973 resultados para 337.225


Relevância:

10.00% 10.00%

Publicador:

Resumo:

ZnO/MgF2/ZnO sandwich structure films were fabricated. The effects of a buffer layer on structure and optical properties of ZnO films were investigated by X-ray diffraction, photoluminescence, optical transmittance and absorption measurements. Measurement results showed that the buffer layer had the effects of improving the quality of ZnO films and releasing the residual stresses in the films. The near-band edge emissions of ZnO films deposited on the MgF2 buffer layer were significantly enhanced compared with those deposited on bare substrate due to the smaller lattice mismatch between MgF2 and ZnO than that between fused silica and ZnO. (c) 2006 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[ES] La secuencia estratigráfica de un yacimiento arqueológico responde a dos variables relacionables, aportaciones naturales y actividades antrópicas: la conjunción de analíticas propias de la arqueología y la geología permite descifrar los caracteres de dicha sedimentación y reconocer su origen. Se han aplicado exámenes sedimentológicos y químicos a los yacimientos de Atxoste y Los Husos: por sus tipologías son representativos de la dinámica cultural habida a lo largo del Holoceno y sirven en la comprensión de la formación de yacimientos arqueológicos. Ligeros elementos constructivos y la distribución de los items arqueológicos han permitido, además, delomitar una cabaña adosada al abrigo en Atxoste y los cierres de un corral en el covacho de Los Husos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Fentanyl is widely used off-label in NICU. Our aim was to investigate its cerebral, cardiovascular and pulmonary effects as well as pharmacokinetics in an experimental model for neonates. Methods: Fentanyl (5 mu g/kg bolus immediately followed by a 90 minute infusion of 3 mu g/kg/h) was administered to six mechanically ventilated newborn piglets. Cardiovascular, ventilation, pulmonary and oxygenation indexes as well as brain activity were monitored from T = 0 up to the end of experiments (T = 225-300 min). Also plasma samples for quantification of fentanyl were drawn. Results: A "reliable degree of sedation" was observed up to T = 210-240 min, consistent with the selected dosing regimen and the observed fentanyl plasma levels. Unlike cardiovascular parameters, which were unmodified except for an increasing trend in heart rate, some of the ventilation and oxygenation indexes as well as brain activity were significantly altered. The pulmonary and brain effects of fentanyl were mostly recovered from T = 210 min to the end of experiment. Conclusion: The newborn piglet was shown to be a suitable experimental model for studying fentanyl disposition as well as respiratory and cardiovascular effects in human neonates. Therefore, it could be extremely useful for further investigating the drug behaviour under pathophysiological conditions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[ES] En este artículo presentamos nuestra tercera aportación de novedades de la epigrafía de época romana de la provincia de Segovia, con seis piezas nuevas, recogemos dos ya publicadas, de una aportamos nueva lectura e interpretación, e introducimos un apartado de corrigenda con dos entradas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

用电子束蒸发方法在BK7基底上沉积了HfO2/SiO2多层膜。研究了200℃到400℃的退火对残余应力的影响。结果表明退火前的薄膜残余应力为压应力,在200℃退火后发展为张应力,然后张应力值随着退火温度的升高而增大。在400℃退火后,由于张应力太大,薄膜表面出现了裂纹。同时,随着退火温度的升高,晶粒尺寸长大,晶面间距降低。残余应力的变化与结构的演变相对应。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

225 p.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[ES] Este trabajo muestra ejemplos de la difusión que, como modelo, ha tenido el "corpus Tibullianum" en la poesía de Occidente. Ponemos de relieve su apreciación en Inglaterra, donde hemos encontrado un interesante grupo tanto de imitaciones expresas y como de composiciones de diverso signo que se aproximan a la elegía latina a través de Tibulo. La mayor parte de estos testimonios se sitúan en los siglos XVlI y XVIII, coincidiendo con las primeras traducciones inglesas, y terminan con los poetas románticos, que como Byron ya adelantan la actitud de nuestro tiempo ante el "corpus Tibullianum", entre un cierto olvido y admiración.