Search results for "RAYLEIGH SCATTERING"
showing 10 items of 75 documents
Anharmonic elasticity theory for sound attenuation in disordered solids with fluctuating elastic constants
2010
1997
We have determined by forced Rayleigh scattering the diffusion coefficients of photo-labeled polystyrene micronetwork spheres (radii ≤ 10 nm) in melts of linear polyvinylmethylether (M W ≤ 40000 g/mol) at temperatures of 20-80°C. An expected slippage of the spheres through the meshes of the entanglement network appears possible but is still within the experimental uncertainty of our results.
Probing Poly(n-butyl-methacrylate) Latex Film via Diffusion of Hydrophilic and Hydrophobic Dye Molecules
2003
In the study of holographic grating relaxation (forced Rayleigh scattering, FRS) in nascent latex films we examined poly(n-butyl methacrylate) films using two complementary diffusing probes: a hyd...
Dynamics of Copolymer Micelles in a Homopolymer Melt: Influence of the Matrix Molecular Weight
2000
We have studied the dynamics of styrene−isoprene (SI) block copolymer micelles in a matrix of linear entangled polyisoprene (PI) chains, using forced Rayleigh scattering (FRS) and dynamic mechanica...
On the statistical properties of the capacity of sparse multipath fading channels
2014
Most existing works in wireless communications assume rich scattering. However, there is growing experimental evidence that physical wireless channels can exhibit a sparse structure. By assuming an asymmetric Doppler power spectral density (PSD), we can model and simulate sparse channels by using a finite sum of weighted complex harmonic functions, also called sum of cisoids (SOC). In this paper, we focus on the analysis of the statistical properties of the instantaneous capacity of sparse SOC-based multipath fading channels under line-of-sight (LOS) conditions. The probability density function (PDF), the cumulative distribution function (CDF), the level-crossing rate (LCR), and the average…
Self-consistent Euclidean-random-matrix theory
2019
Hyper-Rayleigh scattering and two-photon luminescence of phenylamine- indandione chromophores
2012
Based on results of quantum chemical (QC) screening, we put under research several phenylamine indane-1,3-dione derivatives including octupolar NLO chromophore A3BI. According to these calculations, molecular first hyperpolarizability (βHRS) should be enhanced upon replacement of methyl substituents with phenyl groups. Surprisingly, βHRS values obtained in our measurements by hyper-Rayleigh scattering (HRS) are much higher than one could expect from QC. Bearing in mind that two-photon luminescence (TPL) is usual cause for overestimation of βHRS in HRS measurements, we have accomplished investigations of TPL properties of these compounds. All investigated triphenylamine derivatives exhibit s…
Synthetic aperture microscopy using off-axis illumination and polarization coding
2007
A new method to improve the resolution of optical imaging systems beyond the classical Rayleigh resolution limit is presented. The technique relies on synthetic aperture generation in three stages. The first one (encoding stage) uses an illumination procedure that combines both on-axis and off-axis illumination beams with different polarization states onto the object. After the imaging system, a second stage (decoding stage) allows the recovering of the encoded spatial-frequency object information by means of an interferometric configuration based on the polarization coding carried out in the previous stage. Finally, a third stage (digital post-processing stage) is used to generate a synthe…
Real time monitoring of water level and temperature in storage fuel pools through optical fibre sensors
2017
AbstractWe present an innovative architecture of a Rayleigh-based optical fibre sensor for the monitoring of water level and temperature inside storage nuclear fuel pools. This sensor, able to withstand the harsh constraints encountered under accidental conditions such as those pointed-out during the Fukushima-Daiichi event (temperature up to 100 °C and radiation dose level up to ~20 kGy), exploits the Optical Frequency Domain Reflectometry technique to remotely monitor a radiation resistant silica-based optical fibre i.e. its sensing probe. We validate the efficiency and the robustness of water level measurements, which are extrapolated from the temperature profile along the fibre length, …
On the Statistical Properties of Equal Gain Combining over Mobile-to-Mobile Fading Channels in Cooperative Networks
2010
Paper presented at the 2010 IEEE International Conference on Communications (ICC), Cape Town. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. Paper also available from the publisher: http://dx.doi.org/10.1109/ICC.2010.5501898 This article deals with the statistical analysis of equal gain combining (EGC) over mobile-to-mobile (M2M) fading channels in a dual-hop amplify-and-forward relay network. Here, we…