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Boosting the polysulfide confinement in B/N–codoped hierarchically porous carbon nanosheets via Lewis acid–base interaction for stable Li–S batteries

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Journal of Energy Chemistry 2020年第12期29卷 90-100页

作者： dong-gen xiong Ze Zhang Xiao-Yun Huang Yan Huang Ji Yu Jian-Xin Cai Zhen-Yu Yang College of Chemistry Key laboratory of Jiangxi Province for Environment and Energy CatalysisNanchang UniversityNanchang 330031 JiangxiChina

Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of ***, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).

关键词： Lithium–sulfur batteries Porous carbon nanosheets B/N–codoped Lewis acid–base Bimodal–pore structure

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Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： dong WANG Jing YANG Kai xiong School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty and unknown time-varying system noise hinder the filtering accuracy of the autonomous navigation system of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employed to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency *** that the number of available measurements varies online with intersatellite visibility in practical applications such as time-varying constellation configurations,the smooth covariance matrix of state correction determined by innovation and gain is adopted and constructed *** analysis of the proposed method is also *** effectiveness of the proposed method is verified by the Monte Carlo simulation and comparison *** estimation accuracy of constellation position and velocity of UKF-AFF is improved by 30%and 44%respectively compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability analysis

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Algorithmic approach to discrete fracture network flow modeling in consideration of realistic connections in large-scale fracture networks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3798-3811页

作者： Qihua Zhang Shan dong Yaoqi Liu Junjie Huang Feng xiong Badong National Observation and Research Station of Geohazards China University of GeosciencesWuhan430074China SINOPEC Shanghai Engineering Co. Ltd.Shanghai200120China Faculty of Engineering China University of GeosciencesWuhan430074China

Analyzing rock mass seepage using the discrete fracture network(DFN)flow model poses challenges when dealing with complex fracture *** paper presents a novel DFN flow model that incorporates the actual connections of large-scale ***,this model efficiently manages over 20,000 fractures without necessitating adjustments to the DFN *** geometric analyses,such as identifying connected fractures,dividing the two-dimensional domain into closed loops,triangulating arbitrary loops,and refining triangular elements,are fully *** analysis processes are comprehensively introduced,and core algorithms,along with their pseudo-codes,are outlined and explained to assist readers in their programming *** accuracy of geometric analyses is validated through topological graphs representing the connection relationships between *** practical application,the proposed model is employed to assess the water-sealing effectiveness of an underground storage cavern *** analysis results indicate that the existing design scheme can effectively prevent the stored oil from leaking in the presence of both dense and sparse ***,following extensive modification and optimization,the scale and precision of model computation suggest that the proposed model and developed codes can meet the requirements of engineering applications.

关键词： Discrete fracture network(DFN)flow model Geometric algorithm Fracture flow Water-sealing effect

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A survey on the network models applied in the industrial network optimization

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Science China(Information Sciences) 2024年第2期67卷 85-103页

作者： Chao dong Xiaoxiong xiong Qiulin XUE Zhengzhen ZHANG Kai NIU Ping ZHANG Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Smart City College Beijing Union University

Network architecture design is critical for optimizing industrial networks. Network architectures can be classified into small-scale networks and large-scale networks based on scale. Graph theory is an efficient mathematical tool for network topology modeling. For small-scale networks, their structure often has regular topology. For large-scale ones, the current body of work mainly focuses on random characteristics of network nodes and edges. Recently, widely used models include random networks, small-world networks,and scale-free networks. In this study, starting from the scale of the network, network modeling methods based on graph theory as well as their industrial applications, are summarized and analyzed. Moreover, a novel network performance metric, called system entropy, is proposed. From the perspective of mathematical properties, an analysis of its non-negativity and concavity is performed. The advantage of system entropy is that it can cover the existing regular networks, random networks, small-world networks, and scale-free networks, and has strong generality. The simulation results reveal that this proposed metric can achieve the comparison of various industrial networks under different models.

关键词： industrial network small-scale network large-scale network graph theory system entropy

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Homochirality in Ferroelectrochemistry

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Chinese Journal of Chemistry 2024年第10期42卷 1133-1144页

作者： Hang Peng Jun-Chao Qi Yu-Si Liu Jia-Mei Zhang Wei-Qiang Liao Ren-gen xiong Ordered Matter Science Research Center Nanchang UniversityNanchangJiangxi 330031China

What is the most favorite and original chemistry developed in your research group?We originally proposed the design principle for molecular ferroelectrics:ferroelectrochemistry,including quasi-spherical theory,the introduction of homochirality,and H/F *** changed the blind search for molecular ferroelectrics into targeted chemical design,which will develop into a new discipline.

