Kinetic Description of the Stationary Band-Like Weakly Turbulent Beam Discharge Plasma in Hydrogen. I. Basic Equations — Numerical Approach — Ionization and Dissociation Budget

On the basis of the electron Boltzmann equation and of the balances for the charge carriers (e, H⁺, H₂⁺, H₃⁺), the H-atoms and the metastable H(2s)-atoms for the H/H₂-mixture the behaviour of the weakly turbulent, band-like electron-beam discharge plasma in hydrogen has been calculated taking into account the main collision and transport processes. In dependence of the normalized discharge length, the life time of the neutral particles in the band-like plasma and the electron beam generated turbulence energy density the ionization and dissociation budget and in particular the most important electron-heavy particle collision rates, which appear in the balance equation system, are investigated in the present part of our paper. In a second part the results related to the budget of the ions and the metastable atomic state will be reported and an analysis of the main processes in the balances will be made.     

Application of genetic algorithms in molecular modeling

A genetic algorithm has been developed for molecular mechanics calculations. It has been proved to be a robust and efficient structure optimization technique. Because it uses randomly generated starting structures and stochastic operators, the resulting structures are not subjected to the chemist's bias. © 1994 by John Wiley & Sons, Inc.     

Strategy for the synthesis of multivalent peptide-based nonsymmetric dendrimers by native chemical ligation

A strategy for the synthesis of multivalent peptide-based nonsymmetric dendrimers by native chemical ligation using poly(lysine) dendritic wedges as scaffolds is presented.     

Classical bifurcation at the transition from Rabi to Josephson dynamics

We report on the experimental demonstration of the internal bosonic Josephson effect in a rubidium spinor Bose-Einstein condensate. The measurement of the full time dynamics in phase space allows the characterization of the theoretically predicted π-phase modes and quantitatively confirms analytical predictions, revealing a classical bifurcation. Our results suggest that this system is a model system which can be tuned from classical to the quantum regime and thus is an important step towards the experimental investigation of entanglement generation close to critical points.     

Shear viscosity and spin sum rules in strongly interacting Fermi gases

Fermi gases with short-range interactions are ubiquitous in ultracold atomic systems. In the absence of spin-flipping processes the number of atoms in each spin species is conserved separately, and we discuss the associated Ward identities. For contact interactions the spin conductivity spectral function σ_s(ω) has universal power-law tails at high frequency. We derive the spin f-sum rule and show that it is not affected by these tails in d < 4 dimensions. Likewise the shear viscosity spectral function η(ω) has universal tails; in contrast they modify the viscosity sum rule in a characteristic way.     

An approach to account for interfering parametric resonances and anti-resonances applied to examples from rotor dynamics

Nonlinear Dynamics - An initially unstable equilibrium position of a system can be stabilized by introducing a parametric excitation. This is especially of interest for suppressing self-excited...     

Einstein’s working sheets and his search for a unified field theory

The European Physical Journal H - The Einstein Archives contain a considerable collection of calculations in the form of working sheets and scratch paper, documenting Einstein’s scientific...