Y học tân thanh. ["puis" Tuần báo phổ thông khoa thuốc]

1938/10/31.

Y học tân thanh. ["puis" Tuần báo phổ thông khoa thuốc]

1938/12/31.

Y học tân thanh. ["puis" Tuần báo phổ thông khoa thuốc]

1939/01/07.

Y học tân thanh. ["puis" Tuần báo phổ thông khoa thuốc]

1939/06/15.

[Dick] Landon, gagnant du saut [en hauteur, porté par Harold Muller et Bo Ekelund, Jeux olympiques d'Anvers, 17/8/20] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 60592

闢妄條駁合刻Pi wang tiao bo he ke.Le Pi wang et le Tiao bo.

Contient : I闢釋氏諸妄Pi shi shi zhu wang ; II闢畧說條駁Pi lüe shuo tiao bai

Escola de natura de la Vall de Bo??. 'Escuela de naturaleza del Valle de Bo??'

En la realizaci??n del v??deo colaboran l'Ajuntament de Barruera (Lleida) y ENHER

Camp d'Aprenentatge de la Vall de Boí. 'Campo de Aprendizaje del Valle de Boí'.

Los campos de aprendizaje son servicios educativos que ofrecen a los chicos y chicas la posibilidad de estar en un entorno singular en Cataluña. Se facilita el contacto con ecosistemas poco alterados por el ser humano. Posibilitan que el material de origen natural que se utiliza en las actividades sea recogido por los alumnos.

Tecnoloxías da información e a comunicación (TIC) : bo uso, mal uso e abuso : riscos e beneficios para a saúde biopsicosocial. 'Tecnologías de la información y comunicación (TIC) : buen uso, mal uso y abuso : riesgos y beneficios para la salud biopsicosocial'.

Resumen basado en el de la publicación

Elaboration and optimization of (Y,Er)Al(3)(BO(3))(4) glassy planar waveguides through the sol-gel process

In this work, a sol-gel route was used to prepare Y(0.9)Er(0.1)Al(3)(BO(3))(4) glassy thin films by spin-coating technique looking for the preparation and optimization of planar waveguides for integrated optics. The films were deposited on silica and silicon substrates using stable sols synthesized by the sol-gel process. Deposits with thicknesses ranging between 520 and 720 nm were prepared by a multi-layer process involving heat treatments at different temperatures from glass transition to the film crystallization and using heating rates of 2 degrees C/min. The structural characterization of the layers was performed by using grazing incidence X-ray diffraction and Raman spectroscopy as a function of the heat treatment. Microstructural evolution in terms of annealing temperatures was followed by high resolution scanning electron microscopy and atomic force microscopy. Optical transmission spectra were used to determine the refractive index and the film thicknesses through the envelope method. The optical and guiding properties of the films were studied by m-line spectroscopy. The best films were monomode with 620 nm thickness and a refractive index around 1.664 at 980 nm wavelength. They showed good waveguiding properties with high light-coupling efficiency and low propagation loss at 632.8 and 1550 nm of about 0.88 dB/cm. (C) 2009 Elsevier B.V. All rights reserved.

Er:YAl(3)(BO(3))(4) glassy thin films from polymeric precursor and sol-gel methods: Waveguides for integrated optics

This paper presents the characterization of single-mode waveguides for 980 and 1550 nm wavelengths. High quality planar waveguide structure was fabricated from Y(1-x)Er(x)Al(3)(BO(3))(4) multilayer thin films with x = 0.02, 0.05, 0.1, 0.3, and 0.5, prepared through the polymeric precursor and sol-gel methods using spin-coating. The propagation losses of the planar waveguides varying from 0.63 to 0.88 dB/cm were measured at 632.8 and 1550 nm. The photoluminescence spectra and radiative lifetimes of the Er(3+) (4)I(13/2) energy level were measured in waveguiding geometry. For most samples the photoluminescence decay was single exponential with lifetimes in between 640 mu s and 200 mu s, depending on the erbium concentration and synthesis method. These results indicate that Er doped YAl(3)(BO(3))(4) compounds are promising for low loss waveguides. (C) 2009 Elsevier B.V. All fights reserved.