Search results for "Absorption"
showing 10 items of 2701 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…
2006
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 calculated spectra under a…
Redshifted Cherenkov Radiation for in vivo Imaging: Coupling Cherenkov Radiation Energy Transfer to multiple Förster Resonance Energy Transfers
2017
AbstractCherenkov Radiation (CR), this blue glow seen in nuclear reactors, is an optical light originating from energetic β-emitter radionuclides. CR emitter 90Y triggers a cascade of energy transfers in the presence of a mixed population of fluorophores (which each other match their respective absorption and emission maxima): Cherenkov Radiation Energy Transfer (CRET) first, followed by multiple Förster Resonance Energy transfers (FRET): CRET ratios were calculated to give a rough estimate of the transfer efficiency. While CR is blue-weighted (300–500 nm), such cascades of Energy Transfers allowed to get a) fluorescence emission up to 710 nm, which is beyond the main CR window and within t…
Historique de l'utilisation des herbicides en France: premières analyses
2010
A data base on the herbicides used in France since 1961 has been built up from the phytosanitary index annually edited by the Association de Coordination Technique Agricole (ACTA). This data base gives the number of active ingredients, associations and commercial products registered every year and for each crop. We also gathered the modes of action, the way of absorption sites and the species susceptibility. Since 1961, 215 molecules have been registered. The number increased regularly with a maximum of 138 in 2002 and only around 100 remain in 2010. The evolution of the number of modes of action available for weed control in wheat is discussed.
Role of intestinal epithelial CD36 in obesity and endotoxemia driven by lipid absorption
2021
Intestinal dysbiosis, increased permeability and inflammation are the hallmarks in obese patients, highlighting the role of small intestine beyond providing with calories. CD36 is a ubiquitous scavenger receptor that exhibits high binding affinity for long-chain fatty acids and is highly expressed in enterocytes, endothelial and immune cells. Interestingly, CD36-/- mice and humans with CD36 polymorphisms have an impaired synthesis of triglyceride-rich lipoprotein (TRL). To evaluate the role of CD36 expressed by intestinal-epithelial cells (IEC) in obesity, we conducted experiments on male and female mice deleted in CD36 in IEC (ENT-KO) and control mice (ENT-FL), under standard and high-fat …
Recently identified microbial guild mediates soil N2O sink capacity
2015
Interdiction des procédures d'exécution. Absorption de la société caution inopposable à un créancier de la société débitrice. Possibilité de saisie d…
2021
International audience; (Com. 7 oct. 2020, n° 19-14.755, arrêt n° 609 FS-P+B, Sté Almendricos et a. c/ Sté Crédit foncier de France, D. 2021. 458, obs. G. Sebban ; Rev. sociétés 2020. 709, obs. F. Reille ; JCP 2020. 1220)
Recent developments in the acoustical properties of perforated and porous materials containing dead-end pores
2017
It was shown recently in Nevers, France, Sherbrooke, Canada and Salford, UK, that porous materials with semi-opened pores or materials with open pores bearing lateral cavities or resonators at the microscopic scale of the pores can result in peculiar sound absorption properties. Various examples of these materials can be found in engineering and in everyday life including bio-based materials. The cavities and resonators can be assimilated to dead-end pores, which are opened at one end and closed at the other. The dead-end pores are known to geophysicists. We studied them more recently in the field of engineering acoustics where the saturating fluid is air. The closed ends prevent the fluid …
Acoustical properties of air-saturated porous material with periodically distributed dead-end pores
2015
International audience; A theoretical and numerical study of the sound propagation in air-saturated porous media with straight main pores bearing lateral cavities (dead-ends) is presented. The lateral cavities are located at " nodes " periodically spaced along each main pore. The effect of periodicity in the distribution of the lateral cavities is studied, and the low frequency limit valid for the closely spaced dead-ends is considered separately. It is shown that the absorption coefficient and transmission loss are influenced by the viscous and thermal losses in the main pores as well as their perforation rate. The presence of long or short dead-ends significantly alters the acoustical pro…
On the Schwarzschild Effect in 3D Two‐Photon Laser Lithography
2019
International audience; The two‐photon Schwarzschild effect in photoresists suitable for 3D laser lithography is revisited. The study ranges over seven orders of magnitude in exposure time (from 1 µs to 10 s) and investigates a wide variety of different photoresist compositions. For short exposure times (“regime I”), the laser power at the polymerization threshold can scale with the inverse square root of the exposure time, as naively to be expected for two‐photon absorption. Substantial deviations occur, however, for low photoinitiator concentrations. For intermediate exposure times (“regime II”), a Schwarzschild‐type of behavior is found, as discussed previously. For very long exposure ti…
Single crystal EXAFS at high pressure
2000
Abstract We present a new technique for structure characterization under high pressure conditions. The use of an undulator beam of the third-generation ESRF source of synchrotron radiation has enabled the first single crystal EXAFS experiments at high pressure using a diamond anvil cell as pressure generator. Taking advantage of the linear polarization of X-rays the technique becomes an orientation-selective probe of the local structure of materials. We describe the principle of the technique and some applications.