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IET International Radar Conference 2023, IRC 2023

作者： Liu, Xiaobin Wu, Qihua Gu, Zhaoyu Liu, Zhenyu Zhao, Feng Xiao, Shunping The State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology National University of Defense Technology ChangSha China

ISBN: (纸本)9781839539954

Coding modulation is utilized to design radar waveform to obtain complex properties so that the waveform is difficult to be recognized. However, traditional coding modulation brings high sidelobe in target range profile which makes the detection performance decrease. To solve this problem, the interrupted coding modulation is proposed in this paper based on the interrupted transmitting and receiving. The signal model is provided and the low sidelobe property of range profile is discussed. Constant false-alarm rate (CFAR) is utilized to evaluate the detection performance of interrupted coding modulation waveform. Simulations are conducted to verify the low sidelobe property and detection performance of the proposed waveform. © The Institution of Engineering & technology 2023.

关键词： Signal modulation

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CHARACTERISTICS ANALYSIS OF STEPPED FREQUENCY CHIRP SIGNAL USING UNIFORM INTERRUPTED MODULATION

CHARACTERISTICS ANALYSIS OF STEPPED FREQUENCY CHIRP SIGNAL U...

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IET International Radar Conference 2023, IRC 2023

作者： Zhao, Tiehua Wu, Qihua Xu, Zhiming Zhao, Feng Xiao, Shunping The State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology National University of Defense Technology Changsha China

ISBN: (纸本)9781839539954

The co-modulation is beneficial for increasing the anti-reconnaissance potential of radar waveform. Stepped frequency chirp (SFC) signal has the characteristics of both linear frequency modulation (LFM) signal and stepped-frequency waveform (SFW). Uniform interrupted modulation (UIM) can increase the complexity of the signal in the time domain. Therefore, the characteristics of the SFC signal with UIM are deduced in this paper. First of all, the processing method of the SFC signal is introduced. Then the characteristics of the SFC signal with UIM are analysed emphatically. The high-resolution range profile (HRRP) of the inter-pulse and intra-pulse interrupted modulation are both deduced respectively. It is concluded that the UIM between pulses brings the HRRP of the SFC signal multiple pseudo peaks extending along the range profile. However, there is no pseudo peak in the HRRP of the intra-pulse interruptedly modulated SFC signal. Signal simulation experiments are carried out with MATLAB to verify the accuracy of the theoretical analysis. © The Institution of Engineering & technology 2023.

关键词： Chirp modulation

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Ladder Time Stepwise Inertia Coordinated Control Method of Multiple Wind Farms to Suppress system Frequency Secondary Drop

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Energy Engineering 2024年第8期121卷 2293-2311页

作者： He Li Xianchao Liu Jidong Li Yuchen Qiu Tongliao PowerSupply Company State Grid East Inner Mongolia Electric Power CompanyTongliao028000China Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology Northeast Electric Power UniversityJilin132012China

Currently,both regulated and deregulated power trading exist in China’s power system,which has caused imbalanced funds in the electricity *** this paper,a simulation analysis of the electricity market with wind energy resources is conducted,and the calculation methods of unbalanced funds are investigated *** detail,the calculation formulas of unbalanced funds are illustrated based on their definition,and a two-track electricity market clearing model is ***,the concept of the dual-track system is explained,and the specific calculation formulas of various types of unbalanced funds are ***,considering the renewable energy consumption,the market clearing model based on DC power flow is constructed and solved;by combining fitting methods of mid-and long-term curves,the unbalanced funds are calculated based on clearing results and formulas.

