Search results for "Infrared"
showing 10 items of 2110 documents
The lineshape of the electronic spectrum of the green fluorescent protein chromophore, part I: gas phase.
2014
The vibronic spectra of the green fluorescent protein chromophore analogues p-hydroxybenzylidene-2,3-dimethylimidazolinone (HBDI) and 3,5-tert-butyl-HBDI (35Bu) are similar in the vacuum, but very different in water or ethanol. To understand this difference, we have computed the vibrationally resolved solution spectra of these chromophores, using the polarizable continuum model (PCM) to account for solvent effects on the (harmonic) potential energy surfaces (PES). In agreement with experiment, we found that the vibrational progression increases with the polarity of the solvent, but we could neither reproduce the broadening, nor the large difference between the absorption spectra of HBDI and…
How subtle is the "terroir" effect? Chemistry-related signatures of two "climats de Bourgogne".
2014
The chemical composition of grape berries is influenced by various environmental conditions often considered to be representative of a "terroir". If grapes from a given terroir are assumed to reflect this origin in their chemical compositions, the corresponding wine should also reflect it. The aim of this work was therefore to reveal the "terroir" expression within the chemodiversity of grapes and related wines, using ultrahigh-resolution mass spectrometry. Grapes and corresponding wines, from two distinct - though very proximate - terroirs of Burgundy were analyzed over three vintages (2010, 2011 and 2012). Ultrahigh-resolution mass spectrometry and ultra-high performan…
LST retrieval algorithm adapted to the Amazon evergreen forests using MODIS data
2018
Abstract Amazonian tropical forests play a significant role in global water, carbon and energy cycles. Considering the importance of this biome and climate change projections, the monitoring of vegetation status of these rainforests becomes of significant importance. In this context vegetation temperature is presented as a key variable linked with plant physiology. In particular some studies showed the relationship between this variable and the CO2 absorption capacity and biomass loss of these tropical forests proving the potential use of vegetation temperature in the monitoring of the vegetation status. Nevertheless, the use of thermal remote sensing data over tropical forests still has so…
Density Functional Theory Calculated Raman Spectra of Ergocalciferol (Vitamin D2) and Cholecalciferol (D3)
2021
Density functional theory (DFT)-calculated Infrared and Raman spectra of Vitamin D2 and D3 are presented. The calculated results are compared with each other and with available experimental data. Applicability of Raman spectra for non-invasive optical Vitamin D sensors is discussed.
Isotopically (δ13C and δ18O) heavy volcanic plumes from Central Andean volcanoes: a field study
2017
International audience; Stable isotopes of carbon and oxygen in volcanic gases are key tracers of volatile transfer between Earth's interior and atmosphere. Although important, these data are available for few volcanoes because they have traditionally been difficult to obtain and are usually measured on gas samples collected from fumaroles. We present new field measurements of bulk plume composition and stable isotopes (δ13CCO2 and δ18OH2O+CO2) carried out at three northern Chilean volcanoes using MultiGAS and isotope ratio infrared spectroscopy. Carbon and oxygen in magmatic gas plumes of Lastarria and Isluga volcanoes have δ13C in CO2 of +0.76‰ to +0.77‰ (VPDB), similar to slab carbonate;…
Hot-spot detection and characterization of strombolian activity from MODIS infrared data
2014
Identifying and characterizing strombolian activity from space is a challenging task for satellite-based infrared systems. Stromboli volcano is a natural laboratory that offers a unique opportunity for refining thermal remote-sensing applications that involve transient phenomena and small to moderate hot-spots. A new simple and fast algorithm gave us the opportunity to revisit the MODIS-derived thermal output at Stromboli volcano over the last 13 years. The new algorithm includes both night-time and daytime data and shows high performance with the detection of small-amplitude thermal anomalies ( 1000 MW). The ...
On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (E…
2016
[EN] A web-based database of voltammograms is presented for characterizing artists' pigments and corrosion products of ceramic, stone and metal objects by means of the voltammetry of immobilized particles methodology. Description of the website and the database is provided. Voltammograms are, in most cases, accompanied by scanning electron microphotographs, X-ray spectra, infrared spectra acquired in attenuated total reflectance Fourier transform infrared spectroscopy mode (ATR-FTIR) and diffuse reflectance spectra in the UV-Vis-region. For illustrating the usefulness of the database two case studies involving identification of pigments and a case study describing deterioration of an archae…
Partial least squares-near infrared determination of pesticides in commercial formulations
2007
Abstract A solvent free, fast and environmentally friendly near infrared-based methodology (NIR) was developed for pesticide determination in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples and a multivariate calibration model (partial least squares, PLS) to determine the active principle concentration in commercial formulations. The PLS calibration set was built on using the spiked samples by mixing different amounts of pesticide standards and powdered samples. Buprofezin, Diuron and Daminozide were used as test analytes. Concentration of Buprofezin in the samples was calculated employing a 4-fact…
A FTIR study on low hydration saccharide amorphous matrices: Thermal behaviour of the Water Association Band
2011
Abstract We report a study on the thermal behaviour of the infrared Water Association Band (WAB) in dry binary saccharide–water systems (containing trehalose, sucrose, maltose, and raffinose). This is a follow-up of preceding studies on analogous carboxymyoglobin-saccharide–water ternary systems, which pointed out a mutual protein-matrix influence (coupling). A comparison between binary and ternary systems, for all the saccharides studied, evidences a reduction in the residual water content in the latter and, except for trehalose, a sizable modification in the thermal behaviour, which is discussed in terms of structure and hydrogen bonding properties of the sugars. The study allowed us also…
Sources optiques infrarouges impulsionnelles ultra-courtes et spectralement ultra-larges générées par effet Raman dans les fibres creuses
2019
Gas-filled Hollow-Core Photonic Crystal Fibers (HC-PCF) are efficient tools regarding ultra-wide and coherent optical frequency combs by Stimulated Raman Scattering (SRS). Coherence is reached thanks to highly transient regime as it allows amplification, from quantum to macroscopic level, of a unique spatial and temporal mode (TSM). This results in the generation of Stokes waves with a well-determined phase. The present work details on which time scale coherence can subsist, between two consecutive pulses. The possibility of making a new kind of mode-lock is studied. Then the extreme versatility of gas-filled HC-PCF is illustrated by presenting different kind of new laser sources, exploitin…