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Serial Failure Diagnosis of a Transmission Line Protection Relaying System by Petri Nets

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Journal of Systems engineering and electronics 2001年第1期12卷 59-64页

作者： Zhang Zhiming Wang Yue Tao Ran &Zhou Siyong dept. of electronics engineering, beijing institute of technology, 100081, P. R. China dept. of electronics engineering Beijing Institute of Technology 100081 P. R. China

With the development of large-scale complicated modern power systems, the requirement for the associated protection scheme tends to be more stringent and its combination more complex. However, it is very difficult to figure out the factors of failure of such systems. This paper proposes a Petri net model of a transmission line protection relaying system, including three types of relays as well as an automatic reclosing device, and shows how to diagnose serial failure of the system by analyzing invariant sets of the model. Furthermore, it gives four basic types of failure sequences and its execution is much more intuitive and effective than the traditional method.

关键词： Electric fault location Electric power system protection Electric relays Failure analysis Mathematical models Petri nets Relay protection

Pupillometry Analysis of Rapid Serial Visual Presentation at Five Presentation Rates

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Tsinghua Science and technology 2024年第2期29卷 543-552页

作者： Xi Luo Yanfei Lin Rongxiao Guo Xirui Zhao Shangen Zhang Xiaorong Gao School of Integrated Circuits and electronics Beijing Institute of TechnologyBeijing 100081China School of Computer and Communication engineering University of Science and Technology BeijingBeijing 100083China School of Medicine Tsinghua UniversityBeijing 100084China

In this study,the effect of presentation rates on pupil dilation is investigated for target recognition in the Rapid Serial Visual Presentation(RSVP)paradigm.In this experiment,the RSVP paradigm with five different presentation rates,including 50,80,100,150,and 200 ms,is designed.The pupillometry data of 15 subjects are collected and analyzed.The pupillometry results reveal that the peak and average amplitudes for pupil size and velocity at the 80-ms presentation rate are considerably higher than those at other presentation rates.The average amplitude of pupil acceleration at the 80-ms presentation rate is significantly higher than those at the other presentation rates.The latencies under 50-and 80-ms presentation rates are considerably lower than those of 100-,150-,and 200-ms presentation rates.Additionally,no considerable differences are observed in the peak,average amplitude,and latency of pupil size,pupil velocity,and acceleration under 100-,150-,and 200-ms presentation rates.These results reveal that with the increase in the presentation rate,pupil dilation first increases,then decreases,and later reaches saturation.The 80-ms presentation rate results in the largest point of pupil dilation.No correlation is observed between pupil dilation and recognition accuracy under the five presentation rates.

关键词： pupil dilation presentation rate Rapid Serial Visual Presentation(RSVP)

Experimental study of solid-liquid origami composite structures with improved impact resistance

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 118-123页

作者： Shuheng Wang Zhanyu Wang Bei Wang Zhi Liu Yunzhu Ni Wuxing Lai Shan Jiang Yong An Huang AML Department of Engineering MechanicsLaboratory of Flexible Electronics TechnologyTsinghua UniversityBeijing 100084China institute of Advanced Structure technology Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and StructuresBeijing Institute of TechnologyBeijing 100081China Hangzhou institute of technology Xidian UniversityHangzhou 311200China Nanjing Research Institude of electronics technology Nanjing 210039China The institute of engineering Thermophysics Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Intelligent Manufacturing Equipment and technology Huazhong University of Science and TechnologyWuhan 430074China

In this paper,a liquid-solid origami composite design is proposed for the improvement of impact resistance.Employing this design strategy,Kresling origami composite structures with different fillings were designed and fabricated,namely air,water,and shear thickening fluid(STF).Quasi-static compression and drop-weight impact experiments were carried out to compare and reveal the static and dynamic mechanical behavior of these structures.The results from drop-weight impact experiments demonstrated that the solid-liquid Kresling origami composite structures exhibited superior yield strength and reduced peak force when compared to their empty counterparts.Notably,the Kresling origami structures filled with STF exhibited significantly heightened yield strength and reduced peak force.For example,at an impact velocity of 3 m/s,the yield strength of single-layer STF-filled Kresling origami structures increased by 772.7%and the peak force decreased by 68.6%.This liquid-solid origami composite design holds the potential to advance the application of origami structures in critical areas such as aerospace,intelligent protection and other important fields.The demonstrated improvements in impact resistance underscore the practical viability of this approach in enhancing structural performance for a range of applications.

