The characterization of poorly chrystalline Si-containing natural iron oxides by Mössbauer spectroscopy

Soils developed from recent basalts of Marion Island in the Sub-Antarctic contain about 20% of a poorly crystalline iron oxide. The association of this phase with Al and Si appears to have a major influence on its Mössbauer spectra: whereas room-temperature spectra indicate a relatively regular structure, the magnetic hyperfine fields at 4.2K are lower than those of even the most poorly crystalline pure ferrihydrites.     

Bistellare Äquivalenz kombinatorischer Mannigfaltigkeiten

Ohne Zusammenfassung     

Über isotherme Kurvenscharen vorgegebenen topologischen Verlaufes und ein zugehöriges Extremalproblem der konformen Abbildung

Ohne Zusammenfassung     

Membrane rectification columns for gas separation and determination of the operating lines using the mccabe—thiele diagram

A new continuously operating separating unit — a membrane rectification column — has been developed for the separation of gases by membranes. The membrane rectification column can be characterized as a “step-by-step separating process”. In this article the equations for the operating lines have been constructed to show the separating process with the new enrichment technique in the McCabe—Thiele diagram.