方位编码器是二次雷达设备的重要部件,用于确定雷达天线波束中心的指向角。SELEX SIR-S二次雷达使用的编码器型号CODECHAMP COI 25002A,是14位增量式编码器。SELEX雷达对编码器有完备的脉冲处理、状态监视和控制电路。本文针对可能出现...方位编码器是二次雷达设备的重要部件,用于确定雷达天线波束中心的指向角。SELEX SIR-S二次雷达使用的编码器型号CODECHAMP COI 25002A,是14位增量式编码器。SELEX雷达对编码器有完备的脉冲处理、状态监视和控制电路。本文针对可能出现的编码器故障,总结了更换编码器的调试过程。展开更多
为了解决微波无线输能系统中微波源的小型化和高效率需求,提出了一种高效谐波调谐功率振荡器的设计方法,振荡器由晶体管、谐波控制网络、反馈网络和负载网络组成。首先,通过调谐晶体管谐波阻抗以减少漏极电压与电流波形的重叠,从而提高...为了解决微波无线输能系统中微波源的小型化和高效率需求,提出了一种高效谐波调谐功率振荡器的设计方法,振荡器由晶体管、谐波控制网络、反馈网络和负载网络组成。首先,通过调谐晶体管谐波阻抗以减少漏极电压与电流波形的重叠,从而提高其效率;其次,反馈网络与负载网络使用仿真获得的数据合成,两者可独立设计,避免了反馈回路对振荡器输出效率的影响。使用Cree CGH40010F GaN HEMT设计并制作了一款工作在S波段的高效功率振荡器,测试结果表明振荡器在2.445 GHz下成功实现了41.7 dBm的输出功率和79.9%的直流到射频(direct current to radio frequency,DC-RF)转化效率,在偏移载波1 MHz处,相位噪声低至-136 dBc/Hz。该功率振荡器性能优越,在微波无线能量传输系统中具有良好的应用前景。展开更多
Numerous theories of how and why aging occurs have been postulated but a definitive comprehensive explanation remains elusive. Attempts to unravel genetic details of aging resulted in the identification of a yeast gen...Numerous theories of how and why aging occurs have been postulated but a definitive comprehensive explanation remains elusive. Attempts to unravel genetic details of aging resulted in the identification of a yeast gene known as Sir2 as a modulator of life span. Identification and characterization of mammalian Sir2 homologs followed and has catapulted aging research to exciting new levels. This review begins with basic definitions of aging and then describes some of the most common theories of the aging process. The review presents information related to the initial discovery of the Sirtuins and summarizes some of the recent advances in defining roles for Sirtuin family members. SIRT6 is discussed in greater detail because it is one of the best characterized of the mammalian Sirtuins and seems to be one of the most important in the aging process and metabolic regulation.展开更多
文摘方位编码器是二次雷达设备的重要部件,用于确定雷达天线波束中心的指向角。SELEX SIR-S二次雷达使用的编码器型号CODECHAMP COI 25002A,是14位增量式编码器。SELEX雷达对编码器有完备的脉冲处理、状态监视和控制电路。本文针对可能出现的编码器故障,总结了更换编码器的调试过程。
文摘为了解决微波无线输能系统中微波源的小型化和高效率需求,提出了一种高效谐波调谐功率振荡器的设计方法,振荡器由晶体管、谐波控制网络、反馈网络和负载网络组成。首先,通过调谐晶体管谐波阻抗以减少漏极电压与电流波形的重叠,从而提高其效率;其次,反馈网络与负载网络使用仿真获得的数据合成,两者可独立设计,避免了反馈回路对振荡器输出效率的影响。使用Cree CGH40010F GaN HEMT设计并制作了一款工作在S波段的高效功率振荡器,测试结果表明振荡器在2.445 GHz下成功实现了41.7 dBm的输出功率和79.9%的直流到射频(direct current to radio frequency,DC-RF)转化效率,在偏移载波1 MHz处,相位噪声低至-136 dBc/Hz。该功率振荡器性能优越,在微波无线能量传输系统中具有良好的应用前景。
文摘Numerous theories of how and why aging occurs have been postulated but a definitive comprehensive explanation remains elusive. Attempts to unravel genetic details of aging resulted in the identification of a yeast gene known as Sir2 as a modulator of life span. Identification and characterization of mammalian Sir2 homologs followed and has catapulted aging research to exciting new levels. This review begins with basic definitions of aging and then describes some of the most common theories of the aging process. The review presents information related to the initial discovery of the Sirtuins and summarizes some of the recent advances in defining roles for Sirtuin family members. SIRT6 is discussed in greater detail because it is one of the best characterized of the mammalian Sirtuins and seems to be one of the most important in the aging process and metabolic regulation.
