Zur Elektroanalyse von nickelhaltigen Bronzen und Aluminium Leichtmetall-Legierungen

Ohne Zusammenfassung     

Thermal degradation of copolymers of methyl methacrylate and methyl acrylate. I. Products and general characteristics of the reaction

The technique of thermal volatilization analysis (TVA), applied to methyl methacrylate–methyl acrylate copolymers having molar composition ratios 112/1, 26/1, 7.7/1, and 2/1, has demonstrated that the stabilization of poly(methyl methacrylate) by copolymerized methyl acrylate is due to inhibition of the depolymerization initiated at terminally unsaturated structures, probably by direct blockage by methyl acrylate units. The molecular weight of the copolymers decreases rapidly during degradation, suggesting that a random scission process is involved. The products of degradation consist of the monomers, carbon dioxide, chain fragments larger than monomer, and a permanent gas fraction which is principally hydrogen. Infrared and ultraviolet spectral measurements suggest that the residual polymer, which is colored, incorporates carbon–carbon unsaturation. The complete absence of methanol among the products is surprising in view of its abundance among the products of degradation of poly(methyl acrylate). These observations have been accounted for qualitatively in terms of acceptable polymer behavior.     

Multiple specific heat anomalies at the neutral-ionic phase transition in TTF-chloranil

The specific heat has been measured for the mixed stack organic compound TTF-chloranil from 10 to 300K. Both protonated and deuterated samples exhibited a large specific heat anomaly in the region of the Neutral-Ionic phase transition near 84K. This anomaly has a very peculiar form, composed of a number of sharp peaks. In one sample, three very sharp, symmetric peaks were observed. Based on these specific heat data alone, it is difficult to determine the order of the phase transition. Complimentary measurements, however, that combine differential thermal analysis and cycling, appear to rule out a simple first order phase transition. Significant and uncontrolled changes in c_p of unknown origin are observed and prevent a more quantitative analysis of the data.     

Relationship of crystal growth parameters to the stoichiometry of EuO as determined by I.R. and conductivity measurements

Single crystals of EuO have been grown from melts containing excess Eu-metal. i.r. absorption and conductivity measurements were made on these crystals and the results correlated with the crystal growth parameters. It is seen that as the concentration of europium in the initial melt is increased, the growth temperature is lowered and the crystals become richer in europium. The variations in the i.r. absorption and conductivity were studied and are shown to be strongly related to composition. According to the i.r. and conductivity behavior, the EuO crystals can be classified into five types, with compositions ranging from oxygen-rich, to stoichiometric, to europium-rich. The oxygen-rich EuO crystals are insulators and exhibit i.r. absorption which is attributed to Eu₃O₄ and to Eu³⁺. Only weak i.r. absorption is seen in the stoichiometric crystals. Those with a deficiency of oxygen show a new i.r. absorption and have either metallic conduction or show large insulator-metal transitions which are attributed to oxygen vacancies.     

The application of high resolution two-dimensional polyacrylamide gel electrophoresis to the identification and purification of a protein, NG8.4, present in Neisseria gonorrhoea and the subsequent development of a radioimmunoassay

A soluble protein of unknown function was shown, by two-dimensional polyacrylamide gel electrophoresis, to be present in Neisseria gonorrhoeae at significantly higher concentrations than in the other related bacteria tested. The data indicate the possibility of this protein being specific to Neisseria gonorrhoeae. This protein was designated as NG 8.4 and purified. A radioimmunoassay was developed for the measurement of this protein and subsequently used to determine the degree of cross reaction exhibited by a number of species of bacteria. Of the bacteria tested only those of the genus Neisseria gave a significant reaction in the assay.