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Scintillation Arc from FRB 20220912A

science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 134-142页

作者： Zi-Wei Wu Robert AMain Wei-Wei Zhu Bing Zhang Peng Jiang Jia-Rui Niu Jin-Lin Han Di Li Ke-Jia Lee Dong-Zi Li Yuan-Pei Yang Fa-Yin Wang Rui Luo Pei Wang Chen-Hui Niu Heng Xu Bo-Jun Wang Wei-Yang Wang Yong-Kun Zhang Yi Feng De-Jiang Zhou Yong-Hua Xu Can-Min Deng Yu-Hao Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Max-Planck-Institut für Radioastronomie Bonn 53121Germany Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Nevada Center for Astrophysics and Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Department of Astronomy Peking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Cahill Center for Astronomy and Astrophysics California Institute of TechnologyPasadena 91125USA South-Western Institute For Astronomy Research Yunnan UniversityKunming 650504China School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210023China CSIRO Space and Astronomy Epping 1710Australia Department of Astronomy School of Physics and Materials ScienceGuangzhou UniversityGuangzhou 510006China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Yunnan Observatories Chinese Academy of SciencesKunming 650011China Guangxi Key Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

We present the interstellar scintillation analysis of fast radio burst(FRB)20220912A during its extremely active episode in 2022using data from the Five-hundred-meter Aperture Spherical Radio Telescope(FAST).We detect a scintillation arc in the FRB’s secondary spectrum,which describes the power in terms of the scattered FRB signals’time delay and Doppler *** arc indicates that the scintillation is caused by a highly localized *** analysis favors a Milky Way origin of the ionized interstellar medium(IISM)for the localized scattering medium but cannot rule out a host galaxy *** present our method for detecting the scintillation arc,which can be applied generally to sources with irregularly spaced bursts or *** methods could help shed light on the complex interstellar environment surrounding the FRBs and in our Galaxy.

关键词： fast radio burst scintillation FRB 20220912A

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Research on the Evolution Mechanism of Mechanical Anisotropy During the Progressive Failure Process of Oil Shale Under Real-Time High-Temperature Conditions

SSRN

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SSRN 2024年

作者： Yang, Shaoqiang Zhang, Qinglun Yang, Dong Wang, Lei College of Engineering for safety and Emergency Management Taiyuan University of Science and Technology Taiyuan030024 China Intelligent Monitoring and Control of Coal Mine Dust Key Laboratory of Shanxi Province Taiyuan030024 China Key Laboratory of In-Situ Property-Improving Mining of Ministry of Education Taiyuan University of Technology Shanxi Taiyuan030024 China

Real-time high-temperature thermal-mechanical coupling CT scanning and a real-time high-temperature rock mechanics test system were employed to investigate the fracture structure and mechanical properties of oil shale from 20 to 600°C. The results reveal significant differences in the evolution characteristics of pore fracture structures in oil shale. Up to 400°C, under perpendicular loading to the bedding, the number of fractures remains almost constant, with the aperture initially decreasing and then increasing with temperature. Conversely, under parallel loading to the bedding, both the number and aperture of fractures continuously increase. Beyond 400°C, there is a rapid escalation in the number and aperture of the pores and fractures in both specimens with rising temperature. The temperature-induced changes in pore fractures significantly impact the mechanical properties, including the stress-strain curve, compressive strength, elastic modulus, Poisson's ratio, and fracture propagation threshold. In the temperature range of 20 to 600°C, the compressive strength, elastic modulus, and Poisson's ratio of oil shale exhibit an initial decrease followed by an increase under both perpendicular and parallel bedding loading. Specifically, the elastic modulus and Poisson's ratio reach their minimum values at 400°C. However, for Poisson's ratio, the minimum occurs at 500°C and 200°C under perpendicular and parallel bedding loading, respectively. Simultaneously, while the fracture damage stress during perpendicular bedding loading σcd-per initially increases, then decreases, and subsequently increases with temperature, the initial stress during perpendicular bedding loading σci-per, parallel bedding loading σci-par, and damage stress σcd-par decrease initially and then increase, reaching their minimum values at 400°C. These research findings provide essential data for reservoir reconstruction and cementing technology in the in-situ mining process of oil shale. © 2024, The

关键词： Elastic moduli

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An Adaptive Distributed Observer for A Class of Discrete-Time Uncertain Linear Systems over Acyclic Digraphs

An Adaptive Distributed Observer for A Class of Discrete-Tim...

