PubMed · 3462195
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J A McNamara. 1986. Utility arches.. https://pubmed.ncbi.nlm.nih.gov/3462195/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Hybrid external fixators with limited internal fixation have become popular in the treatment of complex intraarticular fractures of the tibia. A wide variety of hybrid external fixation systems are commercially available, but these frames are expensive and not always readily available. The authors present a simple hybrid frame constructed from the AO tubular and Ilizarov type external fixator sets using a modified AO single adjustable clamp. This hybrid frame is easy to apply, versatile, and significantly less expensive than other commercially available adaptors and frames.
Explore the source record for details and available documents.
Medical B-mode scanners operating under conditions typically encountered during clinical work produce ultrasonic wave fields that undergo nonlinear distortion. In general, the resulting harmonic beams are narrower and have lower sidelobe levels than the fundamental beam, making them ideal for imaging purposes. This work demonstrates the feasibility of nonlinear harmonic imaging in medical scanners using a simple broadband imaging arrangement in water. The ultrasonic system comprises a 2.25-MHz circular transducer with a diameter of 38 mm, a membrane hydrophone, also with a diameter of 38 mm, and a polymer lens with a focal length of 262 mm. These components are arranged coaxially giving an imaging geometry similar to that used in many commercial B-scanners, but with a receiver bandwidth sufficient to record the first four harmonics. A series of continuous wave and pulse-echo measurements are performed on a wire phantom to give 1-D transverse pressure profiles and 2-D B-mode images, respectively. The reflected beamwidths wn decrease as wn/W1 = 1/n0.78, where n is the harmonic number, and the reflected sidelobe levels fall off quickly with increasing n. In imaging terms, these effects correspond to a large improvement in lateral resolution and signal-to-clutter ratio for the higher harmonics.