effects, e.g., cavitation. Moreover, hot spots proximal to the tumor might occur because of near-field beam overlapping due to scanning. In this paper, a method is proposed to allow scanning at reduced spatial-peak temporal-peak (SPTP) intensity compared to approaches used in conventional scanning techniques. Moreover, the method permits the direct synthesis of the more diffuse heating patterns useful in hyperthermia without the need for mechanical or electrical scanning.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130633571","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":"Measurement of Surface Acoustic Wave Velocity Anisotropy with a Scanning Laser Acoustic Microscope","authors":"W. Robbins, E. Rudd","doi":"10.1109/ULTSYM.1987.199066","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199066","url":null,"abstract":"The measurement of the velocity and power flow angle of surface acoustic waves (SAWS) using a scanning laser acoustic microscope is described. Data obtained from a single scan by the microscope and from a single direction of insonification is Fourier transformed from the spatial domain into the spatial frequency domain. The incident cw surface waves scatter from the s ides of the sample into all possible wavevectors. Thus, the Fourier transform in the spatial frequency domain is the inverse velocity or slowness curve for surface waves propagaging on the material. From this curve, the phase velocity, group velocity, and power flow angle versus propagation direction can be obtained. Experimental results for YZ lithium niobate, ST quartz, and (111) silicon are in good agreement w i t h the o ret i ca 1 c a1 cu 1 at i on s.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"418 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122980276","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":"Design and Performance of Oscillators Using Semiconductor Delay Lines","authors":"S. Burns, G. R. Kline, K. Lakin","doi":"10.1109/ULTSYM.1987.198985","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.198985","url":null,"abstract":"Bulk-acoustic-wave piezoelectric thin-film technology has been used to synthesize delay lines at microwave frequencies in semiconductor substrates. These structures use either ZnO or AlN for piezoelectric transduction, suitably positioned electrodes for applying an ac signal, and reflecting surfaces for guiding the acoustic energy. the top-side of the semiconductor wafer. We can incorporate these delay structures as the feedback element in an oscillator and exploit the 2n periodicity in these structures to obtain a comb generator output. delay-line oscillators operating near 1 GHz and 3 MHz spectral line spacing. exceeds -90 dBc/Hz at 1 kHz. Design and analysis is based upon the use of SPICE 2G linear circuit models. Because the transducer fabrication process uses semiconductor processing technology as its basis, the synthesis of these oscillators is being studied as an integrable alternative to other technologies. The delay lines are accessed entirely","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128876685","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":"Ion Implantation Characterisation: A Comparison of Photothermal Radiometric and Photodisplacement Thermal Wave Techniques","authors":"G. Crean, S. Sheard, C. See, M. Somekh","doi":"10.1109/ULTSYM.1987.199027","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199027","url":null,"abstract":"In this work we evaluate the applicability of two nondestructive thermal wave techniques for ion implant monitoring, these being photodisplacement and photothermal radiometric microscopy. Experimental results are presented for BFz implants into single-crystal (100) silicon wafers with implantation parameters varied as follows: Ion dose (lE12-3E15 ions/cm* ) and ion energy (50-200 keV). Using these results, the sensitivity of the above techniques to material parameters such as lattice damage, ion penetration depth and surface recombination velocity is discussed. We will show that while no one technique is applicable to all implant characteristics, the various techniques examined are complementary and thus application specific.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"267 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116486635","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":"Laser-Induced Acoustic Shock Waves","authors":"B. Tittmann, L. Graham, R. Linebarger","doi":"10.1109/ULTSYM.1987.199130","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199130","url":null,"abstract":"The use of laser pulses to induce elastic waves in materials has many applications, ranging from weapons damage to noncontact NDE. This paper presents preliminary results on the generation of high-pressure nonlinear acoustic waves by the use of high-intensity laser pulses. The laser used was a Nd:YAC Q-switched laser with a wavelength of 1.06 microns, peak energy of 700 mj, peak power of - 108 W/cm2, Gaussian intensity profile and pulsewidth of 10 ns. In the first phase of the experiments, a water volume was chosen as a model propagation medium to simulate a homogeneous, isotropic medium supporting only longitudinal waves. The beam was focussed onto the water to achieve the intensity necessary to cause dielectric breakdown, evidenced by optical emissions. The resulting acoustic shock waves were detected with a commercial hydrophone PKI4 (2.54 mm diameter) with a frequency response flat to 300 kHz. This was used to measure the frequencydependent ultrasonic radiation pattern at a distance of 1 m as a function of elevation angle, laser intensity and depth of focal point below the surface of the water. Similar but somewhat sharper results were obtained when the focus was changed from near surface to 30 mm below the surface. The data substantiate that the effective source of the shock waves is in the shape of a small cylindrical column approximately 20 mm long in length, oriented perpendicular to the surface, and some distance below it, depending upon the focal point of the laser beam.