风电变流器(wind power converter,WPC)是风电转换系统的关键部件,承担着风机功率变换和并网的重要功能。WPC故障会造成整个风电机组停运,其可靠性高低对风电转换系统乃至整个风电场的可靠性都有较大影响。由于海上风电场运行环境恶劣,...风电变流器(wind power converter,WPC)是风电转换系统的关键部件,承担着风机功率变换和并网的重要功能。WPC故障会造成整个风电机组停运,其可靠性高低对风电转换系统乃至整个风电场的可靠性都有较大影响。由于海上风电场运行环境恶劣,故障元件的维修与更换困难,WPC对海上风电场整体可靠性的影响也更为严重。基于WPC的故障机理,建立了计及WPC故障的海上风电场风电转换系统可靠性模型。基于该模型,进一步考虑风机尾流效应和风电场集电系统的故障,对海上风电场进行了可靠性评估,研究了WPC故障对海上风电场整体可靠性的影响,并对影响变流器和海上风电场可靠性的主要因素进行了灵敏度分析。算例结果表明,风电机组变流器故障对海上风电场整体可靠性的影响较大,在计及变流器故障的影响后,海上风电场的容量因子将显著降低。展开更多
The China JinPing underground Laboratory （CJPL） is the deepest underground laboratory running in the world at present. In such a deep underground laboratory, the cosmic ray flux is a very important and necessary par...The China JinPing underground Laboratory （CJPL） is the deepest underground laboratory running in the world at present. In such a deep underground laboratory, the cosmic ray flux is a very important and necessary parameter for rare-event experiments. A plastic scintillator telescope system has been set up to measure the cosmic ray flux. The performance of the telescope system has been studied using the cosmic rays on the ground laboratory near the CJPL. Based on the underground experimental data taken from November 2010 to December 2011 in the CJPL, which has an effective live time of 171 days, the cosmic ray muon flux in the CJPL is measured to be （2.0±0.4）×10^-10/（cm2.s）. The ultra-low cosmic ray background guarantees an ideal environment for dark matter experiments at the CJPL.展开更多
[目的]探讨椎体后凸成形术治疗老年人无神经症状不完全性胸腰段爆裂性骨折的安全性及其疗效。[方法]椎体后凸成形术试行治疗18例无神经症状的老年人胸腰段爆裂性骨折(Magerl分型:A3.1)。术中采用体位复位及逐步球囊扩张技术,在C型臂X线...[目的]探讨椎体后凸成形术治疗老年人无神经症状不完全性胸腰段爆裂性骨折的安全性及其疗效。[方法]椎体后凸成形术试行治疗18例无神经症状的老年人胸腰段爆裂性骨折(Magerl分型:A3.1)。术中采用体位复位及逐步球囊扩张技术,在C型臂X线机动态观察下灌注骨水泥。术前、术后及术后12个月时采用疼痛视觉模拟评分(visual analog score,VAS)评估疼痛程度,并测量术前、术后及术后12个月时骨折椎体前缘高度比、Cobb角及椎管内骨块占位率。[结果]手术操作顺利,术后无神经损伤的并发症发生,患者症状迅速缓解。患者VAS评分平均由术前(8.17±0.618)分降为术后(2.33±0.767)分(P<0.05),术后12个月随访时维持在(2.39±0.698)分。椎体前缘高度从平均73.72%±6.153%纠正为术后的92.78%±1.927%(P<0.05),术后12个月为92.33%±1.534%;Cobb角由术前平均20.50°±2.333°改善为6.00°±1.847°(P<0.05),术后12月随访Cobb角部分丢失为8.83°±2.056°(P<0.05)。椎管内骨块占位率术前平均为16.22%±4.387%,而术后为15.56%±4.162%(P>0.05)。[结论]在C型臂X线机动态观察下,利用体位复位结合球囊分次逐步扩张技术,椎体后凸成形术治疗无神经症状的老年人胸腰段不完全性爆裂性骨折手术安全、疗效满意。展开更多
文摘风电变流器(wind power converter,WPC)是风电转换系统的关键部件,承担着风机功率变换和并网的重要功能。WPC故障会造成整个风电机组停运,其可靠性高低对风电转换系统乃至整个风电场的可靠性都有较大影响。由于海上风电场运行环境恶劣,故障元件的维修与更换困难,WPC对海上风电场整体可靠性的影响也更为严重。基于WPC的故障机理,建立了计及WPC故障的海上风电场风电转换系统可靠性模型。基于该模型,进一步考虑风机尾流效应和风电场集电系统的故障,对海上风电场进行了可靠性评估,研究了WPC故障对海上风电场整体可靠性的影响,并对影响变流器和海上风电场可靠性的主要因素进行了灵敏度分析。算例结果表明,风电机组变流器故障对海上风电场整体可靠性的影响较大,在计及变流器故障的影响后,海上风电场的容量因子将显著降低。
基金Supported by National Natural Science Foundation of China (10935005, 11055002, 11075090)
文摘The China JinPing underground Laboratory （CJPL） is the deepest underground laboratory running in the world at present. In such a deep underground laboratory, the cosmic ray flux is a very important and necessary parameter for rare-event experiments. A plastic scintillator telescope system has been set up to measure the cosmic ray flux. The performance of the telescope system has been studied using the cosmic rays on the ground laboratory near the CJPL. Based on the underground experimental data taken from November 2010 to December 2011 in the CJPL, which has an effective live time of 171 days, the cosmic ray muon flux in the CJPL is measured to be （2.0±0.4）×10^-10/（cm2.s）. The ultra-low cosmic ray background guarantees an ideal environment for dark matter experiments at the CJPL.
文摘[目的]探讨椎体后凸成形术治疗老年人无神经症状不完全性胸腰段爆裂性骨折的安全性及其疗效。[方法]椎体后凸成形术试行治疗18例无神经症状的老年人胸腰段爆裂性骨折(Magerl分型:A3.1)。术中采用体位复位及逐步球囊扩张技术,在C型臂X线机动态观察下灌注骨水泥。术前、术后及术后12个月时采用疼痛视觉模拟评分(visual analog score,VAS)评估疼痛程度,并测量术前、术后及术后12个月时骨折椎体前缘高度比、Cobb角及椎管内骨块占位率。[结果]手术操作顺利,术后无神经损伤的并发症发生,患者症状迅速缓解。患者VAS评分平均由术前(8.17±0.618)分降为术后(2.33±0.767)分(P<0.05),术后12个月随访时维持在(2.39±0.698)分。椎体前缘高度从平均73.72%±6.153%纠正为术后的92.78%±1.927%(P<0.05),术后12个月为92.33%±1.534%;Cobb角由术前平均20.50°±2.333°改善为6.00°±1.847°(P<0.05),术后12月随访Cobb角部分丢失为8.83°±2.056°(P<0.05)。椎管内骨块占位率术前平均为16.22%±4.387%,而术后为15.56%±4.162%(P>0.05)。[结论]在C型臂X线机动态观察下,利用体位复位结合球囊分次逐步扩张技术,椎体后凸成形术治疗无神经症状的老年人胸腰段不完全性爆裂性骨折手术安全、疗效满意。