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IEEE Conference on Decision and control

作者： Tao Liu Jie Huang Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology Shenzhen China Shenzhen Research Institute and Department of Mechanical and Automation Engineering The Chinese University of Hong Kong Shatin N.T. Hong Kong

This paper proposes an adaptive distributed observer for a class of discrete-time uncertain linear leader systems. The leader system is assumed to be neutrally stable with unknown parameters in the system matrix. Such a leader system can produce multi-tone sinusoidal signals with unknown frequencies, magnitudes, and phases. Under the assumption that the digraph of the communication network is a spanning tree with the leader system as the root, the proposed adaptive distributed observer is shown to be capable of estimating over the communication network not only the leader's state, but also the unknown parameters of the leader's system matrix.

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A NSGA-II with alternating direction method of multipliers mutation for solving multiobjective robust principal component analysis problem

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Journal of Computational and Theoretical Nanoscience 2016年第6期13卷 3722-3733页

作者： Yuan, Weitao Liang, Xiaodan Chen, Hanning Na, Lin Zou, Tao School of Computer Science and Software Engineering Tianjin Polytechnic University Tanjin300387 China Beijing Shenzhou Aerospace Software Technology Company Limited Beijing110000 China Laboratory of Information Service and Intelligent Control Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China

Robust Principal Component Analysis (RPCA), which is a popular parsimony model, is becoming increasingly important for researchers to do data analysis and prediction. The RPCA formulation is made of two components: sparse penalty and low rank penalty. These two competing terms are balanced with one parameter, which is essential for the effectiveness of RPCA. However, in real-world applications, the lack of data adaptive methods for choosing the right parameter hinders the popularization of RPCA. In this work, RPCA is generalized to a multiobjective optimization problem without any balancing parameter. The new model is named as Multiobjective Robust Principal Component Analysis (MRPCA). We aim to solve MRPCA via Evolutionary Algorithm. To the best knowledge of authors, this is the first attempt to use evolutionary algorithm to solve RPCA problem, which is a high dimensional convex optimization problem. Specifically, one of the popular evolutionary algorithm, NSGA-II, is tested on MRPCA problem. The curse of dimensionality is observed when the dimension of MRPCA problem increases. To handle this dimensionality problem, we introduce a novel mutation, termed as Alternating Direction Method of Multipliers mutation (ADMM mutation), that works well in high dimensional decision space. Numerical experiments show that this modified NSGA-II, which converges much faster than the standard one, can deal with the curse of dimensionality well. Furthermore, numerical image reconstruction test confirms that the reconstruction performance of our modified NSGA-II is better than the traditional proximal algorithm, which is usually used to solve RPCA problem. Copyright © 2016 American Scientific Publishers. All rights reserved.

关键词： Multiobjective optimization

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Grain boundaries in chemical-vapor-deposited atomically thin hexagonal boron nitride

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Physical Review Materials 2019年第1期3卷 014004-014004页

作者： Xibiao Ren Jichen Dong Peng Yang Jidong Li Guangyuan Lu Tianru Wu Haomin Wang Wanlin Guo Ze Zhang Feng Ding Chuanhong Jin State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University Hangzhou Zhejiang 310027 People's Republic of China Centre for Multidimensional Carbon Materials Institute for Basic Science Ulsan 44919 Republic of Korea State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai 200050 People's Republic of China State Key Laboratory of Mechanics and Control of Mechanical Structures the Key Laboratory of Intelligent Nano Materials and Devices of DoE Institute of Nano Science of Nanjing University of Aeronautics and Astronautics Nanjing 210016 China School of Materials Science and Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea

