acoustic shadow


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acoustic shadow

[ə′küs·tik ′shad·ō]
(acoustics)
A region immediately behind an object placed in the path of a sound wave whose wavelength is much smaller than the object, in which the initial sound wave is cut off by the object and the sound intensity is determined by the diffraction and interference of sound waves bent around the obstacle.
References in classic literature ?
If you stand in an acoustic shadow there is one direction from which you will hear nothing.
19] The implant is visible in the transverse plane by its characteristic posterior acoustic shadow.
The possible solution methods are to operate the probe through multiple sections on nodules to avoid acoustic shadow interference.
Such air defects, whose size a is larger than the focal spot dF of the probe ultrasound beam (a^lOdf), generate an acoustic shadow in the volume under the inclusion.
The black circular feature in the center is the acoustic shadow of an air-filled anomaly that is more or less centered on the die.
Is one of the best visualized structures described at the transverse axis as a hypoechoic structure with respect to the vocal cords, followed by an acoustic shadow corresponding to the airway (Fig.
It also includes aspects of technology, culture, and physical phenomena that influenced the outcomes or documentation of the war, such as the early ambrotype photograph, influential newspapers, the practice on conscription, and the phenomenon of acoustic shadow.
Barriers protect the receiver from direct airborne sound waves by reducing the noise level in the acoustic shadow zone.
Entertainment was provided by Michael and Leigh Ann Carley of Acoustic Shadow and Rain Jaudon and Cheri Salvetti of Rhythm and Rain.
Millili stated, "Regardless of observer experience in burn evaluation, obliteration of the dermal/fat interface and widening of the dermal acoustic shadow provides reliable markers of deep thermal injury.
They are ill defined, have a heterogeneous or mixed echo appearance internally, show invasion of adjacent tissue planes and sometimes produce a posterior acoustic shadow.
Access through the entrance of the thorax enabled the visualization of the masses in the topographical area of the sternal lymph node with the following features: heterogeneous echogenicity and echotexture, irregular margins, calcifications forming an acoustic shadow.
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