4,218 research outputs found
Singular perturbations of Volterra equations with periodic nonlinearities: Stability and oscillatory properties
No full textSingularly perturbed integro-differential Volterra equations with MIMO periodic nonlinearities are considered, which describe synchronization circuits (such as phase- and frequency-locked loops) and many other “pendulum-like” systems. Similar to the usual pendulum equation, such systems are typically featured by infinite sequences of equilibria points, and none of which can be globally asymptotically stable. A natural extension of the global asymptotic stability is the gradient-like behavior, that is, convergence of any solution to one of the equilibria. In this paper, we offer an efficient frequency-domain criterion for gradientlike behavior. This criterion is not only applicable to a broad class of infinite-dimensional systems with periodic nonlinearities, but in fact ensures the equilibria set stability under singular perturbation. In particular, the proposed criterion guarantees the absence of periodic solutions that are considered to be undesirable in synchronization systems. In this paper we also discuss a relaxed version of this criterion, which guarantees the absence of “high-frequency” periodic solutions, whose frequencies lie beyond a certain bounded interval.Accepted Author ManuscriptTeam Tamas Keviczk
Volterra Equations with Periodic Nonlinearities: Multistability, Oscillations and Cycle Slipping
No full textIn this paper, systems of nonlinear integro-differential Volterra equations are examined that can be represented as feedback interconnections of linear time-invariant block and periodic nonlinearities. The interest in such systems is motivated by their numerous applications in mechanical, electrical and communication engineering; examples include, but are not limited to, models of phase-locked loops, pendulum-like mechanical systems, coupled vibrational units and electric machines. Systems with periodic nonlinearities are usually featured by multistability and have infinite sequences of (locally) stable and unstable equilibria; their trajectories may exhibit nontrivial (e.g. chaotic) behavior. We offer frequency-domain criteria, ensuring convergence of any solution to one of the equilibria points, and this property is referred to as the gradient-like behavior and corresponds to phase locking in synchronization systems. Although it is hard to find explicitly the equilibrium, attracting a given trajectory, we give a constructive estimate for the distance between this limit equilibrium and the initial condition. The relevant estimates are closely related to the analysis of cycle slipping in synchronization systems. In the case where the criterion of gradient-type behavior fails, a natural question arises-which nonconverging solutions may exist in the system and, in particular, how many periodic solutions it has. We show that a relaxation of the frequency-domain convergence criterion ensures the absence of high-frequency periodic orbits. The results obtained in the paper are based on the method of integral quadratic constraints that has arisen in absolute stability theory and stems from Popov's techniques of "a priori integral indices". We illustrate the analytic results by numerical simulations.</p
Dichotomy and stability of disturbed systems with periodic nonlinearities
No full textSystems that can be decomposed as feedback interconnections of stable linear blocks and periodic nonlinearities arise in many physical and engineering applications. The relevant models e.g. describe oscillations of a viscously damped pendulum, synchronization circuits (phase, frequency and delay locked loops) and networks of coupled power generators. A system with periodic nonlinearities usually has multiple equilibria (some of them being locally unstable). Many tools of classical stability and control theories fail to cope with such systems. One of the efficient methods, elaborated to deal with periodic nonlinearities, stems from the celebrated Popov method of 'integral indices', or integral quadratic constraints; this method leads, in particular, to frequency-domain criteria of the solutions' convergence, or, equivalently, global stability of the equilibria set. In this paper, we further develop Popov's method, addressing the problem of robustness of the convergence property against external disturbances that do not oscillate at infinity (allowing the system to have equilibria points). Will the forced solutions also converge to one of the equilibria points of the disturbed system? In this paper, a criterion for this type of robustness is offered.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Tamas Keviczk