Atomically thin hexagonal boron nitride (h-BN) exhibits a wide band gap, as well as excellent thermal and chemical stability, and thus has been used in ultraviolet light emission and as building blocks for two-dimensional (2D) heterostructures. Large-area h-BN films for technical applications can now be produced by chemical vapor deposition (CVD). Unfortunately, grain boundaries (GBs) are ubiquitously introduced as a result of the coalescence of grains with different crystallographic orientations. It is well known that the properties of materials largely depend on GB structures. Here, we carried out a systematic study on the GB structures in CVD-grown polycrystalline h-BN monolayer films with a transmission electron microscope. Interestingly, most of these GBs are revealed to be formed via overlapping between neighboring grains, which are distinct from the covalently bonded GBs as commonly observed in other 2D materials. Further density functional theory calculations show that hydrogen plays an essential role in overlapping GB formation. This work provides an in-depth understanding of the microstructures and formation mechanisms of GBs in CVD-grown h-BN films, which should be informative in guiding the precisely controlled synthesis of large-area single-crystalline h-BN and other 2D materials.

关键词： Crystal growth Crystal structure Grain boundaries Honeycomb lattice Electron diffraction First-principles calculations High-resolution transmission electron microscopy

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Voltage control for Black-Start Based on Energy Storage Station and Wind Farm

Voltage Control for Black-Start Based on Energy Storage Stat...

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intelligent Power and Systems (ICIPS), International Conference on

作者： Yuanzhen Zhu Xinyu Wei Tianshu Li Yiheng Chen Ning Zhou Qiao Fang Kang Zhao Runjia Sun Shandong Smart Grid Technology Innovation Center State Grid Shandong Electric Power Company Electric Power Science Research Institute Jinan China Key Laboratory of Power System Intelligent Dispatch and Control of the Ministry of Education Jinan China

ISBN: (数字)9798331532765

ISBN: (纸本)9798331532772

Energy storage station (ESS) and wind farm (WF) have the potential to serve as a black-start sources to accelerate the power system restoration after blackout. However, the voltage security problem when start the auxiliary machines of power plants limit their reliability as black-start sources. A voltage control method is proposed for ESS and WF combined black-start sources to improve the voltage security during black-start. Firstly, the black-start process based on grid-forming ESS and WF is presented, and the voltage control framework is established. Then, a predictive control method considering the impact of active power on voltage variations is proposed, in which different optimization modes are established to obtain the active and reactive control sequences for WF and ESS. Finally, black-start simulation with Matlab/Simulink demonstrate the proposed method can improve the voltage security level when starting auxiliary machines of power plants.

关键词： Simulation Wind farms Regulation Security Reliability Voltage control Power generation Predictive control Grid forming Energy storage

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Research on Test Data Expansion Method Based on UAV Typical Index Evaluation

Research on Test Data Expansion Method Based on UAV Typical ...

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High Performance and Smart Computing (HPSC), IEEE International Conference on

作者： Huapin Geng Hongtao Ma Jiahui Tong Ning Wang Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing Electro-mechanical Engineering Institute Beijing China Beijing Xinghang Electro-mechanical Equipment Beijing China Beijing Electro-mechanical Engineering Institute Beijing China

ISBN: (数字)9798350389463

ISBN: (纸本)9798350389470

In order to scientifically and effectively evaluate the performance indexes of aircraft, the common Bayes multi-source data fusion method can comprehensively utilize a variety of information types under the condition that the decision risk is as small as possible, but there are risks such as insufficient data utilization and small sample data being “submerged” by large sample data in the fusion. This paper proposes a test data expansion method based on the combination of probability features and BP neural network model, and is verified by typical application to ensure that the sample size of multi-source data is comparable. Supplementary data not only retains the probability features of the original data, but also the sample generation has physical connotation.

