New AlDy(Ni,Co) glasses - the influence of pre-aging on decomposition and modelling of the crystallisation

The decomposition of AlDy₆Ni₁₀ and AlDy₈Ni₆Co₂ glasses prepared by melt spinning after different pre-aging regimes was investigated. The modelling of the transformation at the glass transition and the crystallisation was tested by a more general Johnson-Mehl-Avrami-Kolmogorov model and by the determination of the local kinetic parameter. The relaxation was tested with an lnt kinetic model after Gibbs.     

Determination of mepiquatchloride in animal and plant matrices by ion chromatography with conductivity detection

Summary A new residue method, based on ion chromatography, for the determination of trace amounts of the ionic plant growth regulator mepiquatchloride is described. The method is adapted to plant and animal matrices and does not require any derivatization steps. This new technique provides higher recoveries of the analyte, better reproducibility and increased speed than the previous method. The limit of determination is 0.05 mg/kg.     

Realisation and metrological characterisation of thickness standards below 100 nm

High-accuracy film thickness measurements in the range below 100 nm can be made by various complex methods like spectral ellipsometry (SE), scanning force microscopy (SFM), grazing incidence X-ray reflectometry (GIXR), or X-ray fluorescence analysis (XRF). The measurement results achieved with these methods are based on different interactions between the film and the probe. A key question in nanotechnology is how to achieve consistent results on a level of uncertainty below one nanometre with different techniques.Two different types of thickness standards are realised. Metal film standards for X-ray techniques in the thickness range 10 to 50 nm are calibrated by GIXR with monochromatised synchrotron radiation of 8048 eV. The results obtained at four different facilities show excellent agreement. SiO₂ on Si standards for SE and SFM in the thickness range 6 to 1000 nm are calibrated by GIXR with monochromatised synchrotron radiation of 1841 eV and with a metrological SFM. Consistent results within the combined uncertainties are obtained with the two methods. Surfaces and interfaces of both types of standards are additionally investigated by transmission electron microscopy (TEM). PACS 61.10.Kw; 68.55.Jk; 06.20.Fn; 06.60.Mr; 07.79.Lh     

First synthesis of magnesacyclopentadienes from acetylenes by treatment with BuMgHlg in the presence of Zr complexes

Treatment of internal acetylenes and allenes with BuMgHlg (Hlg = Cl, Br) in the presence of Cp₂ZrCl₂ selectively leads to the formation of substituted magnesacyclopenta-2,4-dienes and alkylidenemagnesacyclopentenes.     

Roughness reduction in submicron waveguides by low-molecular weight development

Roughness reduction of a submicron waveguide profile in chemically amplified negative resist is here performed by proper selection of an alkali-based developer, taking into account that its smaller molecules lead to smoother resist surface by altering the developing mechanism of aggregate extraction performed with standard quaternary ammonium hydroxide. Roughness is then analyzed by means of classical Atomic Force Microscope inspection; furthermore, a non-invasive line edge roughness analysis approach based on top-down scanning electron microscope acquisition gives comparable results, in terms of standard deviation and molecular aggregate periodicity.     

Preparation and mechanical properties of layers made of recombinant spider silk proteins and silk from silk worm

Layers of recombinant spider silks and native silks from silk worms were prepared by spin-coating and casting of various solutions. FT-IR spectra were recorded to investigate the influence of the different mechanical stress occurring during the preparation of the silk layers. The solubility of the recombinant spider silk proteins SO1-ELP, C16, AQ24NR3, and of the silk fibroin from Bombyx mori were investigated in hexafluorisopropanol, ionic liquids and concentrated salt solutions. The morphology and thickness of the layers were determined by Atomic Force Microscopy (AFM) or with a profilometer. The mechanical behaviour was investigated by acoustic impedance analysis by using a quartz crystal microbalance (QCMB) as well as by microindentation. The density of silk layers (d<300 nm) was determined based on AFM and QCMB measurements. At silk layers thicker than 300 nm significant changes of the half-band-half width can be correlated with increasing energy dissipation. Microhardness measurements demonstrate that recombinant spider silk and sericine-free Bombyx mori silk layers achieve higher elastic penetration modules E_EP and Martens hardness values H_M than those of polyethylenterephthalate (PET) and polyetherimide (PEI) foils.