Self-synchronization of unbalanced rotors and the swing equation
No full textWe consider a problem of self-synchronization in a system of vibro-exciters (rotors) installed on a common oscillating platform. This problem was studied by I.I. Blekhman and later by L. Sperling. Extending their approach, we derive the equations for a system of n rotors and show that, separating the slow and fast motions, the “slow” dynamics of this systems reduces to a special case of a so-called swing equation that is well studied in theory of power networks. On the other hand, the system may be considered as “pendulum-like” system with multidimensional periodic nonlinearities. Using the theory of such systems developed in our previous works, we derive an analytic criteria for synchronization of two rotors. Unlike synchronization criteria available in mechanical literature, our criterion ensures global convergence of every trajectory to the synchronous manifold
Astronomy Letters, V. 31, I. 03
No full textAstronomy Letters -- March 2005
Volume 31, Issue 3, pp. 147-219
Constraints on the Photon Charge from Observations of Extragalactic Sources
V. V. Kobychev and S. B. Popov
pp. 147-151 Full Text: PDF (150 kB)
Global Properties of Nearby Galaxies in Various Environments
I. D. Karachentsev and A. V. Kasparova
pp. 152-159 Full Text: PDF (356 kB)
The Gas Content in Galactic Disks: Correlation with Kinematics
A. V. Zasov and A. A. Smirnova
pp. 160-170 Full Text: PDF (366 kB)
Parameters of the Spiral Structure of the Galaxy from Data on Open Star Clusters
M. E. Popova and A. V. Loktin
pp. 171-178 Full Text: PDF (217 kB)
Interaction of the Supernova Remnant HB3 with the Ambient Interstellar Gas
I. V. Gosachinskii
pp. 179-185 Full Text: PDF (254 kB)
Strong Cosmic-Ray Scattering in an Anisotropic Random Magnetic Field
Yu. P. Mel'nikov and I. N. Toptygin
pp. 186-193 Full Text: PDF (192 kB)
The SCORPIO Universal Focal Reducer of the 6-m Telescope
V. L. Afanasiev and A. V. Moiseev
pp. 194-204 Full Text: PDF (476 kB)
Moments of Inertia and the Chandlerian Period for Two- and Three-Layer Models of the Galilean Satellite Io
V. N. Zharkov and A. L. Sobisevich
pp. 205-212 Full Text: PDF (198 kB)
Analysis of the Neighborhood of the 2 : 1 Resonance in the Equal-Mass Three-Body Problem
A. I. Martynova, V. V. Orlov, and L. L. Sokolov
pp. 213-219 Full Text: PDF (310 kB)Archived web conten
STABILITY CONSTANTS OF L-ASPARAGINE AND L-LEUCINE COMPLEXES WITH SOME LANTHANIDE IN AQUEOUS SOLUTIONS AT 298.15 K
No full textLanthanides have a high affinity toward ligands containing donor oxygen atoms, especially amino acids and complexons. The study of the processes of complexation of amino acids with f-element cations provides valuable information for solving problems of supramolecular chemistry, molecular recognition and chiral sensitivity of biological substrates. As a rule, f-elements are not components of biopolymers, but they are spectral label probes, which are important in the bioinorganic chemistry of metals. Quantitative estimation of the stability of complexes is necessary, first of all, to search for an internal connection between the constants themselves and then to find correlations between the stability of complexes and the properties of the complexing agent, the ligand, and the system as a whole. Such correlation dependencies make it possible to calculate a priori, or at least estimate the stability constants of new complexes, and also to better understand the influence of the nature of the chemical bond and the properties of the system as a whole on the formation and stability of complex compounds. In the present work, the complexation of neodymium, lanthanum with L-asparaginat ion and samarium, cerium with L-leucinat ion at 298.15 K and ionic strength