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Improved dynamic regret of distributed online multiple Frank-Wolfe convex optimization

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Science China(Information Sciences) 2024年第11期67卷 164-179页

作者： wentao zhang Yang SHI Baoyong zhang Deming YUAN School of Automation Nanjing University of Science and Technology Department of Mechanical Engineering University of Victoria

In this paper, we explore a distributed online convex optimization problem over a time-varying multi-agent network. The network aims to minimize a global loss function through local computation and communication with neighboring agents. To effectively handle the optimization problem which involves highdimensional and structural constraint sets, we develop a distributed online multiple Frank-Wolfe algorithm that circumvents the expensive computational cost associated with projection operations. The dynamic regret bounds are established as O(T1-γ+ HT) with the linear oracle number O(T1+γ), which depends on the horizon（total iteration number） T, the function variation HT, and the tuning parameter 0 < γ < *** particular, when the prior knowledge of HTand T is available, the bound can be enhanced to O（1 +HT）. Moreover, we explore the significant advantages provided by the multiple iteration technique and reveal a trade-off between dynamic regret bound, computational cost, and communication cost. Finally,the performance of our algorithm is validated and compared through the distributed online ridge regression problems with two constraint sets.

关键词： distributed online convex optimization multiple iterations Frank-Wolfe algorithm dynamic regret gradient tracking method

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Visible light-driven oxidation of non-native substrate by laccase attached on Ru-based metal-organic frameworks

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Journal of Environmental Sciences 2024年第3期137卷 741-753页

作者： Wenguang Huang wentao zhang Guantongyi Chen Yun Chen Jun Ma Dawei Huang Qinzheng Zhaoc Bingdang Wu State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment South China Institute of Environmental SciencesMinistry of Ecology and Environment of PRCGuangzhou 510655China Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215002China Key Laboratory of Suzhou Sponge City Technology Suzhou 215002China

Light-induced electron transfer can broaden the substrate range of ***,the efficiency of photo-enzyme coupling is limited by the poor combination of photosensitizer or photocatalyst with ***,we prepared the nano-photocatalyst MIL-125-NH_(2)@Ru(bpy)by in site embedding ruthenium pyridine-diimine complex[Ru(bpy)_(3)^(2+)into metal organic frameworks MIL-125-NH_(2)and associated it with multicopper oxidase(MCO)*** to[Ru(bpy)_(3)]^(2+),the coupling efficiency of MIL-125-NH_(2)@Ru(bpy)_(3)for enzymatic oxygen reduction increased by 35.7%.A series of characterizations confirmed that the amino group of laccase formed chemical bonds with the surface defects or hydrophobic groups of MIL-125-NH_(2)@Ru(bpy)_(3).Consequently,the tight binding accelerated the quenching process and electron transfer between laccase and the immobilized ruthenium pyridine-diimine *** work would open an avenue for the synthesis of MOFs photocatalyst towards photo-enzyme coupling.

关键词： Laccase Light-driven biocatalysis Ruthenium photocatalyst Metal-organic frameworks Enzyme immobilization

Multiscale engineering of molecular electrocatalysts for the rapid hydrogen evolution reaction

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Nano Research 2024年第7期17卷 6026-6031页

作者： Huan Li Zhan Jiang Yubo Yuan Yirong Tang Jie Zao wentao zhang Peiyi Han Xun zhang Bulin Chen Yongye Liang Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China South China Institute of Environmental Sciences Guangzhou 510655China

Molecular electrocatalysts have demonstrated potential for the hydrogen evolution reaction(HER)due to their well-defined structures and high intrinsic *** rapid production of hydrogen requires molecular electrocatalysts to operate at high current densities,which still presents a *** this work,we demonstrate that molecularly dispersed electrocatalysts of cobalt phthalocyanine anchored on carbon nanotubes(CoPc MDEs)are superior candidates due to the efficient charge transport between the substrate and the active *** intrinsic activity can be enhanced by introducing functional groups on *** facilitate mass transport,di(ethylene glycol)substituted CoPc molecules are further anchored on a threedimensional self-supported electrode(CoPc-DEG MDE@CC),enabling continuous operation for 25 h at−1000 mA/cm^(2)in 1.0 M *** study demonstrates the potential of molecular electrocatalysts for HER and emphasizes the importance of adjusting intrinsic activity,and charge and mass transport capacity for practical molecular electrocatalysts.

