复合绝缘子在长期辐照、盐雾、鸟啄等因素的综合作用下,会产生伞裙护套破损及表面湿污等缺陷,威胁电力系统正常运行。文中搭建了基于EHP-50F电场传感器的绝缘子空间电场测试平台,建立了FXBW4-35/70棒形悬式复合绝缘子的1∶1三维仿真模型...复合绝缘子在长期辐照、盐雾、鸟啄等因素的综合作用下,会产生伞裙护套破损及表面湿污等缺陷,威胁电力系统正常运行。文中搭建了基于EHP-50F电场传感器的绝缘子空间电场测试平台,建立了FXBW4-35/70棒形悬式复合绝缘子的1∶1三维仿真模型,从试验和仿真两个方面研究了复合绝缘子伞裙护套破损及其表面存在湿污时的空间电场分布特征。结果表明:伞裙破损位置处空间电场强度下降,当破损位于低压侧时变化最大,试验和仿真值分别下降了23.29%和22.23%;护套破损位置处空间电场强度上升,且测量距离越小空间电场强度变化越大,当测量距离为3 cm时提高了0.098 k V/cm;破损绝缘子上的湿污会进一步畸变其场强,随ρES的增加该畸变程度增加,当ρES=1.5 mg/cm^(2)时,试验和仿真值分别提高了25.83%和23.35%。研究绝缘子伞裙护套破损及表面湿污情况下的空间电场分布特征对绝缘子表面状态监测等具有重要意义。展开更多
The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge ...The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge protection device is shown.展开更多
Objective:The perioperative period of major orthopedic surgery is associated with a high risk of thrombosis,but the best chemopreventive agent for thrombosis prophylaxis is still inconclusive.For this reason,this pape...Objective:The perioperative period of major orthopedic surgery is associated with a high risk of thrombosis,but the best chemopreventive agent for thrombosis prophylaxis is still inconclusive.For this reason,this paper evaluated the efficacy and safety of aspirin versus low-molecular heparin using a Meta-analysis.Methods:Ten randomized controlled studies on the application of aspirin and low-molecular heparin for the prevention of deep vein thrombosis in orthopedic major surgery were retrieved by computer searches of PubMed,CochraneLibrary,WebofScience,China Knowledge Network,Wanfang,and Vipul databases according to inclusion and exclusion criteria,and the literature was managed using Endnote software,and the data were analyzed using Revman 5.3 software was used to perform Meta-analysis of the extracted data,focusing on the effects of these two drugs on pulmonary embolism,deep vein thrombosis,major bleeding events,minor bleeding events,wound complications,mortality and blood loss within 90 days after major orthopedic surgery.Results:(1)Ten randomized controlled trials of high quality were included,with a total of 12,974 patients,7,026 in the aspirin group and 5,948 in the low-molecular heparin group;(2)Meta-analysis showed that aspirin had a higher incidence of pulmonary embolism(OR=1.59,95%CI:1.02 to 2.49,P=0.04)and deep vein thrombosis(OR=1.60,95%CI:1.26 to 2.02,P=0.0001)than low molecular heparin;(3)The incidence of major bleeding events(OR=0.85,95%CI:0.47 to 1.55,P=0.60),minor bleeding events(OR=0.79,95%CI:0.55 to 1.12,P=0.18),adverse wound reactions(OR=0.79,95%CI:0.48 to 1.31,P=0.36),mortality within 90 days(OR=0.69,95%CI:0.20 to 2.31,P=0.55)and perioperative blood loss(MD=0.69,95%CI:0.20 to 2.31,P=0.55)in both drug groups,mortality within 90 days(OR=0.69,95%CI:0.20 to 2.31,P=0.55)and perioperative blood loss(MD=0.69,95%CI:0.20 to 2.31,P=0.55)were not statistically significant.Conclusion:Low-molecular heparin was superior to aspirin in the prevention of pulmonary embolism and lower extremity deep vein thrombosis after major orthopedic surgery,but the safety and adverse drug reactions of both groups were basically similar.Based on this,the authors recommend that low-molecular heparin should be preferred for the prevention of deep vein thrombosis in major orthopaedic surgery;however,the inclusion of randomized controlled trials remains limited,necessitating high-quality,large-sample,long-term follow-up clinical studies.展开更多
