1,434 research outputs found

    A Criterion for the Critical Number of Fermions and Chiral Symmetry Breaking in Anisotropic QED(2+1)

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    By analyzing the strength of a photon-fermion coupling using basic scattering processes we calculate the effect of a velocity anisotropy on the critical number of fermions at which mass is dynamically generated in planar QED. This gives a quantitative criterion which can be used to locate a quantum critical point at which fermions are gapped and confined out of the physical spectrum in a phase diagram of various condensed matter systems. We also discuss the mechanism of relativity restoration within the symmetric, quantum-critical phase of the theory.Comment: To appear in Physical Review

    Analytical Characterization of Volatile Active Principles from the Leaves of the Alboroseum Backer Plant

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    The study presents for the first time the data concerning the qualitative and quantitative determination of the volatile active principles from the leaves of the Alboroseum Backer plant (Crassulaceae). After the extraction of volatile active principles in water, analytical separation and quantitative determination using a GC/MS technique was performed. The compounds detected, are belonging to the following classes: aldehydes, ketones, aromatic hydrocarbons and alcohols. South African Journal of Chemistry Vol.55 2002: 67-7

    PHOTOVOLTAIC PRODUCTION MANAGEMENT IN STOCHASTIC OPTIMIZED MICROGRIDS

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    The microgrids are composed of small scale fueled generation capacities, renewable energy sources, storage energy systems, controllable loads, and autonomously can connect or disconnect from the mains supply. The microgrids can operate connected to the upstream main grid, or in an islanded operation mode following a large perturbation in the upstream grid. The microgrid analyzed in this paper is composed of a photovoltaic system, a thermal engine, an electrochemical storage system, critical and interruptible loads. As backup generation is considered a classical generation engine and a small scale storage unit. The autonomous switching between grid-connected and islanding operation modes can occur, under an excess/deficit of generation and function of the electricity market price. The paper deals with an optimization model for minimizing the microgrid operation costs under intermittent generation and variable demand function of microgrid operation constrains. The optimization model is tested on a 24 hours horizon. The gridconnected optimized operation accounts also the exchanged power with the upstream grid function of the electricity price within the public network

    Quantum Transport in a Nanosize Silicon-on-Insulator Metal-Oxide-Semiconductor

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    An approach is developed for the determination of the current flowing through a nanosize silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFET). The quantum mechanical features of the electron transport are extracted from the numerical solution of the quantum Liouville equation in the Wigner function representation. Accounting for electron scattering due to ionized impurities, acoustic phonons and surface roughness at the Si/SiO2 interface, device characteristics are obtained as a function of a channel length. From the Wigner function distributions, the coexistence of the diffusive and the ballistic transport naturally emerges. It is shown that the scattering mechanisms tend to reduce the ballistic component of the transport. The ballistic component increases with decreasing the channel length.Comment: 21 pages, 8 figures, E-mail addresses: [email protected]

    Особливості формування Державного бюро розслідувань

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    Балабан В. В. Особливості формування Державного бюро розслідувань / В. В. Балабан // Державне бюро розслідувань: на шляху розбудови : матер. Міжнар. наук.-практ. конф. (м. Одеса, 16 червня 2018 р.) / редкол.: Г. О. Ульянова (голова ред.), В. М. Дрьомін, Є. Л. Стрельцов [та ін.] ; НУ "ОЮА". - Одеса : Юридична література, 2018. - С. 81-83
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