Solid-state phase equilibria in the V2O5−Fe8V10W16O85 system

Phase equilibria being established in the solid state in the system V₂O₅?Fe₈V₁₀W₁₆O₈₅ were examined by X-ray phase powder diffraction and DTA. It has been found that the system of interest is a real two-component system with an eutectic temperature 620±5°C.     

Identification of "insoluble" red dyewoods by high performance liquid chromatography-photodiode array detection (HPLC-PDA) fingerprinting

The paper describes a high performance liquid chromatography-UV/Vis spectrometry detection analytical approach to the identification of some redwood species of historical importance in textile dyeing. The group of extracted dyestuffs considered as "insoluble" because of their non-aqueous or alkaline extraction conditions is present in the wood of the Pterocarpus family and Baphia nitida species. First, the crude extracts of tinctorial and related species and their chromatographic fingerprints were studied. This part of work shows that some species not yet mentioned in the literature have potential dyeing properties. Subsequent experiments performed on the redwood cargo of a 200-year-old archaeological shipwreck allowed identification of the water-logged wood species. Furthermore, the different methods of dyestuff extraction used for dyeing according to traditional recipes and their impact on analytical results were studied. They show that standard recovery obtained by acid hydrolysis of dyestuff from dyed yarns is inadequate. Hence, alternative solvent-based procedures were proposed. The identification of species in textile threads then becomes possible. The applied approach was validated by analysis of dyed reference yarns with some indications of crude material extraction mode. The employed method of analysis seems to be useful for "insoluble" wood species identification in cultural heritage artifacts as well as for phytochemical purposes, despite the fact that very few detected color compounds were chemically identified.     

On the Sharpness of Mockenhaupt’s Restriction Theorem

We prove that the range of exponents in Mockenhaupt’s restriction theorem for Salem sets (Geom Funct Anal 10:1579–1587, 2000), with the endpoint estimate due to Bak and Seeger (Math Res Lett 18:767–781, 2011), is optimal.     

Inkjet-printed thiol self-assembled monolayer structures on gold: quality control and microarray electrode fabrication

Laterally structured, self-assembled monolayers (SAMs) of different thiols (HS-R-X, R = (CH 2) 3-16, X = -CH 3, -COOH, -NH 2) on gold have been prepared by inkjet printing. The printer is a modified, low-cost desktop printer (Epson Stylus Photo R200), the ink is a 1 mM solution of the thiol in ethanol/glycerol (6:1). The quality of inkjet-printed large area SAMs obtained in this study is between that of a layer self-assembled from a thiol solution and that obtained by soft lithography, according to cyclic voltammetry, electrochemical impedance spectroscopy, scanning electrochemical microscopy (SECM), and polarization-modulated Fourier transform infrared reflection-absorption spectroscopy (PM IRRAS). For the first time, simultaneous printing of two different thiols in a single print job as an alternative to sequential printing and backfilling is demonstrated. The smallest structures consisting of conductive disks of 40 microm diameter were analyzed as single spots by SECM and as random array electrodes with different average disk-disk distance. Conductive band electrodes with variable bandwidth (300 microm to 1 cm) are presented, as well as a pH switchable band structure. As compared to stamping, inkjet printing allows for simultaneous multiple thiol printing in a single print job with the resolution limited only by the droplet size and the precision of the translation stage.