The conductive properties of bulk SrnormalNbxnormalTi1−xnormalO3 (SNT) and porous SrnormalNbxnormalTi1−xnormalO3 –yttria-stabilized zirconia (YSZ) composites for x=0.01 , 0.05, and 0.20 have been examined under relevant solid oxide fuel cell (SOFC) operating temperatures and redox cycling conditions. The porous composite conductivities were approximately 1 order of magnitude lower than the corresponding bulk material. In order to obtain reasonable conductivity levels for SOFCs, samples were prereduced at 1400°C in H2 . The conductivity of prereduced samples increased with increasing Nb content when directly measured in humidified H2 ; however, when considering the conductivities measured after redox cycling, there appears to be no benefit to using higher dopant levels. After redox cycling at 800°C , a composite conductivity of 1S∕cm at 800°C in humidified H2 (3% normalH2O ) was achieved for x=0.01 and 0.05 and a composite conductivity of 0.5S∕cm was achieved for x=0.20 . Fuel cell power densities of 415mW∕cm2 at 700°C and 640mW∕cm2 at 800°C were achieved in humidified H2 (3% normalH2O ) with a porous SNT–YSZ anode infiltrated with 1wt% Pd and 3wt% CenormalO2 , a 50μm thick YSZ electrolyte, and an normalLa0.8normalSr0.2normalFeO3 (LSF), LSF–YSZ cathode. The implications of these results for the development of redox-stable anodes are discussed.

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This case report presents a patient with painful legs and moving toes on the right side followed by the development of involuntary movements in his right hand. The frequencies of the semirhythmic muscle activities in both extremities were different. This finding excludes one central pacemaker for both and supports the notion that separate oscillators in the segmental interneuron pool of different spinal areas may drive the individual movements in this case.

Three-wavelength extinction technique for characterizing aerosols under industrial conditionsA new developed in-situ and on-line measuring device has been adapted to the conditions of industrial gas cleaning equipment in order to realize measurements of particle sizes and concentrations of aerosols. It has been used to characterize hydrochloric acid, sulphuric acid and salt solution droplets. The measuring method is based on the three-wavelength extinction technique. The results, which have been achieved with this method, have been compared with measurements of a particle sampler for silizium dust and oil droplets and with chemical analysis for acid aerosols. There has been good agreement between the different measuring techniques. The method has successfully been tested in particular for liquid aerosols with high particle concentrations up to 10 9 particles/ cm 3 .

Wanderungen metallgebundener Silylgruppen an einen Liganden sind in der Chemie von obergangsmetall-SilylKomplexen nicht allzu haufig. Ein interessantes Beispiel fur eine derartige Umlagerung wird beobachtet, wenn EisenSilyl-Komplexe des Typs C P ( C O )~F~ -SiR3 (Cp = q5-C5H5) rnit starken Basen behandelt werden. Nach Untersuchungen mehrerer Gruppen 2-4) erfolgt dabei zunachst Deprotonierung des Cyclopentadienyl-Liganden, gefolgt von einer intramolekularen Wanderung der Silylgruppe vom Eisenatom zum Cp-Ring [GI. (l)Es lag zunachst nahe anzunehmen, daD 2 ebenfalls durch baseinduzierte Umlagerung analog GI. (1) gebildet wird. Wir berichten in dieser Arbeit iiber erganzende Versuche zu Teilschritten der Reaktion, die beweisen, daD dies nicht der Fall ist. ErgebnisseDie Umsetzung von Cp2WX2 (X = C1, Br, I) rnit Li[Si-(SiMe3)J . 3 THF (1)6) in unpolaren Losungsmitteln lauft unabhangig von der Art des Halogenliganden im eingesetzten Wolframocendihalogenid selbst unter Kiihlung der Reaktionslosung so schnell ab, daD keine Zwischenstufen beobachtbar sind. Im Unterschied zur Reaktion von Cp2HfC12 rnit 1, bei der ausschlieDlich CpzHf(C1)Si(SiMe3)3 gebildet wird'), entsteht bei der Umsetzung von Cp2WX2 das Wolframocen-Hydrid-Derivat 2 als einziges beobachtbares und isolierbares metallhaltiges Produkt [GI. (2)]. Seine Ausbeuten sind allerdings sehr stark von X abhangig: sie sinken von X = C1 (56%) iiber X = Br (12%) nach X = I (1%) sehr stark ab. Da 1 auch reduzierend wirkt'), kann dieser Befund rnit den unterschiedlichen Redoxpotentialen der eingesetzten Wolframocendihalogenide im Zusammenhang stehen.