Peter The Great St Petersburg Polytechnical University

Saint Petersburg, Russia

Peter The Great St Petersburg Polytechnical University

Saint Petersburg, Russia
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Evazzade I.,Ferdowsi University of Mashhad | Lobzenko I.P.,RAS Institute for Metals Superplasticity Problems | Korznikova E.A.,RAS Institute for Metals Superplasticity Problems | Ovid'Ko I.A.,Peter The Great St Petersburg Polytechnical University | And 2 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2017

In the present molecular-dynamics study, external ac driving is used at frequencies outside the phonon spectrum to excite gap DBs in uniformly strained graphene nanoribbon. Harmonic displacement or harmonic force is applied to a zigzag atomic chain of graphene. In the former case, nonpropagating DBs are excited on the atoms next to the driven atoms, while in the latter case the excited DBs propagate along the nanoribbon. The energy transfer along the nanoribbon assisted by the DBs is investigated in detail, and the differences between harmonic displacement driving and harmonic force driving are discussed. It is concluded that the amplitude of external driving at out-of-phonon spectrum frequencies should not necessarily be large to obtain a noticeable energy transfer to the system. Overall, our results suggest that external harmonic driving even at relatively small driving amplitudes can be used to control excitation of DBs and consequently the energy transfer to the system. © 2017 American Physical Society.


Burkov I.V.,Peter The Great St Petersburg Polytechnical University
2015 International Conference on "Stability and Control Processes" in Memory of V.I. Zubov, SCP 2015 - Proceedings | Year: 2015

In some cases the desired uniform motion may be described by a pair of first integrals of the system with zero control input. The linear-quadratic combination of these two integrals is used to construct Lyapunov function. The control is designed from the condition of decreasing Lyapunov function on the trajectories of the closed loop system. This control may be chosen a priori bounded. This method is applied to stabilize circular motion of a satellite around gravitational center, for stabilization inertia wheel pendulum and for swinging a pendubot. © 2015 IEEE.


Romakhova G.A.,Peter The Great St Petersburg Polytechnical University
Power Technology and Engineering | Year: 2017

Results are presented from a study of the effect of the flow rate of cooling air on the efficiency of gas-turbine units with open air cooling over wide ranges of temperature variation after the combustion chamber, degrees of pressure increase in the compressor, and efficiencies of internal heat-transfer in the blade system. The feasibility of increasing the efficiency of power generating gas-turbine units to 40 – 41% is demonstrated. © 2017 Springer Science+Business Media New York


Rashich A.,Peter The Great St Petersburg Polytechnical University | Fadeev D.,Peter The Great St Petersburg Polytechnical University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

In this paper BER performance of FFT-based trellis receiver for multicarrier signals with spectrally efficient frequency division multiplexing (SEFDM) is evaluated taking into account the impact of nonlinear distortions caused by nonlinear power amplifier (PA). Values of input power back-off (IBO) corresponding to the best BER performance are obtained. The energy efficiency is quantified with energy loss with respect to the system with ideal linear PA. The energy efficiency of considered system is compared with the one of SEFDM system with detection algorithm based on decision diagram and no coding. © Springer International Publishing AG 2016.


Tsybin O.,Peter The Great St Petersburg Polytechnical University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Mechanisms of a fast energetic excitation in a nano-device with an embedded molecular film are discussed herein. Excited intermolecular transport of protons, electrons and other quantum carriers could create communication channels inside a molecular network. We suggest that such channels could be analyzed by means of electron capture dissociation reactions of a protonated peptide, protein or a DNA to reveal the intramolecular pathways of mobile carrier motion in an isolated dehydrated molecule. In general, initial processing stage in a nano-device with a molecular film consists of a target direct activation followed by energy transport from target excitations into a surface molecular film which produces an indirect activation. We analyzed selected indirect molecular excitations produced by a metal or a semiconductor target directly activated by means of a radiofrequency electromagnetic field. Further processing stage after the activation consists of molecular relaxation and transportation phenomena providing nano-electromagnetic field, molecular flow, and communication. © Springer International Publishing Switzerland 2015.


