"A Pocket Sized Monitor of Dangerous Microwave Power Levels"
A miniature battery-operated microwave power monitor is described which operates across the threshold range of biologically dangerous power levels with approximately frequency-independent characteristics up to about 100GHz. CMOS circuitry causes an alarm signal to occur, or enables one to integrate the total microwave energy received over a given period on the basis of a thermal change of resistance in a thin Ge film due to microwave absorption.
Structure change and resistivity step of evaporated Ge films in dependence on the substrate temperature
Results are reported of an investigation of the electrical properties of Ge films evaporated on Duran glass at different substrate temperatures TS. The resistivity measurements allow to distinguish between amorphous and polycrystalline films on account of a steep resistivity step of four or seven orders of magnitude at 294 or 80 K lattice temperature, respectively as found at TST = 135°C. This step is due to the fact that with the relatively high evaporation rate used, grains of only equal size are performed, and that with decreasing TS at TST all grains fall below a critical grain size. By the analysis of the lattice temperature dependence of the resistivity of the polycrystalline films, making use of the mean free path of carriers between two collisions at grain boundaries, the critical grain size was found to be about an elementary cell. 
 
 
 
Es wird uber ergebnisse einer Untersuchung der elektrischen Eigenschaften von Ge-Filmen berichtet, die bei verschiedenen Substrattemperaturen TS auf Duranglas aufgedampft wurden. Mit den Widerstandsmessungen kann zwischen amorphen und polykristallinen Schichten unterschieden werden, weil bei TST = 135°C ein steiler Sprung des spezifischen Widerstandes um vier bzw. sieben Zehnerpotenzen bei 294 bzw. 80 K Gittertemperatur auftritt. Dieser Sprung ist dadurch bedingt, das bei der verwendeten relativ hohen Aufdampfrate nur Korner gleicher Grose entstehen und mit abnehmendem TS bei TST alle Korner eine kritische Korngrose unterschreiten. Durch die Analyse der Gittertemperaturabhangigkeit des spezifischen Widerstandes der polykristallinen Schichten wird anhand der mittleren freien Weglange der Ladungstrager zwischen zwei Stosen an Korngrenzen gefunden, das diese kritische Korngrose etwa die der Elementarzelle ist.
Investigation of scatter radiation of non-circular X-ray scan trajectories
Modern interventional X-ray devices are highly maneuverable and allow complex 3D imaging trajectories. New scan trajectories enable not only optimized object sampling but also introduce new approaches for dynamic 3D imaging. In this paper, we investigated the scatter radiation of two different scan trajectories. The scatter radiation was sampled by a rail setup with dosimeters at defined positions. After data analysis, contour maps were generated which show for four exemplary heights the scatter radiation distribution. The alternative scan trajectory showed smaller dose exposures at heights correlated to upper torso and head areas of a model physician. Keywords—Image acquisition, alternative scan trajectory, circular tomosynthesis, scatter radiation distribution