66 research outputs found

    Information technology as a tool to improve the competitiveness of the organization

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    In this article we are talking about competitiveness and how competitiveness is enhanced through information technology

    Two Dimensional Ir-Cluster Lattices on Moir\'e of Graphene with Ir(111)

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    Lattices of Ir clusters have been grown by vapor phase deposition on graphene moir\'{e}s on Ir(111). The clusters are highly ordered, spatially and thermally stable below 500K. Their narrow size distribution is tunable from 4 to about 130 atoms. A model for cluster binding to the graphene is presented based on scanning tunneling microscopy and density functional theory. The proposed binding mechanism suggests that similar cluster lattices might be grown of materials other than Ir.Comment: Submitted to PRL on 27Apr0

    Ab-Initio Step- and Kink-Formation Energies on Pb(111)

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    Ab-initio formation energies for (100)- and (111)-microfacet steps on Pb(111) are in satisfactory agreement with measured values, given that these values are known only as well as the Pb(111) surface energy; the calculated step-energy ratio, 1.29, is within {approximately}8% of experiment. In contrast, calculated kink-formation energies, 41 and 60 meV for the two step types, are 40--50% below published experimental values derived from STM images. The discrepancy results from interpreting the images with a step-stiffness vs. kink-energy relation appropriate to (100) but not (111) surfaces. Good agreement is found when the step-stiffness data are reinterpreted, taking proper account of the trigonal symmetry of Pb(111)

    Entropy of H 2

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    Kinetics and thermodynamics of carbon segregation and graphene growth on Ru(0001)

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    We measure the concentration of carbon adatoms on the Ru(0001) surface that are in equilibrium with C atoms in the crystal's bulk by monitoring the electron reflectivity of the surface while imaging. During cooling from high temperature, C atoms segregate to the Ru surface, causing graphene islands to nucleate. Using low-energy electron microscopy (LEEM), we measure the growth rate of individual graphene islands and, simultaneously, the local concentration of C adatoms on the surface. We find that graphene growth is fed by the supersaturated, two-dimensional gas of C adatoms rather than by direct exchange between the bulk C and the graphene. At long times, the rate at which C diffuses from the bulk to the surface controls the graphene growth rate. The competition among C in three states - dissolved in Ru, as an adatom, and in graphene - is quantified and discussed. The adatom segregation enthalpy determined by applying the simple Langmuir-McLean model to the temperature-dependent equilibrium concentration seriously disagrees with the value calculated from first-principles. This discrepancy suggests that the assumption in the model of non-interacting C is not valid

    Self-diffusion along step bottoms on Pt(111)

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    First-principles total energies of periodic vicinals are used to estimate barriers for Pt-adatom diffusion along straight and kinked steps on Pt(111), and around a corner where straight steps intersect. In all cases studied, hopping diffusion has a lower barrier than concerted substitution. In conflict with simulations of dendritic Pt island formation on Pt(111), hopping from a corner site to a step whose riser is a (111)-micro facet is predicted to be more facile than to one whose riser is a (100)

    Разработка и программная реализация алгоритма детектирования номерных знаков на изображениях

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    Объектом исследования является задача определения расположения номерной пластины на изображении. Цель работы – разработка и программная реализация алгоритмов детектирования номерных знаков. В процессе исследования были изучены и проанализированы существующие методы детектирования номерных знаков, методы текстурной сегментации изображений и методы предобработки изображения. В результате исследования был предложен и реализован алгоритм детектирования номерных знаков на изображениях. Программное обеспечение позволит детектировать номерные знаки автомобилей. Может быть востребовано в системах контроля и регистрации автомобилей и других видов транспортных средств.The object of study is the problem of determining the location of the license plate in the image. The work purpose – development and software implementation of algorithms for the detection of license plates. In the research process was studied and analyzed existing methods of license plate detection methods, texture segmentation of images and methods of image preprocessing. The study was proposed and implemented algorithm detecting license plates in images.The software will detect number plates of cars. It can be used in the systems of control and registration of cars and other types of vehicle

    Light emission from a scanning tunneling microscope: Fully retarded calculation

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    The light emission rate from a scanning tunneling microscope (STM) scanning a noble metal surface is calculated taking retardation effects into account. As in our previous, non-retarded theory [Johansson, Monreal, and Apell, Phys. Rev. B 42, 9210 (1990)], the STM tip is modeled by a sphere, and the dielectric properties of tip and sample are described by experimentally measured dielectric functions. The calculations are based on exact diffraction theory through the vector equivalent of the Kirchoff integral. The present results are qualitatively similar to those of the non-retarded calculations. The light emission spectra have pronounced resonance peaks due to the formation of a tip-induced plasmon mode localized to the cavity between the tip and the sample. At a quantitative level, the effects of retardation are rather small as long as the sample material is Au or Cu, and the tip consists of W or Ir. However, for Ag samples, in which the resistive losses are smaller, the inclusion of retardation effects in the calculation leads to larger changes: the resonance energy decreases by 0.2-0.3 eV, and the resonance broadens. These changes improve the agreement with experiment. For a Ag sample and an Ir tip, the quantum efficiency is \approx 104^{-4} emitted photons in the visible frequency range per tunneling electron. A study of the energy dissipation into the tip and sample shows that in total about 1 % of the electrons undergo inelastic processes while tunneling.Comment: 16 pages, 10 figures (1 ps, 9 tex, automatically included); To appear in Phys. Rev. B (15 October 1998

    A PhD is not enough!: a guide to survival in science

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    A Ph. D. Is Not Enough! is required reading for anyone thinking of applying to graduate school or entering the science job market. Focusing on critical survival skills, it offers sound advice on selecting a thesis or postdoctoral adviser; choosing among research jobs in academia, government laboratories, and industry; and defining a research program. This new edition features updates throughout and a new chapter reflecting todays rapidly changing world
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