Nonlinear dynamics in Gunn devices that can exhibit chaotic behaviour is discussed. Evidence for such behaviour is given by laboratory experiments, by computer simulations, and, where available, by simple mathematical reasoning.

It seems to be an open question whether Propositional Dynamic Logic (PDL) has Craig Interpolation. In fact, it even seems to be an open question if this is an open question: Multiple proofs have been claimed to be found but all of them also have been claimed to be wrong, both more or less publicly. This report tries to clarify the situation by discussing the proof by Daniel Leivant [11] from 19...

n the second century of this era, a consul of Rome ntroduced his doctor, Claudius Galenus of Pergamum, to mperor Marcus Aurelius. They got along famously, and alen became the court physician. Renowned for his public ivisections, which allowed startling advances in the fields of natomy and physiology, Galen joined a band of both otable and notorious doctors on a 4,000-year-old quest for he unive...

The study of the radiation hardness subterahertz source from a Gunn diode oscillator and multiplier, based on semiconductor superlattice GaAs/AlAs was continued. dependences output power frequency before after neutron irradiation are experimentally measured. dependence to with fluences 3.5·10 12 , 2.85·10 13 10 14 cm -2 has been analytically estimated. Keywords: Radiation hardness, superlattice...