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Effect of ECAP process on liquid distribution of AZ80M alloy during semi-solid isothermal heat treatment

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Transactions of Nonferrous Metals Society of China 2021年第6期31卷 1599-1611页

作者： Ling-ling FAN Ming-yang ZHOU Yang-yang GUO Yu-wen-xi ZHANG Gao-feng QUAN Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

Two kinds of semi-solid samples of AZ80−0.2Y−0.15Ca(wt.%)(AZ80M)magnesium alloy were prepared by semi-solid isothermal heat treatment of materials with and without equal channel angular pressing(ECAP)*** microstructures of initial and semi-solid treated samples were compared and *** results showed a significant difference in the liquid phase distribution between three-pass ECAP processed(3P)and as-received samples during the isothermal heating *** semi-solid 3P sample showed a more uniform liquid distribution due to its smaller dihedral ***,the coarsening processes of solid grains of as-received and 3P samples were dominated by the coalescence and Ostwald ripening mechanism,*** difference of coarsening processes was mainly related to the proportion of the high-angle grain boundaries in materials,which further affected the evolution behavior of the liquid pools.

关键词： AZ80M equal channel angular pressing semi-solid microstructure liquid phase distribution coarsening mechanism

Improved Lbe Corrosion Resistance and Mechanical Properties of Reactive Gas Pulse Sputtered Alcrfemoti/(Alcrfemoti)N Composite Multilayered High-Entropy Alloy Coatings

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SSRN 2022年

作者： Yang, Jian Lv, Liangliang Zhou, Mingyang Chen, Qingsong Liu, Hao Zhong, Yilong Deng, Jiuguo Zhang, Wei Zhu, Changda Liu, Ning Yang, Jijun Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu610064 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The (HEA/HEAN)-n multilayer coatings consisting of alternating (AlCrFeMoTi)N (top) and AlCrFeMoTi layers were specially designed and successfully deposited on F/M steel substrate by reactive magnetron sputtering technology. The dependence of microstructure, mechanical properties and LBE corrosion resistance on interlayer interface density was systematically investigated. The multilayer structure design improved the mechanical properties and high-temperature structural stability of the multilayer coatings. Furthermore, the LBE corrosion experiments displayed that the (HEA/HEAN)-12 multilayer coating with optimum interlayer interface density exhibited the most excellent LBE corrosion resistance. The oxidation corrosion mechanism of the (HEA/HEAN)-n multilayer coatings were also discussed intensively. © 2022, The Authors. All rights reserved.

关键词： Corrosion resistance

The Instability Marsh Phenomenon and Marginal Stability Boundary Distortion of Density Wave Oscillation in Parallel Channels

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SSRN 2024年

作者： Sun, Ducheng Ma, Zaiyong Lu, Q. Liu, C.W. Pan, L.M. School of Energy and Power Engineering Shandong University No. 17923 Jingshi Road Jinan250061 China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Ministry of Education Chongqing400044 China Department of Nuclear Engineering and Technology Chongqing University Chongqing400044 China Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China

Density wave oscillation (DWO) in parallel channels is an important problem that has been widely studied. The marginal stability boundary (MSB) is often found to be "L " shaped on the N pch -N sub plane, but some very different shapes were also reported. In this paper, the instability marsh region which could occur in the traditional instable region but having both instability and stability sections was presented and discussed, which is found to be an explanation of the distortion of MSB. The analysis of the instability marsh region showed that the evolution of instability marsh should be due to the stability change when operation condition changes, which can be estimated with the analysis of the two-phase and single phase pressure drop variation, as well as Ma’s stability criterion for different heat flux profiles. Variation of instability marsh with different heat flux profile, inlet and outlet resistance coefficient, mass flow and pressure were obtained and analyzed, and the effects of these parameters on instability marsh variation were found to be well interpreted with stability change. The calculation and analysis of instability marsh showed a clear evolution figure of the distortion of MSB under different conditions, and related research could be helpful in better understanding the flow instability in parallel channels. © 2024, The Authors. All rights reserved.

