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Breakdown Threshold (breakdown + threshold)
Selected AbstractsMicrowave Breakdown Field in a Resonant Spherical CavityCONTRIBUTIONS TO PLASMA PHYSICS, Issue 4 2006R. Tomala Abstract In the present work, the microwave breakdown threshold in a gas-filled spherical resonator, is determined for the case when the cavity is excited in its lowest order mode, which implies that the microwave field strength depends on both radius and azimuthal angle. A semi-analytical approximation of the breakdown threshold is found using a direct variational approach. The variational predictions are compared with the results of full numerical calculations and demonstrate very good agreement [source] Anomalous behavior of the second and third harmonics generated by femtosecond Cr:forsterite laser pulses in SiC,polymer nanocomposite materials as functions of the SiC nanopowder contentJOURNAL OF RAMAN SPECTROSCOPY, Issue 12 2003S. O. Konorov Abstract Femtosecond pulses of 1.25 µm Cr:forsterite laser radiation were used to study second- and third-harmonic generation in silicon carbide nanopowders embedded in a poly(methyl methacrylate) (PMMA) film. Harmonic generation processes extend the analytical and sensing abilities of light-scattering techniques, including Raman spectroscopy, offering a convenient and efficient approach to the analysis of nanocomposite materials where nanoparticles tend to agglomerate, masking informative features in Raman spectra. The second- and third-harmonic yields are shown to display an anomalous, counterintuitive behavior as functions of the SiC nanopowder content in a polymer film. Whereas harmonic generation in polymer films with a high content of SiC nanocrystals is quenched by the absorption of agglomerating nanoparticles, the influence of absorption is less detrimental in nanocomposite films with a lower SiC content, leading to the growth of the second- and third-harmonic yields. Nanocomposite films with a lower SiC content are also characterized by a higher breakdown threshold, allowing pump pulses with higher fluences to be applied for more efficient harmonic generation. Copyright © 2003 John Wiley & Sons, Ltd. [source] Field-effect transistors based on AlGaN/GaN/AlGaN double-heterostructures grown by MBEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005S. B. Aleksandrov Abstract The double heterostructure (DHS) high-electron mobility transistor (HEMTs) grown by ammonia molecular beam epitaxy (MBE) is investigated both experimentally and theoretically. The band diagram and the sheet 2D electron concentration are computed, predicting alternating electron and hole slabs to co-exist in the structure. The DC characteristics of the DHS HEMT with the 1 µm gate are measured to asses the device performance. A breakdown threshold up to ,200 V is demonstrated for the source/drain voltage in DC operation. The parameters of the DHS and conventional AlGaN/GaN single-heterostructure HEMTs are compared. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Stimulated Raman scattering in mid IR spectral range 2.31,2.75,3.7 µm in BaWO4 crystal under 1.9 and 1.56 µm pumpingLASER PHYSICS LETTERS, Issue 1 2006T.T. Basiev Abstract Stimulated Raman scattering (SRS) in newly developed BaWO4 crystal was investigated. Under 1.9 µm pumping one Stokes component and under 1.56 µm pumping several (up to four) Stokes components were observed. SRS and laser breakdown thresholds were measured. For the first time 2.75 µm and 3.7 µm radiation was obtained using crystalline Raman shifter. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] | ||||||||||