Superhard Phases of Simple Substances and Binary Compounds of the B-C-N-O System: from Diamond to the Latest Results (a Review)

The basic known and hypothetic one- and two-element phases of the B-C-N-O system (both superhard phases having diamond and boron structures and precursors to synthesize them) are described. The attention has been given to the structure, basic mechanical properties, and methods to identify and characterize the materials. For some phases that have been recently described in the literature the synthesis conditions at high pressures and temperatures are indicated.Comment: Review on superhard B-C-N-O phase

Monte Carlo modelling of the transport phenomena in magnetic islands

A Monte Carlo method has been developed that uses two different coordinate systems to model the transport phenomena in the edge plasma of stellarators taking into account the complex magnetic field topology in the stellarator periphery. A self-consistent two-dimensional model is used to investigate the effect of magnetic islands and injected impurities on the transport in the plasma edge. The profiles of the temperature and densities of the plasma, the impurities and the neutral hydrogen particles are calculated for different values of the anomalous perpendicular diffusion coefficient and the impurity source strength and different injection methods. The results show that the existence of magnetic islands significantly influences the transport in the stellarator periphery, and that the injection of impurities into the magnetic island region leads to effective plasma cooling and lowering of the energy flux to the target. (orig.)15 refs.Available from TIB Hannover: RA 71(8/8) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Impact of the test device on the behavior of the acoustic emission signals: contribution of the numerical modeling to signal processing

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