Based on the analysis of conditions for airflow reversal within a bypass branch, the airflow reversal phenomena were successfully simulated in the laboratory experiments. Data obtained indicate that airflow reversal w...Based on the analysis of conditions for airflow reversal within a bypass branch, the airflow reversal phenomena were successfully simulated in the laboratory experiments. Data obtained indicate that airflow reversal within a bypass branch is mainly caused by fire pressure yielded in the combustion branch. In addition, the maximum reversal quantity of airflow occurs in step with the highest temperature of fire, the highest concentration of CO 2 and the lowest concentration of O 2. Moreover, the time that fire size reaches the maximum value corresponds to the time airflow reversal in the bypass branch is most possible. The results are of great significance for guiding rescue work to avoid airflow reversal.展开更多
直流断路器作为柔性直流电网的关键设备,对直流输配电网的安全、稳定运行有着重要的意义。针对带限流能力的直流断路器存在的造价偏高、故障清除速度慢等问题,提出了一种带自充电支路的改进型混合直流断路器(improved hybrid DC circuit...直流断路器作为柔性直流电网的关键设备,对直流输配电网的安全、稳定运行有着重要的意义。针对带限流能力的直流断路器存在的造价偏高、故障清除速度慢等问题,提出了一种带自充电支路的改进型混合直流断路器(improved hybrid DC circuit breaker with self-charging branch,SCB-IHDCCB)拓扑,设置限流电感旁路和接地旁路,优化自充电支路路线,将泄能支路与自充电支路结合使用,在保证断路器性能的前提下,减少了支路数量,大大降低了晶闸管等元器件数量,从而大大降低其造价。对所提拓扑在单端系统中的工况进行了理论推导与分析,基于所提拓扑设计了500kV的单端直流系统,在PSCAD/EMTDC中建立模型进行了仿真验证,并与其他拓扑方案的性能、元器件数量进行比较。仿真结果表明,SCB-IHDCCB的性能和造价都得到较大优化,具有良好的经济性和应用前景。展开更多
目的探讨非体外循环下对单侧肺动脉起源于主动脉(anomalous origin of single pulmonary artery branch,AOSPA)施行矫治手术的疗效。方法 2004年1月～2009年10月对4例AOSPA在非体外循环下施行矫治手术,3例经正中开胸,1例经左侧切口。充...目的探讨非体外循环下对单侧肺动脉起源于主动脉(anomalous origin of single pulmonary artery branch,AOSPA)施行矫治手术的疗效。方法 2004年1月～2009年10月对4例AOSPA在非体外循环下施行矫治手术,3例经正中开胸,1例经左侧切口。充分游离异常起源的肺动脉,将其从主动脉侧切下。主肺动脉上侧壁钳,做横切口,将切下的异常起源的肺动脉端侧吻合于主肺动脉。结果 3例应用人工血管,1例用自体心包。手术时间分别为120、130、165、195 min,术后机械通气分别为10、8、10、25 h,无围术期死亡。4例分别随访16、39、92、56个月,无吻合口狭窄,肺动脉压正常2例,1例轻度肺动脉高压,1例中度肺动脉高压。结论对简单的一侧肺动脉起源异常患者,可以在非体外循环下进行矫治手术,操作简单,避免体外循环相关及肺部并发症,疗效满意。展开更多
基金National Natural Science Foundation of China( 5 9876 0 45 )
文摘Based on the analysis of conditions for airflow reversal within a bypass branch, the airflow reversal phenomena were successfully simulated in the laboratory experiments. Data obtained indicate that airflow reversal within a bypass branch is mainly caused by fire pressure yielded in the combustion branch. In addition, the maximum reversal quantity of airflow occurs in step with the highest temperature of fire, the highest concentration of CO 2 and the lowest concentration of O 2. Moreover, the time that fire size reaches the maximum value corresponds to the time airflow reversal in the bypass branch is most possible. The results are of great significance for guiding rescue work to avoid airflow reversal.
文摘直流断路器作为柔性直流电网的关键设备,对直流输配电网的安全、稳定运行有着重要的意义。针对带限流能力的直流断路器存在的造价偏高、故障清除速度慢等问题,提出了一种带自充电支路的改进型混合直流断路器(improved hybrid DC circuit breaker with self-charging branch,SCB-IHDCCB)拓扑,设置限流电感旁路和接地旁路,优化自充电支路路线,将泄能支路与自充电支路结合使用,在保证断路器性能的前提下,减少了支路数量,大大降低了晶闸管等元器件数量,从而大大降低其造价。对所提拓扑在单端系统中的工况进行了理论推导与分析,基于所提拓扑设计了500kV的单端直流系统,在PSCAD/EMTDC中建立模型进行了仿真验证,并与其他拓扑方案的性能、元器件数量进行比较。仿真结果表明,SCB-IHDCCB的性能和造价都得到较大优化,具有良好的经济性和应用前景。
