2002 IEEE Ultrasonics Symposium, 2002. Proceedings.最新文献_第7页

Microsphere capture and perfusion in microchannels using flexural plate wave structures 利用弯曲板波结构在微通道中捕获和灌注微球

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193445

J. Black, R. White, J. Grate

引用次数: 11

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1192671

F. Viola, W. Walker

{"title":"Shear strain elastography","authors":"F. Viola, W. Walker","doi":"10.1109/ULTSYM.2002.1192671","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192671","url":null,"abstract":"In the breast, prostate and other organs increased tissue stiffness is often associated with the presence of disease. While palpation remains widely used, it has limited sensitivity which is highly dependent upon the skill of the clinician. To overcome this and other limitations a variety of automated approaches have been developed in recent years. These techniques generate tissue deformation by applying acoustic radiation force internally, shear waves superficially, or axial compression. In this paper we propose an alternate approach for elasticity imaging. A shear deformation is applied to the tissue surface. Ultrasound images obtained before and after shear application are processed to yield images of shear strain. We tested this method experimentally on custom acrylamide gel phantoms using a Philips SONOS 5500 imaging system. The phantoms consisted of a 5% acrylamide background with 15% acrylamide inclusions. 50 /spl mu/m sephadex spheres were used in the background and inclusion to introduce ultrasonic scattering. 4% shear rates were generated by translating the upper surface of the 5 cm thick phantoms by 2.0 mm. The shear strains observed within the inclusions of each phantom were roughly one third those seen in the background region. As anticipated, little axial deformation was observed. Experimentally obtained shear strain images clearly delineate the inclusions with few artifacts, although some noise is visible. This noise undoubtedly arises from jitter in the lateral displacement estimates. Theoretical analysis suggests that signal decorrelation under lateral shear will be very small. This, coupled with the minimal artifacts visible in the shear strain images may make shear elastography an attractive alternative to techniques.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125840108","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}

引用次数: 7

Stepping motion analysis of surface acoustic wave motor toward nanometer resolution positioning system 面向纳米分辨率定位系统的表面声波电机步进运动分析

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193487

T. Shigematsu, M.K. Kuroswa, K. Asai

引用次数: 5

Three-dimensional real-time synthetic aperture imaging using a rotating phased array transducer 利用旋转相控阵换能器进行三维实时合成孔径成像

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1192596

S. Nikolov, J. A. Jensen, R. Dufait, Armin Schoisswohl

{"title":"Three-dimensional real-time synthetic aperture imaging using a rotating phased array transducer","authors":"S. Nikolov, J. A. Jensen, R. Dufait, Armin Schoisswohl","doi":"10.1109/ULTSYM.2002.1192596","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192596","url":null,"abstract":"Current 3D real-time imaging is done either with sparse 2D arrays, or with mechanically moved phased arrays. The former results in a poor resolution and contrast due to a limited amount of elements. The latter has the disadvantage of low frame rates due to the sequential acquisition of the volume line-by-line and plane-by-plane. This paper describes an approach which combines mechanically moved phased array with synthetic transmit aperture imaging, resulting in high volume acquisition rates without a trade-off in image quality. The scan method uses a conventional fully populated 64 element phased array, which is rotated over the volume of interest. The data is acquired using coded signals and synthetic transmit aperture imaging. Only one group of elements transmits at a time. The delays are set such as to form a cylindrical wave. The back-scattered signal carries information not only from the plane located directly below the transducer, but also from neighboring planes. A complete dataset for all elements for the whole rotation is acquired and stored. The volume is then focused from this complete data set in order to obtain dynamic transmit and receive focusing in all directions.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125014000","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}

引用次数: 24

A mechanical vibration sensing technique using a liquid delay line oscillator 一种利用液体延迟线振荡器的机械振动传感技术

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193541

T. Fujita, K. Toda

引用次数: 0

Finite element simulation of bulk- and surface acoustic wave (SAW) interaction in SAW devices 声表面波与体声相互作用的有限元模拟

