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Preparation of Flower-like Copper Foam Supported Co_(3)O_(4) Electrocatalyst and Its Hydrogen Evolution Performance

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 327-331页

作者：李兆 CHENG Julong WANG yanan WU Kunyao cao Jing School of Materials Engineering Xi’an Aeronautical InstituteXian 710077China

Flower-like copper foam Co_(3)O_(4) catalysts(Co_(3)O_(4)/CF) were prepared by hydrothermal method.The crystalline structure and microscopic morphology of the prepared samples were characterized by using X-ray diffractometer(XRD) and scanning electron microscope(SEM),and the electrochemical properties were investigated by an electrochemical workstation.The experimental results show that the Co_(3)O_(4) catalysts are successfully prepared on the foamed copper support by hydrothermal method,and the material’s morphology is mainly flower cluster.When the current density is 10 mA·cm^(-2),the overpotential value of the Co_(3)O_(4)/CF catalyst is 141 mV,lower than that of blank support.The electrochemical impedance(EIS) spectrum shows that the R_(ct )value of the Co_(3)O_(4)/CF catalyst decreases,and the Coulomb curves of double-layer show that the electrochemically active area of the Co_(3)O_(4)/CF catalyst efficiently increases compared with that of the blank support.Therefore,the as-obtained Co_(3)O_(4)/CF catalyst exhibits a good hydrogen evolution rate,showing great applicability potential in the catalytic electrolysis of water for hydrogen production.

关键词： Co_(3)O_(4)/CF composite structure electrocatalysis hydrogen evolution reaction

Constructing Al@C-Sn pellet anode without passivation layer for lithium-ion battery

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 552-561页

作者： Kangzhe cao Sitian Wang yanan He Jiahui Ma Ziwei Yue Huiqiao Liu College of Chemistry and Chemical Engineering Xinyang Normal UniversityXinyang 464000China Xinyang Key Laboratory of Low-Carbon Energy Materials Xinyang 464000China Henan Province Key Laboratory of Utilization of Non-Metallic Mineral in the South of Henan Xinyang 464000China

Al is considered as a promising lithium-ion battery(LIBs)anode materials owing to its high theoretical capacity and appropri-ate lithation/de-lithation potential.Unfortunately,its inevitable volume expansion causes the electrode structure instability,leading to poor cyclic stability.What’s worse,the natural Al2O3 layer on commercial Al pellets is always existed as a robust insulating barrier for elec-trons,which brings the voltage dip and results in low reversible capacity.Herein,this work synthesized core-shell Al@C-Sn pellets for LIBs by a plus-minus strategy.In this proposal,the natural Al2O3 passivation layer is eliminated when annealing the pre-introduced SnCl2,meanwhile,polydopamine-derived carbon is introduced as dual functional shell to liberate the fresh Al core from re-oxidization and alle-viate the volume swellings.Benefiting from the addition of C-Sn shell and the elimination of the Al2O3 passivation layer,the as-prepared Al@C-Sn pellet electrode exhibits little voltage dip and delivers a reversible capacity of 1018.7 mAh·g^(-1) at 0.1 A·g^(-1) and 295.0 mAh·g^(-1) at 2.0 A·g^(-1)(after 1000 cycles),respectively.Moreover,its diffusion-controlled capacity is muchly improved compared to those of its counterparts,confirming the well-designed nanostructure contributes to the rapid Li-ion diffusion and further enhances the lithium storage activity.

关键词： lithium-ion battery high-performance anode aluminum passivation layer plus-minus strategy

Optimization of desert lake information extraction from remote sensing images using cellular automata

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International Journal of Coal Science & Technology 2023年第3期10卷 214-224页

作者： Qiuji Chen yanan cao College of Geomatics Xi'an University of Science and TechnologyXi'an 710054China

Desert lakes are important wetland resources in the blown-sand area of western China and play a significant role in maintain-ing the regional ecological environment.However,large-scale coal mining in recent years has considerably impacted the deposition condition of several lakes.Rapid and accurate extraction of lake information based on satellite images is crucial for developing protective measures against desertification.However,the spatial resolution of these images often leads to mixed pixels near water boundaries,affecting extraction precision.Traditional pixel unmixing methods mainly obtain water coverage information in a mixed pixel,making it difficult to accurately describe the spatial distribution.In this paper,the cellular automata(CA)model was adopted in order to realize lake information extraction at a sub-pixel level.A mining area in Shenmu City,Shaanxi Province,China is selected as the research region,using the image of Sentinel-2 as the data source and the high spatial resolution UAV image as the reference.First,water coverage of mixed pixels in the Sentinel-2 image was calculated with the dimidiate pixel model and the fully constrained least squares(FCLS)method.Second,the mixed pixels were subdivided to form the cellular space at a sub-pixel level and the transition rules are constructed based on the water coverage information and spatial correlation.Lastly,the process was implemented using Python and IDL,with the ArcGIS and ENVI software being used for validation.The experiments show that the CA model can improve the sub-pixel positioning accuracy for lake bodies in mixed pixel image and improve classification accuracy.The FCLS-CA model has a higher accuracy and is able to identify most water bodies in the study area,and is therefore suitable for desert lake monitor-ing in mining areas.

