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Machac J.,Czech Technical University | Polivka M.,Czech Technical University | Zemlyakov K.,St Petersburg Electrotechnical University
IEEE Transactions on Antennas and Propagation | Year: 2013

This communication presents the results of an investigation of a new version of a leaky wave antenna designed on a CRLH substrate integrated waveguide. The antenna operates in two frequency bands and its main beam can be steered from backward to forward direction by changing the frequency. The antenna structure is planar and can be fabricated by a standard PCB technology, so it is suitable for mass production. An efficient method for determining the complex dispersion characteristic of periodic 1D structure is proposed. © 1963-2012 IEEE. Source

Demidovich V.B.,St Petersburg Electrotechnical University | Rastvorova I.I.,St. Petersburg State Mining Institute
Russian Electrical Engineering | Year: 2014

A combined method for numerical computation of the electromagnetic field in induction-heating systems is proposed and used. The method consists in a combination of methods of integral equations for the computation of the electromagnetic field in the area outside the load and methods of finite elements or finite differences for the computation of the electromagnetic field inside the load. A method of simulation of electrotechnical systems with simultaneous solving of circuit and field problems is proposed based on this method. Using the example of induction-heating devices, an external problem associated with the computation of circuit inductors, power supplies, and balancing capacitors and an internal problem related to the computation of the electromagnetic field and internal heat sources inside the load are formulated. The simulation of induction heaters is considered taking into account features of thyristor frequency converters with a parallel inverter. © 2014, Allerton Press, Inc. Source

Mukhin N.V.,St Petersburg Electrotechnical University
Glass Physics and Chemistry | Year: 2014

A one-dimensional model describing the diffusion of intrinsic defects in lead zirconate titanate (LZT) films of nonstoichiometric composition during their high-temperature treatment is proposed. The model includes the diffusion of vacancies by lead and oxygen, the formation and decay of their associates, interaction with extensive defects (dislocations in LZT films and the near-surface layer), interstitial inclusions, and LZT film contact with air leading to lead oxide evaporation from LZT film and its saturation by oxygen. The dependences of LZT film composition on the temperature and time of treatment are calculated. The possibility the concentration's oversaturation by lead in a near-surface layer of LZT film, which can lead to the release of lead oxide, is shown. © 2014 Pleiades Publishing, Ltd. Source

Belorus A.O.,St Petersburg Electrotechnical University | Maraeva E.V.,St Petersburg Electrotechnical University | Spivak Y.M.,St Petersburg Electrotechnical University | Moshnikov V.A.,Polytechnic University of Mozambique
Journal of Physics: Conference Series | Year: 2015

Gas adsorption and capillary condensation phenomena were studied in powders of porous silicon with different doping levels of the silicon substrate of n-type conductivity in various conditions. Specific surface area and the rated pore size distribution were determined for porous silicon with complex texture by the capillary condensation method. It is shown that the samples obtained in silicon with a higher doping level have a higher value of specific surface area. © Published under licence by IOP Publishing Ltd. Source

Tong W.,Colorado State University | Tong W.,Chinese Academy of Sciences | Wu M.,Colorado State University | Carr L.D.,Colorado School of Mines | Kalinikos B.A.,St Petersburg Electrotechnical University
Physical Review Letters | Year: 2010

This Letter reports experimental results on random temporal dark solitons. One excites an incoherent large-amplitude propagating spin-wave packet in a ferromagnetic film strip with a repulsive, instantaneous nonlinearity. One then observes the random formation of dark solitons from this wave packet. The solitons appear randomly in time and in position relative to the entire wave packet. They can be gray or black. In spite of the randomness of the initial wave packets and the random formation processes, the solitons show signatures that are found for conventional coherent dark solitons. © 2010 The American Physical Society. Source

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