检索结果-南通市图书馆

Game-theoretical Model for dynamic defense Resource Allocation in Cyber-physical Power Systems Under distributed denial of Service Attacks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 41-51页

作者： Bingjing Yan Pengchao Yao Tao Yang Boyang Zhou Qiang Yang the College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Zhejiang lab Hangzhou 311100China

Electric power grids are evolving into complex cyber-physical power systems(CPPSs)that integrate advanced information and communication technologies(ICTs)but face increasing cyberspace threats and attacks.This study considers CPPS cyberspace security under distributed denial of service(ddoS)attacks and proposes a nonzero-sum game-theoretical model with incomplete information for appropriate allocation of defense resources based on the availability of limited resources.Task time delay is applied to quantify the expected utility as CPPSs have high time requirements and incur massive damage ddoS attacks.different resource allocation strategies are adopted by attackers and defenders under the three cases of attack-free,failed attack,and successful attack,which lead to a corresponding consumption of resources.A multidimensional node value analysis is designed to introduce physical and cybersecurity indices.Simulation experiments and numerical results demonstrate the effectiveness of the proposed model for the appropriate allocation of defense resources in CPPSs under limited resource availability.

关键词： Game theory complex cyber-physical power system(CPPS) multidimensional evaluation distributed denial of service(ddoS)attack

Intrinsic pentagon defect engineering in multiple spatial-scale carbon frameworks for efficient triiodide reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第8期95卷 20-28页

作者： Siyi Hou Xuedan Song Chang Yu Jiangwei Chang Yiwang ding Yingbin Liu Xiubo Zhang Weizhe Liu Jieshan Qiu State Key lab of Fine Chemicals Liaoning Key Lab for Energy Materials and Chemical Engineering Frontier Science Center for Smart Materials School of Chemical EngineeringDalian University of Technology Liaoning Key lab for Energy Materials and Chemical Engineering Frontier Science Center for Smart Materials School of Chemistry Dalian University of Technology State Key laboratory of Chemical Resource Engineering College of Chemical Engineering Beijing University of Chemical Technology

Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials. However, the controllable construction of high-density and specific topological defects in carbon frameworks to reveal the relationship between reactivity and defect structure remains a challenging task. Herein, the intrinsic pentagon carbon sites that can favor electron overflow and enhance their binding affinity towards the intermediates of catalytic reaction are firstly presented by the work function and the p-band center calculations. To experimentally verify this, the cage-opening reaction of fullerene is proposed and utilized for synthesizing carbon quantum dots with specific pentagon configuration(CQds-P), subsequently utilizing CQds-P to modulate the micro-scale defect density of three-dimensional reduced graphene oxide(rGO) via π-π interactions. The multiple spatial-scale rGO-conjugated CQds-P structure simultaneously possesses abundant pentagon and edge defects as catalytic active sites and long-range-ordered π electron delocalization system as conductive network. The defects-rich CQds-P/rGO-4 all-carbon-based catalyst exhibits superb catalytic activity for triiodide reduction reaction with a high photoelectric conversion efficiency of 8.40%, superior to the Pt reference(7.97%). Theoretical calculations suggest that pentagon defects in the carbon frameworks can promote charge transfer and modulate the adsorption/dissociation behavior of the reaction intermediates, thus enhancing the electrocatalytic activity of the catalyst. This work confirms the role of intrinsic pentagon defects in catalytic reactions and provides a new insight into the synthesis of defects-rich carbon catalysts.

关键词： Carbon quantum dots defect engineering Electrocatalytic activity Pentagon carbon Triiodide reduction

Modified electronic structure and enhanced hydroxyl adsorption make quaternary Pt-based nanosheets efficient anode electrocatalysts for formic acid-/alcohol-air fuel cells

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第5期92卷 142-150页

作者： Fengling Zhao Qiang Yuan Siyang Nie Liang Wu Xun Wang State-Local Joint laboratory for Comprehensive Utilization of Biomass Center for R&D of Fine ChemicalsCollege of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025GuizhouChina Key lab of Organic Optoelectronics&Molecular Engineering Tsinghua UniversityBeijing 100084China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Surface/interface engineering of a multimetallic nanostructure with diverse electrocatalytic properties for direct liquid fuel cells is desirable yet challenging.Herein,using visible light,a class of quaternary Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)ultrathin nanosheets is fabricated and used as high-performance anode electrocatalysts for formic acid-/alcohol-air fuel cells.The modified electronic structure of Pt,enhanced hydroxyl adsorption,and abundant exterior defects afford Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C high intrinsic anodic electrocatalytic activity to boost the power densities of direct formic acid-/methanol-/ethanol-/ethylene glycol-/glycerol-air fuel cells,and the corresponding peak power density of Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C is respectively 129.7,142.3,105.4,124.3,and 128.0 mW cm^(-2),considerably outperforming Pt/C.Operando in situ Fourier transform infrared reflection spectroscopy reveals that formic acid oxidation on Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C occurs via a CO_(2)-free direct pathway.density functional theory calculations show that the presence of Ag,Bi,and Te in Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)suppresses CO^(*)formation while optimizing dehydrogenation steps and synergistic effect and modified Pt effectively enhance H_(2)O dissociation to improve electrocatalytic performance.This synthesis strategy can be extended to 43 other types of ultrathin multimetallic nanosheets(from ternary to octonary nanosheets),and efficiently capture precious metals(i.e.,Pd,Pt,Rh,Ru,Au,and Ag)from different water sources.