关键词： Stability criteria

Experimental Study of Coherent Structures Downstream Mixing Vaned Spacer Grid of Different Inclination Angles in a 5×5 Rod Bundle by Tr-Piv

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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

Influence of Si Addition on the Microstructure, Mechanical and Lbe Corrosion Properties of an Amorphous Alcrfemoti High-Entropy Alloy Coating

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SSRN 2022年

关键词： Corrosive effects

Experimental Study of Coherent Structures Downstream Mixing Vaned Spacer Grid of Different Inclination Angles in a 5×5 Rod Bundle by Tr-Piv

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SSRN 2022年

关键词： Reynolds number

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

Research on Data Optimization technology of Multi-Source Sensing Signal in Nuclear Power Plants

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SSRN 2023年

作者： Liu, Yongchao Li, Tong Xiao, Kai Chen, Jie Tan, Xin Cheng, Jiahao Tan, Sichao Wang, Bo He, Zhengxi Shen, Jihong Gao, Puzhen Tian, Ruifeng College of Nuclear Science and Technology Harbin Engineering University Harbin150001 China Heilongjiang Provincial Key Laboratory of Nuclear Power System & Equipment Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Insitute of China Chengdu610213 China College of Mathematical Sciences Harbin Engineering University Harbin150001 China

The sensor signals collected by the nuclear power plant system equipment are mixed with complex noise information. The uncertainty of sensing data directly affects the application effect of artificial intelligence on nuclear power data mining. Traditional denoising methods have poor adaptability to different noisy data, are highly dependent on researchers, and take a long time. This paper proposes a data optimization technology based on a hybrid adaptive real-time denoising model, which can realize data distribution self-adaptation and algorithm super-parameter self-optimization according to the characteristics of noisy source data. Partition denoising processing of source data. The application of examples and simulation experiments show that this technology can effectively realize the optimization of nuclear power operation data, and provide important technical support for the engineering application of artificial intelligence technology in the complex noise environment of nuclear power plants. © 2023, The Authors. All rights reserved.

关键词： Nuclear energy

Significant Wave Height Prediction Based on VMD-SA-MLP-BP

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Significant Wave Height Prediction Based on VMD-SA-MLP-BP

2023 China Automation Congress, CAC 2023

作者： Wu, Yining Zhang, Runfeng Liu, Fang Liu, Zhenzhong Wu, Jianguo Dong, Haonan School of Mechanical Engineering Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin300384 China Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education China Yichang Research Institute of Testing Technology Yichang443003 China Tianjin Hanhailanfan Marine Technology Co. Ltd. Tianjin300457 China School of Computer Science and Engineering Tianjin University of Technology Tianjin300384 China

ISBN: (纸本)9798350303759

Waves seriously impact port construction, worldwide route planning, military activities, and wave power generation. To improve the accuracy of significant wave height prediction, we proposed a novel prediction method, a multi-layer perceptron combined with a backpropagation adjustment (MLP-BP) prediction model that combines mutation mode decomposition (VMD) and a simulated annealing optimization algorithm (SA). Firstly, we use the variable modulus method to decompose the significant wave height sequence data and transform the wave height sequence into multiple different sub-modes (IMF) to reduce the complexity and non-stationarity of the data. Secondly, the simulated annealing algorithm (SA) is used to optimize the weight and bias of the MLP-BP neural network to find the optimal parameter configuration and improve the performance and generalization ability of the prediction model. Finally, the decomposed sub-modal components of each significant wave height sequence are inserted into the MLP-BP neural network and the predicted values of each element are summed to obtain the final significant wave height prediction. The prediction results of the SSA-MLP-BP, PSO-MLP-BP, SA-MLP-BP, and VMD-SA-MLP-BP were compared and demonstrated that the VMD-SA-MLP-BP model performed best. The MAE, MAPE, MSE, RMSE, and R2 of the prediction evaluation indexes were 0.036 m, 11.7%, 0.004 m2, 0.067 m, and 0.983, respectively, which performed well in predicting significant wave height. © 2023 IEEE.

关键词： Variational mode decomposition