关键词： Wind power stepwise inertial frequency control secondary drop

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Depositing the PtNi nanoparticles on niobium oxide to enhance the activity and CO-tolerance for alkaline methanol electrooxidation

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Chinese Journal of Structural Chemistry 2023年第11期42卷 25-31页

作者： Xinyi Hu Riguang Zhang Zhao Jiang Department of Chemical Engineering Shaanxi Key Laboratory of Energy Chemical Process IntensificationEngineering Research Center of New Energy System Engineering and Equipment Xi'an Jiaotong UniversityXi'an710049China State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan030000China

Direct methanol fuel cells have the advantages of simple system,convenient operation,high conversion rate and low carbon emission,which are considered as the environmental and friendly energy conversion ***-ever,the low activity,CO-tolerance and high cost of anode catalysts restrict the large-scale commercial ***,it is of great practical significance to design and construct the anodic catalysts with high activity,stability and low cost for methanol oxidation *** this work,the PtM/Nb_(2)O_(5)-C(M=Co,Sn,Ni)catalysts are synthesized by the ethylene glycol solvothermal method using transition metal oxide Nb_(2)O_(5)as the *** catalytic performance of different catalysts is further evaluated for alkaline *** results show that the introduction of Ni(existing in Ni^(2+)and Ni^(3+))has the most obvious improvement for alkaline MOR *** adjusting the doped ratio of Pt:Ni,it is shown that PtNi/Nb_(2)O_(5)-C has the highest mass activity(3877.9 mA-mg_(pt)^(-1)),12 times that of the commercial Pt/C ***,LSV,Tafel and EIS analyses show that PtNi/Nb_(2)O_(5)-C has the lowest onset potential and charge transfer resistance,and the fastest electrocatalytic oxidation rate of *** tests show that the electrochemical stability is also significantly improved with the introduction of Nb_(2)O_(5)and *** with the structural characterization and electrochemical tests,it is found that the evident electronic effect among Pt and Ni,Nb_(2)O_(5)and the hydroxyl brought from Ni species are mainly ascribed for enhancing the activity,CO resistance and stability of PtNi/Nb_(2)O_(5)-C.

关键词： Direct methanol fuel cell Niobium oxide Platinum-based catalysts Methanol oxidation reaction

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Anechoic Chamber Equivalent Simulation Method for Intermittent Transceiver Echo Based on Space Target Electromagnetic Scattering Data

Anechoic Chamber Equivalent Simulation Method for Intermitte...

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IET International Radar Conference 2023, IRC 2023

作者： Qiao, Zhenyu Liu, Xiaobin Xie, Ailun Wu, Qihua Zhao, Feng Wang, Ling The State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology National University of Defense Technology Changsha China

ISBN: (纸本)9781839539954

Electromagnetic simulations and anechoic chamber measurements are commonly used to obtain target characteristics. The use of intermittent transceiver in anechoic chamber can effectively solve the problem of the signal coupling at the receiver. However, the method of equivalent simulation between electromagnetic simulation and intermittent transceiver is rarely discussed. In this paper, an intermittent transceiver echo equivalent simulation method in anechoic chamber is proposed based on space electromagnetic scattering data. Then, the characteristics of scattering points of targets under micro-motion conditions are analyzed. Finally, the equivalent relationship and processing flow between electromagnetic scattering data and intermittent transceiver echo are discussed. Simulations are conducted to verify the effectiveness of the proposed method. © The Institution of Engineering & technology 2023.

关键词： Anechoic chambers

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Stabilization of Perturbed Continuous-Time systems Using Event-Triggered Model Predictive Control

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IEEE Transactions on Cybernetics 2022年第5期52卷 4039-4051页

作者： Wang, Mengzhi Sun, Jian Chen, Jie Zhejiang University State Key Laboratory of Industrial Control Technology Hangzhou310027 China Beijing Institute of Technology Key Laboratory of Intelligent Control and Decision of Complex System Beijing100081 China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China

In this article, event-triggered model predictive control (EMPC) of continuous-time nonlinear systems with bounded disturbances is studied. Two novel event-triggered control schemes are proposed. In the first strategy, an event-triggering condition, designed based on the state error between the actual system state and the optimal one, with an absolute threshold is considered. In the second strategy, an event-triggering condition with a mixed threshold is designed to further save the computational resources. The minimal interevent times of both event-triggered control schemes are obtained to avoid the Zeno behavior. Sufficient conditions of recursive feasibility for these two triggering strategies, which refer to the prediction horizon, the triggering level, and the disturbance bound, are obtained, respectively. Input-to-state practical stability (ISpS) of both event-triggered control systems is established without requiring the system state entering the terminal set in finite time, respectively. Finally, the numerical simulation shows the effectiveness of the proposed methods. © 2013 IEEE.