关键词： hydrogen evolution reaction cobalt phthalocyanine intrinsic activity mass transport

Design principle of single-atom catalysts for sulfur reduction reaction—interplay between coordination patterns and transition metals

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Science China Materials 2024年第10期67卷 3215-3224页

作者： wentao zhang Gaoshang zhang Zhaotian Xie Xinming zhang Jiabin Ma Ziyao Gao Kuang Yu Lele Peng Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The polysulfide shuttling effect is the primary bottleneck restricting the industrial application of Li-S batteries,and the electrocatalytic sulfur reduction reaction(SRR)has emerged as an effective ***-based singleatom catalysts(SACs),which promotes SRR,show great potential in inhibiting the shuttling effect of ***,the optimization and rational design of such catalysts requires a deep understanding to the fundamental SRR mechanism and remains highly *** this work,we construct a comprehensive database of carbon-based SACs,covering different coordination patterns,heteroatoms,and transition *** SRR activities are determined using density functional theory calculations,revealing a synergistic effect between the p orbital of the heteroatom and the d orbital of the transition *** interplay underscores the critical importance of the coordination environment for SRR under the ortho-P_(2)C_(2)*** of the transition metal type,the ortho-P_(2)C_(2)coordination pattern significantly enhances the SRR performance of SACs,surpassing the widely reported N_(3)C_(1)and N_(4)coordinated graphene-based ***,heteroatoms with ortho-P_(2)C_(2)may exhibit SRR *** a word,by using this comprehensive dataset and data-driven framework,we propose a promising novel class of coordination structure(ortho-P_(2)C_(2)structure)and neglected design principle.

关键词： single-atom catalysts ortho-P doped structure abinitio calculations machine learning sulfur reduction reaction

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基于自适应整形正则化的AVAz反演

地球物理学报 2024年第6期67卷 2429-2438页

作者：薛姣顾汉明贺梅张文涛中国地质大学(武汉)地球物理与空间信息学院武汉430074 地球内部多尺度成像湖北省重点实验室武汉430074 电子科技大学长三角研究院(湖州) 湖州313001 地大汇能(北京)科技有限公司北京100085

高角度裂缝的存在导致地下介质呈现方位各向异性,具有水平对称轴的横向各向同性介质中反射系数随方位角的变化可以近似表示为傅里叶级数的形式.傅里叶系数的大小取决于背景介质和裂缝参数,傅里叶系数的相位角取决于裂缝对称轴方向.常规... 详细信息

高角度裂缝的存在导致地下介质呈现方位各向异性,具有水平对称轴的横向各向同性介质中反射系数随方位角的变化可以近似表示为傅里叶级数的形式.傅里叶系数的大小取决于背景介质和裂缝参数,傅里叶系数的相位角取决于裂缝对称轴方向.常规傅里叶级数分析利用逐个时间采样点的方位地震数据求和计算傅里叶系数,计算结果易受噪声影响.为了提高傅里叶系数估计的抗噪性和稳定性,将常规傅里叶级数分析与AVAz(振幅随方位角变化)反演方法相结合,提出一种基于整形正则化的AVAz二阶傅里叶系数反演方法.常规整形正则化约束中的整形算子形态固定,提出一种基于方位各向异性强度的自适应整形算子,利用基于常规傅里叶级数分析的二阶傅里叶系数初步估计结果计算阻尼因子,结合一阶差分矩阵构建自适应整形算子,达到在反演中自适应地调整整形算子形态的目的.理论测试表明,基于自适应整形正则化的AVAz反演方法具有较强的抗噪性,能够有效提高二阶傅里叶系数反演的稳定性.实际叠前地震数据应用结果显示裂缝预测结果与测井资料相吻合,证明了基于自适应整形正则化AVAz反演进行裂缝预测的有效性.

关键词：裂缝储层 AVAz反演傅里叶系数整形正则化自适应整形算子

SLM制备Ti6Al4V合金表层组织的均质化及腐蚀行为研究

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中南大学学报（自然科学版） 2024年第8期55卷 2991-3001页

作者：郑志军张文韬华南理工大学机械与汽车工程学院广东广州510641

采用激光选区熔化(SLM)增材制造工艺制备致密度为97.5%的Ti6Al4V合金,并利用高能喷丸与退火处理复合工艺对垂直建造方向的XOY面及平行建造方向的XOZ面进行均质化处理,然后对原始打印件、喷丸处理以及喷丸+退火处理的3种状态的试样进行... 详细信息

