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SSRN 2022年

作者： Qu, Wenhai Xie, Hao Shen, Danhong Wang, Zefeng Xiong, Jinbiao School of Nuclear Science and Engineering Shanghai Jiao Tong University Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

Experimental study of coherent structures downstream of a spacer grid with different inclination angles of mixing vanes in a 5×5 rod bundle was conducted by TR-PIV under four Reynolds *** coherent structures downstream of spacer grid change with several patterns. The developments of lateral time-averaged velocity, Reynolds stress, dominant frequency, integral spatial length scales and integral temporal length scales are determined by coherent structures. Smaller coherent structures are generated with Reynolds number increasing, and time-averaged velocity, Reynolds stress, St numbers, spatial and temporal length scales decrease. Larger inclination angle generates larger coherent structures, and spatial and temporal length scales increase with inclination angle increasing. The coherent structures indicate strong anisotropy of turbulent flow in rod *** experimental findings provide valuable information for understanding sub-channel mixing phenomena caused by mixing vaned spacer grids. The experimental data can be used for sub-channel mixing model developments and validations of turbulent models. © 2022, The Authors. All rights reserved.

关键词： Reynolds number

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Sensitivity analysis for dynamical response of reactor coolant system based on optimus

Sensitivity analysis for dynamical response of reactor coola...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Yanli, Yuan Xianhui, Ye Lijuan, Li Feng, Yuan Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9780791883785

The sensitivity analysis of the dynamical response of reactor coolant system to the input parameters is an important precondition for the design optimization. In this paper, the sensitivity of the dynamical loads at the nozzles of the equipment under seismic conditions is analyzed with an integrated platform called OPTIMUS, taking the stiffness of the dampers in the steam generator and the main pump as the input variables. The key parameters of the reactor system are usually different from the design value due to the calculation error, random and other uncontrollable errors in the manufacturing process and installation process. In a nuclear power project, the measured stiffness values of the dampers on the steam generator and the main pump in the manufacturer are deviated from the requirements in the equipment specification, and it is necessary to evaluate the influence of the deviation on the dynamical response analysis of the reactor system. According to the traditional method, it is necessary to establish the models of the reactor coolant system for nonlinear analysis according to the different stiffness of the dampers, and then the calculation results are compared by EXCEL. In this paper, the sensitivity analysis of output parameters which are the loads at the nozzles of the equipment to the input parameters which are the stiffness of the dampers on the steam generator and pump is realized by OPTIMUS, which is a kind of integration platform. Not only can ANSYS simulation calculations be carried out automatically on the OPTIMUS, but also the output data can be processed rapidly automatically, and the influence of manufacturing deviation of the stiffness of the dampers on the dynamical response of the reactor coolant system can be analyzed quantitatively in the above-mentioned problems, and the data support is provided for the determination of the design variables for subsequent optimization analysis. © 2020 American Society of Mechanical Engineers (ASME). All rig

关键词： Sensitivity analysis

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Crack Propagation of Ground Insulation Failure for Large Motor End-Winding Based on Electromechanical Coupling Phase Field Model

Crack Propagation of Ground Insulation Failure for Large Mot...

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IEEE Conference on Electromagnetic Field Computation

作者： Xiaobo Wu Haijun Zhang Bolong Wang Guowen Cao Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and Science Xiangyang China Xiangyang CRRC Motor Technology Co. Ltd. Xiangyang China

ISBN: (数字)9798350348958

ISBN: (纸本)9798350348965

The ground insulation is a key component for large electrical machine, which may present the crack defect after the process treatment and assembly of manufacturing. In this paper, the crack propagations of the ground insulation failure with initial crack in stator end-winding of the large motor were studied by using the coupled phase field model. In the proposed model, the coupled effects of mechanical and electrical fields on the crack propagation and the evolutions were considered by using phase field method and finite element analysis. The results in this paper may provide a new way for the research of multi-factor damage diagnosis and life prediction of motor insulation coupling.

