Papers by Keyword: Nanosystem

Abstract: Fe@Au is a type of nanoparticle that contains magnetic Fe NPs core with a fine layer of Au NPs synthesized using the Pulsed Laser Ablation in Liquid (PLAL) Method. These Fe@Au NPs characterized by Atomic Force Microscope (AFM), Field Emission Scanning Electron Microscopy (FESEM), and UV-Visible Spectrophotometer. The result was obtained at different laser fluences (1.9, 2.2, and 2.5) J/cm² with fixed pulse duration 5 ns, wavelength 532nm and number of pulse equal 100 pulsed. The obtained mean size of Fe@Au NPs at laser fluence (1.9, 2.2, and 2.5) J/cm² was (63.65, 32.47 and 31.18) nm respectively. UV-Visible Spectrophotometer carves was showed a redshift toward longer wavelength by increasing particle size. Obtained results exhibited that the laser fluence plays a key role in the size, and dispersity of Fe@Au NPs.

Abstract: The paper considers application of the physical and statistical approach to the issue of nanosystems reliability. A general method of solving the main equation in this approach is suggested and the solution in quadratures is obtained in one-dimensional stationary case. It is used to study the behaviour of entropy and the reliability function under certain assumptions. The cases of constant, linear, and quadratic degradation rates are analysed. In the first two cases the results correspond to physical intuition while in the last case (quadratic rate) the formal solution demonstrates counterintuitive behaviour. Numerical correlations between the distribution entropy dynamics and the reliability function are given.

Abstract: The major problem of a powder material authority – the prediction of structural-phase composition in the production of new multicomponent materials by means of the mathematical description and making of the computer software for homogenization processes modeling in the binary metal-metal systems is solved. The objects of study are processes of nanopowders homogenization in solid-state metals nanosystems of the transition elements such as Fe-Mo, Fe-Cu, Fe-Ni, Fe-Cr. A complex theoretical and experimental study of homogeni¬zation processes in solid-state nanosystems is carried out. The analytical dependences of degree of homogenization on time and temperatures of the sintering process are established, the coefficients of mutual diffusion in systems are calculated, physical and chemical model of homogenization are offered, means of the computer nu¬merical analysis with visualization of the studied processes are created. The estimation of convergence of the numerical methods employed are carried out, the accuracy of calculations is determined, estimated calcula¬tions for considered systems are carried out. The obtained results will allow the reduction in the number of real experiments in the creation of new mate¬rials with required properties.

Abstract: Here we describe a simple and effective approach to make silicon-based-nanowires structured materials which can be utilized in a range of high technology electronic devices. The strategy for achieving this objective is to create platforms by lithographic patterning on which the diffusion length of reactive species is controlled during the subsequent heat treatment leading to the growth of aligned and linear nanowires. With this simple and versatile method, a large quantity of nanowires can be readily arranged into interesting configurations. This method is proving very promising for a variety of applications, all of which require considerable selectivity and reproducibility in terms of size, shape and structure, to ensure reliability during their use.

Abstract: Our present analysis will focus on the S(V)LS mechanism. In the S(V)LS process, silicon nanowires are grown by heating the metal-coated silicon substrate at high temperature in an argon and hydrogen atmosphere. Here, we demonstrate the origin of the driving force needed for the metal supersaturation and calculate the binary phase diagrams of Au-Si nanosystems involved in the growth of nanowires. These new diagrams can be used for other purposes helping to improve the understanding of the physical properties of nanostructures. We also answer the challenging question that many researchers have addressed on whether a minimum size limit of silicon nanowires exists. The nanowire size limit has been evaluated on the basis of thermodynamics and using silicon nanowires obtained via the S(V)LS rather than the VLS mechanism. At 1100°C, the temperature commonly used for the growth of nanowires by the S(V)LS mechanism, it has been found that there is no minimum size limit of nanowires.

Abstract: The separation kinetics in a binary nanoparticle is studied by means of two-dimensional Monte-Carlo sampling and Ising-type model, where the species exchange positions due to vacancy mechanism. The model is developed in case of a free nanoparticle with a coating shell. The kinetics is shown to depend on the size of a nanosystem. We demonstrate a distinct size-induced freezing effect on kinetics of separation.