Die Verwendung des Cupferrons in der quantitativen Analyse

Ohne Zusammenfassung Die Zitate zu diesem Referat folgen ausnahmsweise am Schlusse des ganzen Artikels S. 66.     

Generating indecomposable permutations

An indecomposable permutation π on [n] is one such that π([m])=[m] for no m<n. We consider indecomposable permutations and give a new, inclusive enumerative recurrence for them. This recurrence allows us to generate all indecomposable permutations of length n in transposition Gray code order, in constant amortized time (CAT). We also present a CAT generation algorithm for indecomposable permutations which is based on the Johnson-Trotter algorithm for generating all permutations of length n. The question of whether or not there exists an adjacent transposition Gray code for indecomposable permutations remains open.     

The aging of silicate glass surfaces in humid air

Slicate glass surfaces were observed over several weeks in normally humid laboratory air by atomic force microscopy. Auger spectroscopy and lateral force microscopy measurements were also made. Samples in the study include; vitreous quartz, bulk insulation glass, bulk and fibrous textile e-glass, and bulk container glass. Various features developed on these surfaces are consistent with patterns seen in crystal growth from supersaturated solution. Auger spectroscopy reveals the presence of chemically bound carbon and supports the hypothesis that these crystals are alkali and alkali earth carbonate species. The presence of these crystals is expected to affect the bonding of a coating to silicate surfaces.     

BaO/W(1 0 0) thermionic emitters and the effects of Sc, Y, La, and the density functional used in computations

Density functional theory is used to predict workfunctions, φ. For relaxed clean W(1 0 0), the local density approximation (LDA) agrees with experiment better than the newer generalized gradient approximation, probably due to the surface electron self-energy. The large Ba metallic radius indicates it covers W(1 0 0) at about 0.5 monolayer (ML). However, Ba²⁺, O²⁻, and metallic W all have similar radii. Thus 1 ML of BaO (one BaO unit for each two W atoms) produces minimum strain, indicating commensurate interfaces. BaO (1 ML) and Ba (1/2 ML) have the sameφ to within 0.02 V, so at these coverages reduction or oxidation is not important. Due to greater chemical activity of ScO vs. highly ionic BaO, when mixing the latter with this suboxide of scandia, the overlayer always has BaO as the top layer and ScO as the second layer. The BaO/ScO bilayer has a rocksalt structure, suggesting high stability. In the series BaO/ScO/, BaO/YO/, and BaO/LaO/W(1 0 0), the latter has a remarkably low φ of 1.3 V (LDA), but 2 ML of rocksalt BaO also has φ at 1.3 V. We suggest BaO (1 ML) does not exist and that it is worthwhile to attempt the direct synthesis and study of BaO (2 ML) and BaO/LaO.     

Surface infra-red emission during alkali–metal incorporation at an oxide surface

Thermal emission of infra-red radiation from excited vibrational states is a sensitive probe of surface lattice dynamics, allowing the effects of adsorbed species to be studied in unprecedented detail. Here we examine the incorporation of adsorbed K into a NiO surface by following the formation of K₂O₂ and KNiO₂ through the evolution of the phonon spectrum. The resolution attained in the emission experiment yields new insight into processes of interdiffusion and growth. We identify O atoms as the mobile species at annealing temperatures up to 300 K, with K/Ni interdiffusion occurring after annealing at 600 K.