Nanoparticles are coated in-flight with a plasma-enhanced chemical vapor deposition (PECVD) process at ambient or elevated temperatures (up to 300 °C). Two silicon precursors, tetraethyl orthosilicate (TEOS) and hexamethyldisiloxane (HMDSO), are used to produce inorganic silica or silica-organic shells on Pt, Au and TiO2 particles. The morphology of the coated particles is examined with transmission electron microscopy (TEM) and the chemical composition is studied with Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). It is found that both the precursor and certain core materials have an influence on the coating composition, while other parameters, such as the precursor concentration, aerosol residence time and temperature, influence the morphology, but hardly the chemical composition. The coated particles are used to demonstrate simple applications, such as the modification of the surface wettability of powders and the improvement or hampering of the photocatalytic activity of titania particles.

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A new nuclide 'Ha was produced in the bombardment of a Bk target with 93-MeV "0 ions. It was detected via spontaneous fission counting and was shown to have a half-life of about 0.5 min. This activity was also separated from the reaction products by automated rapid chemical separations using cation-exchange chromatography in 0.05M a-hydroxyisobutyric acid. After chemical separation, ' 'Ha was found to decay by spontaneous fission (57+i'd%) and by a emission (E =8.35 MeV, 43%) with a half-life of 27+7 s. The spontaneous fission fragment energy spectrum is compatible with an average total kinetic energy of about 200 MeV.PACS number(s): 23.90.+w, 25.70.Jj, 25.85.Ca, 27.90.+b

Trotz seiner großen Verbreitung und seiner enormen Bedeutung für die Trockenklassierung von Feinstpulvern ist der Abweiseradsichter hinsichtlich der Prozesse am Sichtrad in wesentlichen Punkten noch weitgehend unverstanden. Daher wurde in der vorliegenden Arbeit der Sichtkorb eines Abweiseradsichters durch Umbau optisch zugänglich gemacht. Die aufgenommenen Bilder ermöglichen erstmals eine direkte Beobachtung der Gasströmung und der Partikelbewegung zwischen den Sichtradschaufeln. Insbesondere konnte die Bedeutung von Partikel/Partikel-und Partikel/Sichtradschaufel-Stößen gezeigt werden.In spite of its great importance for the dry classification of fine powders, the processes in deflector wheel classifiers are to a large extent unknown. Therefore, in the present work a commercial available classifier was modified to gain an optical access to the deflector wheel. For the first time, the obtained photographs enable an observation of the gas flow and the particle motion between the blades of the deflector wheel. Especially the importance of particle-particle-and particleblade-collisions could be shown.

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