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Defence Technology（防务技术） 2024年第3期33卷 352-363页

作者： Xinwei Wang Xiaopeng Yan Tai An Qile Chen Dingkun Huang Science and Technology on electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China

Uniform linear array(ULA)radars are widely used in the collision-avoidance radar systems of small unmanned aerial vehicles(UAVs).In practice,a ULA's multi-target direction of arrival(DOA)estimation performance suffers from significant performance degradation owing to the limited number of physical *** improve the underdetermined DOA estimation performance of a ULA radar mounted on a small UAV platform,we propose a nonuniform linear motion sampling underdetermined DOA estimation *** the motion of the UAV platform,the echo signal is sampled at different ***,according to the concept of difference co-array,a virtual ULA with multiple array elements and a large aperture is synthesized to increase the degrees of freedom(DOFs).Through position analysis of the original and motion arrays,we propose a nonuniform linear motion sampling method based on ULA for determining the optimal *** the condition of no increase in the aperture of the physical array,the proposed method obtains a high DOF with fewer sampling runs and greatly improves the underdetermined DOA estimation performance of *** results of numerical simulations conducted herein verify the superior performance of the proposed method.

关键词： Unmanned aerial vehicle(UAV) Uniform linear array(ULA) Direction of arrival(DOA) Difference co-array Nonuniform linear motion sampling method

Cognitive interference decision method for air defense missile fuze based on reinforcement learning

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Defence Technology（防务技术） 2024年第2期32卷 393-404页

作者： Dingkun Huang Xiaopeng Yan Jian Dai Xinwei Wang Yangtian Liu Science and Technology on electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China

To solve the problem of the low interference success rate of air defense missile radio fuzes due to the unified interference form of the traditional fuze interference system,an interference decision method based Q-learning algorithm is ***,dividing the distance between the missile and the target into multiple states to increase the quantity of state ***,a multidimensional motion space is utilized,and the search range of which changes with the distance of the projectile,to select parameters and minimize the amount of ineffective interference *** interference effect is determined by detecting whether the fuze signal ***,a weighted reward function is used to determine the reward value based on the range state,output power,and parameter quantity information of the interference *** effectiveness of the proposed method in selecting the range of motion space parameters and designing the discrimination degree of the reward function has been verified through offline experiments involving full-range missile *** optimal interference form for each distance state has been *** with the single-interference decision method,the proposed decision method can effectively improve the success rate of interference.

关键词： Cognitive radio Interference decision Radio fuze Reinforcement learning Interference strategy optimization

The Influence of CO_(2) Cured Manganese Slag on the Performance and Mechanical Properties of Ultra-High Performance Concrete

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1717-1730页

作者： Ligai Bai Guihua Yang school of architectural engineering North China Institute of Aerospace EngineeringLangfang065000China

The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential *** CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this material,thereby mitigating their release into the natural *** study investigates the impact of CO_(2) cured MS on various rheological parameters,including slump flow,plastic viscosity(η),and yield shear stress(τ).Additionally,it assesses flexural and compressive strengths(f_(t) and f_(cu)),drying shrinkage rates(DSR),durability indicators(chloride ion migration coefficient(CMC),carbonization depth(CD)),and the leaching behavior of heavy metal *** examination via scanning electron microscopy(SEM)is employed to elucidate the underlying *** results indicate that CO_(2) curing significantly enhances the slump flow of ultra-high performance concrete(UHPC)by up to 51.2%.Moreover,it reduces UHPC’sηandτby rates ranging from 0%to 52.7%and 0%to 40.2%,*** DSR exhibits a linear increase corresponding to the mass ratio of CO_(2) cured ***,CO_(2) curing enhances both f_(t) and f_(cu) of UHPC by up to 28.7%and 17.6%,*** electrical resistance is also improved,showing an increase of up to 53.7%.The relationship between mechanical strengths and electrical resistance follows a cubic *** CO_(2) cured MS demonstrates a notable decrease in the CMC and CD by rates ranging from 0%to 52.6%and 0%to 26.1%,*** reductions of leached chromium(Cr)and manganese(Mn)are up to 576.3%and 1312.7%,***,CO_(2) curing also enhances the compactness of UHPC,thereby demonstrating its potential to improve both mechanical and durability properties.

关键词： CO_(2)curing manganese slag steel fibers mechanical strengths salt action

Field Load Test Based SHM System Safety Standard Determination for Rigid Frame Bridge

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Structural Durability & Health Monitoring 2024年第3期18卷 361-376页

作者： Xilong Zheng Qiong Wang Di Guan school of Civil and architectural engineering Harbin UniversityHarbin150076China

The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation process. Thestiffness of the repaired bridge is improved, and the maximum deflection of the load test is reduced from 37.9 to27.6 mm. A bridge health monitoring system is installed after the bridge is reinforced. To achieve an easy assessmentof the bridge’s safety status by directly using transferred data, a real-time safety warning system is createdbased on a five-level safety standard. The threshold for each safety level will be determined by theoretical calculationsand the outcomes of static loading tests. The highest risk threshold will be set at the ultimate limit statevalue. The remaining levels, namely middle risk, low risk, and very low risk, will be determined usingreduction coefficients of 0.95, 0.9, and 0.8, respectively.

