Bulk and surface properties of liquid Al-Mg, Au-Sn, and Mg-Tl compound forming alloys

We have used phenomenological models based on statistical mechanics to study the bulk and surface properties of Au-Sn, Al-Mg, and Mg-Tl binary liquid alloys. Our study reveals that the three alloys are weakly ordered systems with the most stable intermetallic complexes at temperatures of 823 K, 1073 K and 923 K been AuSn, Al₃Mg₂ and Mg₄Tl, respectively. An analysis of Warren-Cowley short-range order parameter indicates that the weakest intermetallic compound is Al-Mg while Au-Sn is observed to be more chemically ordered than Mg-Tl. Furthermore, our surface properties calculations shows that Mg-atom and Sn-atom segregate to the surface over the whole concentration range of Al-Mg and Au-Sn alloys, respectively. In Mg-Tl, there is a competing effect between Tl-atom being drawn into the bulk and at the same time Tl-atom wanting to segregate to the surface over the whole concentration range.     

Thermodynamic properties of some gallium-based binary alloys

We have studied the concentration dependence of the free energy of mixing, concentration-concentration fluctuations in the long-wavelength limit, the chemical short-range order parameter, the enthalpy and entropy of mixing of Ga-Zn, Ga-Mg and Al-Ga binary alloys at different temperatures using a quasi-chemical approximation for compound forming binary alloys and that for simple regular alloys. From the study of the thermodynamic quantities, we observed that thermodynamic properties of Ga-Zn and Al-Ga exhibit positive deviations from Raoultian behaviour, while Ga-Mg exhibits negative deviation. Hence, this study reveals that both Ga-Zn and Al-Ga are segregating systems, while chemical order exists in Ga-Mg alloy in the whole concentration range. Furthermore, our investigation indicate that Al-Ga binary alloy have a tendency to exhibit ideal mixture behaviour in the concentration range 0?c_Al?0.30 and 0.7?c_Al?1.     

Zur Bestimmung des Zinks in der forensischen Analyse

Ohne Zusammenfassung     

Correlation between bulk and surface properties in Cd–X (X = Hg,Mg) liquid alloys

A theoretical investigation of the energetics and its effect on the alloying behaviour of Cd–Hg and Cd–Mg liquid alloys have been carried out with the aim of correlating their bulk and surface phenomena. Using the Quasi-chemical approximation for regular solution model, our results indicate that Cd–Hg and Cd–Mg are weakly heterocoordinated both in the bulk and on the surface. We observed that the degree of chemical order in Cd–Mg liquid alloy is more than that of Cd–Hg liquid alloy.     

Mit der Bestimmung des Jod- und Kaliumjodidgehaltes in Jodtinktur

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Synthese und HOFMANN-Abbau des 1-(Diphenyl-hydroxymethyl)-2,2-dimethyl-6,7-dimethoxy-1,2,3,4-tetrahydroisochinolinium-Ions

The synthesis of the N-quaternary aminoalcohol 6 is described. Analogous to the aminoalcohols 1 and 2 , 6 on treatment with alkali undergoes fission of the substituent at C(1) as a carbonyl compound, with formation of a N, N-dimethyl-1,2,3,4-tetrahydroisoquinolinium ion, which is further degraded to the corresponding o-vinyl-benzylamine (Scheme1). – As a by-product of a Bischler-Napieralski ring closure, we observed chlorination of an aromatic ring (yielding 19 ).     

Pharmazeutische Pr?parate

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