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1.
N. G. Kanev 《Acoustical Physics》2006,52(5):571-575
Effect of errors of different origin on the efficiency of sound absorption by a local active absorber is investigated. Degradation of the efficiency of absorption because of the errors is shown to be minimal in the case when the controller does not detect the field of the secondary radiator. Estimates of admissible errors are presented. Several active absorber configurations in which the radiator does not affect the receiver are considered. 相似文献
2.
3.
Nikolay Tyutyulkov Ivo Kanev Oskar Polansky Jürgen Fabian 《Theoretical chemistry accounts》1977,46(3):191-203
The analysis of experimental data for singlet transitions (E
n) of even polyenes (I), cations (II) and anions (III) of odd polyenes show that for infinite chains E
(I)/E
(II)=E
(I)/E
(III) = 2:1. It is shown that the energy gap is equal for the three systems. In cases (II) and (III) there is a level (NBMO) in the gap which is vacant in (II) and occupied in (III). That is why the first optical transition in (II) and (III) depends on the semiwidth of the gap. 相似文献
4.
Starikov FA Kochemasov GG Kulikov SM Manachinsky AN Maslov NV Ogorodnikov AV Sukharev SA Aksenov VP Izmailov IV Kanev FY Atuchin VV Soldatenkov IS 《Optics letters》2007,32(16):2291-2293
Reconstruction the phase front of a vortex laser beam is conducted by use of a Hartmann-Shack wavefront sensor. The vortex beam in the form of the Laguerre-Gaussian LG(0)(1) mode is generated with the help of a spiral phase plate. The new reconstruction technique based on measured wavefront gradients allows one to restore the singular phase surface with good accuracy, whereas the conventional least-squares approach fails. 相似文献
5.
Vassil Kanev 《Journal of Mathematical Sciences》1999,94(1):1114-1125
It is proved that the chordal variety of the Veronese variety
is projectively normal, arithmetically caulay, and its homogeneous ideal is generated by the 3×3 minors of two catalecticant
matrices. Results are generalized to the catalecticant varieties Gor≤(T) witht
1=2.
Translated from Itogi Nauki i Tekhniki, Seriya Sovremennaya Matematika i Ee Prilozheniya. Tematicheskie Obzory. Vol. 56. Algebraic
Geometry-9, 1998. 相似文献
6.
Valerii P. Aksenov Igor V. Izmailov Feodor Yu. Kanev Boris N. Poizner 《Optics Communications》2012,285(6):905-928
The principle of determining the topological charge of an optical vortex is suggested based on measuring the light field intensity and designing the corresponding detector. A mathematical model of the performance of the detector of topological vortex charge is presented. Results of numerical experiments imitating the vortex recognition in the presence of turbulence or (amplitude or phase) noise in registered radiation as well as of the displacement of the optical beam source and detector axes are presented. Principles are formulated of designing the position finder for an optical vortex (that is, the detector of vortex coordinates) that allows us to consider its realization in the form of mathematical and numerical model. Conditions of reliable operation of the vortex detector and singular optical communication line constructed on its basis are estimated. Dependencies of the probability of error in data transfer on the turbulence intensity, photodetector noise amplitude, and displacement of the optical axes are investigated for different coding algorithms (absolute and differential with fixed or adaptive threshold). The data of modeling confirm the results of analytical calculations. 相似文献
7.
A sound absorber in a narrow waveguide is considered. The absorber consists of one monopole and one dipole resonator placed in a narrow pipe. The optimum parameters of the resonators that provide for the maximum absorption of acoustic power are determined. Results of an experimental study of a two-resonator absorbing system are presented. A 95% absorption is achieved. 相似文献
8.
A method of active sound control by a local device, namely, an active resonator that provides a resonance absorption or scattering of sound in a broad frequency band, is proposed. The active resonator is modeled as a sound source with an acoustoelectric feedback, which allows the correction of its motion depending on the sound field measured in the vicinity of the resonator. The performance of the method is demonstrated by two examples. 相似文献
9.
N. G. Kanev 《Acoustical Physics》2016,62(1):108-111
The paper presents acoustic measurement results for two concert halls in which nonexponential sound decay is observed. Quantitative estimates are given for how the obtained decay laws differ from exponential. Problems are discussed that arise when using reverberation time to assess the quality of room acoustics with nonexponential sound decay. 相似文献
10.
N. G. Kanev 《Acoustical Physics》2012,58(5):603-609
The problem of sound decay in a rectangular room is considered for the case of a room with walls the acoustic properties of which are described by the impedance, which implies a dependence of the absorption coefficient on the angle of incidence of sound waves. The ray approximation is used to determine the sound decay laws for different distributions of wall absorption. It is shown that, in a room with impedance walls, the sound decay is slower than in the conventional reverberation model, in which the wall absorption coefficient is independent of the angle of incidence. The problem is also solved in the wave approximation to determine the decay law for a preset frequency band. 相似文献