Electrochemical Cr (III) oxidation with doped PbO2 anodes

The electrochemical oxidation of Cr (III) is of great importance in many electrochemical productions. One of the most common anodic electrode materials for this process is PbO2, due to its high corrosion resistance in acidic media at high anodic potentials. In this paper, the rate constants of the anodic reaction of oxygen transfer in Na2SO4 and H2SO4 solutions containing Cr3+ at the volume-doped electrodes based on PbO2 were estimated by using a rotating disk electrode

Cooperative localization-delocalization in the high Tc cuprates

The intrinsic metastable crystal structure of the cuprates results in local dynamical lattice instabilities, strongly coupled to the density fluctuations of the charge carriers. They acquire in this way simultaneously both, delocalized and localized features. It is responsible for a partial fractioning of the Fermi surface, i.e., the Fermi surface gets hidden in a region around the anti-nodal points, because of the opening of a pseudogap in the normal state, arising from a partial charge localization. The high energy localized single-particle features are a result of a segregation of the homogeneous crystal structure into checker-board local nano-size structures, which breaks the local translational and rotational symmetry. The pairing in such a system is dynamical rather than static, whereby charge carriers get momentarily trapped into pairs in a deformable dynamically fluctuating ligand environment. We conclude that the intrinsically heterogeneous structure of the cuprates must play an important role in this type of superconductivity.Comment: 14 pages, 8 figures, Proceedings of the "International Conference on Condensed Matter Theories", Quito, 2009 Int. J. Mod. Phys. B 2010 (Accepted

Electrochemical deposition of nickel coatings from acetate-chloride electrolyte in pulse mode

The process of electrodepositing of nickel from acetate-chloride electrolyte at low temperature in a pulsed mode has been investigated. It is established that application of pulsed electrolysis mode allows to increase the working current density up to 9 A/dm2. A nanostructured nickel coating with a maximum size of crystallites of 200 nm is obtained. The results show that the use of pulsed electrolysis makes possible to reduce porosity of coating thicknesses up to 20 ?m.The process of electrodepositing of nickel from acetate-chloride electrolyte at low temperature in a pulsed mode has been investigated. It is established that application of pulsed electrolysis mode allows to increase the working current density up to 9 A/dm2. A nanostructured nickel coating with a maximum size of crystallites of 200 nm is obtained. The results show that the use of pulsed electrolysis makes possible to reduce porosity of coating thicknesses up to 20 ?m,Chemistry and Technology of Inorganic Materials and Substance

The use of pulse electrolysis for copper plating on steel and cast iron bases from citrate electrolyte

Process of electrochemical deposition of copper on a steel and iron substrate from citrate electrolytes was investigated. It is determined that the material of cathode greatly influences the kinetics of copper plating process. Influence of pulse electrolysis on a range of working density of current, a current efficiency of copper and porosity of coatings were investigated. It is determined that application of a pulse mode increases a range of working density of current and improves quality of the received coatings

Superconductivity in charge Kondo systems

We present a theory of superconductivity in charge Kondo systems, materials with resonant quantum valence fluctuations, in the regime where the transition temperature is comparable to the charge Kondo resonance. We find superconductivity induced by charge Kondo impurities, study how pairing of a superconducting host is enhanced due to charge Kondo centers and investigate the interplay between Kondo-scattering and inter-impurity Josephson coupling. We discuss the implications of our theory for Tl-doped PbTe, which has recently been identified as a candidate charge Kondo system.Comment: 4 pages, 4 figures; revised version; detailed discussion on the physics of Tl-doped PbTe adde

The numerical solution of the free-boundary cell motility problem

The cell motility problem has been investigated for a long time. Today, many biologists, physicists, and mathematicians are looking for new research instruments for this process. A simple 2D model of a free-boundary cell moving on a homogeneous isotropic surface is presented in the paper. It describes the dynamics of the complex actomyosin liquid, whose special properties influence the boundary dynamics and cell motility. The model consists of a system of equations with the free boundary domain and contains a non-local term. In this work, we present a numerical solution of this problem

Model of Motion of the Combined Manipulator

The combined manipulators composed of telescopic booms and rotary supports with movable in longitudinal vertical plane columns which provide an increased outreach of operative parts and a bigger service space are widely used in different branches of industry (engineering, transport). The article considers development of mathematical model of kinematic links motion of the combined manipulator with a column movable in longitudinal vertical plane. The mode of load lifting in a synchronous movement of boom and column from the position of picking the load up to the transport position was analyzed

Etching technology in formation of self-organized aluminum mesh for sensor and display applications

В статье описаны исследования влияния температуры и концентрации по травлению нанопористого глинозема в технологии производства самоорганизующегося алюминиевой сетки для сенсоров и дисплеев