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Preliminary study on few group cross section representation method based on model tree algorithm

Preliminary study on few group cross section representation ...

2018 International Conference on Physics of reactors: reactor Physics Paving the Way Towards More Efficient systems, PHYSOR 2018

作者： Zhao, Wenbo Ju, Haitao Yu, Yingrui Chai, Xiaoming Yu, Junchong Peng, Xingjie Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

ISBN: (纸本)9781713808510

The tabular representation of few-group cross section is widely used for node wise two-step core simulations. However, it may take too much memory usage for pin-by-pin two-step simulations. A few-group cross section representation method for PWR has been developed to reduce memory usage in this paper. The few-group cross sections are represented as the sum of a base term and a collection of partial terms. Each of these terms is fitted by modified model tree. The case matrix of training data set is similar with that of the conventional methods such as the piece wise interpolation and the tabular representation. Two modifications have been made for the model tree algorithm: 1) burnup is the only variable to split data set, 2) linear regression method on nodes of the tree is replaced with polynomial fitting method according to priori knowledge of the relationship between cross sections and state variables. Through the modifications accuracy and generalization ability are achieved without the pruning procedure. Then the lattice calculations for test data set could be canceled. Tests on the typical PWR lattice are performed. Numerical results show that for the worst case the memory usage of this method is less than 30% of the tabular representation, when the maximum error of reactivity is less than 500 pcm. The memory usage for other cross sections is less than 10% with high accuracy. Optimization of the target tolerance criteria should be tested for fast group cross sections. Large errors in thermal group absorption and fission production cross sections lead to large errors in Kinf and it needs more study on regression model. The method combined with the tabular representation might be more suitable for the pin-by-pin two-step simulations. © 2018 International Conference on Physics of reactors, PHYSOR 2018: reactor Physics Paving the Way Towards More Efficient systems. All rights reserved.

关键词： Errors

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Maap5 simulation of pwr high-pressure core melting severe accident due to smallbreak loca

Maap5 simulation of pwr high-pressure core melting severe ac...

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2018 International Congress on Advances in Nuclear Power Plants, ICAPP 2018

作者： Wu, Xiaoli Li, Wei Deng, Jian Deng, Chunrui Hou, Liqiang Zhang, Dan Yuan, Hongsheng Science Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9780894487552

MAAP5 is capable of simulating the whole response of a PWR nuclear power plant under severe accident conditions. An analysis of the severe accident scenarios in a PWR by MAAP5 were carried out. It was assumed that the severe accident was initiated by an unusual smallbreak loss-of-coolant accident (SBLOCA) at the reactor pressure vessel (RPV) lower head and the failure of highpressure injection system (HPIS) in a PWR by using MAAP5 were carried out. Different break sizes with and without manual depressurization of the reactor coolant system (RCS) were studied. The results showed that without manually depressurization the RCS, reactor core underwent slow heatup and completely melted and eventually failed the RPV lower head at the primary system pressure of 6.87 MPa for 0.4-inch-break LOCA and 2.71 MPa for 1.0-inch-break LOCA. On the other hand, timely manually opening the pressurizer (PZR) safety valves (SVs) was an effective mitigation measure to recover the core coolabilty by cold-leg accumulator injection system (AIS) and low-pressure injection system (LPIS). Besides, reasonably manually opening the steam generators (SGs) SVs while keeping the auxiliary feedwater work also helped to depressurize the RCS and prevent the severe accident. Both of the two mitigation measures successfully prevented the core from complete melt, but the latter one is preferable to the former one provided no steam generator tube rupture took place. © 2018 American Nuclear Society. All rights reserved.

关键词： Loss of coolant accidents

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Multiple branches coupling property and design of PRHRs

Multiple branches coupling property and design of PRHRs

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AISTech 2018 Iron and Steel technology Conference and Exposition

作者： Zhuohua, Zhang Xu, Ran Feng, Li Lin, Xian Ke, Zhou Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9781935117728

Nuclear reactor applied on ship or floating platform recommend miniaturization and optimization of PRHRs. Due to much larger volume and heat transfer area in PRHRs heat exchanger, miniaturization and design of PRHRs need consider many constraints such as volume and systems configuration in containment. In normal reactor design such constraints are not so rigorous, but in reactor design for floating platform it takes significant difficulties. A multiple branches coupling system is constructed in the paper which describes the actual relationship between PRHRs and other systems or equipment, and by combining temperature distribution in heat exchanger and conservation equations of coupling system, the design parameters set satisfied design requirement can be calculated and optimization of design can be completed by programming solving method. © 2018 by AIST.

关键词： Heat transfer

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Multi-Scale Fusion Algorithm for AUVs Integrated Navigation systems

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Journal of Beijing Institute of technology 2019年第4期28卷 725-730页

作者： Yushan Sun Fanyu Wu Yuqi Wang Guocheng Zhang Bin Kong Science and Technology on Underwater Vehicle Laboratory Harbin Engineering UniversityHarbin 150001China Key Laboratory of System Control and Information Processing Shanghai Jiao Tong UniversityShanghai 200030China Wuhan Second Ship Design and Research Institute Wuhan 430205China

To deal with the low location accuracy issue of existing underwater navigation technologies in autonomous underwater vehicles(AUVs),a distributed fusion algorithm which combines the model's analysis method with a multi-scale transformation method is proposed for integrated navigation system based on ***,integrated navigation system theory and system error sources are introduced in ***,a navigation system's observation equation on the original scale is decomposed into different scales by the discrete wavelet transform method,and noise reduction is performed by setting the wavelet de-noising *** last,the dynamic equation and observation equations are fused on different scales by the wavelet transformation and Kalman *** results show that the proposed algorithm has smaller navigation error and higher navigation accuracy.

