Optimization of a binary transcoding single filter used for character recognition

We propose a new type of optical filter for character recognition. We intend to show that a unique optimized filter is suitable for binary transcoding of an alphabetical set. The unique filtering consists of a multiplexing from a superposition of holographic filters. Synthesis can be implemented either by analog holography or by numerical holography. A verification obtained from a limited alphabet is presented.     

Action du N-bromosuccinimide sur les dioxolannes en série bicyclo [2.2.1 ]heptanique. Limitation des transpositions de wagner-meerwein

Vicinal benzoyloxy-trans-bicyclo [2.2.1] heptanic bromhydrins, otherwise difficult to obtain are formed from N-bromosuccinimide and norbornanes bearing a 2-aryl-1,3 dioxolane skeleton. The greater stability of the intermediate dioxolenium ion reduces the tendency towards both Wagner-Meerwein rearrangement and neighbouring group participation by chlorine, processes usually observed when a less stable intermediate is involved. Nevertheless, methoxycarbonyl neighbouring group participation and Wagner Meerwein rearrangment occur in methoxycarbonylbicyclo [2.2.1]heptane and in a bornanic compound respectively.     

Ultrafast laser excitation of CO/Pt(111) probed by sum frequency generation: coverage dependent desorption efficiency

CO photodesorption from Pt(111) induced by femtosecond laser pulses is probed by IR+visible sum frequency generation (SFG). Steady state analysis of SFG spectra at varying CO pressure and laser fluence allows one to measure a approximately 5 orders of magnitude decrease of the photodesorption rate constant when CO coverage decreases from 0.37 to 0.07 monolayer. We ascribe this effect in the framework of the Menzel-Gomer-Redhead mechanism to electron delocalization in the CO layer. The lifetime of electronic excitation decreases when coverage decreases.     

A stable distannirane

The first three-membered ring compound containing two tin and one carbon atoms, 1,1,2,2-tetra(2,4,6-triisopropylphenyl)-3-fluorenylidene-1,2-distannirane, has been synthesized in a two-step procedure from the 9-[bis(2,4,6-triisopropylphenyl)fluorostannyl]chloromethylenefluorene.     

Palladium-catalysed direct arylations of heteroaromatics using more eco-compatible solvents pentan-1-ol or 3-methylbutan-1-ol

The palladium-catalysed direct coupling of aryl halides with heteroaromatics in greener solvents than DMF or DMAc, which are often employed for such couplings, would be a considerable advantage for both industrial application and sustainable development. We observed that a range of aryl bromides undergoe coupling via C-H bond activation/functionalisation reaction of thiazoles or imidazoles in moderate to good yields using pentan-1-ol or 3-methylbutan-1-ol as the solvents. Pentan-1-ol and 3-methylbutan-1-ol are less toxic than DMF or DMAc, moreover they are bioresources as they can be obtained by fermentation. Therefore, these reaction conditions are certainly more eco-compatible than those generally employed for such couplings.     

Synthesis,characterization and antibacterial properties of Schiff bases and Schiff base metal complexes derived from 2,3-diamino- pyridine

New copper(II), zinc(II) and nickel(II) Schiff base complexes derived from 2,3-diaminopyridine (DAPY) and selected aldehydes, namely salicylaldehyde (SalH), 4-hydroxybenzaldehyde (4-OHBenz) and 4-nitrobenzaldehyde (4-NO₂Benz), and one mixed Schiff base, DAPY-{4-OHBenz}{SalH} were prepared and characterized by a combination of elemental analyses, i.r. and n.m.r. spectra, and magnetic susceptibility measurements. The Schiff bases and some of the metal complexes display antibacterial properties.