Forschungs- und Entwicklungszentrum Fachhochschule Kiel (Germany)

Abstract Using an additively manufactured demonstrator, this article discusses the influence of production-related challenges of laser powder deposition melting on the manufacturing costs of the component. In particular, the effort required to determine a suitable manufacturing strategy must be considered in the cost calculation, as this accounts for a substantial proportion of the manufacturing costs. Neglecting this effort in the calculation can lead to considerable economic loss.

Abstract Enhancements on power electronic systems with reduced chip area and miniaturized passive components are subject of several research activities in academics and industry. To realize such future electronic devices, it is necessary to incorporate wide bandgap semiconductor technology such as silicon carbide and gallium nitride operating at higher temperatures. Therefore, the development of novel materials with high thermal conductivities and stability, withstanding harsh environments up to 300°C is of major interest. Especially, polymeric encapsulation materials have to be improved because of common degradation effects above 175°C. Ceramic (nonpolymeric) materials with thermal conductivities above 5 W/(m·K) already illustrated promising results for the encapsulation of power electronics. The present work illustrates recent developments and improvements on novel ceramic encapsulation materials, which finally avoid critical interactions with the chip surface. Furthermore, advances in reliability will be discussed in terms of passed high-temperature reverse bias and humidity tests correlated with relevant material properties.

Abstract Enhancements on power electronic systems with reduced chip area and miniaturized passive components are subject of several research activities in academics and industry. To realize such future electronic devices, it is necessary to incorporate wide bandgap semiconductor technology such as silicon carbide and gallium nitride operating at higher temperatures. Therefore, the development of novel materials with high thermal conductivities and stability, withstanding harsh environments up to 300°C is of major interest. Especially, polymeric encapsulation materials have to be improved because of common degradation effects above 175°C. Ceramic (nonpolymeric) materials with thermal conductivities above 5 W/(m·K) already illustrated promising results for the encapsulation of power electronics. The present work illustrates recent developments and improvements on novel ceramic encapsulation materials, which finally avoid critical interactions with the chip surface. Furthermore, advances in reliability will be discussed in terms of passed high-temperature reverse bias and humidity tests correlated with relevant material properties.

Der folgende Beitrag handelt von der Versorgungslandschaft im Bereich der Altenpflege. Im Mittelpunkt stehen Fragen der Methoden, Zustandigkeiten beziehungsweise der Reichweite von Planungen, die sicherstellen, dass Leistungen fur altere Menschen tatsachlich im Sinne der Nutzerinnen und Nutzer gestaltet werden.

The radar signatures of Kelvin arms of the wave pattern generated by a moving ship are studied by using an improved composite surface model for the calculation of the radar backscatter from the ocean surface. The modulation of the normalized radar backscattering cross section (NRCS) by the cusp waves forming the Kelvin arms is calculated as function of the ship heading relative to the radar look direction for different radar frequencies and polarizations. According to the model, the modulation depth of the NRCS increases with radar frequency and is larger at HH than at VV polarization. One example of an ocean scene with a moving ship is presented which was imaged by the 3-frequency/multipolarization SAR aboard the Space Shuttle Endeavour during the SLR-C/X-SAR mission. It is shown that the measured modulation depths agree quite well with the simulated ones.