Agafonova N.D.,Peter The Great St Petersburg Polytechnical University | Paramonova I.L.,Peter The Great St Petersburg Polytechnical University
Journal of Engineering Physics and Thermophysics | Year: 2016

The formulas for calculating the characteristic drop size for the mean Sauter diameter have been compared. The question on various forms of the size distribution of drops has been considered. To substantiate the applicability of the compared formulas for calculating the thermohydrodynamics in the circuits of nuclear power plants, experimental data on the wall temperature in a dispersed flow have been used. It has been shown that the Sauter diameter values calculated using the wall temperature in the supercritical region are in good agreement with sparse direct measurements of the drop size in steam–water flows. The drop sizes calculated using the tested formulas obtained for two-component gas–liquid flows or for single-component flows of coolants (various kinds of freons) and liquefied nitrogen turned out to be much lower. It has been shown that it is necessary to recalculate the numerical coefficients in the considered formulas in using them for steam–water flows. © 2016 Springer Science+Business Media New York


Fadeev D.K.,Peter The Great St Petersburg Polytechnical University | Rashich A.V.,Peter The Great St Petersburg Polytechnical University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

In this paper the impact of nonlinear distortions caused by nonlinear power amplifier (PA) is evaluated for BPSK and QPSK Spectrally Efficient Frequency Division Multiplexing (SEFDM) signals. System performance depends on input power back-off (IBO) and SEFDM parameters, such as modulation scheme, frequency spacing between subcarriers and total number of subcarriers. Performance is quantified with total degradation (TD), defined as the sum (in decibels) of the IBO and the increment Δ in the ratio Eb/No required to maintain a given bit error rate (BER) with respect to the situation of perfectly linear PA. IBO corresponding to minimum TD is obtained. © Springer International Publishing Switzerland 2015.


Shevkunov S.V.,Peter The Great St Petersburg Polytechnical University
Colloid Journal | Year: 2016

Computer simulation has been employed to study the effect of a confined space of a planar model pore with structureless hydrophobic walls on the hydration of Na+Cl– ion pairs in water vapor at room temperature. A detailed many-body model of intermolecular interactions has been used. The model has been calibrated relative to experimental data on the free energy and enthalpy of the initial reactions of water molecule attachment to ions and the results of quantum-chemical calculations of the geometry and energy of Na+Cl– (H2O)N clusters in stable configurations, as well as spectroscopic data on Na+Cl– dimer vibration frequencies. The free energy and work of hydration, as well as the adsorption curve, have been calculated from the first principles by the bicanonical statistical ensemble method. The dependence of hydration shell size on interionic distance has been calculated by the method of compensation potential. The transition between the states of a contact (CIP) and a solvent-separated ion pair (SSIP) has been reproduced under the conditions of a nanopore. The influence of the pore increases with the hydration shell size and leads to the stabilization of the SSIP states, which are only conditionally stable in bulk water vapor. © 2016, Pleiades Publishing, Ltd.


Sheskin E.B.,JSC STS UPS | Evdokunin G.A.,Peter The Great St Petersburg Polytechnical University
Power Technology and Engineering | Year: 2016

The problem of disconnecting high-voltage cable lines with shunt reactors by SF6 circuit breakers is discussed. In these schemes it is possible to have a significant aperiodic component of the circuit breaker current that can prevent opening of the breaker. The authors propose methods for application to cable transmission lines which they believe will be optimal for ensuring normal disconnects. © 2016, Springer Science+Business Media New York.


Shevkunov S.V.,Peter The Great St Petersburg Polytechnical University
Russian Journal of Physical Chemistry A | Year: 2016

The hydration of a single-charged chloride anion Cl- in a model plane nanopore with structureless hydrophilic walls in water vapor at room temperature is simulated using the Monte Carlo method. It is established that the adsorption of a fraction of associate molecules Cl-(H2O)N on the walls enhances its thermodynamic stability and simulates the hydration of the ion at low vapor pressures. It is shown that a second stability crisis forms on the curve of the hydration work function in the mode of weak wall hydrophilicity. © 2016, Pleiades Publishing, Ltd.

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