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Fluorinated graphite nanosheets for ultrahigh-capacity lithium primary batteries

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Rare Metals 2021年第7期40卷 1708-1718页

作者： Xiao-Xia Yang guan-jun zhang Bao-Sheng Bai Yu Li Yi-Xiao Li Yong Yang Xian Jian Xi-Wen Wang Tianjin Lishen Special Power Supply Science and Technology Joint-Stock Co. Tianjin 300393China Tianjin Lishen Battery Joint-Stock Co. LtdTianjin 300384China School of Materials Science and Engineering Tianjin UniversityTianjin 300354China State Key Laboratory for Physical Chemistry of Solid Surface Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China

For better performances of Ni-based catalysts at low temperatures,Ni/SiC catalyst doped with a little amount of additive La was successfully *** catalytic CO methanation activity tests showed that 3%La-Ni/SiC catalyst was excellent at a low reaction temperature(95.9%CO conversion and 85.1%CH4 selectivity at250℃)with a superior stability compared with Ni/SiC(3.4%CO conversion and 0%CH4 selectivity at 250℃).This can be attributed to that the addition of La can markedly improve the dispersibility of active metal Ni and reduce the particle sizes of Ni nanoparticles or clusters,and can also regulate the interaction between active components and ***,the high thermal conductivity and thermal stability could avoid the generation of hot spots in the catalyst *** results will promote the development of highly active Ni-based catalysts for the low-temperature methanation reaction.

关键词： Graphite nanosheets Carbon fluoride Primary battery Electrolyte Soft pack battery

3D particle‐in‐cell simulation of positive streamer initiation in highly pressurized gaseous,liquid and supercritical CO_(2)with field ionization

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High Voltage 2021年第1期6卷 16-24页

作者： Muhammad Farasat Abbas Xu‐Chu Yuan Han‐Wei Li Jian‐Yi Xue An‐Bang Sun guan‐jun zhang State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'anShaanxiChina

A 3D particle‐in‐cell/Monte Carlo collision model is used to investigate the streamer discharge inception in CO_(2) at elevated pressures including gaseous, liquid and supercritical phases. Generation of free electrons is a prerequisite for initiation and development of positive streamers. Field ionization from impurity molecules of low density and low ionization energy is assumed as the source of primary ionization in the model. The field dependent generation rate of electrons is calculated by Zener's model. Tree‐like streamer with filamentary shape presents at the needle tip and propagates to-wards the plane electrode in all three phases of CO_(2), with differing in length and propagation speed. Furthermore, the influence of different parameters such as applied voltage, electrode tip size, and ionizable density and ionization potential of impurity molecules on the evolution of streamer discharge in supercritical CO_(2) are investigated. Simulation results obtained from the 3D model agree well with experimental observations in the literature, which show that field ionization might be one of possible ionization sources in pressurized CO_(2) in the presence of high electric field.

关键词： field. ionization gaseous

Skeletal phenotypes and molecular mechanisms in aging mice

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Zoological Research 2024年第4期45卷 724-746页

作者： Qiao guan Yuan zhang Zhi-Kun Wang Xiao-Hua Liu jun Zou Ling-Li zhang School of Exercise and Health Shanghai University of SportShanghai 200438China College of Athletic Performance Shanghai University of SportShanghai 200438China

Aging is an inevitable physiological process,often accompanied by age-related bone loss and subsequent bone-related diseases that pose serious health *** on skeletal diseases caused by aging in humans is challenging due to lengthy study durations,difficulties in sampling,regional variability,and substantial ***,mice are preferred for such studies due to their similar motor system structure and function to humans,ease of handling and care,low cost,and short generation *** this review,we present a comprehensive overview of the characteristics,limitations,applicability,bone phenotypes,and treatment methods in naturally aging mice and prematurely aging mouse models(including SAMP6,POLG mutant,LMNA,SIRT6,ZMPSTE24,TFAM,ERCC1,WERNER,and KL/KL-deficient mice).We also summarize the molecular mechanisms of these aging mouse models,including cellular DNA damage response,senescence-related secretory phenotype,telomere shortening,oxidative stress,bone marrow mesenchymal stem cell(BMSC)abnormalities,and mitochondrial ***,this review aims to enhance our understanding of the pathogenesis of aging-related bone diseases.

关键词： Aging Premature aging Mice Bone Gene knockout

An analysis on dealing with audit failure

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Journal of Modern Accounting and Auditing 2009年第7期5卷 62-65页

作者： zhang guan-jun zhang Lin School of Accounting Zhongnan University of Economics and Law Wuhan 430074 China

Many highly publicized accounting scandals of the recent past seriously caused enormous losses to investors, hindered the healthy development of the capital market and damaged the credibility of the accounting profess... 详细信息

关键词： CPA audit failure countermeasures

The reservoir characteristics and their controlling factors of the sublacustrine fan in the Paleogene Dongying Formation, Bohai Sea,China

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Journal of Palaeogeography 2024年第1期13卷 127-148页

作者： Xiao-jun Pang guan-Min Wang Meng Zhao Qing-Bin Wang Xue-Fang zhang School of Geosciences China University of Petroleum(East China)QingdaoShandong 266580China Tianjin Branch of China National Offshore Oil Corporation Limited Tianjin 300459China

