Results 351 to 360 of about 1,129,305 (370)
Some of the next articles are maybe not open access.
Impedance‐Matching Wavefront‐Transformation Lens Based on Acoustic Metamaterials
Advanced Materials & Technologies, 2018A broadband, low‐loss, and impedance‐matching wavefront‐transformation lens in acoustics is proposed. Different from the previous planar gradient‐index lens in which the refraction index changes in one direction, the refraction index in the proposed lens
Lin Bai +6 more
semanticscholar +1 more source
Acoustic Impedance of Small Orifices
The Journal of the Acoustical Society of America, 1935Data are presented giving the measured a.c. acoustic reactance and resistance for a number of circular orifices varying in diameter from 1 cm down to 0.034 cm, and for a rectangular orifice 1.9 cm×0.075 cm. The measurements were made for various particle velocities, the corresponding Reynolds numbers varying from 0.1 to 1000, roughly.
openaire +2 more sources
Measurement of Acoustic Impedance of Skin
1978It is important to know the characteristics of the acoustic impedance of a living tissue in order to diagnose with ultrasonic equipment or to design the equipment. Especially, in the immersion method of ultrasonic diagnosis, if strong reflections are produced from mis-matched interface between the skin and the water-bag and that between transducer and ...
A. Matsuda +5 more
openaire +2 more sources
High transmission acoustic focusing by impedance-matched acoustic meta-surfaces
, 2016Impedance is an important issue in the design of acoustic lenses because mismatched impedance is detrimental to real focusing applications. Here, we report two designs of acoustic lenses that focus acoustic waves in water and air, respectively.
R. Jahdali, Ying Wu
semanticscholar +1 more source
Acoustic impedance of an annular capillary
The Journal of the Acoustical Society of America, 1975The behavior of an acoustic impedance formed by a capillary of annular cross section was investigated. The configuration used in previous work consisted of a cylindrical rod spaced concentrically within a cylindrical tube. Experimentally, this configuration was found to have an impedance magnitude which remained reasonably constant with frequency up to
openaire +2 more sources
A broadband acoustic metamaterial with impedance matching layer of gradient index
, 2017Narrowband transmission of some acoustic metamaterials limits their device applications. Here, we propose and demonstrate a broadband acoustic metamaterial comprising a space coiling structure by introducing an impedance-matching layer between air and ...
Yi S. Ding +3 more
semanticscholar +1 more source
Structure-constrained relative acoustic impedance using stratigraphic coordinates
, 2015Acoustic impedance inversion involves conversion of seismic traces to a reflection coefficient time series and then into acoustic impedance. The usual assumption for the transformation of poststack seismic data into impedance is that seismic traces can ...
Parvaneh Karimi
semanticscholar +1 more source
Acoustic Impedance Transformation-Reply
Archives of Otolaryngology - Head and Neck Surgery, 1987In Reply .—Dr Kimberley is incorrect when he states that "a mechanical/acoustical system such as the external ear is quite incapable of impedance transformation, at any frequency." One way to model the acoustic function of the external ear is as a small horn whose mouth contacts the low specific impedance air of the external environment (41.5 acoustic ...
openaire +2 more sources
Acoustic impedance matching device
The Journal of the Acoustical Society of America, 1982A impedance matching window for an ultrasound transducer comprises a periodic array of stepped structures. Each stepped structure comprises a plurality of parallel matching strips disposed side-by-side on an active surface of a piezoelectric ceramic.
openaire +2 more sources
Manfred Schroeder and Acoustical Impedance
2014Manfred Schroeder was a man with many interests. Between the years 1966 and 1967, he invented devices for measuring the surface impedance of materials as well as the vocal tract impedance. At the time, he would only consider normal incidence; however, he already anticipated that the behavior of materials at grazing incidence would have relevance to ...
Roland Kruse, Volker Mellert
openaire +2 more sources