Search results for "ESR"
showing 10 items of 190 documents
Luminescence and photo-thermally stimulated defect creation processes inPbWO4:Mo,La,Y (PWO III) crystals
2015
Photoluminescence, thermally stimulated luminescence and electron spin resonance are studied for a PbWO4 crystal grown by the Czochralski method at Bogoroditsk Technical Chemical Plant, Russia from the melt with a precise tuning of the stoichiometry and co-doped with La3+, Y3+, and Mo6+ ions. Photo-thermally stimulated processes of electron and hole centers creation under selective UV irradiation of the crystal in the 3.5–5.0 eV energy range and 85–205 K temperature range are clarified and the optically created electron and hole centers are identified. The electrons in this crystal are found to be mainly trapped at the (MoO4)2− groups as well as at the (WO4)2– groups located close to single…
El G-8 y las Naciones Unidas
2001
Dos españoles, al frente de 'Le Monde Diplomatique'
2000
Multitechnique Analysis of the Hydration in Three Different Copper Paddle-Wheel Metal-Organic Frameworks
2019
The structural instability in a humid environment of the majority of metal-organic frameworks (MOFs) is a challenging obstacle for their industrial-scale development. Recently, two water-resistant MOFs have been synthetized, STAM-1 and STAM-17-OEt. They both contain copper paddle wheels, like the well-known water-sensitive HKUST-1, but different organic linkers. The crystal lattice of both the MOFs undergoes a phase transition upon interaction with water molecules. Their unusual flexibility allows the controlled breaking of some interpaddle wheel Cu-O interactions in the so-called crumple zones, with a mechanism called hemilability, which is considered to have a crucial role for the stabili…
Sensitivity of alanine dosimeters with gadolinium exposed to 6 MV photons at clinical doses.
2011
In this study we analyzed the ESR signal of alanine dosimeters with gadolinium exposed to 6 MV linear accelerator photons. We observed that the addition of gadolinium brings about an improvement in the sensitivity to photons because of its high atomic number. The experimental data indicated that the addition of gadolinium increases the sensitivity of the alanine to 6 MV photons. This enhancement was better observed at high gadolinium concentrations for which the tissue equivalence is heavily reduced. However, information about the irradiation setup and of the radiation beam features allows one to correct for this difference. Monte Carlo simulations were carried out to obtain information on …
Improvement of the LET sensitivity in ESR dosimetry for -photons and thermal neutrons through gadolinium addition
2007
Abstract We investigated the ESR response of new materials, alanine and ammonium tartrate to which gadolinium was added. The addition of gadolinium enhances sensitivity for Co 60 γ -photons because of its high atomic number ( Z = 64 ) and an enhancement of sensitivity for thermal neutrons because of its high thermal neutron cross section and high linear energy transfer (LET) secondary particles produced after the reaction with neutrons. In particular, in this paper we analyzed the microwave power saturation properties of dosimeters of alanine and ammonium tartrate with or without gadolinium exposed to different LET beams. The power saturation trends of dosimeters exposed to photons and to t…
ELECTRON SPIN RESONANCE AND ELECTROCHEMICAL STUDIES OF OXIDATION PRODUCTS DERIVATES OF APOMORPHINE IN APROTIC SOLVENTS
2002
Apomorphine acts as contractile muscular agent through an extra cellular calcium mechanism dependent. This activity is accompanied with autoxidación process producing o-quinone derivates. o-Quinone is also obtained by apomorphine oxidation in acid medium; in basic conditions a hydroxi-p-quinone is formed. In order to characterize the apomorphine derivates species generated via metabolism or chemical mechanism, specially free radical forms, electrochemical and Electronic Spin Resonance studies were done to o and p-quinones metabolites in presence or absence of Calcium ions. The electrochemical study of these compounds using cyclic voltametric indicated that the reduction mechanism consists o…
La producción de la subjetividad en los tiempos del neoliberalismo: hacia un imaginario con capacidad de transformación social
2003
La hegemonía neoliberal de las últimas décadas ha traído aparejadas inmensas transfor-maciones económicas, políticas y sociales. El relativo equilibrio que se estableció en las sociedades occidentales de posguerra en la dialéctica entre ciudadanía, subjetividad y emancipación social comenzó a transformarse drásticamente a partir de los años ochenta (Santos 2000). La reorganización del sistema capitalista que surge de este periodo se ha concretado socialmente, en el incremento de la vulnerabilidad social y en el crecimiento de las desigualdades sociales, dando lugar a la emergencia de la llamada ‘nueva cuestión social’ (Robert Castel 1977). El territorio de la globalización, nombre que toma …
De Weimar à Bonn: justice, droit et démocratie en Allemagne au XXe siècle
2020
Ce dossier d'HDR retrace dans un premier volume (document de synthèse) un parcours de recherche qui se situe au carrefour de l’histoire juridique, politique et culturelle de l’Allemagne du XXe siècle et qui m’a menée de travaux d’abord centrés sur l’histoire des idées juridiques sous Weimar vers des recherches relevant d’une histoire culturelle de la justice et au-delà de la démocratie ouest-allemande après 1945. L’unité du dossier réside en premier lieu dans ses objets d’étude : l’articulation entre le droit, la justice et leurs acteurs (les juristes) et la réflexion sur la démocratie. Il montre ce qu’une approche historique du droit et de la justice peut apporter à la compréhension de l’h…