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Frontiers of Chemical Science and Engineering 2024年第3期18卷 63-73页

作者： Mengqing Shan Dongsheng Lu Jiatong Dong Shen Yan jinyu han Hua Wang Collaborative Innovation Center of Chemical Science and Engineering Key Laboratory for Green Chemical Technology of the Ministry of EducationSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin300354China

Surface engineering and Cu valence regulation are essential factors in improving the C_(2)selectivity during the electrochemical reduction of CO_(2).Herein,we present a sea urchin-like CuO/Cu_(2)O catalyst derived from rhombic dodecahedra Cu_(2)O through one-step oxidation/etching method where the mixed Cu^(+)/Cu^(0)states are formed via in situ reduction during *** combined effects of the morphology and the mixed Cu^(+)/Cu^(0)states on C–C coupling are evaluated by the Faradaic efficiency of C_(2)and the C_(2)/C1 ratio obtained in an H-cell.R-Cu^(O)/Cu_(2)O exhibited 49.5%Faradaic efficiency of C_(2)with a C_(2)/C1 ratio of 3.1 at−1.4 V *** hydrogen electrode,which are 1.5 and 3.2 times higher than those of R-Cu_(2)O,*** a flow-cell,68.0%Faradaic efficiency of C_(2)is achieved at a current density of 500 mA·cm^(−2).The formation of the mixed Cu^(+)/Cu^(0)states was confirmed by in situ Raman ***,the sea urchin-like structure provides more active sites and enables faster electron *** a result,the excellent C_(2)production on R-CuO/Cu_(2)O is primarily attributed to the synergistic effects of the sea urchin-like structure and the stable mixed Cu^(+)/Cu^(0)***,this work presents an integrated strategy for developing Cu-based electrocatalysts for C_(2)production through electrochemical CO_(2)reduction.

关键词： CO_(2)electrolysis sea urchin-like structure Cu^(+)/Cu^(0) C_(2)products

钾掺杂的锐钛矿TiO_(2)催化丙酸酮基化反应

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高校化学工程学报 2024年第3期38卷 459-467页

作者：黄胶王华韩金玉祝新利天津大学化工学院天津300072

酮基化反应是转化生物质衍生羧酸的有效途径之一。为了提高酮基化反应活性和选择性,使用等体积浸渍法制备了不同钾(K)掺杂量的TiO_(2)催化剂,并探究其催化丙酸酮基化反应性能。通过X-射线粉末衍射、透射电子显微镜和X-射线光电子能谱等... 详细信息

酮基化反应是转化生物质衍生羧酸的有效途径之一。为了提高酮基化反应活性和选择性,使用等体积浸渍法制备了不同钾(K)掺杂量的TiO_(2)催化剂,并探究其催化丙酸酮基化反应性能。通过X-射线粉末衍射、透射电子显微镜和X-射线光电子能谱等方法对催化剂的物化性质进行表征。结果表明,TiO_(2)、0.05K(掺杂K的质量分数为5%)催化剂的本征反应速率分别为549.2μmol·g^(-1)·min^(-1)、2 686.2μmol·g^(-1)·min^(-1),K的掺杂显著提高了反应活性,并且在丙酸完全转化时,0.05K催化剂的3-戊酮选择性(99.9%)高于TiO_(2)催化剂(96.2%)。根据X射线光电子能谱的表征,TiO_(2)和钾氧化物之间存在明显的相互作用,促进了表面氧空位的生成从而提高反应活性。

关键词：酮基化 TiO_(2) 钾丙酸 3-戊酮

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逻辑回归模型下激光传感器网络安全态势感知

激光杂志 2024年第2期45卷 174-180页

作者：张佳韩健韩金玉天津中德应用技术大学天津300350

为了分析不同威胁传播对激光传感器网络系统的影响,准确且全面评估系统的安全性,提出一种逻辑回归模型下激光传感器网络安全态势感知方法。将邻域粗糙集和逻辑回归模型结合,提取激光传感器网络安全态势要素。通过分析获取其不同要素的... 详细信息

