Search results for " oxides"
showing 10 items of 166 documents
Ab initio study of tungsten trioxide WO3 in volume and surface area
2012
The structure and stability of different crystallographic phases of tungstentrioxide and the effect of potassium doping have been studied using ab initiocalcuations, both in the bulk and at the surface. The study was motivatedby experimental works on the growth of WO3 nanorods on a mica substrate.The nanorods adopt a hexagonal phase, which is metastable in bulk WO3.The first part of the manuscript reports the study of bulk WO3. For thehexagonal and monoclinique phase, the atomic structure is deterimined andcompared with different models that have been proposed in the experimentalliterature. The relative stability of the two phases is calculated as a functionof potassium doping. From this an…
Heparin–polynitroxide derivatives: a platform for new diagnostic and therapeutic agents in cardiovascular disease?
2013
Vascular wall extracellular oxidative stress Cardiovascular disease (CVD; mainly atherosclerosis, hypertension and diabetes mellitus) remains a major cause of death in western society [1]. Despite substantial progress achieved, the diagnosis of CVD often comes too late, when the disease has already advanced to therapeutically incurable stages. The development of efficient diagnostic probes allowing early non-invasive diagnostics, as well as drugs which can prevent or reverse CVD and/or its complications (e.g., myocardium infarctus and stroke) are highly desired tasks of the modern cardiovascular medicinal chemistry.
NO formation tendency characterization for solid fuels in fluidized beds
2013
Abstract Usually the standard fuel analysis is not enough to allow for accurate NO emission predictions in large scale fluidized bed combustion. This paper presents NO formation tendency characterization results from novel laboratory measurements in a small-scale fluidized bed combustor. With the special two-stage oxidation method it is possible to eliminate the observed problems of unstable test conditions during rapid pyrolysis of high-volatile fuels in batch combustion. Experimental results of the conversion of fuel nitrogen to NO are presented for wide range of fuels, ranging from coal-type fuels to peat, biomasses and wastes. A NO formation tendency database is formed based on the resu…
Les matériaux pour capteurs chimiques
2002
National audience; A chemical sensor is composed of one part supplying chemical reco gnition coupled to one transducingsystem. At the recognition origin, interaction with the target chemical species is oftwo types, either electronicexchange, or ionic exchange. Two large classes of materials that can supply recognition proceed: metals andsemiconductors giving rise to electronic exchange and ionic conducting materials giving rise to ionic exchan-ge. This paper is structured in tw o large parts, emphasizing on materi als inducing specific interactions:semiconductor materials (metallic oxides and molecular semiconductors) and ionic conductor materials.In each part will be presented nature of ma…
α-Aminophosphonates, Phosphinates, and Phosphine Oxides as Extraction and Precipitation Agents for Rare Earth Metals, Thorium, and Uranium : A Review
2022
α-Aminophosphonates, -phosphinates, and -phosphine oxides are a group of organophosphorus compounds that were investigated as extraction agents for rare earth (RE) metals and actinoids for the first time in the 1960s. However, more systematic investigations of their extraction properties towards REs and actinoids were not started until the 2010s. Indeed, recent studies have shown that these α-amino-functionalized compounds can outperform the commercial organophosphorus extraction agents in RE separations. They have also proven to be very efficient extraction and precipitation agents for recovering Th and U from RE concentrates. These actinoids coexist with REs in some of the commercially im…
Ibuprofen degradation using a Co-doped carbon matrix derived from peat as a peroxymonosulphate activator
2021
The wider presence of pharmaceuticals and personal care products in nature is a major cause for concern in society. Among pharmaceuticals, the anti-inflammatory drug ibuprofen has commonly been found in aquatic and soil environments. We produced a Co-doped carbon matrix (Co-P 850) through the carbonization of Co2+ saturated peat and used it as a peroxymonosulphate activator to aid ibuprofen degradation. The properties of Co-P 850 were analysed using field emission scanning electron microscopy, energy filtered transmission electron microscopy and X-ray photoelectron spectroscopy. The characterization results showed that Co/Fe oxides were generated and tightly embedded into the carbon matrix …
Effect of ammonium hydroxide addition in the anodizing electrolyte on the electronic properties of anodic oxides on Niobium
2010
Thermodynamics of Aqueous Poly(ethylene oxide)−Poly(propylene oxide)−Poly(ethylene oxide)/Surfactant Mixtures. Effect of the Copolymer Molecular Weig…
2004
A calorimetric study was performed to focus attention on the interactions between copolymers and anionic surfactants in aqueous solutions. Three aspects were analyzed: (1) the hydrophobicity of the surfactant, (2) the change of the copolymer molecular weight, and (3) the nature of the hydrophilicity of the copolymer. To this purpose, the family of sodium alkanoates (sodium octanoate through sodium dodecanoate) and the triblock copolymers EO76PO 29EO76 (F68), EO103PO39EO 103 and EO132PO50EO132 were investigated. Comparing F68 and EO13PO30EO13 (L64), previously studied by us, provided information on the effect of the copolymer hydrophilicity. The experimental data were analyzed by means of a …
Applications and stereoselective syntheses of P-chirogenic phosphorus compounds.
2016
International audience; Phosphorus compounds bearing chirality on the P-center are usually qualified as P-chirogenic or P-stereogenic. This chemical class concerns natural products, agrochemistry, molecular materials, biology and pharmacy, although it is certainly in coordination chemistry and in asymmetric catalysis using chiral transition metal complexes that P-chirogenic phosphorus compounds are the most used. The chiral phosphine ligands and their uses in asymmetric metal-catalyzed reactions have been widely reviewed in literature. However, an overview covering the applications as well as the stereoselective syntheses of all classes of phosphorus compounds has not yet been provided. Thi…
Emergent ultrafast phenomena in correlated oxides and heterostructures
2017
The possibility of investigating the dynamics of solids on timescales faster than the thermalization of the internal degrees of freedom has disclosed novel non-equilibrium phenomena that have no counterpart at equilibrium. Transition metal oxides (TMOs) provide an interesting playground in which the correlations among the charges in the metal $d$-orbitals give rise to a wealth of intriguing electronic and thermodynamic properties involving the spin, charge, lattice and orbital orders. Furthermore, the physical properties of TMOs can be engineered at the atomic level, thus providing the platform to investigate the transport phenomena on timescales of the order of the intrinsic decoherence ti…