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Tunable Co/ZnO/C@MWCNTs based on carbon nanotube-coated MOF with excellent microwave absorption properties

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Journal of Materials Science & Technology 2022年第32期127卷 153-163页

作者： Zirui Jia Mingyue Kong bowen yu Yingzhuo Ma Jiaying Pan Guanglei Wu Institute of Materials for Energy and Environment State Key Laboratory of Bio-Fibers and Eco-TextilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China Weihai Innovation Institute Qingdao UniversityWeihai 264200China

The development of global information technology makes human life intelligent,and the large-scale use of various electronic devices increases the electromagnetic radiation in the surrounding *** has created a requirement for the development of high-performance electromagnetic wave absorbers to eliminate electromagnetic ***,the preparation of electromagnetic wave absorbers with excellent electromagnetic loss capability remains a great ***,we present a method to prepare Co/ZnO/C@MWCNTs(CZC@M)composites by pyrolysis of ZnCo-MOF@MWCNTs(MOF@M).Specifically,MWCNTs are uniformly distributed on the CZC surface to form multiple heterogeneous interfaces,which will lead to an increase in *** addition,changing the amounts of MWCNTs in the composite can modulate its dielectric constant and impedance matching ***,at only 10%sample content,the minimum reflection loss of-41.75 d B and the maximum effective absorption bandwidth of 4.72 GHz are obtained at thicknesses of 2.4 mm and 2.2 mm,***,the results reported in this work provide a new design strategy for the synthesis of high-performance electromagnetic wave absorbers with potential applications in the elimination of electromagnetic pollution.

关键词： MWCNTs Metal organic frameworks CZC@M Microwave absorption

Building durable climate clubs:Lessons from a comparative study of the APP and CEM

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Chinese Journal of Population,Resources and Environment 2021年第2期19卷 117-124页

作者： bowen yu Steven Bernstein Matthew Hoffmann School of International Relations and Public Affairs Fudan UniversityShanghai200433China Department of Political Science the University of TorontoTorontoM5S 3G3Canada

Climate clubs are valuable platforms for international and public-private collaboration in global climate governance;however,not all climate clubs enjoy durable support from their *** existing literature attributes the varied fates of climate clubs to factors like legitimacy and club *** further argue that the norm-making function of clubs,the perceived value of club goods,and the costs of club good production collectively affect club *** present a comparative study on two U.S.-initiated climate clubs-the Asia-Pacific Partnership on Clean Development and Climate(APP)and the Clean Energy Ministerial(CEM).While legitimacy concerns had some marginal influence on both clubs,the niche clubs occupy and the costs of club goods provision were crucial factors that influenced the two clubs’different *** APP’s failure was due to its focus on norm-making and providing information-oriented assistance to the private *** government interest in norm-making declined,the APP’s value declined ***,assistance to private sector actors was costly and less attractive to *** comparison,the CEM found its niche by focusing on facilitating policymaking in the clean energy sector in a cost-efficient *** make clubs durable,constructing an action-oriented working environment and providing value-added and low-cost services to key stakeholders are of great importance.

关键词： Climate club Legitimacy Club goods APP CEM

Macroscopic electromagnetic synergy network-enhanced N-doped Ni/C gigahertz microwave absorber with regulable microtopography

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Nano Research 2023年第7期16卷 10666-10677页

作者： yuelei Pan Qianqian Zhu Jiahui Zhu yuhang Cheng bowen yu Zirui Jia Guanglei Wu Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China

To achieve excellent electromagnetic wave(EMW)absorption properties,the microstructure design of the absorber is *** this work,six kinds of N-Ni/C nanostructures with different morphologies were prepared by one-step hydrothermal method and high temperature carbonization by adjusting the types of nickel salts and reaction *** EMW absorption performance of six different morphologies of N-Ni/C nanostructures was compared and *** them,it is found that the nanoflowerlike N-Ni/C composite has excellent dielectric loss and magnetic loss synergistic effect due to its polycrystalline structure,and can obtain excellent EMW absorption *** minimum reflection loss value at a thickness of 1.9 mm is-59.56 dB at 16.88 GHz,and the effective absorption bandwidth value reaches 6.0 GHz at a thickness of 2.2 *** research shows that different morphologies and multiple lattice structures of nanostructures with the same composition have a significant influence on EMW absorption performance,which provides new research ideas for developing high-performance EMW absorbing materials.

