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2021 4th International Conference on Mechatronics and Computer technology Engineering, MCTE 2021

作者： Li, Jing Liu, Yanyang Qing, Xianguo Xiao, Kai Zhang, Ying Yang, Pengcheng Yang, Yue Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Department of Engineering The University of Sydney Sydney2006 Australia

The nuclear reactor control system plays a crucial role in the operation of nuclear power plants. The coordinated control of power control and steam generator level control has become one of the most important control problems in these systems. In this paper, we propose a mathematical model of the coordinated control system, and then transform it into a reinforcement learning model and develop a deep reinforcement learning control algorithm so-called DDPG algorithm to solve the problem. Through simulation experiments, our proposed algorithm has shown an extremely remarkable control performance. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Steam generators

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Pressure-assisted Silver Sintering Structure Optimization for Power Modules 5

Pressure-assisted Silver Sintering Structure Optimization fo...

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5th International Conference on Optoelectronic science and Materials, ICOSM 2023

作者： Zhang, Hao Xing, Yulong Gao, Lilan Liu, Zheng Tan, Yansong Lu, Guoquan Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin300384 China National Demonstration Center or Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China Tianjin Yixunyuan New Material Technology Co. Ltd. Tianjin300380 China School of Chemical Engineering Tianjin University Tianjin300350 China School of Materials Science and Engineering Virginia Polytechnic Institute and State University BlacksburgVA24061 United States

ISBN: (纸本)9781510674547

As mobile technology evolves from 5G to 6G, the demand for third-generation semiconductors such as SiC with higher power and frequency capabilities is increasing. Silicon Carbide power modules generate significant heat during operation, requiring large-area nano-silver sintering technology to improve module performance and reliability. However, in large-area sintering processes, low exhaust efficiency of solder paste by-products and uneven sintering pressure of the nano-silver paste result in poor sintering quality of the silver layer. This study aims to improve the sintering quality of interconnected silver layers by optimizing the sintering pressure distribution and adding rubber spacers to the sintering structure. ABAQUS was used to quantitatively analyze the effects of pressure methods and gasket material, diameter, and thickness on the stress distribution in the silver layer. Finally, based on the simulation results, an optimized sintering structure was proposed to unify the pressure and reduce the stress concentration in the silver layer, and verified experimentally by sintering tests. Compared with the traditional sintering structure, the application of a 2 mm thick fluoro rubber gasket with the same surface area as the silver layer in the optimized structure reduced the porosity to 2.15% and achieved a more dense sintered silver layer. © 2024 SPIE.

关键词： Finite element method

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Exploring the effects of work zone on vehicular flow on ring freeways with a tunnel using a three-lane continuum model

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International Journal of Transportation science and technology 2024年第2期14卷 27-41页

作者： Shan Li M.N.Smirnova Shanjun Yang N.N.Smirnov Zuojin Zhu CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230022China Faculty of Mechanics and Mathematics Lomonosov Moscow State UniversityMoscow 119992Russia Scientific Research Institute for System Analysis Russian Academy of SciencesMoscow 117218Russia Moscow Center for Fundamental and Applied Mathematics Moscow 119991Russia Physical Education Center USTCHefei 230026China

Freeway work zone forms as a result of traffic crash or road *** ascertain the effects of work zone with lane II completely blocked on vehicular flow on ring freeways with a tunnel,a three-lane continuum model is put *** mandatory net lanechanging rate from lane II to lane I or III just upstream of the work zone is described by a random number model,with the random number being produced within a small range around a median based on a golden section *** net-changing rate between adjacent lanes is described using a lane-changing time on the basis of an assumption:the time ratio to relaxation time equals infinity when the absolute value of traffic densities between the two adjacent lanes is less than 1 veh/km,implying that the net-changing rate is zero;otherwise,the time ratio is inversely proportional to the vehicular spatial headway,which is equal to unity for traffic flow at saturation state,but infinity when the traffic flow is completely *** is assumed that the freeway is a three lane ring with a total length of 100 km,and has a tunnel with a speed limit of 60 km/h and a length of 1.6 km located downstream the work zone with a length of 0.16 *** free flow speeds on lanes I,II,and III are 120 km/h,100 km/h,and 85 km/h,*** the vehicular flow on the ring freeway with a tunnel,numerical simulations based on the three-lane continuum model are carried out with a reliable numerical method of high *** is found that the vehicular flow has two thresholds of traffic jam formation,one depending upon the tunnel and the other upon the work *** tunnel triggers a traffic jam when the initial density normalized by jam density is equal to the first threshold 0.15,and the work zone originates another traffic jam when the normalized initial density equals the second threshold *** freeway tunnel plays a dominant role in the prediction of mean travel time as soon as the tunnel has generated a traffic jam at the tunn

关键词： Work zone Three-lane continuum model Vehicular lane changing time Vehicle fuel consumption Threshold of traffic jam formation

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Two-dimensional CuO nanosheets-induced MOF composites and derivatives for dendrite-free zinc-ion batteries

