Abstract: We optimized the deposition of YBa2(Cu1-xZnx)(3)O-7-delta thin-films using inverted cylindrical magnetron sputtering and report here a detailed structural study, especially in relation to crystal growth, associated surface morphology, Y2O3 precipitation and other secondary phases important for flux pinning. We find that the epitaxial quality of the Zn-substituted YBa2Cu3O7-delta films is decreased compared with high-quality pure YBa2Cu3O7-delta films prepared under identical conditions. The pure films have smoother surfaces, while those of Zn-substituted films contain pinholes and outgrowths. Secondary phases and a-axis grains were observed in the Zn-substituted films. Y2O3 precipitates with typical dimensions of 50-100 Angstrom have been found in both pure and Zn-substituted samples. However, their density of about 10(23) m(-3), observed in the pure films, is significantly reduced in the Zn-substituted films when increasing the Zn concentration up to 4%.

Abstract: Submicron colloidal Ag particles and nano-sized filaments forming a statistical percolation network during ''in situ'' development of double structure tabular microcrystals of AgRr(I) emulsions have been studied by electron energy-loss spectroscopy and zero-loss electron spectroscopic imaging (EELS/ZLESI). Image analysis has shown that random quasi-fractal clusters were formed in the colloid. ZLESI has been applied to characterise the morphology and defect structure of aggregated particles and filaments. Their energy-loss spectra revealed plasmon excitations and interband 4d electron transitions between 4-32 eV energy-loss. To study the cluster structure and its relation to the physical properties, fractal analysis including estimations of cluster fractal dimensions and of density autocorrelation functions has been performed. Mechanisms of fractal aggregation based on known models of diffusion limited aggregation, cluster-cluster aggregation and percolation are discussed.

Abstract: A two-dimensional model is presented that describes the behavior of argon metastable atoms, copper atoms, and copper ions in an argon direct. current glow discharge, in the standard cell of the VG9000 glow discharge mass spectrometer for analyzing flat samples. The model is combined with a previously developed model for the electrons, argon ions, and atoms in the same cell to obtain an overall picture of the glow discharge, The results of the present model comprise the number densities of the described plasma species, the relative contributions of different production and loss processes for the argon metastable atoms, the thermalization profile of the sputtered copper atoms, the relative importance of the different ionization mechanisms for the copper atoms, the ionization degree of copper, the copper ion-to-argon ion density ratio, and the relative roles of copper ions, argon ions, and atoms in the sputtering process. All these quantities are calculated for a range of voltages and pressures, Moreover, since the sticking coefficient of copper atoms on solid surfaces is not well-known in the literature, the influence of this parameter on the results is briefly discussed.

Abstract: The integration of the nonlinear least squares X-ray spectrum evaluation progam AXIL. into a mu-PIXE and a mu-XRF setup is discussed. The use of the software when procesing data sets derived from biological and geological samples is described.

Abstract: Ca-containing particles, especially CaSO4 particles, have been encountered in several atmospheric aerosol studies. An overview is given of the different sources of airborne Ca-containing particles, The North Sea atmosphere is studied to identify the different Ca-containing particle types and to find the correlation between their occurrence and the source regions of the corresponding air masses. About 50000 individual aerosol samples were collected above the Southern Eight of the North Sea for several wind directions and analyzed for their composition using electron probe X-ray microanalysis. Nonhierarchical cluster analysis is performed on the data to reveal the different particle types, their relative abundances and their sources. CaSO4 in most cases constitutes the largest fraction of the Ca-containing particles. Extremely high numbers of CaSO4 particles are found for northeastern winds, coming from the central part of Germany, suggesting that a great fraction is derived from anthropogenic sources located in this region. Among the other Ca-containing particle types are the aluminosilicates, CaCO3, Fe-Ca-rich particles, and CaSO4 or CaCO3 in combination with NaCl.

Abstract: Aerosol samples have been collected over the southern bight of the North Sea from an aircraft. In this way, 96 samples were taken for single-particle analysis during 16 flights. Almost 45 000 individual particles were analyzed with electron probe X-ray microanalysis. More than 5000 of these were found to contain significant concentrations of one or more of the heavy metals Cr, Pb, and Zn. With the help of hierarchical, nonhierarchical, and fuzzy clustering techniques, various heavy metal-containing particle types could be identified. Significant differences in abundances were detected in the North Sea heavy metal aerosol, depending on the origin of the air masses. In samples with continental influence 50 times more Zn- and Pb-containing particles were found than in samples with a marine history. For Cr, on the other hand, we found abundances in the marine sector that were one-third of the values for continental sectors. This might point to a rather undefined marine source, which could be the recycling of previously deposited material by reinjection into the atmosphere by sea spray. The highest values for Cr-, Pb-, and Zn-containing particles were always detected under southeastern wind directions.