关键词： magnetic metal-carbon binary composition morphology control dielectric loss magnetic loss electromagnetic wave absorption

Insight into the Dual Cycle Mechanism of Methanol-to-OIefins Reaction over SAPO-34 Molecular Sieve by Isotopic Tracer Studies

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Chemical Research in Chinese Universities 2020年第6期36卷 1203-1208页

作者： yu bowen LOU Caiyi ZHANG Wenna XU Shutao HAN Jingfeng yu Zhengxi WEI Yingxu LIU Zhongmin National Engineering Laboratory for Methanol to Olefins Dalian National Laboratory for Clean EnergyiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023P.R.China University of Chinese Academy of Sciences Beijing 100039P.R.China

Methanol-to-olefins(MTO)reaction is one of the important non-petroleum routes to produce light olefinsover acidic molecular *** this study,the complete reaction course of MTO on SAPO-34 molecular sieve with retained organics evolution from induction period to deactivation period was investigated systematically at different weight hourly space velocities(WHSV)of *** the aid of 12C/3C-methanol isotopic switch experiment,the dual cycle mechanism involving aromatics-based cycle and alkenes-based cycle was evaluated during the whole reac-tion *** detailed reaction route varied with the evolution of the retained organics in the catalyst at different reaction *** aromatics-based cycle and alkenes-based cycle alternately dominate the reaction *** the efficient reaction period,aromatics-based cvcle is the main reaction mechanism,while in the induction and deactiva-tion *** contribution of alkenes-based cvcle mechanism will become more important.

关键词： SAPO-34 Methanol-to-olefin(MTO) Polymethy Ibenzene Dual-cycle mechanism Isotopic tracer

LotusSQL:SQL Engine for High-Performance Big Data Systems

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Big Data Mining and Analytics 2021年第4期4卷 252-265页

作者： Xiaohan Li bowen yu Guanyu Feng Haojie Wang Wenguang Chen Department of Computer Science and Technology Tsinghua UniversityChina

In recent years,Apache Spark has become the de facto standard for big data *** is a module offering support for relational analysis on Spark with Structured Query Language(SQL).SparkSQL provides convenient data processing *** its efficient optimizer,SparkSQL still suffers from the inefficiency of Spark resulting from Java virtual machine and the unnecessary data serialization and *** native languages such as C++could help to avoid such *** from a bare-metal runtime environment and template usage,systems with C++interfaces usually achieve superior ***,the complexity of native languages also increases the required programming and debugging *** this work,we present LotusSQL,an engine to provide SQL support for dataset abstraction on a native backend *** employ a convenient SQL processing framework to deal with frontend *** query optimization technologies are added to improve the quality of execution *** the storage design and user interface of the compute engine,LotusSQL implements a set of structured dataset operations with high efficiency and integrates them with the *** results show that LotusSQL achieves a speedup of up to 9 in certain queries and outperforms Spark SQL in a standard query benchmark by more than 2 on average.

关键词： big data C++ Structured Query Language(SQL) query optimization

A Joint Learning Framework for the CCKS-2020 Financial Event Extraction Task

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Data Intelligence 2021年第3期3卷 444-459页

作者： Jiawei Sheng Qian Li Yiming Hei Shu Guo bowen yu Lihong Wang Min He Tingwen Liu Hongbo Xu Institute of Information Engineering Chinese Academy of SciencesBeijing 100093China School of Cyber Security University of Chinese Academy of SciencesBeijing 100049China School of Computer Science Beihang UniversityBeijing 100191China School of Cyber Science and Technology Beihang UniversityBeijing 100191China National Computer Network Emergency Response Technical Team/Coordination Center of China Beijing 100029China

This paper presents a winning solution for the CCKS-2020 financial event extraction task, where the goal is to identify event types, triggers and arguments in sentences across multiple event types. In this task, we focus on resolving two challenging problems(i.e., low resources and element overlapping) by proposing a joint learning framework, named SaltyFishes. We first formulate the event extraction task as a joint probability model. By sharing parameters in the model across different types, we can learn to adapt to low-resource events based on high-resource events. We further address the element overlapping problems by a mechanism of Conditional Layer Normalization, achieving even better extraction accuracy. The overall approach achieves an F1-score of 87.8% which ranks the first place in the competition.

