Results 51 to 60 of about 1,208 (99)

不同中性点接地方式雷击建弧率的研究

open access: yesDianci bileiqi
配电网线路繁多,覆盖范围广,易遭受雷电袭击,破坏力度大。通过建弧机理和熄弧特性分析,中性点不接地方式虽不易建弧,一旦建弧难于熄灭,当系统电容电流较大时仍会有较高的建弧率。消弧线圈接地方式下若补偿度不足或者较高时,会加大接地电弧重燃概率。小电阻接地方式下虽可防护弧光接地过电压,但无法识别故障性质,无法处理高阻接地故障。因此可根据配电网不同的线路结构优化中性点接地方式以降低雷击建弧率。不接地方式仅适用于电容电流小于10 A的以架空裸导线为主的配电网 ...
郝树青, 何肖蒙, 张洋, 李华鹏
doaj  

[Risks, mechanisms, and prevention strategies for cerebrovascular diseases in lunar astronauts under deep]. [PDF]

open access: yesZhong Nan Da Xue Xue Bao Yi Xue Ban
Tang L   +7 more
europepmc   +1 more source

基于PCA与PSO-SVM的谐振接地系统故障选线方法

open access: yesDianci bileiqi
为解决谐振接地系统单相接地故障对故障初始角为零以及接地电阻为高阻的故障线路识别效果差的问题,提出一种基于主成分分析与粒子群算法优化支持向量机(PCA-PSO-SVM)的选线方法。该方法通过Matlab/Simulink对小电流接地系统进行仿真,采集瞬时零序功率数据,将数据输入PCA-PSO-SVM模型中进行训练与测试,并将测试结果与单一的支持向量机模型以及经粒子群优化后的支持向量机模型进行对比,结果表明PCA-PSO-SVM模型有着更好的选线准确度与选线效率。
聂远航   +4 more
doaj  

[Medical treatment standards for emergency burn wounded (2025 edition)]. [PDF]

open access: yesZhongguo Xiu Fu Chong Jian Wai Ke Za Zhi
National Health Commission Of The People's Republic Of China.
europepmc   +1 more source

[Application of P1 response threshold of cortical auditory evoked potential in rehabilitation evaluation of young children with cochlear implant]. [PDF]

open access: yesLin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
Ji H   +6 more
europepmc   +1 more source

[Expert Consensus on Shared Decision-making in the Diagnosis and Treatment 
of Ground-glass Opacity-featured Lung Adenocarcinoma]. [PDF]

open access: yesZhongguo Fei Ai Za Zhi
Zhao X   +4 more
europepmc   +1 more source

[Survey on sleep status and OSA-18 questionnaire among preschool children in Zhongshan City]. [PDF]

open access: yesLin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
Xu C, Fu M, Pan Z, Luo J.
europepmc   +1 more source

基于模态路径层析法的接地网故障区域成像系统研究

open access: yesDianci bileiqi
为更高效、更准确地进行接地网故障诊断,本文提出基于模态路径层析法的接地网故障区域成像诊断模型。首先,将接地网拓扑结构变换成只含可及节点的模态路径网络图,依据连接支路数选择网络枢纽点,测量与其相连支路阻值并计算相对误差,选取相对误差最大点为下一层诊断节点,如此逐层剖析确定腐蚀区域;然后在该区域采用电阻抗成像技术(EIT)进行电导率二维成像;接着针对EIT技术成像精度受电导率初值分布影响较大的问题,提出采用改进的登山队优化算法(IMTBO)对电导率进行初值寻优 ...
常红阳, 王昕, 唐浩哲, 江恒
doaj  

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