Raman spectra of silicon/germanium alloy thin films based on porous silicon

Regularities of composition changes of silicon/germanium alloy thin fi lms formed on a single-crystalline silicon substrate by electrochemical deposition of germanium into a porous silicon matrix with subsequent rapid thermal annealing (RTA) at temperatures of 750–950 °C are studied. An analysis of the samples by Raman spectroscopy showed that an increase of the RTA temperature leads to a decrease in the germanium concentration in the formed fi lm. A decrease of the RTA duration at a given temperature makes it possible to obtain fi lms with a higher germanium concentration and to control the composition of thin silicon/germanium alloy fi lms formed by changing the RTA temperature and duration. The obtained results on controlling the composition of silicon/germanium alloy fi lms can be used to create functional electronic devices, thermoelectric power converters, and optoelectronic devices

A new approach for producing of film structures based on Si1-xGex

In this work, we propose a new, previously unpresented in the literature, approach to the formation of Si1-xGex films. This approach includes electrochemical processes of the formation of porous silicon, electrochemical deposition of low-melting metals and Ge. Post-heat treatment is made possible to synthesize film structures based on Si1-xGex solid solutions. Using this approach an alloy of the composition Si0.4Ge0.6 has been obtained at a lower formation temperature than predicted by the phase diagram for the Si-Ge system

Implementation of flat slab column reinforced concrete frames in low cost housing construction

In research presents an analysis of flat slab column reinforced concrete frames in low cost housing construction. The features of precast flat slab column conduit within reinforced concrete frame building have been analyzed. The problems in designing flat slab column frame to improve its reliability are under consideration. Suggestions concerning the ways of improving flat slab column frame building calculations are presented. Precast flat slab column frame constructive system is promising for construction of residential and public buildings. In order to reduce the values of bending moments in the joints of columns, it is suggested to apply solid diaphragms with the functions of taking up the vertical loads in order to take up horizontal loads. It seems reasonable to define the required amount of reinforcement bars in plates by means of the kinematic limit equilibrium method

Algorithms synthesis and potentiality analysis of optimum ultrawideband signal processing in the radiometric system with modulation

Algorithms estimate the parameters of UWB radiothermal signals in single-antenna radiometers with modulation are synthesized and investigated within the bounds of method of maximum likelihood. Based on analysis of the matrix inverse to the Fisher information matrix the potential accuracy of estimates of measured parameters and the sensitivity of radiometric systems are investigated

Optimal signal processing for radiometric imaging with multi-antenna & multi-band passive radars

The optimal algorithm of multiband spatio-temporal radiometric signal processing is synthesized. Analytical expressions both for the potential fluctuation sensitivity of the system designed according to the algorithm and for the ambiguity function of multiband radiometric systems are deduced. An example of the theory application is demonstrated

Effect of Polysaccharide Additions on the Anion-Exchange Deposition of Cobalt Ferrite Nanoparticles

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.A facile and rapid method easily reproducible in ordinary laboratory settings is proposed for preparing nanosized cobalt ferrite powders, where the precipitate used is a strongly basic anion exchange resin in the OH form. The effects caused by additions of polysaccharides having various chain natures and various molar weights on the composition, yield, and particle size of the deposition product are studied. Suggested mechanisms underlying these effects are studied. This method makes it possible to appreciably reduce the precursor annealing temperature compared to that in the state-of-art methods for preparing similar oxide systems due to the formation of highly reactive precursors. Optimal conditions are found to prepare stoichiometric precursors such that, once annealed at 600°C, would form a CoFe2O4 pure phase with particle sizes of 10–20 nm. The stability of hydrosols of the thus-prepared cobalt ferrite nanoparticles is studied by dynamic and electrophoretic light scattering. The prepared material is found to be useful for the design of magnetic core–shell hybrid nanostructures. © 2020, Pleiades Publishing, Ltd