关键词： Blown-sand mining area Desert lake Remote sensing Mixed pixel Cellular automata

An Improved RPL Algorithm for Low-Power and Lossy Networks

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China Communications 2023年第1期20卷 140-152页

作者： yanan cao Hao Yuan Tianjin Key Laboratory of Wireless Mobile Communications and Power Transmission Tianjin Normal UniversityTianjin 300387China Chinese People’s Liberation Army Unit 61846 Zhuozhou 07250China

The routing protocol for low-power and lossy networks(RPL),standardized by Internet Engineering Task Force(IETF),is mainly designed to use for Low-power and Lossy Networks(LLNs).To solve the problems of several important routing metrics are not evaluated,the optimal path may contain long single hop links,lack of scientific multi-routing metrics evaluation method and mechanism to balance the parent child number(especially the parent with one hop away from root),this paper proposes an improved RPL algorithm for LLN(I-RPL).First of all,we propose the evaluated routing metrics:child number of parent,candidate parent number,hop count,ETX and energy consumption index.Meanwhile,we improve the path ETX calculation method to avoid selecting optimal path containing long single hop links.Then we design a novel lexical method to synthetically evaluate candidate parents.Meanwhile,based on the evaluation results of candidate parents,we design a novel objective function and a new calculation node rank method which can also be used for selecting the optimal path.Finally,evaluation results show that I-RPL outperforms ETXOF and several other improvements in terms of packet delivery ratio,latency,etc.

关键词： routing protocol RPL routing metric lexical method objective function

Characterization and spatial analysis of coseismic landslides triggered by the Luding Ms 6.8 earthquake in the Xianshuihe fault zone, Southwest China

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Journal of Mountain Science 2024年第1期21卷 160-181页

作者： GUO Changbao LI Caihong YANG Zhihua NI Jiawei ZHONG Ning WANG Meng YAN Yiqiu SONG Deguang ZHANG yanan ZHANG Xianbing WU Ruian cao Shichao SHAO Weiwei Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China Key Laboratory of Active Tectonics and Geological Safety Ministry of Natural ResourcesBeijing 100081China Research Center of Neotectonism and Crustal Stability China Geological SurveyBeijing 100081China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Sichuan Institute of Geological Survey Chengdu 610081China

On September 5, 2022, a magnitude Ms 6.8 earthquake occurred along the Moxi fault in the southern part of the Xianshuihe fault zone located in the southeastern margin of the Tibetan Plateau,resulting in severe damage and substantial economic loss. In this study, we established a coseismic landslide database triggered by Luding Ms 6.8 earthquake, which includes 4794 landslides with a total area of 46.79 km^(2). The coseismic landslides primarily consisted of medium and small-sized landslides, characterized by shallow surface sliding. Some exhibited characteristics of high-position initiation resulted in the obstruction or partial obstruction of rivers, leading to the formation of dammed lakes. Our research found that the coseismic landslides were predominantly observed on slopes ranging from 30° to 50°, occurring at between 1000 m and 2500 m, with slope aspects varying from 90° to 180°. Landslides were also highly developed in granitic bodies that had experienced structural fracturing and strong-tomoderate weathering. Coseismic landslides concentrated within a 6 km range on both sides of the Xianshuihe and Daduhe fault zones. The area and number of coseismic landslides exhibited a negative correlation with the distance to fault lines, road networks, and river systems, as they were influenced by fault activity, road excavation, and river erosion. The coseismic landslides were mainly distributed in the southeastern region of the epicenter, exhibiting relatively concentrated patterns within the IX-degree zones such as Moxi Town, Wandong River basin, Detuo Town to Wanggangping Township. Our research findings provide important data on the coseismic landslides triggered by the Luding Ms 6.8 earthquake and reveal the spatial distribution patterns of these landslides. These findings can serve as important references for risk mitigation, reconstruction planning, and regional earthquake disaster research in the earthquake-affected area.

关键词： Luding earthquake Coseismic landslides Remote sensing interpretation Spatial distribution Xianshuihe fault Earthquake fault

MetaPINNs:Predicting soliton and rogue wave of nonlinear PDEs via the improved physics-informed neural networks based on meta-learned optimization

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Chinese Physics B 2024年第2期33卷 96-107页

作者：郭亚楠曹小群宋君强冷洪泽 College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China College of Computer National University of Defense TechnologyChangsha 410073China Naval Aviation University Huludao 125001China

Efficiently solving partial differential equations(PDEs)is a long-standing challenge in mathematics and physics research.In recent years,the rapid development of artificial intelligence technology has brought deep learning-based methods to the forefront of research on numerical methods for partial differential equations.Among them,physics-informed neural networks(PINNs)are a new class of deep learning methods that show great potential in solving PDEs and predicting complex physical phenomena.In the field of nonlinear science,solitary waves and rogue waves have been important research topics.In this paper,we propose an improved PINN that enhances the physical constraints of the neural network model by adding gradient information constraints.In addition,we employ meta-learning optimization to speed up the training process.We apply the improved PINNs to the numerical simulation and prediction of solitary and rogue waves.We evaluate the accuracy of the prediction results by error analysis.The experimental results show that the improved PINNs can make more accurate predictions in less time than that of the original PINNs.

