RESUMEN
The paper presents the first results of an investigation on optical absorption (OA), thermally and infrared stimulated luminescence (TL and IRSL) of the Pinacate plagioclase (labradorite). The OA spectra reveal two bands with maxima at 1.0 and 3.2 eV connected with absorption of the Fe3+ and Fe2+ and IR absorption at wavelengths longer than 2700 nm. The ultraviolet absorption varies exponentially with the photon energy following the 'vitreous' empirical Urbach rule indicating exponential distribution of localised states in the forbidden band. The natural TL is peaked at 700 K. Laboratory beta irradiation creates a very broad TL peak with maximum at 430 K. The change of the 430 K TL peak shape under the thermal cleaning procedure and dark storage after irradiation reveals a monotonous increasing of the activation energy that can be explained by the exponential distribution of traps. The IRSL response is weak and exhibits a typical decay behaviour.
Asunto(s)
Silicatos de Aluminio/química , Silicatos de Aluminio/efectos de la radiación , Modelos Químicos , Dosimetría Termoluminiscente/instrumentación , Dosimetría Termoluminiscente/métodos , Álcalis/química , Álcalis/efectos de la radiación , Simulación por Computador , Relación Dosis-Respuesta en la Radiación , Diseño de Equipo , Análisis de Falla de Equipo , Luz , Ensayo de Materiales , México , Fósforo/química , Fósforo/efectos de la radiación , Dosis de Radiación , Erupciones Volcánicas/análisisRESUMEN
Since 1990 forty-one cardiomyoplasty procedures (CMP) were performed in 35 patients with ischemic and in 6 patients with dilated cardiomyopathy. All surviving patients (n=33) revealed decreased functional NYHA class from III to I-II, increased ejection fraction (EF) by a mean of 10 por cento. Results of roentgencontrast ventriculocoronarography (n-8), of radioisotope (n=28) and morphologic (n=9) studies demonstrated the presence of indirect revascularization (IR) of myocardium from the arteries of e transplanted latissimus dorsi muscle (LDM). Thus effective CMP in patients with severe heart failure is firstly a result of myocardial IR development and secondly of LDM functioning as a biomechanical assist device.