Analysis of alkyl polyglucosides in industrial products by capillary electrophoresis with pulsed amperometric detection

Pulsed amperometric detection following micellar electrokinetic chromatography has been applied successfully to the direct detection of alkyl polyglucosides (APGs) in shampoos and other industrial products without prior conversion to highly absorbing or fluorescing derivatives. For electrochemical detection, it is necessary to dissociate the hydroxyl groups of the APGs. Thus, we used 0.1 M NaOH in the outlet vial to dissociate the APGs. The main problems associated with the combination of electrochemical detection and capillary electrophoresis are the need to isolate the detector from the electric field used in the capillary electrophoresis separation and the difficulty of aligning the working electrode with the end of the capillary. To overcome these problems, a simple capillary-electrode holder was constructed. This holder automatically aligns the capillary and the electrode in a wall-jet configuration without the aid of micropositioners and facilitates the replacement of electrodes and capillaries without reconstruction of the entire capillary/electrode setup. Special microcylindrical gold electrodes have been produced by sealing 300-μm-diameter gold wire into borosilicate-glass capillaries.     

Predicted ultrafast dynamic metallization of dielectric nanofilms by strong single-cycle optical fields

We predict a dynamic metallization effect where an ultrafast (single-cycle) optical pulse with a ?1 V/? field causes plasmonic metal-like behavior of a dielectric film with a few-nm thickness. This manifests itself in plasmonic oscillations of polarization and a significant population of the conduction band evolving on a ~1 fs time scale. These phenomena are due to a combination of both adiabatic (reversible) and diabatic (for practical purposes irreversible) pathways.     

Effects of multi orbital contributions in the angular-dependent ionization of molecules in intense few-cycle laser pulses

We outline the details of our new method to calculate angular-dependent ionization probabilities based on electronic structure theory for diatomic and larger systems. To demonstrate its abilities, we compare our calculations to measured ionization probabilities of the four molecules D₂, N₂, O₂ and CO in the strong-field regime. The calculated angular distributions yield better agreement with the experimental data than those obtained from the widely used MO-ADK theory. For CO the measured angular distributions of ionic fragments indicate contributions to the ionization from both the HOMO and the HOMO-1 orbital, an effect that is addressed by the theory.     

Buchbesprechungen

Ohne Zusammenfassung     

Magnetic characterization of ZnO doped with vanadium

The magnetic properties of vanadium doped ZnO nanorods formed by different growth methods were examined. The samples under investigation were either grown by metallorganic vapour-phase epitaxy (MOVPE) with in situ incorporation of the V atoms or by aqueous chemical growth (ACG) in combination with an ion-implantation process. The V concentration for all samples was less than 2 at.%.Field-cooled SQUID measurements only reveal a weak ferromagnetic signal still in a very sensitive measuring range. However, the MFM micrographs obtained at room temperature show a clear magnetic contrast and complex structures, the images are in good agreement with the phase images expected for vertically aligned magnetic dipoles. This is a strong indication for a ferromagnetic behaviour at room temperature.     

Calorimetrie

Ohne Zusammenfassung     

Milch

Ohne Zusammenfassung