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SSRN 2022年

作者： Wang, Zhiwei Duan, Zhongdi He, Yanping Huang, Chao Yuan, Yuchao Liu, Shiwen Li, Mingzhi State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China School of Naval Architecture Ocean & Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Institute of Marine Equipment Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The investigation of condensation-induced water hammer (CIWH) under ocean conditions is crucial to the system safety of the offshore floating nuclear plants (OFNPs). This paper establishes a CIWH numerical model under rolling conditions based on the computational fluid dynamics (CFD) code combined with user-defined functions (UDF). First, the numerical model is verified by published experimental data. Then, the transient behaviors of CIWH events under various rolling parameters are numerically investigated. The results show that the rolling motion causes a significant steam slug and enhances the steam-subcooled water contact area, which promotes the average condensation rate. The average condensation rate increases with an increase in rolling angle, decreases with an increase in rolling period. Due to the larger average condensation rate and reverse flow caused by rolling motion, the pressure peak generated by the CIWH significantly increases compared to static conditions. Similarly, the pressure peak increases as rolling angle increases, decreases as rolling period increase. Moreover, the pressure peak is proportional to steam inlet velocity, and the location of the pressure peak gradually moves back to the outlet direction as the steam velocity increases. These qualitative conclusions are useful to understand the effects of rolling motion on the CIWH and provide a reference for the CIWH simulations. © 2022, The Authors. All rights reserved.

关键词： Condensation

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Effect of Rolling Motion on Transient Behaviors of Condensation-Induced Water Hammer in an Equal-Height-Difference Passive Heat Removal system

SSRN

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SSRN 2022年

作者： Duan, Zhongdi Wang, Zhiwei He, Yanping Huang, Chao Li, Mingzhi Yuan, Yuchao Liu, Shiwen State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China School of Naval Architecture Ocean & Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Institute of Marine Equipment Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The investigation of condensation-induced water hammer (CIWH) under ocean conditions is vital to the system safety of the offshore floating nuclear plants (OFNPs). This paper establishes a CIWH numerical model under rolling conditions based on the computational fluid dynamics (CFD) code combined with user-defined functions (UDF). First, the numerical model is validated with the experimental data. Then, the transient behaviors of the CIWH under various rolling parameters are numerically investigated. The results show that the rolling motion causes a significant steam slug and increases the steam-subcooled water contact area, which promotes the average condensation rate. The average condensation rate increases as the rolling angle increases and the rolling period decreases. Due to the larger average condensation rate and reverse flow induced by rolling motion, the pressure peak generated by the CIWH significantly increases compared to static conditions. Similarly, the pressure peak increases as the rolling angle increases and the rolling period decrease. Moreover, the pressure peak is proportional to the steam inlet velocity, and the location of the pressure peak gradually moves back to the outlet direction as the steam inlet velocity increases. These qualitative conclusions may serve as a reference for the CIWH simulations under ocean conditions. © 2022, The Authors. All rights reserved.

关键词： Condensation

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A Train Cooperative Operation Optimization Method Considering Passenger Comfort based on Reinforcement Learning 11

A Train Cooperative Operation Optimization Method Considerin...

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11th IEEE Data Driven Control and Learning systems Conference, DDCLS 2022

作者： Wang, Xingguo Wu, Yue Huang, Deqing Zhu, Lei Lu, Zheng He, Yan Institute of System Science and Technology School of Electrical Engineering Southwest Jiaotong University Chengdu611756 China Southwest Jiaotong University Key Laboratory of Advanced Energy Traction Comprehensive Energy Saving Railway Industry Chengdu610031 China School of Computing and Artificial Intelligence Southwest Jiaotong University Chengdu611756 China School of Design Arts Southwest Jiaotong University Chengdu610031 China

ISBN: (数字)9781665496759

ISBN: (纸本)9781665496759

This paper mainly focuses on the high-speed train cooperative operation problem, considering passenger comfort. To solve this problem, a speed curve optimization method based on Reinforcement Learning algorithm is proposed. First, according to the train dynamics system, we build the speed curve optimization object. For realizing the train cooperative operation and increasing the passenger comfort, trains distance constraint and jerk rate constraint are fully considered in formulating reward function. And then, agent of Twin Delayed Deep Deterministic Policy Gradient (TD3) is established. Based on TD3 algorithm, two groups of Q-value networks and one group of action action networks have the same structure, different initial values and update rates respectively, which improves the stability and convergence speed of the algorithm. After the training. The Agent can generate a desirable speed curve of train based on constraints of vehicle output and jerk rate under cooperative operation. © 2022 IEEE.

