Acoustic interferometer

About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.

Acoustic leakage in electromagnetic waveguides made from piezoelectric materials

Abstract: We study the propagation of coupled acoustic and electromagnetic waves in a piezoelectric plate waveguide embedded in two half-spaces of another dielectric material. It is shown that certain waves are guided electromagnetically but not so acoustically and that these waves are effectively damped waves with acoustic leakage of energy. An estimate of the acoustic radiation damping is given.

Arctic acoustics ultrasonic modeling studies

Abstract: : A unique collection of laboratory ultrasonic modeling results are presented revealing and characterizing hidden pulsed seismoacoustic wave phenomena from 3-D range dependent liquid/solid boundaries. The research succeeded in isolating and identifying low-frequency (10-500 Hz) transmission loss mechanisms and provided physical insight into Arctic acoustic problems generally beyond the state-of-the-art of theoretical and numerical analysis. The ultrasonic modeling studies dealt with controversial issues and existing discrepancies on seismo-acoustic waves at water/ice interface, sea-ice thickness determination, low-frequency transmission loss, and bottom leaky Rayleigh waves. The areas investigated include leaky Rayleigh waves at water/ice interface, leaky flexural waves in floating ice plates, effects of dry/wet cracks in sea- ice on plate waves and near-grazing acoustic waves, edge waves in floating plates, low-frequency backscatter from ice keel-width resonances, conversion of underwater acoustic waves into plate waves by keels, nondispersive flexural wave along apex of small-angle solid wedge, Scholte and leaky Rayleigh waves along apex of immersed 90 ice wedge, backscatter from trailing edge of floes, floating plate resonances associated with near-grazing underwater acoustic waves, acoustic coupling between adjacent floes, and multiple bottom leaky Rayleigh wave components in water layer over solid bottom.

Excitation of acoustic waves in plasmas

Abstract: This paper repo rt s early re s ults in an experime nt al s tudy to d ete rmine the e ffects of perturbing weak lyi(lnized gaseous plasmas with acoustic waves e m a natin g from tran sdu cers tl, a t ope rate in Ihe audio and ultraso ni c freque ncy ranges . Compact louds pe ake rs incorporated int o cylindri c al plas ma discha rge tubes provid e the source of acous ti c s igna ls. Modulation of elec tromag neti c wav f'S by th e aco us ti ca ll y-disturbed p las ma is meas ure d in a unique rec ta ngular cavity whose output is de tec ted and fed to a wave a na lyzer. Res ult a nt wave-a na lyze r responses indi cate that the co lli sion fre qu e ncy is modula te d in addi tion 10 th e plas ma frequ e ncy, and s ugges t that the varia tions in bot h arc proporlional to the magnitu de of louds peaker diaphragm de flec tion , as pre di c te d by simple acolls ti c theory. Knowin g that two forms of modulation occu r s im ult a neous ly, a ca libration sc he me was deve loped to se pa ra te the var iation tJ.J;, in the p lasma freque ncy from the tot a l res ponse . Meas ure ments to dat f' ind icate that tJ.N, /N,.= C1N/N (whe re N, and N are elec tron and ne utra l-molecul e dens ities, respect ive ly) for s li ghtl yionize d gases whi c h are s ubjec le d to low-frequency press ure variation in th e order of 10-5 mm Hg, a nd th a t s uc h variation s produce pl as mafreq ue ncy perturbalions of 0 140 kc/s a t plas ma frequ enc ies up to 800 Mc/s_

Application of Surface Acoustic Waves

Abstract: 弾性表面波は機器の小型化と, 波の発生・検出・制御等の容易さという点で機能素子として多くの適用が考えられる.本文は線形素子としてのフィルター, およびフィルターなどの特性改善に将来重要性を増すと思われる増幅素子, 非線形効果の積極的応用としてのコンボルバー, イメージ素子などについて最近の動向を述べる.