Some aspects of metal-catalyzed heterogeneous enantioselective reactions are reviewed with specific reference to four different systems where the phenomena that control enantioselection appear to be very different. In the case of glucose electro-oxidation, it is clear that any intrinsic chirality present at the metal surface plays a vital role. With α-keto hydrogenation, achiral surfaces modified…
Solid solutions of TiB2-ZrB2 and TiB 2-HfB2 were obtained under an inert atmosphere by high-energy ball-milling mixtures of Ti/Zr/B and Ti/Hf/B, respectively. Milling promoted mechanically induced self-sustaining reactions (MSR), and the ignition time was dependent on the initial composition of the mixture. The stoichiometry of Ti1-xZrxB2 and Ti1-xHf xB2 solid solutions was controlled by adjusting…
This paper examines the structural changes with temperature and composition in the Yb2Si2O7–Y2Si2O7 system; members of this system are expected to form in the intergranular region of Si3N4 and SiC structural ceramics when sintered with the aid of Yb2O3 and Y2O3 mixtures. A set of different compositions have been synthesised using the sol–gel method to…
The local structure of TiBC and amorphous carbon (a-C) nanocomposite films (TiBC/a-C) was correlated with their optical and electrical properties. TiBC/a-C films with increasing C content were deposited by magnetron co-sputtering from TiC:TiB2 (60:40) and graphite targets. Chemical composition is determined by electron energy-loss spectroscopy. Grazing incidence X-ray diffraction reveals that the microstructure of the…
A synthetic route to attain photonic multilayers that presents controlled porosity only at the middle-layer level is shown. The spectral resonance associated with this porous layer shows strong sensitivity to the presence of vapors adsorbed or condensed within the void network, providing a potentially relevant material for gas detection. The importance of the interplay between…
Thin (40 nm and 160 nm) CrN coatings were deposited on steel by reactive magnetron sputtering deposition, varying the N2 flow. The coatings were characterized in the as-deposited condition and after annealing in air at 500 °C for 1 h, by X-Ray Diffraction, Transmission Electron Microscopy, Raman and Fourier Transform Infrared spectroscopies. Hardness was measured…
This paper presents the main conclusions of our study of the Arabic documents preserved in the Archivo Histórico Provincial of Granada. The analysis of the contents of each document, the materials and inks used in their support, and also the similarities of the page layout reveals the use of identical production protocols. Furthermore, this research…
Orthopaedic materials may improve its capacity to resist bacterial adherence, and subsequent infection. Our aim was to test the bacterial adherence to alpha-tocopherol (frequently named vitamin E, VE) doped or blended UHMWPE with S. aureus and S. epidermidis, compared to virgin material. Collection strains and clinical strains isolated from patients with orthopaedic infections were used,…
The microstructure and chemical bonding of DLC films prepared by plasma assisted chemical vapor deposition on acrylic rubber (ACM) are studied in this paper. The temperature variation produced by the ion impingement during plasma cleaning and subsequent film deposition was used to modify the film microstructure by controlling the different degrees of strain applied to…
