Über einige bestimmte Integrale,in denen die WhittakerschenM k,m -Funktionen auftreten

Ohne Zusammenfassung     

Aspects of polyaniline electrodeposition on aluminium

Electrodeposition of polyaniline (PAni) from acid solutions on spontaneous passivating electrodes such as Al is not so obvious as on active metals (Fe and Ni). The methods that can result in deposition are: (1) surface pre-treatment with a chelating agent (alizarin) to block the hydrogen evolution reaction on aluminium and (2) a suitable monomer concentration (critical monomer concentration) to decrease the polymerisation induction time. The oxidation of aluminium to thick porous film limits the growth kinetics of PAni during deposition by cyclic voltammetry. We found that after reducing hydrogen evolution by surface chelation, for film growing in 0.5 M H₂SO₄ a concentration of 0.4 M aniline is required.     

Aromatic nitro substitution reaction between 4‐nitro‐N‐n‐butyl‐1,8‐naphthalimide and n‐heptanethiol in water–methanol binary mixtures

The second‐order rate constants of thiolysis by n‐heptanethiol on 4‐nitro‐N‐n‐butyl‐1,8‐naphthalimide (4NBN) are strongly affected by the water–methanol binary mixture composition reaching its maximum at around 50% mole fraction. In parallel solvent effects on 4NBN absorption molar extinction coefficient also shows a maximum at this composition region. From the spectroscopic study of reactant and product and the known H‐bond capacity of the mixture a rationalization that involves specific solvent H‐donor interaction with the nitro group is proposed to explain the kinetic data. Present findings also show a convenient methodology to obtain strongly fluorescent imides, valuable for peptide and analogs labeling as well as for thio‐naphthalimide derivatives preparations. Copyright © 2008 John Wiley & Sons, Ltd.     

Interactions of hydrosiloxane and vinylsiloxane groups with aluminum oxide surfaces

Silicone-based materials often contain vinylsiloxane and hydrosiloxane groups for cross-linking by a radical or addition reaction. Such functional groups can influence the interactions with fillers or with surfaces of substrates when used as adhesives. This work examined how these functional groups interact with aluminum oxide surfaces. For this purpose, aluminum oxide powders with large surface areas of 150 m²/g and different acid-base properties were examined. Siloxanes were applied as thin layers to mainly obtain information from the interphase by vibrational spectroscopy. It was observed that vinyl groups show low interactions with aluminum oxide surfaces even at elevated temperatures. In contrast to this, hydrosiloxanes undergo strong interactions and reactions with aluminum oxides already at room temperature. Activated Si─H species were observed as an intermediate state. On the one hand, interactions and reactions might contribute to adhesion, but on the other hand, the cross-linking reaction can be influenced near the surface, leading to lower mechanical strength.     

Large Eddy Simulation of Spark Ignition in a Gas Turbine Combustor

Ignition in an aircraft gas turbine combustion chamber is simulated using Large Eddy Simulation (LES) in conjunction with the filtered probability density function (pdf) equation approach, which is solved using the Eulerian stochastic field method. The LES-pdf methodology is used for both dispersed (liquid) and gas phases. The liquid phase is described using a Lagrangian formulation whilst an Eulerian approach is employed for the gas phase. The spark energy deposition was mimicked by a distributed energy source term added to the enthalpy equation. Unsuccessful and successful ignition sequences have been simulated and the results suggest that spark ‘size’ is an important parameter in the ignition of kerosene fuelled combustion chambers.     

PIV studies of coherent structures generated at the end of a stack of parallel plates in a standing wave acoustic field

Oscillating flow near the end of a stack of parallel plates placed in a standing wave resonator is investigated using particle image velocimetry (PIV). The Reynolds number, Re _d , based on the plate thickness and the velocity amplitude at the entrance to the stack, is controlled by varying the acoustic excitation (so-called drive ratio) and by using two configurations of the stacks. As the Reynolds number changes, a range of distinct flow patterns is reported for the fluid being ejected from the stack. Symmetrical and asymmetrical vortex shedding phenomena are shown and two distinct modes of generating “vortex streets” are identified.     

Study on Influence of Gelatin-Alginate Matrixes on the Coagulation System and Morphotic Blood Elements

Summary: The paper presents evaluation hemolytic and hemostatic activity of gelatin-alginate matrixes in contact with human blood in vitro studies. The percentage of hemolysis and free hemoglobin concentration were normal. The blood recalcyfication time (CT) was shortened and activated partial thromboplastin time (APTT) was prolonged. That sugested that coagulation processes were activated. Discrabed changes were depended an component composition of sponge.     

Hydrogen Bonding Directed Self-Assembly of a Binuclear Ag(I) Metallacycle into a 1D Supramolecular Polymer

An Ag(I) metallacycle obtained unexpectedly during the preparation of Pd(II) complexes of the bifunctional ligand 5-([2,2′-bipyridin]-5-yl)pyrimidine-2-amine (L) has been characterized using X-ray structure determination as a binuclear, metallacyclic species [Ag₂L₂](SbF₆)₂, where both the bipyridine and pyrimidine-N donors of L are involved in coordination to the metal. The full coordination environment of the Ag(I) defines a case of highly irregular 4-coordination. In the crystal, the Ag-metallacycles assemble into one-dimensional supramolecular metalladynamers linked together by hydrogen-bonding interactions.     

Synthesis of 3‐(2‐benzyloxy‐6‐hydroxyphenyl)‐1‐methylpyrazoles by the reaction of chromones with methylhydrazine

The 3‐(2‐benzyloxy‐6‐hydroxyphenyl)‐5‐(methyl, phenyl or styryl)pyrazoles were prepared from the reaction of 2‐(methyl, phenyl or styryl)chromones with methylhydrazine. The structure of these compounds has been determined by several nmr techniques, and the reaction mechanism is discussed.