Thin films of low density polyethylene (LDPE) and crosslinked polyethylene (XLPE) were aged under an AC electric field while kept in sodium chloride aqueous solution. After aging the samples showed water trees (localized damaged with the appearance of hydrophilic ramified structures whose size ranges from a few microns to I mm). Some of the samples suffered dielectric breakdown showing small channels (1-2 mm. diameter) crossing the film and sometimes also signs of carbonization. In order to identify the oxidation mechanisms contributing to aging, FTIR was used to analyze both unaged and aged specimens. Comparing between unaged and aged LDPE an increase in the FTIR spectrum for bands at 1720 cm(-1), 1640 cm(-1) and 1590 cm(-1) was visible for the aged samples. The first region corresponds to carbonyl groups (C=O bonds) resulting from oxidation (most probably ketones). While the second one is related to carbon double bonds formed due to chain scission. Finally the third one is due to carboxylates. For the XLPE the analysis is more difficult. Besides aging it needs to be taken into account the by-products of crosslinking that will tend also to diffuse out with time. The main effect of aging is an increase in the concentration of 1640 cm(-1) band (C=C bonds). For the water treed regions dry and wet samples were compared. In the wet ones the absorbance is larger for the 3380 cm(-1) exhibiting, as expected, water absorption in the water treed regions (hydrophilic characteristics were increased).

The effect of annealing treatment (in the presence of different types of atmospheres) on the performances of zinc oxide thin films (intrinsic and doped with In and Al) prepared by spray pyrolysis have been studied, with the aim to determine more adequate conditions to improve the properties of the films. The results show that the annealing treatment leads to substantial changes in the structural, electrical and optical characteristics of ZnO thin films. The most significant improvements were obtained after annealing in forming gas (reduction atmosphere) at 200°C during 2 h. The ZnO:In film after heat treatment was the one that exhibited the lowest resistivity (p=5.2x10-2 ωcm) and a high transmittance (T=86%). © 2001 Elsevier Science Ltd. All rights reserved.

In this work we present preliminary results on the sensitivity to methane gas of zinc oxide thin films deposited by spray pyrolysis. It was found that using highly resistive (above 104 Ω cm) thin films and by performing the measurements at 200°C a sensitivity better than one order of magnitude was found to detect 2000 ppm of methane. A linear dependence on the sensitivity between 100 and 2000 ppm of methane was also obtained. © 2001 Elsevier Science Ltd. All rights reserved.

{In this work we report how it is possible to control the plasma regime near the substrate surface, from predominantly α to predominantly γ', passing trough and intermediate α-γ' regime, and simultaneously control the energy of the ions striking the substrate during a-Si:H deposition from a silane glow discharge in a modified triode type PECVD reactor. To do so, we apply a DC voltage (Vpol to a set of grids placed in front of the r.f. electrode and by doing this, we control the energy of the ions striking the substrate during the film's growth and the plasma regime near the substrate. Under a plasma of the γ' regime, the surface roughness is high and the films are poorly compact. In the α-γ' regime, the ion bombardment is moderate and the films are highly smooth and compact. In the α regime the ion bombardment is higher and so the films can become more compact but the surface roughness increases and the electrical properties deteriorate. The results achieved show that the best transport properties are achieved for the films deposited in the α-γ' regime corresponding to a Vpol of 38 V. Under this condition the films presented a dark conductivity, σd = 6.2×10-12 (Ωcm)-1, activation energy, ΔE ≈ 0.9 eV, hydrogen content

In this work a study of the influence of the annealing treatment (atmosphere and temperature) on the properties of zinc oxide thin films (intrinsic and doped with indium and aluminum) prepared by spray pyrolysis is presented. The result shows that the type of atmosphere (reduction or oxidant) has an important role in the changes observed in the structural, electrical and optical properties of the ZnO thin films. The ZnO thin film doped with indium, presents the lowest resistivity (ρ = 5.8×10-3 Ωcm) associated to a high transmittance (T = 86%), characteristics required for application on optoelectronic devices.

This paper presents results of the role of the oxygen concentration (CO) and the deposition pressure (pd) on structural and electrical properties of indium tin oxide films produced by r.f. magnetron sputtering. The films were annealed in air, followed by a reannealed stage in hydrogen, aiming to improve the film's transparency and conductivity. The results achieved show that the films texture grain size, structure and compactness is more influenced by CO than by pd, the same does not happen with the electrical properties.