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纳米研究（英文版） 2023年第5期16卷 6881-6889页

作者： Guoqiang Yuan Yang-Yi Liu Jun Xia Yichun Su Wenxian Wei YinBo Zhu Yang An HengAn Wu Qiang Xu Huan Pang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China School of Electrical Engineering Engineering Technology Research Center of Optoelectronic Technology ApplianceTongling UniversityTangling 244061China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaHefei 230027China Department of Materials Science and Engineering SUSTech Academy for Advanced Interdisciplinary StudiesSouthern University of Science and TechnologyShenzhen 518055China

Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries(AZIBs).In this work,we designed to grow zeolitic imidazolate framework-8(ZIF-8)uniformly on CuO nanosheets(NSs)and prepared carbon-coated CuZn alloy NSs(CuZn@C NSs)by calcination under H2/Ar *** reflected by extended X-ray absorption fine structure(EXAFS),density functional theory(DFT),and in-situ Raman,the Cu-Zn and Zn-N bonds present in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and inhibit the formation of Zn *** the same time,CuZn@C NSs hinder the direct contact between zinc anode and electrolyte,preventing the occurrence of side *** impressively,the symmetric cells constructed with CuZn@C NSs anodes exhibited excellent zinc plating/exfoliation performance and long life cycle at different current densities with low voltage *** addition,low polarization,high capacity retention,and long cycle life over 1000 cycles at 5 A·g-1 were achieved when CuZn@C NSs were used as anodes for CuZn@C/V2O5 full cells.

关键词： two-dimensional CuO nanosheet metal-organic frameworks (MOFs)-based composites carbon-coated CuZn alloy nanosheets dendrite-free zinc-ion battery

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Analysis of the impact of long-term service of inverter devices on electromagnetic compatibility

Analysis of the impact of long-term service of inverter devi...

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China Power Supply Society Electromagnetic Compatibility Conference (CPEMC)

作者： Ruiheng Zhang Xuejun Pei Jin Meng Hongming Fan Peng Zhou Yuzhang Yuan Power Electronics and Energy Management Key Laboratory Ministry of Education of China Huazhong University of Science and Technology Wuhan China National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan China

ISBN: (数字)9798331509552

ISBN: (纸本)9798331509569

Taking the IGBT power module of the inverter device as the research object, finite element analysis technology was used to explore the influence of long-term service on the thermal characteristics and stress-strain of the IGBT module. At the same time, the influence of service aging on the electromagnetic compatibility performance of the device was studied, and the finite element simulation results were verified through accelerated aging experiments. The results showed that during the long-term operation of the IGBT module, due to the different thermal expansion coefficients of its materials, strain differences were found, ultimately leading to an increase in its ground capacitance, resulting in an increase in the amplitude of the common mode conducted noise of the device by 3dBμA in the frequency band after 20MHz. This study will provide theoretical guidance for the electromagnetic compatibility design of inverter devices for long-term service.

关键词： Insulated gate bipolar transistors Performance evaluation Accelerated aging Electromagnetic compatibility Fatigue Inverters Thermal noise Finite element analysis Thermal stresses Strain

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High sensitivity distributed lateral pressure sensor based on BOTDR 3

High sensitivity distributed lateral pressure sensor based o...

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3rd International Computing Imaging Conference, CITA 2023

作者： Wang, Ying Zhu, Zongda Xia, Xiaomeng Chen, Tong Deng, Yue Li, Can Bai, Fuwen Jin, Wei Tang, Xiaohui State Grid Information & Telecommunication Branch Beijing100761 China National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology Harbin150001 China Energy Planning Institute Southwest Electric Power Design Institute co. Ltd Chengdu610021 China

ISBN: (纸本)9781510671409

In this work, a high-sensitivity distributed lateral pressure sensor based on Brillouin optical time-domain reflectometry (BOTDR) technique is proposed to enhance the pressure sensitivity using a double-coated single-mode fiber (SMF). Firstly, a pressure-induced strain model is developed to analyze the enhancement mechanism of pressure sensitivity by Brillouin frequency shift (BFS). With increasing of outer coating radius, or with decreasing of the Young’s modulus and Poisson’s ratio of outer coating, the lateral pressure sensitivity increases. By using a double-coated SMF whose outer coating radius is 1500 µm, a high sensitivity of -3.51 MHz/MPa in the range of 0-30 MPa is achieved, which is about five times higher than that of single-coated SMF. At a spatial resolution of 1.5 m, the maximum measurement error of the proposed pressure sensing system is less than 0.09 MPa. © 2023 SPIE.

