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Russian Acoustical Society:
ASA scholars 2001
Students
 
  1. Evgeniy Vilkov
    Vilkov
    Place of Work: Ul'yanovsk Branch of Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Goncharova 48, 432011, Ui'yanovsk, Russia
    Date of birth: 29.03.1975
    Education: higher, graduated from the Physico-technical faculty of Ulyanovsk State University in 1997 by speciality "solid-state physics" with degree "Engineer-physicist. 1997-2001, Post-graduate course, Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Ph.D. Thesis: "Magnetoelastic shear waves and magnetostatic waves transformation on a moving domain boundary in a ferromagnetic crystal".
    Position: Research Scientist.
    Research title: Magnetoelastic shear waves transformation on a moving domain boundary in a ferromagnetic crystal.
    Main results:
    The aim of investigation is the study of interaction of a shear magnetoelastic waves with moving domain boundary in a ferromagnetic crystal. The scientific novelty of investigation is stated in the following points.
    1. The possibility of the existence and the properties of a noncollinear shear surface wave on a moving domain boundary in a ferromagnet was considered. It is shown that the motion of a domain wall produces the directive action on the wave normal of the shear surface wave and changes significantly its spectrum in the case of direct vawe propagation in the frequency band below the ferromagnetic resonance corresponding to the scattering field [1-2].
    2. The energetic estimate of surface wave transformation by the motion of domain boundary is presented. Changes of wave spectrum influenced by the boundary motion are compared with variations of energy of elastic and magnetic subsystem. The velocity of moving boundary being rised, the positive increment of energy density is marked [3].
    3. The boundary-value problem of the interaction of a plane monochromatic shear wave with a moving Bloch wall in an iron garnet crystal is solved. For a shear wave incident on the domain wall, the possibility of the reflectionless birefringence is demonstrated [4].
    4. The role of the nonlinearty of the spin subsystem under the reflection of the plane monochromatic shear wave with little pump power by the approaching domain wall in a ferromagnetic crystal was estimated [5].
    Main references:
    1. E. A. Vilkov, V. G. Shavrov, N. S. Shevyakhov, "A noncollinear shear surface wave on a moving domain boundary in a ferromagnet", J. Technical Physics Letters. Vol. 27. No 9. pp. 728-730. (2001). (Translated from Pi'sma v Zhurnal Tekhnicheskoi Fiziki. Vol. 27. No 17. 2001. pp. 40-45).
    2. E. A. Vilkov, V. G. Shavrov, N. S. Shevyakhov, "Shear surface wave on a moving bloch wall", J. Radiophysics and Electronics. Vol 44. No 8. pp. 656-667. (2001). (Translated from Izvestiya Vysshikh Ucebnych Zavedenii. Radiofizika. Vol.44. 2001. No 8. pp. 712-724).
    3. E. A. Vilkov, V. G. Shavrov, N. S. Shevyakhov, "Efficiency of surface wave transformation by the motion of domain boundary", J. Zhurnal Tekhnicheskoi Fiziki. V®l. 73. No 3. pp. 80-86 (2003).
    4. E. A. Vilkov, V. G. Shavrov, N. S. Shevyakhov, "Interaction of a shear wave with a moving domain wall in an iron garnet crystal" (reviews). J. Acoustical Physics. Vol. 47. No 2. pp. 160-168. (2001) (Translated from Akustichekii Zhurnal. Vol. 47. No 2. 2001. pp. 200-209).
    5. E. A. Vilkov, V. G. Shavrov, N. S. Shevyakhov, "On the interaction of a shear wave with a moving domain wall in a nonlinear response of the spin subsystem", J. Physics of the Solid State. Vol. 42. No 6. pp. 1081-1086. (2000). (Translated from Fisika Tverdogo Tela. Vol. 42. No 6. 2000. pp. 1049-1054).
    Technical Area: Physical acoustics
    PACS codes: 43.35.Pt, 43.35.Rw
  2. Maksim Gureyev
    Place of Work: Department of General and Aplayed Physics, Moscow Institute of Physics and Technology, 9 Institutskii, Dolgoprudny, Moscow reg., Russia
    Date of birth: 20.06.1981
    Research title: Waves in an acoustical resonator of varying cross-sectional area.
    Main results:
    Waves in an acoustical resonator of varying cross-sectional area was investigated. Experemental stand for reserch of resonator of varying cross-sectional area was created. The resonator was placed on vibrator. The sonic presure in narrow part of resonator was measured at different amplitude of acceleration up to 100 m/s2. Some types of resonator were experementally investigated. It was shown that change of the form of the resonator it is possible to achieve increase of amplitude of pressure in some times at constant amplitude of acceleration. Essential dependence of resonant frequency on the form of a structure of the resonator was revealed. For the decision of a problem on distribution of sound waves in the resonator of variable section two variants of VKB method were used. Conditions of their applicability were considered. These variants were comparisoned. It is shown, that depending on a structure of the resonator this or that method is more preferable. The question on a way of excitation of a wave in the resonator was considered.
  3. Nickolay Kanev
    Kanev
    Place of Work: Department of General and Applied Physics, Moscow Institute of Physics and Techology, 9 Institutskii, Dolgoprudny, Moscow reg., Russia
    Date of birth: 31.08.1980
    Research title: Broadening of frequency band of resonance dipole scatterer by means of feedback control.
