Schwefel- und Phosphorbestimmung

Ohne Zusammenfassung     

Determination of the Nitrogen Content of Cationic Cellulose Fibers by Analytical Pyrolysis

 Analytical pyrolysis in combination with gas chromatography and mass spectrometry or a nitrogen-phosphorus detector, respectively, were used to characterize the quaternization reagent glycidyltrimethylammonium chloride and a cationic cotton fabric. Trimethylamine was shown to be the most abundant nitrogen-containing product in the pyrolysis of glycidyltrimethylammonium chloride and was thus used for the quantification of the nitrogen content of the cationic cotton fabric. The results were compared to those obtained by traditional methods such as Kjeldahl and elemental analysis. It could be shown that pyrolysis is well suited for monitoring the nitrogen content of cellulose fibers.     

Cycloaddition of allylsilanes. Part 20: Organosilicon-mediated total synthesis of (±)-cameroonanol

We describe a seven-step total synthesis of the triquinane sesquiterpene (±)-cameroonanol using a Lewis acid-promoted [3+2] cycloaddition of an allylsilane and a modified Fleming-Tamao oxidation as key reactions.     

Tunneling of the Closed Friedmann Universe with Generation of Scalar Waves

The evolution of the closed Friedmann Universe with a packet of short scalar waves is considered with the help of the Wheeler–DeWitt equation. The packet ensures conservation of homogeneity and isotropy of the metric on average. It is shown that during tunneling the amplitudes of short waves of a scalar field can increase catastrophically promptly if their influence to the metric is not taken into account. This effect is similar to the Rubakov-effect of catastrophic particle creation calculated already in 1984.In our approach to the problem it is possible to consider a self-consistent dynamics of the expansion of the Universe and amplification of short waves. It results in a decrease of the barrier and interruption of of amplification of waves, and we get an exit of the wave function from the quantum to the classically available region.     

Bemerkung zur Potentialtheorie

Ohne Zusammenfassung