关键词： Single mode fibers

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Experimental Investigation and Mathematical Modeling on the Roles of Suspension and Deposition for Pool Boiling of Nanofluids

SSRN

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SSRN 2023年

作者： Peng, Cheng Song, Youya Wu, Jiang Deng, Jian College of Energy and Mechanical Engineering Shanghai University of Electric Power Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

The influence of deposited and suspended nanoparticles on pool boiling of Al2O3 nanofluids was examined through visualization approach in this paper. The deposited nanoparticles cause the wettability to progressively increase as the concentration of nanofluid increases. The findings in this study demonstrate that deposited and suspended nanoparticles increase the frequency of bubble detachment and the quantity of active nucleate sites in water at a mass concentration ranging from 0.001% to 0.005%. The bubble behavior prediction equation was then rectified based on the surface contact angle, and the error margin was found to be within ±12% by comparing the experimental data. Based on which, the predicted values of the bubble behavior parameters were substituted into a corrected equation for boiling heat transfer. By validating the experimental data, the error margin was found to be within ±25%. Additionally, it was discovered that the effect of deposited nanoparticles on boiling heat transfer is always dominant at the heat fluxes between 50 and 250 kW/m2. © 2023, The Authors. All rights reserved.

关键词： Nanoparticles

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Thermal-Hydraulic Characteristics of Helical Cruciform Single Rod Based on Cfd Investigation

SSRN

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SSRN 2024年

作者： Chen, Yiwen Zhang, Dalin Jiang, Dianqiang Deng, Jian Zhang, Xisi Wang, Xinan Tian, Wenxi Qiu, Suizheng Su, Guanghui 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 Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China China Institute of Atomic Energy Beijing611731 China

To increase power density in nuclear reactors, the helical cruciform fuel (HCF) is designed as a fundamental element. HCF takes advantages of strong mixing effects, self-supporting features, and strengthened heat transfer, potential to increase the fuel performance in nuclear reactors. In this paper, friction factor and heat transfer coefficient empirical correlations of HCF single rod cooled by water were proposed using a geometric dimensionless number based on numerical simulation. The velocity field, and temperature distribution were obtained to discuss influences of geometric sizes on the fuel performance. Finally, correlations with a geometric dimensionless number were validated with various cases, whose application conditions were also proposed and discussed. This paper provides a guide for study of heat transfer and fluid flow in helical structures, and a reference for establishment of reactor system model using helical cruciform fuels. © 2024, The Authors. All rights reserved.

关键词： Heat transfer coefficients

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Q-Learning for Finite-Horizon H8Tracking Control of Unknown Linear Discrete-Time systems 42

Q-Learning for Finite-Horizon H8Tracking Control of Unknown ...

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42nd Chinese Control Conference, CCC 2023

作者： Liu, Mingxiang Cai, Qianqian Meng, Wei Li, Dandan Fu, Minyue Han, Zhimin School of Automation Guangdong University of Technology Guangzhou510006 China Guangdong Province Key Laboratory of Intelligent Decision and Cooperative Control Guangzhou510006 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China School of Automation Hangzhou Dianzi University Hangzhou310018 China

ISBN: (纸本)9789887581543

In this paper, we present a Q-learning algorithm for finite-horizon H8 tracking control of unknown linear discrete-time systems. Finite horizon control is challenging due to its correspondence with a time-varying Riccati equation. The proposed algorithm can determine the solution of the time-varying Riccati equation with unknown system dynamics. We first establish the time-varying Q-function, then propose a corresponding Q-learning algorithm and prove its convergence. Finally, the proposed algorithm is proved to be effective through numerical examples. © 2023 Technical Committee on Control Theory, Chinese Association of Automation.

关键词： Riccati equations

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Ballistic performance of CFRP under normal and oblique impacts by square fragments: Experimental, numerical, and theoretical investigations

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Thin-Walled Structures 2025年 215卷

作者： Feng, Bo Dong, Yongxiang Min, Qiang Liu, Jian Shi, Xinping Tian, Yumo An, Fengjiang State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of Technology Beijing 100081 China National Key Laboratory of Digital and Agile Aircraft Design Chengdu Aircraft Design & Research Institute Chengdu610091 China Beijing Institute of Electronic System Engineering Beijing 1000854 China

High-performance carbon fibre-reinforced polymer (CFRP) composites are commonly used as external protective structures in military and aerospace applications and are frequently subjected to impact from fragments or projectiles. This study investigated the damage mechanisms of CFRP laminates under normal and oblique impacts from square fragments. Impact tests were conducted on 3–9 mm CFRP laminates using 4 g and 7 g square fragments at velocities ranging from 100 to 1300 m/s and impact angles from 0° to 60° Finite element simulations based on yarn-scale models were also performed. The results revealed that under oblique penetration conditions, the fragment edge initially contacting the target plate caused deeper shear damage. An analytical model was developed to predict the residual velocity of the fragments and the ballistic limit velocity (BLV) of the CFRP laminates. The average error between the model predictions and experimental results was 8.42 %, whereas that between the predictions and simulation results was 3.69 %. Interestingly, the analysis revealed a non-zero minimum resistance angle for the laminate under square fragment impact, at which the BLV of the target plate was minimised. The predicted distribution range of the minimum resistance angle in this study was 23–28° The developed predictive model and identified "minimum resistance angle" provide theoretical foundations for protective engineering design, bridging laboratory research to real-world high-risk applications such as military and aerospace. © 2025 Elsevier Ltd

关键词： Military applications

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