研究一种基于多模块多电平双向DC-DC变换器的超级电容储能系统,该系统可有助于减小超级电容单体电压低与应用场合电压高间的矛盾。超级电容组间的均压控制是该系统稳定运行的关键之一。对超级电容组的均压控制和储能系统能量管理策略进...研究一种基于多模块多电平双向DC-DC变换器的超级电容储能系统,该系统可有助于减小超级电容单体电压低与应用场合电压高间的矛盾。超级电容组间的均压控制是该系统稳定运行的关键之一。对超级电容组的均压控制和储能系统能量管理策略进行分析和设计。利用双向变换器的小信号模型分析超级电容储能系统电流控制与超级电容组间均压控制的关系,设计多模块多电平双向DC-DC变换器的双闭环控制策略,在稳定控制网侧电感电流的同时实现超级电容组间电压均衡的解耦控制。进一步,根据母线电压变化及超级电容荷电水平(state of charge,SOC)提出储能系统能量控制策略。系统仿真和实验验证了所提出的基于MMC双向变换器的超级电容储能系统控制策略的有效性。展开更多
美国国防部高级研究计划局(Defense Advanced Research Projects Agency,DARPA)先进技术开发项目是研发目标明确、项目体量大、综合性强的任务导向型项目。基于科技项目生命周期过程管理研究基础,建立了科技项目管理分析框架,选取DARPA...美国国防部高级研究计划局(Defense Advanced Research Projects Agency,DARPA)先进技术开发项目是研发目标明确、项目体量大、综合性强的任务导向型项目。基于科技项目生命周期过程管理研究基础,建立了科技项目管理分析框架,选取DARPA高空长航时无人机项目为典型案例,从项目选题、项目立项、项目实施、项目验收与转化4个阶段对DARPA先进技术开发项目管理实践进行梳理,总结了DARPA开展此类任务导向型科技项目的管理经验,以期为中国相关科技项目管理工作提供参考。展开更多
<strong>Background:</strong> Postpartum haemorrhage is the leading cause of maternal deaths worldwide, the majority of which occur in low resource settings. Uterine atony is the commonest cause of postpart...<strong>Background:</strong> Postpartum haemorrhage is the leading cause of maternal deaths worldwide, the majority of which occur in low resource settings. Uterine atony is the commonest cause of postpartum haemorrhage. Uterine balloon tamponade (UBT) is an effective method of treating refractory postpartum haemorrhage.<strong> Aim:</strong> Commercial UBT devices are often not affordable and not readily available in rural settings. The aim of this paper is to report on three cases of postpartum haemorrhage successfully managed with uterine balloon tamponade using Foley catheters. <strong>Case Reports:</strong> We report on three patients with major obstetric haemorrhage from uterine atony who were successfully managed with uterine balloon tamponade using Foley’s urethral catheter. The first two patients had primary postpartum haemorrhage while the third patient had significant bleeding during the surgical evacuation of the uterus for a molar pregnancy. In each case, uterine bleeding was refractory to pharmacologic uterotonics. They all had uterine tamponade with a Foley catheter with the dramatic resolution of their bleeding. <strong>Conclusion:</strong> In well-selected patients, uterine balloon tamponade with Foley catheter is cheap, arrests bleeding and prevents clinical deterioration among women with refractory postpartum haemorrhage, especially in low resource settings where commercial balloon tamponade may not be available or affordable.展开更多
Li Peng,an excellent first-line manager,is the deputy security director of Changqing Branch of China Petroleum Logging Co.,Ltd.He was awarded the National May 1st Labour Medal in 2013,participated in five scientific r...Li Peng,an excellent first-line manager,is the deputy security director of Changqing Branch of China Petroleum Logging Co.,Ltd.He was awarded the National May 1st Labour Medal in 2013,participated in five scientific research projects,and obtained one authorised national utility model patent.展开更多
文摘研究一种基于多模块多电平双向DC-DC变换器的超级电容储能系统,该系统可有助于减小超级电容单体电压低与应用场合电压高间的矛盾。超级电容组间的均压控制是该系统稳定运行的关键之一。对超级电容组的均压控制和储能系统能量管理策略进行分析和设计。利用双向变换器的小信号模型分析超级电容储能系统电流控制与超级电容组间均压控制的关系,设计多模块多电平双向DC-DC变换器的双闭环控制策略,在稳定控制网侧电感电流的同时实现超级电容组间电压均衡的解耦控制。进一步,根据母线电压变化及超级电容荷电水平(state of charge,SOC)提出储能系统能量控制策略。系统仿真和实验验证了所提出的基于MMC双向变换器的超级电容储能系统控制策略的有效性。
文摘美国国防部高级研究计划局(Defense Advanced Research Projects Agency,DARPA)先进技术开发项目是研发目标明确、项目体量大、综合性强的任务导向型项目。基于科技项目生命周期过程管理研究基础,建立了科技项目管理分析框架,选取DARPA高空长航时无人机项目为典型案例,从项目选题、项目立项、项目实施、项目验收与转化4个阶段对DARPA先进技术开发项目管理实践进行梳理,总结了DARPA开展此类任务导向型科技项目的管理经验,以期为中国相关科技项目管理工作提供参考。
文摘<strong>Background:</strong> Postpartum haemorrhage is the leading cause of maternal deaths worldwide, the majority of which occur in low resource settings. Uterine atony is the commonest cause of postpartum haemorrhage. Uterine balloon tamponade (UBT) is an effective method of treating refractory postpartum haemorrhage.<strong> Aim:</strong> Commercial UBT devices are often not affordable and not readily available in rural settings. The aim of this paper is to report on three cases of postpartum haemorrhage successfully managed with uterine balloon tamponade using Foley catheters. <strong>Case Reports:</strong> We report on three patients with major obstetric haemorrhage from uterine atony who were successfully managed with uterine balloon tamponade using Foley’s urethral catheter. The first two patients had primary postpartum haemorrhage while the third patient had significant bleeding during the surgical evacuation of the uterus for a molar pregnancy. In each case, uterine bleeding was refractory to pharmacologic uterotonics. They all had uterine tamponade with a Foley catheter with the dramatic resolution of their bleeding. <strong>Conclusion:</strong> In well-selected patients, uterine balloon tamponade with Foley catheter is cheap, arrests bleeding and prevents clinical deterioration among women with refractory postpartum haemorrhage, especially in low resource settings where commercial balloon tamponade may not be available or affordable.
文摘Li Peng,an excellent first-line manager,is the deputy security director of Changqing Branch of China Petroleum Logging Co.,Ltd.He was awarded the National May 1st Labour Medal in 2013,participated in five scientific research projects,and obtained one authorised national utility model patent.
