Bestimmung von Blei in Erzen

Ohne ZusammenfassungAus dem Englischen übersetzt von der Redaction.     

Editor’s Introduction to Jean van Heijenoort, Historical Development of Modern Logic

Van Heijenoort??s account of the historical development of modern logic was composed in 1974 and first published in 1992 with an introduction by his former student. What follows is a new edition with a revised and expanded introduction and additional notes.     

Interaction of urea with poly(2-hydroxyethyl methacrylate) hydrogels

The interaction of poly(2-hydroxyethyl methacrylate) [poly(HEMA)] and other similar hydrogels with dilute urea solution has been studied by a variety of techniques, including swelling experiments, fluorescence quenching, near infrared spectroscopy and fundamental band infrared spectroscopy. The results obtained indicate that the anomalous swelling behavior of poly(HEMA) gels in the presence of such dilute urea solutions is probably not due to the disruption of a secondary hydrophobic bond structure as has been generally believed. Although poly(HEMA) gels do contain sites that can participate in hydrophobic bonding, the evidence gathered indicates that dilute urea solutions have no effect on such bonds. A plausible model that does fit all the data involves the interaction of urea with a secondary structure composed of hydrogen-bonded hydroxyl groups, stabilized by the exclusion of water molecules from the regions containing the bonds.     

Spatial resonances and superposition patterns in a reaction-diffusion model with interacting Turing modes

Spatial resonances leading to superlattice hexagonal patterns, known as "black-eyes," and superposition patterns combining stripes and/or spots are studied in a reaction-diffusion model of two interacting Turing modes with different wavelengths. A three-phase oscillatory interlacing hexagonal lattice pattern is also found, and its appearance is attributed to resonance between a Turing mode and its subharmonic.     

Service stage Petri net models with product form solution

A class of service stage Petri net models whose equilibrium probabilities satisfy local balance equations is presented. Examples of their applicability include bus oriented multiprocessor interconnections, the classical dining philosophers problem and the alternating bit protocol. The natural topological space for embedding the state transition lattice for this class of SSPN is shown to be a multidimensional toroidal manifold.     

Über einige neue Methoden zur Untersuchung von monomolekularen Filmen

Ohne Zusammenfassung