839,216 research outputs found

    Illustrating field emission theory by using Lauritsen plots of transmission probability and barrier strength

    Full text link
    This technical note relates to the theory of cold field electron emission (CFE). It starts by suggesting that, to emphasize common properties in relation to CFE theory, the term 'Lauritsen plot' could be used to describe all graphical plots made with the reciprocal of barrier field (or the reciprocal of a quantity proportional to barrier field) on the horizontal axis. It then argues that Lauritsen plots related to barrier strength (G) and transmission probability (D) could play a useful role in discussion of CFE theory. Such plots would supplement conventional Fowler-Nordheim (FN) plots. All these plots would be regarded as particular types of Lauritsen plot. The Lauritsen plots of -G and lnD can be used to illustrate how basic aspects of FN tunnelling theory are influenced by the mathematical form of the tunnelling barrier. These, in turn, influence local emission current density and emission current. Illustrative applications used in this note relate to the well-known exact triangular and Schottky-Nordheim barriers, and to the Coulomb barrier (i.e., the electrostatic component of the electron potential energy barrier outside a model spherical emitter). For the Coulomb barrier, a good analytical series approximation has been found for the barrier-form correction factor; this can be used to predict the existence (and to some extent the properties) of related curvature in FN plots.Comment: Based on a poster presented at the 25th International Vacuum Nanoelectronics Conference, Jeju, S. Korea, July 2012. Version 3 incorporates small changes made at proof stag

    Barrier functions in the subdifferential theory

    Full text link
    We present a new method for proving Correa-Jofr\'e-Thibault theorem that monotonicity of subdifferential implies convexity of the function. This new method is based on barrier functions. Barrier functions help overcome some of the main technical difficulties when working with lower semicontinuous functions

    Nanoparticulate sol-gel pretreatments as barrier coatings and adhesion promoters for metallic corrosion protection

    Get PDF
    The Spanish University Carlos III de Madrid has developed sol-gel coatings for the corrosion protection of alloys. Sol-gel coatings represent a physical barrier between the metallic substrate and the aggressive environment of exposition and act as adhesion promoters through interfacial bonding. Optimization of the coating’s properties may be easily achivied by changing the processing parameters and formulation of the layer. Interest in licensing the applied patent or technical cooperation with companies that would like to incorporate this technology

    Regulatory Protection When Firms Move First

    Get PDF
    I investigate the imposition of a horizontal technical barrier to trade (HTBT) in a symmetric, cross-hauling duopoly. Tariffs and subsidies are ruled out, but, in the absence of a mutual recognition agreement, it is possible for governments to impose HTBTs, so long as firms apply different technologies. If firms are first movers, this possibility may induce them to avoid technical collaboration, in order to tempt governments into creating local monopolies, except where spillovers and R&D effects are high. This exacerbates the costs of regulatory protection, compared to standard models without R&D or spillovers.Research and development, spillovers, trade, protection.

    Technical-economic optimization of in-situ reactive barrier systems under uncertainty

    Get PDF
    Technical-economic optimization of in-situ reactive barrier systems under uncertaint

    The Tariff Equivalent and Forgone Trade Effects of Prohibitive Technical Barriers to Trade

    Get PDF
    We derive a method to econometrically estimate the tariff equivalent and foregone trade effects of a prohibitive technical barrier to trade (TBT) based on Wales and Woodland's Kuhn-Tucker approach to corner solutions in consumer choice. The method overcomes the lack of observed data on bilateral trade flows and accounts for differentiated goods by place of origin. We apply the derived random utility model to international trade in apples to identify the tariff equivalent of prohibitive nontariff trade barriers imposed by Australia on potential imports of New Zealand apples. We estimate the forgone apple trade between the two countries, the implied trade injury imposed by Australia on New Zealand, and the welfare loss to Australia. The removal of the TBTs would induce net welfare gains around US$50 million annually for Australia.Corner solution; Kuhn-Tucker model; New Zealand apples; nontariff barrier; NTB; prohibitive; random utility; TBT; technical barrier to trade; SPS; phytosanitary

    Classifying the biodiversity of the Great Barrier Reef World Heritage Area for the classification phase of the representative areas program

    Get PDF
    This technical report outlines the methods that the Great Barrier Reef Marine Park Authority used to classify the biodiversity of the marine environs of the Great Barrier Reef World Heritage Area for the Representative Areas Program. Classification was the first step in the multiphase Representative Areas Program that eventuated in a new network of no-take areas, free from extractive activities, in the Great Barrier Reef Marine Park

    Les Probabilités Défaillance comme Indicateurs de Performance des Barrières Techniques de Sécurité - Approche Analytique

    Get PDF
    International audienceFrench environmental laws require industrialists to include probability criteria in risk assessments, especially to define confidence levels for risk management measures. This paper presents the failure probabilities as efficient indicators for technical safety barrier performances. Generic formulas are proposed to evaluate these probabilities, including failure rate, barrier architecture, full and partial proof tests. In many cases, these results can be directly used to assess safety barrier confidence levels
    corecore