Sublacustrine fan is an important element in continental lacustrine basins and is significant for reservoir exploration. Oil and gas resources have been found in the sublacustrine fan sandstone reservoirs of the Paleogene Dongying Formation in the Bohai Sea. In this study, the characteristics of the sublacustrine fan reservoirs and the controlling factors are studied using information from logging, cores, physical properties,casting thin sections, X-ray diffraction of clay minerals, vitrinite reflectance, rock pyrolysis, manometry data,and 3D seismic data. The sublacustrine fans of the Dongying Formation in the LD10, QHD34, and BZ21 structures show high-quality reservoirs with porosity >15 % and permeability >5 m D. The main controlling factors of the high-quality reservoirs are attributed to the favorable sedimentary facies type and negligible compaction,and cementation, substantial dissolution of K-feldspar, overpressure, and the development of faults and fractures. A high-quality sublacustrine fan reservoir model has been established to explain how these factors affected the physical properties. The favorable targets for oil and gas exploration in the Dongying Formation of Bohai Sea include undercompacted sandy debris flow reservoirs showing the dissolution of K-feldspar, and the reservoirs which are connected to the source rocks by faults. This study provides insights to establish the relationship between sedimentology, diagenesis and reservoir quality. The results of this study are significant for the exploration and development of the sublacustrine fan sandstone reservoirs in the Bohai Sea and analogous sandstone reservoirs elsewhere.

关键词： Sublacustrine fan High-quality reservoir Dissolution Overpressure Fault Bohai Sea

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

Dynamic Couplingand Cooperative Control for Multi-paralleled Doubly Fed Induction Generator Wind Farms during Symmetrical Low Voltage Ride-through in a Weak Grid

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Protection and Control of Modern Power Systems 2024年第3期9卷 112-125页

作者： Lei guan jun Yao the College of Electrical Engineering at Chongqing University ChongqingChina the State Key Laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China

In multi-fed grid-connected systems,there are complex dynamic interactions between different pieces of *** in situations of weak-grid faults,the dynamic coupling between equipment becomes more *** may cause the system to experience small-signal instability during the fault *** this paper,multi-paralleled doubly fed induction generator(DFIG)-based wind farms(WFs)are taken as an example to study the dynamic coupling within a multi-fed system during fault steady-state of symmetrical low voltage ride-through(LVRT)in a weak *** analysis reveals that the dynamic coupling between WFs will introduce a damping shift to each *** inevitably affects the system’s dynamic stability and brings the risk of small-signal instability during fault steady-state in LVRT *** the distance to fault location and fault severity will exacerbate the dynamic coupling between *** of the dynamic coupling,adjusting the control state of one WF will affect the stability of the remaining WFs in the ***,a cooperative control strategy for multi-paralleled DFIG WFs is proposed to improve dynamic stability during *** analysis and the effectiveness of the proposed control strategy are verified by modal analysis and simu-lation.

关键词： Doubly fed induction generator(DFIG) wind farms(WFs) dynamic stability low voltage ride through(LVRT) weak grid dynamic coupling

W-band millimeter wave vialess microstrip-to-microstrip vertical transition in multilayer LCP substrate

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The Journal of China Universities of Posts and Telecommunications 2024年第3期31卷 87-94页

作者： Liu Weihong zhang Xu guan Dongyang School of Electronic Engineering Xian University of Posts and TelecommunicationsXi'an 710121China

In this paper,a W-band broadband vialess microstrip(MS)-to-MS vertical transition in multilayer liquid crystal polymer(LCP)substrate is presented,which consists of two MS lines in the top layer,a common ground plane and slotline resonators in the second layer,and a close-loop transmission-line in the third *** increase the passband of the vialess vertical transition,an H-shaped slotline resonator is introduced,which greatly improves the impedance performance of the slotline resonator,and the full-wave simulated results indicate that insertion loss(IL)is less than 2 dB and return loss(RL)is better than 10 dB at *** verify this design,the broadband vertical transition is fabricated and *** measured results indicate that a broadband vertical transition with RL better than 10 dB and IL less than 5.67 dB can be obtained in the frequency range from 70.00 GHz to 104.09 *** to the fabrication error in the preparation process,the measured results are deteriorated compared to the simulated results,and the investigation indicates that the deviation is caused by the thickness error of the LCP substrate.

关键词： W-band broadband microstrip(MS)-to-MS vialess vertical transition liquid crystal polymer(LCP)

Hadoop-based secure storage solution for big data in cloud computing environment

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Digital Communications and Networks 2024年第1期10卷 227-236页

作者： Shaopeng guan Conghui zhang Yilin Wang Wenqing Liu School of Information and Electronic Engineering Shandong Technology and Business UniversityYantai264003China

In order to address the problems of the single encryption algorithm,such as low encryption efficiency and unreliable metadata for static data storage of big data platforms in the cloud computing environment,we propose a Hadoop based big data secure storage ***,in order to disperse the NameNode service from a single server to multiple servers,we combine HDFS federation and HDFS high-availability mechanisms,and use the Zookeeper distributed coordination mechanism to coordinate each node to achieve dual-channel ***,we improve the ECC encryption algorithm for the encryption of ordinary data,and adopt a homomorphic encryption algorithm to encrypt data that needs to be *** accelerate the encryption,we adopt the dualthread encryption ***,the HDFS control module is designed to combine the encryption algorithm with the storage *** results show that the proposed solution solves the problem of a single point of failure of metadata,performs well in terms of metadata reliability,and can realize the fault tolerance of the *** improved encryption algorithm integrates the dual-channel storage mode,and the encryption storage efficiency improves by 27.6% on average.

关键词： Big data security Data encryption Hadoop Parallel encrypted storage Zookeeper