1,295 research outputs found
Group analysis and renormgroup symmetries
An original regular approach to constructing special type symmetries for
boundary value problems, namely renormgroup symmetries, is presented. Different
methods of calculating these symmetries, based on modern group analysis are
described. Application of the approach to boundary value problems is
demonstrated with the help of a simple mathematical model.Comment: 17 pages, RevTeX LATeX file, to appear in Journal of Mathematical
Physic
Demonstrating Entanglement by Testing Bell's Theorem in Majorana Wires
We propose an experiment that would establish the entanglement of Majorana
zero modes in semiconductor nanowires by testing the Bell and
Clauser-Horne-Shimony-Holt inequalities. Our proposal is viable with realistic
system parameters, simple "keyboard" gating, and projective measurement.
Simulation results indicate entanglement can be demonstrated with moderately
accurate gate operations. In addition to providing further evidence for the
existence of the Majorana bound states, our proposal could be used as an
experimental stepping stone to more complicated braiding experiments.Comment: 11 pages, 8 figures, 2 table
The confinement of phonon propagation in TiAlN/Ag multilayer coatings with anomalously low heat conductivity
TiAlN/Ag multilayer coatings with a different number of bilayers and thicknesses of individual layers were fabricated by DC magnetron co-sputtering. Thermal conductivity was measured in dependence of Ag layer thickness. It was found anomalous low thermal conductivity of silver comparing to TiAlN and Ag bulk standards and TiAlN/TiN multilayers. The physical nature of such thermal barrier properties of the multilayer coatings was explained on the basis of reflection electron energy loss spectroscopy. The analysis shows that nanostructuring of the coating decreases the density of states and velocity of acoustic phonons propagation. At the same time, multiphonon channels of heat propagation degenerate. These results demonstrate that metal-dielectric interfaces in TiAlN/Ag coatings are insurmountable obstacles for acoustic phonons propagation
Determining the Young's modulus of a cellular titanium implant by FEM simulation
The role of additive manufacturing is noted for the construction of titanium medical implants. The purpose of the study is to determine the Young's modulus of cellular titanium implants, which is based on calculations performed by finite element analysis. A honeycomb structure from intersecting cylinder surfaces is offered for the implant made of the Ti-6Al-4V alloy. Boundary conditions are stated for the loading of the implant structure. It is demonstrated that the Young's modulus can be reduced more than three times comparing to a solid titanium alloy. Zones of strain and stress localization located near the abutment of the cylindrical surfaces. Recommendations for the further improvement of the implant architecture are generated. © 2017 Author(s).Ministry of Education and Science of the Russian Federation, Minobrnauka: 218We hereby acknowledge the support of the Ministry of Science and Education of the Russian Federation, in accordance with the decree of the Government of April 9, 2010, No. 218, project number 03.G25.31.0234
The orbits of outer planetary satellites using the Gaia data
Launch of the Gaia space observatory started a new era in astrometry when the
accuracy of star coordinates increased by thousands of times. Significant
improvement of accuracy was also expected for the coordinates of the Solar
system bodies. Gaia DR3 provided us with the data which could be used to test
our expectations. In this work, we refine the orbits of a number of outer
planetary satellites using both ground-based and Gaia observations. From
thirteen outer satellites observed by Gaia, we chose six to obtain their
orbits. Some specific moments in using observations of outer satellites made by
Gaia are demonstrated. These pecularities stem from scanning motion of Gaia, in
particular from the fact that the accuracy of observations is significantly
different along and across the scanning direction. As expected, Gaia
observations proved to be more precise than those made from Earth, which
results in more accurate satellite ephemerides. We estimate accuracy of the
ephemerides of considered satellites for the interval between 1996 and 2030. As
astrometric positions published in Gaia DR3 were not corrected for the
relativistic light deflection by the Sun, we took into account this effect,
which slightly diminished the rms residuals. In addition, relativistic light
deflection by the giant planets was estimated, which, as it turned out, can be
neglected with the given accuracy of Gaia observations.Comment: accepted in MNRAS 28.03.2023, 9 pages, 8 figure
The Concept of Sustainability as an Instrument of New Humanitarian Diplomacy
The article deals with the evolution, basic principles, principles and models of the concept of sustainable development. Characteristed types of stability. Relations in the system «socium-ecology-economy», their coherence and coevolution are analyzed. The instability of modern international relations and the role of humanitarian diplomacy in the creation of sustainable models are demonstrated.В статье рассматривается эволюция, основные положения, принципы и модели концепции устойчивого развития. Характеризуются виды устойчивости. Анализируются отношения в системе «социум – экология – экономика», их когерентность и коэволюция. Демонстрируется неустойчивость современных международных отношений и роль гуманитарной дипломатии в создание устойчивых моделей
X-ray Diffraction Study of Superstructure in GdBaCo2O5.5
A single crystal of GdBaCo2O5.47(2) has been studied by means of X-ray
diffraction. Appearance of superstructure reflections at T = 341.5(7) K gives
an evidence of continuous transition to the phase with unit cell doubled along
the shortest edge a1. Critical exponent for the order parameter is found to be
beta=0.33(1). The superstructure reflections are about 2-4 orders of magnitude
weaker than the basic ones. Their systematic extinction indicates the crystal
symmetry change from Pmmm to Pmma. The integrated intensities allow to
calculate displacements of atoms from the positions in the high-temperature
phase. The cobalt-ligand distances in the ordered phase are discussed in terms
of the spin-state/orbital ordering of Co3+ ions.Comment: 4 page
Survey of Instantaneous 1-22 GHz Spectra of 550 Compact Extragalactic Objects with Declinations from -30deg to +43deg
We present observational results for extragalactic radio sources with
milliarcsecond components, obtained with the 600 meter ring radio telescope
RATAN-600 from 1st to 22nd December, 1997. For each source, a six frequency
broad band radio spectrum was obtained by observing simultaneously with an
accuracy up to a minute at 1.4, 2.7, 3.9, 7.7, 13 and 31 cm. The observed list
is selected from Preston et al. (1985) VLBI survey and contains all the sources
in the declinations between -30deg and +43deg with a correlated flux density
exceeding 0.1 Jy at 13 cm. The sample includes the majority of sources to be
studied in the current VSOP survey and the future RadioAstron Space VLBI
mission.Comment: 26 pages, 4 figures, 5 tables, published in the A&AS; figure 4 with
the broad-band spectra plots is included in the preprint; tables 1 and 5, in
electronic form, as well as the ReadMe file can be extracted from the
preprint sourc
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