检索结果-南通市图书馆

Influences of chemical reactions on polysulfide reduction reaction process on promotor surface in Li-S batteries

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 2712-2718页

作者： Yufeng Luo Zhenhan Fang Zixin Hong Shaorong duan Haitao Liu Hengcai Wu Qunqing Li Yuegang Zhang Shoushan Fan Wenhui duan Jiaping Wang Tsinghua-Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing 100084China Department of Physics Tsinghua UniversityBeijing 100084China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Frontier Science Center for Quantum Information Tsinghua UniversityBeijing 100084China

Polar promotors have been proven effective in catalyzing the polysulfide(PS)reduction reaction(PSRR)process in lithium-sulfur(Li-S)***,the promotor surface tends to be poisoned due to the accumulation of insoluble discharging products of lithium disulfide(Li_(2)S_(2))and lithium sulfide(Li_(2)S)during Li-S battery ***,we investigate the detailed PSRR mechanism on the surface of manganese sulfides(MnS)as a representative promoter by performing in-situ Raman mapping *** catalytic ability of MnS enables thorough electrochemical reduction of PSs to Li_(2)S_(2) and Li_(2)S on the MnS *** generated Li_(2)S_(2) and Li_(2)S then adsorb the dissolved PSs via chemical reactions among sulfur species during the subsequent PSRR *** phenomenon mitigates promotor poisoning and continuously improves the reversible ***,the assembled Li-S cell demonstrates excellent electrochemical performance after introducing a conductive interlayer containing a thin piece of carbon nanotube film and MnS promotors.

关键词： promotors polysulfides chemical reactions catalytic ability in-situ Raman measurements

Automated Vulnerability Detection of Blockchain Smart Contacts Based on BERT Artificial Intelligent Model

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7期21卷 237-251页

作者： Feng Yiting Ma Zhaofeng duan Pengfei Luo Shoushan School of Cyberspace Security Beijing University of Posts and TelecommunicationsBeijing 100876China

The widespread adoption of blockchain technology has led to the exploration of its numerous applications in various *** algorithms and smart contracts are critical components of blockchain *** the benefits of virtual currency,vulnerabilities in smart contracts have resulted in substantial losses to *** researchers have identified these vulnerabilities and developed tools for detecting them,the accuracy of these tools is still far from satisfactory,with high false positive and false negative *** this paper,we propose a new method for detecting vulnerabilities in smart contracts using the BERT pre-training model,which can quickly and effectively process and detect smart *** specifically,we preprocess and make symbol substitution in the contract,which can make the pre-training model better obtain contract *** evaluate our method on four datasets and compare its performance with other deep learning models and vulnerability detection tools,demonstrating its superior accuracy.

关键词： BERT blockchain smart contract vulnerability detection

Optimal confrontation position selecting games model and its application to one-on-one air combat

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 417-428页

作者： Zekun duan Genjiu Xu Xin Liu Jiayuan Ma Liying Wang School of Mathematics and Statistics Northwestern Polytechnical UniversityXi'an 710072China International Joint Research Center on Operations Research Optimization and Artificial IntelligenceXi'an 710129China AVIC Xi’an Aeronautics Computing Technique Research Institute Xi'an 710065China Unmanned System Research Institute Northwestern Polytechnical UniversityXi'an 710072China

In the air combat process,confrontation position is the critical factor to determine the confrontation situation,attack effect and escape probability of ***,selecting the optimal confrontation position becomes the primary goal of maneuver *** taking the position as the UAV’s maneuver strategy,this paper constructs the optimal confrontation position selecting games(OCPSGs)*** the OCPSGs model,the payoff function of each UAV is defined by the difference between the comprehensive advantages of both sides,and the strategy space of each UAV at every step is defined by its accessible space determined by the *** we design the limit approximation of mixed strategy Nash equilibrium(LAMSNQ)algorithm,which provides a method to determine the optimal probability distribution of positions in the strategy *** the simulation phase,we assume the motions on three directions are independent and the strategy space is a cuboid to simplify the *** simulations are performed to verify the feasibility,effectiveness and stability of the algorithm.

关键词： Unmanned aerial vehicles(UAVs) Air combat Continuous strategy space Mixed strategy Nash equilibrium

PEGA:probabilistic environmental gradient-driven genetic algorithm considering epigenetic traits to balance global and local optimizations

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2024年第6期25卷 839-855页

作者： Zhiyu duan Shunkun YANG Qi SHAO Minghao YANG School of Reliability and Systems Engineering Beihang UniversityBeijing 100191China

