针对复杂工业生产过程具有高维度、多工况、非线性的特征以及扩散映射存在的新样本投影困难的问题,本文提出了一种基于可扩容式扩散映射和局部离群因子(expandable diffusion maps and local outlier factors, EDM-LOF)的工业过程故障...针对复杂工业生产过程具有高维度、多工况、非线性的特征以及扩散映射存在的新样本投影困难的问题,本文提出了一种基于可扩容式扩散映射和局部离群因子(expandable diffusion maps and local outlier factors, EDM-LOF)的工业过程故障检测方法.使用扩散映射方法提取训练样本的低维流形结构,构建局部投影矩阵将新样本投影至流形空间,并在流形空间中使用局部离群因子方法进行故障检测.将EDM-LOF应用于青霉素发酵过程进行故障检测,并与PCA、FD-kNN、LOF方法进行比较,结果表明EDM-LOF具有更高的故障检测性能,验证了该方法的有效性.展开更多
电容式电压互感器(capacitor voltage transformer,CVT)是高压电网中广泛使用的测量设备,对CVT的内绝缘状态进行实时在线评估将有助于维护电力系统的安全稳定。但现有基于群体关联性的CVT内绝缘状态在线评估方法未考虑一次电压波动影响...电容式电压互感器(capacitor voltage transformer,CVT)是高压电网中广泛使用的测量设备,对CVT的内绝缘状态进行实时在线评估将有助于维护电力系统的安全稳定。但现有基于群体关联性的CVT内绝缘状态在线评估方法未考虑一次电压波动影响,导致评估结果可靠性不够高。针对这个问题,提出了一种计及一次电压波动影响的CVT内绝缘状态在线评估方法,该方法以CVT群体间的内在关联性和主成分分析方法对群体的输出信号进行特征提取,以排除一次电压波动的影响,得到表征CVT内绝缘异常的特征信息,再采用随机森林方法对该特征信息进行分析,实现CVT内绝缘状态的实时在线评估。实验分析表明,该方法可有效消除一次电压波动对CVT内绝缘状态在线评估的影响,实现CVT内绝缘状态的准确评估。展开更多
Developing an industrially relevant electrode with high catalytic activity,stability,and tunable composition/size for large-scale water electrolysis is a significant challenge.We have created an integrated elec-trode(...Developing an industrially relevant electrode with high catalytic activity,stability,and tunable composition/size for large-scale water electrolysis is a significant challenge.We have created an integrated elec-trode(NFM30-N)for the oxygen evolution reaction(OER)using a facile top-down approach that combines arc melting with dealloying-oxidation.Due to the dealloying-oxidation effect,the asderived porous amorphous M-O,M-OH,and M-OOH(M=Ni,Fe)nanocones cover the basic NiFeMn alloy.This integrated design enables NFM30-N to exhibit outstanding OER performance at high current densities,requiring low overpotentials of only 282 and 323 mV to achieve large current densities of 100 and 500 mA cm^(-2),respectively.It also displays a small Tafel slope of 44.1 mV dec^(-1) and remarkable stability for over 100 h at 100 and 500 mA cm^(-2).When used as an anode,a two-electrode electrolyzer cell with NFM30-N at 500 mA cm^(-2) only requires a cell voltage of 1.619 V and exhibits excellent stability,with almost no performance degradation after continuous chronopotentiometry test for each 100 h at 500 and 100 mA cm^(-2).This exceptional OER electrocatalytic performance is attributed to the integrated structure providing high electrical conductivity and stability,the presence of numerous active sites due to dealloying and the amorphous structure,and the promotion of the OER process by M-O,M-OH,and M-OOH species.This work offers a novel idea for fabricating integrated,industrially relevant electrocatalytic electrodes through traditional metallurgy combined with dealloying-oxidation.展开更多
文摘针对复杂工业生产过程具有高维度、多工况、非线性的特征以及扩散映射存在的新样本投影困难的问题,本文提出了一种基于可扩容式扩散映射和局部离群因子(expandable diffusion maps and local outlier factors, EDM-LOF)的工业过程故障检测方法.使用扩散映射方法提取训练样本的低维流形结构,构建局部投影矩阵将新样本投影至流形空间,并在流形空间中使用局部离群因子方法进行故障检测.将EDM-LOF应用于青霉素发酵过程进行故障检测,并与PCA、FD-kNN、LOF方法进行比较,结果表明EDM-LOF具有更高的故障检测性能,验证了该方法的有效性.
文摘电容式电压互感器(capacitor voltage transformer,CVT)是高压电网中广泛使用的测量设备,对CVT的内绝缘状态进行实时在线评估将有助于维护电力系统的安全稳定。但现有基于群体关联性的CVT内绝缘状态在线评估方法未考虑一次电压波动影响,导致评估结果可靠性不够高。针对这个问题,提出了一种计及一次电压波动影响的CVT内绝缘状态在线评估方法,该方法以CVT群体间的内在关联性和主成分分析方法对群体的输出信号进行特征提取,以排除一次电压波动的影响,得到表征CVT内绝缘异常的特征信息,再采用随机森林方法对该特征信息进行分析,实现CVT内绝缘状态的实时在线评估。实验分析表明,该方法可有效消除一次电压波动对CVT内绝缘状态在线评估的影响,实现CVT内绝缘状态的准确评估。
基金the National Natural Science Foundation of China(Nos.52174365,52004155,52334009 and 52130204)the National Key R&D Program of China(Nos.2023YFB3506701 and 2022YFB3706801)the Science and Technology Commission of Shanghai Municipality(No.21DZ1208900).
文摘Developing an industrially relevant electrode with high catalytic activity,stability,and tunable composition/size for large-scale water electrolysis is a significant challenge.We have created an integrated elec-trode(NFM30-N)for the oxygen evolution reaction(OER)using a facile top-down approach that combines arc melting with dealloying-oxidation.Due to the dealloying-oxidation effect,the asderived porous amorphous M-O,M-OH,and M-OOH(M=Ni,Fe)nanocones cover the basic NiFeMn alloy.This integrated design enables NFM30-N to exhibit outstanding OER performance at high current densities,requiring low overpotentials of only 282 and 323 mV to achieve large current densities of 100 and 500 mA cm^(-2),respectively.It also displays a small Tafel slope of 44.1 mV dec^(-1) and remarkable stability for over 100 h at 100 and 500 mA cm^(-2).When used as an anode,a two-electrode electrolyzer cell with NFM30-N at 500 mA cm^(-2) only requires a cell voltage of 1.619 V and exhibits excellent stability,with almost no performance degradation after continuous chronopotentiometry test for each 100 h at 500 and 100 mA cm^(-2).This exceptional OER electrocatalytic performance is attributed to the integrated structure providing high electrical conductivity and stability,the presence of numerous active sites due to dealloying and the amorphous structure,and the promotion of the OER process by M-O,M-OH,and M-OOH species.This work offers a novel idea for fabricating integrated,industrially relevant electrocatalytic electrodes through traditional metallurgy combined with dealloying-oxidation.
