This paper reports on the thermal and optical properties of germanate glasses GeO 2-PbO co-doped with silver nanoparticles and rare earth ions (Tm 3+ , Er 3+ and Yb 3+) with a focus on the thermal diffusivity (D). The presence of rare earth ions and nanoparticles is evidenced by absorption spectra and TEM images, respectively. Additionally, a structural comparison between thin films and bulk glass with the same nominal composition is given. It is found that D increases up to 20% in samples where nanoparticles are present, although their quantity corresponds only to a volume fraction of 1.7%. Therefore, such enhancement could be associated with the nanoparticles. Nevertheless, a Raman analysis revealed a structural change after the thermal treatment used for the nucleation of the nanoparticles. A decrease in the intensity of the band at 534 cm À1 in the Raman spectra is interpreted as the disruption of the 3-membered rings of the GeO 4 tetrahedra. The Raman analysis also revealed the formation of small crystals of a-GeO 2 type quartz and the adsorption of carbon dioxide on the surface of the silver nanoparticles inserted in the germanate thin film. 2016 Elsevier B.V. All rights reserved.
Mostramos neste trabalho que o erro das medidas associadas a obtenção da gravidade local com o aplicativo Phyphox não são relevantes para atividades didáticas em comparação com métodos tradicionais. Foi realizada a filmagem do experimento do pêndulo simples em que o celular é usado como corpo de prova, ao mesmo tempo que coleta medidas. Obtivemos o valor do período de oscilação de duas formas independentes. Além da própria medida do aplicativo em tempo real, ele foi extraído a partir da análise deste vídeo no programa Tracker. Realizamos também um segundo experimento para comparar os resultados obtidos diretamente de um cronômetro, com aqueles que são extraídos a partir da análise do vídeo, em uma montagem sem o celular. Este caso deixa claro que a influência do operador torna esse método mais impreciso que os outros dois. Ainda é possível observar um efeito inesperado na oscilação durante aproximadamente 24% do tempo para alguns casos, o que torna a modelagem matemática do pêndulo simples não condizente com todos os dados tratados no nosso experimento.
In X-ray macromolecular crystallography (MX), single-wavelength anomalous dispersion (SAD) and multi-wavelength anomalous dispersion (MAD) techniques are commonly used for obtaining experimental phases. For an MX synchrotron beamline to support SAD and MAD techniques it is a prerequisite to have a reliable, fast and well automated energy scan routine. This work reports on a continuous energy scan procedure newly implemented at the BioMAX MX beamline at MAX IV Laboratory. The continuous energy scan is fully automated, capable of measuring accurate fluorescence counts over the absorption edge of interest while minimizing the sample exposure to X-rays, and is about a factor of five faster compared with a conventional step scan previously operational at BioMAX. The implementation of the continuous energy scan facilitates the prompt access to the anomalous scattering data, required for the SAD and MAD experiments.
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