为了分析不同威胁传播对激光传感器网络系统的影响,准确且全面评估系统的安全性,提出一种逻辑回归模型下激光传感器网络安全态势感知方法。将邻域粗糙集和逻辑回归模型结合,提取激光传感器网络安全态势要素。通过分析获取其不同要素的非时间序列特点,采用径向基函数(Radial Basis Function,RBF)神经网络获取网络安全态势值的非线性映射关系,构建激光传感器网络安全态势感知模型,引入混合递阶遗传算法对模型求解处理,实现网络安全态势感知。实验结果表明,所提方法获取激光传感器网络安全态势精度为96.4%,其安全态势值与实际值的误差保持在-3~3,可以获取精准的激光传感器网络安全态势变化情况,表明该方法具有一定的应用价值。

关键词：逻辑回归模型激光传感器网络安全态势感知 RBF神经网络

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa_(2)Fe_(4)As_(24F_(2)

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Chinese Physics B 2024年第7期33卷 66-70页

作者：韩金宇洪文山蔡树赵金瑜郭静周亚洲王鹏玉曹立新罗会仟李世亮吴奇孙力玲 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Center for High Pressure Science&Technology Advanced Research Beijing 100094China University of Chinese Academy of Sciences Beijing 100190China

The stability of superconductivity in superconductors is widely recognized to be determined by various factors,including charge,spin,orbit,lattice,and other related degrees of ***,we report our findings on the pressure-induced coevolution of superconductivity and Hall coefficient in KCa_(2)Fe_(4)As_(24F_(2),an iron-based superconductor possessing a hybrid crystal structure combining KFe_(2)As_(2) and *** investigation,involving high-pressure resistance,Hall effect and x-ray diffraction(XRD) measurements,allows us to observe the connection of the superconductivity and Hall coefficient with the anisotropic lattice *** find that its ambient-pressure tetragonal(T) phase presents a collapse starting at around 18 GPa,where the sign of the Hall coefficient(R_(H)) changes from positive to *** further compression,both superconducting transition temperature(T_(c)) and R_(H) exhibit a monotonous *** around 41 GPa,the superconductivity is completely suppressed(T_(c)=0),where the parameter a begins to decline again and the Hall coefficient remains nearly *** experiment results clearly demonstrate that the pressure-induced anisotropic lattice collapse plays a crucial role in tuning the interplay among multiple degrees of freedom in the superconducting system and,correspondingly,the stability of the superconductivity.

关键词： effects of pressure pnictides and chalcogenides transport properties

基于AM和CNN的多级特征融合的风力发电机轴承故障诊断方法

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太阳能学报 2024年第5期45卷 51-61页

作者：王进花韩金玉曹洁王亚丽兰州理工大学电气工程与信息工程学院兰州730050 甘肃省工业过程先进控制重点实验兰州730050 兰州理工大学电气与控制工程国家实验教学中心兰州730050 甘肃省制造信息工程研究中心兰州730050

提出一种基于注意力机制的多级特征融合卷积神经网络(A2ML2F-CNN)故障诊断方法。该方法将原始电流和振动信号作为输入,首先使用基于注意力卷积神经网络(AMCNN)模块分别进行数据信号特征提取,并进行一级特征融合连接。在此基础上,再次分... 详细信息

提出一种基于注意力机制的多级特征融合卷积神经网络(A2ML2F-CNN)故障诊断方法。该方法将原始电流和振动信号作为输入,首先使用基于注意力卷积神经网络(AMCNN)模块分别进行数据信号特征提取,并进行一级特征融合连接。在此基础上,再次分别采用注意力机制一维卷积神经网(AM1DCNN)和二维卷积神经网络(2DCNN)提取相关信息,并进行二级特征融合,以此来解决单传感器数据故障信息不足及互补特征难以提取的问题,最后采用全连接层和Softmax层进行分类,得到诊断结果。为验证所提方法的故障诊断效果,通过帕德伯恩数据集进行实验验证,并将其与CNN、LSTM、SVM等方法的诊断精度进行对比,相较于上述方法,该文方法的诊断准确率分别提高1.8、3.2和4.8个百分点,验证了所提方法的有效性。