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193351

M. Hofer, N. Finger, G. Kovacs, J. Schoberl, U. Langer, R. Lerch

引用次数: 28

Tuning fork QCM. Application to powder and gel technology 音叉QCM。应用于粉末和凝胶技术

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193447

L. Matsiev

引用次数: 1

Mass flowmeters for fluids with density gradient 用于密度梯度流体的质量流量计

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193443

M. Rychagov, S. Tereshchenko, Y. Masloboev, M. Simon, L. Lynnworth

{"title":"Mass flowmeters for fluids with density gradient","authors":"M. Rychagov, S. Tereshchenko, Y. Masloboev, M. Simon, L. Lynnworth","doi":"10.1109/ULTSYM.2002.1193443","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193443","url":null,"abstract":"Quadrature integration of flow velocity along prescribed parallel paths has been one of the preferred solutions for accurate computation of volumetric flowrate Q for over thirty years. The present work extends the quadrature volumetric flowmetering method to determining from sound speed c/sub 3/ along the same quadrature paths, the fluid temperature T, density /spl rho/ and mass flowrate M/sub F/ in the presence of a density gradient. Quadrature integration of /spl rho//sub i/ /spl times/ V/sub i/ products V/sub i/ obtained from c/sub 3i/ is useful to the extent the fluid is sufficiently pure and defined so that the uncertainty in sound speed c/sub i/ along each path generates only a small uncertainty in density pi along those same paths. Instead of \"useful to the extent\" one could just as well say \"limited to the extent.\" Recognizing this limitation, it is interesting to compare the density and mass flowrate determined from (a) ultrasonic measurements of propagation across the fluid, as indicated above, with density and mass flowrate determinations based on two other known methods. These two methods are: (b) reflection coefficient measurement of fluid characteristic impedance Z, which would seem capable of leading to /spl rho/ after dividing by c; and determining /spl rho/ based on (c) torsional wavespeed in a waveguide of noncircular cross section.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127356276","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}

引用次数: 2

Acoustic waves in pressurized boreholes in formations with triaxial stresses 三轴应力地层中受压钻孔中的声波

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193453

B. Sinha, Qingchen Liu

{"title":"Acoustic waves in pressurized boreholes in formations with triaxial stresses","authors":"B. Sinha, Qingchen Liu","doi":"10.1109/ULTSYM.2002.1193453","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193453","url":null,"abstract":"A finite-difference formulation of equations of motion for elastic waves in prestressed formations has been used to calculate synthetic waveforms at an array of receivers in a liquid-filled borehole. Equations of motion for elastic waves in prestressed materials are derived from rotationally invariant equations of nonlinear elasticity. These equations describe the influence of borehole hydrostatic (mud) pressure as well as formation stresses on acoustic waves produced by either a monopole or dipole transmitter placed on the borehole axis. The synthetic waveforms are processed by a modified matrix pencil algorithm for isolating both dispersive and non-dispersive arrivals in the wavetrain. Computational results show that a difference in the maximum and minimum horizontal stresses causes dipole dispersion crossovers that can be used as an indicator of stress-induced anisotropy dominating the data. On the other hand, an increase in the overburden stress causes both the Stoneley and dipole dispersions to shift toward higher velocities by varying amounts at various frequencies. Any increase in the mud pressure introduces an altered annulus surrounding the borehole surface. This annulus exhibits radial variations in the near-wellbore radial and hoop stresses. Both the Stoneley and dipole dispersions show increasing velocities at higher frequencies. Changes in borehole acoustic wave velocities caused by a change in any one of the formation principal stresses yield frequency-dependent overburden, maximum horizontal, and minimum horizontal stress coefficients of velocities. These stress coefficients of velocities can be used to invert measured changes in borehole dispersions at various depths for corresponding changes in formation stresses.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127499088","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}

引用次数: 2

Echo signals processing with neural network in bat-like sonars based on PVDF 基于PVDF的类蝙蝠声纳回波信号神经网络处理

2002 IEEE Ultrasonics Symposium, 2002. Proceedings. Pub Date : 2002-10-08 DOI: 10.1109/ULTSYM.2002.1193515

A. Fiorillo, G. D'Angelo

引用次数: 7