Rain Attenuation at Millimeter and Submillimeter Wavelengths

The rain attenuation was calculated by using the Marshall-Palmer, Best, Joss-Thomas-Waldvogel and Weibull distributions for raindrop-size. The results were compared with the recent measurements from 8 to 312.5 GHz at the rain rate R = 50mm/hr. Especially, the Weibull distribution has a good agreement with the measurements at 312.5 GHz (0.96 mm) in the submillimeter wavelength. Specific attenuation values from 1 to 1000 GHz were calculated for a rain temperature of –10°C, 0°C and 20°C by using the Weibull distribution.     

Dielectric investigations of associate formation process in thin nitrobenzene interlayers formed between metal substrates

Studies of thickness and temperature dependencies of the dielectric susceptibility of nitrobenzene interlayers formed on conductive substrates were carried out. The obtained data were processed under the assumption of the existence of dimers (with opposite directions of molecular dipole moments) in orientationally ordered wall-adjacent layers. The results were treated on the basis of Lifshits theory.     

Papieruntersuchung

Analytical and Bioanalytical Chemistry -     

Photoluminescence linewidth broadening due to alloy/thickness fluctuation of CdxZn1 − xSe/ZnSe triple quantum wells

Photoluminescence (PL) linewidth broadening of Cd_xZn_{1 − x}Se/ZnSe triple quantum wells, grown on GaAs substrates by molecular beam epitaxy (MBE), has been investigated. Various quantum well (QW) samples have been prepared with different QW thickness and composition (Cd-composition). Measured and calculated PL linewidth are compared. Both composition and thickness fluctuations are considered for the calculation with the parameters such as the volume of exciton, nominal thickness and composition of QWs. Surface roughness measured by atomic force microscopy (AFM) is used to estimate the interface roughness. Results show that when Cd-composition increases additional linewidth broadening due to Zn/Cd interdiffusion is enhanced.