关键词： Atmospheric modeling Computational modeling Neural networks Data integration Data models Performance analysis Bayes methods

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Automatic Cell Assembly by Two-fingered Microhand

Automatic Cell Assembly by Two-fingered Microhand

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2019 IEEE/RSJ International Conference on intelligent Robots and Systems (IROS)

作者： Junnan Chen Xiaoming Liu Shengnan Dong Pengyun Li Xiaoqing Tang Dan Liu Masaru Kojima Qiang Huang Tatsuo Arai Intelligent Robotics Institute School of Mechatronical Engineering Key Laboratory of Biomimetic Robots and Systems Ministry of Education Key Laboratory of Intelligent Control and Decision of Complex System Beijing Institute of Technology Beijing CHINA Department of Systems Innovation Graduate school of Engineering Science Osaka University Toyonaka Osaka Japan Global Alliance Lab The University of Electro-Communications Tokyo Japan

We have successfully achieved manipulation and assembly of microbeads having the size of 100μm diameter by hemispherical end-effectors with high stability and accuracy. The motivation of achieving assembly of actual cells lies in the great significance of it in tissue regeneration and cell analysis. Firstly, the most difficult problem we need to solve is the releasing problem caused by adhesion force. The viscosity on cell surface is much larger than the microbeads which makes cell releasing challenging. Secondly, the cell can generate its deformation, then contact area with end-effector will change during grasping process. This may influence the adhesion force and also bring problem to releasing. Thirdly, cell is much smaller, around 15μm in diameter, so we need to fabricate smaller end-effector to achieve successful manipulation and ensure the stability in the meantime. In this paper, we realize the manipulation by decreasing the adhesion forces and apply vibration to release a cell stably. We found the appropriate scale size for the end-effector is around 10μm diameter. It can not only grasp a 15μm cell but also bring little interference to the environment. As a demonstration of the proposed manipulation method, the repeated experiments were conducted to explore the dependence of adhesion force on the grasping distance, which can be helpful in the improvement of successful rate. Finally, we achieved automatic cell assembly using Hela cells.

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Chaotic synchronization in RCL-shunted Josephson junctions

Chaotic synchronization in RCL-shunted Josephson junctions

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Chinese control Conference (CCC)

作者： Pingli Lu Ying Yang Ministry of Education Key Laboratory of Complex System Intelligent Control and Decision (Beijing Institute of Technology) Beijing P. R. China Department of Mechanics and Engineering Science Peking University Beijing P. R. China

Chaotic synchronization criteria for a class of dynamical networks with each node being RCL-shunted Josephson junction is proposed in this paper. The proposed algorithms, which are established in terms of linear matrix inequalities (LMIs), guarantee the synchronized states to be global asymptotically stable. In addition, an interesting conclusion is reached that the chaotic synchronization in the coupled whole 3N-dimensional networks can be converted into that of 3-dimensional space.

关键词： Junctions Synchronization Integrated circuits Linear matrix inequalities Josephson junctions Eigenvalues and eigenfunctions Asymptotic stability

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Distributed Finite-Time Cooperative Localization for Three-Dimensional Sensor Networks

arXiv

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arXiv 2023年

作者： Wu, Jinze Zino, Lorenzo Lin, Zhiyun Rizzo, Alessandro The Department of Electronics and Telecommunications Politecnico di Torino Torino Italy Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China Peng Cheng Laboratory Shenzhen China The Institute for Invention Innovation and Entrepreneurship New York University Tandon School of Engineering BrooklynNY United States

This paper addresses the distributed localization problem for a network of sensors placed in a three-dimensional space, in which sensors are able to perform range measurements, i.e., measure the relative distance between them, and exchange information on a network structure. First, we derive a necessary and sufficient condition for node localizability using barycentric coordinates. Then, building on this theoretical result, we design a distributed localizability verification algorithm, in which we propose and employ a novel distributed finite-time algorithm for sum consensus. Finally, we develop a distributed localization algorithm based on conjugate gradient method, and we derive a theoretical guarantee on its performance, which ensures finite-time convergence to the exact position for all localizable nodes. The efficiency of our algorithm compared to the existing ones from the state-of-the-art literature is further demonstrated through numerical simulations. © 2023, CC BY.

关键词： Conjugate gradient method

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