Repetitive sub-gigawatt rf source based on gyromagnetic nonlinear transmission line.

We demonstrate a high power repetitive rf source using gyromagnetic nonlinear transmission line to produce rf oscillations. Saturated NiZn ferrites act as active nonlinear medium first sharpening the pumping high voltage nanosecond pulse and then radiating at central frequency of about 1 GHz: shock rise time excites gyromagnetic precession in ferrites forming damping rf oscillations. The optimal length of nonlinear transmission line was found to be of about 1 m.

Influence of changing pulse repetition frequency on chemical and biological effects induced by low-intensity ultrasound in vitro.

This study was undertaken to examine ultrasound (US) mechanisms and their impact on chemical and biological effects in vitro as a function of changing pulse repetition frequency (PRF) from 0.5 to 100Hz using a 1MHz-generator at low-intensities and 50% duty factor (DF). The presence of inertial cavitation was detected by electron paramagnetic resonance (EPR) spin-trapping of hydroxyl radicals resulting from sonolysis of water.