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Flatbands and Emergent Ferromagnetic Ordering in Fe3Sn2 Kagome Lattices

Physical Review Letters 2018年第9期121卷 096401-096401页

作者： Zhiyong Lin Jin-Ho Choi Qiang Zhang Wei Qin Seho Yi Pengdong Wang Lin Li Yifan Wang Hui Zhang Zhe Sun Laiming Wei Shengbai Zhang Tengfei Guo Qingyou Lu Jun-Hyung Cho Changgan Zeng Zhenyu Zhang International Center for Quantum Design of Functional Materials (ICQD) Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 China CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics University of Science and Technology of China Hefei Anhui 230026 China Department of Physics and HYU-HPSTAR-CIS High Pressure Research Center Hanyang University 17 Haengdang-Dong SeongDong-Ku Seoul 133-791 Korea National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei Anhui 230029 China Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory and Hefei Science Center Chinese Academy of Sciences Hefei 230031 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China

A flatband representing a highly degenerate and dispersionless manifold state of electrons may offer unique opportunities for the emergence of exotic quantum phases. To date, definitive experimental demonstrations of flatbands remain to be accomplished in realistic materials. Here, we present the first experimental observation of a striking flatband near the Fermi level in the layered Fe3Sn2 crystal consisting of two Fe kagome lattices separated by a Sn spacing layer. The band flatness is attributed to the local destructive interferences of Bloch wave functions within the kagome lattices, as confirmed through theoretical calculations and modelings. We also establish high-temperature ferromagnetic ordering in the system and interpret the observed collective phenomenon as a consequence of the synergetic effect of electron correlation and the peculiar lattice geometry. Specifically, local spin moments formed by intramolecular exchange interaction are ferromagnetically coupled through a unique network of the hexagonal units in the kagome lattice. Our findings have important implications to exploit emergent flat-band physics in special lattice geometries.

关键词： Electronic structure Ferromagnetism Kagome lattice Angle-resolved photoemission spectroscopy Density functional theory First-principles calculations Magnetization measurements Scanning tunneling microscopy Scanning tunneling spectroscopy Tight-binding model

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Fluoride-Salt-Cooled High-Temperature reactor: An Integrated Nuclear-Based Energy Production and Conversion system

SSRN

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SSRN 2023年

作者： Zhang, Dalin Li, Xinyu Jiang, Dianqiang Zhou, Xingguang Lv, Xindi Yun, Shichang Wu, Wenqiang He, Xuanang Li, Haoyang Min, Xin Chen, Kailong Tian, Wenxi Qiu, Suizheng Su, G.H. Zhao, Quanbin Fu, Yao Tang, Chuntao Zhuo, Wenbin Li, Jinggang Zuo, Jiaxu State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China Shanghai Nuclear Engineering Research & Design Institute CO. LTD. Shanghai200233 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China China Nuclear Power Technology Research Institute Guangdong Shenzhen518000 China Nuclear and Radiation Safety Center Ministry of Ecology and Environment People's Republic of China Beijing100082 China

Based on the analysis of energy structure and the development trends of advanced nuclear energy technology, combining the complementary advantages of nuclear energy and other energy sources in China, the Fluoride-salt-cooled High-temperature reactor(FuSTAR) system has been proposed. FuSTAR system is designed to address production capacity issues in areas with energy shortages or resource concentration and can be combined with high-temperature process heat to achieve high-value-added processes such as hydrogen production. In this paper, the Tri-structural isotropic fuel combined with helical cruciform elements has been studied in detail on the neutron physics and thermal-hydraulic properties, and the flow and heat transfer experiment is carried out for the first time. The multilayer nonlinear programming method has been applied to the design of thermal transport systems. Then the optimal parameters and configuration of the thermoelectric conversion system are obtained by the superstructure optimization method. The inherent safety of FuSTAR is demonstrated through deterministic safety analysis. In addition, the iodine-sulfur cycle technology and the characteristics of tritium production are also analyzed. This study highlights the significant potential of integrating nuclear energy with other energy sources in an optimized energy-production system. © 2023, The Authors. All rights reserved.

