Filtern
Dokumenttyp
Schlagworte
- Alumina (1)
- Analyse (1)
- Coating (1)
- Explosives (1)
- Extraktion (1)
- Gaschromatographie (1)
- Hochdruckflüssigchromatographie (1)
- Holz (1)
- NEXAFS (1)
- Permethrin (1)
Vergleichsanalysen zur Bestimmung von Permethrin aus Holz ergaben, dass sich sowohl Extraktion mit Methanol im Ultraschallverfahren als auch Soxhlet-Extraktion mit Ethylacetat gut eignen, um Permethrin aus behandeltem Holz zu lösen. Verschiedene andere Extraktionsverfahren führen zu Minderbefunden. Zur quantitativen Bestimmung von Permethrin können sowohl Hochdruckflüssigchromatographie als auch Gaschromatographie eingesetzt werden.
The aluminium oxide films on austenitic steel are prepared from sols of re-dispersed boehmite nano powders in water. After dip-coating of the sol, a heat treatment including drying, calcination and annealing in vacuum at temperatures up to 1100°C is performed to obtain crack-free coatings of a thickness up to 6 µm. XRD measurements detect α- and γ-alumina, a TiOx-phase at the metal/coating interface and a gradient of phase formation in the coating. The strong adhesion on the substrates is due to the layered assembly and gradient composition of the coating caused by an inter-diffusion of metal cations and oxygen in the metal/oxide interface during heat treatment. Residual stress measurements by X-rays result in compressive stresses of 24 GPa in the alumina coatings. The pin-on-disc test shows a remarkable improvement of wear resistance obtained by sol-gel coatings. The α-alumina content and the compressive stress of the coatings correlate with wear resistance of the coatings.
The photoinduced pseudorotaxane formation between a photoresponsive axle and a tetralactam macrocycle was investigated in solution and on glass surfaces with immobilized multilayers of macrocycles. In the course of this reaction, a novel photoswitchable binding station with azobenzene as the photoswitchable unit and diketopiperazine as the binding station was synthesized and studied by NMR and UV/Vis spectroscopy. Glass surfaces have been functionalized with pyridine-terminated SAMs and subsequently withmultilayers of macrocycles through layer-by-layer self assembly.
A preferred orientation of the macrocycles could be confirmed by NEXAFS spectroscopy. The photocontrolled Deposition of the axle into the surface-bound macrocycle-multilayers was monitored by UV/Vis spectroscopy and led to an increase of the molecular order, as indicated by more substantial linear dichroism effects in angle-resolved NEXAFS spectra.