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An accurate and flexible large-signal model based on an analysis of the characteristics of InP heterojunction bipolar transistors (HBT) is implemented as a seven-port symbolically defined device (SDD) in Keysight ADS. The model is based on an improved Keysight HBT model formulation, avoiding an erroneous RCICBC transit time contribution from the intrinsic collector region. The model has been verified by comparing simulated and measured DC and small-signal S-parameters at multiple bias points for a 1 x 15 µm² emitter InP HBT. [ABSTRACT FROM AUTHOR]

The article report the investigation of gamma irradiation effects on the collector-emitter saturation voltage of InGaP/GaAs heterojunction bipolar transistors and it is found that the saturation voltage increases to exposure the gamma irradiation with a total dose of 10 Mrad(Si) and subsequent annealing at room temperature. Topics include the analysis shows the increase of saturation voltage is mainly caused by irradiation-induced defects in the base-collector space charge region.

The article discusses the market status and the problem faced by carbon black industry in 2006-2007. It provides an overview of several developments in the sector with corresponding statistical records including the growth of export market with 21.5% increase in 2007. It cites the challenges faced by the sector including low operating rate and environmental issues. It also provides several suggestions to address such issues in the industry including the understanding of macro economic trends.