The control of catalytic performance of rutile-type Sn/V/Nb/Sb mixed oxides, catalysts for propane ammoxidation to acrylonitrile

This paper describes the effect of the composition of rutile-type Sn/V/Nb/Sb mixed oxides catalysts on the catalytic performance in the gas-phase ammoxidation of propane to acrylonitrile. The variation in the atomic ratio between components in catalysts is the key for the control of activity and selectivity. In samples with atomic composition Sn/V/Nb/Sb 1/0.2/1/x (0 x 5) and 1/0.2/y/3 (0 y 3) several compounds formed, i.e., SnO2, Sb/Nbmixed oxide, Sb6O13 and non-stoichiometric rutile-type V/Nb/Sb/O; the latter segregated preferentially at the surface of the catalyst. Tin oxide provided the rutile matrix for the dispersion of the mixed oxides. The main role of Sb was shown to generate mixed oxides containing specific sites for the allylic ammoxidation of propylene intermediately formed. The presence of Nb enhanced the activity and selectivity of these sites

Controlled Growth of WO3Nanostructures with Three Different Morphologies and Their Structural, Optical, and Photodecomposition Studies

Tungsten trioxide (WO3) nanostructures were synthesized by hydrothermal method using sodium tungstate (Na2WO4·2H2O) alone as starting material, and sodium tungstate in presence of ferrous ammonium sulfate [(NH4)2Fe(SO4)2·6H2O] or cobalt chloride (CoCl2·6H2O) as structure-directing agents. Orthorhombic WO3having a rectangular slab-like morphology was obtained when Na2WO4·2H2O was used alone. When ferrous ammonium sulfate and cobalt chloride were added to sodium tungstate, hexagonal WO3nanowire clusters and hexagonal WO3nanorods were obtained, respectively. The crystal structure and orientation of the synthesized products were studied by X-ray diffraction (XRD), micro-Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM), and their chemical composition was analyzed by X-ray photoelectron spectroscopy (XPS). The optical properties of the synthesized products were verified by UV–Vis and photoluminescence studies. A photodegradation study on Procion Red MX 5B was also carried out, showing that the hexagonal WO3nanowire clusters had the highest photodegradation efficiency

A new physical mapping approach refines the sex-determining gene positions on the Silene latifolia Y-chromosome

Sex chromosomes are particularly interesting regions of the genome for both molecular genetics and evolutionary studies; yet, for most species, we lack basic information, such as the gene order along the chromosome. Because they lack recombination, Y-linked genes cannot be mapped genetically, leaving physical mapping as the only option for establishing the extent of synteny and homology with the X chromosome. Here, we developed a novel and general method for deletion mapping of non-recombining regions by solving "the travelling salesman problem", and evaluate its accuracy using simulated datasets. Unlike the existing radiation hybrid approach, this method allows us to combine deletion mutants from different experiments and sources. We applied our method to a set of newly generated deletion mutants in the dioecious plant Silene latifolia and refined the locations of the sex-determining loci on its Y chromosome map

Etude des phases lamellaire D et isotrope L2 du systeme eau/octylbenzene sulfonate de sodium/pentanol par diffusion centrale des rayons X

SIGLET 55296 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

caractérisation de surfaces de catalyseurs en conditions quasi in situ (conférence invitée)

SSCI-VIDE+Equipe-Vide+PDENational audienceNon

Etude critique d'une pratique de mésusage des médicaments (le broyage des comprimés et l'ouverture des capsules)

MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF

Structure of the lamellar and L2 phases in the system sodium n-octylbenzene sulfonate/n-pentanol/water

The structure of the isotropic phase L2 occurring in the ternary system sodium octylbenzene sulfonate/n-pentanol/water is discussed on the basis of small angle X-ray scattering data. Experimental results are consistent with a local lamellar structure with a fraction of the alcohol expelled from the lamellar regions. The correlation length of this structure is about ten times smaller than is found in lamellar liquid crystals.La structure de la phase isotrope L2 apparaissant dans le système octylbenzène sulfonate de sodium/n-pentanol/eau est discutée à partir de résultats obtenus en diffusion centrale des rayons X. Ces résultats sont compatibles avec une structure locale lamellaire où une partie de l'alcool serait rejetée de la structure lamellaire. La longueur de corrélation d'une telle structure est à peu près dix fois plus faible que dans le cristal liquide lamellaire

Etude XPS du dopage de photocatalyseurs TIO2

International @ AIR+PDE:EPU:PAFInternational audienceNon