关键词： Speed

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Two points are enough

arXiv

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arXiv 2024年

作者： Liu, Hao Zhao, Yanbin Zheng, Huarong Fan, Xiulin Deng, Zhihua Chen, Mengchi Wang, Xingkai Liu, Zhiyang Lu, Jianguo Chen, Jian State Key Laboratory of Fluid Power Components and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou China Ocean College Zhejiang University Hangzhou China State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and Engineering Zhejiang University Hangzhou China Nanyang Technological University Singapore School of Control Science and Engineering Zhejiang University Hangzhou China School of Materials Science and Engineering Tianjin University Tianjin China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

Prognosis and diagnosis play an important role in accelerating the development of lithium-ion batteries, as well as reliable and long-life operation. In this work, we answer an important question: What is the minimum amount of data required to extract features for accurate battery prognosis and diagnosis? Based on the first principle, we successfully extracted the best two-point feature (BTPF) for accurate battery prognosis and diagnosis using the fewest data points (only two) and the simplest feature selection method (Pearson correlation coefficient). The BTPF extraction method is tested on 820 cells from 6 open-source datasets (covering five different chemistry types, seven manufacturers, and three data types). It achieves comparable accuracy to state-of-the-art features in both prognosis and diagnosis tasks. This work challenges the cognition of existing studies on the difficulty of battery prognosis and diagnosis tasks, subverts the fixed pattern of establishing prognosis and diagnosis methods for complex dynamic systems through deliberate feature engineering, highlights the promise of data-driven methods for field battery prognosis and diagnosis applications, and provides a new benchmark for future studies. Copyright © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Data-driven modeling fast-slow coupling delayed dynamics using noisy data and sparse enhancement

Data-driven modeling fast-slow coupling delayed dynamics usi...

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International Conference on Industrial Artificial Intelligence (IAI)

作者： Huifang Tang Yuqiang Wu Yingming Dong Cheng Cheng Xiuting Li College of Science Huazhong Agricultural University Wuhan China School of Artificial Intelligence and Automation Huazhong University of Science and Techonology Wuhan China Yunnan Key Laboratory of Mechatronics Applied Technology Yunnan Mechanical Research and Design Institute of Machinery Research Institute Group Yunnan China Autonomous Intelligent Unmanned System Engineering Research Center Ministry of Education of China Huazhong University of Science and Technology Wuhan China

In this work, we focus on fast-slow delayed dynamical systems, which are usually described by coupled delayed differential equations with two-time scales. The purpose of this article is to propose a data-driven discovery method to identify the fast-slow delayed differential equations from noisy measurements. The proposed method blends delay dictionary-based sparse identification of nonlinear dynamics (SINDy) framework and a fixed interval sampling strategy. Specifically, we leverage the SINDy methodology to describe the fast-slow delayed differential equations by a few active terms of a large dictionary containing the delay terms and many candidate nonlinear basis functions. To identify the active terms and the corresponding coefficients, a sequential thresholded re-weighted ℓ 2 least squares algorithm is used to solve the resulting sparse regression problem to enhance the sparsity. Once a sparse model with fixed delay is selected, the proposed method further estimates the delayed time by calculating the reconstruction error from the sparse model until the one that makes the reconstruction error minimum. We verify the effectiveness of the proposed method with several classical fast-slow coupling delayed systems. The experimental results show that the proposed method can well automate the fast-slow delayed differential equations from noisy data and the delayed terms also can be detected accurately.

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Link Budget Calculation for LoRa-band Remoting Sensing Satellite

Link Budget Calculation for LoRa-band Remoting Sensing Satel...

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IEEE International Symposium on Electromagnetic Compatibility (EMC-Beijing)

作者： Shurui Wang Xiang Zhang Xiaojun Hao Shuaige Gong Chong Li Qian Xu Lei Xing College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing China College of Mechanical Engineering (Aircraft design and engineering) Nanjing University of Science and Technology Nanjing China State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System (CEMEE) Luoyang China

Small satellites are increasingly attracting the attention of the industry for its many aspects of advantages. We proposed a communication subsystem for commercial remote sensing satellite. The interface between the communication system and other modules on the satellite and the communication protocol are briefly introduced. In order to make sure that the satellite-to-ground link is reliable, we calculate the link budget at 471 MHz for LEO small satellite. Additionally, the transmission power and reception sensitivity is 17 dBm and −123 dBm respectively. The result shows that the proposed subsystem is reliable in RF performance and can be used in other commercial satellite in the future.

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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, Guanghui 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 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 design and optimization processes of FuSTAR are described from three aspects: the neutronic and thermal-hydraulic system, the thermal transport system, and the power cycle system. 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 and the passive residual heat removal system and proved to be fast and efficient. Then the optimal parameters and configuration of the thermoelectric conversion system are obtained directly by using the superstructure optimization method, which saves computing resources greatly. Based on the above design and parameters, the inherent safety of FuSTAR is demonstrated through deterministic safety analysis. In addition, the iodine-sulfur cycle technology is also designed and analyzed, and the characteristics of tritium production in FuSTAR are calculated. The research provides important guidance for the detailed design and operation of FuSTAR. Moreover, this study highlights the significant potential of integrating nuclear energy with other energy sources in an optimized energy-production system. Based on the current research findings, prospects for future research directions are also suggested. © 2023, The Authors. All rights r

关键词： High temperature reactors

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An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

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Chinese Journal of Mechanical Engineering 2020年第2期33卷 43-55页