文摘复合绝缘子在长期辐照、盐雾、鸟啄等因素的综合作用下,会产生伞裙护套破损及表面湿污等缺陷,威胁电力系统正常运行。文中搭建了基于EHP-50F电场传感器的绝缘子空间电场测试平台,建立了FXBW4-35/70棒形悬式复合绝缘子的1∶1三维仿真模型,从试验和仿真两个方面研究了复合绝缘子伞裙护套破损及其表面存在湿污时的空间电场分布特征。结果表明:伞裙破损位置处空间电场强度下降,当破损位于低压侧时变化最大,试验和仿真值分别下降了23.29%和22.23%;护套破损位置处空间电场强度上升,且测量距离越小空间电场强度变化越大,当测量距离为3 cm时提高了0.098 k V/cm;破损绝缘子上的湿污会进一步畸变其场强,随ρES的增加该畸变程度增加,当ρES=1.5 mg/cm^(2)时,试验和仿真值分别提高了25.83%和23.35%。研究绝缘子伞裙护套破损及表面湿污情况下的空间电场分布特征对绝缘子表面状态监测等具有重要意义。
文摘The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge protection device is shown.
基金Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2019D01C244)Special Research Project for Health and Young Medical Science and Technology Talents in Xinjiang Uygur Autonomous Region(No.WJWY-202142)。
文摘Objective:The perioperative period of major orthopedic surgery is associated with a high risk of thrombosis,but the best chemopreventive agent for thrombosis prophylaxis is still inconclusive.For this reason,this paper evaluated the efficacy and safety of aspirin versus low-molecular heparin using a Meta-analysis.Methods:Ten randomized controlled studies on the application of aspirin and low-molecular heparin for the prevention of deep vein thrombosis in orthopedic major surgery were retrieved by computer searches of PubMed,CochraneLibrary,WebofScience,China Knowledge Network,Wanfang,and Vipul databases according to inclusion and exclusion criteria,and the literature was managed using Endnote software,and the data were analyzed using Revman 5.3 software was used to perform Meta-analysis of the extracted data,focusing on the effects of these two drugs on pulmonary embolism,deep vein thrombosis,major bleeding events,minor bleeding events,wound complications,mortality and blood loss within 90 days after major orthopedic surgery.Results:(1)Ten randomized controlled trials of high quality were included,with a total of 12,974 patients,7,026 in the aspirin group and 5,948 in the low-molecular heparin group;(2)Meta-analysis showed that aspirin had a higher incidence of pulmonary embolism(OR=1.59,95%CI:1.02 to 2.49,P=0.04)and deep vein thrombosis(OR=1.60,95%CI:1.26 to 2.02,P=0.0001)than low molecular heparin;(3)The incidence of major bleeding events(OR=0.85,95%CI:0.47 to 1.55,P=0.60),minor bleeding events(OR=0.79,95%CI:0.55 to 1.12,P=0.18),adverse wound reactions(OR=0.79,95%CI:0.48 to 1.31,P=0.36),mortality within 90 days(OR=0.69,95%CI:0.20 to 2.31,P=0.55)and perioperative blood loss(MD=0.69,95%CI:0.20 to 2.31,P=0.55)in both drug groups,mortality within 90 days(OR=0.69,95%CI:0.20 to 2.31,P=0.55)and perioperative blood loss(MD=0.69,95%CI:0.20 to 2.31,P=0.55)were not statistically significant.Conclusion:Low-molecular heparin was superior to aspirin in the prevention of pulmonary embolism and lower extremity deep vein thrombosis after major orthopedic surgery,but the safety and adverse drug reactions of both groups were basically similar.Based on this,the authors recommend that low-molecular heparin should be preferred for the prevention of deep vein thrombosis in major orthopaedic surgery;however,the inclusion of randomized controlled trials remains limited,necessitating high-quality,large-sample,long-term follow-up clinical studies.