关键词：风力机故障诊断特征融合注意力机制卷积神经网络风力发电机轴承

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矩形窄缝通道内流动沸腾的数值模拟研究

工程热物理学报 2024年第10期45卷 3151-3159页

作者：韩晋玉刘瑶赵陈儒薄涵亮清华大学核能与新能源技术研究院北京100084

窄缝通道换热技术是一体化小型模块式反应堆发展的关键技术之一。基于窄缝沸腾换热原理的换热器具有结构紧凑和换热能力强等特点。本文采用基于欧拉–欧拉法的两流体模型以及RPI壁面沸腾模型对矩形窄缝通道内流动沸腾进行模拟,本文系统... 详细信息

窄缝通道换热技术是一体化小型模块式反应堆发展的关键技术之一。基于窄缝沸腾换热原理的换热器具有结构紧凑和换热能力强等特点。本文采用基于欧拉–欧拉法的两流体模型以及RPI壁面沸腾模型对矩形窄缝通道内流动沸腾进行模拟,本文系统分析了不同封闭子模型的选择(包括汽泡脱离直径dw和汽化核心密度Nw)对流动沸腾中汽泡参数、传热及流场预测的影响。基于模拟结果下不同封闭模型的选择,提出了适用于矩形窄缝通道内流动沸腾且工况适应范围较广的汽泡参数子模型的优化组合。研究结论可为反应堆换热元件和紧凑式换热器设计计算提供参考依据。

关键词：矩形窄缝通道流动沸腾 CFD 壁面沸腾模型

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汽泡边界层模型在矩形管道下的适用性分析

原子能科学技术 2024年第4期58卷 751-760页

作者：何雯赵陈儒韩晋玉薄涵亮清华大学核能与新能源技术研究院北京100084

过冷流动沸腾中的流动和传热特性对反应堆的安全运行和经济性都具有重要意义。汽泡边界层模型是预测流动沸腾的一种新理论模型,它将流场沿径向划分为主流和汽泡边界层两个区域,能同时获得两个区域多个两相参数的变化规律,为空泡份额的... 详细信息

过冷流动沸腾中的流动和传热特性对反应堆的安全运行和经济性都具有重要意义。汽泡边界层模型是预测流动沸腾的一种新理论模型,它将流场沿径向划分为主流和汽泡边界层两个区域,能同时获得两个区域多个两相参数的变化规律,为空泡份额的预测提供了一种新的方法。然而,过冷沸腾段汽泡边界层模型目前仅在常规圆管中开展了验证,当管道类型和尺寸发生变化后,模型的准确度还有待进一步分析。基于此,本文将汽泡边界层模型进一步推广到长宽比较大的矩形管道中。为验证模型的准确性,将模型获得的空泡份额与现有实验数据进行对比,并同时与现有空泡份额预测模型进行了对比。结果显示,汽泡边界层模型不仅较现有模型的准确度更高,还能同时应用于矩形常规管道和窄缝通道,受管道结构和尺寸的影响较小。模型还描述了矩形窄缝通道内空泡份额、压力、流速、温度、滑速比等的变化情况,这些结果能为反应堆矩形燃料元件内的热工物理耦合分析提供基础数据。

关键词：过冷流动沸腾汽泡边界层模型矩形管道空泡份额两相参数

精密平台磁敏智能隔振系统自适应PI控制研究

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振动与冲击 2024年第8期43卷 232-237,302页

作者：钟灿黄振李旺浮洁韩锦聿余淼綦松重庆大学光电工程学院光电技术及系统教育部重点实验室重庆400044

为抑制精密平台存在的时变振动,提出一种基于磁流变弹性体(magneto rheological elastomer,MRE)半主动自适应比例积分(proportional integral,PI)控制方法。首先针对MRE隔振系统,建立其动力学模型,并根据MRE变刚度隔振原理,推导半主动... 详细信息