关键词： Model predictive control

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Rapid Re-Convergence of Real-Time Dynamic Precise Point Positioning by Adding Velocity Constraints

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Gyroscopy and Navigation 2022年第4期13卷 283-293页

作者： Xingxing Wang Sheng, Chuanzhen Yu, Baoguo Zhang, Ziteng Zhang, Jingkui Yi, Qingwu State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang China The 54th Research Institute of China Electronics Technology Group Corporation Shijiazhuang China

Abstract—: In challenging environments like urban vehicle navigation and geological hazards, the GNSS signals are easily blocked, and the long re-convergence time seriously limits many applications of real-time dynamic precise point positioning. Considering that the velocity accuracy is better than the position during re-convergence epochs, we proposed a real-time rapid-positioning method by introducing velocity constraints into the dynamic PPP. According to the different motion states and environments, different velocity constraints are used adaptively. For example, the zero-velocity constraint model is used in the stationary state;the Doppler-velocity constraint model is used when the most visible satellites are temporarily blocked;the other-sensors-velocity constraint model is used when the satellite signal is blocked frequently. Considering that the inaccurate dynamic model will affect the dynamic positioning results, the velocity constraint can be gradually relaxed after the GNSS signals are reacquired and the ambiguity gradually converges. Based on static and kinematic experiments with GPS data, the results show that when the number of visible satellites is greatly dropped due to signal blocking, the new positioning method can significantly speed up the re-convergence of precise point positioning, maintain high accuracy and improve the continuity of real-time dynamic positioning in a short time. © 2022, Pleiades Publishing, Ltd.

关键词： Satellites

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The hydrodynamics of self-rolling locomotion driven by the flexible pectoral fins of 3-D bionic dolphin

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Journal of Ocean Engineering and Science 2022年第1期7卷 29-40页

作者： Zhihan Li Dan Xia Xufeng Zhou Jiabo Cao Weishan Chen Xingsong Wang School of Mechanical Engineering Southeast UniversityNanjing 211189China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150080China

The novel autonomous rolling performance is realized by the pair of pectoral fins of a three-dimensional(3-D)bionic dolphin in this paper numerically.3-D Navier-Stokes equations are employed to simulate the viscous fluid around the bionic *** effect of self-rolling manoeuvrability is ex-plored using the dynamic mesh technology and user-defined function(UDF).By varying the parameter ratios,the interaction of flexible pectoral fins is divided into two motion modes,amplitude differential and frequency differential *** the primary driving source,the differential motion of a pair of pec-toral fins can effectively provide the rolling torque,and the trajectory of the entire rolling process is approximately the clockwise *** results demonstrate that the rolling angular velocity and driving torque in the steady state can be improved by increasing parameter ratios,and the rolling efficiency can reach the maximum under the optimal parameter ***,different parameter ratios do not af-fect the rolling radius of the self-rolling *** evolution process around the pair of pectoral fins is shown by the flow structures in self-rolling swimming,reasonably revealing that self-rolling locomotion is produced by the pressure and wake vortices surrounding the pair of pectoral fins,and the wake struc-tures depend primarily on the variation of parameter *** properly turns out that the application of the pair of pectoral fins can realize the self-rolling performance through parameter differential modes.

