Search results for "SPECTRA"
showing 10 items of 3542 documents
Model, software and database for line-mixing effects in the ν3 and ν4 bands of CH4 and tests using laboratory and planetary measurements-I: N2(and ai…
2006
International audience; Absorption spectra of the infrared ν3 and ν4 bands of CH4 perturbed by N2 over large ranges of pressure and temperature have been measured in the laboratory. A theoretical approach accounting for line mixing is proposed to (successfully) model these experiments. It is similar to that of Pieroni et al. [J Chem Phys 1999;110:7717–32] and is based on state-to-state rotational cross-sections calculated with a semi-classical approach and a few empirical parameters. The latter, which enable switching from the state space to the line space, are deduced from a fit of a single room temperature spectrum of the ν3 band at 50 atm. The comparisons between numerous measured and ca…
Methyl Radical in Clathrate Silica Voids. The Peculiar Physisorption Features of the Guest-Host Molecular Dynamics Interaction.
2016
EPR line shape simulations of CH3/SiO2 clathrates and comparison to CH3/N2O and CH3/SiO2 experiments reveal the motional conditions of the CH3 radical up to the unusual regime of its stability, the high-temperature diffusional regime, at 300 K. In the low-temperature region, the CH3 in clathrates is found to rotate around the in-plane axes even at as low temperatures as 3.8 K. However, nonrotating methyls performing only libration about the C2-axes as well as around the C3-axis are also found, proving the existence of special sites in the clathrate voids that begin to accumulate a significant fraction of methyl radicals at temperatures below approximately 7 K. A distinctive feature in the s…
Assessment of microalgae species, biomass, and distribution from spectral images using a convolution neural network
2022
AbstractEffective monitoring of microalgae growth is crucial for environmental observation, while the applications of this monitoring could also be expanded to commercial and research-focused microalgae cultivation. Currently, the distinctive optical properties of different microalgae groups are targeted for monitoring. Since different microalgae can grow together, their spectral signals are mixed with ambient properties, making estimations of species biomasses a challenging task. In this study, we cultured five different microalgae and monitored their growth with a mobile spectral imager in three separate experiments. We trained and validated a one-dimensional convolution neural network by…
A magnetic look into the protecting layer of Au25 clusters
2016
The field of molecular metal clusters protected by organothiolates is experiencing a very rapid growth. So far, however, a clear understanding of the fine interactions between the cluster core and the capping monolayer has remained elusive, despite the importance of the latter in interfacing the former to the surrounding medium. Here, we describe a very sensitive methodology that enables comprehensive assessment of these interactions. Pulse electron nuclear double resonance (ENDOR) was employed to study the interaction of the unpaired electron with the protons of the alkanethiolate ligands in four structurally related paramagnetic Au25(SR)0 18 clusters (R ¼ ethyl, propyl, butyl, 2-methylpro…
Complete 1H, 13C{1H}, and 31P NMR Spectral Parameters of Some Pyrophosphates
2017
The 1H, 13C{1H}, and 31P NMR spectral parameters of some pyrophosphates were determined in CDCl3. The most complicated 1H spectrum can be solved fully only as (A3MN)R6XX′R6′(MNA3)′, where R6 (= ―N(CH3)2) is coupled only to phosphorus (X). Second-order coupling between phosphorus was found and solved with iterative analysis. A signal shape of one of the carbon resonance cannot be explained only with couplings. Explanation for exceptional shape was searched from molecular modeling results. peerReviewed
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory
2017
We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to $80^\circ$ and energies in excess of 4 EeV ($4 \times 10^{18}$ eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional informa…
Explotación sinérgica de datos multiespectrales y radar para la estimación de variables biofísicas de la vegetación mediante tecnologías de sensorami…
2023
Las variables biofísicas de la vegetación (VBV) son indicadores directos del crecimiento y productividad de los cultivos. Los sistemas de observación de la Tierra (EO–Earth observation) presentan oportunidades sin precedentes para el monitoreo de las variables biofísicas del trigo. Sentinel–2 (S2) es una constelación de satélites que forma parte de las misiones Sentinel del programa Copernicus de EO. El período de revisita, así como su resolución espacial y espectral, han convertido a S2 en un sistema de EO trascendental para el monitoreo de VBV. Los sistemas ópticos de EO se ven limitados con frecuencia por las condiciones climáticas tales como nubosidad o precipitaciones. En este sentido,…
(p,2)-equations resonant at any variational eigenvalue
2018
We consider nonlinear elliptic Dirichlet problems driven by the sum of a p-Laplacian and a Laplacian (a (p,2) -equation). The reaction term at ±∞ is resonant with respect to any variational eigenvalue of the p-Laplacian. We prove two multiplicity theorems for such equations.
Sensors based on MultiSpectral Filter Arrays
2014
International audience; Spectral Filter arrays (SFA) is an emerging technology for multispectral image acquisition. SFAs make possible the use of a compact multispectral sensor to acquire still images or video. One part of this talk will present and compare typical multispectral and color image acquisition systems in order to clearly identify differences underlying SFA technologies. The other part of this talk will show the difficulties and advances that we have made at the University of Bourgogne in the building of such sensors from the design of filters to data processing, such as demosaicing.
Mythologie in Musicis: La alegoría sonora en el Anubis-Nout de Gérard Grisey
2011
El presente artículo plantea un acercamiento a la noción de alegoría sonora a partir de una retrospectiva panorámica de los principios estéticos y del corpus composicional del compositor francés Gérard Grisey, y concretamente de su díptico Anubis-Nout (1983) para clarinete contrabajo solo. La referencia a la mitología egipcia y su simbología no es el único punto de partida explícito de este réquiem posmoderno escrito a la memoria del compositor canadiense Claude Vivier, amigo del autor, a quien está dedicada la pieza, que fue asesinado brutalmente en circunstancias extrañas; muy al contrario, dichas referencias constituyen la fuente de una serie de alegorías asociativas especialmente relaci…