2008 NOV 17 - (VerticalNews.com) -- "Mathematical simulation on the rise and decay kinetics of transient electroluminescence (EL) in organic light emitting diodes (OLEDs) is presented. The transient EL is studied with respect to a step voltage pulse," scientists writing in the Journal of Physics D - Applied Physics report.

  "While rising, for lower values of time, the EL intensity shows a quadratic dependence on (t - t(del)), where t(del) is the time delay observed in the onset of EL, and finally attains saturation at a sufficiently large time. When the applied voltage is switched off, the initial EL decay shows an exponential dependence on (t - t(dec)), where t(dec) is the time when the voltage is switched off. The simulated results are compared with the transient EL performance of a bilayer OLED based on small molecular bis(2-methyl 8-hydroxyquinoline)(triphenyl siloxy) aluminium (SAIq). Transient EL studies have been carried out at different voltage pulse amplitudes. The simulated results show good agreement with experimental data," wrote M. Shukla and colleagues ...read more

  2008 NOV 17 - (VerticalNews.com) -- "We report a method to synthesize amorphous hollow carbon spheres, with diameters ranging from 100 to 800 nm, which are dispersed among bent graphitized carbon nanotubes using radio frequency plasma-enhanced chemical vapour deposition in mixed CH4/H-2 gases," scientists in Changchun, People's Republic of China report.

  "The products are characterized by techniques including scanning electron microscopy, energy-dispersive x-ray spectroscopy, Raman spectroscopy and transmission electron microscopy. It is found that MgO and Ni nanoparticles together with hydrogen play important roles in the formation of the spheres," wrote G.M. Yang and colleagues, Jilin University ...read more

  2008 NOV 17 - (VerticalNews.com) -- According to a study from Russia, "The general features and peculiarities of the stationary electrode microwave discharge (EMD) are presented. EMD is ignited near the tip of the powered electrode (antenna) and its luminous plasma region is less than the dimensions of the discharge chamber."

  "The possible areas of EMD application are demonstrated. Results of spatially resolved optical emission spectroscopy of nitrogen EMD are presented. The joint experimental-simulation method is used to process the 2(+) nitrogen band emission for measurements of electron density and electric field strength near the electrode plasma sheath of the nitrogen discharge," wrote Y.A. Lebedev and colleagues ...read more