Search results for "DISPERSION"
showing 10 items of 1101 documents
Doped ZnS:Mn nanoparticles obtained by sonochemical synthesis.
2010
A study of sonochemically synthesized ZnS:Mn nanoparticles is presented. The particles prepared at low rf power (about 20 W) and room temperature coalesce to form morphologically amorphous large species (30-100 nm in diameter). As the power is increased in the range from 20 to 70 W, and the solution temperature is raised to 60 to 80 degrees C, finer particles are produced with the size ranging from 2 to 20 nm and improved crystallinity. The results indicate the dispersion of the Mn(2+) ions at near-surface sites in the particles. It is shown that the sonochemically fabricated particles approach the quality of the ones obtained by a standard chemical route and show a reasonable luminescence …
COST 241 intercomparison of nonlinear refractive index measurements in dispersion shifted optical fibres at =1550 nm
1997
COST 241 measurements of the nonlinear refractive index, n/sub 2/, exhibit a large scatter depending on the specific measurement technique. This is largely due to the electrostrictive contribution to the Kerr nonlinearity, as is revealed by the resonant behaviour of n/sub 2/ (with peak values up to 3.9 10/sup -20/ m/sup 2/ W/sup -1/) observed with signal modulation frequencies in the 0.11 GHz range.
La rappresentazione che trasforma. Riflessioni, discussioni e racconti sul progetto Chance
2000
River water quality assessment: a hydrodynamic water quality model for propagation of pollutants
2010
A hydrodynamic river water quality model is presented. The model consists of a quantity and a quality sub-model. The quantity sub-model is based on the Saint Venant equations. The solution of the Saint Venant equations is obtained by means of an explicit scheme based on space-time conservation. The method considers the unification of space and time and the enforcement of flux conservation in both space and time. On the other hand the quality sub-model is based on the advection dispersion equation. Particularly, the principle of upstream weighting applied to finite difference methods is employed. Such a method enables us to reduce the numerical dispersion, avoiding oscillation phenomenon. Th…
Dynamics of pistachio oils by proton nuclear magnetic resonance relaxtion dispersion
2011
A number of pistachio oils were selected in order to test the efficacy of nuclear magnetic resonance relaxation dispersion (NMRD) technique in the evaluation of differences among oils (1) obtained from seeds subjected to different thermal desiccation processes, (2) retrieved from seeds belonging to the same cultivar grown in different geographical areas and (3) produced by using seed cultivars sampled in the same geographical region. NMRD measures relaxation rate values which are related to the dynamics of the chemical components of complex food systems. Results not only allowed to relate kinematic viscosity to relaxometry parameters but also were successful in the differentiation among the…
Impact of GMOs within cropping systems: towards a more systemic approach
2004
International audience
Localized surface plasmons on a torus in the nonretarded approximation
2005
International audience; The dispersion relations and field patterns of the localized surface plasmons of a torus are derived analytically in toroidal coordinates in the nonretarded approximation. Numerical calculations are provided in order to identify the conditions under which a toroidal nanostructure supports a significant magnetic dipole moment at optical frequencies.
Design scaling laws for self-phase modulation-based 2R-regenerators
2006
We report global scaling laws linking the design of SPM-based 2R-regenerators to their ability to reduce amplitude noise and improve the signal extinction ratio.
Effect of Impregnation and Activation Conditions of Al2O3/CuO Supported Monolith Catalysts in the Reduction of NO
1979
Reduction of NO in the presence of CO and Ar was examined on two series of monolithic sheets carrying an active CuO/Al 2 O 3 layer. In the impregnation procedure the ratio of Al 2 O 3 to CuO was varied in a wide range. The texture of the layer and the dispersion of CuO therein was controlled by mercury porosimetry, scanning electron microscopy and secondary ion mass spectrometry (SIMS). It could be established that the surface concentration of CuO determined by SIMS measurements is the most decisive quantity of the catalyst correlating linearly with the conversion of NO.