Entwicklung einer Röntgenzoomlinse

Abbildende Verfahren wie die Röntgenmikroskopie werden in der zerstörungsfreien Werkstoffanalyse eingesetzt, um Auflösungen im Submikrometerbereich zu erreichen. Dort werden abbildende Optiken benötigt, wofür Röntgenlinsen für Photonenenergien oberhalb von 10 keV besonders gut geeignet sind. Damit solche Linsen universell mit konstanten optischen Eigenschaften über einen breiten Photonenenergiebereich einsetzbar sind, wurde in dieser Arbeit erstmalig eine Röntgenzoomlinse entwickelt

On wireless channel parameters for key generation in industrial environments

The advent of industry 4.0 with its idea of individualized mass production will significantly increase the demand for more flexibility on the production floor. Wireless communication provides this type of flexibility but puts the automation system at risk as potential attackers now can eavesdrop or even manipulate the messages exchanged even without getting access to the premises of the victim. Cryptographic means can prevent such attacks if applied properly. One of their core components is the distribution of keys. The generation of keys from channel parameters seems to be a promising approach in comparison to classical approaches based on public key cryptography as it avoids computing intense operations for exchanging keys. In this paper we investigated key generation approaches using channel parameters recorded in a real industrial environment. Our key results are that the key generation may take unpredictable long and that the resulting keys are of low quality with respect to the test for randomness we applied

Effects of thoracic epidural anaesthesia (TEA)on hepatosplanchnic perfusion using TEA as a single procedure and in combination with general anaesthesia

Ziel der vorliegenden prospektiv randomisierten doppelblinden Studie war es, die Auswirkungen einer thorakalen Epiduralanästhesie (TEA) auf die Hepatosplanchnikusperfusion zu untersuchen und die Frage zu beantworten, welchen Einfluss eine zusätzliche Allgemeinanästhesie auf die regionale Hämodynamik in diesem Bereich hat, verglichen mit der einer balancierten Allgemeinanästhesie ohne TEA. Die Beurteilung der Hepatosplanchnikusperfusion erfolgte mit der Indocyaningrün- Plasmaverschwinderate (PDR-ICG) mittels nichtinvasiver Puls-Densitometrie.This randomized controlled double-blind trial was conducted to examine the effects of thoracic epidural anaesthesia (TEA) on hepatosplanchnic perfusion. We investigated the hemodynamics effects on the splanchnic area using TEA as a single procedure and in combination with general anaesthesia. Furthermore we compared our results with the influence of balanced anaesthesia without TEA on gastrointestinal blood flow. Hepatosplanchnic perfusion was estimated noninvasively with the plasma disappearance rate of indocyanine green (ICG- PDR) by pulse dye densitometry