The Triassic was a crucial period in the tectonic evolution of the South China Block.Research on tectonic deformation during this period provides information on intracontinental orogenic mechanisms in South China.In t...The Triassic was a crucial period in the tectonic evolution of the South China Block.Research on tectonic deformation during this period provides information on intracontinental orogenic mechanisms in South China.In this study,alongside thermochronological analyses,we examine the macroscopic and microscopic structural features of the Rongxian ductile shear zone,located south of the Darongshan granite in the southeastern part of Guangxi Province,on the southern margin of South China.Sinistral shear is indicated by the characteristics of rotatedσ-type feldspar porphyroclasts,stretching lineations defined by elongated quartz grains and the orientations of quartz c-axes.LA-ICP-MS U-Pb dating of zircons from two samples of granitic mylonite and one of granite yielded ages of ca.256 Ma.Furthermore,two samples of granitic mylonite yield muscovite^(40)Ar/^(39)Ar plateau ages of 249-246 Ma.These results indicate that the Rongxian ductile shear zone resulted from Early Triassic deformation of the late Permian Darongshan granite.This deformation was likely related to the closure of the eastern Paleo-Tethys Ocean and the subsequent collision of the South China and Indochina blocks,during the early stage of the Indosinian orogeny.展开更多
为了提高混合动力有轨电车制动过程中制动能量的回收效率,提出一种考虑储能系统始末状态的能量管理策略.在有轨电车从启动到制动的运行过程中,基于极小值原理对混合动力系统进行功率分配,以实现对超级电容荷电状态(state of charge,SOC...为了提高混合动力有轨电车制动过程中制动能量的回收效率,提出一种考虑储能系统始末状态的能量管理策略.在有轨电车从启动到制动的运行过程中,基于极小值原理对混合动力系统进行功率分配,以实现对超级电容荷电状态(state of charge,SOC)安全范围的有效控制,并保证在制动时刻超级电容具有足够的SOC余量来吸收制动功率;同时,将有轨电车启动、运行过程中的牵引控制策略与制动过程的能量回收策略相结合,采用绝缘栅门极晶体管(insulated gate bipolar translator,IGBT)斩波器与制动电阻相结合使用的方式,抑制母线电压的抬升;最后基于实际的有轨电车运行工况,在MATLAB/Simulink平台下进行了仿真测试.结果显示,在有轨电车制动时刻,超级电容SOC均能够按照预期下降到0.4左右,且在制动全过程中,有轨电车母线电压始终处于875 V以下,满足母线电压的控制要求.展开更多
为保证燃料电池系统在负载工况变化条件下仍能无扰动地运行在最大效率点,提出一种基于遗忘因子递推最小二乘(forgetting factor recursive least square,FFRLS)在线辨识和Super-Twisting滑模算法的燃料电池系统实时最大效率跟踪方法。...为保证燃料电池系统在负载工况变化条件下仍能无扰动地运行在最大效率点,提出一种基于遗忘因子递推最小二乘(forgetting factor recursive least square,FFRLS)在线辨识和Super-Twisting滑模算法的燃料电池系统实时最大效率跟踪方法。该方法基于非线性曲线拟合原理,根据系统实时测量数据,在单位控制周期内实现对燃料电池最大效率点功率的实时估计。采用Super-Twisting滑模算法,保证燃料电池系统在负载工况变化情况下仍能运行在最大效率点。在搭建的测试平台上,开展了多指标性能测试与对比分析。实验结果表明,与扰动观测(perturb and observe,P&O)算法相比,所提出的方法优势更加明显。另外,针对燃料电池输出存在大扰动问题,与PID控制效果进行了对比实验。实验结果显示:Super-Twisting滑模控制变换器在输入电压大扰动下具有较强的鲁棒性,有利于燃料电池系统长期稳定运行。展开更多
目的分析颅脑手术后发生颅内感染的相关危险因素,为减少颅脑手术后发生颅内感染提供依据。方法检索Web of Science、PubMed、Scopuss、Karger、EBSCO+Medline、Embase、中国知网、万方、维普数据库所收录的颅脑术后并发颅内感染的相关文...目的分析颅脑手术后发生颅内感染的相关危险因素,为减少颅脑手术后发生颅内感染提供依据。方法检索Web of Science、PubMed、Scopuss、Karger、EBSCO+Medline、Embase、中国知网、万方、维普数据库所收录的颅脑术后并发颅内感染的相关文献,检索时间为2009-2018年,采用Newcastle-Ottawa Scale(NOS)量表评价文献,采用STATA12.0分析数据。结果最终纳入符合条件的研究30项,共计36 773例患者。分析结果显示,颅脑手术后发生颅内感染的危险因素包括切口类型、二次手术、术后格拉斯哥昏迷评分(GCS评分)、术后脑脊液漏、手术时间、术中留置引流,而年龄、合并糖尿病、预防性使用抗菌药物、手术部位、急诊手术与术后发生颅内感染无关。围手术期使用激素与颅脑术后发生颅内感染存在争议。结论避免再次手术、脑脊液漏、不必要的引流,以及缩短手术时间将利于减少颅内感染发生,对于污染切口及术后GCS评分小于8分的患者更需警惕颅脑术后发生颅内感染。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42262026,42072259).
