240 research outputs found
Decoration of MoSI Nanowires with Platinum Nanoparticles and Transformation into Molybdenum-nanowire Nased Networks
In this communication, we present solution-based coating procedure of MoSI nanowires (NW) with
platinum nanoparticles. The average particle diameter was found to be around 2.82 nm, showing a narrow
size distribution. This single-step in situ reduction method at room temperature in water solution can
easily be applied for large-scale applications. We also prepared two-dimensional networks of MoSI NW
bundles by deposition via spraying from a purified stable dispersion in acetonitrile onto NaCl crystals and
nonconductive silicon wafer with pre-assembled molybdenum electrodes. The formation of a conductive
molybdenum network was achieved by annealing in hydrogen due to coalescence of the templates MoSI
bundles during transformation. Stable water dispersion of molybdenum NW network was prepared by
simply dissolving the NaCl substrate with molybdenum network on the surface.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3516
Decoration of MoSI Nanowires with Platinum Nanoparticles and Transformation into Molybdenum-nanowire Nased Networks
In this communication, we present solution-based coating procedure of MoSI nanowires (NW) with
platinum nanoparticles. The average particle diameter was found to be around 2.82 nm, showing a narrow
size distribution. This single-step in situ reduction method at room temperature in water solution can
easily be applied for large-scale applications. We also prepared two-dimensional networks of MoSI NW
bundles by deposition via spraying from a purified stable dispersion in acetonitrile onto NaCl crystals and
nonconductive silicon wafer with pre-assembled molybdenum electrodes. The formation of a conductive
molybdenum network was achieved by annealing in hydrogen due to coalescence of the templates MoSI
bundles during transformation. Stable water dispersion of molybdenum NW network was prepared by
simply dissolving the NaCl substrate with molybdenum network on the surface.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3516
Reconstructed Rough Growing Interfaces; Ridgeline Trapping of Domain Walls
We investigate whether surface reconstruction order exists in stationary
growing states, at all length scales or only below a crossover length, . The later would be similar to surface roughness in growing crystal
surfaces; below the equilibrium roughening temperature they evolve in a
layer-by-layer mode within a crossover length scale , but are always
rough at large length scales. We investigate this issue in the context of KPZ
type dynamics and a checker board type reconstruction, using the restricted
solid-on-solid model with negative mono-atomic step energies. This is a
topology where surface reconstruction order is compatible with surface
roughness and where a so-called reconstructed rough phase exists in
equilibrium. We find that during growth, reconstruction order is absent in the
thermodynamic limit, but exists below a crossover length , and that this local order fluctuates critically. Domain walls become
trapped at the ridge lines of the rough surface, and thus the reconstruction
order fluctuations are slaved to the KPZ dynamics
Generic flow profiles induced by a beating cilium
We describe a multipole expansion for the low Reynolds number fluid flows
generated by a localized source embedded in a plane with a no-slip boundary
condition. It contains 3 independent terms that fall quadratically with the
distance and 6 terms that fall with the third power. Within this framework we
discuss the flows induced by a beating cilium described in different ways: a
small particle circling on an elliptical trajectory, a thin rod and a general
ciliary beating pattern. We identify the flow modes present based on the
symmetry properties of the ciliary beat.Comment: 12 pages, 6 figures, to appear in EPJ
Molecular dynamics in tilted bilayer smectic phases: a proton nuclear magnetic resonance relaxometry study
A proton nuclear magnetic resonance (NMR) relaxation study of molecular dynamics in the liquid crystal 4-octylphenyl 2-chloro-4-(4-cyanobenzoyloxy)benzoate (DB8Cl) is presented. DB8Cl molecules possess a strong polar terminal group and form, in addition to the nematic phase, three different smectic phases: bilayer smectic A, bilayer smectic C, and anticliniclike smectic C phase. The proton spin-lattice relaxation times were measured in all mesophases over a broad frequency range of six decades by applying conventional and fast field-cycling NMR techniques. The parameters obtained in the analysis of the experimental data give quantitative information on molecular motions, particularly for the tilted smectic phases of DB8Cl. In contrast to former conjectures, we found that the low-frequency relaxation in the bilayer smectic C phases results from director fluctuations about the layer normal, which occur without distortion of the layers, and from layer undulations, similar to those in the smectic A phase. In the low-temperature bilayer smectic C phase, a considerable slowing-down of molecular translational diffusion is observed. It confirms indirectly the anticlinic character of this mesophase. Measurements of angular dependence of the relaxation times at 60 MHz support the conclusions obtained from the frequency dispersion data.info:eu-repo/semantics/publishedVersio
Anomalous thickness dependence of the Hall effect in ultrathin Pb layers on Si(111)
The magnetoconductive properties of ultrathin Pb films deposited on Si(111)
are measured and compared with density-functional electronic band-structure
calculations on two-dimensional, free-standing, 1 to 8 monolayers thick Pb(111)
slabs. A description with free-standing slabs is possible because it turned out
that the Hall coefficient is independent of the substrate and of the
crystalline order in the film. We show that the oscillations in sign of the
Hall coefficient observed as a function of film thickness can be explained
directly from the thickness dependent variations of the electronic
bandstructure at the Fermi energy.Comment: 4 pages incl. 3 figures, RevTeX, to appear in Phys. Rev.
Active beating of a reconstituted synthetic minimal axoneme
Propelling microorganisms through fluids and moving fluids along cellular surfaces are essential biological functions accomplished by long, thin structures called motile cilia and flagella, whose regular, oscillatory beating breaks the time-reversal symmetry required for transport. Although top-down experimental approaches and theoretical models have allowed us to broadly characterize such organelles and propose mechanisms underlying their complex dynamics, constructing minimal systems capable of mimicking ciliary beating and identifying the role of each component remains a challenge. Here we report the bottom-up assembly of a minimal synthetic axoneme, which we call a synthoneme, using biological building blocks from natural organisms, namely pairs of microtubules and cooperatively associated axonemal dynein motors. We show that upon provision of energy by ATP, microtubules undergo rhythmic bending by cyclic association-dissociation of dyneins. Our simple and unique beating minimal synthoneme represents a self-organized nanoscale biomolecular machine that can also help understand the mechanisms underlying ciliary beating
Tug-of-war in motility assay experiments
The dynamics of two groups of molecular motors pulling in opposite directions
on a rigid filament is studied theoretically. To this end we first consider the
behavior of one set of motors pulling in a single direction against an external
force using a new mean-field approach. Based on these results we analyze a
similar setup with two sets of motors pulling in opposite directions in a
tug-of-war in the presence of an external force. In both cases we find that the
interplay of fluid friction and protein friction leads to a complex phase
diagram where the force-velocity relations can exhibit regions of bistability
and spontaneous symmetry breaking. Finally, motivated by recent work, we turn
to the case of motility assay experiments where motors bound to a surface push
on a bundle of filaments. We find that, depending on the absence or the
presence of a bistability in the force-velocity curve at zero force, the bundle
exhibits anomalous or biased diffusion on long-time and large-length scales
Exact multipoint and multitime correlation functions of a one-dimensional model of adsorption and evaporation of dimers
In this work, we provide a method which allows to compute exactly the
multipoint and multi-time correlation functions of a one-dimensional stochastic
model of dimer adsorption-evaporation with random (uncorrelated) initial
states.
In particular explicit expressions of the two-point
noninstantaneous/instantaneous correlation functions are obtained. The
long-time behavior of these expressions is discussed in details and in various
physical regimes.Comment: 6 pages, no figur
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