In this paper we report on an experimental study of the characteristics of nanosecond pulsed discharge plasma aerodynamic actuation. The N2 （C3IIu） rotational and vibrational temperatures are around 430 K and 0.24 e...In this paper we report on an experimental study of the characteristics of nanosecond pulsed discharge plasma aerodynamic actuation. The N2 （C3IIu） rotational and vibrational temperatures are around 430 K and 0.24 eV, respectively. The emission intensity ratio between tile first negative system and the second positive system of N2, as a rough indicator of the temporally and spatially averaged electron energy, has a minor dependence on applied voltage amplitude. The induced flow direction is not parallel, but vertical to the dielectric layer surface, as shown by measurements of body force, velocity, and vorticity. Nanosecond discharge plasma aerodynamic actuation is effective in airfoil flow separation control at freestream speeds up to 100 m/s.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50906100 and 10972236)the Science Foundation of National Excellent Doctoral Dissertation of China (Grant No. 201172)
文摘In this paper we report on an experimental study of the characteristics of nanosecond pulsed discharge plasma aerodynamic actuation. The N2 （C3IIu） rotational and vibrational temperatures are around 430 K and 0.24 eV, respectively. The emission intensity ratio between tile first negative system and the second positive system of N2, as a rough indicator of the temporally and spatially averaged electron energy, has a minor dependence on applied voltage amplitude. The induced flow direction is not parallel, but vertical to the dielectric layer surface, as shown by measurements of body force, velocity, and vorticity. Nanosecond discharge plasma aerodynamic actuation is effective in airfoil flow separation control at freestream speeds up to 100 m/s.
文摘目的系统评价直接口服抗凝药(DOAC)在静脉血栓栓塞症(VTE)合并肿瘤患者中应用的有效性与安全性。方法构建检索策略,检索The Cochrane Library、PubMed、Embase、CNKI、万方数据库和中国生物医学文献数据库(CBM)。按纳入与排除标准筛选文献、提取资料并评价纳入研究的方法学质量后,采用Rev Man 5.3软件进行Meta分析。结果7项随机对照试验被纳入分析,包括5498例患者(试验组3115例,对照组2383例)。试验组药物包括利伐沙班、阿哌沙班、依度沙班和达比加群,对照组方案为肠外抗凝剂桥接维生素K拮抗剂(VKA)或肠外抗凝剂单独应用。3项随机对照试验(RCTs)显示DOAC组在VTE复发率上显著低于VKA组[NNT=36,OR=0.59,95%CI:0.40~0.86,P=0.006],2项RCTs显示DOAC组在VTE复发率上显著低于肠外抗凝剂组[NNT=26,OR=0.61,95%CI:0.42~0.89,P=0.01]。5项RCTs显示DOCA组在主要出血事件发生率上与VKA组差异无统计学意义[NNT=71,OR=0.68,95%CI:0.45~1.04,P=0.07],2项RCTs显示DOAC组在主要出血事件发生率上显著高于肠外抗凝剂组[NNT=36,OR=1.80,95%CI:1.11~2.92,P=0.02]。结论根据现有证据,在VTE合并肿瘤的患者中,DOAC防止VTE复发的效果最优;安全性方面与VKA差异不明显,但劣于肠外抗凝剂。
