In continuous wave ultrasonic Doppler tomography (DT), the ultrasonic beam moves relative to the scanned object to acquire Doppler-shifted frequency spectra which correspond to cross-range projections of the scattering and reflecting structures within the object. The relative motion can be circular or linear. These data are then backprojected to reconstruct the two-dimensional image of the obje...

ABSTRACT Acoustic streaming in a multi-well microplate is investigated using two different ultrasonic actuation frequency-schemes: Single-frequency and frequency-modulation. The streaming is tracked by the use of 1 μm fluorescent polymer beads and microparticle image velocimetry. The suspension also contained human B cells for studying the acoustic trapping and aggregation performance simultane...

Huia cavitympanum, an endemic Bornean frog, is the first amphibian species known to emit exclusively ultrasonic (i.e., >20 kHz) vocal signals. To test the hypothesis that these frogs use purely ultrasonic vocalizations for intraspecific communication, we performed playback experiments with male frogs in their natural calling sites. We found that the frogs respond with increased calling to broad...

In this paper, a new non-contact ultrasonic abrasive finishing mechanism is designed and fabricated. This mechanism combines the function of ultrasonic vibrations and the magnetic abrasive finishing (MAF) process. A permanent magnet which is mounted on a horn has been used as the processing tool. This polishing tool is vibrated at an ultrasonic frequency with piezo-electric actuators. Ultrasoni...

This paper describes ultrasonic image registration for multi-frequency analysis. The goal of our research is the portable and real time brain diagnosis under the thick-skull. The choice of ultrasonic frequency is a trade-off between spatial image resolution and imaging depth. This study shows the usability of data synthesis by employing two different frequency ultrasounds. In the first part of ...

In ultrasonic metal welding, two metal sheets are joined by the application of high frequency ultrasonic vibrations (20 kHz) under moderate pressure in which the vibrations are applied parallel to the interface between the sheets. The high frequency relative motion between the sheets forms a solid–state weld through progressive shearing and plastic deformation between surface asperities that di...

Because of the serious non-linearity and coupling among state variables caused by the complex energy conversion process in ultrasonic motor, the motion control strategy of ultrasonic motor still need to be studied in detail to obtain better performance. As a kind of special control method, the low-frequency PWM control strategy can make the on-line optimum control easier, and may be an effectiv...

Using numerical simulations, we investigated the responses of the π-phase-shifted fiber Bragg gratings (πFBGs) impinged by pressure ultrasonic waves. The effect of the grating length, grating refractive index modification depth, and ultrasonic frequency on the wavelength sensitivity and intensity sensitivity of the πFBG ultrasonic sensor for ultrasonic waves of different wavelengths was analyze...

Impregnating wood, assisted with ultrasound technology, could improve the impregnation efficiency by improving the permeability of wood, thus affecting the subsequent drying process. Poplar lumber and phenolic resin were applied to investigate the influence of ultrasound-assisted impregnation on the wood drying process. The ultrasonic frequency and processing time were analyzed and correlated. ...

A method is described for comparing the sensitivity of two hydrophones over the frequency range 1-15 MHz. This technique forms the basis for the dissemination of national ultrasonic standards in the U.K. over this frequency range. A reference hydrophone is placed in an ultrasonic field and then the device being calibrated is substituted and the two output voltages are compared. This substitutio...