The hybrid nature of optoacoustic imaging might impose limitations on concurrent placement of optical and ultrasonic detection components, especially in high resolution microscopic applications that require dense arrangements and miniaturization of components. This hinders optimal deployment of the optical excitation and ultrasonic detection paths, leading to reduction of imaging speed and spat...

The Laser ultrasonic technique (LUT) is an interesting method to perform inspection of large aeronautical panels of complex shapes. Its non-contact feature avoids coupling problems and could improve the efficiency of the NDT inspection in the composite manufacturing industry. If the ultrasound generation process is well understood in metallic samples, the application of the technique in composi...

Possible optical setups for measurement of the peak-to-peak value of an ultrasonic transducer are described in this work. The Michelson interferometer with the calibrated nanopositioner in reference path and laser Doppler vibrometer were used for the basic measurement of vibration displacement. Langevin type of ultrasonic transducer is used for the purposes of Electro-Ultrasonic Nonlinear Spect...

BACKGROUND/AIMS Quantitative and objective technique to assess radiation-induced tissue fibrosis is important for clinicians to estimate the efficiency of radiotherapeutic schemes. It has been widely reported that ultrasonic properties are sensitive to changes of acoustic scatterers in biological tissues. Therefore, measurement of ultrasonic properties may serve as a potential assessment techni...

Nonlinear properties of lead zirconate-titanate ~PZT! piezoceramics are investigated using ultrasonic second harmonic generation technique. When a sinusoidal ultrasonic wave of frequency v0 is sent into a nonlinear material, the second harmonic wave with frequency 2v0 is generated. Through measuring the absolute amplitude of the fundamental (v0) and of the second harmonic (2v0) waves, the ultra...

The backscattered rf signals from the lungs of fetal sheep during their last trimester of development were digitized and processed in an attempt to correlate ultrasonic parameters with measured functional parameters related to lung maturation. The broadband, post- TGC , rf signal of a commercial B-mode ultrasonic scanner was digitized at a sampling rate of 25 MHz. Sorting excluded data from reg...

The effect of bonding parameters on the reliability of thick Al wire bond is investigated. Samples were prepared with 25 different designs with 5 different bonding parameters such as time, ultrasonic power, beginforce, end-force and touch-down steps (pre-compression) with 5 levels. The bond signals of ultrasonic generator were collected during bonding in order to obtain prior quality informatio...

Microencapsulation techniques are widely applied in the field of pharmaceutical production to control drugs release in time and in physiological environments. Ultrasonic-assisted atomization is a new technique to produce microencapsulated systems by a mechanical approach. Interest in this technique is due to the advantages evidenceable (low level of mechanical stress in materials, reduced energ...

one of the great challenges in the processing of materials using equal channel angular pressing (ecap) is the high forming forces required to produce large shear deformation in the material. researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. recently, ultrasonic vibrations are successfully implemented into the ecap proce...

The subsurface defect in the wheel tread caused from Rolling Stock Fatigue (RCF) has become more danger in high speed railway. The conventional UT and phased array UT have deficiency to find the subsurface defect from the tread surface because of limitation of ultrasonic near field. In this paper, the subsurface defect is studied by simulation and experimental results with ultrasonic technique....