关键词： Molecular ferroelectrics Homochirality Ferroelectricity Chemical design Point groups

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Mitigation of Deane and Hamill phenomenon in gallium nitride high-voltage power supply for electric propulsion system application

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High Voltage 2024年第1期9卷 252-265页

作者： Minghai dong Hui Li Shan Yin Kye Yak See Yingzhe Wu xiong Xin School of Aeronautics&Astronautics University of Electronic Science and Technology of ChinaChengduChina School of Electrical&Electronic Engineering Nanyang Technological UniversitySingaporeSingapore School of Automation Engineering University of Electronic Science and Technology of ChinaChengduChina Innoscience(Shenzhen)Semiconductor Co.Ltd. ShenzhenChina

The step-up resonant converters are widely adopted to provide high voltage in kV-level for electric propulsion system due to their high efficiency,low mass,modularisation,and high-power *** bipolar Cockcroft-Walton voltage multiplier(BiCWVM)is a major circuit that steps up the voltage in the resonant ***,the diode nonlinearity in BiCWVM can introduce self-sustained quasi-periodic oscillations in the voltage and current waveforms,which is commonly known as the Deane and Hamill(DH)*** oscillation can lead to higher magnetic loss and control failure,and it is more likely to present in the gallium nitride-based converter due to the highfrequency *** authors aim to investigate and mitigate the DH phenomenon systematically so that proper mitigation can be *** facilitate the investigation,the circuit before the BiCWVM in the converter is derived and modelled as a voltage source v_(m)and a series inductor L_(sy).Also,the reverse recovery process of the diode in the BiCWVM can be represented by a piecewise-linear(PWL)model,with the simplified circuit and PWL model,the relationship between voltage and current under different operating conditions can be determined with *** relationship allows to understand the mechanism of diode reverse recovery in BiCWVM that leads to DH ***,a hybrid-/full-silicon carbide(SiC)design is proposed to mitigate the DH phenomenon,which is verified experimentally for a 300-kHz,5-W,20-V/1.5-kV GaN-based step-up resonant converter.

关键词： power resonant high

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Efficient concentration of trace analyte with ordered hotspot construction for a robust and sensitive SERS platform

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International Journal of Extreme Manufacturing 2024年第3期6卷 532-542页

作者： Youdi Hu Yanlei Hu Zhenyu Wang Jiale Yong Wei xiong dong Wu Shixiang Xu Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenGuangdong 518060People’s Republic of China CAS Key Laboratory of Mechanical Behavior and Design of Materials Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education InstitutesDepartment of Precision Machinery and Precision InstrumentationUniversity of Science and Technology of ChinaHefeiAnhui 230027People’s Republic of China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhanHubeiPeople’s Republic of China

Surface-enhanced Raman scattering(SERS)platform,which enables trace analyte detection,has important application *** structuring/modifying the surface of the SERSsubstrate,analyte in highly diluted solutions can be concentrated into localized active areas for highly sensitive ***,subject to the difficulty of the fabrication process,itremains challenging to balance hot-spot construction and the concentration capacity of analyte ***,preparing SERS substrates with densely ordered hot spots andefficient concentration capacity is of great significance for highly sensitive ***,we propose an Ag and fluoroalkyl-modified hierarchical armour substrate(Ag/F-HA),which has a double-layer stacking design to combine analyte concentration with hotspot *** microarmour structure is fabricated by femtosecond-laser processing to serve as asuperhydrophobic and low-adhesive surface to concentrate analyte,while the anodic aluminium oxide(AAO)template creates a nanopillar array serving as dense and ordered hot *** the synergistic action of hot spots and analyte concentration,Ag/F-HA achieves a detectionlimit down to 10^(-7)M doxorubicin(DOX)molecules with a RSD of 7.69%.Additionally,Ag/F-HA exhibits excellent robustness to resist external disturbances such as liquid splash or *** on our strategy,SERS substrates with directional analyte concentrations are further explored by patterning microcone arrays with *** work opens a way to the realistic implementation of SERS in diverse scenarios.

关键词： surface-enhanced Raman scattering anodic aluminium oxide femtosecond laser processing concentration of trace analytes mechanical robustness

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An intelligent active probing and trace-back scheme for IoT anomaly detection

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Digital Communications and Networks 2024年第1期10卷 168-181页

作者： Luying Wang Lingyi Chen Neal N.xiong Anfeng Liu Tian Wang Mianxiong dong School of Computer Science and Engineering Central South UniversityChangsha 410083China Department of Computer Science and Mathematics Sul Ross State UniversityAlpineTX 79830USA Artificial Intelligence and Future Networks Beijing Normal University&UICZhuhai 519087China Department of Information and Electronic Engineering Muroran Institute of TechnologyMuroran 050-8585Japan

Due to their simple hardware,sensor nodes in IoT are vulnerable to attack,leading to data routing blockages or malicious tampering,which significantly disrupts secure data *** Intelligent Active Probing and Trace-back Scheme for IoT Anomaly Detection(APTAD)is proposed to collect integrated IoT data by recruiting Mobile Edge Users(MEUs).(a)An intelligent unsupervised learning approach is used to identify anomalous data from the collected data by MEUs and help to identify anomalous nodes.(b)Recruit MEUs to trace back and propose a series of trust calculation methods to determine the trust of nodes.(c)The last,the number of active detection packets and detection paths are designed,so as to accurately identify the trust of nodes in IoT at the minimum cost of the network.A large number of experimental results show that the recruiting cost and average anomaly detection time are reduced by 6.5 times and 34.33%respectively,while the accuracy of trust identification is improved by 20%.