关键词： Solid-liquid design Origami structure Impact resistance Shear thickening fluid

A Residual Frequency Offset Estimation Method Based on Range Migration Fitting

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Journal of beijing institute of technology 2024年第2期33卷 103-110页

作者： Liting Zhang Hao Huan Ran Tao Xiaogang Tang School of Information and electronics Beijing Institute of Technology School of Aerospace Information Space Engineering University

Recently, researchers have proposed an emitter localization method based on passive synthetic aperture. However, the unknown residual frequency offset(RFO) between the transmitter and the receiver causes the received Doppler signal to shift, which affects the localization accuracy. To solve this issue, this paper proposes a RFO estimation method based on range migration fitting. Due to the high frequency modulation slope of the linear frequency modulation(LFM)-modulation radar signal, it is not affected by RFO in range compression. Therefore, the azimuth time can be estimated by fitting the peak value position of the pulse compression in range direction.Then, the matched filters are designed under different RFOs. When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time, the given RFO is the real RFO between the transceivers. The simulation results show that the estimation error of azimuth distance does not exceed 20 m when the received signal duration is not less than 3 s, the pulse repetition frequency(PRF) of the transmitter radar signal is not less than 1 k Hz, the range detection is not larger than 1 000 km, and the signal noise ratio(SNR) is not less than –5 d B.

关键词： passive localization range migration fitting (RMF) residual frequency offset (RFO)

Self-healable gels in electrochemical energy storage devices

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Nano Research 2024年第4期17卷 3302-3323页

作者： Yang Li PeiPei Ding Yuzhe Gu Sheng Qian Yuncong Pang Lele Wang Jiayang Feng Baoguang Liu Qi Wan Ping Li Zhiwei Liu College of Electronic and Optical engineering&College of Flexible electronics(Future technology) Nanjing University of Posts&Telecommunications(NJUPT)Nanjing 210023China State Key Laboratory of Organic electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts and Telecommunications(NJUPT)Nanjing 210023China College of Materials Science&engineering Beijing University of TechnologyBeijing 100124China beijing Advanced Innovation Center for Materials Genome engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Pillar of engineering Product Development Singapore University of Technology and DesignSingapore 487372Singapore School of Energy and Environmental engineering University of Science and Technology BeijingBeijing 100083China

In the green energy and carbon-neutral technology,electrochemical energy storage devices have received continuously increasing attention recently.However,due to the unavoidable volume expansion/shrinkage of key materials or irreversible mechanical damages during application,the stability of energy storage and delivery as well as the lifetime of these devices are severely shortened,leading to serious performance degradation or even safety issues.Therefore,the utilization of self-healable gels into electrochemical energy storage devices,such as electrodes,binders,and electrolytes,is proven as an effective method to realize long-term stable operation of these devices via the self-repairing of mechanical and electrochemical characteristics.Herein,this review first summarizes the feature and fabrication of different gels,paying special attention to hydrogels,organohydrogels,and ionogels.Then,basic concepts and figure of merit of self-healable gels are analyzed with a detailed discussion at the healing mechanisms,from reversible dynamic bonds to physical molecular diffusion,and to external healing trigger.Then we introduce all the important parts of electrochemical energy storage devices,which could be replaced by healable gels to enhance the durability,including electrodes,binders,and electrolytes.Finally,the critical challenges and future perspectives regarding the future development of healable gels based high-performance electrochemical energy storage devices or electronics are provided.

关键词： self-healable gels healing mechanisms electrodes binders gel electrolytes

Design of integral sliding mode guidance law based on disturbance observer

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Journal of Systems engineering and electronics 2024年第1期35卷 186-194页

作者： ZHOU Jianping ZHANG Wenjie ZHOU Hang LI Qiang XIA Qunli School of Aerospace engineering Beijing Institute of TechnologyBeijing 100081China School of Informatic engineering Mianyang Techers’CollegeMianyang 62100China beijing institute of Electronic System engineering Beijing 100854China beijing institute of Space Long March Vehicle Beijing 100076China

With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(ISMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular line-of-sight.At the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance command.The proposed system’s stability is proven based on the Lyapunov stability criterion.The simulations reveale that ISMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance laws.Furthermore,ISMGL has a more accurate impact angle and fast convergence speed.