作者： Jimin Xu Changhuan Li Xusheng Miao Cuiping Zhang Xiaoyang Yuan Institute of Tribology School of Mechanical EngineeringHefei University of TechnologyHefei 230009China Aerospace Propulsion Institute China Aerospace Science and Technology CorporationXi’an 710100China Science Technology on Combustion Internal Flow and Thermal‑structure LaboratoryNorthwestern Polytechnical UniversityXi’an 710012China Superconducting Materials Research Center Laboratory Northwest Institute for Non-ferrous Metal ResearchXi’an 710016China Key Laboratory of Education Ministry for Modern Design and Rotor‑Bearing System Xi’an Jiaotong UniversityXi’an 710049China

There is a consensus in the aerospace field that the development of reusable liquid rockets can effectively reduce the launch *** pursuit of a long service life and reutilization highly depends on the bearing ***,the rolling element bearings(REBs)used in the existing rocket turbopumps present obvious and increasing limitations due to their mechanical contacting *** REBs,high rotational speed and long service life are two performance indexes that mutually restrict each *** go beyond the DN value(the product of the bearing bore and rotational speed)limit of REBs,the major space powers have conducted substantial explorations on the use of new types of bearings to replace the *** review discusses,first,the crucial role of bearings in rocket turbopumps and the related structural improvements of ***,with the prospect of application to the next generation of reusable liquid rocket turbopumps,the bearing candidates investigated by major space powers are summarized *** promising alternatives to REBs include fluid-film,foil,and magnetic bearings,together with the novel superconducting compound bearings recently proposed by our *** more than ten years of relevant research on fluid-film and magnetic bearings are also *** review is meaningful for the development of long-life and highly reliable bearings to be used in future reusable rocket turbopumps.

关键词： Aerospace Reusable liquid rocket turbopumps Rolling element bearings Bearing candidates Review

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The relationship between orthopedic clinical imaging and bone strength prediction

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Medicine in Novel technology and Devices 2021年第1期9卷 9-17页

作者： He Gong Meng Zhang Shaowei Jia Linwei Lv Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijingChina Department of Engineering Mechanics Nanling CampusJilin UniversityChangchun130025China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin300384China

Pathologic fracture is caused by bone diseases,which is common in middle-aged and elderly *** bone strength is the leading contributor to this type of ***,accurately quantifying bone strength could help clinicians assess individualized fracture risk and develop therapeutic *** clinical imaging including dual X-ray absorptiometry(DXA),computed tomography(CT),and magnetic resonance imaging(MRI)has been an important tool to obtain radiology images of bone,which could be further used for noninvasive assessment of bone strength and related fracture *** the development of biomechanics and computer technology,the combination of finite element analysis with orthopedic imaging is the most advanced method for noninvasive prediction of bone strength in *** this review,an overview is provided for the commonly noninvasive methods based on the radiology images(i.e.,DXA,CT,and MRI)to predict bone strength,which may improve the understanding of the relationship between orthopedic clinical imaging and biomechanics.

关键词： Orthopedic clinical imaging Biomechanics Bone strength Finite element analysis

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Numerical Simulation of Flow-Thermal Coupling Field Inside Upper Plenum and Hot Legs of Pressurized Water reactor (Pwr)

SSRN

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SSRN 2022年

作者： Sun, Ziyun Zhou, Xinzhi He, Zhengxi Xu, Tao Zhu, Jialiang Dong, Chenlong College of Electronics And Information Engineering Sichuan University No. 24 South Section 1 1st Ring Road Sichuan Chengdu China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China No. 328 Section 1 Changshun Avenue Sichuan Chengdu China

The temperature and flow rate of coolant in the hot legs of pressurized water reactor (PWR) systems directly reflect the nuclear power and the heat transfer state of the reactor core, and are key parameters for reactor power control and safety protection. Most of existing studies have been conducted to analyze the steady-state thermal hydraulic features in the upper plenum and hot legs from a spatial scale, but less from a temporal scale to describe and analyze the transient features. In order to meet the requirements of key parameters measurement and safe operation, this paper established a reasonably simplified 3D geometrical model of the upper plenum and hot legs of the HPR1000 reactor based on a multi-physics field simulation platform and investigated the steady-state and transient features of the flow-thermal coupling field of coolant under numerical simulation, focusing on the coupling analysis of the flow-thermal coupling field on the spatial and temporal scales. The analysis of the steady-state features shows that the coolant flowing into the upper plenum from the upper core plate is characterized by a high middle temperature and a low peripheral temperature. As a result, there is an uneven coolant temperature distribution at the inlet of the hot legs that the temperature differences between the cold lower part and hot upper part are relatively large. However, with the axial flow of coolant, the temperature distribution in hot legs tends to be more uniform and the temperature differences decrease. The simulation results show that the flow of the low temperature coolant in hot legs dominates the change of coolant temperature distribution. The analysis of the transient features shows that a small fluctuation of flow rate at the core outlet causes changes in the turbulent kinetic energy of coolant in hot legs, but the effect on coolant temperature distribution is relatively weak. These such variations on the temporal scale can change the coupling relations of c

关键词： Multiphysics

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