Blue InGaN light-emitting diodes （LEDs） with a conventional electron blocking layer （EBL）, a common n-A1GaN hole blocking layer （HBL）, and an n-A1GaN HBL with gradual A1 composition are investigated numerically,...Blue InGaN light-emitting diodes （LEDs） with a conventional electron blocking layer （EBL）, a common n-A1GaN hole blocking layer （HBL）, and an n-A1GaN HBL with gradual A1 composition are investigated numerically, which involves analyses of the carrier concentration in the active region, energy band diagram, electrostatic field, and internal quantum efficiency （IQE）. The results indicate that LEDs with an n-AIGaN HBL with gradual AI composition exhibit better hole injection efficiency, lower electron leakage, and a smaller electrostatic field in the active region than LEDs with a conven tional p-A1GaN EBL or a common n-A1GaN HBL. Meanwhile, the efficiency droop is alleviated when an n-A1GaN HBL with gradual A1 composition is used.展开更多
The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances ...The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency（IQE）. The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells（QWs） enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.展开更多
Alterations of membrane lipid biophysical properties of sensitiveA549 and resistant A549/DDP cells to the Cis-dichlorodiammine platinum (Cisplatin) were performed by measurements of fluorescence and flow cytometry app...Alterations of membrane lipid biophysical properties of sensitiveA549 and resistant A549/DDP cells to the Cis-dichlorodiammine platinum (Cisplatin) were performed by measurements of fluorescence and flow cytometry approaches using fluorescence dyes of DPH, N-AS and Merocyanine 540 (MC 540) respectively. Fatty acids of membrane lipid of the two cell lines were analyzed by gas chromatography. The results indicated clearly that fluorescence polarization (P) of the DPH probe is 0.169 for the sensitive A549 cell and 0.194 for the resistant A549/DDP cells. Statistical analysis showed significant difference between the two cell lines. The polarizations of 2-AS and 7-AS which reflect the fluidity of surface and middle of lipid bilayer are 0.134 and 0.144 for the sensitive A549 cells as well as 0.171 and 0.178 for the resistant A549/DDP cells respectively, but there is no significant difference of the polarization of 12-AS between the two cell lines. This shows that altera-tions of the membrane fluidity of both cells were mainly located on the surface and middle of the lipid bilayer. In addition, the packing density of phospholipid molecules in the membrane of the two cell lines detected by MC540 probe indicated that lipid packing of A549 cell membranes was looser than that of the A549/DDP cells. And unsaturation degree of plasma membrane fatty acids of the A549/DDP cells was also lower than that of A549 cells. Taken together, it was proposed that the al-teration of membrane lipid biophysical state may be involved in the resistance of A549/DDP cells to cisplatin.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61176043)the Special Funds for Provincial Strategic and Emerging Industries Projects of Guangdong Province,China(Grant Nos.2010A081002005,2011A081301003,and 2012A080304016)the Youth Foundation of South China Normal University(Grant No.2012KJ018)
文摘Blue InGaN light-emitting diodes （LEDs） with a conventional electron blocking layer （EBL）, a common n-A1GaN hole blocking layer （HBL）, and an n-A1GaN HBL with gradual A1 composition are investigated numerically, which involves analyses of the carrier concentration in the active region, energy band diagram, electrostatic field, and internal quantum efficiency （IQE）. The results indicate that LEDs with an n-AIGaN HBL with gradual AI composition exhibit better hole injection efficiency, lower electron leakage, and a smaller electrostatic field in the active region than LEDs with a conven tional p-A1GaN EBL or a common n-A1GaN HBL. Meanwhile, the efficiency droop is alleviated when an n-A1GaN HBL with gradual A1 composition is used.
基金Project supported by the Special Strategic Emerging Industries of Guangdong Province,China(Grant No.2012A080304006)the Major Scientific and Technological Projects of Zhongshan City,Guangdong Province,China(Grant No.2014A2FC204)the Forefront of Technology Innovation and Key Technology Projects of Guangdong Province,China(Grant Nos.2014B010121001 and 2014B010119004)
文摘The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency（IQE）. The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells（QWs） enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.
基金the National Natural Science Foundation of China (Grant No. 39730130) and Chinese Academy of Sciences.
文摘Alterations of membrane lipid biophysical properties of sensitiveA549 and resistant A549/DDP cells to the Cis-dichlorodiammine platinum (Cisplatin) were performed by measurements of fluorescence and flow cytometry approaches using fluorescence dyes of DPH, N-AS and Merocyanine 540 (MC 540) respectively. Fatty acids of membrane lipid of the two cell lines were analyzed by gas chromatography. The results indicated clearly that fluorescence polarization (P) of the DPH probe is 0.169 for the sensitive A549 cell and 0.194 for the resistant A549/DDP cells. Statistical analysis showed significant difference between the two cell lines. The polarizations of 2-AS and 7-AS which reflect the fluidity of surface and middle of lipid bilayer are 0.134 and 0.144 for the sensitive A549 cells as well as 0.171 and 0.178 for the resistant A549/DDP cells respectively, but there is no significant difference of the polarization of 12-AS between the two cell lines. This shows that altera-tions of the membrane fluidity of both cells were mainly located on the surface and middle of the lipid bilayer. In addition, the packing density of phospholipid molecules in the membrane of the two cell lines detected by MC540 probe indicated that lipid packing of A549 cell membranes was looser than that of the A549/DDP cells. And unsaturation degree of plasma membrane fatty acids of the A549/DDP cells was also lower than that of A549 cells. Taken together, it was proposed that the al-teration of membrane lipid biophysical state may be involved in the resistance of A549/DDP cells to cisplatin.