关键词： Pt-based nanosheets Modifiedelectronic structure Enhanced hydroxyl adsorption Formicacidand alcohol oxidation direct liquid fuel cells

Advancements,strategies,and prospects of solid oxide electrolysis cells(SOECs):Towards enhanced performance and large-scale sustainable hydrogen production

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第7期94卷 688-715页

作者： Amina Lahrichi Youness El Issmaeli Shankara S.Kalanur Bruno G.Pollet Green Hydrogen lab(GH2lab) Hydrogen Research Institute(HRI)Universitédu QuébecàTrois-Rivières(UQTR)3351 boulevard des ForgesTrois-RivièresQuébec G9A 5H7Canada

Solid oxide electrolysis cells(SOECs)represent a crucial stride toward sustainable hydrogen generation,and this review explores their current scientific challenges,significant advancements,and potential for large-scale hydrogen production.In SOEC technology,the application of innovative fabrication tech-niques,doping strategies,and advanced materials has enhanced the performance and durability of these systems,although degradation challenges persist,implicating the prime focus for future advancements.Here we provide in-depth analysis of the recent developments in SOEC technology,including Oxygen-SOECs,Proton-SOECs,and Hybrid-SOECs.Specifically,Hybrid-SOECs,with their mixed ionic conducting electrolytes,demonstrate superior efficiency and the concurrent production of hydrogen and oxygen.Coupled with the capacity to harness waste heat,these advancements in SOEC technology present signif-icant promise for pilot-scale applications in industries.The review also highlights remarkable achieve-ments and potential reductions in capital expenditure for future SOEC systems,while elaborating on the micro and macro aspects of sOECs with an emphasis on ongoing research for optimization and scal-ability.It concludes with the potential of SOEC technology to meet various industrial energy needs and its significant contribution considering the key research priorities to tackle the global energy demands,ful-fillment,and decarbonization efforts.

关键词： Solid oxide electrolysis cells Proton-SOECs Oxygen-SoECs Hybrid-SOECs Intermediate-high temperature electrolysers Hydrogenproduction

Grain size refinement of additive manufactured Ce-TZP ceramics by coupled two-step pre-sintering and HIP

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第5期13卷 621-629页

作者： Ruoshi Zhao Hongbing Yang Xintong Liu Hezhen Li Chang-An Wang Jing Ma Yanhao dong State Key lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Ceria-stabilized tetragonal zirconia polycrystal(Ce-TZP)has exceptional fracture toughness and flaw tolerance due to facile t‒m phase transformation toughening.However,its wider-range applications are limited by its relatively low strength due to its large grain size and low transformation stress,which results in yield-like failure.Here,we combined additive manufacturing(AM),pressureless two-step sintering,and hot isostatic pressing(HIP),and addressed the challenging grain size refinement problem in Ce-TZPs.We successfully produced dense ultrafine-grained Ce-TZP ceramics with an average grain size below 500 nm,a three-point bending strength above 800 MPa,and a single-edge-notch-beam fracture toughness in the range of 11‒12 MPa·m^(1/2).The critical roles of processing design,mixed Ce valences,and under-vs.over-stabilization of tetragonal polymorphs were noted.Our work offers insights and strategies for the future development of stronger and tougher Ce-TZP ceramics that can compete with tetragonal yttria-stabilized zirconia in various applications,including additive manufacturing.

关键词： zirconia additive manufacturing(AM) two-step sintering hot isostatic pressing(HIP) grain size refinement

Sex differences in Alzheimer's disease:an urgent research venue to follow

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第12期19卷 2569-2570页

作者： Raquel Jiménez-Herrera Ana Contreras Juan d.Navarro-López Lydia Jiménez-díaz Neurophysiology&Behavior lab University of Castilla-La ManchaSchool of Medicine of Ciudad RealCiudad RealSpain

due to increasing life expectancy,the amount of people with dementia worldwide is expected to experience a substantial rise,with estimates indicating a growth from 55 million in 2019 to a staggering 139 million by the year 2050.Among the various forms of dementia.Alzheimer's disease(Ad)stands out as the predominant and most prevalent.

