Photo-induced transformations in chalcogenide nanocomposite layers

Investigations of photo-induced structural transformations (PST) and related changes of optical parameters in amorphous chalcogenide layers were further developed towards the establishment of their dependence on the compositional modulation of the material at nanoscale-dimensions (similar to3-10 nm) and possible improvement of optical recording parameters as well. Besides the known amorphous-amorphous PST, photo-stimulated interdiffusion and crystallization in multilayer structures were found as a useful method for amplitude-phase optical relief formation. The last two types of PST were influenced by size restrictions and efficiently operated by the composition and by the modulation period of the layered nanocomposite. Experimental evidences were obtained in Se-, AsSe-, Se0.4Te0.6-containing layered or quasi zero-dimensional structures based on As2S3 or SiOx and MgF2 matrix. Comparison was made with As2S3- and GeS2-based multicomponent layers, containing Se, Te and Ga. (C) 2004 Elsevier B.V. All rights reserved.

Photo-induced transformations in chalcogenide composite layers

Investigations of photo-induced structural transformations (PST) and related changes of optical parameters in the light-sensitive amorphous chalcogenides were extended to composite layers, which consist of a wide band-gap material and an active material, Se60Te40 with a smaller band gap. Photo-stimulated interdiffusion and/or crystallization in layered Se0.6Tc0.4/As0.6Se0.94 and Se0.6Te0.4/SiOx were investigated with respect to their dependence on the compositional modulation of the multilayer at scale-dimensions (similar to3-10nm). It was established that PST due to the interdiffusion and crystallization can be efficiently operated by the composition of the adjacent layers of the multilayer which results in the change of the transformation rate and of the optical relief type (positive or negative). The comparison with a single Se0.6Te0.4 layer and with the known data for amorphous-Se/As2S3 multilayers supports the advantages of composite layers for amplitude-phase optical recording. (C) 2004 Published by Elsevier B.V.

Photo-induced effects in Ge25Ga10S65 glasses studied by XPS and XAS

The present paper focuses on the structural, electronic, and compositional properties of Ge25Ga10S65 glasses before and after UV illumination in air using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) techniques. The XPS Ge 3d spectra reveal the existence of Ge-O bonds in the surface region of illuminated glass. In the case of this sample, XAS O K-edge spectra showed the formation of an enriched region of oxygen atoms in the glass bulk, indicating a different bonding structure of oxygen at the surface and in the bulk of the glass. Moreover, the structural changes that occur after UV illumination in the glass sample are identified as the formation of a homogeneous germanium oxide surface layer followed by an intermediary Ge25Ga10S65-yOz subsurface region. (c) 2005 Elsevier B.V. All rights reserved.

Fuzzy environmental quality index

This paper presents the construction of a fuzzy environmental quality index for decision support in municipal environmental management. Five groups of indicators were selected in order to obtain an equation that best represented reality in terms of environmental quality. The calculation was carried out using fuzzy mathematical concepts, with the aid of the package Fuzzy Logical Toolbox 2.1 for Matlab ® 6.1, which provides functions and some applications of the theory of fuzzy sets. The work seeks to create a method of inference concerning the nature of urban areas that are unsustainable with respect to the environment, an issue that is often relegated to the background during public policy discussions. The development of this index, together with its implementation and dissemination, could improve public awareness of environmental issues, and promote mobilization towards the use of best practices in local development. © 2010 IEEE.

Governance crisis and the Andean region: a political economy analysis

Includes bibliography

Comparação dos testes de escada, caminhada e espirometria preditos com os obtidos no pós-operatório de ressecções pulmonares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Processos inferenciais: contribuições das ciências cognitivas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Macroecologia de cetáceos marinhos (ordem cetacea)

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Experiências da precarização e precariedade do trabalho bancário: um enfoque sobre as narrativas de vida e trabalho do antigo e do novo bancário do Bradesco

Pós-graduação em Ciências Sociais - FFC

Acesso ao direito e a democratização da justiça na assistência jurídica integral e gratuita contemporânea

Pós-graduação em Ciências Sociais - FFC

O papel dos municípios na segurança pública: relações entre CONSEG e administração municipal (1985-2008)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Responsabilidade do Estado e do magistrado frente à concessão ou denegação de tutelas de urgência

Pós-graduação em Direito - FCHS

Condutividade elétrica e polarização térmica de vidros soda-cal-sílica contendo diferentes cátions tetravalentes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Variazioni attraverso i secoli, op 71 de Mário Castelnuovo-Tedesco: um estudo sobre a história da forma Tema e Variações no repertório violonístico

Pós-graduação em Música - IA

Polinômios algébricos e trigonométricos com zeros reais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)