Real-space measurement of the potential distribution inside organic semiconductors

We demonstrate that the soft nature of organic semiconductors can be exploited to directly measure the potential distribution inside such an organic layer by scanning-tunneling microscope (STM) based spectroscopy. Keeping the STM feedback system active while reducing the tip-sample bias forces the tip to penetrate the organic layer. From an analysis of the injection and bulk transport processes it follows that the tip height versus bias trace obtained in this way directly reflects the potential distribution in the organic layer.     

Biased Diffusion with Correlated Noise

The diffusion of hard-core particles subject to a global bias is described by a nonlinear, anisotropic generalization of the diffusion equation with conserved, local noise. Using renormalization group techniques, we analyze the effect of an additional noise term, with spatially long-ranged correlations, on the long-time, long-wavelength behavior of this model. Above an upper critical dimension d _LR, the long-ranged noise is always relevant. In contrast, for d<d _LR, we find a weak noise regime dominated by short-range noise. As the range of the noise correlations increases, an intricate sequence of stability exchanges between different fixed points of the renormalization group occurs. Both smooth and discontinuous crossovers between the associated universality classes are observed, reflected in the scaling exponents. We discuss the necessary techniques in some detail since they are applicable to a much wider range of problems.     

Onsager-Zerlegung und Entropieproduktion für einen Defektspin in der linearen Spinkette mitX-Y-Kopplung

The autocorrelation function of an impurity spin in an infinite chain of spins withX-Y-coupling in thermal equilibrium is shown to be an example of “Onsager separation”. This separability ensures that the statistical entropy production associated with the impurity spin relaxation contains a phenomenological part which proves to be always positive.     

Mass spectrometry-gas chromatographic determination of mecloqualone metabolites from urine extracts

Summary The separation and identification of metabolites of mecloqualone in human urine samples by GLC-MS analysis are described. Four hydroxylated mecloqualone derivates have been identified.

---

Zusammenfassung Die Trennung und Identifizierung von Metaboliten des Mecloqualons in Menschenharn durch Gas-Flüssigchromatographie und Massenspektrometrie wurde beschrieben. Vier Hydroxylderivate des Mecloqualons wurden identifiziert.

     

A comparative study of single crystal magnesium oxide and oxidised magnesium by auger electron spectroscopy

In a study by AES of the surfaces of single crystal magnesium oxide and magnesium after various stages of oxidation, it has been shown that Auger energy shifts are produced by surface charging. Recognition of the charging effects has enabled the peak in the low energy spectrum of magnesium oxide crystal to be assigned. The low energy secondary electron spectra of both MgO crystal and oxidised magnesium are complicated by the presence of extra features which arise from diffraction of true secondary electrons, and in particular for oxidised magnesium a cross-transition occurring at the metal-oxide interface. Oxidation studies of sodium also reveal transitions arising from a similar process.     

Die Struktur endlicher schwach abgeschlossener Jordanalgebren Teil I. Stetige Jordanalgebren

On the basis of the authors previous paper [6] the properties of the lattice of idempotents in a finite weakly closed Jordan algebra A are examined. The results then yield a unique direct decomposition A=A_d⊕A_c where A_d is a discrete and A_c is a continuous Jordan algebra. An application of Jacobsons coordinatization theorem shows A_c=H(D), D associative, since there exist sufficiently many strongly connected idempotents. Then we prove that D is a uniquely determined continuous real W^* -algebra with finite normal faithful trace.     

Fluktuationen von Besetzungszahlen

Kinetic equations for the fluctuations and the fluctuation spectrum of the occupation numbers in a nonequilibrium stationary state are derived within a stochastic theory. The probability of changes of the distribution in infinitesimal time intervals is given by the “Stoßzahlansatz”. It is assumed for the decoupling of the higher correlations, that the occupation numbers are macroscopic variables.     

Low energy Auger and loss electron spectra from magnesium and its oxide

Data have been obtained from Auger and energy loss processes in clean metallic Mg, Mg during stages of oxidation, and UHV cleaved MgO(100) surfaces. Particular attention has been paid to twenty features below 200 eV in the Auger spectra from these surfaces. A comparison of spectra from the metal, oxidised metal surface, and single crystal MgO has enabled estimates to be made of surface charging effects, and the MgO steady state surface potential is found to be near + 10 V above ground. All the Auger features are given assignments, two of which are interfacial processes involving ionic initial states and metallic final states. Several features in the low energy Auger spectrum are attributed to diffraction of true secondary electrons.