Persons

Recently, in the components of the lithium-ion accumulators (LIA) an anomalously diffusion behavior of ion transport has been discovered. Currently, the microscopic models LIA, consecutively taking into account sub- or superdiffusion and percolation of lithium ions into LIA, are unavailable. The semi-empirical LIA models, using the fractional-order impedances, based on the impedances of fractional order, which are substantiated by the anomalous diffusion of ions in a percolative disordered medium are becoming popular. In the work an assessment of the influence of anomalous diffusion on the impedance spectra within the framework of sub-diffusion generalization of the electrochemical model has been carried out. Using the subdivision equations with the time derivatives of fractional order, the LIA electrochemical model has been modified. Within the framework of this model, using the Fourier transform of fractional differential operators, an equivalent circuit, generalizing popular LIA circuit models has been derived. It has been shown that the slope of a rectilinear low-frequency part of the Nyquist diagram does not always unambiguously determine the subdivision coefficient α and can be both larger and smaller than the slope corresponding to normal diffusion. It has been stipulated that the degradations of the battery properties is associated with a change of the diffusion type in the LIA components.

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Interaction of the electromagnetic radiation with the magnetofunctionalized CNT-nanocomposite is considered within the model of distributedrandom resistive-inductance-capacitor contours. The approach is based on the presentation of the nanocomposite as a system consisting of CNT matrix, ferromagnetic nanoparticles and interfaces between CNT and nanoparticles. Calculations reveal a wide spectrum of possible resonance phenomena caused both by the presence of contours and peculiarities of CNT nanocomposite by itself.

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Some features of the 3D silicon structures formation by locally formation of porous silicon as a sacrificial layer have been studied. It has been formed by metal-assisted chemical etching of a single crystal wafer of Si with silver films (50 and 100 nm) as a catalyst. The influence of ionic Ag mass transfer, caused by the temperature gradient, on the surface morphology of the formed structure according to the linear size of the mask-catalyst has been determined.

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The analysis of the current and future developments in the field of the power elements based on the ß-decay has been executed. The possible technologies of creation have been described and the calculations of the efficiency for produced by them power sources have been presented. The possibility of creating a self-charging supercapacitor based on CNTs using isotope Ni63 and C14 has been examined. The theoretical calculation, confirming the perspectives of selecting the fields of investigations, has been performed.

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A model of the nucleation thermodynamics, which takes into account the surface tension value, has been developed. The experiments on formation of the iron clusters formed during the process of ferrocene clusters pyrolysis at various temperatures have been conducted. Based on the theoretical and experimental data the methods for determining the temperature dependence of the surface tension of nano-dimensional clusters have been developed, and the influence of this parameter on the size distribution of clusters has been shown.

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The possibility of the synthesis of carbon nanotubes by the method of chemical deposition of acetylene at 400-800 °C temperature on the surface of a metal film of amorphous alloy Ni-Ta-N with low nickel content (~ 25 at.%) has been demonstrated. It has been shown that an addition of nitrogen into the Ni-Ta alloy promotes the formation of tantalum nitride and extrusion on the surface of the nickel clusters, acting as a catalyst in the growth of carbon nanotubes. The Raman spectroscopy has revealed that while increasing the temperature of the synthesis process the quality of the carbon nanotubes is improved.

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The thermodynamics of the metal nanocluster formation has been developed. An expression for the distribution function of clusters by sizes depending on their production condition has been obtained. It has been shown that the surface tension plays an important role in the cluster formation. The surface tension coefficient value for the iron clusters at 950°C has been found.

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