Focusing and Scanning of Acoustic Waves in Solids

Electroacoustic Waves in a Ferroelectric Crystal with of a Moving System of Domain Walls

“…To join the domain fields in the frame of the DW at rest on the interface yd = in the nonrelativistic quasistatic approximation, we employ the conventional continuity conditions [Auld, 1973] …”

Generation of Cumulative Sum Frequency and Difference Frequency Acoustic Waves in a Two-Dimensional Hard-Walled Waveguide

“…Because there is a condition of phase matching between the two partial longitudinal waves of the ( f G , l) mode, the oz-axis components of two wave vectors are of the same magnitude. The formal solution of two partial longitudinal waves of the ( f G , l ) mode is given by [4,5] …”

“…For simplicity, the sign, ( f G , l), is used to indicate the lth fundamental mode with frequency f G (i"1, 2). According to the partial wave analysis method [5], the lth fundamental mode with frequency f G and angular frequency G consists of two partial longitudinal waves which are re#ected at the upper and lower walls of the waveguide. Because there is a condition of phase matching between the two partial longitudinal waves of the ( f G , l) mode, the oz-axis components of two wave vectors are of the same magnitude.…”

Mode Theory of the Nonspecular Reflection Phenomena of a Gaussian Ultrasonic Beam Incident onto an Elastic Plate

“…The coefficient an(z) of the excited mode is governed by a mode amplitude equation, obtained from the reciprocity relation and the onhoganality condition of eigenmüdes [12,13], 4 P n (d~ + ik:n) an (z) = fn (z) (4) where P n is the average power flow associated with the nth guided mode and fn is the exciting force applied on the liquid/solid interface (y = bl2) from both the incident and In the case where the liquid is nonviscous, only normal stress Tyy is transferred onto the surface of the guide. Using the boundary conditions (2) and substituting Eq.…”

“…2 presents the reflected profiles of a 12 mm-wide Gaussian beam incident from water onto an aluminium substrate (VJ = 6290 m/s, v5 = 3280 m/s) at the Rayleigh angle eR = 29°. When the value of hR = aRwo increases with the frequency [12], the reflected profiles become nonspecular and undergo a lateral displacement. Similar phenomena are observed in the beams reflected from elastic plates.…”