We have characterized the structure and electrical properties of p-type nanocrystalline silicon films prepared by radio-frequency plasma-enhanced chemical vapor deposition and explored optimization methods of such layers for potential applications in thin-film solar cells. Particular attention was paid to the characterization of very thin (∼20nm) films. The cross-sectional morphology of the layers was studied by fitting the ellipsometry spectra using a multilayer model. The results suggest that the crystallization process in a high-pressure growth regime is mostly realized through a subsurface mechanism in the absence of the incubation layer at the substrate-film interface. Hydrogen plasma treatment of a 22-nm-thick film improved its electrical properties (conductivity increased more than ten times) owing to hydrogen insertion and Si structure rearrangements throughout the entire thickness of the film. © 2012 National Institute for Materials Science.

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Domain Specific Languages (DSLs) are claimed to increase productivity, while reducing the required maintenance and programming expertise. In this context, DSL usability by domain experts is a key factor for its successful adoption. Evidence that support those improvement claims is mostly anecdotal. Our systematic literature review showed that a usability evaluation was often skipped, relaxed, or at least omitted from papers reporting the development of DSLs. The few exceptions mostly take place at the end of the development process where fixing problems identified is too expensive. We argue that a systematic approach based on User Interface experimental validation techniques should be used to assess the impact of the new DSLs. The rationale is that assessing important and specially tailored usability attributes for DSLs early in language construction will ultimately foster a higher productivity of the DSL users. This paper, besides discussing the quality criteria, proposes a development and evaluation process that can be used to achieve usable DSLs in a better way.

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The energy resource management is a major concern worldwide. Energy management activities minimize environmental impacts of the energy production. Therefore, electric energy consumption monitoring has been proposed as an important process which makes immediate reductions in energy use and CO(2) emissions. In recent years, advances in electronics have allowed the implementation of many technological solutions that could help to reduce energy consumption. This paper describes the design and prototyping of a home electric energy monitoring system that provides residential consumers with real time information about their electricity use. The system uses wireless communication and displays the information on a small LCD screen and on a computer.

The elastodynamic response of saturated poroelastic media is modelled approximating independently the solid and seepage displacements in the domain and the force and pressure components on the boundary of the element. The domain and boundary approximation bases are used to enforce on average the dynamic equilibrium and the displacement continuity conditions, respectively. The resulting solving system is Hermitian, except for the damping term, and its coefficients are defined by boundary integral expressions as a Trefftz basis is used to set up the domain approximation. This basis is taken from the solution set of the governing differential equation and models the free-field elastodynamic response of the medium. This option justifies the relatively high levels of performance that are illustrated with the time domain analysis of unbounded domains.

Transparent, undoped semiconductive thin films of zinc oxide were deposited by radio frequency plasma enhanced reactive thermal evaporation of zinc rods in the presence of oxygen at room temperature, without any post-deposition annealing treatments. The study of the variation of rf power, in the range 5-200W, on the main properties of these films was made. A decrease of the electrical conductivity of these films with increasing rf power was observed (10(-3) to 10(-12) (Omega cm)(-1)), respectively, while the average visible transparency was kept practically constant (approximate to 80%). From this initial study, a set of bottom-gate type thin-film transistors were made using the most promising semiconductor materials. Preliminary I(V) measurements showed all transistors working, with best results obtained from zinc oxide material deposited at the lowest rf power (20 W), within the deposition conditions range which leads to semiconductive material. Such devices presented an I-on (20 V)/I-off (-5 V) ratio of 6 x 10(6) and a field-effect mobility of 0.37 cm(2)/(V s). (C) 2010 Elsevier B.V. All rights reserved.

Transparent, undoped semiconductive thin films of zinc oxide were deposited by radio frequency plasma enhanced reactive thermal evaporation of zinc rods in the presence of oxygen at room temperature, without any post-deposition annealing treatments. The study of the variation of rf power, in the range 5-200W, on the main properties of these films was made. A decrease of the electrical conductivity of these films with increasing rf power was observed (10(-3) to 10(-12) (Omega cm)(-1)), respectively, while the average visible transparency was kept practically constant (approximate to 80%). From this initial study, a set of bottom-gate type thin-film transistors were made using the most promising semiconductor materials. Preliminary I(V) measurements showed all transistors working, with best results obtained from zinc oxide material deposited at the lowest rf power (20 W), within the deposition conditions range which leads to semiconductive material. Such devices presented an I-on (20 V)/I-off (-5 V) ratio of 6 x 10(6) and a field-effect mobility of 0.37 cm(2)/(V s). (C) 2010 Elsevier B.V. All rights reserved.

Amongst applications of high temperature superconductors, fault current limiters are foreseen as one of the most promising in power systems. Several topologies have been developed in the last years, taking advantage of different superconductors? properties. Increasing distributed generation (DG) penetration, based on renewable energy, adds new short-circuit sources to electrical grids, which brings several energy quality and protection issues. Superconducting fault current limiters can obviate these problems, representing thus an enabling technology for DG penetration. In this paper current limiter topologies are presented, its operations principles, strengths and weaknesses, in the context of these DG grids. In the end, future trends are discussed.

"Given two r-graphs G and H, an H-decomposition of G is a partition of the edge set of G such that each part either is a single edge or forms a graph isomorphic to H. The minimum number of parts in an H-decomposition of G is denoted by φrH(G). By a 2-edge-decomposition of an r-graph we mean an H-decomposition for any fixed r-graph H with exactly 2 edges. In the special cases where the two edges of H intersect in exactly 1, 2 or r−1 vertices, these 2-edge-decompositions will be called bowtie, domino and kite, respectively. The value of the function φrH(n) will be obtained for bowtie, domino and kite decompositions of r-graphs.''