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Propagation form of internal cracks induced by continuous casting soft reduction and control strategy for internal quality

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Journal of Iron and Steel Research International 2024年第3期31卷 622-633页

作者： Pu Wang Liang Chen Qun-wei Tang Wei-tao Li Shao-xiang Li Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Weifang Special Steel Group co..ltd. Weifang 262400ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The propagation form of internal cracks induced by continuous casting soft reduction and the control strategy for enhancing the internal quality of 45 steel through industrial trials and a three-dimensional flow-heat transfer-solidification coupling model were *** results showed that the internal cracks induced by soft reduction exhibited a characteristic of being"coarse in the middle and fine at both ends",and displayed an elliptical arc distribution on the loose side of the strand cross *** cracks originated within the brittle temperature range and propagated inward to the liquid impenetrable temperature and outward to the zero ductility temperature or *** control strategy for enhancing the internal quality of the 45 steel strand through soft reduction is to adjust the casting speed or the reduction zone appropriately,ensuring that the central solid fraction of the reduction zone falls within the range of *** this point,a reasonable reduction amount is allocated to eliminate the center shrinkage cavities and center segregation,even if it results in minor reduction-induced cracks.

关键词： continuous casting Soft reduction Crack propagation Internal quality control strategy

Molecular Dynamics Simulation of Shock Response of CL-20 co-crystals containing Void Defects

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Defence technology（防务技术） 2024年第1期31卷 364-374页

作者： Changlin Li Wei Yang Qiang Gan Yajun Wang Lin Liang Wenbo Zhang Shuangfei Zhu Changgen Feng State Key Laboratory of Explosion Science and technology Beijing Institute of TechnologyBeijing 100081China School of Materials Science&Engineering Beijing Institute of TechnologyBeijing 100081China

To investigate the effect of void defects on the shock response of hexanitrohexaazaisowurtzitane(CL-20)co-crystals,shock responses of CL-20 co-crystals with energetic materials ligands trinitrotoluene(TNT),1,3-dinitrobenzene(DNB),solvents ligands dimethyl carbonate(DMC) and gamma-butyrolactone(GBL)with void were simulated,using molecular dynamics method and reactive force *** is found that the CL-20 co-crystals with void defects will form hot spots when impacted,significantly affecting the decomposition of molecules around the *** degree of molecular fragmentation is relatively low under the reflection velocity of 2 km/s,and the main reactions are the formation of dimer and the shedding of nitro *** existence of voids reduces the safety of CL-20 co-crystals,which induced the sensitivity of energetic co-crystals CL-20/TNT and CL-20/DNB to increase more *** has occurred under the reflection velocity of 4 km/s,energetic co-crystals are easier to polymerize than solvent co-crystals,and are not obviously affected by *** results show that the energy of the wave decreases after sweeping over the void,which reduces the chemical reaction frequency downstream of the void and affects the detonation performance,especially the solvent co-crystals.

关键词： CL-20 co-crystals Molecular dynamics simulation Reactive forcefield Impact response Hot spot Void defect

Ground target localization of unmanned aerial vehicle based on scene matching

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High technology Letters 2024年第3期30卷 231-243页

作者： ZHANG Yan CHEN Yukun HUANG He TANG Simi LI Zhi beijing Yansou technology co. Ltd.Beijing 100085P.R.China The 15th Research Institute of China Electronics technology Group corporation Beijing 100083P.R.China

In order to improve target localization precision,accuracy,execution efficiency,and application range of the unmanned aerial vehicle(UAV)based on scene matching,a ground target localization method for unmanned aerial vehicle based on scene matching(GTLUAVSM)is *** sugges-ted approach entails completing scene matching through a feature matching ***,multi-sensor registration is optimized by robust estimation based on homologous ***,basemap generation and model solution are utilized to improve basemap correspondence and accom-plish aerial image *** evidence and experimental verification demonstrate that GTLUAVSM can improve localization accuracy,speed,and precision while minimizing reliance on task equipment.

