6 research outputs found

    Ground state of a confined Yukawa plasma

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    The ground state of an externally confined one-component Yukawa plasma is derived analytically. In particular, the radial density profile is computed. The results agree very well with computer simulations on three-dimensional spherical Coulomb crystals. We conclude in presenting an exact equation for the density distribution for a confinement potential of arbitrary geometry.Comment: 5 pages, 4 figure

    Cu–Au nanoparticles produced by the aggregation of gas‐phase metal atoms for CO oxidation

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    Abstract Alloy nanoparticles (nanoalloys) are widely applied in heterogeneous catalysts, advanced electrodes, biomaterials, and other areas. The properties of nanoalloys can be tuned to a significant extent by their structures and compositions, which are governed by the employed synthetic procedure. Often such synthesis occurs in non‐equilibrium conditions and yields nanoalloys with structures and properties that are different from those obtained in thermodynamic equilibrium. In this work, we characterize how the non‐equilibrium conditions during the synthesis of Cu–Au alloys via physical vapor deposition (PVD) affect their morphology, composition, electronic structure, and reactivity in CO oxidation. We used molecular dynamics to simulate the PVD synthesis of Cu–Au nanoalloys through the non‐isothermal aggregation of Cu and Au atoms at a 3:1 ratio in the Ar atmosphere to obtain realistic structures of Cu–Au nanoparticles. Due to the different aggregation kinetics of Au and Cu atoms, the average Au concentration in the obtained Cu–Au particles varied between 14% and 50% depending on the nanoparticle size and the aggregation time. Density functional simulations revealed that the reactivity of the obtained Cu–Au clusters toward CO and oxygen as well as Brønsted–Evans–Polanyi relations for CO oxidation significantly depend on whether the clusters had fcc, icosahedral, or amorphous structures and do not strongly correlate with the d‐band centers of the adsorption sites. Our study highlights the importance of the non‐equilibrium character of nanoalloy structure and composition for their electronic structure and catalytic properties. The performed analysis of the reactivity of Cu–Au clusters with realistic structures in CO oxidation will help the optimization of Cu–Au catalysts for this societally important reaction

    Use of technology replication in a control system of databases

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    Рассматривается репликация как технология приведения баз данных, функционирующих в распределенной среде в актуальное состояние, за счет выявления измененных данных, передачи и применение этих изменений в базе данных получателя.Розглядається реплікація як технологія приведення баз даних, функціонуючих у розподіленому середовищі в актуальний стан, за рахунок виявлення змінених даних, передачі й застосування цих змін у базі даних одержувача.It is considered replication as technology of reduction of databases, functioning in the distributed environment in an actual condition, due to revealing the changed data, transfer and application of these changes in a database of the addressee

    Some results of full-scale experiments to study the effect of forest fires on atmospheric characteristics

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    The article presents the results of a series of mesoscale experiments to study wildfires and their impact on the atmosphere. A change in meteorological parameters, a significant increase in fluctuations of the refractive index, speed of sound and temperature in the vicinity of the experiment, which are a reflection of the occurrence of turbulent processes in the atmosphere, were established, experimental data were obtained on changes in the concentration of methane and carbon dioxide as a result of a fire, and data were obtained on the mechanism of occurrence of crown fire
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