关键词： Alzheimer predominant estimates

Full-Scale Isogeometric Topology Optimization of Cellular Structures Based on Kirchhoff-Love Shells

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第6期139卷 2479-2505页

作者： Mingzhe Huang Mi Xiao Liang Gao Mian Zhou Wei Sha Jinhao Zhang State Key lab of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China

Cellular thin-shell structures are widely applied in ultralightweight designs due to their high bearing capacity and strength-to-weight ratio.In this paper,a full-scale isogeometric topology optimization(ITO)method based on Kirchhoff-Love shells for designing cellular tshin-shell structures with excellent damage tolerance ability is proposed.This method utilizes high-order continuous nonuniform rational B-splines(NURBS)as basis functions for Kirchhoff-Love shell elements.The geometric and analysis models of thin shells are unified by isogeometric analysis(IGA)to avoid geometric approximation error and improve computational accuracy.The topological configurations of thin-shell structures are described by constructing the effective density field on the controlmesh.Local volume constraints are imposed in the proximity of each control point to obtain bone-like cellular structures.To facilitate numerical implementation,the p-norm function is used to aggregate local volume constraints into an equivalent global constraint.Several numerical examples are provided to demonstrate the effectiveness of the proposed method.After simulation and comparative analysis,the results indicate that the cellular thin-shell structures optimized by the proposed method exhibit great load-carrying behavior and high damage robustness.

关键词： Cellular thin-shell structures isogeometric analysis full-scale topology optimization Kirchhoff–Love shells

Cooperative User-Scheduling and Resource Allocation Optimization for Intelligent Reflecting Surface Enhanced LEO Satellite Communication

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2024年第2期21卷 227-244页

作者： Meng Meng Bo Hu Shanzhi Chen Jianyin Zhang State Key lab of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China State Key lab of Wireless Mobile Communication China Academy of Telecommunication TechnologyBeijing 100191China Research Institute of China Mobile Beijing 100053China

Lower Earth Orbit(LEO) satellite becomes an important part of complementing terrestrial communication due to its lower orbital altitude and smaller propagation delay than Geostationary satellite. However, the LEO satellite communication system cannot meet the requirements of users when the satellite-terrestrial link is blocked by obstacles. To solve this problem, we introduce Intelligent reflect surface(IRS) for improving the achievable rate of terrestrial users in LEO satellite communication. We investigated joint IRS scheduling, user scheduling, power and bandwidth allocation(JIRPB) optimization algorithm for improving LEO satellite system throughput.The optimization problem of joint user scheduling and resource allocation is formulated as a non-convex optimization problem. To cope with this problem, the nonconvex optimization problem is divided into resource allocation optimization sub-problem and scheduling optimization sub-problem firstly. Second, we optimize the resource allocation sub-problem via alternating direction multiplier method(AdMM) and scheduling sub-problem via Lagrangian dual method repeatedly.Third, we prove that the proposed resource allocation algorithm based AdMM approaches sublinear convergence theoretically. Finally, we demonstrate that the proposed JIRPB optimization algorithm improves the LEO satellite communication system throughput.

关键词： convex optimization intelligent reflecting surface LEO satellite communication OFdM

Improving creep strength of the fine-grained heat-affected zone of novel 9Cr martensitic heat-resistant steel via modified thermo-mechanical treatment

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1037-1047页

作者： Jingwen Zhang Liming Yu Yongchang Liu Ran ding Chenxi Liu Zongqing Ma Huijun Li Qiuzhi Gao Hui Wang State Key lab of Hydraulic Engineering Simulation and Safety Tianjin Key Lab of Composite and Functional MaterialsTianjin UniversityTianjin 300072China School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional thermo-mechanical treatment was modified via the replacement of hot-rolling with cold rolling,i.e.,normalizing,cold rolling,and tempering (NCT),which was developed to improve the creep strength of the FGHAZ in G115 steel weldments.The NCT treatment effectively promoted the dissolution of preformed M_(23)C_(6)particles and relieved the boundary segregation of C and Cr during welding thermal cycling,which accelerated the dispersed reprecipitation of M_(23)C_(6) particles within the fresh reaustenitized grains during post-weld heat treatment.In addition,the precipitation of Cu-rich phases and MX particles was promoted evidently due to the deformation-induced dislocations.As a result,the interacting actions between precipitates,dislocations,and boundaries during creep were reinforced considerably.Following this strategy,the creep rupture life of the FGHAZ in G115 steel weldments can be prolonged by 18.6%,which can further push the application of G115 steel in USC power plants.

关键词： G115 steel fine-grained heat-affected zone creep strength element segregation nano-sized precipitates