193 research outputs found
Photoelectrochemical processes on mesoporous In2O3 sensitized with nanosized particles of lead and cadmium chalcogenides
Inhibition effect of magnesium and calcium chloride additives on anodic chlorine evolution at platinum electrode in concentrated potassium chloride aqueous electrolytes
Adaptive sliding-mode observer for second order discrete-time MIMO nonlinear systems based on recurrent neural-networks
Effect of heat treatment of TiO2 nanotubular layer on electrocatalytic activity of Au nanoparticles/TiO2 system in oxygen electroreduction reaction
Therapy chronic trichomoniasis at patients with associated urogenital chlamydial infection
Present material of problem question therapy chronic trichomoniasis. Study clinical and bacteriological effectiveness basic etiotropic preparation and their combination, used in treatment patients trichomoniasis. Found that the combined application antiprotozoal drugs have a more pronounced effect on kills T. vaginalis and shortens the rehabilitation of the patient
Band-gap and sub-band-gap photoelectrochemical processes at nanocrystalline CdS grown on ZnO by successive ionic layer adsorption and reaction method
Cadmium sulfide nanoparticle (NP) deposition by the successive ionic layer adsorption and reaction (SILAR) method on the surface of mesoporous ZnO micro-platelets with a large specific surface area (110 ± 10 m2g− 1) results in the formation of ZnO/CdS heterostructures exhibiting a high incident photon-to-current conversion efficiency (Y) not only within the region of CdS fundamental absorption (Ymax = 90%; 0.1 M Na2S + 0.1 M Na2SO3), but also in the sub-band-gap (SBG) range (Ymax = 25%). The onset potentials of SBG photoelectrochemical processes are more positive than the band-gap (BG) onset potential by up to 100 mV. A maximum incident photon-to-current conversion efficiency value for SBG processes is observed at larger amount of deposited CdS in comparison with the case of BG ones. The Urbach energy (EU) of CdS NPs determined from the photocurrent spectra reaches a maximal value on an early deposition stage (EU = 93 mV at SILAR cycle number N = 5), then lowers somewhat (EU = 73 mV at N = 10) and remains steady in the range of N from 20 to 300 (EU = 67 ± 1 mV). High efficiency of the photoelectrochemical SBG processes are interpreted in terms of light scattering in the ZnO/CdS heterostructures
Theory of differential inclusions and its application in mechanics
The following chapter deals with systems of differential equations with
discontinuous right-hand sides. The key question is how to define the solutions
of such systems. The most adequate approach is to treat discontinuous systems
as systems with multivalued right-hand sides (differential inclusions). In this
work three well-known definitions of solution of discontinuous system are
considered. We will demonstrate the difference between these definitions and
their application to different mechanical problems. Mathematical models of
drilling systems with discontinuous friction torque characteristics are
considered. Here, opposite to classical Coulomb symmetric friction law, the
friction torque characteristic is asymmetrical. Problem of sudden load change
is studied. Analytical methods of investigation of systems with such
asymmetrical friction based on the use of Lyapunov functions are demonstrated.
The Watt governor and Chua system are considered to show different aspects of
computer modeling of discontinuous systems
Polycrystalline bismuth films: correlation between grain structure and electron transport
Grain structure and the temperature dependences of resistivity, magnetoresistance, Hall and Seebeck coefficients measured in the range from 4 to 300 K were investigated for polycrystalline bismuth films obtained by the melt spinning (MS) and electrochemical deposition (ECD) methods. Charge-carrier concentration and mobilities were calculated assuming the carrier scattering on acoustic deformation potential as the dominant scattering mechanism, parabolicity of holes dispersion law, implying the Lax model for L-band electrons and neglecting the influence of L-band holes on conductivity. The experimental results and calculations have demonstrated that the electrical properties of the Bi films studied are strongly affected by the grain-boundary density
Origins of Photoluminescence Decay Kinetics in CdTe Colloidal Quantum Dots
Recent experimental studies have identified at least two nonradiative components in the fluorescence decay of solutions of CdTe colloidal quantum dots (CQDs). The lifetimes reported by different groups, however, differed by orders of magnitude, raising the question of whether different types of traps were at play in the different samples and experimental conditions and even whether different types of charge carriers were involved in the different trapping processes. Considering that the use of these nanomaterials in biology, optoelectronics, photonics, and photovoltaics is becoming widespread, such a gap in our understanding of carrier dynamics in these systems needs addressing. This is what we do here. Using the state-of-the-art atomistic semiempirical pseudopotential method, we calculate trapping times and nonradiative population decay curves for different CQD sizes considering up to 268 surface traps. We show that the seemingly discrepant experimental results are consistent with the trapping of the hole at unsaturated Te bonds on the dot surface in the presence of different dielectric environments. In particular, the observed increase in the trapping times following air exposure is attributed to the formation of an oxide shell on the dot surface, which increases the dielectric constant of the dot environment. Two types of traps are identified, depending on whether the unsaturated bond is single (type I) or part of a pair of dangling bonds on the same Te atom (type II). The energy landscape relative to transitions to these traps is found to be markedly different in the two cases. As a consequence, the trapping times associated with the different types of traps exhibit a strikingly contrasting sensitivity to variations in the dot environment. Based on these characteristics, we predict the presence of a sub-nanosecond component in all photoluminescence decay curves of CdTe CQDs in the size range considered here if both trap types are present. The absence of such a component is attributed to the suppression of type I traps
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