51 research outputs found
Plasma-assisted deposition of dielectric conformal coating using hexamethyldisiloxane as precursor
Plasma polymerization is a rapidly growing field of plasma technology. Using this method, it is possible to solve applied problems, for example, the deposition of conformal dielectric coatings to protect electrical circuit boards operating in outer space. In this paper, we study the vapor deposition of hexamethyldisiloxane using low-pressure plasma. The morphology, dielectric strength under plasma, and chemical composition of the deposited coating are studied. It was established that the coating has a lamellar structure, which, together with the data of IR spectroscopy, indirectly prove the formation of a polymer coating. The dielectric strength of the coating under plasma was 650 V
Manganese catalysts to obtain olefins from C1-C4 alkanes
Oxidative transformations of C1-C4 alkanes into olefins on oxide manganese catalysts were under study. We also studied oxidative coupling of methane (OCM) into ethylene on deposited and applied on the silicon dioxide catalysts. We studied the influence of chemical composition of catalyst and promotors on the OCM. Adding a little amount of ethane and propane hydrocarbons to methane allows increasing the concentration of ethylene in gases and significantly increasing productivity in ethylene. The study also shows the impact of the amount of manganese and promotors applied on SiO2 on the yield of olefins during the conversion of C3-C4 alkanes
Effect of atmospheric-pressure plasma jet on normal and tumor cells in vitro
The purpose of this work is to investigate the effect of low-temperature plasma on tumor and normal cells. As a result of in vitro experiments, plasma-exposed tumor and normal cells demonstrate several effects such as cell detachment, apoptosis or necrosis according to cell type and exposure parameters (power, time of exposure, frequency). In experiments, the inhibition of tumor cell growth was observed up to 70% on the 5th day after exposure. The effect of gas discharge plasma on normal cells was the opposite, and by 5 days there was a stimulation of cell proliferation. The obtained data demonstrate the prospects of using this atmospheric-pressure plasma jet in biomedical research aimed at the treatment of cancer
Phase-Space Volume of Regions of Trapped Motion: Multiple Ring Components and Arcs
The phase--space volume of regions of regular or trapped motion, for bounded
or scattering systems with two degrees of freedom respectively, displays
universal properties. In particular, sudden reductions in the phase-space
volume or gaps are observed at specific values of the parameter which tunes the
dynamics; these locations are approximated by the stability resonances. The
latter are defined by a resonant condition on the stability exponents of a
central linearly stable periodic orbit. We show that, for more than two degrees
of freedom, these resonances can be excited opening up gaps, which effectively
separate and reduce the regions of trapped motion in phase space. Using the
scattering approach to narrow rings and a billiard system as example, we
demonstrate that this mechanism yields rings with two or more components. Arcs
are also obtained, specifically when an additional (mean-motion) resonance
condition is met. We obtain a complete representation of the phase-space volume
occupied by the regions of trapped motion.Comment: 19 pages, 17 figure
Flatness is a Criterion for Selection of Maximizing Measures
For a full shift with Np+1 symbols and for a non-positive potential, locally
proportional to the distance to one of N disjoint full shifts with p symbols,
we prove that the equilibrium state converges as the temperature goes to 0. The
main result is that the limit is a convex combination of the two ergodic
measures with maximal entropy among maximizing measures and whose supports are
the two shifts where the potential is the flattest. In particular, this is a
hint to solve the open problem of selection, and this indicates that flatness
is probably a/the criterion for selection as it was conjectured by A.O. Lopes.
As a by product we get convergence of the eigenfunction at the log-scale to a
unique calibrated subaction
On the superintegrable Richelot systems
We introduce the Richelot class of superintegrable systems in N-dimensions
whose n<=N equations of motion coincide with the Abel equations on n-1 genus
hyperellipic curve. The corresponding additional integrals of motion are the
second order polynomials of momenta and multiseparability of the Richelot
superintegrable systems is related with classical theory of covers of the
hyperelliptic curves.Comment: 13 pages, a talk given at the Conference "Symmetry Methods in
Physics" devoted to the memory of Professor Y.F.Smirnov, July 6-9, 200
Geodesic flows on Riemannian g.o. spaces
We prove the integrability of geodesic flows on the Riemannian g.o. spaces of
compact Lie groups, as well as on a related class of Riemannian homogeneous
spaces having an additional principal bundle structure.Comment: 12 pages, minor corrections, final versio
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