关键词： scene matching basemap adjustment feature registration random sample con-sensus(RANSAC) unmanned aerial vehicle(UAV)

The exploration and practice of low-altitude airspace flight service and traffic management in China

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Green Energy and Intelligent Transportation 2024年第2期3卷 1-8页

作者： Xiangmin Guan Hongxia Shi Dongsong Xu Binhua Zhang Jian Wei Jun Chen CAAC Key Laboratory of General Aviation Operation Department of General AviationCivil Aviation Management Institute of ChinaBeijing 100102China Research Institute of Civil Aviation Regulations and Standardization China Academy of Civil Aviation Science and TechnologyBeijing 100028China Department of technology Platform Phoenix Wings Technology(Shen zhen)Co.LtdShenZhen 518054China Shenzhen Highgreat Innovation technology Development co. Ltd dShenzhen 518000China School of Engineering and Materials Science Queen Mary University of LondonLondonE14NSUK

Due to the inherent nature of being highly digitalized,networked and intelligent,Unmanned Aerial System(UAS)operations pose a huge challenge to traditional aviation regulation and technical *** to keep safe,efficient and integrated operation for different Airspace users has become a pressing issue faced by civil aviation around the *** paper focuses on the main operational scenarios and characteristics of unmanned aviation development in *** operational characteristics and associated challenges due to diverse low-altitude users are analyzed,including operation concepts,UAS traffic management,technological test and verification,and *** light on the practices in Europe and the United States,this paper summarizes China's practices and progress in low-altitude operations management,and analyzes future technological development needs and trends,as well as feasible implementation pathways and measures based on actual needs.

关键词： UAS Low-altitude airspace UAS traffic management Exploration and practice

Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

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Chinese Journal of Chemical Engineering 2024年第2期66卷 216-223页

作者： Yinghui Liu Shaoduo Liu Xiaosheng Wang Hongjing Wang Ranjia Li Changchun Yu Chunming Xu Yuxiang Liu Zhengqiu Xie Yongqiang Wang Pan Tang State Key Laboratory of Heavy Oil Processing College of New Energy and MaterialsChina University of Petroleum-BeijingBeijing 102249China Synfuels China technology co. LtdBeijing 101400China college of Chemical Engineering Qingdao University of Science&TechnologyQingdao 266042China Yueyang Jucheng Chemical co. LtdYueyang 414009China

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation *** influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically *** characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples *** amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly *** Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization *** high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic *** increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.

关键词： Carbonylation Dimethyl ether Solvent-free Zeolite Synthesis Catalysis

Low-temperature graphitization of lignin via co-assisted electrolysis in molten salt

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Green Energy & Environment 2024年第9期9卷 1449-1458页

作者： Shijie Li Wei-Li Song Xue Han Qingqing Cui Yan-li Zhu Shuqiang Jiao Institute of Advanced Structure technology Beijing Institute of Technology State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing State Key Laboratory of Explosion Science and technology Beijing Institute of Technology

The ever-growing energy demand and environmental issues have stimulated the development of sustainable energy ***,an efficient and environmentally friendly electrochemical transformation technology was proposed to prepare highly graphitized carbon materials from an abundant natural resource-lignin （LG）.The preparation process mainly includes pyrolytic carbonization of raw LG material and electrochemical conversion of amorphous carbon ***,with the assistance of co catalyst,the graphitization degree of the products was significantly improved,in which the mechanism was the removal of heteroatoms in LG and the rearrangement of carbon atoms into graphite ***,tunable microstructures （nanoflakes） under catalytic effects could also be observed by controlling the electrolytic *** with the products CN1 （without catalyst） and CN5 （with 10%catalyst）,the specific surface area are 158.957 and202.246 m2g-1,*** used as the electrode material for lithium-ion batteries,CN5 delivered a competitive specific capacity of～350 m Ah g-1（0.5 C） compared with commercial *** strategy proposed in this work provides an effective way to extract value-added graphite materials from lignin and can be extended to the graphitization conversion of any other amorphous carbon precursor materials.

关键词： Lignin Graphitic carbon Electrochemical conversion Lithium-ion batteries

The difference of the ionomer–catalyst interfaces for poly(aryl piperidinium)hydroxide exchange membrane fuel cells and proton exchange membrane fuel cells

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Nano Research 2024年第7期17卷 6102-6110页

作者： Xuerui Liu Xingdong Wang Chanyu Zhang Yun Cai Bowen Chen Dongyue Xin Xiaoxiao Jin Wei Zhu Klaus Wippermann Hui Li Ruiyu Li Zhongbin Zhuang beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China State Key Lab of Organic-Inorganic composites Beijing University of Chemical TechnologyBeijing 100029China Research Institute of Petroleum Processing SINOPECBeijing 100083China DeepHytec co. Ltd.Shenzhen 518118China Institute of Energy and Climate Research(IEK-14) Forschungszentrum Jülich GmbHJülich 52425Germany beijing Key Laboratory of Energy Environmental Catalysis Beijing University of Chemical TechnologyBeijing 100029China