关键词： Nonlinear programming

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MRPB 1.0: A Unified Benchmark for the Evaluation of Mobile Robot Local Planning Approaches

MRPB 1.0: A Unified Benchmark for the Evaluation of Mobile R...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Jian Wen Xuebo Zhang Qingchen Bi Zhangchao Pan Yanghe Feng Jing Yuan Yongchun Fang Institute of Robotics and Automatic Information System College of Artificial Intelligence Nankai University Tianjin China Tianjin Key Laboratory of Intelligent Robotics Nankai University Tianjin China School of Marine Science and Technology Northwestern Polytechnical University Xi’an China Faculty of Robot Science and Engineering Northeastern University Shenyang China College of Systems Engineering National University of Defense Technology Changsha China

Local planning is one of the key technologies for mobile robots to achieve full autonomy and has been widely investigated. To evaluate mobile robot local planning approaches in a unified and comprehensive way, a mobile robot local planning benchmark called MRPB 1.0 is newly proposed in this paper. The benchmark facilitates both motion planning researchers who want to compare the performance of a new local planner relative to many other state-of-the-art approaches as well as end users in the mobile robotics industry who want to select a local planner that performs best on some problems of interest. We elaborately design various simulation scenarios to challenge the applicability of local planners, including large-scale, partially unknown, and dynamic complex environments. Furthermore, three types of principled evaluation metrics are carefully designed to quantitatively evaluate the performance of local planners, wherein the safety, efficiency, and smoothness of motions are comprehensively considered. We present the application of the proposed benchmark in two popular open-source local planners to show the practicality of the benchmark. In addition, some insights and guidelines about the design and selection of local planners are also provided. The benchmark website [1] contains all data of the designed simulation scenarios, detailed descriptions of these scenarios, and example code.

关键词： Measurement Industries Service robots Dynamics Benchmark testing Planning Safety

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Boosting weather forecast via generative superensemble

arXiv

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arXiv 2024年

作者： Nai, Congyi Chen, Xi Yang, Shangshang Liang, Yuan Xiao, Ziniu Pan, Baoxiang Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Science Beijing China Institute of Atmospheric Physics Chinese Academy of Science Beijing China School of Engineering and Design Technical University of Munich Munich Germany Potsdam Institute for Climate Impact Research Potsdam Germany TianJi Weather Science and Technology Company Beijing China

Accurate weather forecasting is essential for socioeconomic activities. While data-driven forecasting demonstrates superior predictive capabilities over traditional Numerical Weather Prediction (NWP) with reduced computational demands, its deterministic nature and limited advantages over physics-based ensemble predictions restrict operational applications. We introduce the generative ensemble prediction system (GenEPS) framework to address these limitations by randomizing and mitigating both random errors and systematic biases. GenEPS provides a plug-and-play ensemble forecasting capability for deterministic models to eliminate random errors, while incorporating cross-model integration for cross-model ensembles to address systematic biases. The framework culminates in a superensemble approach utilizing all available data-driven models to further minimize systematic biases. GenEPS achieves an Anomaly Correlation Coefficient (ACC) of 0.679 for 500hPa geopotential (Z500), exceeding the ECMWF Ensemble Prediction system’s (ENS) ACC of 0.646. Integration of the ECMWF ensemble mean further improves the ACC to 0.683. The framework also enhances extreme event representation and produces energy spectra more consistent with ERA5 reanalysis. GenEPS establishes a new paradigm in ensemble forecasting by enabling the integration of multiple data-driven models into a high-performing super-ensemble system. © 2024, CC BY-NC-SA.

关键词： Prediction models

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The 5th International Conference on Biomedical Engineering and Biotechnology (ICBEB 2016) Abstracts

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BMC MEDICAL IMAGING 2016年第SUPPL 1期16卷 65-65页

