In this paper, we present an upwinding methodology for systems of conservation laws. Our aim is to construct upwind schemes which do not require the extraction of the eigensystem of the jacobian matrix (but just the knowledge of the eigenvalues) and rely on the introduction of an appropriate polynomial approximation. @U @t + @F(U) @x = 0; t > 0; x 2 I R ; (1) avec U(x; t) un etat de l'espace de...

In this research, we used the surface acoustic wave (SAW) sensor to detect chemical compounds such as ammonia, methane, and ammonia-methane mixture gases. Very low concentration of ammonia (~250 ppb) and methane (~9 ppm) can be detected by our SAW devices. And we used mesoporous carbon hollow nanosphere in Poly-N-vinylpyrrolidone (PNVP) film to increase the sensitivity to ammonia from 6.91 to 1...

The double alkylation of N-vinylpyrrolidone (N-VP) with 1,8-dibromooctane yields paraffin-like oligomeric chains bearing polymerizable vinyl moieties. These oligomers were radically crosslinked in bulk with N-VP as co-monomer yielding swellable polymer disks. The vinylic side groups of the N-VP oligomers allow thiol-ene click reactions with 2-aminoethanethiol hydrochloride to obtain reactive am...

Cu particles with different architectures such as pyramid, cube, and multipod have been successfully fabricated on the surface of Au films, which is the polycrystalline Au substrate with (111) domains, using the electrodeposition technique in the presence of the surface-capping reagents of dodecylbenzene sulfonic acid and poly(vinylpyrrolidone). Further, the growth evolution of pyramidal Cu nan...