نتایج جستجو برای: ultrasonic absorption
تعداد نتایج: 159829 فیلتر نتایج به سال:
OBJECTIVE To present the frequency resonance hypothesis, a possible mechanical mechanism by which treatment with non-thermal levels of ultrasound stimulates therapeutic effects. The review encompasses a 4-decade history but focuses on recent reports describing the effects of nonthermal therapeutic levels of ultrasound at the cellular and molecular levels. DATA SOURCES A search of MEDLINE from...
ultrasonic machining (usm) is a mechanical material removal process used to erode holes and cavities in hard or brittle work pieces by using shaped tools, high-frequency and an abrasive slurry. this paper addresses the concept and development of an expert system (es) for hard and brittle material, such as glass, quartz, diamond, carbides, semi conducting materials, ceramic and graphite which ca...
High compressive strength concrete is desirable in the construction industry. The valuable effect of high-power ultrasonic manufacturing industries motivation this research For purpose, ultrasound was employed to increase concrete. Also, these waves on water absorption has been studied. Ultrasonic were tested two modes, one independently and other combination with conventional compaction method...
This thesis focuses on the possibility of using ultrasonic measurement techniques for energy gas characterization. The idea is to combine both on-line flow measurements with non-invasive fluid characterization in the same measurement setup using the same sensor(s). The long-term goal of the project is to develop measurement methods based on ultrasonic techniques that can measure; the flow rate,...
We have carried out boundary-layer-resolved, unstructured fully-compressible Navier– Stokes simulations of an ultrasonic standing-wave thermoacoustic engine (TAE) model. The model is constructed as a quarter-wavelength engine, approximately 4 mm by 4 mm in size and operating at 25 kHz, and comprises a thermoacoustic stack and a coin-shaped cavity, a design inspired by Flitcroft and Symko (2013)...
The purpose of this work was searching of the formation of grain boundaries in metal-ceramics composites at various metal concentrations and sintering temperatures, influence of these boundaries on elastic moduli, coefficient absorption ultrasonic waves (USW) and thermo-conductivity to find the coupling of these properties and to estimate the optimal value of the metal concentration for achieve...
The increased ultrasonic absorption brought about by self-assembly of biomolecules is analyzed for the assembly process from the 20S aggregate to the helical rod of tobacco mosaic virus protein in solution, designated here as the 20S --> P-helix transition. The analysis is based on theoretical developments in ultrasonic relaxation spectrometry presented previously and illustrates the possibilit...
An optoacoustic technique for solutions of strongly light-absorbing analytes at 0.1-0.01 mol l(-1) is proposed. The technique is based on the wide-band forward mode detection of temporal profiles of laser-generated ultrasonic pulses (optoacoustic signals). The leading edge of the signal repeats the distribution of the laser fluence in the medium, which makes it possible to determine its optical...
ZnO ultraviolet (UV)/visible photodiodes were fabricated. The N-In codoped p-type ZnO films were deposited on (111)-oriented silicon substrate by ultrasonic spraying pyrolysis method. It was found the photocurrent approximately 3.9 10 A at a bias of 1 V and a photocurrent to dark current contrast ratio higher than around two orders of magnitude. The photodiodes exhibited two higher responsive r...
Gold nanoparticles with tunable absorption and scattering properties have been developed as contrast agents for various optical imaging techniques. As a hybrid modality that combines the merits of both optical and ultrasonic imaging, photoacoustic (PA) imaging also benefits from the use of these nanoparticles to greatly enhance the contrast for visualization of structures and biomarkers in biol...
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