values of 0.5 mol/l was studied by potentiometric titration and the stability constants of the complexes formed were determined. The values of the stability constants found allow us to perform rigorous thermodynamic calculations of the equilibria of these amino acids in salt solutions. The data obtained, in particular, can be used to reliably interpret the results of calorimetric studies of the complexation of lanthanides with the participation of the studied amino acids.Forcitation:Lytkin A.I., Chernyavskaya N.V., Smirnova D.K. Stability constants of L-asparagine and L-leucine complexes with some lanthanide in aqueous solutions at 298.15 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 37-41</jats:p
Astronomy Reports V. 45, I. 10
No full textAstronomy Reports -- October 2001
Volume 45, Issue 10, pp. 751-840
The Angular-Momentum Distribution in Axisymmetrical Galaxies
B. P. Kondratyev
pp. 751-754 Full Text: PDF (135 kB)
An Active Galactic Nucleus as a Massive Coaxial Pulsar: A Massive Central Object with a Keplerian Accretion Disk and Twisted MHD Jet
Ya. N. Istomin and B. V. Komberg
pp. 755-758 Full Text: PDF (128 kB)
Image Reconstruction for the Einstein Cross Gravitational Lens QSO 2237+0305
V. A. Belokurov, E. V. Shimanovskaya, M. V. Sazhin, A. G. Yagola, B. P. Artamonov, V. N. Shalyapin, and I. Khamitov
pp. 759-768 Full Text: PDF (317 kB)
Arc-Shaped and Spheroidal Stellar Complexes
Yu. N. Efremov
pp. 769-783 Full Text: PDF (702 kB)
The Chemical Compositions and Surface Structures of Two roAp Stars with Lithium Spots (HD 83368 and HD 60435)
A. V. Shavrina, N. S. Polosukhina, J. Zverko, V. Khalak, V. V. Tsymbal, and J. Ziznovský
pp. 784-796 Full Text: PDF (417 kB)
Parameters of the Dust Envelope of the Symbiotic Star CH Cygni
M. B. Bogdanov and O. G. Taranova
pp. 797-803 Full Text: PDF (243 kB)
Six-Day Modulation of the Quiescent Radio Emission of SS 433
S. A. Trushkin, N. N. Bursov, and Yu. V. Smirnova
pp. 804-815 Full Text: PDF (516 kB)
Generation of Large-Scale Magnetic Fields in Young Solar-Type Stars
L. L. Kitchatinov
pp. 816-823 Full Text: PDF (225 kB)
Parameters of the Turbulent Magnetic Field in the Solar Photosphere: Power Spectrum of the Line-of-Sight Field
V. I. Abramenko, V. B. Yurchyshyn, H. Wang, and P. R. Goode
pp. 824-833 Full Text: PDF (294 kB)
The Three-Dimensional Structure of the Solar Corona
S. L. Koutchmy, V. L. Merzlyakov, and M. M. Molodenskii
pp. 834-840 Full Text: PDF (643 kB)Archived web conten
Astronomy Reports V. 44, I. 07
No full textAstronomy Reports -- July 2000
Volume 44, Issue 7, pp. 421-493
Interstellar Scintillation of the Radio Source Associated with the Gamma-Ray Burst of May 8, 1997
T. V. Smirnova and V. I. Shishov
pp. 421-425 Full Text: PDF (63 kB)
Physical Conditions in Photodissociation Regions from Observations of Carbon Radio Recombination Lines and IR Fine-Structure Lines of CII and OI
R. L. Sorochenko and A. P. Tsivilev
pp. 426-435 Full Text: PDF (124 kB)
Flux Densities of 235 Pulsars at 102.5 MHz
V. M. Malofeev, O. I. Malov, and N. V. Shchegoleva
pp. 436-445 Full Text: PDF (123 kB)
Light-Curve Synthesis for Close Binaries: Elliptical Disk around a White Dwarf
T. S. Khruzina
pp. 446-459 Full Text: PDF (260 kB)
Multicolor Photometry of CH Cygni in 1978–1998
O. G. Taranova and V. I. Shenavrin
pp. 460-473 Full Text: PDF (296 kB)
Precision Astrometry with Schmidt Telescopes
K. V. Kuimov, F. D. Sorokin, A. V. Kuz'min, and N. T. Barusheva
pp. 474-480 Full Text: PDF (200 kB)
Investigation of Magnetic Fields in Solar Active Regions
S. I. Gopasyuk, O. S. Gopasyuk, I. P. Zalesov, D. V. Karkach, and V. V. Svistel'nikov
pp. 481-486 Full Text: PDF (108 kB)
Longitude and Latitude Structure of the Polar Activity of the Sun in the 21st Cycle
V. P. Mikhailutsa and V. V. Makarova
pp. 487-493 Full Text: PDF (337 kB)Archived web conten
Plasma Physics Reports V. 27, I. 12
No full textdc.description[en_US]Plasma Physics Reports -- December 2001
Volume 27, Issue 12, pp. 1001-1088
TOKAMAKS
Effect of the Radial Electric Field on Lower Hybrid Plasma Heating in the FT-2 Tokamak
S. I. Lashkul, V. N. Budnikov, E. O. Vekshina, V. V. D'yachenko, V. B. Ermolaev, L. A. Esipov, E. R. Its, M. Yu. Kantor, D. V. Kuprienko, A. Yu. Popov, and S. V. Shatalin
