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Novikov D.V.,The Bonch-Bruevich St. Petersburg State University of Telecommunications | Krasovskii A.N.,Saint Petersburg State University | Mnatsakanov S.S.,Saint Petersburg State University
Physics of the Solid State | Year: 2012

The topology of the surface of thin films obtained from cellulose triacetate solutions has been studied using electron microscopy. The domain structure of the physical network of macromolecules (percolation cluster) with the maximum size L ≈ 30 nm of regions with a local orientational order has been established. With an increase in the volume fraction Ω of the cluster to the critical value Ω = 0. 91, repacking of domains takes place, which is connected with a decrease in the parameter Ω, L doubling bifurcation of the size L, and formation of regions of long-range orientational order: the mesophase of the polymer. © 2012 Pleiades Publishing, Ltd.


Marcos S.,University of Cantabria | Lopez-Quelle M.,University of Cantabria | Niembro R.,University of Cantabria | Savushkin L.N.,The Bonch-Bruevich St. Petersburg State University of Telecommunications
Physics of Atomic Nuclei | Year: 2012

The effect of an interaction between the σ- and π-meson fields, as well as that of the mixture of pseudoscalar (PS) and pseudovector (PV) couplings for the πN vertex on the shell structure of finite nuclei are analyzed in the framework of different nonlinear nuclearmodels based on the relativistic Hartree-Fock approximation. For the case of a dominant πN PV coupling, it is found that if the σ-π interaction generates an effective pion mass increasing with the nuclear density, the unrealistic effect of pions on the shell structure can be strongly reduced, keeping, roughly, the contribution of pions to the total binding energy. The πN PS coupling increases slightly the spin-orbit splittings and the binding energy of the single-particle levels. © 2012 Pleiades Publishing, Ltd.


Niembro R.,University of Cantabria | Marcos S.,University of Cantabria | Lopez-Quelle M.,University of Cantabria | Savushkin L.N.,The Bonch-Bruevich St. Petersburg State University of Telecommunications
Physics of Atomic Nuclei | Year: 2012

Relativistic nonlinear models based on the Hartree and Hartree-Fock approximations, including the σ, ω, π, and ρ mesons, are worked out to explore the behavior of the nuclear charge radii and the binding energies of several isotopic chains. We find a correlation between the magnitude of the anomalous kink effect (KE) in the Pb isotopic family and the compressibility modulus (K) of nuclear matter. The KE appears to be sensitive, in particular, to the mechanisms which control the K value. The influence of the symmetry energy on the Ca isotopic chain is also studied. The behavior of the charge radii of single-particle states for some special cases and its repercussion on the nuclear charge radius is analyzed. The effect of pairing correlations on the models improves considerably the quality of the results in both binding energy and KE. © 2012 Pleiades Publishing, Ltd.


Sivers M.,Saint Petersburg State Polytechnic University | Fokin G.,The Bonch-Bruevich St. Petersburg State University of Telecommunications
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

In this paper we investigate the positioning accuracy of user equipment (UE) with observed time difference of arrival (OTDoA) technique in Long Term Evolution (LTE) networks using dedicated positioning reference signal (PRS) by means of comprehensive simulation model. System-level model includes typical cellular network layout with spatially distributed eNodeB (eNB) and link-level model simulates PRS transmission and reception with LTE System Toolbox. Matlab “TDOA Positioning Using PRS example” was developed to include known linear least squares (LLS), nonlinear Gauss-Newton (GN) and Levenberg-Marquardt (LM) positioning algorithms and compare it with Cramer-Rao lower bound (CRLB). Resulting estimates clarify known results and reveal that simple LLS achieves close to LM positioning accuracy when the number of eNB is 6, while further increasing the number of eNB degrades positioning algorithms accuracy. © Springer International Publishing Switzerland 2015.


Marcos S.,University of Cantabria | Lopez-Quelle M.,University of Cantabria | Niembro R.,University of Cantabria | Savushkin L.N.,The Bonch-Bruevich St. Petersburg State University of Telecommunications
Physics of Atomic Nuclei | Year: 2014

The binding energies of several isotopic families are studied within the relativistic Hartree-Fock approximation with the pseudovector coupling for the πN vertex, to find out a suitable strength for the effective pion tensor force (EPTF). An approximation for determining separately the contributions of the central and tensor forces generated by pion is considered. The results for heavy nuclei indicate that a realistic strength for the EPTF is smaller than a half of that appearing in the OPEP. This conclusion also applies to the results for the single-particle energies. Besides, it has been found that there is a genuine relativistic contribution of the EPTF in nuclear matter which is small but significant. © 2014 Pleiades Publishing, Ltd.

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