关键词： Couplings Insulation Analytical models Computational modeling Stators Motors Finite element analysis

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Activation of Topological Defects Induces a Brittle-to-Ductile Transition in Epithelial Monolayers

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Physical Review Letters 2022年第1期128卷 018101-018101页

作者： Yixia Chen Qigan Gao Jingchen Li Fangtao Mao Ruowen Tang Hongyuan Jiang Hefei National Laboratory for Physical Science at the Microscale CAS Key Laboratory of Mechanical Behavior and Design of Materials CAS Center for Excellence in Complex System Mechanics Department of Modern Mechanics University of Science and Technology of China Hefei Anhui 230026 China

Epithelial monolayers are subjected to various mechanical forces, such as stretching, shearing, and compression. Thus, its mechanical response to external loadings is essential for its biological functions. However, the mechanism of the fracture failure of the epithelial monolayer remains poorly understood. Here, by introducing a new type of topological transition, i.e., detach transition or T4 transition, we develop a modified cellular vertex model to investigate the rupture of the cell monolayer. Interestingly, we find a brittle-to-ductile transition in epithelial monolayers, which is controlled by the mechanical properties of single cells and cell-cell contacts. We reveal that the external loadings can activate cell rearrangement in ductile cell monolayers. The plastic deformation results from the nucleation and propagation of “pentagon-heptagon defects” in analogy with the topological defects commonly seen in 2D materials. By using a simplified four-cell model, we further demonstrate that the brittle-to-ductile transition is induced by the competition between cell rearrangement and cell detachment. Our work provides a new theoretical framework to study the rupture of living tissues and may have important implications for many other biological processes, such as wound healing and tissue morphogenesis.

关键词： Cell aggregation Cell mechanics Epithelial cells Tissues

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High-density/efficient surface active sites on modified separators to boost Li-S batteries via atomic Co^(3+)-Se termination

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Nano Research 2022年第8期15卷 7199-7208页

作者： Shujie Liu Xiaofei Liu Manfang Chen Dong Wang Xin Ge Wei Zhang Xiyang Wang Chunhui Wang Tingting Qin Haozhe Qin Liang Qiao Dan Zhang Xing Ou Weitao Zheng Key Laboratory of Automobile Materials of MOE School of Materials Science and Engineeringand Electron Microscopy Centerand International Center of Future ScienceJilin UniversityChangchun 130013China Key Laboratory of Materials Design and Quantum Simulation College of ScienceChangchun UniversityChangchun 130022China National Base for International Science&Technology Cooperation School of ChemistryXiangtan UniversityXiangtan 411105China State Key Laboratory of Chem/Bio-Sensing and Chemometrics Advanced Catalytic Engineering Research Center of the Ministry of EducationCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Department of Mechanical and Mechatronics Engineering University of WaterlooWaterlooN2L 3G1Canada School of Metallurgy and Environment Central South UniversityChangsha 410083China

Various and critical electrocatalytic processes are involved during the redox reactions in the Li-S batteries,which extremely depend on the surface structure and chemical ***,single-atom concept unlocks a route to maximize the use of surface-active atoms,however,further increasing the density of active site is still strictly limited by the inherent structure that single-atoms are only highly-dispersed on ***,we provide a viewpoint that an elaborate facet design with singlecrystalline structure engineering can harvest high-density surface active sites,which can significantly boost the electrocatalyst performance for excellent Li-S ***,the single-crystal CoSe_(2)(scCS)exhibits three-types of terminated(011)facet,efficiently obtaining the surface with a high-rich Co^(3+)–Se bond termination,in contrast with lots of surface grain boundaries and dangling bonds in polycrystalline CoSe_(2).Surprisingly,the surface active sites concentration can reach more than 69%.As anticipated,it can provide high-density and high-efficient active sites,enormously suppressing the shuttle effect and improving the reaction kinetics via accelerating the conversion and deposition of polysulfides and *** surface lattice strategy with element terminated mode is a promising approach for designing electrocatalyst effect-based energy system,not merely for Li-S batteries.

关键词： high-density surface active sites Co^(3+)-Se covalent bond atomic element terminated Li-S batteries single-crystalline strategy

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Modal Analysis of Lead-Bismuth Eutectic Flow in a Single Wire-Wrap Rod Channel

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SSRN 2022年

作者： Zhao, Xielin Cheng, Qian Yu, Xiaofei Huang, Qian Zhang, Ke Feng, Zhipeng Zhou, Jinxiong State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace Xi'an Jiaotong University Xi'An710049 China Key Laboratory of Science and Technology on Reactor System Design Technology Nuclear Power Institute of China Chengdu610200 China