Epigenetics’flexibility in terms of finer manipulation of genes renders unprecedented levels of refined and diverse evolutionary mechanisms *** the epigenetic perspective,the main limitations to improving the stability and accuracy of genetic algorithms are as follows:(1)the unchangeable nature of the external environment,which leads to excessive disorders in the changed phenotype after mutation and crossover;(2)the premature convergence due to the limited types of epigenetic *** this paper,a probabilistic environmental gradientdriven genetic algorithm(PEGA)considering epigenetic traits is *** enhance the local convergence efficiency and acquire stable local search,a probabilistic environmental gradient(PEG)descent strategy together with a multi-dimensional heterogeneous exponential environmental vector tendentiously generates more offsprings along the gradient in the solution ***,to balance exploration and exploitation at different evolutionary stages,a variable nucleosome reorganization(VNR)operator is realized by dynamically adjusting the number of genes involved in mutation and *** on the above-mentioned operators,three epigenetic operators are further introduced to weaken the possible premature problem by enriching genetic *** experimental results on the open Congress on Evolutionary Computation-2017(CEC’17)benchmark over 10-,30-,50-,and 100-dimensional tests indicate that the proposed method outperforms 10 state-of-the-art evolutionary and swarm algorithms in terms of accuracy and stability on comprehensive *** ablation analysis demonstrates that for accuracy and stability,the fusion strategy of PEG and VNR are effective on 96.55%of the test functions and can improve the indicators by up to four orders of ***,the performance of PEGA on the real-world spacecraft trajectory optimization problem is the best in terms of quality of the solution.

关键词： Evolutionary algorithm Epigenetics Epigenetic algorithm Probabilistic environmental vector Variable nucleosome reorganization

Multiplayer Reach-Avoid Differential Games in 3D Space Inspired by Harris'Hawks'Cooperative Hunting Tactics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research 2024年第2期2023卷 41-54页

作者： Wanying Ruan Haibin duan Yongbin Sun Wanmai Yuan Jie Xia State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijingChina Peng Cheng Laboratory ShenzhenChina Information Science Academy of CETC BeijingChina

This paper investigates a multiplayer reach-avoid differential game in 3-dimensional(3D)space,which involves multiple pursuers,multiple evaders,and a designated target *** evaders aim to reach the target region,while the pursuers attempt to guard the target region by capturing the *** class of research holds significant practical ***,the complexity of the problem escalates substantially with the growing number of players,rendering its solution extremely *** this paper,the multiplayer game is divided into many subgames considering the cooperation among pursuers,reducing the computational burden,and obtaining numerically tractable strategies for ***,the Apollonius sphere,a fundamental geometric tool for analyzing the 3D differential game,is formulated,and its properties are *** on this,the optimal interception point for the pursuer to capture the evader is derived and the winning conditions for the pursuer and evader are ***,based on the Apollonius sphere,the optimal state feedback strategies of players are designed,and simultaneously,the optimal one-to-one pairings are ***,the Value function of the multiplayer reach-avoid differential game is explicitly given and is proved to satisfy Hamilton-Jacobi-Isaacs(HJI)***,the matching algorithm for the case with pursuers outnumbered evaders is provided through constructing a weighted bipartite graph,and the cooperative tactics for multiple pursuers are proposed,inspired by the Harris'Hawks intelligent cooperative hunting ***,numerical simulations are conducted to illustrate the effectiveness of the theoretical results for both cases where the number of adversary players is equal and unequal between the 2 groups.

关键词： holds satisfy rendering

Improving the high cycle fatigue property of Ti6Al4V ELI alloy by optimizing the surface integrity through electric pulse combined with ultrasonic surface rolling process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第3期170卷 103-121页

作者： Pengfei Sun Shengguan Qu Chenfeng duan Xiongfeng Hu Xiaoqiang Li National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

To improve the surface integrity and high cycle fatigue property of Ti6Al4V ELI alloy,the electric pulse has been introduced into the ultrasonic surface rolling process(USRP),which is called electric pulse-assisted ultrasonic surface rolling process(EUSRP).With the help of“electroplasticity”of the electric pulse,the thickness of the surface gradient deformation layer was about three times of the USRP specimens by adjusting the pulse current ***,the surface hardness decreases due to the continuous effect of the pulse current and the“skin effect”during *** is worth noting that the higher the applied pulse current,the more severe the *** paradox causes the fatigue performance of EUSRP specimens lower than that of USRP *** break this paradox,the EUSRP treatment is followed by a USRP *** EUSRP-2(with a pulse current of 200 A)+USRP specimens exhibit excellent surface hardness,a gradient deformation layer thickness of about 400μm,low surface roughness and high compressive residual compressive ***,the hardening mechanisms of the different surface strengthening specimens have been quantitatively analyzed in combination with microstructure *** fatigue life of Ti6Al4V ELI alloy can be improved by about 25 times at 780 MPa using the EUSRP-2+USRP treatment,the main reason for the highest fatigue life is the deepest surface gradient layer and the deepest crack initiation *** fatigue limit of the EUSRP-2+USRP specimens is not the highest because too much surface hardening causes compressive residual stress relaxation during cycling and the beneficial effect of compressive residual stress is eliminated.

