Inicio Nosotros Búsquedas
Buscar en nuestra Base de Datos:     
Autor: Ryzhik, Leonid (Comienzo)
2 registros cumplieron la condición especificada en la base de información BIBCYT. ()
Registro 1 de 2, Base de información BIBCYT
Publicación seriada
Referencias AnalíticasReferencias Analíticas
Autor: Bal, Guillaume ; Ryzhik, Leonid
Título: Difusion Aproximation of Radiactive Transfer Problem with Interfaces
SIAM Journal on Applied Mathematics Vol. 60, no. 6 May/June 2000
Información de existenciaInformación de existencia

Palabras Claves: Palabras: DIFFUSION APPROXIMATION DIFFUSION APPROXIMATION, Palabras: INTERFACE CONDITIONS INTERFACE CONDITIONS, Palabras: RADIATIVE TRANSFER RADIATIVE TRANSFER

Resumen
RESUMEN

RESUMEN

 

We derive the diffusion approximation of transport equations with discontinuities at interfaces. The transport equations model the energy density of acoustic waves. The waves are reflected and transmitted at the interface between different media, which leads to discontinuities of the energy density across the interface. The diffusion approximation, which is valid inside each region, is not correct at the vicinity of the interface. However, using interface layer analysis, we prove that the transport solution can be approximated by a diffusion term plus an interface layer which decays exponentially fast. We derive systematically the correct form of the interface conditions for this diffusion term.

Registro 2 de 2, Base de información BIBCYT
Publicación seriada
Referencias AnalíticasReferencias Analíticas
Autor: Papanicolaou, George ; Ryzhik, Leonid ; Solna, Knut
Título: Statistical Stability in Time Reversal
Páginas/Colación: pp. 1133 - 1155
Url: Ir a http://epubs.siam.org/sam-bin/dbq/article/41110http://epubs.siam.org/sam-bin/dbq/article/41110
SIAM Journal on Applied Mathematics Vol. 64, no. 4 April/June 2004
Información de existenciaInformación de existencia

Palabras Claves: Palabras: LIOUVILLE--ITO EQUATION LIOUVILLE--ITO EQUATION, Palabras: RANDOM MEDIUM RANDOM MEDIUM, Palabras: STOCHASTIC FLOW STOCHASTIC FLOW, Palabras: TIME REVERSAL TIME REVERSAL, Palabras: WAVE PROPAGATION WAVE PROPAGATION

Resumen
When a signal is emitted from a source, recorded by an array of transducers, time-reversed, and re-emitted into the medium, it will refocus approximately on the source location. We analyze the refocusing resolution in a high frequency remote-sensing regime and show that, because of multiple scattering in an inhomogeneous or random medium, it can improve beyond the diffraction limit. We also show that the back-propagated signal from a spatially localized narrow-band source is self-averaging, or statistically stable, and relate this to the self-averaging properties of functionals of the Wigner distribution in phase space. Time reversal from spatially distributed sources is self-averaging only for broad-band signals. The array of transducers operates in a remote-sensing regime, so we analyze time reversal with the parabolic or paraxial wave equation.

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

UCLA - Biblioteca de Ciencias y Tecnologia Felix Morales Bueno

Generados por el servidor 'bibcyt.ucla.edu.ve' (3.135.188.108)
Adaptive Server Anywhere (07.00.0000)
ODBC
Sesión="" Sesión anterior=""
 ejecutando Back-end Alejandría BE 7.0.7b0 ** * *
3.135.188.108 (NTM) bajo el ambiente Apache/2.2.4 (Win32) PHP/5.2.2.
usando una conexión ODBC (RowCount) al manejador de bases de datos..
Versión de la base de información BIBCYT: 7.0.0 (con listas invertidas [2.0])

Cliente: 3.135.188.108
Salida con Javascript
** Back-end Alejandría BE 7.0.7b0 *