626 research outputs found
Renormalized theory of the ion cyclotron turbulence in magnetic field--aligned plasma shear flow
The analytical treatment of nonlinear evolution of the shear-flow-modified
current driven ion cyclotron instability and shear-flow-driven ion cyclotron
kinetic instabilities of magnetic field--aligned plasma shear flow is
presented. Analysis is performed on the base of the nonlinear dispersion
equation, which accounts for a new combined effect of plasma turbulence and
shear flow. It consists in turbulent scattering of ions across the shear flow
with their convection by shear flow and results in enhanced nonlinear
broadening of ion cyclotron resonances. This effect is found to lead to the
saturation of ion cyclotron instabilities as well as to the development of
nonlinear shear flow driven ion cyclotron instability. 52.35.RaComment: 21 page
Semantic features of the phraseological units with the component light within the artistic discourse
Conduct lexical and semantic analysis on the concept light in the artistic discourse of postmodern fictio
Low molecular weight thymic factor inhibits histamine release from basophils
Low molecular weight thymic factor stimulates the suppressor function of T-lymphocytes, increases cAMP content (but not cGMP) in lymphocytes and inhibits histamine release from sensitized basophils. The mechanisms of LTF action are discussed
SEMANTIC FEATURES OF THE PHRASEOLOGICAL UNITS WITH THE COMPONENT LIGHT THE WITHIN ARTISTIC DISCOURSE
Purpose: To conduct lexical and semantic analysis on the concept light in the artistic discourse of postmodern fiction.
Methodology: In this research, comparative method, search for synonyms, continuous sampling and seminal analysis are used.
Main Findings: As a result, it becomes obvious that the boundaries of the artistic concepts are extremely blurred and much wider than the boundaries of the corresponding non-artistic concepts. In conclusion, the concept light is frequently used in English artistic discourses, i.e. significant in the culture, and a special status in the semantic space of the concept light has the meaning of knowledge and information.
Applications: The study results can be used by students and universities.
Novelty/Originality: In this research, a model of the semantic features of the phraseological units with the component light is presented in a comprehensive and complete manner
The bubbles of matter from multiskyrmions
The multiskyrmions with large baryon number B given by rational map (RM)
ansaetze can be described reasonably well within the domain wall approximation,
or as spherical bubbles with energy and baryon number density concentrated at
their boundary. A special class of profile functions is considered
approximating the true profile and domain wall behaviour at the same time. An
upper bound is obtained for the masses of RM multiskyrmions which is close to
the calculated masses, especially at large B. The gap between rigorous upper
and lower bounds for large B multiskyrmions is less than 4%. The basic
properties of such bubbles of matter are investigated, some of them being of
universal character, i.e. they do not depend on baryon number of configuration
and on the number of flavors. As a result, the lagrangian of the Skyrme type
models provides field theoretical realization of the bag model of special kind.Comment: 7 pages, no figure
Multiskyrmions and baryonic bags
Analytical treatment of skyrmions given by rational map (RM) ansaetze
proposed recently for the Skyrme model is extended to the model including the
6-th order term in chiral fields derivatives in the lagrangian (the SK6 variant
of the model) and used for calculation of different properties of
multiskyrmions. For special class of profile functions approximating the true
profile and the domain wall behaviour at the same time, the masses and other
static properties of multiskyrmions are expressed in terms of the Euler-type
integrals. An upper bound is obtained for the masses of RM multiskyrmions which
is close to the calculated masses, especially at large B. The gap between
rigorous upper bound and lower bound, obtained for the SK6 model as well, for
large B multiskyrmions is less than 9%, in comparison with about 4% for the SK4
(Skyrme) variant. The basic properties of such bubbles of matter are
investigated, some of them, e.g. the thickness of the bubbles envelope, being
of universal character, i.e. they do not depend on baryon number of
configuration, or reveal a simple and natural dependence. The dependence of
these properties on the number of flavours is absent or very weak in both
models. Qualitatively, the properties of the baryonic bags are the same for the
SK6 and SK4 variants of the model, although differ in some details.Comment: 16 pages, no figure
Polar mesosphere winter echoes during solar proton events
Thin layers of enhanced radar echoes in the winter mesosphere have been observed by the ESRAD 52 MHz MST radar (67°53 \u27 N, 21°06 \u27 E) during several recent solar proton events. These polar mesosphere winter echoes (PMWE) can occur at any time of day or night above 70 km altitude, whereas below this height they are seen only during daytime. An energy deposition / ion-chemical model is used to calculate electron and ion densities from the observed proton fluxes. It is found that PMWE occurrence correlates well with low values of λ(the ratio of negative ion density to electron density). There is a sharp cut-off in PMWE occurrence at λ~10^, which is independent of electron density. No direct dependence of PMWE occurrence on electron density can be found within the range represented by the solar proton events, with PMWE being observed at all levels of electron density corresponding to values of λ. Together with results concerning the thickness, echo aspect-sensitivity and echo spectral-width of the PMWE, this observation leads to the conclusion that the layers cannot be explained by turbulence alone. A role for charged aerosols in creating PMWE is proposed
Ferromagnetism in the Mott insulator Ba2NaOsO6
Results are presented of single crystal structural, thermodynamic, and
reflectivity measurements of the double-perovskite Ba2NaOsO6. These
characterize the material as a 5d^1 ferromagnetic Mott insulator with an
ordered moment of ~0.2 Bohr magnetons per formula unit and TC = 6.8(3) K. The
magnetic entropy associated with this phase transition is close to Rln2,
indicating that the quartet groundstate anticipated from consideration of the
crystal structure is split, consistent with a scenario in which the
ferromagnetism is associated with orbital ordering.Comment: 5 pages, 5 figures, added reference
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