Ion transfer processes at ionic liquid based redox active drop deposited on an electrode surface

Ion transfer across the boundary formed at an ionic liquid drop deposited on an electrode immersed in aqueous solution, generated by electrochemical redox reaction at the electrode-ionic liquid interface, is studied to obtain information about the ability of anions to be transferred into a room temperature ionic liquid.     

Nanostructuration of soft hydrogels: synthesis and characterization of saccharidic methacrylate gels

With the tremendous development of biosensors, there is a strong need in new biocompatible materials avoiding possible denaturing of biological species, which can be easily processed with already existing technologies. The scope of this study was to develop new hydrogels which could be nanostructured by common lithographic methods. Therefore, new methacrylate hydrogels are described, which include functionalized monomers bearing either neutral groups, such as saccharidic moieties, anionic, or cationic groups. The gels have been synthesized by redox or photochemical-initiated radical polymerization. Their porosity has been characterized by thermoporometry, AFM, and electronic microscopy. The kinetics of the photocross-linking has been analyzed by piezorheometry on some of the materials and has been shown to be compatible with technological process time range. Although the obtained hydrogels are soft, their nanostructuration into 500-nm patterns could be performed by nanoimprint photolithography process, and these patterns were observed to be stable for several months.     

Transformation of n- hexane on PtAl/MCM-41 and PtAl/SBA-15

PtAl/MCM-41 and PtAl/SBA-15 materials were prepared by post-synthesis alumination followed by introduction of platinum by ion exchange. The samples were characterized by pyridine adsorption followed by FTIR and TPR of hydrogen. The catalytic behavior was explored in the transformation of n-hexane. This revised version was published online in August 2006 with corrections to the Cover Date.     

Laser-polarized Xe NMR and MRI at Ultralow Magnetic Fields

Laser-polarized ¹²⁹Xe and a high-T_csuperconducting quantum interference device (SQUID) are used to obtain magnetic resonance images in porous materials at a magnetic field of 2.3 mT, corresponding to a Larmor frequency of 27 kHz. Image resolution of 1 mm is obtained with gradients of only 1 mT/m. The resolution of xenon chemical shifts in different physicochemical environments at ultralow fields is also demonstrated. Details of the circulating flow optical pumping apparatus and the SQUID spectrometer are presented.     

Confinement of THz surface waves on the subwavelength size metal waveguide

We investigate surface plasmon waves propagating on planar Goubau lines, so-called Goubau modes, using a guided-wave terahertz spectroscopy system based on a freely positionable electrooptic probe. We show the radial nature of the Goubau mode and its confinement around the Goubau line over a few tenths of microns (??/10).     

Minkowski operations and vector spaces

Mathematical morphology started as a set of tools for analysing images by the use of transformations based on set-theoretical operations which are the Minkowski sum and subtraction. It was first developed for the analysis of binary images. Its extension to grey-level images was a later development with the extension of the Minkowski operations to real-valued functions in terms of sup-convolution and inf-convolution. The purpose of this paper is to define a type of convolution between set-valued maps, to study its properties, and to establish some associated differential relations. This set-convolution map allows us to extend the Minkowski sum and substraction to multivalued functions and to functions with vectorial values.     

Searching for the dopant ion in Eu-activated BaMgAl10O17 phosphor with synchrotron diffraction

Searching for the multiple sites predicted in the literature for the europium activator in the BaMgAl₁₀O₁₇:Eu²⁺ phosphor, we undertook a detailed structural study using synchrotron powder diffraction. Three different positions were found for Eu²⁺ in the Beevers-Ross site, near the mid-oxygen position and in substitution for the interblocks Al-O-Al bridge. By favoring the migration of the activator ion, the resulting vacancies in the Beevers-Ross sites may be a major cause of the degradation of the phosphor.