Fixed point free mappings which satisfy a Darbo type condition

We give constructions of continuous mappings on normed spaces which satisfy a Darbo type condition with respect to a measure of noncompactness and do not have fixed points or even have positive minimal displacement. An estimate for the minimal displacement is given

Influence of high Al fraction on reactive ion etching of AlGaN/GaN heterostructures

In this study, the results of reactive ion etching (RIE) process of diversified Al content AlxGa1–xN/AlN/GaN/sapphire heterostructures were presented. The Al fractions of 22, 25, 31 and 36% were examined. An impact of Al content in the heterostructures on the etch rates and surface morphology was investigated. The influence of used Cl2/BCl3/Ar gas mixture with varying of BCl3 flow on the etch rate of Al0.2Ga0.8N/GaN/sapphire, surface morphology and angle of mesa slope, was discussed