Search results for "Small"
showing 10 items of 2441 documents
A structural comparison of halloysite nanotubes of different origin by Small-Angle Neutron Scattering (SANS) and Electric Birefringence
2018
The structure of halloysite nanotubes (Hal) from different mines was investigated by Small-Angle Neutron Scattering (SANS) and Electric Birefringence (EBR) experiments. The analysis of the SANS curves allowed us to correlate the sizes and polydispersity and the specific surfaces (obtained by a Porod analysis of the SANS data) of the nanotubes with their specific geological setting. Contrast matching measurements were performed on patch Hal (from Western Australia) in order to determine their experimental scattering length density for a more precise analysis. Further characterization of the mesoscopic structure of Hal was carried out by Electric Birefringence (EBR), which allowed to study th…
Physicochemical Investigation of Nanostructures in Liquid Phases: Ytterbium Nitrate Ionic Clusters Confined in Ytterbium Bis(2-ethylhexyl) Sulfosucci…
2007
The confinement of finite amounts of ytterbium nitrate in the nanoscopic space of ytterbium bis(2-ethylhexyl)sulfosuccinate (Yb(DEHSS) 3 ) reversed micelles dispersed in n-heptane has been investigated by UV-vis-NIR, FT-IR, and SAXS. The analysis of the experimental data is consistent with the hypothesis that Yb(NO 3 ) 3 is distributed among reversed micelles as small size ionic clusters surrounded by the Yb 3+ surfactant counterions and anionic heads while the surfactant alkyl chains point toward the solvent medium. As a consequence of confinement and interfacial effects, the ionic clusters display photophysical properties different from those in the bulk state or isolated species. Moreove…
Physicochemical Investigation of the Solubilization of Ytterbium Nitrate in AOT Reverse Micelles and Liquid Crystals
2006
A wide investigation of the solubilization of the water-soluble salt Yb(NO3)(3) in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles and AOT liquid crystals has been carried out. After saturation of water/AOT/organic solvent w/o microemulsions with pure Yb(NO3)(3), the Yb(NO3)(3)/AOT composites were prepared by complete evaporation under vacuum of the volatile components (water and organic solvent) of the salt-containing microemulsions. It was observed that these composites can be totally dissolved in pure n-heptane or CCl4, allowing the solubilization of a noticeable amount of Yb(NO3)(3) in quite dry apolar media. By UV-vis-NIR, FT-IR, and H-1 NMR spectroscopies, some informati…
Study on the initial stages of water corrosion of fluorozirconate glasses
2004
Abstract The surface corrosion process associated with the hydrolysis of fluorozirconate glass, ZBLAN (53ZrF 4 , 20BaF 2 , 20NaF, 4LaF 2 , 3AlF 3 ) was investigated using X-ray photoelectron spectroscopy (XPS), grazing-incidence small angle X-ray scattering (GISAXS), X-ray reflectivity (XRR) and scanning electron microscopy (SEM). After a short exposure period (25 min) of the glass surface to deionized water the XPS data indicate an increase of the oxygen content accompanied by a decrease of fluorine concentration. The analysis of the chemical bonding structure identified the predominant surface reaction products as zirconium hydroxyfluoride and oxyfluoride species. The second most abundant…
eISP: a Programmable Processing Architecture for Smart Phone Image Enhancement
2009
4 pages; Today's smart phones, with their embedded high-resolution video sensors, require computing capacities that are too high to easily meet stringent silicon area and power consumption requirements (some one and a half square millimeters and half a watt) especially when programmable components are used. To develop such capacities, integrators still rely on dedicated low resolution video processing components, whose drawback is low flexibility. With this in mind, our paper presents eISP {--} a new, fully programmable Embedded Image Signal Processor architecture, now validated in {TSMC 65nm} technology to achieve a capacity of {16.8 GOPs} at {233 MHz}, for {1.5 mm$^2$} of silicon area and…
High-resolution infrared spectroscopy and analysis of the v2=v4 bending dyad and v3 stretching fundamental of ruthenium tetroxide
2017
International audience; RuO4 is a heavy tetrahedral molecule which has practical uses for several industrial fields. Due to its chemicaltoxicity and the radiological impact of its 103 and 106 isotopologues, the possible remote sensing of this compound in theatmosphere has renewed interest in its spectroscopic properties. We investigate here for the first time at high resolutionthe bending dyad region in the far IR and the line intensities in the 3 stretching region. Firstly, new high resolutionFTIR spectra of the bending modes region in the far infrared have been recorded at room temperature, using a speciallyconstructed cell and an isotopically pure sample of 102RuO4. New assignments and e…
Thermodiffusion anisotropy under a magnetic field in ionic liquid-based ferrofluids
2021
International audience; Ferrofluids based on maghemite nanoparticles (NPs), typically 10 nm in diameter, are dispersed in an ionic liquid (1-ethyl 3-methylimidazolium bistriflimide - EMIM-TFSI). The average interparticle interaction is found to be repulsive by small angle scattering of X-rays and of neutrons, with a second virial coefficient A2 = 7.3. A moderately concentrated sample at Φ = 5.95 vol% is probed by forced Rayleigh scattering under an applied magnetic field (up to H = 100 kA m-1) from room temperature up to T = 460 K. Irrespective of the values of H and T, the NPs in this study are always found to migrate towards the cold region. The in-field anisotropy of the mass diffusion c…
Brain lateralization probed by water diffusion at the atomic to micrometric scale
2019
International audience; Combined neutron scattering and diffusion nuclear magnetic resonance experiments have been used to reveal significant interregional asymmetries (lateralization) in bovine brain hemispheres in terms of myelin arrangement and water dynamics at micron to atomic scales. Thicker myelin sheaths were found in the left hemisphere using neutron diffraction. 4.7 T dMRI and quasi-elastic neutron experiments highlighted significant differences in the properties of water dynamics in the two hemispheres. The results were interpreted in terms of hemisphere-dependent cellular composition (number of neurons, cell distribution, etc.) as well as specificity of neurological functions (s…
Fermentation Products of Commensal Bacteria Alter Enterocyte Lipid Metabolism
2020
eferred to byJia Wen, John F. RawlsFeeling the Burn: Intestinal Epithelial Cells Modify Their Lipid Metabolism in Response to Bacterial Fermentation ProductsCell Host & Microbe, Volume 27, Issue 3, 11 March 2020, Pages 314-316; International audience; Despite the recognized capacity of the gut microbiota to regulate intestinal lipid metabolism, the role of specific commensal species remains undefined. Here, we aimed to understand the bacterial effectors and molecular mechanisms by which Lactobacillus paracasei and Escherichia coli regulate lipid metabolism in enterocytes. We show that L-lactate produced by L. paracasei inhibits chylomicron secretion from enterocytes and promotes lipid stora…
Determination of taste-active compounds of a bitter camembert cheese by omission tests
2001
The taste-active compounds of a Camembert cheese selected for its intense bitterness defect were investigated. The water-soluble fraction (WSE) was extracted with pure water and fractionated by successive tangential ultrafiltrations and nanofiltration. The physicochemical assessment of these fractions led to the construction of a model WSE which was compared by sensory evaluation to the crude water-soluble extract, using a panel of 16 trained tasters. As no significant difference was perceived, this model WSE was then used directly or mixed with other cheese components for omission tests. Among the main taste characteristics of the WSE (salty, sour, umami and bitter), bitterness was found t…