In this study, vibration cutting has been applied to machining of a novel material, NiTi based shape memory alloy (SMA), using a commercial ultrasonic piezoelectric transducer to vibrate an ISO insert CCMT geometry cutting tool. The effect of vibration in turning process was characterized by investigating the surface roughness of workpiece and surface quality assessment of machined surface usin...

The mouse cerebral cortex was imaged in situ by photoacoustic tomography (PAT). Instead of a flat ultrasonic transducer, a virtual point detector based on a high numerical aperture (NA), positively focused transducer was used. This virtual point detector has a wide omnidirectional acceptance angle, a high sensitivity, and a negligible aperture effect. In addition, the virtual point detector can...

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing seve...

A noninvasive method for determining patency of saphenous vein coronary bypass grafts has been developed in our laboratory. The system consists of a pulsed ultrasonic Doppler, a position-sensing arm for the Doppler transducer, a memory oscilloscope, an electrocardiogram, and strip-chart recorder. Patients are studied with the transducer in the suprasternal notch and intercostal spaces. Wherever...

Significant improvement in the performance of capacitive microfabricated ultrasonic transducers is reported and the modifications which enable the progress are described. Air-coupled through-transmission of glass and steel at 2.3 MHz is demonstrated for the first time. Furthermore, a 20 pm step on a silicon wafer is detected with both amplitude and phase signals at 3 MHz. The same process used ...

We present tomographic imaging of biological tissues by use of microwave-induced acoustic signal. It was demonstrated that the acoustic signal was proportional to the intensity of the incident microwave and was related to the absorption property of microwave in the medium. Pulsed microwave radiation was used to illuminate the samples. Absorbed microwave energy caused thermoelastic expansion tha...