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Nano Research 2024年第5期17卷 3879-3887页

作者： Yuting Chen Tian Meng Zhicai Xing Yueying Yan yang yang Bohan Yao Dewen Wang Xiurong yang State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Developing efficient pH-universal hydrogen evolution reaction(HER)catalysts is critical in the field of water electrolysis,however,which is severely hampered by the sluggish kinetics in alkaline ***,a ruthenium(Ru)incorporation induced vacancy engineering strategy is firstly proposed to precisely construct oxygen vacancy(V_(O))-riched cobalt-ruthenium metaphosphate(CRPO)for high-efficiency pH-universal *** V_(O) modifies the electronic structure,improves the superficial hydrophilic and gas spillover capacity,it also reduces the coordination number of Ru atoms and regulates the coordination *** calculations indicate that Ru tends to adsorb H_(2)O and H^(*),whereas V_(O) tends to adsorb OH^(-),which greatly promotes the H_(2)O adsorption and the dissociation of HO-H ***,CRPO-2 exhibits remarkable HER performance,the mass activity is about 18.34,21.73,and 38.07 times higher than that of Pt/C in acidic,neutral,and alkaline media,respectively,at the same time maintain excellent *** findings may pave a new avenue for the rational design of electrocatalysts toward pH-universal water electrolysis.

关键词： cobalt metaphosphate pH-universal hydrogen evolution reaction(HER) vacancy engineering low-coordination atoms oxygen vacancy

Engineering Cu_(2)O/Cu/N-C interface to induce directional migration of charge for driving photocatalytic homo-coupling of terminal alkynes

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Nano Research 2024年第8期17卷 6895-6902页

作者： Xiaoqin Yan Tianyi Xu Wenwen Zhan yang yang yang Yu Jianjian Yi Xiaoxiao He Lei yang Jianwei Zhao Liming Sun Xiguang Han Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials Department of ChemistrySchool of Chemistry&Materials ScienceJiangsu Normal UniversityXuzhou 221116China State Key Laboratory of Precision Spectroscopy East China Normal UniversityShanghai 200241China College of Environmental Science and Engineering Yangzhou UniversityYangzhou 225009China Shenzhen HUASUAN Technology Co. LtdShenzhen 518055China

The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to form key intermediates with reactant *** present study successfully synthesized a crusiform-like mesoporous structure of nitrogen-doped carbon-coated Cu_(2)O/Cu(Cu_(2)O/Cu/N-C)with a Cu_(2)O/dual electron acceptor interface using etched HKUST-1 as the precursor.A series of theoretical and experimental studies have demonstrated that the Cu_(2)O/Cu/N-C interface in the photocatalytic homo-coupling of terminal alkynes not only effectively enhances the separation of photogenerated electron−hole pairs,but also facilitates the formation of the key intermediate[Cu_(2)O/Cu/N-C]-phenylacetylide and promotes the rearrangement of its internal *** a result,the homo-coupling reaction can be effectively *** primary reason for the functional role of Cu_(2)O/Cu/N-C interface lies in the downward bending of energy band from Cu_(2)O to N-doped C layers,induced by the different work functions of Cu_(2)O,Cu and N-doped C ***,Cu_(2)O/Cu/N-C photocatalysts demonstrate exceptional photocatalytic activity in the homo-coupling reaction of terminal alkynes under blue-light irradiation and air *** present study presents a novel research methodology for the development of highly efficient visible light catalysts to facilitate organic reactions in future applications.