关键词： Self-rolling dolphin Parameter differential mode Numerical simulation Hydrodynamic performance Flow structures

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Knowledge-based neural network SPICE modeling for MOSFETs and its application on 2D material field-effect transistors

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Science China(Information Sciences) 2023年第2期66卷 227-236页

作者： Guodong QI Xinyu CHEN Guangxi HU Peng ZHOU Wenzhong BAO Ye LU State Key Laboratory of ASIC and System School of Information Science and TechnologyFudan University State Key Laboratory of ASIC and System School of Microelectronics Fudan University Zhangjiang Fudan International Innovation Center Fudan University

As the traditional scaling of silicon metal-oxide-semiconductor field-effect transistors（MOSFETs） reaches its physical limit, research efforts on novel semiconductor devices are increasingly desired. To enable the joint optimization of early-stage circuit design and process of novel devices, the rapid creation of an accurate compact model of these devices with the capability to cover process variations is required. In this work, a knowledge-based neural network（KNN） modeling method is proposed. This method separates the geometrical variables from the other input variables of the device, where the geometrical variables are modeled with physics-based analytical equations, while the remaining part is modeled by an artificial neural network. The KNN model takes advantage of the automated numerical fitting capability of the neural network and the geometrical scalability from device physics. The created KNN model is first validated with silicon MOSFET data from the industry standard BSIM6 and shows more than 20% accuracy improvement as compared with the traditional neural network model. Furthermore, MoS2field-effect transistors and circuits,such as ring oscillators, standard cells, and logic functional circuits, are experimentally fabricated for model verification. The results show that the KNN model is capable of predicting the electrical characteristics of devices beyond the measurement geometry and facilitates the accurate simulations of statistical circuits with respect to experimental data. This work paves the way for future circuit designs and simulations of novel semiconductor devices.

关键词： knowledge-based neural network MOSFET 2D material FETs Monte Carlo simulations circuit benchmark

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Engineering design of feedstock powder and relevant thermal-mechanical performance of thermal/environmental barrier coatings

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Journal of Advanced Ceramics 2025年第2期14卷 37-56页

作者： Xinchang Feng Fangwei Guo Lirong Luo Yuzhang Wang Yun Long Xiaofeng Zhao Fei Pan Lei Guo Qingfeng Zeng Jing Feng Chunlei Wan Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China National Engineering Research Center of Special Equipment and Power System for Ship and Marine Engineering Shanghai 200030China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Advanced Nuclear Energy Technology Nuclear Power Institute of ChinaChengdu 610213China Innovative Sensor Technology IST AG Ebnat-Kappel 9642Switzerland School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianmushan Laboratory Hangzhou 311115China School of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The development of aeroengine with a high thrust-weight ratio poses great challenges for current top-coating thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) in service. Medium/high-entropy ceramics are highly promising candidate material for advanced TBCs/EBCs owing to their low thermal conductivity, high melting point, high-temperature stability, and calcium–magnesium–alumino–silicate (CMAS) resistance. Most feedstock powder used for medium/high-entropy TBCs/EBCs is prepared via traditional spray drying, which cannot fully exploit the advantages of multicomponent ceramics. The density, sphericity, inner structure, and flowability of feedstock powder affect their melting state during the thermal spraying process, which strongly affects the microstructure and properties of the deposited coatings. Therefore, the deposited coatings exhibit phase segregation, amorphous phases, and microstructure defects owing to unpredictable variations in feedstock powder with random morphologies and structures. Here, the structure and properties of feedstock powder prepared by state-of-the-art granulation technologies and their influences on the deposited coatings were systematically investigated, which can provide guidance for configuration optimization of feedstock powder and the manufacturing accuracy of the deposited coating. This review aims to bridge the gap between cutting-edge ceramics and advanced engineering technologies, thus providing concrete background knowledge and crucial guidelines for designing and developing TBCs/EBCs.

关键词： thermal/environmental barrier coatings(TBCs/EBCs) spraying ceramic powder multiscale structure control high-entropy ceramics thermal-mechanical performance

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