The choice over the Portuguese case studies was based on the sample constructed for the application of the firm questionnaires, during the second year of the SOWING project, 1999. This sample was fulfilled of firms among several activity sectors: textile, manufacturing, electronics, transports and software industry, based on NACE – codes (2 – digit level). Thus, we agreed to include in a new database the remaining questionnaires and construct a sample with 113 observations. Concerning the organisational change we make a distinction of three categories of change. First we analyse changes taking place at the inter-firm level (outsourcing, subcontracting, geographic relocation), followed by changes at the organisational level (deconcentration/decentralisation, reduction of hierarchical levels, introduction of cost and profit centres). The third kind of changes analysed will be those taking place at the workplace level (job enlargement/enrichment, changing character of work, work load). The Portuguese studied companies presents a relative uniform pattern considering the variables social competencies, practical knowledge, responsibility and specialized professional qualifications.

We examine the most important processes leading to the creation of excited states from the ground configurations of Ar8+ to Ar16+ ions in an electron-cyclotron resonance ion source, which lead to the emission of K x-ray lines. Theoretical values for inner-shell excitation and ionization cross sections, including double KL ionization, transition probabilities and energies for the de-excitation processes, are calculated in the framework of the multi-configuration Dirac-Fock method. With reasonable assumptions about the electron energy distribution, a theoretical K x-ray spectrum is obtained, which reproduces very closely a recent experimental result.

Measurements of electron impact ionization of neutral Al, Ga, and In show large cross sections compared to other elements in the same rows of the periodic table. Semiempirical and classical calculations of direct ionization cross sections are all substantially smaller. Calculations by McGuire [Phys. Rev. A 26, 125 (1982)] for aluminum that include excitations to autoionizing 3s3p2 doublet levels are 2.5 times higher than experiment at the peak. We report the direct ionization cross sections based on the binary-encounter-Bethe model of Kim and Rudd [Phys. Rev. A 50, 3954 (1994)], which is an ab initio theory. We add the autoionization contribution using scaled plane-wave Born cross sections as recently developed by Kim [Phys. Rev. A 64, 032713 (2001)] for excitations to the first set of autoionizing levels. Dirac-Fock wave functions are used for the atomic structure. Our results are in excellent agreement with experimental values and support substantial contributions from excitation-autoionization to the total ionization cross sections for these elements. We also compare the total ionization cross section of boron to available theories, though no experimental data are available.

The increasing degree of inter-dependency and integration of economy at a global scale motivated the globalization of scientific and technological knowledge from manufacturing, to the marketing and the strategic management of companies that act as protagonists of these processes. Globalization of markets is inter-connected with intensive incorporation of knowledge in economy. In this sense the continuous evolution of the manufacturing industry structure for an increased high intensity technology elements, namely information and communication technologies, implies that these industrial sub-sectors are conditioning the global performance of economy, the productivity gains and as a consequence the levels of economical and employment growth. This study on “R&D, Innovation and Employment Creation” for the Portuguese Observatory of Employment and Vocational Training (IEFP-MQE) is updating information on the articulation between Job creation, innovation, technology, and R&D. A diagnosis of the state of national S&T research and of processes of technological and organizational innovation was made, as well of the interfacing structures between the knowledge sector and the economical activities. Were made 12 case studies at companies with some innovation activities, interviews to unionists and to Professional associations, and public offices. Was made also a survey to a selected sample of technological infrastructures.

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This paper deals with a new design method for the interfaces of a-Si:H pin solar cells that improves the stability and performances of devices deposited in a single batch chamber process. The method consists in removing a deposited sacrificial layer placed between the p/i and/or i/n interfaces by etching. This layer is an absorber of defects and impurities that are introduced in the interfaces, mainly from the chamber walls cross-contamination and the substrate surface. The results achieved increase the device fill factor and short circuit current density, respectively towards 75% and 16.3 mA cm-2, with a final efficiency of about 10%, before light soaking experiments. © 2000 Elsevier Science B.V. All rights reserved.

Science and technology (S&T) are considered to be a central source, or at least a basic medium, of societal and industrial innovation, while innovation is conceived to basically feed the regeneration of our welfare. The suppliers of S&T in Europe as well as the users of their „products“, are confronted with a number of challenges today. We want to stress here that it was not the primary goal of our Advanced Science & Technology Policy Planning (ASTPP) Network to come up with proposals how the strategic character of European S&T policies could be strengthened. The ASTPP-network instead focuses on one aspect: the provision of strategic intelligence necessary to identify and develop strategic choices. The underlying hypothesis is that the existing body of experiences with technology foresight, technology assessment and S/T policy evaluation provides a basis for the development of an advanced S&T policy „planning“ approach by trying to enhance, interlink or even integrate the growing, but still dispersed experience in these three areas of intelligence. By „intelligent“ we mean that the inter-relatedness of S&T, industrial efforts, societal needs and political interventions becomes more transparent so that interactive collaboration between them will be facilitated.