Synthesis and analytical properties of di(2-pyridyl)-N,N-di[(8-quinolyl)amino]methane

The synthesis and preliminary analytical assessment of di(2-pyridyl)-N,N-di[(8-quinolyl)-amino]methane is reported. It shows some potential as a reagent for iron(II).     

Die Vanadin-Koordination in den Phasen 4 PbO · V2O5 und 8 PbO · V2O5

Coordination of Vanadium in the Phases 4 PbO · V₂O₅ and 8 PbO · V₂O₅ It is demonstrated, using infrared spectroscopy, that the coordination of vanadium in the two binary phases 4 PbO · V₂O₅ and 8 PbO · V₂O₅ is tetrahedral. The spectra in the V? O stretching region closely resembles that of the lead(II) orthovanadate, Pb₃(VO₄)₂.     

Seamless MESO-NH modeling over very large grids

With the computing power it brings, the new generation of massively parallel computers allows one to perform a “seamless” modeling of weather on large grids, but it requires a large parallel computing capability for the models. Due to improvements in this direction in the meteorological model of the French research community MESO-NH, a computing performance of over 4 Teraflop/s was obtained with 130 000 cores on the machine of the European computer center PRACE. This is a first in France for a weather code. A high resolution simulation, covering the Atlantic and Europe, of the tropical cyclone Helene and its interaction with a planetary wave was also conducted, for which the excellent result gives hope to an improved weather forecasting in Europe.     

Molecular mobility in biodegradable poly( $ varepsilon$ -caprolactone)/poly(hydroxyethyl acrylate) networks

Poly( e varepsilon -caprolactone)/poly(hydroxyethyl acrylate) networks have been investigated by thermally stimulated depolarization currents (TSDC) and differential scanning calorimetry (DSC). The introduction of hydrophilic units (HEA) in the system aiming at tailoring the hydrophilicity of the system results in a series of copolymer networks with microphase separation into hydrophobic/hydrophilic domains. Polycaprolactone (PCL) crystallization is prevented by the topological constraints HEA units imposed in such heterogeneous domains. Moreover, the mobility of the amorphous PCL chains is enhanced as revealed by the main relaxation process which becomes faster. The glass transition of PHEA-rich domains shifts to lower temperatures, as the total amount of PCL in the copolymer increases, due to the presence of PCL units within the same region. The behaviour of the copolymer networks swollen with different content of water has been investigated to analyze the interaction between water molecules and hydrophobic/hydrophilic domains and provide further insights into the molecular structure of the system.     

Hyperfine interactions in ZrO2–5 wt.% Al2O3 ceramics

Two powder samples of ZrO₂-5 wt.% Al₂O₃ derived from precursor solutions of different pH – 2 for sample (C) and 4 for sample (D) – were prepared by the precipitation method. They were studied using PAC between RT and 1150oC and XRD after heating at increasing temperatures. According to XRD, the addition of Al₂O₃ causes the complete stabilization of tetragonal zirconia in both samples. At a nanoscopic level, however, they present different interactions and thermal evolutions. Sample (C) exhibits predominantly the t₁- and dynamic t₂-forms already reported for pure and yttria-doped stabilized tetragonal zirconias. On the other hand, sample (D) exhibits a novel nanoconfiguration depicted by a totally asymmetric and dynamic EFG whose population achieves 86% at 1150oC and which has been associated to aluminium solubility in zirconia. Upon cooling gradually to RT from the highest temperature, (C) transforms completely to m-ZrO₂ and (D) remains 65% in the metastable tetragonal phase. This revised version was published online in August 2006 with corrections to the Cover Date.     

Extractive scintillators for alpha liquid scintillation counting: Anomalies in quenching evaluation

Two important effects in quenching evaluation when using some commercial extractive scintillators in alpha liquid scintillation counting are described. One affects the system quenching value but not the efficiency, while the other modifies the efficiency with no important change in the quenching. For these cocktails, alternative procedures for efficiency evaluation must be chosen. We propose an inner standard procedure which gave adequate results in the application to different kinds of samples.