Zaporozhe, Ukraine
Zaporozhe, Ukraine

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Chepkunov R.A.,VAT NDI Peretvoriuvach | Levinzon D.I.,Classic private University
Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu | Year: 2014

Purpose. Generalization of the results of studies of the electric drive features with indirect speed measuring associated with the presence of the positive current feedback, with the significant voltage feedback pulsations in DC motor, with display of instability of the induction motor, and consideration of their practical use to improve the control quality. Methodology. The methods for improving of the control quality through: full compensation of droop mechanical characteristics of the motor at a certain average temperature of the windings with the assumption of overcompensation by the temperature changes; reducing of the inertia of the voltage sensor by a digital smoothing its signal in the microprocessor control system in DC drive; sustain of stability of the induction motor in AC drive. Findings. Defined the fields of stability of control system at positive current feedback in DC drive and at active current feedback in asynchronous electric drive. Defined the fields of stability of control loop with thyristor converter at digital smoothing of feedback signal. Defined the fields of stability of the induction motor as a function of the coefficient of the magnetic flux scattering, electromechanical time constant, time constants of the stator and rotor. Substantiated the control structures and system parameters that provide quality control of the electric drives. Originality. Methods of choosing the parameters of the speed controller at the positive current feedback. Conditions of stability of control loop with thyristor converter at digital smoothing of feedback signal. Stability boundaries of the induction motor subject to the coefficient of the magnetic flux scattering, electromechanical time constant and the time constants of rotor and stator. Improvement of the control structures of electric drives with the indirect speed measuring. Practical value. Implementation of the results of research in electric AC and DC drives produced by Zaporizhia Electrical Apparatus Plant and Science Research Institute of the Power Electronics. © 2014 State Higher Educational Institution "National Mining University".

Talanin V.I.,Classic Private University | Talanin I.E.,Classic Private University
Physics of the Solid State | Year: 2010

The formation of vacancy microvoids and A-microdefects has been calculated according to the model of point defect dynamics in the absence of recombination of intrinsic point defects at high temperatures. It has been assumed that this solution is possible in the case where the precipitation of impurities begins in the vicinity of the crystallization front. It has been demonstrated that the formation of vacancy microvoids has a homogeneous nature and that the interstitial dislocation loops are predominantly formed through the deformation mechanism. © 2010 Pleiades Publishing, Ltd.

Ivanov V.M.,Classic Private University | Trubitsyn Yu.V.,Classic Private University
Tsvetnye Metally | Year: 2013

This work is devoted to the design features of the PIC-reactors of synthesis of trichlorosilane, which is used in the production of polycrystalline silicon. Trichlorosilane is produced by the hydrochlorination of technical silicon and hydrogenation of silicon tetrachloride, formed during the polysilicon production as a byproduct. Modern technologies make it possible to apply the process of hydrogenation of silicon tetrachloride to trichlorosilane, which is recycled to the production of polysilicon. There are described the known designs of PIC-reactors developed for the synthesis of trichlorosilane. In the synthesis practice the reactors with gushing bed and suspended bed have found their application. The design features of the reactors hydrochlorination of silicon and hydrogenation of silicon tetrachloride are examined. Gushing bed reactors are equipped with conical bottom with the function of the gas distributing cone, cylindrical or conical shell and expander for separation of particles, carried away by the gas stream from the reaction zone. Reactors with the suspended bed have a cylindrical or conical shell with built-in gas-distributing grid. For pre-heating of silicon load and ensuring of optimum reaction temperature the reactors can be equipped with the heaters. For the purpose of removement of heat of exothermic reactions, the heat-exchange elements are foreseen in the reactors designs. The advantages and disadvantages of the reactors designs are present taking into account their design features and operating experience. There are given the proposals for usage of reactors with gushing bed and suspended bed. There was made the conclusion that the development and implementation of the suspended bed reactor is the most reasonable for the catalytic hydrogenation, which is nowadays considered as promissing.

Khrypko S.L.,Classic Private University | Zholudev G.K.,Classic Private University
Journal of Nano- and Electronic Physics | Year: 2011

Simulating model for photovoltaic cell in order to estimate electric behavior with respect changes on environmental varying parameters of temperature and solar insulation, varying diode model parameters, such as series and shunt resistance. The simulation is done with the aid of Ìatlab environment.

Khrypko S.L.,Classic Private University
Journal of Surface Investigation | Year: 2014

The Raman scattering spectra of porous p−- and p+-silicon with a porosity of 20–70% are investigated. Conclusions on the morphology of silicon nanocrystallites are made based on this. It is shown that their size and shape depend on the level of sample doping. The crystallites are comprised of nanowires with diameter 6–9 nm or nanospheres with diameter 3–5 nm. An increase in porosity causes the broadening of spectral lines and their shift toward shorter wavelengths. © 2014, Pleiades Publishing, Ltd.

Bakhrushin V.E.,Classic Private University | Gorban A.N.,Classic Private University
Ukrainian Journal of Physical Optics | Year: 2011

The article deals with the problems related to quality of the tests applied in education, in particular with regard to the External Independent Evaluation recently introduced in Ukraine.

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