文摘The Triassic was a crucial period in the tectonic evolution of the South China Block.Research on tectonic deformation during this period provides information on intracontinental orogenic mechanisms in South China.In this study,alongside thermochronological analyses,we examine the macroscopic and microscopic structural features of the Rongxian ductile shear zone,located south of the Darongshan granite in the southeastern part of Guangxi Province,on the southern margin of South China.Sinistral shear is indicated by the characteristics of rotatedσ-type feldspar porphyroclasts,stretching lineations defined by elongated quartz grains and the orientations of quartz c-axes.LA-ICP-MS U-Pb dating of zircons from two samples of granitic mylonite and one of granite yielded ages of ca.256 Ma.Furthermore,two samples of granitic mylonite yield muscovite^(40)Ar/^(39)Ar plateau ages of 249-246 Ma.These results indicate that the Rongxian ductile shear zone resulted from Early Triassic deformation of the late Permian Darongshan granite.This deformation was likely related to the closure of the eastern Paleo-Tethys Ocean and the subsequent collision of the South China and Indochina blocks,during the early stage of the Indosinian orogeny.
文摘为保证燃料电池系统在负载工况变化条件下仍能无扰动地运行在最大效率点,提出一种基于遗忘因子递推最小二乘(forgetting factor recursive least square,FFRLS)在线辨识和Super-Twisting滑模算法的燃料电池系统实时最大效率跟踪方法。该方法基于非线性曲线拟合原理,根据系统实时测量数据,在单位控制周期内实现对燃料电池最大效率点功率的实时估计。采用Super-Twisting滑模算法,保证燃料电池系统在负载工况变化情况下仍能运行在最大效率点。在搭建的测试平台上,开展了多指标性能测试与对比分析。实验结果表明,与扰动观测(perturb and observe,P&O)算法相比,所提出的方法优势更加明显。另外,针对燃料电池输出存在大扰动问题,与PID控制效果进行了对比实验。实验结果显示:Super-Twisting滑模控制变换器在输入电压大扰动下具有较强的鲁棒性,有利于燃料电池系统长期稳定运行。
文摘目的分析颅脑手术后发生颅内感染的相关危险因素,为减少颅脑手术后发生颅内感染提供依据。方法检索Web of Science、PubMed、Scopuss、Karger、EBSCO+Medline、Embase、中国知网、万方、维普数据库所收录的颅脑术后并发颅内感染的相关文献,检索时间为2009-2018年,采用Newcastle-Ottawa Scale(NOS)量表评价文献,采用STATA12.0分析数据。结果最终纳入符合条件的研究30项,共计36 773例患者。分析结果显示,颅脑手术后发生颅内感染的危险因素包括切口类型、二次手术、术后格拉斯哥昏迷评分(GCS评分)、术后脑脊液漏、手术时间、术中留置引流,而年龄、合并糖尿病、预防性使用抗菌药物、手术部位、急诊手术与术后发生颅内感染无关。围手术期使用激素与颅脑术后发生颅内感染存在争议。结论避免再次手术、脑脊液漏、不必要的引流,以及缩短手术时间将利于减少颅内感染发生,对于污染切口及术后GCS评分小于8分的患者更需警惕颅脑术后发生颅内感染。
