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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

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 {1. Northeast Electric Power UniversityJilin132012China school of Automation {1. 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 {1. engineering Hexi UniversityZhangye 734000China school of Information Science and {1. Dalian Polytechnic UniversityDalian 116034China school of Information Science and {1. 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 {1. engineering Guangdong University of TechnologyGuangzhou 510006China State Key Laboratory of High Performance Tools Guangdong University of TechnologyGuangzhou 510006China school of Material Science and Energy {1. 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 1.00℃.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(0.1.μm).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 28.1. 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 -1. dB SNR.

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

Automatic modulation recognition of radio fuzes using a DR2D-based adaptive denoising method and textural feature extraction

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Defence Technology（防务技术） 2024年第4期34卷 328-338页

作者： Yangtian Liu Xiaopeng Yan Qiang Liu Tai An Jian Dai Science and Technology on electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China China Research and Development Academy of Machinery Equipment Beijing 100089China

The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference ***,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio *** solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is ***,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)***,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for *** DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-1. d B and above,which is higher than that of other typical *** trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-1. d B and above,which represents a good AMR performance of radio fuzes under low SNRs.

关键词： Automatic modulation recognition Adaptive denoising Data rearrangement and the 2D FFT(DR2D) Radio fuze

A single micro-LED manipulation system based on micro-gripper

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Nanotechnology and Precision engineering 2024年第2期7卷 45-52页

作者： Jie Bai Pingjuan Niu Erdan Gu Jianming Li Clarence Augustine TH Tee school of Mechanical {1. Tiangong University school of Electronic and Information {1. Tiangong University Institute of Photonics University of Strathclyde Tianjin Key Laboratory of Micro Low Gravity Environment Simulation Technology Tianjin Aerospace Electromechanical Equipment Research Institute Department of Electrical and Information engineering School of Physics and Electrical Information EngineeringZhejiang Normal University

Micro-LEDs(μLEDs) have advantages in terms of brightness, power consumption, and response speed. In addition, they can also be used as micro-sensors implanted in the body via flexible electronic skin. One of the key techniques involved in the fabrication of μLED-based devices is transfer printing. Although numerous methods have been proposed for transfer printing, improving the yield of μLED arrays is still a formidable task. In this paper, we propose a novel method for improving the yield of μLED arrays transferred by the stamping method, using an innovative design of piezoelectrically driven asymmetric micro-gripper. Traditional grippers are too large to manipulate μLEDs, and therefore two micro-sized cantilevers are added at the gripper tips. A μLED manipulation system is constructed based on the micro-gripper together with a three-dimensional positioning system. Experimental results using this system show that it can be used successfully to manipulate μLED arrays.

关键词： Micro-gripper Micro-LED Transfer printing Manipulation

Construction and manipulation of origami-inspired tubular structures with controlled mechanical buckling for collection and transportation of microspheres based on optically induced electrokinetics

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Science China(Technological Sciences) 2024年第9期67卷 2954-2964页

作者： YANG WenGuang WANG WenHao TENG XiangYu QIAO ZeZheng YU HaiBo school of {1. and Automotive engineering Yantai UniversityYantai 264005China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China

The development of microengineered hydrogels has opened up unlimited possibilities for designing complex structures at the microscale. In this study, we constructed an origami-inspired tubular structure with controlled mechanical buckling based on optically induced electrokinetics(OEK). By inducing a stress gradient in the thickness, a tubular structure can be formed from a poly(ethylene glycol) diacrylate(PEGDA) hydrogel film of various shapes that have been custom fabricated. To achieve an ideal three-dimensional(3D) structure, the amplitude of the tubular structure can be controlled by adjusting the aspect ratios or polymerization time. Furthermore, the tubular structure can be manipulated for the collection and transportation of *** summary, we provide an effective method for designing 3D structures at the micro-nano scale. This forming method holds great potential for achieving various functions in tissue engineering, drug packaging, and transportation in the future.

关键词： origami-inspired tubular structures optically induced electrokinetics microfabrication mechanical buckling

Kinematic-mapping-model-guided analysis and optimization of 2-PSS&1.RR circular-rail parallel mechanism for fully steerable phased array antennas

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Defence Technology 2024年第8期38卷 136-154页

作者： Guodong Tan Xiangfei Meng Xuechao Duan Lulu Cheng Dingchao Niu Shuai He Dan Zhang Laboratory of electromechanical Coupling in Electronic Equipment Xidian University Department of Mechanical engineering The Hong Kong Polytechnic University

This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1.RR circular-rail parallel mechanism. Initially, a comparative motion analysis between the 3D model of the mount and its full-scale prototype is conducted to validate effectiveness. Given the inherent complexity, a kinematic mapping model is established between the mount and the crank-slider linkage, providing a guiding framework for subsequent analysis and optimization. Guided by this model, feasible inverse and forward solutions are derived, enabling precise identification of stiffness singularities. The concept of singularity distance is thus introduced to reflect the structural stiffness of the mount. Subsequently, also guided by the mapping model, a heuristic algorithm incorporating two backtracking procedures is developed to reduce the mount's mass. Additionally, a parametric finite-element model is employed to explore the relation between singularity distance and structural stiffness. The results indicate a significant reduction(about 1.%) in the antenna mount's mass through the developed algorithm, while highlighting the singularity distance as an effective stiffness indicator for this type of antenna mount.

关键词： Backtracking Circular rail Crank-slider linkage Innovative antenna mount Kinematic mapping model Stiffness singularity