Longitudinal-transverse interference structure function in the reaction2H(e,e′ p)

The longitudinal-transverse interference structure functionf ₀₁ has been measured in deuterium electrodisintegration experiments at various values of the four-momentum transferQ ². Data taken at different laboratories and at roughly the same value ofQ ² are shown to be consistent. When compared to non-relativistic impulse-approximation calculations mostf ₀₁ data show an enhancement. A relativistic treatment of the reaction²H(e, e p) removes the discrepancy. More definite evidence for relativistic effects in deuterium electrodisintegration can be obtained at higher values of the recoil momentum. The experimental implications for such²H(e, e p) experiments are discussed as well.Dedicated to Prof. Werner Sandhas on the occasion of his 60th birthday     

Temperature measurements in CO2-laser-induced pyrolysis flames for SiC and ternary SiC/C/B powder synthesis by means of CARS

The hot luminescent reaction zones of CO₂-laser-induced pyrolysis flames using SiH₄/C₂H₂ gas mixtures with different silane to acetylene ratios and with and without diborane additives were investigated by means of H₂ Q-branch CARS spectroscopy, leading to spatial temperature profiles in gas flow direction. In the case of B₂H₆ additive to the stoichiometric SiH₄/C₂H₂ mixture a high temperature plateau ( 800–1000 K) of the reactant gas volume develops already several millimetres before reaching the CO₂-laser focus line. This precursor preheating zone could be explained by the catalytic effect of boron atoms or boron-containing intermediate species in the flame. A similar behaviour for acetylene-rich flames operating at half laser power was not observed.     

Study of a glassy carbon electrode in amperometric detection using d.c., normal and differential pulse techniques

The results of a comparative study on d.c., normal pulse and differential pulse techniques applied to anodic amperometric detection at a glassy carbon electrode in a voltammetric flow-through cell are presented. The important aspects examined are response time, linearity, limit of detection and selectivity. It is shown that the d.c. mode is the most favourable as long as no adsorption of oxidation products takes place. If strong adsorption occurs, normal pulse detection is recommended, although the limit of detection is somewhat larger.     

Cluster aggregation: a new method for producing atomic and molecular clusters

A new method for the production of cold free clusters is presented. A beam of large rare gas clusters is passed through a low pressure atomic gas. The gas atoms are picked up by the rare gas clusters whereby they condense. A complete evaporation of rare gas atoms from the newly formed clusters then follows once the number of captured particles becomes sufficiently large. The method is demonstrated for Xe clusters with size up to 500 atoms per cluster but it should work for most materials, including the refractory materials.     

Determination of total sulphur in coal by x-ray fluorescence spectrometry

A precise x-ray fluorescence method for the determination of sulphur in coat. The sample is mixed with calcium oxide and active carbon and is gradually heated to 900°C. After coding, lithium tetraborate and lead oxide are added and a prepared. The Pb M_α line is used as an internal standard for the KK_α line. The results for coal have a relative standard deviation of approximately 1% and exhibit.     

Zur Synthese sulfonierter Derivate von 2-Amino-p-xylol

Synthese of sulfonated derivatives of 2-amino-p-xylene Sulfonation of 2-amino-p-xylene (2) gave 2-amino-p-xylene-5-sulfonic acid (1) . The 2-amino-p-xylene-6-sulfonic acid (3) was prepared via three routes: (1) sulfonation of 2-amino-5-chloro-p-xylene (19) to 5-amino-2-chloro-p-xylene-3-sulfonic acid (20) followed by hydrogenolysis; (2) sulfur dioxide treatment of the diazonium salt derived from 2-amino-6-nitro-p-xylene (21) to 2-nitro-p-xylene-6-sulfonyl chloride (11) followed by hydrolysis to 2-nitro-p-xylene-6-sulfonic acid (4) and Béchamp reduction; (3) Béchamp reduction of 2-chloro-3-nitro-p-xylene-5-sulfonic acid (13) to 3-amino-2-chloro-p-xylene-5-sulfonic acid (16) and subsequent hydrogenolysis. Catalytic reduction of 13 in aqueous sodium carbonate solution gave mixtures of 3 and 16 . 2-Amino-p-xylene-3-sulfonic acid (27) was synthesized via two routes: (1) reaction of 19 with sulfamic acid to 2-amino-5-chloro-p-xylene-3-sulfonic acid (26) followed by hydrogenolysis; (2) sulfur dioxide treatment of the diazonium salt derived from 2-amino-3-nitro-p-xylene (28) to 2-nitro-p-xylene-3-sulfonyl chloride (12) , hydrolysis to 2-nitro-p-xylene-3-sulfonic acid (7) and Béchamp reduction.