2,833 research outputs found
THE STATE POLICY OF THE RUSSIAN FEDERATION ON THE NORTHERN AND ARCTIC TERRITORIES IN THE 1990S: STAGES, PRIORITIES, MECHANISMS, AND RESULTS
Purpose: The purpose of the study is to determine the state policy of the Russian Federation on the Northern and Arctic territories in the 1990s.
Methodology: This is analytical-logical research that has been done through content analysis and documentary and library research.
Result: Results showed that First of all Russia abruptly changed the priorities of its policy to the Far North setting the course to leave the region in all spheres. Dozens of polar expeditions from the USA, Norway, and Germany were sent to the Russian sector of polar lands. Russia itself rapidly turned off its economic presence in the North. “The North Pole-31” (drifting polar station) was stopped for 12 years on June 25, 1991.
Applications: This research can be used for universities, teachers, and students.
Novelty/Originality: In this research, the model of the state policy of the Russian Federation on the northern and arctic territories in the 1990s is presented in a comprehensive and complete manner
Turbulent Origin of the Galactic-Center Magnetic Field: Nonthermal Radio Filaments
A great deal of study has been carried out over the last twenty years on the
origin of the magnetic activity in the Galactic center. One of the most popular
hypotheses assumes milli-Gauss magnetic field with poloidal geometry, pervading
the inner few hundred parsecs of the Galactic-center region. However, there is
a growing observational evidence for the large-scale distribution of a much
weaker field of B \lesssim 10 micro G in this region. Here, we propose that the
Galactic-center magnetic field originates from turbulent activity that is known
to be extreme in the central hundred parsecs. In this picture the spatial
distribution of the magnetic field energy is highly intermittent, and the
regions of strong field have filamentary structures. We propose that the
observed nonthermal radio filaments appear in (or, possibly, may be identified
with) such strongly magnetized regions. At the same time, the large-scale
diffuse magnetic field is weak. Both results of our model can explain the
magnetic field measurements of the the Galactic-center region. In addition, we
discuss the role of ionized outflow from stellar clusters in producing the long
magnetized filaments perpendicular to the Galactic plane.Comment: 11 pages, accepted to ApJ Letter
Nonlinear energy transfers in accretion discs MRI turbulence. I-Net vertical field case
The magnetorotational instability (MRI) is believed to be responsible for
most of the angular momentum transport in accretion discs. However, molecular
dissipation processes may drastically change the efficiency of MRI turbulence
in realistic astrophysical situations. The physical origin of this dependency
is still poorly understood as linear and quasi linear theories fail to explain
it. In this paper, we look for the link between molecular dissipation processes
and MRI transport of angular momentum in non stratified shearing box
simulations including a mean vertical field. We show that magnetic helicity is
unimportant in the model we consider. We perform a spectral analysis on the
simulations tracking energy exchanges in spectral space when turbulence is
fully developed. We find that the energy exchanges are essentially direct (from
large to small scale) whereas some non linear interactions appear to be non
local in spectral space. We speculate that these non local interactions are
responsible for the correlation between turbulent transport and molecular
dissipation. We argue that this correlation should then disappear when a
significant scale separation is achieved and we discuss several methods by
which one can test this hypothesis.Comment: 10 pages, 9 figures, accepted for publication in Astronomy &
Astrophysic
Отдаленный результат хирургической коррекции ишемической митральной недостаточности у больной с заднебазальной постинфарктной аневризмой левого желудочка
The article presents a long-term result of surgical correction of ischemic mitral valve insufficiency, left ventricle inferior wall reconstruction. В статье представлен отдаленный результат хирургической коррекции ишемической митральной недостаточности с пластикой постинфарктной заднебазальной аневризмы левого желудочка.
Vibrational spectroscopy of GdCr3(BO3)4: Quantitative separation of crystalline phases
This work is devoted to the investigation of GdCr3(BO3)4 crystals by the method of infrared spectroscopy. Incongruently melting borate GdCr3(BO3)4 was obtained as a result of spontaneous crystallization. Crystal structures were identified by the method of infrared spectroscopy. Ab initio calculations in the frame of density functional theory enabled us to separate modes belonging to the R32 and C2/c phases and to estimate the ratio of these phases in GdCr3(BO3)4 crystals. We have found that the content of the rhombohedral R32 (non- centrosymmetric) modification is about 85%. © Published under licence by IOP Publishing Ltd
Compressible Sub-Alfvenic MHD turbulence in Low-beta Plasmas
We present a model for compressible sub-Alfvenic isothermal
magnetohydrodynamic (MHD) turbulence in low-beta plasmas and numerically test
it. We separate MHD fluctuations into 3 distinct families - Alfven, slow, and
fast modes. We find that, production of slow and fast modes by Alfvenic
turbulence is suppressed. As a result, Alfven modes in compressible regime
exhibit scalings and anisotropy similar to those in incompressible regime. Slow
modes passively mimic Alfven modes. However, fast modes show isotropy and a
scaling similar to acoustic turbulence.Comment: 4 pages, 8 figures, Phys. Rev. Lett., in pres
Turbulent Mixing in the Interstellar Medium -- an application for Lagrangian Tracer Particles
We use 3-dimensional numerical simulations of self-gravitating compressible
turbulent gas in combination with Lagrangian tracer particles to investigate
the mixing process of molecular hydrogen (H2) in interstellar clouds. Tracer
particles are used to represent shock-compressed dense gas, which is associated
with H2. We deposit tracer particles in regions of density contrast in excess
of ten times the mean density. Following their trajectories and using
probability distribution functions, we find an upper limit for the mixing
timescale of H2, which is of order 0.3 Myr. This is significantly smaller than
the lifetime of molecular clouds, which demonstrates the importance of the
turbulent mixing of H2 as a preliminary stage to star formation.Comment: 10 pages, 5 figures, conference proceedings "Turbulent Mixing and
Beyond 2007
Topological mechanochemistry of graphene
In view of a formal topology, two common terms, namely, connectivity and
adjacency, determine the quality of C-C bonds of sp2 nanocarbons. The feature
is the most sensitive point of the inherent topology of the species so that
such external action as mechanical deformation should obviously change it and
result in particular topological effects. The current paper describes the
effects caused by uniaxial tension of a graphene molecule in due course of a
mechanochemical reaction. Basing on the molecular theory of graphene, the
effects are attributed to both mechanical loading and chemical modification of
edge atoms of the molecule. The mechanical behavior is shown to be not only
highly anisotropic with respect to the direction of the load application, but
greatly dependent on the chemical modification of the molecule edge atoms thus
revealing topological character of the graphene deformation.Comment: 9 pages, 10 figures, 1 table. arXiv admin note: text overlap with
arXiv:1301.094
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