关键词： Continuous rigid frame bridge rehabilitation long-term monitoring field load test safety standard determination

Comprehensive Exergoeconomic Analysis and Optimization of a Novel Zero-Carbon-Emission Multi-Generation System based on Carbon Dioxide Cycle

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Journal of Thermal Science 2024年第3期33卷 1065-1081页

作者： SUN Yan LI Hongwei WANG Di DU Changhe school of Energy and Power engineering Northeast Electric Power UniversityJilin132012China school of Automation engineering Northeast Electric Power UniversityJilin132012China Xi’an Institute of electromechanical Information Technology Xi’an710065China

This paper aims to conduct a comprehensive exergoeconomic analysis of a novel zero-carbon-emission multi-generation system and propose a fast optimization method combined with machine *** detailed exergoeconomic analysis of a novel combined power,freshwater and cooling multi-generation system is performed in this *** exergoeconomic analysis model is established by exergy flow theory.A comprehensive exergy,exergoeconomic and environmental analysis is carried *** critical decision variables are researched to bring out effects on the multi-generation system exergoeconomic performance.A novel fast optimization method combining genetic algorithm and Bagging neural network is *** advanced nature comparison is made between the proposed system and four similar *** display that increasing the turbine inlet temperature can improve exergy efficiency and decrease the total product unit *** multi-generation system exergy destruction directly determines exergy efficiency and total exergy destruction cost *** total product unit cost in the cost optimal design case is reduced by 7.7%and 25%,respectively,compared with exergy efficiency optimal design case and basic design *** with four similar cases,the proposed multi-generation system has great advantages in thermodynamic performance and exergoeconomic *** paper can provide research methods and ideas for performance analysis and fast optimization of multi-generation system.

关键词： waste heat recovery exergoeconomic analysis supercritical carbon dioxide optimization machine learning

Dynamic behavior analysis, color image encryption and circuit implementation of a novel complex memristive system

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Optoelectronics Letters 2024年第3期20卷 183-192页

作者： XIONG Li WANG Xuan ZHANG Xinguo HE Tongdi school of Physics and electromechanical engineering Hexi UniversityZhangye 734000China school of Information Science and engineering Dalian Polytechnic UniversityDalian 116034China school of Information Science and engineering Lanzhou UniversityLanzhou 730000China

This paper is devoted to introduce a novel four-dimensional memristor-involved system and its applications in image encryption and chaotic circuit. The typical dynamical behaviors of the memristor-involved system are explored, such as chaotic phase potraits, Lyapunov exponent spectrum(LES), bifurcation diagram(BD) and complexity analysis. Then a color image encryption algorithm is designed. In this algorithm, the sequences generated by the four-dimensional memristor-involved system are used in scrambling and diffusion algorithm for three channels.

关键词： image system chaotic

Cr-assisted low-temperature densification of(Ti,Zr,Nb,Ta,Mo)C high-entropy carbides with ultrafine grain and enhanced hardness

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Journal of Advanced Ceramics 2024年第6期13卷 780-788页

作者： Yang Liu Jiaji Liang Weiming Guo Shikuan Sun Yu Tian Hua-Tay Lin school of electromechanical engineering Guangdong University of TechnologyGuangzhou 510006China State Key Laboratory of High Performance Tools Guangdong University of TechnologyGuangzhou 510006China school of Material Science and Energy engineering Foshan UniversityFoshan 528000China

While the use of low-melting-point metals as sintering aids for high-entropy carbide(HEC)ceramics has been well established,their existence can compromise hardness due to residual metallic *** study demonstrates an innovative strategy to meet this challenge,where(Ti,Zr,Nb,Ta,Mo)C high-entropy carbide ceramics with ultrafine grains and enhanced hardness are obtained through chromium(Cr)-metal-assisted spark plasma sintering(SPS)at a temperature as low as 1600℃.The results show that the addition of 5 vol%Cr promotes the formation of highly densified single HEC phase ceramics with a high relative density(98.4%)and an ultrafine-grained microstructure(0.17μm).This low-temperature densification mechanism can be attributed to Cr’s solid-solution effect within the matrix and the increased carbon vacancies generated during *** grain size of the(Ti,Zr,Nb,Ta,Mo)C ceramics with 5 vol%Cr metal addition is significantly smaller than that of Cr-free(Ti,Zr,Nb,Ta,Mo)C ceramics sintered at 2000℃(3.03μm)or via traditional low-temperature liquid-phase sintering(1.3–1.5μm).Importantly,the addition of 5 vol%Cr substantially increased the hardness of the ceramics,with a remarkable increase from 23.57 to 28.16 GPa compared to that of the pure(Ti,Zr,Nb,Ta,Mo)C ceramics,owing to the fine-grain strengthening and solid-solution strengthening *** work highlights the uniqueness of Cr metal as a sintering aid in achieving densification and hardness improvements in(Ti,Zr,Nb,Ta,Mo)C ceramics,offering a promising strategy for improving the properties of HEC materials for further development in the near future.