pp. 1001-1010 Full Text: PDF (159 kB)
STELLARATORS
One Possible Way to Affect the Impurity Influx into the Plasma of a Stellarator with Poloidal Slits in the Vacuum Wall
D. L. Grekov
pp. 1011-1016 Full Text: PDF (94 kB)
INERTIAL CONFINEMENT FUSION
Fast Ignitor Concept with Light Ions
V. Yu. Bychenkov, W. Rozmus, A. Maksimchuk, D. Umstadter, and C. E. Capjack
pp. 1017-1020 Full Text: PDF (61 kB)
NONIDEAL PLASMA
Mechanism for the Disappearance of Spectral Lines in a Nonideal Plasma
V. K. Gryaznov, O. B. Denisov, M. I. Kulish, V. B. Mintsev, N. Yu. Orlov, and V. E. Fortov
pp. 1021-1024 Full Text: PDF (51 kB)
Phase Transition in Superdense Hydrogen and Deuterium
M. Bonitz, I. A. Mulenko, E. N. Oleynikova, V. S. Filinov, V. E. Fortov, and A. L. Khomkin
pp. 1025-1031 Full Text: PDF (100 kB)
ELEMENTARY PROCESSES IN PLASMA
Relation between Electron Exchange and Nuclear Vibrations in the H + 2 + H + 2 --> H + 3 + p Exothermic Ion���Molecular Reaction
V. A. Belyaev, M. M. Dubrovin, A. A. Terent'ev, A. E. Trenin, and G. V. Sholin
pp. 1032-1038 Full Text: PDF (88 kB)
PLASMA DYNAMICS
Study of the Plasma in a Preformed Z-pinch Constriction
Yu. L. Bakshaev, P. I. Blinov, V. V. Vikhrev, E. M. Gordeev, S. A. Dan'ko, V. D. Korolev, S. F. Medovshchikov, S. L. Nedoseev, E. A. Smirnova, V. I. Tumanov, A. S. Chernenko, and A. Yu. Shashkov
pp. 1039-1047 Full Text: PDF (198 kB)
Acceleration of Dense Electron Bunches at the Front of a High-Power Electromagnetic Wave
A. S. Il'in, V. V. Kulagin, and V. A. Cherepenin
pp. 1048-1056 Full Text: PDF (134 kB)
LOW-TEMPERATURE PLASMA
Streamer Breakdown of Long Gas Gaps
N. L. Aleksandrov and E. M. Bazelyan
pp. 1057-1078 Full Text: PDF (412 kB)
Electron Temperature in a Decaying Molecular Nitrogen Plasma in the Presence of Weak Electric Fields
N. A. Gorbunov, N. B. Kolokolov, and F. E. Latyshev
pp. 1079-1088 Full Text: PDF (184 kB)dc.description.contributor[en_US]dc.description.contributor[en_US
Plasma Physics Reports V. 27, I. 12
No full textPlasma Physics Reports -- December 2001
Volume 27, Issue 12, pp. 1001-1088
TOKAMAKS
Effect of the Radial Electric Field on Lower Hybrid Plasma Heating in the FT-2 Tokamak
S. I. Lashkul, V. N. Budnikov, E. O. Vekshina, V. V. D'yachenko, V. B. Ermolaev, L. A. Esipov, E. R. Its, M. Yu. Kantor, D. V. Kuprienko, A. Yu. Popov, and S. V. Shatalin
pp. 1001-1010 Full Text: PDF (159 kB)
STELLARATORS
One Possible Way to Affect the Impurity Influx into the Plasma of a Stellarator with Poloidal Slits in the Vacuum Wall
D. L. Grekov
pp. 1011-1016 Full Text: PDF (94 kB)
INERTIAL CONFINEMENT FUSION
Fast Ignitor Concept with Light Ions
V. Yu. Bychenkov, W. Rozmus, A. Maksimchuk, D. Umstadter, and C. E. Capjack
pp. 1017-1020 Full Text: PDF (61 kB)
NONIDEAL PLASMA
Mechanism for the Disappearance of Spectral Lines in a Nonideal Plasma
V. K. Gryaznov, O. B. Denisov, M. I. Kulish, V. B. Mintsev, N. Yu. Orlov, and V. E. Fortov
pp. 1021-1024 Full Text: PDF (51 kB)
Phase Transition in Superdense Hydrogen and Deuterium
M. Bonitz, I. A. Mulenko, E. N. Oleynikova, V. S. Filinov, V. E. Fortov, and A. L. Khomkin
pp. 1025-1031 Full Text: PDF (100 kB)
ELEMENTARY PROCESSES IN PLASMA
Relation between Electron Exchange and Nuclear Vibrations in the H + 2 + H + 2 --> H + 3 + p Exothermic Ion–Molecular Reaction
V. A. Belyaev, M. M. Dubrovin, A. A. Terent'ev, A. E. Trenin, and G. V. Sholin
pp. 1032-1038 Full Text: PDF (88 kB)
PLASMA DYNAMICS
Study of the Plasma in a Preformed Z-pinch Constriction
Yu. L. Bakshaev, P. I. Blinov, V. V. Vikhrev, E. M. Gordeev, S. A. Dan'ko, V. D. Korolev, S. F. Medovshchikov, S. L. Nedoseev, E. A. Smirnova, V. I. Tumanov, A. S. Chernenko, and A. Yu. Shashkov
pp. 1039-1047 Full Text: PDF (198 kB)
Acceleration of Dense Electron Bunches at the Front of a High-Power Electromagnetic Wave
A. S. Il'in, V. V. Kulagin, and V. A. Cherepenin
pp. 1048-1056 Full Text: PDF (134 kB)
LOW-TEMPERATURE PLASMA
Streamer Breakdown of Long Gas Gaps
N. L. Aleksandrov and E. M. Bazelyan
pp. 1057-1078 Full Text: PDF (412 kB)
Electron Temperature in a Decaying Molecular Nitrogen Plasma in the Presence of Weak Electric Fields
N. A. Gorbunov, N. B. Kolokolov, and F. E. Latyshev
pp. 1079-1088 Full Text: PDF (184 kB)Archived web conten
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