On the new possibility to describe the time evolution in nuclear collisions at high energies

In this work we give an attempt to introduce a temporal scale for nuclear collisions inspired by the Hubble cosmology and check it for Au+Au collisions at energies of 200 GeV/nucleon characteristic to BRAHMS Collaboration. We also give some correlations with different phenomena.     

Methyl 5-Deoxy-α and β-D-Xylofuranosides

Abstract

Synthesized from D-xylose, methyl 5-deoxy-α-D-xylofuranoside (1) and methyl 5-deoxy-β-D-xylofuranoside (2) were obtained in overall yields of 24 and 26 %, respectively. The key step in the synthesis was the separation of an anomeric mixture on a strong anion exchanger in OH^? form. NMR data and mass spectra of title compounds 1, 2, methyl 2,3-di-O-acetyl-5-deoxy-α-D-xylofuranoside (3), and methyl 2,3-di-O-acetyl-5-deoxy-β-D-xylofuranoside (4) are discussed. The conformations of 1 and 2 were established from the best fit between calculated and experimental coupling constants using Karplus equation.     

Determination of Non-Ionic Surfactants of the Alcohol Polyethoxylate Type by Means of High Temperature Gas Chromatography and Atomic Emission Detection

High temperature gas chromatography (HT-GC) coupled to atomic emission detection (AED) has been applied for the determination of alkyl chain distribution, mole average degree of ethoxylation and weight percent distribution of the corresponding homologues of alcohol ethoxylates without all the actual homologues being available as pure references. Based upon its constant elemental response, the HT-GC-AED system has been evaluated for its applicability to compound independent calibration within the homologous series of the alcohols and alcohol ethoxylates. Discrimination against high molecular weight components by gas chromatography requires conversion to the acetyl or trimethylsilyl derivatives. The latter includes introduction of the hetero atom silicon and thus allows monitoring of the silicon trace. Thus selectivity will be enhanced by excluding detection of compounds which do not react with the derivatization reagent. The method has been validated with the analysis of the technical product Brij 30, consisting of a mixture of alcohol ethoxylates with a vendor-specified mole average degree of ethoxylation of four. The experimental result yields a mole average degree of 4.0 ± 0.1 in the carbon, silicon and oxygen traces.     

Ueber die Sj?qvist'sche Methode zur Bestimmung der freien Salzs?ure im Magensaft

Ohne Zusammenfassung     

Gas-chromatographic determination of traces of <Emphasis Type="Italic">O</Emphasis>-isopropyl methylphosphonofluoridate (sarin) in soils using its diastereomers

A procedure was developed for determining traces of O-isopropyl methylphosphonofluoridate (sarin) in soils at a level of 2 × 10⁻⁴ mg/kg. The procedure is based on solvent extraction with a hexane-benzene mixture, the preconcentration of the extract to a small volume, the synthesis of dialkyl esters using secondary alcohol aluminates, and gas-chromatographic separation on an HP-1 column with a flame ionization detector. The determination error does not exceed 29%; the time of analysis is 1 h.