Theoretical analysis of acoustic stop bands in two-dimensional periodic scattering arrays

Theoretical analysis of acoustic stop bands in two-dimensional periodic scattering arrays.

This paper presents a theoretical analysis of the recently reported observation of acoustic stop bands in two-dimensional scattering arrays [Robertson and Rudy, J. Acoust. Soc. Am. 104, 694 (1998)]. A self-consistent wave scattering theory, incorporating all orders of multiple scattering, is used to obtain the wave transmission. The band structures for the regular arrays of cylinders are comput...

critical discourse analysis of two political speeches in light of bakhtins dialogism

چکیده گفتگوگری باختین نظریه ای است که به تفاوت ها احترام گذاشته و گفتگو را ارج می نهد. رشته های مختلف علوم انسانی همواره از این نظریه بهره جسته اند. با وجود این تنها مطالعات اندکی در زمینه تجزیه و تحلیل نقادانه کلام به نظریه گفتگوگری پرداخته اند. پنداشت تحقیق حاضر بر آن است که احترام به حقوق دیگران از طریق فراهم آوردن شرایط یکسان برای بیان نظریات مختلف یکی از مهمترین مشترکات تحلیل انتقادی گفتم...

Coupled-mode stop bands of acoustic phonons in semiconductor superlattices.

Resonant effects in scattering by periodic arrays

This paper is concerned with resonant effects caused by the scattering of a plane wave by a periodic array of vertical circular cylinders. The scattered field is known to consist of a finite set of plane waves, and an infinite number of evanescent modes which decay exponentially as the perpendicular distance between array and observer is increased. The problem is said to be resonant when the di...

Modeling of acoustic wave scattering from a two-dimensional fracture

We propose two possible representative models for a 2D fracture in reservoirs. The first one simulates the fracture as a low-aspect ratio elliptical cylinder. The inner properties of this elliptical cylinder are assumed to be homogeneous and different from the surrounding medium that is also homogenous. This model can approximately describe the actual shape of fractures observed in the field, a...