The combination of capacitance- and current-voltage （CV/IV） measurements is used to analyze trap generation in sili- con-nanocrystal memory devices during Fowler-Nordheim （FN） programming/erasing cycling. CV and I...The combination of capacitance- and current-voltage （CV/IV） measurements is used to analyze trap generation in sili- con-nanocrystal memory devices during Fowler-Nordheim （FN） programming/erasing cycling. CV and IV curves are meas- ured after certain P/E cycles. The flatband voltage （Vro） and the threshold voltage （VtQ are extracted from CV curves by solv- ing one-dimensional Schrtidinger and Poisson equations. Both hole and electron trappings are observed in the tunneling SiO2. They show up in the accumulation and the inversion, respectively. By fitting FN tunneling current, the area densities of cy- cling-induced electron traps in the blocking oxide and in the tunneling oxide are finally determined.展开更多
Every compressor works in a limited operational range. Surge as one of the sources of this limitation has been studied for many years. In this research, an isolated blade row of compressor rotor is numerically modeled...Every compressor works in a limited operational range. Surge as one of the sources of this limitation has been studied for many years. In this research, an isolated blade row of compressor rotor is numerically modeled and solved. In order to improve operational limit and postpone the surge occurrence, a stepped blade of RAF6E with higher stall angle of attack is used to investigate the near stall flow behavior. In this study, several location of step on blades are tried and the results are compared with the case with no step on blades. It is shown that, as the step moves toward the leading edge of blades, the effect of delay on surge is reduced and even efficiency is also decreased significantly. By moving the step towards the trailing edge, surge is delayed due to the reattachment of flow after the step. Efficiency is also decreased but not in the order of the previous case.展开更多
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2010CB934200)the National Natural Science Foundation of China (Grant No. 60825403)the Hi-Tech Research and Development Program of China ("863" Program) ( Grant No. 2008AA031403)
文摘The combination of capacitance- and current-voltage （CV/IV） measurements is used to analyze trap generation in sili- con-nanocrystal memory devices during Fowler-Nordheim （FN） programming/erasing cycling. CV and IV curves are meas- ured after certain P/E cycles. The flatband voltage （Vro） and the threshold voltage （VtQ are extracted from CV curves by solv- ing one-dimensional Schrtidinger and Poisson equations. Both hole and electron trappings are observed in the tunneling SiO2. They show up in the accumulation and the inversion, respectively. By fitting FN tunneling current, the area densities of cy- cling-induced electron traps in the blocking oxide and in the tunneling oxide are finally determined.
文摘Every compressor works in a limited operational range. Surge as one of the sources of this limitation has been studied for many years. In this research, an isolated blade row of compressor rotor is numerically modeled and solved. In order to improve operational limit and postpone the surge occurrence, a stepped blade of RAF6E with higher stall angle of attack is used to investigate the near stall flow behavior. In this study, several location of step on blades are tried and the results are compared with the case with no step on blades. It is shown that, as the step moves toward the leading edge of blades, the effect of delay on surge is reduced and even efficiency is also decreased significantly. By moving the step towards the trailing edge, surge is delayed due to the reattachment of flow after the step. Efficiency is also decreased but not in the order of the previous case.