关键词： disturbance observer pilot dynamics integral sliding mode impact angle constraint maneuvering target

Time-varying parameters estimation with adaptive neural network EKF for missile-dual control system

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Journal of Systems engineering and electronics 2024年第2期35卷 451-462页

作者： YUAN Yuqi ZHOU Di LI Junlong LOU Chaofei School of Astronautics Harbin Institute of TechnologyHarbin 150001China beijing institute of Electronic System engineering Beijing 100854China

In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.

关键词： long-short-term memory(LSTM)neural network extended Kalman filter(EKF) rolling training time-varying parameters estimation missile dual control system

Molecular dynamics study of primary radiation damage in TiVTa concentrated solid-solution alloy

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Chinese Physics B 2024年第3期33卷 530-535页

作者：赵永鹏豆艳坤贺新福曹晗王林枫邓辉球杨文 Reactor engineering technology Research Division China Institute of Atomic EnergyBeijing 102413China School of Physics and electronics Hunan UniversityChangsha 410082China

The primary radiation damage in pure V and TiVTa concentrated solid-solution alloy(CSA)was studied using a molecular dynamics method.We have performed displacement cascade simulations to explore the generation and evolution behavior of irradiation defects.The results demonstrate that the defect accumulation and agglomeration in TiVTa CSA are significantly suppressed compared to pure V.The peak value of Frenkel pairs during cascade collisions in TiVTa CSA is much higher than that in pure V due to the lower formation energy of point defects.Meanwhile,the longer lifetime of the thermal spike relaxation and slow energy dissipation capability of TiVTa CSA can facilitate the recombination of point defects.The defect agglomeration rate in TiVTa CSA is much lower due to the lower binding energy of interstitial clusters and reduced interstitial diffusivity.Furthermore,the occurrence probability of dislocation loops in TiVTa CSA is lower than that in pure V.The reduction in primary radiation damage may enhance the radiation resistance of TiVTa CSA,and the improved radiation tolerance is primarily attributed to the relaxation stage and long-term defect evolution rather than the ballistic stage.These results can provide fundamental insights into irradiation-induced defects evolution in refractory CSAs.

关键词： concentrated solid-solution alloy primary radiation damage molecular dynamics simulation

ZnSb/Ti_(3)C_(2)T_(x)MXene van der Waals heterojunction for flexible near-infrared photodetector arrays

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Journal of Semiconductors 2024年第5期45卷 99-105页

作者： Chuqiao Hu Ruiqing Chai Zhongming Wei La Li Guozhen Shen State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronic engineering University of Chinese Academy of SciencesBeijing 100049China School of Integrated Circuits and electronics Beijing Institute of TechnologyBeijing 100081China

Two-dimension(2D)van der Waals heterojunction holds essential promise in achieving high-performance flexible near-infrared(NIR)photodetector.Here,we report the successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene based flexible NIR photodetector array via a facile photolithography technology.The single ZnSb/Ti_(3)C_(2)T_(x)photodetector exhibited a high light-to-dark current ratio of 4.98,fast response/recovery time(2.5/1.3 s)and excellent stability due to the tight connection between 2D ZnSb nanoplates and 2D Ti_(3)C_(2)T_(x)MXene nanoflakes,and the formed 2D van der Waals heterojunction.Thin polyethylene terephthalate(PET)substrate enables the ZnSb/Ti_(3)C_(2)T_(x)photodetector withstand bending such that stable photoelectrical properties with non-obvious change were maintained over 5000 bending cycles.Moreover,the ZnSb/Ti_(3)C_(2)T_(x)photodetectors were integrated into a 26×5 device array,realizing a NIR image sensing application.

关键词： ZnSb nanoplates Ti_(3)C_(2)T_(x)MXene van der Waals heterojunction flexible photodetector image sensing