关键词： Ti6Al4V ELI alloy Combined surface treatment Transmission electron microscopy Residual stress Fatigue performance

A Novel On-Site-Real-Time Method for Identifying Characteristic Parameters Using Ultrasonic Echo Groups and Neural Network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第1期37卷 215-228页

作者： Shuyong duan Jialin Zhang Heng Ouyang Xu Han Guirong Liu State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin 300401China Department of Aerospace Engineering and Engineering Mechanics University of CincinnatiCincinnati 45221USA

On-site and real-time non-destructive measurement of elastic constants for materials of a component in a in-service structure is a challenge due to structural complexities,such as ambiguous boundary,variable thickness,nonuniform material *** work develops for the first time a method that uses ultrasound echo groups and artificial neural network(ANN)for reliable on-site real-time identification of material *** use of echo groups allows the use of lower frequencies,and hence more accommodative to structural *** train the ANNs,a numerical model is established that is capable of computing the waveform of ultrasonic echo groups for any given set of material properties of a given *** waveform of an ultrasonic echo groups at an interest location on the surface the structure with material parameters varying in a predefined range are then computed using the numerical *** results in a set of dataset for training the ANN *** the ANN is trained,the material parameters can be identified simultaneously using the actual measured echo waveform as input to the *** tests have been conducted both numerically and experimentally to evaluate the effectiveness and accuracy of the currently proposed *** results show that the maximum identification error of numerical example is less than 2%,and the maximum identification error of experimental test is less than 7%.Compared with currently prevailing methods and equipment,the proposefy the density and thickness,in addition to the elastic ***,the reliability and accuracy of inverse prediction is significantly ***,it has broad applications and enables real-time field measurements,which has not been fulfilled by any other available methods or equipment.

关键词： Parameter identification Ultrasonic echo group High-precision modeling Artificial neural network NDT

Indefinite metacavities coupled to a mirror:bound states in the continuum with anomalous resonance scaling

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2024年第3期12卷 598-607页

作者： QIANG ZHANG PEIXIANG LI ZHIYUAN GU SHAODING LIU ZEJUN duan College of Electronic Information and Optical Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

Indefinite metacavities(IMCs)made of hyperbolic metamaterials show great advantages in terms of extremely small mode volume due to large wave vectors endowed by the unique hyperbolic ***,quality(Q)factors of IMCs are limited by Ohmic loss of metals and radiative loss of leaked *** the fact that Ohmic loss of metals is inevitable in IMCs,the radiative loss can be further suppressed by leakage *** we propose a mirror coupled IMC structure which is able to operate at Fabry–Pérot bound states in the continuum(BICs)while the hyperbolic nature of IMCs is *** the BIC point,the radiative loss of magnetic dipolar cavity modes in IMCs is completely absent,resulting in a considerably increased Q factor(>90).Deviating from the BIC point,perfect absorption bands(>0.99)along with a strong near-field intensity enhancement(>1.8×10^(4))appear when the condition of critical coupling is almost *** proposed BICs are robust to the geometry and material composition of IMCs and anomalous scaling law of resonance is verified during the tuning of optical *** also demonstrate that the Purcell effect of the structure can be significantly improved under BIC and quasi-BIC regimes due to the further enhanced Q factor to mode volume *** results provide a new train of thought to design ultra-small optical nanocavities that may find many applications benefitting from strong light–matter interactions.

关键词： hyperbolic mirror definite

Machine learning assisted adsorption performance evaluation of biochar on heavy metal

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第5期18卷 29-42页

作者： Qiannan duan Pengwei Yan Yichen Feng Qianru Wan Xiaoli Zhu Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity College of Urban and Environmental SciencesNorthwest UniversityXi’an710127China Department of Environment Science Shaanxi Normal UniversityXi’an710062China

Heavy metals(HMs)represent pervasive and highly toxic environmental pollutants,known for their long latency periods and high toxicity levels,which pose significant challenges for their removal and ***,the removal of heavy metals from the environment is crucial to ensure the water *** materials,known for their intricate pore structures and abundant oxygen-containing functional groups,are frequently harnessed for their effectiveness in mitigating heavy metal ***,conventional tests for optimizing biochar synthesis and assessing their heavy metal adsorption capabilities can be both costly and *** address this challenge,this paper proposes a data-driven machine learning(ML)approach to identify the optimal biochar preparation and adsorption reaction conditions,with the ultimate goal of maximizing their adsorption *** utilizing a data set comprising 476 instances of heavy metal absorption by biochar,seven classical integrated models and one stacking model were trained to rapidly predict the efficiency of heavy metal adsorption by *** predictions were based on diverse physicochemical properties of biochar and the specific adsorption reaction *** results demonstrate that the stacking model,which integrates multiple algorithms,allows for training with fewer samples to achieve higher prediction accuracy and improved generalization ability.

关键词： Machine learning Biochar Heavy metal Adsorption efficiency