The interaction of the external donor (propyltrimethoxysilane - PTMS) with titanium-magnesium catalysts (TMCs) containing dibutylphthalate (DBP) as internal donor, which were prepared in different ways, was studied by chemical analysis and infrared diffuse reflectance spectroscopy (DRIFTS). The chemical composition of the catalysts after their interaction with heptane solutions of PTMS, PTMS/Al...

We examine the recent data and analysis of Natta et al. concerning the accretion rate on to young stars as a function of stellar mass, and conclude that the apparently steep dependence of accretion rate on mass is strongly driven by selection/detection thresholds. We argue that a convincing demonstration of a physical relationship between accretion and stellar mass requires further studies whic...

We theoretically explored new two-dimensional materials near the ionic instability (three-dimensional structures are favored), with covalent bonded systems (graphene) sitting at the opposite end of the spectrum. Accordingly, monolayer alkaline earth and transition metal halides, many of their bulk forms being layered structures, were investigated by density functional calculations. We thus pred...

Aluminum, the third most abundant element on the earth’s crust, occurs predominantly in oxidic and silicatic minerals. It was first obtained in a pure elemental form by F. Wöhler in 1827 by the reduction of AlCl3 with elemental potassium. In 1859 W. Hallwachs and S. Schafarik synthesized the first organoaluminum compound Et3Al2I3 from elemental Al and EtI, but it took almost 100 years before K....