Zur Bestimmung von Kohlenstoff durch Oxydation mit Chroms?ure

Ohne Zusammenfassung     

Formation and characterization of fluid lipid bilayers on alumina

Fluid lipid bilayers were deposited on alumina substrates with the use of bubble collapse deposition (BCD). Previous studies using vesicle rupture have required the use of charged lipids or surface functionalization to induce bilayer formation on alumina, but these modifications are not necessary with BCD. Photobleaching experiments reveal that the diffusion coefficient of POPC on alumina is 0.6 microm (2)/s, which is much lower than the 1.4-2.0 microm (2)/s reported on silica. Systematically accounting for roughness, immobile regions and membrane viscosity shows that pinning sites account for about half of this drop in diffusivity. The remainder of the difference is attributed to a more tightly bound water state on the alumina surface, which induces a larger drag on the bilayer.     

Semiquantitative analyses by secondary ion mass spectrometry using one fitting parameter

Summary A procedure for SIMS semiquantitative analysis, based on the use of one fitting-parameter, has been applied to metal and mineral standards with satisfactory results. Values of this parameter for various matrices are given, and prospects for analyses involving no reference elements are discussed. Analytical accuracies obtainable for individual elements are assessed in terms of matrix-independent error factors.

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Zusammenfassung Eine Methode zur semiquantitativen SIMS-Analyse, die im Gegensatz zu den aus der Literatur bekannten Verfahren nur einen Anpassungsparameter benötigt, wurde mit gutem Erfolg an Metall- und Mineralstandards getestet. Werte des Anpassungsparameters für verschiedene Matrices wurden angegeben und Aussichten für eine Weiterentwicklung dieser Methode in Richtung auf standardfreie Analysen wurden besprochen. Die analytische Richtigkeit für einige Elemente wurde mit Hilfe von matrixunabhängigen Fehlerfaktoren abgeschätzt.

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Presented at the International Symposium on Microchemical Techniques 1977, Davos, May 1977.     

A mean reverting process for pricing treasury bills and futures contracts

An analytically tractable, discrete-time single-factor model is developed for valuing treasury bills and futures contracts. It uses a multiplicative binomial foward process that creates neither negative nor implausibly large positive interest factors, and which can incorporate different possible degrees of mean reversion. The paper derives explicit formulae for bill prices, futures prices, their conditional variances and risk premia in a setting that relates the evolution of the term structure more closely to both model and data than do other similar works. In contrast to other term-structure constrained models, this paper emphasizes that in a one-factor model the martingale probabilities cannot be treated independently of the perturbation functions. The paper's empirical methods also differ from the customary approaches. Instead of comparing differences between model-predicted and observed prices, the paper applies ARCH methodology to test model-predicted ratios of conditional variances to risk premia. Our tests find influences exogenous to the model, but these factors do not seem capable of being explained with two-factor models using only interest rates.     

Optical DE/MUX Components for Datacomunication Applications

This paper reviews the potential for WDM systems to be implemented within datacommunication systems, and indicates future network functions. Spectral and temporal multiplexing functions are reviewed, with particular focus being placed on 2DIO and amplifier based crosspoint components.     

Born Reciprocity and the Granularity of Spacetime

The Schrödinger-Robertson inequality for relativistic position and momentum operators X ^μ, P _ν, μ, ν = 0, 1, 2, 3, is interpreted in terms of Born reciprocity and ‘non-commutative’ relativistic position-momentum space geometry. For states which saturate the Schrödinger-Robertson inequality, a typology of semiclassical limits is pointed out, characterised by the orbit structure within its unitary irreducible representations, of the full invariance group of Born reciprocity, the so-called ‘quaplectic’ group U(3, 1) #x2297;_s H(3, 1) (the semi-direct product of the unitary relativistic dynamical symmetry U(3, 1) with the Weyl-Heisenberg group H(3, 1)). The example of the ‘scalar’ case, namely the relativistic oscillator, and associated multimode squeezed states, is treated in detail. In this case, it is suggested that the semiclassical limit corresponds to the separate emergence of spacetime and matter, in the form of the stress-energy tensor, and the quadrupole tensor, which are in general reciprocally equivalent.