关键词： photocatalysis homo-coupling of terminal alkynes directional migration of charges heterojunction interface Cu_(2)O carbon coated

A lightweight and high compressive resistance thermal insulation material with dual-network structure

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Nano Research 2024年第5期17卷 4279-4287页

作者： Mengmeng yang Zhaofeng Chen yang Ding Wu Qiong Tianlong Liu Manna Li Lixia yang Sheng Cui School of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech UniversityNanjing 211816China

Ceramic fibrous aerogels are highly desirable for thermal management materials due to their high porosity,excellent elasticity,thermal conductivity,and good thermal ***,the fabrication of nanofibrous aerogel with super-elasticity and good shape retention at the same time has remained *** meet the requirements,a novel anisotropy nanofibrous-granular aerogel with a quasi-layered multi-arch-like and hierarchical-cellular structure is designed and prepared by vacuum-filtration-assisted freeze-drying and *** quasi-layered multi-arch and flexible nanofibers endowed the aerogels with excellent mechanical robustness(ultimate stress up to 60 kPa with strain 60%)and super-elasticity with recoverable compression strain up to 60%.The introduced SiO_(2) aerogel nanoparticles and nanofibers are assembled into an arch-like structure and become the connection point of adjacent nanofibers,which endows low thermal conductivity(0.024 mW/(m·K))of composite *** novel strategy provides a fresh perspective for the preparation of nanofibrous aerogel with robust mechanical in thermal insulation and other fields.

关键词： nanofibrous aerogel dual-network structure thermal insulation nanofibrous-granular composite aerogels strong mechanical

Post lithium-sulfur battery era:challenges and opportunities towards practical application

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Science China Chemistry 2024年第1期67卷 106-121页

作者： Jiahang Chen yang Zhang Jun yang Yanna Nuli Jiulin Wang State Key Laboratory of Chemistry and Utilization of Carbon-Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China Department of Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Lithium-sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system owing to the high theoretical energy density and natural abundance of *** fundamental researches have pushed the flourishing development on electrochemical behaviors in recent 20 *** is time to evolve into post-Li-S battery era with the pursuit towards practical *** the landmark leap,numerous new challenges appear under harsh conditions,such as high sulfur loading,low cathode density,lean electrolyte and limited lithium ***,we summarize the considerable parameters of pouch Li-S cells and review the pioneering studies focused on the cathode structure,conversion kinetics,electrode interphase and battery *** interwoven relationship of these key points is concluded and discussed,which provides guidance to future researches aiming to safe and long-lifespan Li-S batteries with high energy density.

关键词： lithium-sulfur batteries practical application harsh conditions energy density pouch cells

Solid-conversion synthesis of three-dimensionally ordered mesoporous ZSM-5 catalysts for the methanol-to-propylene reaction

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Frontiers of Chemical Science and Engineering 2024年第8期18卷 111-122页

作者： Weilong Chun Chenbiao yang Xu Wang Xin yang Huiyong Chen School of Chemical Engineering Northwest UniversityXi’an 710069China International Science&Technology Cooperation Base for Clean Utilization of Hydrocarbon Resources Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei EnergyCollaborative Innovation Center for Development of Energy and Chemical Industry in Northern ShaanxiNorthwest UniversityXi’an 710069China

A facile synthesis of hierarchical ZSM-5 with the three-dimensionally ordered mesoporosity(3DOm ZSM-5)was achieved by solid conversion(SC)of SiO_(2)colloidal crystals to high-crystalline *** products of 3DZ5_S/C and 3DZ5_S,which were severally transformed from the carbon-padded SiO_(2)colloidal crystals and the initial SiO_(2)colloidal crystals,exhibited not only a similar ordered structure and acidity but also higher crystallinity and more balanced meso-/micropore combination in comparison with 3DZ5_C obtained by the conventional confined space crystallization *** three synthesized 3DZ5 catalysts showed improved methanol-to-propylene performance than the commercially microporous ZSM-5(CZ5),embodied in five times longer lifetime,higher propylene selectivity and S_(propylene)/S_(ethylene) ratio(P/E),and superior coke toleration with lower formation rate of coke(R_(coke)).Moreover,the 3DZ5_S catalyst in situ converted from SiO_(2)colloidal crystals presented the highest selectivities of propylene(42.51%)and light olefins(74.6%)among all three 3DZ5 *** high efficiency in synthesis and in situ utilization of SiO_(2)colloidal crystals demonstrate the proposed SC strategy to be more efficiently and eco-friendly for the high-yield production of not only 3DOm ZSM-5 but also other types of hierarchical zeolites.