采用激光选区熔化(SLM)增材制造工艺制备致密度为97.5%的Ti6Al4V合金,并利用高能喷丸与退火处理复合工艺对垂直建造方向的XOY面及平行建造方向的XOZ面进行均质化处理,然后对原始打印件、喷丸处理以及喷丸+退火处理的3种状态的试样进行电化学性能测试。研究结果表明:经喷丸处理后,原始打印件XOY面和XOZ面的组织趋于均质化,同时组织明显细化;喷丸既不改变衍射峰的位置,也不产生新的衍射峰,但可使衍射峰宽化;对于喷丸后经不同温度退火处理的样品,随退火温度的升高,XOY面和XOZ面的晶粒逐渐长大,在780℃退火后,二者均可获得α+β双相组织。对于原始打印件,XOY面和XOZ面的电化学腐蚀行为存在明显的差异,其中,XOY面的腐蚀倾向更小,耐蚀性能更优。经喷丸+退火处理后,这种差异明显减小,同时耐蚀性能进一步提高,经综合考虑可得喷丸+780℃退火为最佳工艺。

关键词：激光选区熔化 Ti6Al4V合金喷丸组织各向异性

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核心素养导向的高中数学建模课程构建与实施

中国教育学刊 2024年第2期 1-8页

作者：张文涛深圳中学广东深圳518001

在新一轮高中数学课程改革中,数学建模成为学生必修内容。如何在核心素养的目标导向下构建数学建模课程并有效开展实践,是当前课程设计者和一线教师面临的重点与难点任务。通过构建发展核心素养的数学建模课程体系、组建“知识建构—互... 详细信息

在新一轮高中数学课程改革中,数学建模成为学生必修内容。如何在核心素养的目标导向下构建数学建模课程并有效开展实践,是当前课程设计者和一线教师面临的重点与难点任务。通过构建发展核心素养的数学建模课程体系、组建“知识建构—互动研讨—课题研究”三位一体课程实践模式、搭建课题式研究和开放式探究学习框架、创建研究过程与项目成果并重的“四维融合”评价体系等四个方面,解决数学建模教学中的诸多问题,为课程设计和一线教学提供参考。

关键词：数学建模综合实践核心素养课程构建高中数学

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微地形风场下架空输电导线风致振动特性分析

中南大学学报（自然科学版） 2024年第4期55卷 1567-1580页

作者：赵珊鹏马爱彪张友鹏张文韬王锋张海喜兰州交通大学自动化与电气工程学院甘肃兰州730070 中国能源建设集团甘肃省电力设计院有限公司甘肃兰州730050

为研究微地形下架空输电导线风振特性以完善输电线路抗风设计,采用计算流体动力学方法(CFD)模拟得出微地形下不同线路处风速及攻角变化规律,并推导输电导线相对运动时的脉动风荷载。建立跨越微地形的三跨输电导线有限元模型,利用谐波合... 详细信息

为研究微地形下架空输电导线风振特性以完善输电线路抗风设计,采用计算流体动力学方法(CFD)模拟得出微地形下不同线路处风速及攻角变化规律,并推导输电导线相对运动时的脉动风荷载。建立跨越微地形的三跨输电导线有限元模型,利用谐波合成法(WAWS)模拟时间和空间相关的线路脉动风场,对导线施加风荷载,分析微地形下输电导线风振响应。研究结果表明:在微地形下,来流经谷口与山顶时加速明显,水平风速最大加速比达到1.42,坡前垂向风速不可忽略;相较平地风场,跨越山谷、山顶线路第二跨导线的跨中水平位移幅值分别增大58.27%和56.39%,导线水平张力和绝缘子风偏角度大幅增加,导线覆冰舞动可能导致空气间隙不足发生放电,在抗风设计时须增大设计风速;坡前线路风振位移减小,可适当减小安全裕度。研究结果可为复杂山地地形下输电导线抗风设计提供参考。

关键词：微地形输电线路气动力参数数值模拟风致振动

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何首乌致肝内胆管消失综合征1例

中华肝脏病杂志 2024年第3期32卷 248-250页

作者：关善斌张文涛郭卉天津中医药大学第一附属医院肝胆科、国家中医针灸临床医学研究中心天津300381

药物相关胆管消失综合征是药物引起的以肝内胆管减少为病理学特征,以胆汁淤积为主要临床特点的综合征,临床相对少见。现报道1例何首乌相关胆管消失综合征的病例资料,以供临床医师参考。

关键词：何首乌胆管消失综合征药物性肝损伤