The evolution of magnetic,electrical and structural properties of nanogranular [FeCoBN/SiN]×n thin films

Some results concerning the magnetic, electrical and microstructural properties of multilayer [FeCoBN/Si₃N₄]×n films in view of their utilization for manufacturing thin film magnetic inductors are presented. A comparison between the magnetic, electrical and structural properties of FeCoBN and [FeCoBN/Si₃N₄]×n thin films is also reported. The [FeCoBN/Si₃N₄]×n thin films with the thickness of the FeCoBN layers varied from 10 to 30 nm, exhibit good soft magnetic characteristics and high values for electrical resistivity such as Ms of 172–185 A m²/kg, Hc of 318–1433 A/m and ρ of 82–48×10⁻⁷ Ω m, respectively. These physical properties of the samples are discussed in relation with the microstructure of the multilayer system.     

Comparison of detection efficiencies of negatively charged gold-alkanethiolate-, gold-sulfur- and gold-clusters in ToF-SIMS

In order to improve quantification of high mass ions, the influence of cluster composition on detection efficiencies has been studied using a TOF-SIMS IV with the extended capability of postaccelerating ions up to 20 keV. In this experimental study, we focus on the comparison of detection efficiencies for three types of negatively charged secondary cluster ions: gold-alkanethiolate-clusters (Au_xM_y), gold-sulfur-clusters (Au_xS_y) and gold-clusters (Au_x). The clusters were sputtered from self-assembled monolayers of hexadecanethiols on gold substrates using 10 keV Ar⁺ primary ions. The detection efficiencies were derived on the basis of a function for the secondary electron yield and a fourth-order approximated Poisson probability distribution for electron propagation and amplification within the microchannel plate.In addition to the well-known dependence of detection efficiencies on ion mass and energy, which has already been studied for positively charged ions, we were able to show a similar behaviour for the investigated negatively charged secondary ions. We have observed major variations among the three types of clusters at similar mass and energy as predicted in a theoretical approach. The observed differences are due to the different composition of the investigated clusters which has a major influence on the kinetic ion induced electron emission within the microchannel plate. For the first time it was possible to experimentally verify these predictions for detection efficiencies.     

General synchronization dynamics of coupled Van der Pol–Duffing oscillators

This paper considers the general synchronization dynamics of coupled Van der Pol–Duffing oscillators. The linear and nonlinear stability analysis on the synchronization process is derived through the Whittaker method and the Floquet theory in addition to the multiple time scales method. A stability map displaying different dynamical states of the system is performed. Numerical simulation is carried out to support and to complement the accuracy of the analytical treatment.     

Bäcklund Transformation and N-Soliton Solution for the Generalized Nonlinear Schrödinger Equation

For the generalized nonlinear Schrödinger equation, the N-fold Bäcklund transformation is derived. As particular results, the explicit 1-soliton solution is obtained and the interaction of two solitons is discussed.     

Non-destructive analysis of archeological samples by energy-dispersive X-ray fluorescence

Summary A non-destructive method is described for the determination of major and minor constituents in archeological specimens by energy-dispersive X-ray fluorescence. Homogeneity tests are made by measuring at various sites of the specimen. In the same way, mean values are obtained for inhomogeneous specimen without taking samples. For calibration, powder standards are used. In case of the determination of elements with numbers up to 14 (Si) a vacuum chamber is used and the dimensions of the specimens are limited by the dimensions of that vacuum chamber, whereas for the determination of elements from K up to U specimens of any size, form or weight are suitable.

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Zerstörungsfreie Analyse von archäologischen Proben mit Hilfe der Energie-dispersiven Röntgenfluorescenzanalyse

Zusammenfassung Eine zerstörungsfreie Methode für die Bestimmung von Haupt- und Nebenbestandteilen in archäologischen Proben mit Hilfe der Energie-dispersiven Röntgenfluorescenzanalyse wird beschrieben. Für Homogenitätstests wird an mehreren Stellen der Probe gemessen. In der gleichen Weise werden für inhomogene Proben Mittelwerte erhalten ohne Probenahme. Für die Eichung werden Pulverstandards verwendet. Im Falle der Bestimmung von Elementen mit Ordnungszahlen bis 14 (Si) wird eine Vakuumkammer eingesetzt, und die Dimensionen der Proben sind durch die Dimensionen dieser Vakuumkammer begrenzt, während für die Bestimmung der Elemente K bis U Proben jeder Größe, jeder Form oder jeden Gewichts verwendbar sind.

     

Particle size analysis by sedimentation field flow fractionation. Performance and application

Recently commercial equipment using sedimentation field flow fractionation (SFFF) has become available for analysis of particulate materials in the sub-micron range. This paper describes the DuPont instrument and discusses its performance. A particular study is described on the comparison of the SFFF technique with that of quasi-elastic light scattering (QELS). The paper concludes that the instrument is capable of measuring particle size distributions with high resolution and precision, provided that no particles above the upper size limit — about 1 μm — are present.     

Dynamic percolation in water in oil microemulsions revisited

Microemulsions (dispersions of water droplets, typical radius about 10 nm, in oil) show a particular percolation pattern, a so-called dynamical percolation. Predictions of scaling theory and Monte Carlo simulations were compared with experimental static and frequency dependent conductivity data. The latter gives evidence of two different time scales of charge transport.Dedicated to Professor Harry Thomas on the occasion of his 60th birthday