为抑制精密平台存在的时变振动,提出一种基于磁流变弹性体(magneto rheological elastomer,MRE)半主动自适应比例积分(proportional integral,PI)控制方法。首先针对MRE隔振系统,建立其动力学模型,并根据MRE变刚度隔振原理,推导半主动控制条件;其次以响应加速度和目标加速度偏差作为PI控制器输入,通过遗传算法获得不同频率、幅值激励下的最优PI控制参数,并基于被动参考模型获得频率幅值依赖自适应律。该方法无须通过复杂的傅里叶变换辨识频率,实时性高;最后通过仿真和试验验证了所设计控制器的有效性;结果表明,与传统PI控制器相比,自适应PI控制器对40~50 Hz、1.0~3.0 m/s^(2)时变振动具有更大的抑制。

关键词：磁流变弹性体隔振器精密加工平台自适应PI控制时变激励

Evolution of Superconducting-Transition Temperature with Superfluid Density and Conductivity in Pressurized Cuprate Superconductors

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Chinese Physics Letters 2024年第4期41卷 110-117页

作者：赵金瑜蔡树陈逸雯顾根大闫宏涛郭静韩金宇王鹏玉周亚洲李延春李晓东任治安吴奇周兴江丁阳向涛毛河光孙力玲 Institute of Physics Chinese Academy of SciencesBeijing 100190China Center for High Pressure Science&Technology Advanced Research Beijing 100094China Condensed Matter Physics&Materials Science Department Brookhaven National LaboratoryNY 11973-5000USA University of Chinese Academy of Sciences Beijing 100190China Institute of High Energy Physics Chinese Academy of ScienceBeijing 100049China Beijing Academy of Quantum Information Sciences Beijing 100193China

What factors fundamentally determine the value of superconducting transition temperature Tc in high temperature superconductors has been the subject of intense *** the establishment of an empirical law known as Homes'law,there is a growing consensus in the community that the Tc value of the cuprate superconductors is closely linked to the superfluid density(ρ_(s))of its ground state and the conductivity(σ)of its normal ***,all the data supporting this empirical law(ρ_(s)=AσT_(c))have been obtained from the ambientpressure *** this study,we present the first high-pressure results about the connection of the quantities of ρ_(s) and σ with T_(c),through the studies on the Bi_(1.74)Pb_(0.38)Sr_(1.88)CuO_(6+δ)and Bi_(2)Sr_(2)CaCu_(2)O_(8+δ),in which the value of their high-pressure resistivity(ρ=1/σ)is achieved by adopting our newly established method,while the quantity ofρs is extracted using Homes'*** highlight that the Tc values are strongly linked to the joint response factors of magnetic field and electric field,i.e.,ρ_(s) and σ,respectively,implying that the physics determining T_(c) is governed by the intrinsic electromagnetic fields of the system.

关键词： superconductors Transition Conductivity

Electrodeposited porous Pb electrode with improved electrocatalytic performance for the electroreduction of CO2 to formic acid

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Frontiers of Chemical Science and Engineering 2015年第1期9卷 57-63页

作者： Jing WANG Hua WANG Zhenzhen han jinyu han Tianjin Co-innovation Center on Chemical Science & Engineering Key Laboratory for Green Chemical Technology of State Education Ministry School of Chemical Engineering & Technology Tianjin University Tianjin 300072 China

A porous Pb foam was fabricated electroche- mically at a copper substrate and then used as the cathode for the electroreduction of COE. The surface morphology and composition of the porous Pb electrode was characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and selected area electron diffraction. The honeycomb-like porous structure was composed of needle-like Pb deposits. Cyclic voltammetry studies demonstrated that the porous Pb electrode had better electrocatalytic performance for the formation of formic acid from CO2 compared with a Pb plate electrode. The increase in current density was due to the large surface area of the porous Pb electrode, which provides more active sites on the electrode surface. The improved formic acid selectivity was due to the morphol- ogy of the roughened surface, which contains significantly more low-coordination sites which are more active for CO2 reduction. The highest current efficiency for formic acid was 96.8% at - 1.7 V versus saturated calomel electrode at 5℃. This porous Pb electrode with good catalytic abilities represents a new 3D porous material with applications for the electroreduction of CO2.

关键词： electrodeposited porous Pb carbon dioxide,electroreduction formic acid