作者： [Anonymous] Department of MRI Shandong Medical Imaging Research Institute Affiliated to Shandong University Jinan Shandong 250021 People’s Republic of China Department of Interventional Radiology Shandong Provincial Hospital Affiliated to Shandong University Jinan Shandong 250021 People’s Republic of China College of Information Science and Technology Engr. Research Center of Digitized Textile & Fashion Tech. for Ministry of Education Donghua University Shanghai 201620 China Intelligent multimedia information processing Lab College of Software Northeastern University Shenyang Liaoning Province 110004 China Institute of Biomedical and Health Engineering Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China School of Computer Science and Technology Nanjing Normal University Nanjing China Department of Electrical Engineering The City College of New York CUNY New York USA Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing Nanjing China School of Electronic Science and Engineering Nanjing University Nanjing Jiangsu 210046 China College of Engineering Nanyang Technological University Singapore 639798 Singapore School of Electronic Information Shanghai Dianji University Shanghai China School of Natural Sciences and Mathematics Shepherd University Shepherdstown WV 25443 USA Davis College of Agriculture Natural Resources and Design West Virginia University Morgantown WV 26505 USA State Key Laboratory of Millimeter Waves Southeast University Nanjing 210096 China Center of Medical Physics and Technology Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei China College of Agricultural and Life Sciences University of Florida Gainesville FL 32611 USA Courant Institute of Mathematical Sciences New York University New York NY 10012 USA Translational Imaging Division & MRI Unit Columbia University and New York State Psychiatric Institute New York NY 10032 USA Guangxi Key Laboratory of Manufacturing System & Adv

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Scaling analysis and SE simulation of the tilted cylinder-interface capillary interaction

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IOP Conference Series: Materials science and Engineering 2018年第1期372卷

作者： S Q Gao X Y Zhang Y H Zhou National Key Laboratory of Science and Technology on Reactor System Design Technology Nuclear Power Institute of China Chengdu 610041 China Department of Mechanics and Engineering Sciences College of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 China

The capillary interaction induced by a tilted cylinder and interface is the basic configuration of many complex systems, such as micro-pillar arrays clustering, super-hydrophobicity of hairy surface, water-walking insects, and fiber aggregation. We systematically analyzed the scaling laws of tilt angle, contact angle, and cylinder radius on the contact line shape by SE simulation and experiment. The following in-depth analysis of the characteristic parameters (shift, stretch and distortion) of the deformed contact lines reveals the self-similar shape of contact line. Then a general capillary force scaling law is proposed to incredibly grasp all the simulated and experimental data by a quite straightforward ellipse approximation approach.

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Stackelberg-game based distributed energy-aware resource allocation in device-to-device communications

Stackelberg-game based distributed energy-aware resource all...

引用

International Conference on Communication systems

作者： Zhenyu Zhou Mianxiong Dong Kaoru Ota Bo Gu Takuro Sato State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China National Institute of Information and Communications Technology Kyoto Japan Department of Information and Electric Engineering Muroran Institute of Technology Muroran Japan Department of Computer Science and Communications Engineering Waseda University Tokyo Japan

ISBN: (纸本)9781479958337

Despite the numerous benefits brought by device-to-device (D2D) communications, user equipments (UEs) are typically handheld devices with limited battery life and can quickly run out of battery if power consumption is ignored in the system design. Compared to previous works that have not taken power consumption into consideration, we model the utility function as a weighted sum of achievable transmission rate, power consumption, and interference revenue (or cost) based on multi-objective optimization (MOO) methods. The resource allocation process is modeled as a two-stage Stackelberg game with transmission power and quality of service (QoS) constraints, in which cellular UEs are game leaders who charges D2D UEs for reusing channels, and D2D UEs are game followers who buy channel resources from cellular UEs. Simulation results show the effectiveness of the proposed algorithm and how the system parameters affect the pricing and transmission power strategies.

关键词： Interference Power demand Resource management Games Quality of service Transmitters Educational institutions

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Estimation of Anthropogenic Heat from Buildings Based on Various Data Sources in Singapore

SSRN

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SSRN 2022年

作者： He, Wenhui Li, Xian-Xiang Zhang, Xiaohu Yin, Tiangang Norford, Leslie K. Yuan, Chao School of Atmospheric Sciences Key Laboratory of Tropical Atmosphere-Ocean System Ministry of Education Sun Yat-sen University Guangdong Zhuhai China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai China Department of Urban Planning and Design The University of Hong Kong Hong Kong Earth System Science Interdisciplinary Center University of Maryland College ParkMD United States Department of Architecture Massachusetts Institute of Technology CambridgeMA United States Center for Environmental Sensing and Modeling Singapore-MIT Alliance for Research and Technology Singapore Department of Architecture National University of Singapore Singapore