关键词： Event detection Event extraction Joint learning Financial event

＂Smart Cafe＂： A Mobile Local Computing System Based On Indoor Virtual Cloud

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China Communications 2014年第4期11卷 38-49页

作者： PU Lingjun XU Jingdong yu bowen ZHANG Jianzhong College of Computer and Control Engineering Nankai University Tianjin 300071 China

With network developing and virtualization rising, more and more indoor environment （POIs） such as care, library, office, even bus and subway can provide plenty of bandwidth and computing resources. Meanwhile many people daily spending much time in them are still suffering from the mobile device with limited resources. This situation implies a novel local cloud computing paradigm in which mobile device can leverage nearby resources to facilitate task execution. In this paper, we implement a mobile local computing system based on indoor virtual cloud. This system mainly contains three key components： 1）As to application, we create a parser to generate the ＂method call and cost tree＂ and analyze it to identify resource- intensive methods. 2） As to mobile device, we design a self-learning execution controller to make offtoading decision at runtime. 3） As to cloud, we construct a social scheduling based application-isolation virtual cloud model. The evaluation results demonstrate that our system is effective and efficient by evaluating CPU- intensive calculation application, Memory- intensive image translation application and I/ O-intensive image downloading application.

关键词： mobile local computing system application partition dynamic offloading strategy virtual cloud model social scheduling

Methane and nitrous oxide emissions from municipal wastewater treatment plants in China:A plant-level and technology-specific study

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Environmental Science and Ecotechnology 2024年第4期20卷 123-130页

作者： Haiyan Li Liangfang You He Du bowen yu Lu Lu Bo Zheng Qiang Zhang Kebin He Nanqi Ren School of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhen518055China Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration Institute of Environment and EcologyTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing100084China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China

Wastewater treatment is an important source of greenhouse gases(GHGs).Yet large uncertainties remain in the quantification of GHG emissions from municipal wastewater treatment plants(MWWTPs)in China.A high-resolution and technology-specific emission inventory is still lacking to support mitigation strategies of *** we develop a plant-level and technology-based MWWTP emission inventory for China covering 8703 plants and 19 treatment technology categories by compiling and harmonizing the most up-to-date facility-level ***'s methane(CH_(4))and nitrous oxide(N_(2)O)emissions from MWWTPs in 2020 are estimated to be 150.6 Gg and 22.0 Gg,respectively,with the uncertainty range of-30%to 37%and-30%to 26%at 95%confidence *** find an emission inequality across cities,with the richest cities emitting two times more CH_(4)and N_(2)O per capita from municipal wastewater treatment than the poorest *** emitted CH_(4)and N_(2)O are dominated by Anaerobic/Anoxic/Oxic-,Sequencing Batch Reactor-,Oxidation Ditch-,and Anoxic/Oxic-based MWWTPs of less than 20 years *** the relatively young age structure of China's MWWTPs,the committed emissions highlight the importance of reducing on-site GHG emissions by optimization of operating conditions and innovation *** emission differences among our estimates,previous studies,and the Intergovernmental Panel on Climate Change guidelines are largely attributed to the uncertainties in emission factors,implying the urgent need for more plant-integrated measurements to improve the accuracy of emission accounting.

关键词： Methane Nitrous oxide Emissions Municipal wastewater treatment plants

Microstructures and Properties of Copper-steel Welded Joint by Twin Wire Welding

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稀有金属材料与工程 2011年第S4期40卷 302-305页

作者： yu Jin,Wu bowen,Zheng Shubao,Wang Kehong,Zhou QiSchool of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China Nanjing Univ Sci & Technol Sch Mat Sci & Engn Nanjing 210094 Jiangsu Peoples R China

The paper studies the twin wire butt welding of 6mm-thick T2 copper and Q235 steel plate by using the twin wire consisting of one copper-plated welding wire and one steel welding *** to the appearance detection,the weld joint gained is sound in shape without crackles,pores,incomplete fusion and other *** shown by the mechanical property,SEM and EDAX and in the metallographic analysis and test,the rupture position of copper-steel welded joint is located in the copper-part HAZ when the tensile strength reaches above 210MPa and Fe content of the welded joint involved in 1# test specimen reaches around 22.78%-26.75%,with the hardness achieving between 102～107HB and the weld structure being (α+ε) duplex solid solution.

关键词： copper-steel welded joint twin-wire welding mechanical property metallurgical structure