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Title: Acoustic transducer for acoustic microscopy

Abstract

A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.

Inventors:
;
Publication Date:
OSTI Identifier:
7266217
Patent Number(s):
US 4909082; A
Application Number:
PPN: US 7-281941
Assignee:
Leland Stanford Junior Univ., CA (United States) PTO; EDB-94-118378
DOE Contract Number:
FG03-84ER45157
Resource Type:
Patent
Resource Relation:
Patent File Date: 6 Dec 1988
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; ACOUSTIC MICROSCOPY; LENSES; DESIGN; MICROSCOPES; TRANSDUCERS; POLARIZATION; MICROSCOPY; 440800* - Miscellaneous Instrumentation- (1990-)

Citation Formats

Khuri-Yakub, B.T., and Chou, C.H. Acoustic transducer for acoustic microscopy. United States: N. p., 1990. Web.
Khuri-Yakub, B.T., & Chou, C.H. Acoustic transducer for acoustic microscopy. United States.
Khuri-Yakub, B.T., and Chou, C.H. 1990. "Acoustic transducer for acoustic microscopy". United States. doi:.
@article{osti_7266217,
title = {Acoustic transducer for acoustic microscopy},
author = {Khuri-Yakub, B.T. and Chou, C.H.},
abstractNote = {A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1990,
month = 3
}
  • A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.
  • This patent describes a borehole seismic impulse source transducer comprising: an elastic outer housing and an elastic, electrically insulating inner housing each attached to and extending from a downhole end member to an uphole end member; hydraulic fluid filling space between the inner and the outer housing; an enclosed chamber formed in the inner housing, the chamber divided into an upper volume and a lower volume by an insulator having a small aperture channel therein, whereby the upper and lower volume of the chamber are in fluid communication, the chamber completely filled with electrolyte fluid; a first and second electrodemore » extending into the upper volume and the lower volume, respectively, and in spaced relation from one another; means for supplying high voltage across the electrodes whereby an arc discharge is produced through and in the vicinity of the aperture channel; means for intermittent venting of a gas build up produced as a result of a number of the arc discharges in the electrolyte fluid, the gas venting means having a means for sensing the gas build up with the chamber; and means for increasing pressure and volume of the hydraulic fluid for expanding the outer housing prior to the arc discharge and after the source transducer is positioned within a borehole.« less
  • An acoustic transducer is described comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2,000 psi of compressive stress. The transducer also includes a power supply and meansmore » to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers. 4 figs.« less
  • This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. Themore » motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control. 7 figs.« less