Обзор и сравнение программных аналогов для автоматизации деятельности эвент-агентства

В статье представлено описание документооборота и функциональной модели деятельности эвент-агентства. Выявлены функции будущей информационной системы, входная и выходная информация.The article describes the document flow and functional model of the event agency. The functions of the future information system, input and output information have been identified

Towards designing elastic and magnetic properties of Co-based thin film metallic glasses

The fact that metallic glasses combine both metallic properties and characteristics of amorphous materials lead to intensive research worldwide, exploring this interesting class of materials. Co-based metallic glasses, and Co43Fe20Ta5.5B31.5 in particular, offer the attractive combination of both high fracture strength and excellent soft magnetic properties. Within the framework of this thesis, the generation, validation and implementation of a first principles model for Co43Fe20Ta5.5X31.5 (X=B,Si,P,S) metallic glasses are described. This model allows for the identification of valence-electron-concentration and size-induced changes in structure, elastic and magnetic properties and hence contributes towards a knowledge based design of metallic glasses in the future. Within the generated ab-initio model stoichiometric body centered cubic supercells are assumed as initial configurations. After annealing at 4000 K, all cells were quenched down to 0 K at different cooling rates and subsequently relaxed in terms of atomic positions and volumes. To validate this first principles model, density and elastic modulus as well as the pair distribution function and volume magnetization of sputtered Co-Fe-Ta-(B/Si) thin film metallic glasses were measured. The computationally obtained density and stiffness values as well as the theoretical pair distribution function of Co-Fe-Ta-B and the volume magnetization of the Si-containing alloy are consistent with experimental data obtained for thin films and with literature data. The infinite cooling rate to quench the molten alloy was determined to be sufficient. The implementation of the for Co-Fe-Ta-(B/Si) successfully validated first principles model was realized by analyzing short range order, charge transfer and the bonding nature by means of density of states, Bader decomposition and pair distribution function analysis. For Co43Fe20Ta5.5X31.5 (X=B,Si,P,S) a clear trend of a decrease in density and bulk modulus as well as a weaker cohesion was observed as the valence electron concentration for the X element is increased by replacing B with Si and further with P and S. This observed trend upon X variation may be understood based on increased interatomic distances, variations in coordination numbers and the electronic structure changes: As the valence electron concentration of X is increased, the X bonding becomes more ionic. This factor disrupts the overall metallic interactions and leads to weaker cohesion and stiffness. Density of states as well as pair distribution functions are used to identify (Co,Fe)-X atomic pairs as the shortest and strongest constituents. These strong bonds may give rise to a comparatively large stiffness. The highest magnetic moments – and the largest population of unpaired transition metal d states – are identified for X=S, despite the fact that the presence of X generally reduces the magnetic moment of Co. The interplay between transition metal d band filling and s-d hybridization was hence identified to be a key materials design criterion. Furthermore, an extended diagonal relationship between the B- and P-containing amorphous alloys (in coherence to the known relationship between elements of the second and third period) was revealed. This thesis indicates that systematic quantum mechanics simulations enable the identification of composition-induced changes in short range order, charge transfer and bonding nature of metallic glasses. These characteristics are correlated with density, elasticity and magnetism. The here identified property-electronic structure correlations may thus provide the basis for future knowledge based design of glassy materials

Temperature-Induced Short-Range Order Changes in Co67B33 Glassy Thin Films and Elastic Limit Implications

In situ high-temperature X-ray diffraction experiments using high-energy photons and ab initio molecular dynamics simulations are performed to probe the temperature-induced changes in the topological short-range order in magnetron sputtered Co67B33 metallic glass thin films. Based on this correlative experimental and theoretical study, the presence of B–Co–B rigid second-order structures at room temperature and the temperature-induced decrease in the population of these strongly bonded building blocks are inferred. This notion is consistent with experimental reports delineating the temperature dependence of elastic limit

Ab initio molecular dynamics model for density, elastic properties and short range order of Co–Fe–Ta–B metallic glass thin films

Density, elastic modulus and the pair distribution function of Co-Fe-Ta-B metallic glasses were obtained by ab-initio molecular dynamics simulations and measured for sputtered thin films using X-ray reflectivity, nanoindentation and X-ray diffraction using high energy photons. The computationally obtained density of 8.19 g/cm3 for Co43Fe20Ta5.5B31.5 and 8.42 g/cm3 for Co45.5Fe24Ta6B24.5, as well as the Young’s moduli of 273 and 251 GPa, respectively, are consistent with our experiments and literature data. These data, together with the good agreement between the theoretical and the experimental pair distribution functions, indicate that the here established model is useful to describe density, elasticity and short range order of Co-Fe-Ta-B metallic glass thin films. Irrespective of the investigated variation in chemical composition, (Co,Fe)-B cluster formation and Co-Fe interactions are identified by density of states analysis. Strong bonds within the structural units and between the metallic species may give rise to the comparatively large stiffness