نتایج جستجو برای: ultrasound waves
تعداد نتایج: 220368 فیلتر نتایج به سال:
Ultrasound imaging utilizes the interaction of sound waves with living tissue to produce an image of the tissue or, in Doppler-based modes, determine the velocity of a moving tissue, primarily blood. These dynamic, real time images can be analyzed to obtain quantitative structural and functional information from the target organ. This versatile, noninvasive diagnostic tool is widely used and ac...
The present work describes the results of research a complex substances obtained from sedimentary wine yeast by extraction with food extractants use ultrasound. filtrates alcoholic extracts and sediments isolated filtrate were investigated. It has been shown that hydrophobic moderately soluble poorly in alcohol, such as ethyl esters fatty acids, phospholipids, sterols, squalene, alcohol-contain...
Certain diseases produce changes in the elastic properties of soft tissues. Conventional imaging modalities in some cases have poor performance in diagnosing these types of diseases. To overcome this problem, elastographic imaging techniques that focus on evaluating the elastic properties of tissues, i.e., tissue stiffness, have been developed in the past three decades. Soft tissues, however, i...
The results of NDE and material characterization with mode conversion of air-coupled ultrasound into plate and surface waves in solids are reported. Singleand both-sided configurations of efficient slanted wave conversion are developed and tested for various materials. An alternative option is based on the excitation of cylindrical plate and surface waves by a focused air-coupled beam incident ...
The need for efficient extraction of plant constituents with a high yield and purity limitations to conventional techniques that are limited by mass transfer, has resulted in the development new processes. Sonochemistry involves cavitation induced pressure fluctuations generated ultrasound waves liquid medium. Ultrasound can be effectively used increase transfer rate solid-liquid present work e...
The discovery that ultrasound waves could be focused inside the skull and heated to high temperatures at a focal point goes back to 1944. However, because the skull causes the ultrasound waves to attenuate and scatter, it was believed that application of this technology would be difficult, and that it would be impossible to use this approach in the surgical treatment of intracranial diseases. E...
The significant morbidity and mortality associated with coronary artery disease has spurred the development of intravascular imaging devices to optimize the detection and assessment of coronary lesions and percutaneous coronary interventions. Intravascular ultrasound (IVUS) uses reflected ultrasound waves to quantitatively and qualitatively assess lesions; integrated backscatter and virtual his...
Amplitude-Modulation FrequencyModulation (AM-FM) decompositions represent images using spatially-varying sinusoidal waves and their spatially-varying amplitudes. The model uses different scales and bandpass filters to characterize the wide range of frequencies that may be present in an image. In the past few years, as the understanding of its theory advanced, AM-FM has been used in a series of ...
Background/introduction Transcranial MR-guided Focused Ultrasound (TcMRgFUS) treatments are now clinically performed on adult patients for brain tumor or essential tremor therapies. However, no application has been proposed for children despite their thinner skull being less of an acoustic barrier and the presence of a fontanelle on neonates, which could constitute a natural acoustic window for...
We have designed and built an apparatus for real-time acoustic imaging of convective flow patterns in optically opaque fluids. This apparatus takes advantage of recent advances in two-dimensional ultrasound transducer array technology; it employs a modified version of a commercially available ultrasound camera, similar to those employed in nondestructive testing of solids. Images of convection ...
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