196 research outputs found

    Business objects: the next step in component technology?

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    Component technology seems to be a promising approach towards more efficient software development by enabling application construction through “plug and play”. However, the middleware supporting this approach is still complicated to use and distracts the attention of the component developer from the application domain to technical implementation issues. Business objects are intended to hide the complexities of middleware approaches and provide an easy to use environment for application developers. We conceptualize business object approaches by presenting a common model and survey some major players in the marketplace. We conclude by identifying implications of business objects on information systems engineering.

    TIGRA - An architectural style for enterprise application integration

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    EFEITO DA SALINIDADE E DA TEMPERATURA SOBRE CRESCIMENTO DE 4 MICROALGAS MARINHAS:: “Efeito da salinidade e da temperatura sobre o crescimento da nannochloropsis oculata e da isochrysis galbana”

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    Diferentes salinidades (15, 20, 25 e 30‰) e temperaturas (20 e 25 ± 1°C) foramavaliadas para determinar as melhores condições de crescimento emNannochloropsis oculata e Isochrysis galbana durante 14 dias. Culturas com 10 diasde idade foram utilizadas como inóculo (1 x 10⁴ cells mL‾1) em meio F/2 de Guillardmodificado, iluminadas continuamente por 6 lâmpadas de led (2000Lm). Concluiu-seque tanto a Nannochloropsis sp. quanto a Isochrisis sp. conseguiram crescer entre assalinidades 15‰ e 30‰ nas duas temperaturas avaliadas. Para ambas algas ocrescimento foi melhor quando cultivada a 25°C

    Identification and design principles of low hole effective mass p-type transparent conducting oxides

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    The development of high-performance transparent conducting oxides is critical to many technologies from transparent electronics to solar cells. Whereas n-type transparent conducting oxides are present in many devices, their p-type counterparts are not largely commercialized, as they exhibit much lower carrier mobilities due to the large hole effective masses of most oxides. Here we conduct a high-throughput computational search on thousands of binary and ternary oxides and identify several highly promising compounds displaying exceptionally low hole effective masses (up to an order of magnitude lower than state-of-the-art p-type transparent conducting oxides), as well as wide band gaps. In addition to the discovery of specific compounds, the chemical rationalization of our findings opens new directions, beyond current Cu-based chemistries, for the design and development of future p-type transparent conducting oxides.United States. Office of Naval Research (Award N00014-11-1-0212

    Hybrid crystalline-ITO/metal nanowire mesh transparent electrodes and their application for highly flexible perovskite solar cells

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    Here, we propose crystalline indium tin oxide/metal nanowire composite electrode (c-ITO/metal NW-GFRHybrimer) films as a robust platform for flexible optoelectronic devices. A very thin c-ITO overcoating layer was introduced to the surface-embedded metal nanowire (NW) network. The c-ITO/metal NW-GFRHybrimer films exhibited outstanding mechanical flexibility, excellent optoelectrical properties and thermal/chemical robustness. Highly flexible and efficient metal halide perovskite solar cells were fabricated on the films. The devices on the c-ITO/AgNW- and c-ITO/CuNW-GFRHybrimer films exhibited power conversion efficiency values of 14.15% and 12.95%, respectively. A synergetic combination of the thin c-ITO layer and the metal NW mesh transparent conducting electrode will be beneficial for use in flexible optoelectronic applications

    Tuning of Electrical and Optical Properties of Highly Conducting and Transparent Ta-Doped TiO2 Polycrystalline Films

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    We present a detailed study on polycrystalline transparent conducting Ta-doped TiO2 films, obtained by room temperature pulsed laser deposition followed by an annealing treatment at 550°C in vacuum. The effect of Ta as a dopant element and of different synthesis conditions are explored in order to assess the relationship between material structure and functional properties, i.e. electrical conductivity and optical transparency. We show that for the doped samples it is possible to achieve low resistivity (of the order of 5×10-4 Ωcm) coupled with transmittance values exceeding 80% in the visible range, showing the potential of polycrystalline Ta:TiO2 for application as a transparent electrode in novel photovoltaic devices. The presence of trends in the structural (crystalline domain size, anatase cell parameters), electrical (resistivity, charge carrier density and mobility) and optical (transmittance, optical band gap, effective mass) properties as a function of the oxygen background pressures and laser fluence used during the deposition process and of the annealing atmosphere is discussed, and points towards a complex defect chemistry ruling the material behavior. The large mobility values obtained in this work for Ta:TiO2 polycrystalline films (up to 13 cm2V-1s-1) could represent a definitive advantage with respect to the more studied Nb-doped TiO2

    Deposition of Aluminum-Doped ZnO Films by ICP-Assisted Sputtering

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    Inductively coupled plasma (ICP) assisted DC sputter deposition was used for the deposition of Al-doped ZnO (AZO or ZnO:Al) thin films. With increasing ICP RF power, film properties including deposition rate, crystallinity, transparency, and resistivity were improved. To understand the plasma-surface interaction, several plasma diagnostics were performed. Heat fluxes to the substrate were measured by thermal probes, number densities of sputtered metallic atom species were measured by absorption spectroscopy using hollow cathode lamps (HCL) and light emitting diodes (LEDs), and neutral gas temperatures were measured by external cavity diode laser (ECDL) absorption spectroscopy. As a result, it was revealed that the high-density ICP heated the substrate through a high heat flux to the substrate, resulting in a high-quality film deposition without the need for intentional substrate heating. The heat flux to the substrate was predominantly contributed by the plasma charged species, not by the neutral Ar atoms which were also significantly heated in the ICP. The substrate position where the highest quality films were obtained was found to coincide with the position where the substrate heat flux took the maximum value

    Interactions between metal oxides and biomolecules: from fundamental understanding to applications

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    Metallo-oxide (MO) based bioinorganic nanocomposites promise unique structures, physico-chemical properties and novel bio-chemical functionalities and within the last decade, investment in research on materials such as ZnO, TiO2, SiO2 and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning and post-processing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces and the behaviour of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution we present a critical review of recent advances in the chemistry and engineering of MO based biocomposites highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials
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