Low temperature growth and electrical characterization of insulators for GaAs MISFETS

Progress in the low temperature growth of oxides and layers on GaAs and the detailed electrical characterization of these oxides is reported. A plasma anodization system was designed, assembled, and put into operation. A measurement system was assembled for determining capacitance and conductance as a function of gate voltage for frequencies in the range from 1 Hz to 1 MHz. Initial measurements were carried out in Si-SiO2 capacitors in order to test the system and in GaAs MIS capacitors abricated using liquid anodization

Research on gallium arsenide diffused junction solar cells

The feasibility of using bulk GaAs for the fabrication of diffused junction solar cells was determined. The effects of thermal processing of GaAs was studied, and the quality of starting bulk GaAs for this purpose was assessed. These cells are to be made by open tube diffusion techniques, and are to be tested for photovoltaic response under AMO conditions

Diffused P+-N solar cells in bulk GaAs

Recently melt grown GaAs, made by liquid encapsulation techniques, has become available. This material is of sufficiently good quality to allow the fabrication of solar cells by direct diffusion. Results obtained with p(+)/n junction solar cells made by zinc diffusion are described. The quality of bulk GaAs for this application is evaluated

Encapsulated diffusion of sulphur into InP

This talk outlines a simple process for the fabrication of n(+)-p solar cells in indium phosphide. Large area cells (greater than 0.25 sq cm) have been made by this process, with a photovoltaic conversion efficiency of 15.21 percent under AM0 conditions of illumination. An ideality factor of 1.1 and a saturation current density of 8 x 10 to the minus 15th power A/sq cm have been observed for these cells. The technique for cell fabrication involves the diffusion of sulfur into InP by an open tube process, and gives highly reproducible results from run to run. A vacuum-deposited layer of gallium sulphide (Ga2S3) was used as the source for sulfur diffusion, with a chemically vapor deposited SiO2 cap layer to prevent decomposition of the InP surface during heat treatment. Diffusions were carried out in a flowing nitrogen ambient at 585 to 708 C, and characterized by their surface carrier concentration and the diffusion constant. The diffusion profile for sulfur in InP is estimated to be of the complementary error function type. The activation energy of the diffusion was estimated to be 1.94 eV. The technique described here is ideally suited for the fabrication of shallow n(+)-p junctions in InP, and has been used for space-borne solar cells

Solar cells in bulk InP using an open tube diffusion process

A simple open tube diffusion technique for the fabrication of n+p junction solar cells is described. Large area (greater than 0.25 square cm) solar cells have been made by this process with a photovoltaic conversion efficiency of 15.2 percent under simulated AMO illumination. An ideality factor is 1.04 and a saturation current density of 9.6 times 10 to the minus 16th power A/square cm have been observed for these cells. These are the lowest (best) values reported to date for diffused structures in bulk InP

Idiopathic Anaphylaxis

A anafilaxia idiopática, descrita pela primeira vez em 1978, é um diagnóstico de exclusão, sendo definida como uma forma de anafilaxia na qual, após investigação exaustiva, não é possível encontrar uma causa específica. Após o seu reconhecimento, foram descritos novos casos, publicadas várias séries de doentes, sendo actualmente uma entidade bem caracterizada, com um sistema de classificação e com um esquema de tratamento bem definido e eficaz. Apesar de ser potencialmente fatal, está associada a um bom prognóstico na maioria dos doentes. Um diagnóstico atempado, bem como a aplicação dos protocolos terapêuticos recomendados, resulta numa diminuição do número de episódios, do número de hospitalizações e dos custos associados

Motivational determinants of physical education grades and the intention to practice sport in the future

Self-Determination Theory (SDT) is amongst motivational frameworks the most popular and contemporary approach to human motivation, being applied in the last decades in several domains, including sport, exercise and physical education (PE). Additionally, Achievement Goal Theory (AGT) has presented evidence of how contextual factors may influence student's behavior in this particular context. The main purpose of this study was to analyze the motivational climate created by the teacher in the classroom, students' satisfaction of Basic Psychological Needs (BPN), and how their behavioral regulation could explain PE grades and intention to practice sports in the future.Funding: This project was supported by the National Funds through FCT – Portuguese Foundation for Science and Technology (UID/ DTP/04045/2013) – and the European Fund for Regional Development (FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145FEDER-006969) – Competitiveness and Internationalization (POCI).info:eu-repo/semantics/publishedVersio

