Localized Frames Are Finite Unions of Riesz Sequences

It is shown that every localized frame is a finite union of Riesz sequences. This is a partial solution to a question of Feichtinger.     

A study of the Xαβ-exchange approximation on atoms for use in molecular and solid-state calculations

The Xαβ exchange approximation is applied to atoms and its universal (Z-independent) character is demonstrated. Its practical applicability to molecules and solids is critically analysed by a comparison with the Xα- and HF approximations. The influence of the modifying function which is needed to make the exchange inhomogeneity correction (β-term) finite for large r is studied. The validity of the virial theorem is discussed.     

l-Platte Funktionen auf semianalytischen Mengen

Ohne Zusammenfassung     

Gaseous Fuel Reactor Research

Gaseous Fuel Nuclear Reactors are externally moderated and contain the fissile material inside a cavity where it is suspended by fluid mechanics forces. The gaseous phase of the nuclear fuel permits operation of the reactor at temperatures much higher than the melting point of all materials. NASA has originally supported relevant research for space propulsion. The continuation of this work includes now research on power generation on Earth for improved economy and environmental acceptability. In reactor experiments with enriched uranium hexafluoride, UF6, a critical mass of 6 kg is determined. Pressurized UF6 remains chemically stable at temperatures up to 2000 kelvins. The interaction of fission fragments with their gaseous environment causes preferential excitation and ionization, leading to non-equilibrium optical radiation. Powerful fluxes of photons are expected to become a superior mechanism of energy extraction from the fissioning gas or plasma in the reactor. The pumping of lasers solely by fission fragments is realized in a variety of lasants. A near term objective of the NASA gaseous fuel reactor program is a benchmark experiment at 100 kw power and at a gas temperature of 1600 kelvins, demonstrating the feasibility of major advances in reactor technology. A concerted research effort is leading to this experiment. A plasma core cavity reactor for high specific impulse propulsion in space reminas a long range goal.     

W-Gleitgleitkinematik

The following gives some starting elements of a theory, which the author calls glide-glide-kinematics and which goes far beyond the kinematics of helical motion in ℝ ⁿ , which was studied up to now. We are mainly concerned here with “angle-preservering glide-glide-kinematics”, generalising (and giving as well some idea of) the distance-preservering glide-glide-kinematics, which we develop in a forthcoming book ([5]) in detail.      

An SCF-Xα-SW study of the ionic and covalent state in the NaCl System

The reference level of the separated constituents and the crossing of the potential curves for the ionic and covalent state are discussed with respect to the choice of orbital occupation numbers and Fermi-Dirac statistics. Calculations show a distinct crossing of potentials curves, when using a constraint of integer occupation numbers. No crossing is predicted, when fractional occuption numbers are used, which are adjusted according to Fermi-Dirac statistics.[/p]