The thermal-hydraulics as well as flow-induced vibration of wire-wrapped rod bundles calls for accurate and efficient liquid metal flow simulation and prediction, yet it remains a challenge due to the complex geometries and high Reynolds number flow in wire-wrapped rod channel. Previous efforts towards this goal exclusively adopts full-order modeling (FOM), which is prohibitively computation-intensive. This work reports the first reference on modal analysis of the turbulent lead-bismuth eutectic (LBE) flow in a single wire-wrapped rod channel by a data-driven dynamic mode decomposition (DMD) method. The spatio-temporal data of fluid velocities and pressure were modelled and collected by using the Reynolds-averaged NavierStokes equations (RANS) approach with stress-omega RSM turbulence model. Model analysis was performed over the snapshot matrices and DMD modes and corresponding eigenvalues were calculated. The DMD modes and eigenvalues were then used to construct a reducedorder modeling (ROM) system for fast fluid field reconstruction and short-term forecasting. The correctness and feasibility of the method was demonstrated and compared with groundtruth CFD simulation results. Our method offers a fast and reliable approach for ROM of turbulent flow in wire-wrapped rod fuel assemblies. We publicize all the data and codes via https://***/XJTU-Zhou-group/Wire-wrapped-fuel-pin-CFD-DMD. © 2022, The Authors. All rights reserved.

关键词： Dynamic mode decomposition

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Distributed Time-Varying Optimization with Equality Constraints

Distributed Time-Varying Optimization with Equality Constrai...

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International Conference on Control and Automation (ICCA)

作者： Zheng Yang Ji Ma Xiang Xu Department of Automation Xiamen University Xiamen Fujian China Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

ISBN: (数字)9798350354409

ISBN: (纸本)9798350354416

In this paper, we consider the distributed time-varying optimization problem with coupled equality constraints over a connected undirected network. To address this issue, we design a novel distributed constraint optimization algorithm, and establish its ISS stability with external disturbances and tracking errors as the input and state, respectively. Moreover, the obtained result includes distributed constrained optimization with static objective functions as a special case. In comparison to existing relevant works, the proposed algorithm demonstrates exponential convergence for cases involving static objective functions. Finally, the theoretical results are validated via a numerical example.

关键词： Constraint optimization Automation Linear programming Trajectory Optimization Numerical stability Convergence

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Near-field communications:characteristics,technologies,and engineering

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Frontiers of Information technology & Electronic Engineering 2024年第12期25卷 1580-1626页

作者： Yajun ZHAO Linglong DAI Jianhua ZHANG Ran JI Mengnan JIAN Hao XUE Hongkang YU Yunqi SUN Yu LU Zidong WU Zhuo XU Jinke LI Haiyang MIAO Zhiqiang YUAN Pan TANG Jiayu SHEN Tierui GONG Haixia LIU Jiaqi HAN Qiang FENG Zhi CHEN Lingxiang LI Gang YANG Yong ZENG Cunhua PAN Wang LIU Kangda ZHI Weidong HU Yuanwei LIU Xidong MU Chau YUEN Mérouane DEBBAH Chongwen HUANG Long LI Ping ZHANG State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen 518055China ZTE Corporation Beijing 100192China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310007China Key Laboratory of High Speed Circuit Design and EMC of Ministry of Education School of Electronic EngineeringXidian UniversityXi’an 710071China Collaborative Innovation Center of Information Sensing and Understanding Xidian UniversityXi’an 710071China National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China Purple Mountain Laboratories Nanjing 211111China School of Electrical Engineering and Computer Science Technical University of BerlinBerlin 10623Germany School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina Centre for Wireless Innovation(CWI) School of ElectronicsElectrical Engineering and Computer ScienceQueen’s University BelfastBelfast BT39DTUK School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore KU 6G Research Center Khalifa University of Science and TechnologyAbu DhabiUnited Arab Emirates

Near-field technology is increasingly recognized due to its transformative potential in communication systems,establishing it as a critical enabler for sixth-generation(6G)telecommunication *** paper presents a comprehensive survey of recent advancements in near-field technology ***,we explore the near-field propagation fundamentals by detailing definitions,transmission characteristics,and performance ***,we investigate various near-field channel models—deterministic,stochastic,and electromagnetic information theory based models,and review the latest progress in near-field channel testing,highlighting practical performance and *** evolving channel models,traditional mechanisms such as channel estimation,beamtraining,and codebook design require redesign and optimization to align with near-field propagation *** then introduce innovative beam designs enabled by near-field technologies,focusing on non-diffractive beams(such as Bessel and Airy)and orbital angular momentum(OAM)beams,addressing both hardware architectures and signal processing frameworks,showcasing their revolutionary potential in near-field communication ***,we highlight progress in both engineering and standardization,covering the primary 6G spectrum allocation,enabling technologies for near-field propagation,and network deployment ***,we conclude by identifying promising future research directions for near-field technology development that could significantly impact system *** comprehensive review provides a detailed understanding of the current state and potential of near-field technologies.

