Seawater electrolysis provides a sustainable pathway for large-scale hydrogen production without reliance on freshwater resources.However,its practical implementation is hindered by the short lifespan of anodes,primar...Seawater electrolysis provides a sustainable pathway for large-scale hydrogen production without reliance on freshwater resources.However,its practical implementation is hindered by the short lifespan of anodes,primarily caused by chlorine-induced corrosion in seawater.Herein,we present a self-sustaining anode protection strategy that remarkably enhances the durability of seawater electrolysis for efficient hydrogen production.This OH^(–)-trapping anode is designed by trapping OH^(–)within in-situ generated Lewis acid sites and structural vacancies formed via alkaline corrosion of amorphous NiMoSx.This design creates an anion-rich electrode interface with spontaneous accumulation and continuous replenishment of OH^(–)from the bulk electrolyte,ensuring long-lasting anode protection against corrosion through the electrostatic repulsion of chloride ions during operation.Simultaneously,it directs the anodic reaction along a stable adsorbate evolution mechanism with minimal metal leaching.Consequently,alkaline seawater electrolysis avoiding chlorine-induced corrosion achieves an exceptional lifespan exceeding 3,000 h under industrial current densities.By directly utilizing OH^(–)from the alkaline electrolyte for long-term anode protection,the operational complexity and cost of seawater electrolysis are significantly reduced,making it highly appealing for practical use.展开更多
Nitrogen injection under conditions close vicinity of the liquid-gas critical point is studied numerically. The fluid thermodynamic and transport properties vary drasti- cally and exhibit anomalies in the near-critica...Nitrogen injection under conditions close vicinity of the liquid-gas critical point is studied numerically. The fluid thermodynamic and transport properties vary drasti- cally and exhibit anomalies in the near-critical regime. These anomalies can cause distinctive effects on heat-transfer and fluid-flow characteristics. To focus on the influence of ther- modynamics on the flow field, a relatively low injection Reynolds number of 1 750 is adopted. For comparisons, a reference case with the same configuration and Reynolds number is simulated in the ideal gas regime. The model accommodates full conservation laws, real-fluid thermody- namic and transport phenomena. Results reveal that the flow features of the near-critical fluid jet are significantly differ- ent from their counterpart. The near-critical fluid jet spreads faster and mixes more efficiently with the ambient fluid along with a more rapidly development of the vortex pairing pro- cess. Detailed analysis at different streamwise locations in- cluding both the flat shear-layer region and fully developed vortex region reveals the important effect of volume dilata- tion and baroclinic torque in the near-critical fluid case. The former disturbs the shear layer and makes it more unstable. The volume dilatation and baroclinic effects strengthen the vorticity and stimulate the vortex rolling up and pairing pro- cess展开更多
为监测分布式驱动电动汽车中轮毂电机运行状态,确保整车运行安全,提出一种基于改进的多类支持向量数据描述(multi-class support vector data description,简称MCSVDD)的轮毂电机故障诊断方法。首先,针对MCSVDD算法的改进,基于近邻传播(...为监测分布式驱动电动汽车中轮毂电机运行状态,确保整车运行安全,提出一种基于改进的多类支持向量数据描述(multi-class support vector data description,简称MCSVDD)的轮毂电机故障诊断方法。首先,针对MCSVDD算法的改进,基于近邻传播(affinity propagation,简称AP)聚类算法提出了MCSVDD以“距离类内簇中心最小”的类别判断法则,并基于Weibull函数构造了Weibull核函数,用于优化数据描述模型;其次,针对轮毂电机运行状态的多维特征参数组,提出一种基于最小距离传播鉴别投影(minimum-distance propagation discriminant projection,简称MPDP)的降维法,提高了不同工况下轮毂电机故障状态的可分性;最后,定制带有典型轴承故障的轮毂电机,采集7种工况下的振动信号,验证所提出方法的有效性。结果表明:基于MPDP降维后的轮毂电机运行状态观测样本的可分性优于线性判别分析(linear discriminant analysis,简称LDA)、局部保持投影(locality preserving projection,简称LPP)及最小距离鉴别投影(minimum-distance discriminant projection,简称MDP)方法,基于Weibull核函数的MCSVDD状态识别系统的识别精度整体高于基于多项式和高斯核函数的MCSVDD系统。展开更多
基金supported by the National Natural Science Foundation of China(No.52372175)the General Program of Science and Technology of Liaoning(2024-MSBA-20)+1 种基金the Innovation and Technology Fund of Dalian(2023JJ12GX020)the Fundamental Research Funds for the Central Universities(DUT24ZD406)。
文摘Seawater electrolysis provides a sustainable pathway for large-scale hydrogen production without reliance on freshwater resources.However,its practical implementation is hindered by the short lifespan of anodes,primarily caused by chlorine-induced corrosion in seawater.Herein,we present a self-sustaining anode protection strategy that remarkably enhances the durability of seawater electrolysis for efficient hydrogen production.This OH^(–)-trapping anode is designed by trapping OH^(–)within in-situ generated Lewis acid sites and structural vacancies formed via alkaline corrosion of amorphous NiMoSx.This design creates an anion-rich electrode interface with spontaneous accumulation and continuous replenishment of OH^(–)from the bulk electrolyte,ensuring long-lasting anode protection against corrosion through the electrostatic repulsion of chloride ions during operation.Simultaneously,it directs the anodic reaction along a stable adsorbate evolution mechanism with minimal metal leaching.Consequently,alkaline seawater electrolysis avoiding chlorine-induced corrosion achieves an exceptional lifespan exceeding 3,000 h under industrial current densities.By directly utilizing OH^(–)from the alkaline electrolyte for long-term anode protection,the operational complexity and cost of seawater electrolysis are significantly reduced,making it highly appealing for practical use.
基金supported in part by the National Natural Science Foundation of China (11132010 and 11072236)
文摘Nitrogen injection under conditions close vicinity of the liquid-gas critical point is studied numerically. The fluid thermodynamic and transport properties vary drasti- cally and exhibit anomalies in the near-critical regime. These anomalies can cause distinctive effects on heat-transfer and fluid-flow characteristics. To focus on the influence of ther- modynamics on the flow field, a relatively low injection Reynolds number of 1 750 is adopted. For comparisons, a reference case with the same configuration and Reynolds number is simulated in the ideal gas regime. The model accommodates full conservation laws, real-fluid thermody- namic and transport phenomena. Results reveal that the flow features of the near-critical fluid jet are significantly differ- ent from their counterpart. The near-critical fluid jet spreads faster and mixes more efficiently with the ambient fluid along with a more rapidly development of the vortex pairing pro- cess. Detailed analysis at different streamwise locations in- cluding both the flat shear-layer region and fully developed vortex region reveals the important effect of volume dilata- tion and baroclinic torque in the near-critical fluid case. The former disturbs the shear layer and makes it more unstable. The volume dilatation and baroclinic effects strengthen the vorticity and stimulate the vortex rolling up and pairing pro- cess
