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A fast forward computational method for nuclear measurement using volumetric detection constraints

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Nuclear Science and Techniques 2024年第2期35卷 47-63页

作者： qiong zhang Lin-Lv Lin University of Electronic Science and Technology of China Chengdu 610000China

Owing to the complex lithology of unconventional reservoirs,field interpreters usually need to provide a basis for interpretation using logging simulation *** the various detection tools that use nuclear sources,the detector response can reflect various types of information of the *** Monte Carlo method is one of the primary methods used to obtain nuclear detection responses in complex ***,this requires a computational process with extensive random sampling,consumes considerable resources,and does not provide real-time response ***,a novel fast forward computational method(FFCM)for nuclear measurement that uses volumetric detection constraints to rapidly calculate the detector response in various complex environments is ***,the data library required for the FFCM is built by collecting the detection volume,detector counts,and flux sensitivity functions through a Monte Carlo ***,based on perturbation theory and the Rytov approximation,a model for the detector response is derived using the flux sensitivity function method and a one-group diffusion *** environmental perturbation is constrained to optimize the model according to the tool structure and the impact of the formation and borehole within the effective detection ***,the method is applied to a neutron porosity tool for *** various complex simulation environments,the maximum relative error between the calculated porosity results of Monte Carlo and FFCM was 6.80%,with a rootmean-square error of 0.62 *** field well applications,the formation porosity model obtained using FFCM was in good agreement with the model obtained by interpreters,which demonstrates the validity and accuracy of the proposed method.

关键词： Nuclear measurement Fast forward computation Volumetric constraints

Review on Security Defense Technology Research in Edge Computing Environment

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Chinese Journal of Electronics 2024年第1期33卷 1-18页

作者： ke SHANG Weizhen HE Shuai zhang National Digital Switching System Engineering and Technological R&D Center

Edge computing, which achieves quick data processing by sinking data computing and storage to the network edge, has grown rapidly along with the Internet of things. The new network architecture of edge computing brings new security challenges. Based on this, this paper investigates the edge computing security literature published in recent years and summarizes and analyzes research work on edge computing security from different attack surfaces. We start with the definition and architecture of edge computing. From the attack surface between device and edge server, as well as on edge servers, the research describes the security threats and defense methods of edge computing. In addition, the cause of the attack and the pros and cons of defense methods is introduced. The challenges and future research directions of edge computing are given.

关键词： Cloud computing Systems architecture Computer architecture Network architecture Data processing Security Servers

Strong Edge Coloring of Outerplane Graphs with Independent Crossings

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 467-477页

作者： ke-Jie LI Xin zhang School of Mathematics and Statistics Xidian UniversityXi’an 710071China

The strong chromatic index of a graph is the minimum number of colors needed in a proper edge coloring so that no edge is adjacent to two edges of the same *** outerplane graph with independent crossings is a graph embedded in the plane in such a way that all vertices are on the outer face and two pairs of crossing edges share no common end *** is proved that every outerplane graph with independent crossings and maximum degreeΔhas strong chromatic index at most 4Δ-6 if Δ≥4,and at most 8 ifΔ≤*** bounds are sharp.

关键词： outer-1-planar graph IC-planar graph strong edge coloring crossing

Incidence Coloring of Outer-1-planar Graphs

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 840-848页

作者： Meng-ke QI Xin zhang School of Mathematics and Statistics Xidian UniversityXi'an 710071China

A graph is outer-1-planar if it can be drawn in the plane so that all vertices lie on the outer-face and each edge crosses at most one another *** is known that every outer-1-planar graph is a planar *** this paper,we conjecture that every planar graph G has a proper incidence(Δ(G)+2)-coloring and confirm it for outer-1-planar graphs with maximum degree at least 8 or with girth at least ***,we prove that every outer-1-planar graph G has an incidence(Δ(G)+3,2)-coloring,and every outer-1-planar graph G with maximum degree at least 8 or with girth at least 4 has an incidence(Δ(G)+2,2)-coloring.

关键词： incidence coloring outer--planar graph planar graph

Highly cycle-stable VOPO_(4)-based cathodes for magnesium ion batteries:Insight into the role of interlayer engineering in batteries performance

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Nano Research 2024年第7期17卷 6127-6138页

作者： Jiahe zhang Jing Shang Xiaojun zhang ke Wang Yihe zhang Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid WastesNational Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of Geosciences(Beijing)Beijing 100083China

It is the sluggish ion migration kinetics that seriously affects the practical performance of the magnesium ion *** though an electrode material design using rational interlayer engineering method could effectively solve this issue,the optimal interlayer distance remains ***,various VOPO_(4)-based electrodes with expanded interlayer spacing were fabricated and the relationship between interlayer structure and battery performance was *** analysis combined with computations unveils the existence of an optimal interlayer structure,as inadequate expansion failed to fully utilization of the material performance,while excessive expansion degraded the electrode *** them,the electrode with triethylene glycol(TEG)intercalation exhibited optimized performance,maintaining excellent cycling stability(191.3 mAh·g^(−1)after 800 cycles).Density functional theory(DFT)demonstrated the effectiveness and limitations to lowering the migration energy barrier by expanding the interlayer *** addition,systematic mechanism research revealed the Mg^(2+)storage process:The stepwise shuttling of Mg^(2+)along the directions that lie in(001)plane triggers two pairs of redox processes,namely V^(5+)/V^(4+)and V^(4+)/V^(3+).This study,regulation of layer spacing to achieve the best integrated performance of electrodes,could deepen the understanding of interlayer engineering and guide the design of advanced multivalent-ion batteries.