关键词： hierarchical zeolite three-dimensionally ordered mesoporosity ZSM-5 solid conversion methanol-to-propylene

Mitigate noisy data for smart IoT via GAN based machine unlearning

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Science China(Information Sciences) 2024年第3期67卷 62-78页

作者： Zhuo MA Yilong yang yang LIU Xinjing LIU Jianfeng MA School of Cyber Engineering Xidian University State Key Laboratory of Integrated Services Networks (ISN)

With the development of IoT applications, machine learning dramatically improves the utility of variable IoT systems such as autonomous driving. Although the pretrain-finetune framework can cope well with data heterogeneity in complex IoT scenarios, the data collected by sensors often contain unexpected noisy data, e.g., out-of-distribution(OOD) data, which leads to the reduced performance of fine-tuned models. To resolve the problem, this paper proposes Mu GAN, a method that can mitigate the side-effect of OOD data via the generative adversarial network(GAN)-based machine unlearning. Mu GAN follows a straightforward but effective idea to mitigate the performance loss caused by OOD data, i.e., “flashbacking” the model to the condition where OOD data are excluded from model training. To achieve the goal, we design an adversarial game, where a discriminator is trained to identify whether a sample belongs to the training set by observing the confidence score. Meanwhile, a generator(i.e., the target model) is updated to fool the discriminator into believing that the OOD data are not included in the training set but others do. The experimental results show that benefiting from the high unlearning rate(more than 90%) and retention rate(99%), Mu GAN succeeds in lowering the model performance degradation caused by OOD data from 5.88% to 0.8%.

关键词： machine unlearning generative adversarial network out of distribution data Internet of Thing neural network

Asymptotics for the joint tail probability of bidimensional randomly weighted sums with applications to insurance

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Science China Mathematics 2024年第1期67卷 163-186页

作者： yang yang Shaoying Chen Kam Chuen Yuen School of Statistics and Data Science Nanjing Audit UniversityNanjing 211815China Department of Statistics and Actuarial Science The University of Hong KongHong Kong 999077China

This paper studies the joint tail behavior of two randomly weighted sums∑_(i=1)^(m)Θ_(i)X_(i)and∑_(j=1)^(n)θ_(j)Y_(j)for some m,n∈N∪{∞},in which the primary random variables{X_(i);i∈N}and{Y_(i);i∈N},respectively,are real-valued,dependent and heavy-tailed,while the random weights{Θi,θi;i∈N}are nonnegative and arbitrarily dependent,but the three sequences{X_(i);i∈N},{Y_(i);i∈N}and{Θ_(i),θ_(i);i∈N}are mutually *** two types of weak dependence assumptions on the heavy-tailed primary random variables and some mild moment conditions on the random weights,we establish some(uniformly)asymptotic formulas for the joint tail probability of the two randomly weighted sums,expressing the insensitivity with respect to the underlying weak dependence *** applications,we consider both discrete-time and continuous-time insurance risk models,and obtain some asymptotic results for ruin probabilities.

关键词： asymptotic joint tail behavior randomly weighted sum heavy-tailed distribution dependence insurance risk model

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施工监控状态下病害闸拱桥的拆除

武汉工程大学学报 2019年第4期41卷 375-379页

作者：陈旭勇周扬杨宏印武汉工程大学土木工程与建筑学院

闸桥作为一种具有特定功能的桥梁,兼备交通通行与蓄水泄洪功能。某23孔实腹式圬工闸拱桥通过桥梁检测及专家评审,确定利用桥墩、桥台、基础等下部结构,拆除主拱圈、填料、桥面系等上部结构。为保证桥梁安全,提出2种拱上填料挖除方案进... 详细信息