关键词： Anomaly detection Internet of things Integrating data collection Mobile edge users Intelligent

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Age of Information Based User Scheduling and Data Assignment in Multi-User Mobile Edge Computing Networks:An Online Algorithm

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China Communications 2024年第5期21卷 153-165页

作者： Ge Yiyang xiong Ke dong Rui Lu Yang Fan Pingyi Qu Gang School of Computer and Information Technology Beijing Jiaotong UniversityBeijing 100044China Engineering Research Center of Network Management Technology for High Speed Railway of Ministry of Education Beijing 100044China Beijing Engineering Research Center of High-speed Railway Broadband Mobile Communications Beijing 100044China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Department of Electrical and Computer Engineering College ParkMarylandUSA

This paper investigates the age of information(AoI)-based multi-user mobile edge computing(MEC)network with partial offloading *** weighted sum AoI(WSA)is first analyzed and derived,and then a WSA minimization problem is formulated by jointly optimizing the user scheduling and data *** to the non-analytic expression of the WSA *** optimization variables and the unknowability of future network information,the problem cannot be solved with known solution ***,an online Joint Partial Offloading and User Scheduling Optimization(JPOUSO)algorithm is proposed by transforming the original problem into a single-slot data assignment subproblem and a single-slot user scheduling sub-problem and solving the two sub-problems *** analyze the computational complexity of the presented JPO-USO algorithm,which is of O(N),with N being the number of *** results show that the proposed JPO-USO algorithm is able to achieve better AoI performance compared with various baseline *** is shown that both the user’s data assignment and the user’s AoI should be jointly taken into account to decrease the system WSA when scheduling users.

关键词： age of information(aoi) mobile edge computing(mec) user scheduling

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DMPP mitigates N_(2)O and NO productions by inhibiting ammonia-oxidizing bacteria in an intensified vegetable field under different temperature and moisture regimes

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Pedosphere 2024年第3期34卷 652-663页

作者： Xi ZHANG Xintong XU Chenyuan WANG Qianqian ZHANG Yubing dong Zhengqin xiong Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095(China) Department of Soil Science of Temperate Ecosystems Department of Agricultural Soil ScienceGeorg-August University of GottingenGottingen 37077(Germany) State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou 311300(China) Huaiyin Institute of Agricultural Sciences of Xuhuai Region in Jiangsu Jiangsu Academy of Agricultural SciencesHuai’an 223001(China)

Vegetable soils with high nitrogen input are major sources of nitrous oxide(N_(2)O)and nitric oxide(NO),and incorporation of the nitrification inhibitor 3,4-dimethylpyrazole phosphate(DMPP)into soils has been documented to effectively reduce ***,the efficiency of DMPP in terms of soil N_(2)O and NO mitigations varies greatly depending on soil temperature and moisture ***,further evaluations of DMPP efficiency in diverse environments are required to encourage widespread application.A laboratory incubation study(28 d)was established to investigate the interactive effects of DMPP,temperature(15,25,and 35?C),and soil moisture(55% and 80% of water-holding capacity(WHC))on net nitrification rate,N_(2)O and NO productions,and gene abundances of nitrifiers and denitrifiers in an intensive vegetable *** showed that incubating soil with 1%DMPP led to partial inhibition of the net nitrification rate and N_(2)O and NO productions,and the reduction percentage of N_(2)O production was higher than that of NO production(69.3%vs.38.2%)regardless of temperature and soil moisture *** increased temperatures promoted the net nitrification rate but decreased soil N_(2)O and NO *** moisture influenced NO production more than N_(2)O production,decreasing with the increased moisture level(80%).The inhibitory effect of DMPP on cumulative N_(2)O and NO productions decreased with increased temperatures at 55%***,the inhibitory effect of DMPP on cumulative N_(2)O production increased with increased temperatures at 80%*** on the correlation analyses and automatic linear modeling,the mitigation of both N_(2)O and NO productions from the soil induced by DMPP was attributed to the decreases in ammonia-oxidizing bacteria(AOB)amoA gene abundance and NO_(2)^(-)-N ***,our study indicated that DMPP reduced both N_(2)O and NO productions by regulating the associated AOB amoA gene abundance and NO_(2)^(-)-N concentra

关键词： 3,4-dimethylpyrazole phosphate environment condition gene abundance nitrification inhibitor nitrite accumulation soil water content

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