Search results for "Roche"
showing 10 items of 2666 documents
Investigation of Activities for Pt-M Bimetallic Nanoparticles Catalysts on the Oxygen Reduction Reaction
2015
Bi-metallic Pt3Ni/C and Pt3Co/C electrocatalysts were successfully synthesized by a solvent free chemical vapour deposition method with a narrow particle size distribution. The results showed that the electrochemical surface area was increased by adding the additional Ni or Co to a pure Pt catalyst. Pt3Ni/C catalyst exhibited a significant enhancement of oxygen reduction reaction activity. The catalysts were characterized by EDS, XRD, HRTEM and electrochemical activity was determined using cyclic voltammetry.
Determination of the Boron/Lead Ratio in Ceramic Materials Based on Electrochemical Quartz Crystal Microbalance
2004
A method for quantitatively determining the relationship boron/lead in ceramic materials is presented. It is based on the attachment of microsamples of ceramic frits to an electrochemical quartz crystal microbalance (EQCM). After a reductive deposition step in the � 0.25 to � 0.85 V (vs. AgCl/Ag) potential range, well-defined stripping peaks are recorded in 0.10 M NaCl plus 0.10 M mannitol. The deposition of boron and lead from suspensions of solid materials, and its subsequent oxidative dissolution can be monitorized at the EQCM. The quotient between the maximum mass gain and the corresponding charge passed enables for a direct quantitation of the boron/lead molar ratio in ceramic material…
Studies of the initial oxidation of cobalt in alkaline solutions using scanning electrochemical microscope
1998
Studies of the initial oxidation of cobalt in alkaline solutions using scanning electrochemical microscope
An unexpected ring carboxylation in the electrocarboxylation of aromatic ketones
2006
The electrocarboxylation of various aromatic ketones, carried out in N-methyl-2-pyrrolidone (NMP) in a diaphragmless cell equipped with a carbon cathode and an aluminium sacrificial anode, yielded, among the products, the target hydroxy acids, the corresponding alcohols and pinacols and, quite surprisingly, detectable amounts of substituted benzoic acids and cycloexene carboxylic acids. These compounds arise from a never reported before electrocarboxylation on the aromatic ring, respectively, for substitution of an aromatic hydrogen and from an addition reaction. For example, the electrocarboxylation of acetophenone gave rise to the substituted benzoic acids in ortho, para and meta position…
Monte Carlo Simulations of Parallel Charged Platelets as an Approach to Tactoid Formation in Clay
2013
The free energy of interaction between parallel charged platelets with divalent counterions has been calculated using Monte Carlo simulations to investigate the electrostatic effects on aggregation. The platelets are primarily intended to represent clay particles. With divalent counterions, the free energy for two platelets or two tactoids (clusters of parallel platelets) shows a minimum at a short separation due to the attraction caused by ion-ion correlations. In a salt-free system, the free energy of interaction has a long-range repulsive tail beyond the minimum. The repulsion increases for tactoids with larger aggregation numbers, whereas the depth of the free-energy minimum is graduall…
ORR Activity and Stability of Co-N/C Catalysts Based on Silicon Carbide Derived Carbon and the Impact of Loading in Acidic Media
2018
This work was supported by the EU through the European Regional Development Fund under projects TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011), NAMUR ”Nanomaterials - research and applications” (3.2.0304.12-0397) and by the Estonian institutional research grant No. IUT20-13.
Les organisations publiques : des institutions communicantes ? Le cas des Caisses d'Allocations Familiales
2009
L’objectif de cet article est de proposer une approche comprehensive de la communication des organisations publiques a travers le cas des Caisses d’Allocations Familiales (CAF). Les travaux dont il est issu ont eu pour objet d’interroger les representations des cadres, charges de communication et directeurs des CAF autour de la notion d’institution communicante. Il s’agit notamment de preciser si celle-ci releve d’un artefact ou pourrait -et a quelles conditions- constituer un modele valide pour analyser la communication des organisations publiques.
De la culture à la communication au sein de l'organisation : Éléments de méthode pour une approche compréhensive des interactions
2009
8 pages; International audience; L'organisation est un univers signifiant, animé par des rites, des mythes et des valeurs. Pendant les années quatre-vingts, le concept de culture organisationnelle a connu un succès fulgurant, suivi, semble-t-il, d'un déclin tout aussi rapide. À la fin de la décennie, certains déclaraient déjà mort, un concept autour duquel il semblait y avoir très peu de consensus (Frost et al., 1991 : 1). Pour mieux mettre en relation les diverses approches des nombreux travaux dans ce domaine, Joanne Martin et Debra Meyerson (Meyerson et Martin, 1987 ; Martin, 1992) distinguent trois perspectives adoptées, par les uns et les autres, à l'égard de la culture organisationnel…
Determination of the atmospheric precipitation pH value on the basis of the analysis of lichen cationoactive layer constitution
2006
Studies of equilibria and kinetics of the ion exchange process between the surrounding (water solution) and lichens prove that the number of mobile hydrogen ions bonded in lichens depends on the concentration of hydrogen ions in the precipitation with which the lichens are in contact and the type and concentration of other cations contained in the precipitation. The measurement of these values was suggested; as a result, it enabled to determine the pH of precipitation by determination of mobile cations bonded in exposed or naturally grown lichens. The studies were conducted on Hypogymnia physodes lichens.
Dendrochronologie : potentialités et nouveaux enjeux pour l’archéologie préventive
2019
International audience; La dendrochronologie, méthode de datation qui étudie la variation des largeurs des cernes de croissance des arbres, est sollicitée, en archéologie, pour l’obtention d’une date absolue. Elle nécessite un dialogue incontournable entre les différents acteurs de la discipline pour fiabiliser les acquisitions, voire tout simplement obtenir une date. L’analyse des bois archéologiques ne se limite toutefois pas à la seule datation et constitue le point de départ de nouvelles approches qui permettent de combler des espaces et des champs de recherche encore lacunaire, pour le sud de la France notamment. Dans le contexte des changements climatiques actuels, la dendrochronologi…