Results 31 to 40 of about 1,129,305 (370)
矿业科学学报, 2018 In order to improve the classification accuracy of No.3 coal seam roof and floor lithology in Sihe mine, the research of wave impedance and gamma ray pseudo acoustic impedance inversion method of dual mode identifications of coal bearing strata lithology
Li Yuying +5 more
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European Radiology Experimental, 2020 Background To examine in vitro acoustic property of nonalcoholic fatty disease in mouse and human liver to identify nonalcoholic steatohepatitis (NASH). Methods The acoustic impedance (× 106 kg/m2/s) was measured in 35 free fatty acids (FFAs, 500 mmol/L)
Hitoshi Maruyama +8 more
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Acoustic Energy Harvesting of Piezoelectric Ceramic Composites
Energies, 2022 Acoustic energy is an often overlooked but increasingly prevalent source of ambient energy that could be scavenged to power a wide range of devices. Piezoelectric materials are often used, but the tradeoff between acoustic impedance matching and the ...
Jose Figueroa, Margo Staruch
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Acoustic Vector-Corrected Impedance Meter [PDF]
, 2014 We describe the development of a novel instrument intended for the measurement of the acoustical reflection coefficient of materials. The instrument effectively implements a one-port vector-corrected network analyzer in the acoustic, rather than the ...
Pennington, Kyle, Scott, Jonathan B.
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Improving APT Systems’ Performance in Air via Impedance Matching and 3D-Printed Clamp
Sensors, 2023 This paper presents a study on improving the performance of the acoustic piezoelectric transducer system in air, as the low acoustic impedance of air leads to suboptimal system performance.
Liu Liu, Waleed Abdulla
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ON THE USE OF ACOUSTIC IMPEDANCE VALUES TO DETERMINE SEDIMENT PROPERTIES
Acoustic Classification and Mapping of the Seabed 1993,/ Numerous systems have been developed over the past 25 years for remote classification of sediments. The generation of acoustic impedance as a function of depth is the principle behind operation of most normal-incidence acoustic classification systems.
M. Richardson, K. Briggs
semanticscholar +1 more source
Panel of resonators with variable resonance frequency for noise control [PDF]
, 2012 The article focuses on acoustic resonators made of perforated sheets bonded onto honeycomb cavities. This kind of resonators can be used in adverse conditions such as high temperature, dirt and mechanical constraints. For all these reasons, they are, for
Cherrier, Olivier +2 more
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Machines, 2022 In order to apply the nonlinear energy sink (NES) to reduce the low-frequency noise inside a 3D acoustic cavity with an impedance boundary, a two degrees-of-freedom (DOF) dynamic model of the coupled system of one damped acoustic mode of a regular 3D ...
Jianwang Shao +3 more
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ResearchImpedance metasurfaces enable accurate regulation of acoustic fields. However, they can hardly supply a flexible response as such perfect operation is accompanied by stringent requirements on the design of unit cells.
Yu-Ze Tian +4 more
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Acoustic ground impedance meter [PDF]
The Journal of the Acoustical Society of America, 1981 A compact, portable instrument has been developed to measure the acoustic impedance of the ground, or other surfaces, by direct pressure-volume velocity measurement. A Helmholtz resonator, constructed of heavy-walled stainless steel but open at the bottom, is positioned over the surface having the unknown impedance.
openaire +3 more sources