Heat released from the energy consumption in buildings (QB) is an important component of anthropogenic heat, which is a major contribution to the urban heat island (UHI) phenomenon. However, it is still a challenge to integrate all the available data to improve the estimation of QB due to inconsistence among multiple data sources. This paper presents a solution to estimate the anthropogenic heat from buildings in Singapore by classifying the buildings into the electricity consumption sectors based on random forest classification model using multiple data sources. The classification model achieves a cross validation accuracy score of 95% by using building use type, land use type of land parcel where the building stands, location and area as predictors. Based on the classification result, the daily average QB from the commercial buildings (CS), Housing and Development Board (HDB) apartments, private apartments and condominiums (AC), and landed properties (LP) were estimated to be 12.1, 4.4, 3.2 and 1.1 W m-2 on a 200 m-by-200 m grid, respectively. QB was approximately 9% of the net all-wave radiation in Singapore in 2015. Our approach can serve as a useful tool for integrating dataset from different sources with inconsistent categorisations. © 2022, The Authors. All rights reserved.

关键词： Energy utilization

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Reshaping the ISAC Tradeoff Under OFDM Signaling: A Probabilistic Constellation Shaping Approach

arXiv

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arXiv 2023年

作者： Du, Zhen Liu, Fan Xiong, Yifeng Han, Tony Xiao Eldar, Yonina C. Jin, Shi The School of Electronic and Information Engineering Nanjing University of Information Science and Technology Nanjing China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China The School of Information and Electronic Engineering Beijing University of Posts and Telecommunications Beijing China Huawei Technologies Co. Ltd Shenzhen China The Faculty of Mathematics and Computer Science Weizmann Institute of Science Rehovot Israel National Mobile Communications Research Laboratory Southeast University Nanjing210096 China

Integrated sensing and communications is regarded as a key enabling technology in the sixth generation networks, where a unified waveform, such as orthogonal frequency division multiplexing (OFDM) signal, is adopted to facilitate both sensing and communications (S&C). However, the random communication data embedded in the OFDM signal results in severe variability in the sidelobes of its ambiguity function (AF), which leads to missed detection of weak targets and false detection of ghost targets, thereby impairing the sensing performance. Therefore, balancing between preserving communication capability (i.e., the randomness) while improving sensing performance remains a challenging task. To cope with this issue, we characterize the random AF of OFDM communication signals, and demonstrate that the AF variance is determined by the fourth-moment of the constellation amplitudes. Subsequently, we propose an optimal probabilistic constellation shaping (PCS) approach by maximizing the achievable information rate (AIR) under the fourth-moment, power and probability constraints, where the optimal input distribution may be numerically specified through a modified Blahut-Arimoto algorithm. To reduce the computational overheads, we further propose a heuristic PCS approach by actively controlling the value of the fourth-moment, without involving the communication metric in the optimization model, despite that the AIR is passively scaled with the variation of the input distribution. Numerical results show that both approaches strike a scalable performance tradeoff between S&C, where the superiority of the PCS-enabled constellations over conventional uniform constellations is also verified. Notably, the heuristic approach achieves very close performance to the optimal counterpart, at a much lower computational complexity. Copyright © 2023, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

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design of a new solution for the wheeled hopping robot

Design of a new solution for the wheeled hopping robot

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UKACC International Conference on Control (CONTROL)

作者： Jingjing Liu Hongbo Wang Hongnian Yu Lili Zhang Luige Vladareanu Adrian Bruja Gal I. Alexandru Parallel Robot and Mechatronic System Laboratory of Hebei Province Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao China College of Electrical Engineering Yanshan University Qinhuangdao China School of Design Engineering and Computing Bournemouth University Poole UK Robotics and Mechatronic Department Institute of Solid Mechanics Bucharest Romania

In recent years many researchers are trying to combine wheeled movement with legged movement or hopping movement to strengthen the robots adaptability to environment. Hybrid robots are playing a more and more important role in our modern life. However, their controls are mostly complicated. So in this paper we present a new solution for the wheeled hopping robot. Based on the mechanical design, this robot has two movement modes: wheeled and hopping movement mode. While the center of gravity of the mechanism is under the wheels center, the wheeled hopping robot which is like a tumbler can keep its stability even when the wheels' velocity is zero. In this paper, we firstly introduce the description and design of the wheeled hopping robot. Then we explain how to choose the robot parameters and lastly we describe, how the robot through hopping, successfully traverses obstacles and ditches.

关键词： Mobile robots Shafts Wheels Springs Robot kinematics Force

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