关键词： solid solution sinterability hardness enhancement (Ti,Zr,Nb,Ta,Mo)C high-entropy carbide(HEC)ceramics

Automatic modulation recognition of radiation source signals based on two-dimensional data matrix and improved residual neural network

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Defence Technology（防务技术） 2024年第3期33卷 364-373页

作者： Guanghua Yi Xinhong Hao Xiaopeng Yan Jian Dai Yangtian Liu Yanwen Han Science and Technology on electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China BIT Tangshan Research Institute Beijing 100081China

Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive ***,the AMR of radiation source signals at low SNRs still faces a great ***,the AMR method of radiation source signals based on two-dimensional data matrix and improved residual neural network is proposed in this ***,the time series of the radiation source signals are reconstructed into two-dimensional data matrix,which greatly simplifies the signal preprocessing ***,the depthwise convolution and large-size convolutional kernels based residual neural network(DLRNet)is proposed to improve the feature extraction capability of the AMR ***,the model performs feature extraction and classification on the two-dimensional data matrix to obtain the recognition vector that represents the signal modulation *** analysis and simulation results show that the AMR method based on two-dimensional data matrix and improved residual network can significantly improve the accuracy of the AMR *** recognition accuracy of the proposed method maintains a high level greater than 90% even at -14 dB SNR.

关键词： Automatic modulation recognition Radiation source signals Two-dimensional data matrix Residual neural network Depthwise convolution

Microstructure design of advanced magnesium-air battery anodes

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Journal of Magnesium and Alloys 2024年第2期12卷 443-464页

作者： Xu Huang Qingwei Dai Qing Xiang Na Yang Gaopeng Zhang Ao Shen Wanming Li school of Metallurgy and Materials engineering Chongqing University of Science and TechnologyChongqing 401331China school of Materials and architectural engineering Guizhou Normal UniversityGuiyang 550025China school of Material and Metallurgy University of Science and Technology LiaoningAnshan 114051China

Metal-air battery is an environmental friendly energy storage system with unique open ***(Mg)and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy density,low cost,and ***,the study on Mg-air battery(MAB)is still at the laboratory level currently,mainly owing to the low anodic efficiency caused by the poor corrosion *** order to reduce corrosion losses and achieve optimal utilization efficiency of Mg anode,the design strategies are reviewed from microstructure ***,the corrosion behaviors have been discussed,especially the negative difference effect derived by hydrogen *** attention is given to the effect of anode micro-structures on the MAB,which includes grain size,grain orientation,second phases,crystal structure,twins,and *** further improvement,the discharge performance,long period stacking ordered phase and its enhancing effect are ***,given the current debates over Mg dendrites,the potential risk,the impact on discharge,and the elimination strategies are *** control and single crystal would be promising ways for MAB anode.

关键词： Magnesium Air battery Anode Microstructure Anodic efficiency

Influence of pile-raft connection on lateral performance of combined pile-raft foundations adjacent to tunnelling

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Underground Space 2024年第2期15卷 176-187页

作者： Wenbo Gu Liyuan Tong Huangsong Pan Hongjiang Li Institute of Geotechnical engineering Southeast UniversityNanjing 211189China Department of Architecture and architectural engineering Kyoto UniversityKyoto 6158540Japan school of Architecture and Civil engineering Xihua UniversityChengdu 610039China

The lateral response of combined pile-raft foundations(CPRFs)adjacent to tunnel excavation is a challenging problem owing to the complexity of the pile-raft *** current engineering practices,the impact of these connections on the lateral performance of CPRFs is frequently overlooked,despite their *** address this issue,this study conducted three-dimensional finite element analyses to evaluate the contribution of pile-raft connections to the tunnelling-induced lateral performance of CPRFs in saturated *** the analysis,both passive and active loading at the pile head could be considered by varying the tunnel *** parameter studies,such as relative pile-raft modulus,pile embedded modulus,pile embedded depths,and pile shaft skin friction,were conducted to determine the optimal design parameters for *** results indicate that pile-raft connections significantly affect the tunnellinginduced deflections and bending moments of pile *** by the results,a simplified design method,the pile-raft connection coefficient Kc was ***,the pile-head restraint percentage was established to make a relationship with the pile-raft connection coefficient in order to assess the pile-raft connection and guide the pile-raft *** this paper,the recommended range value of Kc is 10–200 and the range value of pile-head restraint percentage is 24%–42%.

关键词： Combined pile-raft foundations Tunnelling Lateral performance Pile-raft connection