160 research outputs found
Procedimiento conciliatorio en Colombia
La conciliación es uno de los mecanismos alternativos de solución de conflictos más importantes y desarrollados en Colombia. Pese a que las normas legales que rigen la materia son las mismas, en la práctica parece que los conciliadores y centros de conciliación aplican el procedimiento de manera diferente. El presente texto tiene como objetivo poner a disposición de las personas interesadas en la conciliación una descripción de las etapas que integran el procedimiento conciliatorio. El análisis jurÃdico del procedimiento empieza con los requisitos de la solicitud de conciliación y termina con el seguimiento que se debe hacer al resultado del servicio ofrecido. Para el desarrollo de la presente obra, se integra la legislación, la jurisprudencia y los conceptos de lÃnea institucional del Ministerio del Interior y de Justicia con ejemplos sencillos que permiten un mejor entendimiento de los conceptos que se quieren dar a conocer
The effect of compressive strain on the Raman modes of the dry and hydrated BaCe0.8Y0.2O3 proton conductor
The BaCe0.8Y0.2O3-{\delta} proton conductor under hydration and under
compressive strain has been analyzed with high pressure Raman spectroscopy and
high pressure x-ray diffraction. The pressure dependent variation of the Ag and
B2g bending modes from the O-Ce-O unit is suppressed when the proton conductor
is hydrated, affecting directly the proton transfer by locally changing the
electron density of the oxygen ions. Compressive strain causes a hardening of
the Ce-O stretching bond. The activation barrier for proton conductivity is
raised, in line with recent findings using high pressure and high temperature
impedance spectroscopy. The increasing Raman frequency of the B1g and B3g modes
thus implies that the phonons become hardened and increase the vibration energy
in the a-c crystal plane upon compressive strain, whereas phonons are relaxed
in the b-axis, and thus reveal softening of the Ag and B2g modes. Lattice
toughening in the a-c crystal plane raises therefore a higher activation
barrier for proton transfer and thus anisotropic conductivity. The experimental
findings of the interaction of protons with the ceramic host lattice under
external strain may provide a general guideline for yet to develop epitaxial
strained proton conducting thin film systems with high proton mobility and low
activation energy
Raman spectroscopy as a powerful tool to characterize ceria-based catalysts
International audienceA review. CeO2 is widely used and investigated as an oxide catalyst or support due to its unique redox property of oxygen storage and release. In this paper, the different opportunities offered by Raman spectroscopy for advanced characterization of ceria-based catalysts are reviewed: spectral modifications induced by nanocrys-tallinity, defects, doping and reduction, identification of supported molecular species, isolated atoms and nan-oclusters, characterization of surface modes, hydroxyl groups, reaction intermediates such as peroxo and super-oxo species. Finally, in situ/operando studies for environmental catalysis are summarized illustrating Raman spec-troscopy as a powerful tool to characterize ceria-based catalysts
Applications of Raman spectroscopy to heterogeneous catalysis
SSCI-VIDE+ECI2D+SLOInternational audienceSome applications of Raman spectroscopy for the characterization of heterogeneouscatalysts are presented to highlight the power of thistechnique. After a short background, contributions of Raman spectroscopy tomonitor the preparation, the activation of solid catalysts, and to characterizetheir structures are illustrated. It includes chemometric analysis of precursor solutionsused for catalyst preparation, the use of resonance effect to characterizedefects, in situ measurements, and the use of micro-Raman mappings to controlhomogeneity of the micrometer scale
Caractérisation de la surface de perovskites La(1-x)SrxCo(1-y)FeyO3, utilisées dans le traitement des composes organiques volatils.
internationalInternational audienc
Caractérisation de sites d'adsorption de O2 par spectroscopie Raman in situ : différences entre Ce02 et Pt/Ce02
National @ RAFFINAGE+MDA:SLOInternational audienceNon
Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO2 and Pt/CeO2
RAFFINAGE+MDA:SLONon
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