Kyiv University

Kiev, Ukraine

Kyiv University

Kiev, Ukraine
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Govor E.V.,Kyiv University | Lysenko A.B.,Kyiv University | Quinonero D.,University of the Balearic Islands | Rusanov E.B.,Institute of Organic Chemistry | And 6 more authors.
Chemical Communications | Year: 2011

Chloride-centered hexanuclear hydroxopyrazolate reveals potential as a receptor of halomethane and halometallate species and as a molecular building block for coordination polymers. © 2011 The Royal Society of Chemistry.

Babaev A.E.,Ukrainian Academy of Sciences | Babaev A.A.,Kyiv University | Yanchevskiy I.V.,Kharkiv National Automobile and Highway University
Journal of the Acoustical Society of America | Year: 2010

The problem of nonstationary wave radiation in an infinitely long thick-wall piezoelectric cylinder in fluid medium is considered. The influence of an oscillating circuit with lumped parameters on characteristics of transient process is taken into consideration. Problem formulation is executed within the forced electrostatic theory, acoustic approximations, and quasistatic theory for electric circuit. The solution method is based on the integral Laplace transform in time. This allows analytically reducing the problem to solving a system of Volterra integral equations with retarded arguments. The numerical results of calculations are presented and analyzed. © 2010 Acoustical Society of America.

Domasevitch K.V.,Kyiv University | Solntsev P.V.,Kyiv University | Krautscheid H.,University of Leipzig | Zhylenko I.S.,Kyiv University | And 2 more authors.
Chemical Communications | Year: 2012

Domino cyclization of ketoenols and hydrazine leads to a series of polycondensed pyridazines, which reveal potential as rigid N-donor multidentate ligands for supramolecular synthesis of open coordination polymers. © 2012 The Royal Society of Chemistry.

Thuillot W.,Lille University of Science and Technology | Bancelin D.,Lille University of Science and Technology | Bancelin D.,University of Vienna | Ivantsov A.,Lille University of Science and Technology | And 75 more authors.
Astronomy and Astrophysics | Year: 2015

Aims. Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO. Methods. The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. Results. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids. © 2015 ESO.

Kozachenko Y.,Kyiv University | Olenko A.,La Trobe University
IEEE Transactions on Information Theory | Year: 2016

This paper starts with new aliasing-truncation error upper bounds in the sampling theorem for non-bandlimited stochastic signals. Then, it investigates Lp([0,T]) approximations of the sub-Gaussian random signals. Explicit truncation error upper bounds are established. The obtained rate of convergence provides a constructive algorithm for determining the sampling rate and the sample size in the truncated Whittaker-Kotel'nikov-Shannon expansions to ensure the approximation of the sub-Gaussian signals with given accuracy and reliability. Some numerical examples are presented. © 2016 IEEE.

Banakh T.,Lviv University | Petrenko O.,Kyiv University | Protasov I.,Kyiv University | Slobodianiuk S.,Kyiv University
Electronic Journal of Combinatorics | Year: 2012

Let G be a group and X be a G-space with the action G× X → X, (g, x) → gx. A subset F of X is called a kaleidoscopical configuration if there exists a coloring X: X → C such that the restriction of X on each subset gF, g ∈ G, is a bijection. We present a construction (called the splitting construction) of kaleidoscopical configurations in an arbitrary G-space, reduce the problem of characterization of kaleidoscopical configurations in a finite Abelian group G to a factorization of G into two subsets, and describe all kaleidoscopical configurations in isometrically homogeneous ultrametric spaces with finite distance scale. Also we construct 2 c (unsplittable) kaleidoscopical configurations of cardinality c in the Euclidean space R n.

Savin S.,Russian Academy of Sciences | Zelenyi L.,Russian Academy of Sciences | Amata E.,National institute for astrophysics | Budaev V.,RAS Research Center Kurchatov Institute | And 18 more authors.
Planetary and Space Science | Year: 2011

The scientific rationale of the ROY multi-satellite mission addresses multiscale investigations of plasma processes in the key magnetospheric regions with strong plasma gradients, turbulence and magnetic field annihilation in the range from electron inertial length to MHD scales. The main scientific aims of ROY mission include explorations of: turbulence on a non-uniform background as a keystone for transport processes;structures and jets in plasma flows associated with anomalously large concentration of kinetic energy; their impact on the energy balance and boundary formation;transport barriers: plasma separation and mixing, Alfvenic collapse of magnetic field lines and turbulent dissipation of kinetic energy;self-organized versus forced reconnection of magnetic field lines;collisionless shocks, plasma discontinuities and associated particle acceleration processes. In the case of autonomous operation, 4 mobile spacecrafts of about 200 kg mass with 60 kg payload equipped with electro-reactive plasma engines will provide 3D measurements at the scales of 10010000 km and simultaneous 1D measurements at the scales 101000 km. The latter smaller scales will be scanned with the use of radio-tomography (phase-shift density measurements within the cone composed of 1 emitting and 3 receiving spacecrafts). We also discuss different opportunities for extra measurement points inside the ROY mission for simultaneous measurements at up to 3 scales for the common international fleet. Combined influence of intermittent turbulence and reconnection on the geomagnetic tail and on the nonlinear dynamics of boundary layers will be explored in situ with fast techniques including particle devices under development, providing plasma moments down to 30 ms resolution. We propose different options for joint measurements in conjunction with the SCOPE and other missions: simultaneous sampling of low- and high-latitudes magnetopause, bow shock and geomagnetic tail at the same local time;tracing of magnetosheath streamlines from the bow shock to near-Earth geomagnetic tail;passing through the SCOPE on the inbound orbit leg;common measurements (with SCOPE and other equatorial spacecraft) at distances of ∼ few thousand km for durations of ∼several hours per orbit. The orbit options and scientific payload of possible common interest are discussed in this work, including FREGAT cargo opportunities for extra payload launching and the Swarm campaigns with ejection of nano- and pico-satellites. © 2009 Elsevier Ltd. All rights reserved.

Olenko A.Y.,La Trobe University | Olenko A.Y.,Kyiv University | Wong K.T.,Hong Kong Polytechnic University | Qasmi S.A.,Canada Pension Plan Investment Board
European Transactions on Telecommunications | Year: 2013

For radiowave landmobile cellular wireless communication in 'bad urban' environments dominated by high rises, this paper analytically derives closed-form expressions for the trivariate and bivariate joint distributions of the time-of-arrival and two-dimensional azimuth-elevation direction-of-arrival of the uplink multipaths. These expressions are explicitly in terms of the parameters of a 'geometrical' model of the three-dimensional spatial relationships among the mobile station, the scatterers and the base station. This present 'geometric model' idealises the scatterers as uniformly located within the volume of a three-dimensional vertical above-ground cylinder whose flat bottom circular base centres at the mobile. Copyright © 2012 John Wiley and Sons, Ltd.

PubMed | Kyiv University
Type: Journal Article | Journal: Chemical communications (Cambridge, England) | Year: 2012

Domino cyclization of ketoenols and hydrazine leads to a series of polycondensed pyridazines, which reveal potential as rigid N-donor multidentate ligands for supramolecular synthesis of open coordination polymers.

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