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Wide band gap microcrystalline silicon films have aroused considerable interest since they combine some electro-optical advantages of amorphous and crystalline materials highly important to produce electro-optical devices such as TFTs and solar cells. In this paper we present results concerning the electro-optical characteristics of highly transparent and conductive n-type μc-Si based films. Here, emphasis is given to the production of n-type μc-films with optical gaps of 2.3 eV and dark conductivity's of 6.5 Scm-1.

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In this work, we present a model to interpret the steady-state and the dynamic detection limits of 1-D Thin Film Position Sensitive Detectors (1-D TFPSD) based on p-i-n a-Si:H devices. From this, an equivalent electric circuit is derived and the predicted values are compared with the experimental results obtained in 1-D TFPSD devices, with different sizes. The model is also able to determine the device characteristics that influence the spatial limits and the response time of the device. © 1996 IEEE.

The objective of this work is to provide a basis for the interpretation of the a-Si:H photodiode behaviour under low illumination level conditions, where a lateral leakage current plays an important role on the devices' performances when the doped collecting layer can not be considered a true equipotential. To determine this effect, a-Si:H p.i.n devices with small metal dot contacts, matrix distributed, were produced and analysed before and after etching the surrounding doped region of the metal collecting contact. The experimental data fit a model that includes the contribution of a lateral leakage current influencing the J-V characteristics, responsivity and the apparent light degradation behaviour of the device.

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Results are presented which are geared towards an understanding of the influence of powder formation during film growth. Plasma chemistry is correlated with the morphology, structure (inferred through infrared spectroscopy, scanning electron microscopy and X-ray diffraction) electro-optical and density of states of intrinsic films deposited under continuous and power modulated operation. Results show that for modulation frequencies where no powder formation occurs and low substrate temperatures T (150°C), silane decomposition gives rise to the growth of inhomogeneous films while in the high modulation frequency regime, at the same temperature, the anions and powder are trapped resulting in films with high deposition rates and low defect density.

There is an increasing importance of different productive architectures related to worker involvement in the decision making, where is given due attention to the intuitive capabilities and the human knowledge in the optimization and flexibilization of manufacturing processes. Thus having reference point architecture of a flexible manufacturing and assembling system existent at UNINOVA-CRI, we will present some exploratory hypothesis about applicability of the concept of hybridization and its repercussions on the definition of jobs, in those organizations and in the formation of working teams.

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The aim of this work is to present a model to interpret the static and the dynamic detection and resolution limits of 1D thin film position sensitive detectors based on p-i-n a-Si:H devices. The model can determine the device characteristics that influence the spatial limits and the response time of the device.

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This paper presents results of the role of the oxygen partial pressure used during the deposition process on the transport properties exhibited by doped microcrystalline silicon oxycarbide films produced by a Two Consecutive Decomposition and Deposition Chamber system, where a spatial separation between the plasma and the growth regions is achieved. This paper also presents the interpretative models of the optoelectronic behaviour observed in these films (highly conductive and transparent with suitable properties for optoelectronic applications) as well as the interpretation of the growth process that leads to film's microcrystallization.

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The primary structure of desulfoferrodoxin from Desulfovibrio desulfuricans ATCC 27774, a redox protein with two mononuclear iron sites, was determined by automatic Edman degradation and mass spectrometry of the composing peptides. It contains 125 amino acid residues of which five are cysteines. The first four, Cys-9, Cys-12, Cys-28 and Cys-29, are responsible for the binding of Center I which has a distorted tetrahedral sulfur coordination similar to that found in desulforedoxin from D. gigas. The remaining Cys-115 is proposed to be involved in the coordination of Center II, which is probably octahedrally coordinated with predominantly nitrogen/oxygen containing ligands as previously suggested by Mossbauer and Raman spectroscopy.

SPROUT is a computer program for the rational design of molecules for a range of applications in molecular recognition. Molecular graphs are built in a stepwise fashion by subgraph addition. Several heuristics are being explored to restrict the combinatorial explosion that is inherent in structure generation. These include the use of generalized molecular fragments, called templates, as building blocks. Structure generation consists of two stages: (i) the generation of skeletons from templates that satisfy steric constraints and (ii) the substitution of heteroatoms into skeletons to produce molecules that satisfy other constraints such as electrostatics. The choice and definition of the templates and template joining rules are described together with a description of the atom substitution process.

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Owing to the existing or predictable water deficiencies in the South of Portugal, it is necessary to carry out the appropriate management of water resources, by reducing and/or minimizing the negative impacts of untreated/treated domestic effluents in the aquatic environment. As Portugal has a great diversity of ecoclimatic areas, five different stabilization pond systems were chosen to carry out a control study during one year (from March 1991 to March 1992). According to Pina Manique & Albuquerque the ecological classification of these stations is different, varying from Ibero-mediterranean (continental) up to mediterranean (maritime). The physical and chemical parameters studied were: temperature, pH, dissolved oxygen, conductivity, BOD, COD, nitrates, nitrites, ammonia and total nitrogen, total suspended and volatile solids, total phosphorus and orthophosphates. The microbiological parameters studied were: total and faecal coliforms, faecal Streptococci, Clostridium perfringens and Pseudomonas aeruginosa. The correlations between climatic parameters and the efficiency of the removal of organic matter were analysed.

The analytical values obtained from five WSP systems located in different ecoclimatic zones in the centre and South of Portugal, were subjected to a statistical analysis of K and K20 values (as used in the van Hoff-Arrhenius equation) utilizing an analysis of variance and a vectorial analysis of principal components. Significant differences between K and K20 values in facultative, maturation ponds and in the whole system were verified. The projection of the first principal components of eigenvectors made possible the classification of the stations, showing the existence of similarities and discrepancies in their removal BOD kinetics behaviour. The K20 value must be estimated and taken into account for the design of waste stabilization ponds.

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