Extending Qualitative Spatial Theories with Emergent Spatial Concepts: An Automated Reasoning Approach

Qualitative Spatial Reasoning is an exciting research field of the Knowledge Representation and Reasoning paradigm whose application often requires the extension, refinement or combination of existent theories (as well as the associated calculus). This paper addresses the issue of the sound spatial interpretation of formal extensions of such theories; particularly the interpretation of the extension and the desired representational features. The paper shows how to interpret certain kinds of extensions of Region Connection Calculus (RCC) theory. We also show how to rebuild the qualitative calculus of these extensions.Junta de Andalucía TIC-606

Comparative performance of diffused junction indium phosphide solar cells

A comparison is made between indium phosphide solar cells whose p-n junctions were processed by open tube capped diffusion, and closed tube uncapped diffusion, of sulfur into Czochralski grown p-type substrates. Air mass zero, total area, efficiencies ranged from 10 to 14.2 percent, the latter value attributed to cells processed by capped diffusion. The radiation resistance of these latter cells was slightly better, under 1 MeV electron irradiation. However, rather than being process dependent, the difference in radiation resistance could be attributed to the effects of increased base dopant concentration. In agreement with previous results, both cells exhibited radiation resistance superior to that of gallium arsenide. The lowest temperature dependency of maximum power was exhibited by the cells prepared by open tube capped diffusion. Contrary to previous results, no correlation was found between open circuit voltage and the temperature dependency of Pmax. It was concluded that additional process optimization was necessary before concluding that one process was better than another

Viral Respiratory Infections in Children

Introdução: Os vírus respiratórios são uma importante causa de morbilidade e constituem a principal causa de dificuldade respiratória na infância. Os agentes mais frequentes são o vírus sincicial respiratório (VSR) e rínovirus humano (RV). Outras agentes menos comuns incluem os vírus influenza, parainfluenza, adenovírus e os mais recentemente identificados coronavírus, metapneumovírus humano e bocavírus humano. O objectivo foi descrever as infecções por vírus respiratórios numa amostra de crianças internadas. Métodos: Foi feita uma revisão dos pedidos de pesquisa de vírus respiratório em crianças abaixo dos 5 anos, internadas por infecção respiratória entre 1 de Outubro de 2010 e 15 de Fevereiro de 2012 e dos respectivos processos clínicos. Resultados: Foi realizada pesquisa de vírus respiratórios por imunoflorescência directa em 664 crianças, com resultados positivos em 268 (40.4%): VSR (n=240, 89.6%), metapneumovírus (n=10), influenza A (n=7), parainfluenza (n=6), adenovírus (n=2) e 3 casos de co-infecção. O maior número de casos positivos ocorreu entre Dezembro 2010 e Janeiro 2011 (n=263, 39.6% do total de casos positivos) e Dezembro 2011 e Janeiro 2012 (n=183, 27.6% do total de casos positivos). A maioria das crianças apresentava infecções adquiridas na comunidade (n=605, 91.1%), com dificuldade respiratória em 422 casos (69.8%). Os restantes casos correspondiam a infecções nosocomiais (n=59, 8.9%). A infecção por VSR foi mais frequente em crianças abaixo dos seis meses (65.2%, p<0.0001) e associou-se de forma estatisticamente significativa a dificuldade respiratória (96.3%, p<0.0001), hipoxémia e corticoterapia sistémica (35.6%, p=0.0001). A maioria das crianças com sibilância recorrente apresentava dificuldade respiratória (91.9%, p<0.0001). Discussão: Nas infecções respiratórias na infância com necessidade de internamento destaca-se a preponderância de infecções por VSR, com padrão sazonal típico (com pico de incidência nos meses de Inverno) e o maior risco de internamento em infecções por VSR abaixo dos 6 meses de idade