Pflanzenchemie

Analytical and Bioanalytical Chemistry -     

State-specific reactions and autoionization dynamics of Ar produced by synchrotron radiation

The long-lived excited states of doubly charged rare gases can markedly affect their reactivity. In this paper we demonstrate the presence of strong state-specific effects in the charge exchange of Ar²⁺ (³P, ¹D and ¹S) with several neutral targets (He, Ne, Kr, Xe, D₂, and CH₄). State sensitive measurements have been performed by producing the different Ar²⁺ electronic states via tunable synchrotron radiation (Elettra-Trieste, Italy and SuperACO-Orsay, France). From the product ion yield data of charge transfer, state-selected total cross-sections have been deduced. Using the state-specific reactivity of Ar²⁺ towards different neutral targets, it has been possible to extract the photon-energy-dependent production branching of the three doubly charged states and to investigate the autoionization dynamics of neutral or singly charged Ar in the vicinity of the double ionization threshold.     

The kinetics of oxiranes addition to bis/2-hydroxyalkyl/disulfides and bis/2-hydroxyalkyl/sulfides in the presence of N,N-dimethylcyclohexylamine

Rate constants for the reaction of oxiranes with bis/2-hydroxyalkyl/disulfides, bis/2-Hydroxyalkyl/sulfides, and 1,6-Hexanediol in the presence of N,N-dimethylcyclohexylamine were studied at the temperature range of 50–90°C. A mechanism of these reactions has been proposed and its kinetic equation has been presented.     

Numerical study of the flow in a three-dimensional thermally driven cavity

Solutions for the fully compressible Navier–Stokes equations are presented for the flow and temperature fields in a cubic cavity with large horizontal temperature differences. The ideal-gas approximation for air is assumed and viscosity is computed using Sutherland's law. The three-dimensional case forms an extension of previous studies performed on a two-dimensional square cavity. The influence of imposed boundary conditions in the third dimension is investigated as a numerical experiment. Comparison is made between convergence rates in case of periodic and free-slip boundary conditions. Results with no-slip boundary conditions are presented as well. The effect of the Rayleigh number is studied.     

Über die Niveaukurven logarithmischer Flächenpotentiale

Ohne Zusammenfassung     

A note on monotone paths in labeled graphs

We characterize countable graphs with the property that every one-to-one labeling of edges by positive integers admits a monotone path.