为满足某系统高功率高效率固态功率放大器的需求,研制了L波段220 W高效率固态功率放大器。基于GaN高电子迁移率晶体管(HEMT)芯片,通过器件的内部匹配网络和外部匹配电路的优化,在C类工作状态下,实现了高效率的L波段160 W GaN功率器件;...为满足某系统高功率高效率固态功率放大器的需求,研制了L波段220 W高效率固态功率放大器。基于GaN高电子迁移率晶体管(HEMT)芯片,通过器件的内部匹配网络和外部匹配电路的优化,在C类工作状态下,实现了高效率的L波段160 W GaN功率器件;通过对多层结构宽边耦合器的仿真和介质材料的选用,设计了低损耗、高效率、大功率的合成器;通过对隔离变换电路和整流电路的改进,电源效率达到92%以上。该放大器末级器件采用功率合成的方式,最终饱和输出功率达到238.8 W(53.78 dBm),功率增益88 dB以上,功率附加效率达到60.9%。热仿真结果显示,在70℃壳温下,GaN功率器件结温为106℃,满足产品高可靠长寿命的需求。展开更多
For a mesoscopic L-C circuit,besides the Louisell's quantization scheme in which electric charge q andelectric current I are respectively quantized as the coordinate operator Q and momentum operator P,in this pape...For a mesoscopic L-C circuit,besides the Louisell's quantization scheme in which electric charge q andelectric current I are respectively quantized as the coordinate operator Q and momentum operator P,in this paperwe propose a new quantization scheme in the context of number-phase quantization through the standard Lagrangianformalism.The comparison between this number-phase quantization with the Josephson junction's Cooper pair number-phase-difference quantization scheme is made.展开更多
To develop a new DNA maker, which could be used in genetic diversity analysis and genetic map construction in plants, IT-ISJ （intron targeted intron-exon splice junction） primer combinations, which were designed acc...To develop a new DNA maker, which could be used in genetic diversity analysis and genetic map construction in plants, IT-ISJ （intron targeted intron-exon splice junction） primer combinations, which were designed according to the intronexon splice junction conserved sequences, were used to construct cotton genetic linkage map in the present study. 49 out of 704 IT-ISJ primer combinations showed polymorphism between upland cotton high quality cultivar Yumian 1 and multiple dominant gene line T586, and the polymorphic primer combinations accounted for 7.0% of total primer combinations. 49 IT-ISJ primer combinations were used to genotype 270 F2：7 recombinant inbred lines developed from （Yumian 1 × T586） F2, and 58 IT-ISJ loci were obtained. 58 IT-ISJ, together with 150 SSR and 8 morphological loci, were used to conduct linkage analysis, and a linkage map including 22 linkage groups and 113 loci （49 IT-ISJ, 62 SSR, and 2 morphological loci） was constructed. The linkage map covered 714.5 cM with an average interval of 6.3 cM between two markers, accounting for 16.1% of cotton genome. The present study demonstrated that the polymorphism of IT-ISJ marker is high, and it could be effectively applied in plant genetic map construction.展开更多
Combining flows often occur in open channel networks of drainage systems and river engineering. Open-channel junction flows were analyzed by solving the depth-averaged two-dimensional, elliptic Reynolds-averaged Navie...Combining flows often occur in open channel networks of drainage systems and river engineering. Open-channel junction flows were analyzed by solving the depth-averaged two-dimensional, elliptic Reynolds-averaged Navier-Stokes equations with the Hanjalic-Launder (H-L) modification to the k-ε turbulence model without the free surface “rigid lid” approximation with an efficient finite-volume procedure. The model can also analyze flows with separation. The model was used to analyze the relative importance of various factors and was compared with laboratory measurements. The H-L modification produced much better simulations of the separation zone size with 20% better accuracy than the standard k-ε model. The H-L modification was then used to study the characteristic of junction flows and the separation zones with different discharge ratios. The simulational results show that separation zone size decreases as the discharge ratio of the upstream main channel to the downstream channel increases.展开更多
基金The project supported by the President Foundation of the Chinese Academy of Sciences
文摘For a mesoscopic L-C circuit,besides the Louisell's quantization scheme in which electric charge q andelectric current I are respectively quantized as the coordinate operator Q and momentum operator P,in this paperwe propose a new quantization scheme in the context of number-phase quantization through the standard Lagrangianformalism.The comparison between this number-phase quantization with the Josephson junction's Cooper pair number-phase-difference quantization scheme is made.
基金the National Natural Science Foundation of China (30370898,30571187, 30871556)National High Tech Research and Development Program of China (2006AA10Z1D3,2006AA100105)
文摘To develop a new DNA maker, which could be used in genetic diversity analysis and genetic map construction in plants, IT-ISJ （intron targeted intron-exon splice junction） primer combinations, which were designed according to the intronexon splice junction conserved sequences, were used to construct cotton genetic linkage map in the present study. 49 out of 704 IT-ISJ primer combinations showed polymorphism between upland cotton high quality cultivar Yumian 1 and multiple dominant gene line T586, and the polymorphic primer combinations accounted for 7.0% of total primer combinations. 49 IT-ISJ primer combinations were used to genotype 270 F2：7 recombinant inbred lines developed from （Yumian 1 × T586） F2, and 58 IT-ISJ loci were obtained. 58 IT-ISJ, together with 150 SSR and 8 morphological loci, were used to conduct linkage analysis, and a linkage map including 22 linkage groups and 113 loci （49 IT-ISJ, 62 SSR, and 2 morphological loci） was constructed. The linkage map covered 714.5 cM with an average interval of 6.3 cM between two markers, accounting for 16.1% of cotton genome. The present study demonstrated that the polymorphism of IT-ISJ marker is high, and it could be effectively applied in plant genetic map construction.
文摘Combining flows often occur in open channel networks of drainage systems and river engineering. Open-channel junction flows were analyzed by solving the depth-averaged two-dimensional, elliptic Reynolds-averaged Navier-Stokes equations with the Hanjalic-Launder (H-L) modification to the k-ε turbulence model without the free surface “rigid lid” approximation with an efficient finite-volume procedure. The model can also analyze flows with separation. The model was used to analyze the relative importance of various factors and was compared with laboratory measurements. The H-L modification produced much better simulations of the separation zone size with 20% better accuracy than the standard k-ε model. The H-L modification was then used to study the characteristic of junction flows and the separation zones with different discharge ratios. The simulational results show that separation zone size decreases as the discharge ratio of the upstream main channel to the downstream channel increases.