闸桥作为一种具有特定功能的桥梁,兼备交通通行与蓄水泄洪功能。某23孔实腹式圬工闸拱桥通过桥梁检测及专家评审,确定利用桥墩、桥台、基础等下部结构,拆除主拱圈、填料、桥面系等上部结构。为保证桥梁安全,提出2种拱上填料挖除方案进行比选,通过计算分析,确定扰动较小的方案。采用建桥逆工序拆除法逐步卸除上部结构,并结合施工监控,形成拆除过程预警机制。最后,施工监控结果符合预期理论分析,整个拆除过程安全有序。

关键词：连拱拱桥闸桥拆除施工监控

A novel predictive braking energy recovery strategy for electric vehicles considering motor thermal protection

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Science China(Technological Sciences) 2024年第4期67卷 1253-1269页

作者： yang Chao SUN TongLin yang LiuQuan ZHANG YuHang WANG WeiDa School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100084China

Braking energy recovery(BER)aims to recover the vehicle's kinetic energy by coordinating the motor and mechanical braking torque to extend the driving range of the electric vehicle(EV).To achieve this goal,the motor/generator mode requires frequent switching and prolonged operation during *** this case,the motor temperature will unavoidably rise,potentially triggering motor thermal protection(MTP).Activating MTP increases the risk of motor component failure,and the EV typically disables the BER ***,maximizing BER while reducing the risk of motor overheating is a challenging *** address this issue,this article proposes a predictive BER strategy with MTP using the non-smooth Pontryagin Minimum Principle(NSPMP)for ***,a Markov long short-term memory(MLSTM)model is designed to obtain future velocity ***,the BER problem with MTP in the studied EV is embedded in a model predictive control(MPC)***,under the MPC framework,the NSPMP strategy is proposed to resolve the problem of ***,the performance of the proposed strategy is verified through simulation and a hardware-in-loop *** results show that in two real-world driving cycles,compared to the rule-based strategy,the proposed strategy reduced power consumption by 1.24%and0.96%,respectively,and effectively limited motor ***,under global cycle conditions,this strategy demonstrated better MTP control performance compared to other benchmark strategies.

关键词： electric vehicle braking energy recovery strategy motor thermal protection non-smooth PMP

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考虑瞬时脱离的列车作用下桥梁振动分析

重庆交通大学学报（自然科学版） 2014年第2期33卷 21-25页

作者：杨宏印张海龙陈志军黄雯华中科技大学土木工程与力学学院湖北武汉430074 中铁大桥局集团武汉桥梁科学研究院有限公司湖北武汉430034

采用非线性Hertz接触理论,并将其线性化,推导了考虑车轮瞬时脱离的车-桥耦合分析单元,解决了传统分析中"车轮密贴"假设的不足;应用形成矩阵的"对号入座"法则建立了耦合系统动力方程,并给出了其组装和求解思路;编制了相应计算程序,对现... 详细信息

采用非线性Hertz接触理论,并将其线性化,推导了考虑车轮瞬时脱离的车-桥耦合分析单元,解决了传统分析中"车轮密贴"假设的不足;应用形成矩阵的"对号入座"法则建立了耦合系统动力方程,并给出了其组装和求解思路;编制了相应计算程序,对现有铁路桥梁进行了分析。结果表明:车桥共振时,桥梁动力响应会显著增大,而移动力模型结果更偏于安全,脉冲型不平顺会激起强烈的高频振动,使桥梁加速度响应显著增加;未发生脱离时,考虑和不考虑脱离模型所得结果一样,而发生脱离时,后者结果将不准确,而前者准确模拟出了脱离现象;应采用考虑车轮脱离的模型进行车-桥耦合振动分析,同时应重视线路养护维修和桥梁变形控制。

关键词：桥梁工程车-桥耦合单元车轮瞬时脱离 Hertz接触车-桥共振动力分析