The microstructures of the ionomer–catalyst interfaces in the catalyst layers are important for the fuel cell performance because they determine the distribution of the active triple-phase ***,we investigate the ionomer–catalyst interactions in hydroxide exchange membrane fuel cells(HEMFCs)using poly(aryl piperidinium)and compare them with proton exchange membrane fuel cells(PEMFCs).It is found that different catalyst layer microstructures are between the two types of fuel *** ionomer/carbon(I/C)ratio does not have a remarkable impact on the HEMFC performance,while it has a strong impact on the PEMFC performance,indicating the weaker interaction between the HEMFC ionomer and *** dynamics simulations demonstrate that the HEMFC ionomer tends to distribute on the carbon support,unlike the PEMFC ionomer,which heavily covers the Pt *** results suggest that the poisoning effect of the ionomer on the catalyst is much weaker in HEMFCs,and the improved ionomer/catalyst interaction is beneficial for the HEMFC performances.

关键词： hydroxide exchange membrane fuel cells catalysts ionomer oxygen reduction reaction interfaces

computing Power Network:A Survey

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China communications 2024年第9期21卷 109-145页

作者： Sun Yukun Lei Bo Liu Junlin Huang Haonan Zhang Xing Peng Jing Wang Wenbo School of Information and communications Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Research Institute of China Telecom co. Ltd.Beijing 102209China beijing Branch of China Telecom co. Ltd.Beijing 100032China

With the rapid development of cloud computing,edge computing,and smart devices,computing power resources indicate a trend of ubiquitous *** traditional network architecture cannot efficiently leverage these distributed computing power resources due to computing power island *** overcome these problems and improve network efficiency,a new network computing paradigm is proposed,i.e.,computing Power Network(CPN).computing power network can connect ubiquitous and heterogenous computing power resources through networking to realize computing power scheduling *** this survey,we make an exhaustive review on the state-of-the-art research efforts on computing power *** first give an overview of computing power network,including definition,architecture,and ***,a comprehensive elaboration of issues on computing power modeling,information awareness and announcement,resource allocation,network forwarding,computing power transaction platform and resource orchestration platform is *** computing power network testbed is built and *** applications and use cases in computing power network are ***,the key enabling technologies for computing power network are ***,open challenges and future research directions are presented as well.

关键词： computing power modeling computing power network computing power scheduling information awareness network forwarding

FPGA and computer-vision-based atom tracking technology for scanning probe microscopy

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Chinese Physics B 2024年第5期33卷 76-85页

作者：俞风度刘利王肃珂张新彪雷乐黄远志马瑞松郇庆 beijing National Laboratory for condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China ACME (beijing) technology co. Ltd.Beijing 101407China Key Laboratory for Vacuum Physics University of Chinese Academy of SciencesBeijing 100190China

Atom tracking technology enhanced with innovative algorithms has been implemented in this study,utilizing a comprehensive suite of controllers and software independently developed *** an on-board field-programmable gate array(FPGA)with a core frequency of 100 MHz,our system facilitates reading and writing operations across 16 channels,performing discrete incremental proportional-integral-derivative(PID)calculations within 3.4 *** upon this foundation,gradient and extremum algorithms are further integrated,incorporating circular and spiral scanning modes with a horizontal movement accuracy of 0.38 *** integration enhances the real-time performance and significantly increases the accuracy of atom *** tracking achieves an equivalent precision of at least 142 pm on a highly oriented pyrolytic graphite(HOPG)surface under room temperature atmospheric *** applying computer vision and image processing algorithms,atom tracking can be used when scanning a large *** techniques primarily consist of two algorithms:the region of interest(ROI)-based feature matching algorithm,which achieves 97.92%accuracy,and the feature description-based matching algorithm,with an impressive 99.99%*** implementation approaches have been tested for scanner drift measurements,and these technologies are scalable and applicable in various domains of scanning probe microscopy with broad application prospects in the field of nanoengineering.

关键词： atom tracking FPGA computer vision drift measurement