关键词： physics-informed neural networks gradient-enhanced loss function meta-learned optimization nonlinear science

A novel context-aware RPL algorithm based on a triangle module operator

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Frontiers of Information Technology & Electronic Engineering 2021年第12期22卷 1583-1597页

作者： yanan cao Hao YUAN Tianjin Key Laboratory of Wireless Mobile Communications and Power Transmission Tianjin Normal UniversityTianjin 300387China Chinese People's Liberation Army Unit 61846 Zhuozhou 072750China

For the use in low-power and lossy networks(LLNs)under complex and harsh communication conditions,the routing protocol for LLNs(RPL)standardized by the Internet Engineering Task Force is specially designed.To improve the performance of LLNs,we propose a novel context-aware RPL algorithm based on a triangle module operator(CAR-TMO).A novel composite context-aware routing metric(CA-RM)is designed,which synchronously evaluates the residual energy index,buffer occupancy ratio of a node,expected transmission count(ETX),delay,and hop count from a candidate parent to the root.CA-RM considers the residual energy index and buffer occupancy ratio of the candidate parent and its preferred parent in a recursive manner to reduce the effect of upstream parents,since farther paths are considered.CA-RM comprehensively uses the sum,mean,and standard deviation values of ETX and delay of links in a path to ensure a better performance.Moreover,in CAR-TMO,the membership function of each routing metric is designed.Then,a comprehensive membership function is constructed based on a triangle module operator,the membership function of each routing metric,and a comprehensive context-aware objective function.A novel mechanism for calculating the node rank and the mechanisms for preferred parent selection are proposed.Finally,theoretical analysis and simulation results show that CAR-TMO outperforms several state-of-the-art RPL algorithms in terms of the packet delivery ratio and energy efficiency.

关键词： Triangle module operator Membership function Context-aware Routing protocol for low-power and lossy networks(RPL) Routing metrics

RPL Based on Triangle Module Operator for AMI Networks

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China Communications 2018年第5期15卷 162-172页

作者： yanan cao Muqing Wu Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications

the routing protocol for low-power and lossy networks(RPL) has been used in advanced metering infrastructure(AMI)which could provide two-way communication between smart meters and city utilities.To improve the network performance of AMI networks, this paper proposed an improved algorithm of RPL based on triangle module operator(IAR-TMO). IAR-TMO proposes membership functions of the following five typical routing metrics: end-to-end delay, number of hops, expected transmission count(ETX),node remaining energy, and child node count.Moreover, IAR-TMO uses triangle module operator to fuse membership functions of these routing metrics. Then, IAR-TMO selects preferred parents(the next hop) based on the triangle module operator. Theoretical analysis and simulation results show that IAR-TMO has a great improvement when compared with two recent representative algorithms: ETXOF(ETX Objective Function) and OF-FL(Objective Function based on Fuzzy Logic), in terms of network lifetime, average end-to-end delay,etc. Consequently, the network performances of AMI networks can be improved effectively.

关键词：网络性能 AMI 操作员 RPL 模块三角路由协议改进算法

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在线社交网络中用户地理位置预测综述

计算机研究与发展 2024年第2期61卷 385-412页

作者：刘乐源代雨柔曹亚男周帆电子科技大学信息与软件工程学院成都610054 中国科学院信息工程研究所北京100093

随着智能移动终端的日益普及,人们越来越多地利用社交网络平台(如Twitter、新浪微博等)获取信息、评论和交流.虽然全球卫星定位系统(GPS)设备能够精确获取位置信息,但是大量用户出于隐私和安全的考虑不会直接共享自己的位置信息.因此,... 详细信息

随着智能移动终端的日益普及,人们越来越多地利用社交网络平台(如Twitter、新浪微博等)获取信息、评论和交流.虽然全球卫星定位系统(GPS)设备能够精确获取位置信息,但是大量用户出于隐私和安全的考虑不会直接共享自己的位置信息.因此,如何获取在线用户的地理位置成为了一个前沿的研究领域以及学术界和工业界共同关注的重要课题,并且成为众多下游应用的基础,例如基于位置的定向广告投放、事件/地点的推荐、自然灾害或疾病预警和网络犯罪的追踪等.详细总结了预测社交网络用户地理位置的方法、数据、评价体系和基础算法.首先,归纳了不同的定位任务以及相应的评价指标;其次,针对不同的任务梳理所用的数据类型和数据融合方式,并且,详尽分析了已有的信息抽取和特征选择方式及其优缺点;再次,对现有定位模型和算法进行分类,从地名词典、传统机器学习和深度学习3个方面对用户定位方法进行阐述和分析;最后,总结了社交网络用户地理位置预测的难点和面临的挑战,并展望该领域的发展趋势和未来研究所需要关注的方向.

关键词：社交网络地理位置预测数据分析与融合信息抽取时空特征