The first self-assembled trimetallic lanthanide helicate: different coordination sites in symmetrical molecular architectures

A tris-tridentate segmental ligand has been designed for the self-assembly of homotrimetallic triple-stranded lanthanide helicates possessing different coordination sites along the threefold axis.     

Equations différentielles invariantes sur les groupes et algèbres de Lie réductifs II

Dans un article précédent, nous avons démontré que si D est un opérateur différentiel bi-invariant sur un groupe réductif G vérifiant la condition de Benabdallah-Rouvière, alors on peut résoudre l’équation différentielle Du=v dans l'espace des distributions G-invariantes (par automorphismes intérieurs) d'ordre fini; nous allons montrer ici que, sous la même hypothèse, on peut résoudre cette équation dans l'espace de toutes les distributions G-invariantes. D'autre part, nous donnons un exemple dans qui montre que les équations différentielles invariantes dans les algèbres de Lie réductives ne sont pas toujours résolubles dans l'espace des fonctions indéfiniment différentiables invariantes.     

A numerical study of non-isothermal turbulent coaxial jets

In this work, we propose to study non isothermal air–air coaxial jets with two different approaches: parabolic and elliptic approaches. The standard k−ε model and the RSM model were applied in this study. The numerical resolution of the equations governing this flow type was carried out for: the parabolic approach, by a “home-made” CFD code based on a finite difference method, and the elliptic approach by an industrial code (FLUENT) based on a finite volume method. In forced convection mode (Fr = ∞), the two turbulence models are valid for the prediction of the mean flow. But for turbulent sizes, k−ε model gives results closer to those achieved in experiments compared to RSM Model. Concerning the limit of validity of the parabolic and elliptic approaches, we showed that for velocities ratio r lower than 1, the results of the two approaches were satisfactory. On the other hand, for r > 1, the difference between the results became increasingly significant. In mixed convection mode (Fr ≅ 20), the results obtained by the two turbulence models for the mean axial velocity were very different even in the plume region. For the temperature and the turbulent sizes the two models give satisfactory results which agree well with the correlations suggested by the experimenters for X ≥ 20. Thus, the second order model with σ _t = 0.85 is more effective for a coaxial jet study in a mixed convection mode.     

Properties of silver nanoparticle-polypyrrole composite film grown on cellulosic paper

Cellulose - In this work, a cellulosic paper substrate (Pap) coated by in situ polymerization of polypyrrole (PPY) was designed. This paper was subsequently coated with silver nanoparticles...     

New probing techniques of radiative shocks

Radiative shock waves propagating in xenon at a low pressure have been produced using 60 joules of iodine laser (λ = 1.315 μm) at PALS center. The shocks have been probed by XUV imaging using a Zn X-raylaser (λ = 21 nm) generated with a 20-ns delay after the shock creating pulse. Auxiliary high-speed silicon diodes allowed performing space- and time-resolved measurement of plasma self-emission in the visible and XUV. The results show the generation of a shock wave propagating at 60 km/s preceded by a radiative precursor. This demonstrates the feasibility of radiative shock generation using high power infrared lasers and the use of XRL backlighting as a suitable diagnostic for shock imaging.     

An Introduction to Entropically-driven Ring-opening Polymerizations

Summary: This mini-review outlines the principles of entropically-driven ring-opening polymerizations (ED-ROPs), a relatively new approach to the synthesis of condensation polymers. The various features of ED-ROPs are noted and examples of applications to polymer synthesis, polymer processing and polymer recycling are discussed.