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M. Vovk

Publications and source records attributed to M. Vovk.

7 recordsLinked to original sources
arXiv2021

Light-controllable chiral dopant based on azo-fragment: synthesis and characterization

We present the newly synthesized chiral dopant 2-[(2-isopropyl-5-methylcyclohexyl)oxy]-2-oxoethyl 4-{(E)-[4-(decyloxy)phenyl]diazenyl}benzoate (ChD-3501), consisting of azo- and aliphatic fragments together with a chiral center based on l-menthol as a reversible light-controllable chiral dopant. To assess the effects of UV/VIS irradiation and temperature in the isotropic and liquid crystalline (LC) states, we studied the spectral kinetics of ethanol solution of ChD-3501, as well as induction of the cholesteric helix when it was dissolved in nematic LC (E7) as a chiral dopant. The concentration dependence of the helical pitch of the induced cholesterics was studied by means on Grandjean-Cano method, and the helical twisting power of ChD-3501 in the nematic host E7 was determined. The reversible trans-cis isomerization of chiral dopandt ChD-3501 in E7 under UV/VIS irradiation was studied, and it has been found that the storage of the cis-isomer at certain constant temperature also leads to the reversible isomerisation, which presents a certain interest for applications.

cond-mat.soft↗
arXiv2017

The structure of rationally factorized Lax type flows and their analytical integrability

The work is devoted to constructing a wide class of differential-functional dynamical systems, whose rich algebraic structure makes their integrability analytically effective. In particular, there is analyzed in detail the operator Lax type equations for factorized seed elements, there is proved an important theorem about their operator factorization and the related analytical solution scheme to the corresponding nonlinear differential-functional dynamical systems.

nlin.SI↗
arXiv2009

Connected economically metrizable spaces

A topological space is nonseparably connected if it is connected but all of its connected separable subspaces are singletons. We show that each connected sequential topological space X is the image of a nonseparably connected complete metric space Eco(X) under a monotone quotient map. The metric d of the space Eco(X) is economical in the sense that for each infinite subspace A of X the cardinality of the set {d(a,b):a,b in A} does not exceed the density of A. The construction of the space Eco(X) determines a functor Eco from the category Top of topological spaces and their continuous maps into the category Metr of metric spaces and their non-expanding maps.

math.GN↗
arXiv2009

Nonseparably connected complete metric spaces

A topological space is nonseparably connected if it is connected but all of its connected separable subspaces are singletons. We show that each connected first countable space is the image of a nonseparably connected complete metric space under a continuous monotone hereditarily quotient map.

math.MG↗
arXiv2009

Connected, not separably connected complete metric spaces

In a separably connected space any two points are contained in a separable connected subset. We show a mechanism that takes a connected bounded metric space and produces a complete connected metric space whose separablewise components form a quotient space isometric to the original space. We repeatedly apply this mechanism to construct, as an inverse limit, a complete connected metric space whose each separable subset is zero-dimensional.

math.GN↗
arXiv2008

On locally extremal functions on connected spaces

We construct an example of a real-valued continuous non-constant function $f$ defined on a connected complete metric space $X$ such that every point of $X$ is a point of local minimum or local maximum for $f$. The space $X$ is connected but fails to be separably connected.

math.GN↗