关键词： 6G Near-field technology Channel model Codebook Non-diffractive beams Orbital angular momentum Engineering and standardization

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Experimental Study on the Characteristics of Annular Fluid Film in a Locally Deformed Narrow Rectangular Channel

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SSRN 2024年

作者： Wang, Fenze Ren, Quanyao Liu, Haidong Xiao, Yi Chen, Deqi Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing400044 China Department of Nuclear Engineering and Technology School of Energy and Power Engineering Chongqing University Chongqing400044 China Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China Liangjiang International College Chongqing University of Technology Chongqing401135 China Chongqing Research Institute of HIT Chongqing401151 China School of Flight Technology Civil Aviation Flight University of China Sichuan618307 China China

The study of the characteristics of the annular flow film in the narrow rectangular channel under the localized deformation can provide a research basis for the heat and mass transfer and the hydrodynamic characteristics of the locally deformed narrow flow channel. In this study, the annular flow liquid film characterization experiments are carried out in a narrow rectangular channel without local deformation, ellipsoidal deformation and pillow-shaped deformation, and different annular flow liquid film parameters liquid film thickness, disturbance wave height, and disturbance wave wavelength are obtained by high-speed camera acquisition system and intelligent image processing technology. Analyze the effects of flow conditions and local deformation on the liquid film parameters of each annular flow. Local deformation impact factor functions for liquid film thickness, disturbance wave height, and disturbance wave wavelength are obtained. The error of the impact factor function is within ±30%. © 2024, The Authors. All rights reserved.

关键词： Liquid films

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Like an Ophthalmologist: Dynamic Selection Driven Multi-View Learning for Diabetic Retinopathy Grading 39

Like an Ophthalmologist: Dynamic Selection Driven Multi-View...

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39th Annual AAAI Conference on Artificial Intelligence, AAAI 2025

作者： Luo, Xiaoling Xu, Qihao Wu, Huisi Liu, Chengliang Lai, Zhihui Shen, Linlin Computer Vision Institute College of Computer Science and Software Engineering Shenzhen University Shenzhen China Shenzhen Key Laboratory of Visual Object Detection and Recognition Harbin Institute of Technology Shenzhen China Department of Computer Science and Engineering Hong Kong University of Science and Technology Hong Kong National Engineering Laboratory for Big Data System Computing Technology Shenzhen University Shenzhen China Guangdong Provincial Key Laboratory of Intelligent Information Processing China

ISBN: (纸本)157735897X

Diabetic retinopathy (DR), with its large patient population, has become a formidable threat to human visual health. In the clinical diagnosis of DR, multi-view fundus images are considered to be more suitable for DR diagnosis because of the wide coverage of the field of view. Therefore, different from the previous single-view DR grading methods, we design a dynamic selection-driven multi-view DR grading method to fit clinical scenarios better. Since lesion information plays a key role in DR diagnosis, previous methods usually boost the model performance by enhancing the lesion feature. However, during the actual diagnosis, ophthalmologists not only focus on the crucial parts, but also exclude irrelevant features to ensure the accuracy of judgment. To this end, we introduce the idea of dynamic selection and design a series of selection mechanisms from fine granularity to coarse granularity. In this work, we first introduce an Ophthalmic Image Reader (OIR) agent to provide the model with pixel-level prompts of suspected lesion areas. Moreover, we design a Multi-View Token Selection Module (MVTSM) that prunes redundant feature tokens and dynamically selects key information. In the final decision stage, we dynamically fuse multi-view features through the novel Multi-View Mixture of Experts Module (MVMoEM), to enhance key views and reduce the impact of conflicting views. Extensive experiments on a large multi-view fundus image dataset with 34,452 images prove that our method performs favorably against state-of-the-art models. Copyright © 2025, Association for the Advancement of Artificial Intelligence (***). All rights reserved.

关键词： Ophthalmology

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