This paper constitutes a progress rersort on the develol•ment of an ultrasonic instrument for detecting microstructure. The principle of operation of the device (designated by the term "ultrasonic microscope") is as follows: The specimen is imbedded in a liquid, which closely matches it in acoustic impedance, and is irradiated with sho•t pulses of highdreqnency hound. Some of the ultrasonic ene...

The transducer-lens system is one major component in the performance of an acoustic microscope. The design criteria for the various types of applications of an acoustic microscope are different. For surface imaging applications, it is desired to have a small spot size and low sidelobe level. For materials characterization and subsurface imaging applications (sue~ as subsurface crack imaging), i...

Event-related potentials (ERPs), accuracy scores, and reaction times were used to examine the recognition of emotional expressions. Adults and 7-year-old children saw upright and inverted chromatic slides of the facial expressions of happiness, fear, surprise, and anger, and were asked to press a button for either "happy" or "angry" faces. A positive-going waveform (P300) was apparent at pariet...

This paper presents a review of some of the research projects at University College London which use ultrasonic waves in non-destructive testing. The projects covered include a low-frequency scanning acoustic microscope, a new dark-field acoustic microscope, an update on finite difference model studies of wave propagation and scattering, developments,in mode-conversion techniques for defect cha...

Introduction Intraoperative electrocochleography (ECochG) during cochlear implantation is a promising tool to preserve residual hearing. However, the time gap between insertion of electrode and acoustic feedback from audiologist surgeon causes delay. For first real-time visualization intraoperative ECochG via digital microscope (ARRISCOPE​) directly using “picture-in-picture mode” was successfu...

Optoacoustic (OA) microscopy using an all-optical system based on the probe beam deflection technique (PBDT) for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i) efficient coupling of laser excitation energy to the samples being imaged through the probing...

An actuation method for atomic force microscope ~AFM! cantilevers in fluids is reported. The radiation pressure generated by a focused acoustic transducer at radio frequency ~rf! ~100–300 MHz! exerts a localized force of controlled amplitude at a desired location on the AFM cantilever. This force can be used to measure the spring constant and other dynamic properties of the cantilever. Furtherm...