    Main results:
    It is demonstrated both theoretically and experimentally that a dipole resonator is so effective sound scatterer as a monopole resonator (for example Helmholtz resonator). The passive dipole resonator located in a duct reflects fully the primary wave if the wave frequency equals to the resonance frequency of scatterer. In order to increase the effective scattering frequency band of passive dipole one can use an electrical feedback, in other words to make an active dipole. A command signal is taken from sensor situated close to scatterer. The feedback scheme (between source and sensor) is a simple analog frequency filter. The sensor in active dipole is a dipole too. So the active dipole may by used for active noise control. It is possible entirely blocking of narrow waveguide in wide frequency band. This system with feedback is stable for all frequencies. It was designed the feedback filter with necessary gain-phase-frequency characteristic. The active monopole and the active dipole are equally effective for scattering and absorption in a duct. If the source is used as an absorber, it can absorb only one half of the external sound power, while this power can be fully absorbed by two sources. One of them is a dipole and other is a monopole. The active dipole can be applied to produce such structures as an active controlled window or an active noise barrier. Analysis shows the active dipole is more convenient and efficient in comparison with monopole. Also a combination of monopoles and dipoles is possible.
    Main references:
    1. Dipole resonant sound scatterer. Acoustical Physics, Vol. 49, No. 3. 2003.
    2. Shore Noise in a Calm Sea, Acoustical Physics, Vol. 48, No. 6, 2002, pp. 741-743.
  4. Sergey Kovalev
    Kovalev
    Place of Work: Nizhny Novgorod Mechanical Engineering Research Institute Russian Academy of Science
    Date of birth: 08.05.1974
    Education: Radio physical Department of Nizhny Novgorod Government University, PhD Student at Nizhny Novgorod Mechanical Engineering Research Institute Russian Academy of Science
    Research title: Nonlinear Magnetoelastic Waves in the Media with Coupled Stresses.
    Main results:
    The influence of microstructure in the problems of magneto elasticity have been Studied. A number of nonclassical problems of momentum theory of elasticity was considered in nonlinear approximation, in particular: stationary magneto elastic waves in an ideally conducting solid with microstructure were studied; the correlation between wave parameters and the intensity of a magnetic field was found; the influence of finite conductivity of materials to wave processes was considered; the effect of self-modulation of regular and noise shear magneto elastic waves in a medium with microstructure was researched, dependence of parameters of stationary waves envelope on the magnetic field was found. The obtained results showed that it is possible to control dispersing, dissipative and nonlinear properties of medium with microstructure with the help of a magnetic field.
    Main references:
    1. Erofeyev V., Kazhaev V. and Kovalev S. Longitudinal Magneto-Elastic Waves in Solids with Microstructure, IUTAM Sympozium on Mechanical and ... Kluver Academic Publishes. 2001. PP.149-158
    2. Erofeyev V. and Kovalev S. Self-Modulation of Quasi-Harmonic Shear Magnetoelastic Waves //Proc. IUTAM Symposium 99/4, Mechanical and Electromagnrtic Waves in Structured Media,1999, P 28-29.
    3. Erofeyev V. and Kovalev S. Microstructured Solids: Non-linear Models and Analysis of Magneto-Elastic Wave Processes // Material Instabilities in Solids, Edited by R. De Borst and E. van der Giessen; John Wiley & Sons Ltd. 1998, P. 55-64.
    4. Erofeyev V. and Kovalev S. Self-Modulation of Quasi-Periodic Shear Magnetoelastic Waves //Acoustics Letters, Edited by John C. Scott, V.20, ¹12, June 1997, P 266-268.
    5. V.I. Erofeyev and S.I. Kovalev Self-modulation of Quasi-periodic Magnetoelastic Waves //Acoustics at the Threshold of the XXIst Century, VI Session of the Russian Acoustical Society, Ì., 1997, p. 315-318.
  5. Dmitry Smagin
    Smagin
    Place of Work: N. Andreyev Acoustics Institute, Shvernika 4, 117036 Moscow
    Research title: Active noise control systems.
    Main results:
    The research purpose is designing of active noise control (ANC) systems. This research includes study of acoustic properties of control object, analysis and synthesis of regulators, control algorithms realization, development and launching of such systems on the computers' technologies basis. In last experiment the multiply connected multidimensional broadband ANC system with reference signal was investigated. As control object single-mode air duct was used, with mounted compensatory loudspeaker and microphones near both ends of it. For better system observation the position of control microphones were selected far from a node of first several fundamental oscillations. The disturbance signal (with frequency range 10…500 Hz and approximate uniform distribution) feeds the loudspeaker mounted at the central part of the duct. The reference signal was taken from the excitation generator. During experimental tests the efficiency of noise attenuation was from 10 dB up to 20 dB (on the first resonance of air duct, nearby frequency 110 Hz) in a range of frequencies from 40 Hz up to 300 Hz. The frequency of quantization was 5 kHz. The obtained result can be used for vibration control too (e.g., at engine supports). Now the similar system can be applied for attenuation broadband noise in apertures, creation of silence zones and so on. The research is conducted by designing broadband ANC systems which don't require a reference signal. These systems will allow expanded range of application and provide cost reduction. A problem of stability of such system will be solved partially by using global optimization.
    Technical area: Noise and noise control.