关键词： magnesium ion batteries layered electrodes interlayer engineering energy storage mechanisms high kinetics

Regulating^(*)COOH intermediate via amino alkylation engineering for exceptionally effective photocatalytic CO_(2) reduction

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Journal of Energy Chemistry 2024年第5期92卷 282-291页

作者： Chengcheng Chen Qiaoyu zhang Fangting Liu Zhengguo zhang qiong Liu Xiaoming Fang key Laboratory of Enhanced Heat Transfer and Energy Conservation The Ministry of EducationSchool of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640GuangdongChina Guangdong Provincial key Laboratory of Chemical Measurement and Emergency Test Technology(China) Institute of AnalysisGuangdong Academy of Sciences(China National Analytical CenterGuangzhou)Guangzhou 510070GuangdongChina Guangdong Engineering Technology Research Center of Efficient Heat Storage and Application South China University of TechnologyGuangzhou 510640GuangdongChina Guangdong Provincial key Laboratory of Fuel Cell Technology South China University of TechnologyGuangzhou 510640GuangdongChina

Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target *** the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant *** this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) *** characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic ***,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%.

关键词： Polymeric carbonnitride Regulate intermediate Photocatalytic CO_(2)reduction Amino alkylation ^(*)COOH adsorption

Integration of urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays within porous copper current collector for superior performance Li-ion battery anodes

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Rare Metals 2024年第2期43卷 599-611页

作者： Xue-Ru zhang qiong Wu Yong zhang Xi-Fei Li Ting Xie Yu-Cheng Wu Instrumental Analysis Center Hefei University of TechnologyHefei230009China key Laboratory of Advanced Functional Materials and Devices of Anhui Province Hefei230009China School of Materials Science and Engineering Hefei University of TechnologyHefei230009China Institute of Advanced Electrochemical Energy Xi’an University of TechnologyXi’an710048China

Spinel MnCo_(2)O_(4) is a promising energy storage candidate as anode materials in lithium-ion batteries owing to synergistic effects of two intrinsic solid-state redox ***,low conductivity,poor rate capacity and rapid capacity fading have seriously impaired its practical *** overcome the inferiorities,urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays have been fabricated directly within a porous copper current collector via a facile hydrothermal method followed by a chemical vapor deposition carbonization *** a typical nanowire,the core is composed of interconnected MnCo_(2)O_(4)nanoparticles and the shell shows as a thin amorphous carbon *** integrated MnCo_(2)O_(4)@C/Cu structure could act as working anodes without using additives or polymer *** MnCo_(2)O_(4)@C/Cu possesses slightly longer Li-ion insertion/desertion pathway than that of MnCo_(2)O_(4)/Cu,the carbon shell could effectively prevent the pulverization of MnCo_(2)O_(4) and lower down charge transfer resistance and actively participate in Li-ion *** rearrangement of carbon atoms during lithiation/delithiation cycling could inhibit the formation of passive solid electrolyte interphase *** a result,the MnCo_(2)O_(4)@C/Cu electrode presents superior rate capacity(600 mAh·g^(−1) at 1 A·g^(−1)) and better stability(797 mAh·g^(−1) after 200 cycles at 100 mA·g^(−1)).The excellent reversible Li ion storage capacity,cycling stability and rate capacity endow MnCo_(2)O_(4)@C/Cu great potential as stable and high output integrated anode materials in Li-ion batteries.

关键词： MnCo_(2)O_(4)@C Urchin-like nanowire arrays Core-shell Integrated anode materials Lithium-ion batteries

Current optimization-based control of dual three-phase PMSM for low-frequency temperature swing reduction

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Defence Technology（防务技术） 2024年第4期34卷 238-246页

作者： Linlin Lu Xueqing Wang Luhan Jin qiong Liu Yun zhang Yao Mao key Laboratory of Optical Engineering Chinese Academy of SciencesChengdu 610209China Institute of Optics and Electronics Chinese Academy of SciencesChengdu 610209China University of Chinese Academy of Sciences Beijing 100049China College of Electrical Engineering Sichuan UniversityChengdu 610065China

In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature *** reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this ***,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is ***,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy *** that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total *** this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.

关键词： Dual three-phase PMSM Low-frequency temperature swing Copper loss Current optimization Connected neutral points

Hybrid Dynamic Variables-Dependent Event-Triggered Fuzzy Model Predictive Control

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 723-733页

作者： Xiongbo Wan Chaoling zhang Fan Wei Chuan-ke zhang Min Wu IEEE the School of Automation China University of Geosciencesthe Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systemsand the Engineering Research Center of Intelligent Technology for Geo-ExplorationMinistry of EducationWuhan 430074China

This article focuses on dynamic event-triggered mechanism(DETM)-based model predictive control(MPC) for T-S fuzzy systems.A hybrid dynamic variables-dependent DETM is carefully devised,which includes a multiplicative dynamic variable and an additive dynamic *** addressed DETM-based fuzzy MPC issue is described as a “min-max” optimization problem(OP).To facilitate the co-design of the MPC controller and the weighting matrix of the DETM,an auxiliary OP is proposed based on a new Lyapunov function and a new robust positive invariant(RPI) set that contain the membership functions and the hybrid dynamic variables.A dynamic event-triggered fuzzy MPC algorithm is developed accordingly,whose recursive feasibility is analysed by employing the RPI *** the designed controller,the involved fuzzy system is ensured to be asymptotically *** examples show that the new DETM and DETM-based MPC algorithm have the advantages of reducing resource consumption while yielding the anticipated performance.

关键词： Dynamic event-triggered mechanism(DETM) hybrid dynamic variables model predictive control(MPC) robust positive invariant(RPI)set T-S fuzzy systems