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121562050","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":"Toolbit Mounted Thin Film Zinc Oxide Sensors for Process Control in Lathe and Milling Machine Applications","authors":"B. Bischoff, S. Ramalingam, W. Robbins","doi":"10.1109/ULTSYM.1987.199029","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199029","url":null,"abstract":"Thin films (1.8 microns thick) of ZnO have been deposited on tungsten carbide tool inserts by rf diode sputtering. The goal is to use ZnO film as a sensor to monitor acoustic emission generated during cutting or t ool fracture. The sensor has detected resonances in the machine structure in the 100 Hz to 20 KHz range as well as acoustic emission signals originating at the cutting site in the 100- 500 KHz range. During forced tool fracture, distinctive signals were observed from the sensor which could be used for cutting operation shut-down. The measured ZnO stress sensitivity averaged about 0.022 v-m/N which is about 35% of the s ingle crystal value. The highest observed was about 0.04 v-m/N. The sensor was still operational at the end of the useful cutting lifetime of the i nsert.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131854315","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":"Acoustical Nonlinear Parameter and Sound Speed Characteristics of Human Fat Tissues","authors":"R. Errabolu, C. Sehgal, R. Bahn, J. Greenleaf","doi":"10.1109/ULTSYM.1987.199110","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199110","url":null,"abstract":"Acoustical nonlinear parameter B/A (adiabatic), (B/A)’ (isothermal), sound speed c and density P measurements in the temperature range of 2OoC to 37OC have been made in excised fat tissues obtained from different parts of the human body. Magnitudes of temperature coefficients of sound speed and difference between adiabatic and isothermal values of B/A correlated highly with water content of the tissue. A reciprocal relationship between B/A and c was observed in soft tissues. In contrast, a linear relationship between B/A and c was observed in protein solutions. No correlation has been found either with B/A or with c with the age of the person from whom the fat tissues were obtained.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123122095","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":"Convergence and Speed of the Sinc Basis Moment Method","authors":"T. J. Cavicchi, W. O’Brien","doi":"10.1109/ULTSYM.1987.199091","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199091","url":null,"abstract":"A method for applying the fast Fourier t ransform to the convolutions arising in the internal field equations of the sinc basis moment method diffraction tomography algorithm is described. Exactly e quivalent results are obtained, whil redu ing the order of those computations from n f to n s log n for an nxn reconstruction. As originally derived, the sinc ba is moment method has an order of computation of ns for an nxn reconstruction. To reduce this order, spatial convolutions in the internal field equations were performed by a somewhat unusual application of the FFT. Specifically, if f $1 and f 41lnc represent, respectively, the total and incident ultrasonic fields evaluated at pixel 1 due to a transmitter at 1 ocati on $ , is the object function evaluated at pixel j, ',id Clj are coefficients resulting from the s inc basis expansions and integrations (Johnson and Tracy, 1983),","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114633607","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":"Development of a Divided Ring Array for Three-Dimensional Beam Steering in Ultrasonic Nondestructive Testing","authors":"H. Schwarz","doi":"10.1109/ULTSYM.1987.199080","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199080","url":null,"abstract":"This paper focuses on a newly developed device based on a 2 MHz divided-ring array for nondestructive testing (NDT) application with two rings, 48 elements, and an aperture of 30 mm. Using this array, it is possible to steer an ultrasound beam three-dimensionally in space within a range of * 45 degrees (longitudinal-wave excitation) and * 30-70 degrees (shear-wave excitation). Computations of the directivity pattern, the process of the theoretical optimization, experiments, and a defect reconstruction will be described. One example of a defect reconstruction has been performed representatively, illustrating that the image quality of the first prototype is improved when it is compared to linear array images because of the higher lateral resolution in elevation direction.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116762747","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":"Detection of Bondline Delaminations in Multilayer Structures with Lossy Components","authors":"E. Madaras, W. Winfree, B. T. Smith, J. Heyman","doi":"10.1109/ULTSYM.1987.199117","DOIUrl":"https://doi.org/10.1109/ULTSYM.1987.199117","url":null,"abstract":"The detection of bondline delaminations in multilayer structures using ultrasonic reflection techniques is a generic problem in adhesively bonded composite structures such as the Space Shuttles's Solid Rocket Motors (SRM). Standard pulse echo ultrasonic techniques do not perform well for a composite resonator composed of a resonant layer combined with attenuating layers. Excessive ringing in the resonant layer tends to mask internal echoes emanating from the attenuating layers. The SRM is made up of a resonant steel layer backed by layers of adhesive, rubber, liner and fuel, which are ultrasonically attenuating. The structure's response is modeled as a lossy ultrasonic transmission line. The model predicts that the acoustic response of the system is sensitive to delaminations at the interior bondlines in a few narrow frequency bands. These predictions are verified by measurements on a fabricated system. Successful imaging of internal delaminations is sensitive to proper selection of the interrogating frequency. Images of fabricated bondline delaminations are presented based on these studies.","PeriodicalId":309261,"journal":{"name":"IEEE 1987 Ultrasonics Symposium","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115611517","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}