关键词： autonomous underwater vehicles(AUVs) integrated navigation system wavelet transform multi-scale transform Kalman filter

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Research on the response of core barrel under random turbulence excitation 25

Research on the response of core barrel under random turbule...

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25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018

作者： Huang, Xuan Wu, Wan-Jun Qi, Huan-Huan Feng, Zhi-Peng Liu, Shuai Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

ISBN: (纸本)9781510868458

The flow-induced vibration of reactor structures is directly related to nuclear safety and has long been closely watched by the nuclear engineering community. A large number of theoretical, experimental and numerical analysis research work are carried out at home and abroad. In one hand, the test means cost a lot of money and time;on the other hand due to the restriction of test conditions, we only can get the measurement results about part of the structure under specific conditions. Therefore, from the design point of view, the theoretical or numerical analysis methods should be developed to predict structural flow induced vibration response in order to compensate for the lack of test methods. For the purpose of completing the flow-induced vibration analysis of the components in the reactor, it is necessary to analyse the vibration characteristics of the components in the reactor. According to the fluid excitation situation, this paper based on the test study two kinds of core barrel calculation method of forced vibration response under turbulent excitation. The advantages and disadvantages of these two methods are described from the aspects of calculation model, calculation input, analysis method and calculation result. © 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. All rights reserved.

关键词： Vibration analysis

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The implicit runge kutta method for solving point burnup equations

The implicit runge kutta method for solving point burnup equ...

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2018 Transactions of the American Nuclear Society, ANS 2018

作者： Cai, Yun Peng, Xingjie Li, Qing Qin, Dong Jiang, Zhumin Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

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I3−/I−Redox Reaction-mediated Organic Zinc-Air Batteries with Accelerated Kinetics and Long Shelf Lives

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Angewandte Chemie 2023年第26期135卷

作者： Mangwei Cui Ninggui Ma Hao Lei Youfa Liu Wei Ling Sheng Chen Jiaqi Wang Prof. Hongfei Li Zhaohui Li Prof. Jun Fan Prof. Yan Huang State Key Laboratory of Advanced Welding and Joining Sauvage Laboratory for Smart Materials Shenzhen Key Laboratory of Flexible Printed Electronics Technology School of Materials Science and Engineering Harbin Institute of Technology (Shenzhen) Shenzhen 518055 China Department of Materials Science and Engineering City University of Hong Kong 83 Tat Chee Avenue Kowloon Hong Kong 999077 China Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu 610064 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen 518055 China Songshan Lake Materials Laboratory Dongguan 523808 China Shenzhen China Star Optoelectronic Semiconductor Display Technology Co. Ltd. Shenzhen 518055 China

The storage time of Zn-air batteries (ZABs) for practical implementation have been neglected long-lastingly. ZABs based on organic solvents promise long shelf lives but suffer from sluggish kinetics. Here, we report a longly storable ZAB with accelerated kinetics mediated by I 3 − /I − redox. In the charge process, the electrooxidation of Zn 5 (OH) 8 Cl 2 ⋅H 2 O is accelerated by I 3 − chemical oxidation. In the discharge process, I − adsorbed on the electrocatalyst changes the energy level of oxygen reduction reaction (ORR). Benefitting from these advantages, the prepared ZAB shows remarkably improved round-trip efficiency (56.03 % vs. 30.97 % without the mediator), and long-term cycling time (>2600 h) in ambient air without replacing any components or applying any protective treatment to Zn anode and electrocatalyst. After resting for 30 days without any protection, it can still directly discharge continuously for 32.5 h and charge/discharge very stably for 2200 h (440 cycles), which is evidently superior to aqueous ZABs (only 0/0.25 h, and 50/25 h (10/5 cycles) by mild/alkaline electrolyte replenishment). This study provides a strategy to solve both storage and sluggish kinetics issues that have been plaguing ZABs for centuries, opening up a new avenue to the industrial application of ZABs.

关键词： Iodine-Containing Reaction Kinetics Redox Mediators Storage Time Zn-Air Batteries

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A Service-Environment-Oriented Shape Reconstruction Method of Vehicle-borne Active Phased Array Antenna

A Service-Environment-Oriented Shape Reconstruction Method o...

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IEEE International Conference on Radar

作者： Pengying Xu Xiaoxian Xu Yan Wang Yucheng Teng Congsi Wang Dongming Ge Mingkui Kang Shuai Yuan Xuezi Wang Key Laboratory of Electronic Equipment Structure Design Ministry of Education Xidian University Xi'an China School of Information and Control Engineering Xi'an University of Architecture and Technology Xi'an China Beijing Institute of Spacecraft System Engineering Beijing China No.771 Institute of China Aerospace Science and Technology Corporation Xi'an China China Electronics Technology Group Corporation No.38 Research Institute Hefei China

ISBN: (纸本)9781665468893

Modern electronic equipment has been moving towards large scale and increased complexity. Affected by such factors as complex working environments, the performance of a large number of structures in engineering is degraded or even destroyed. Therefore, structure shape estimation is of great significance. The complexity of the structure, however, makes it impossible for a single deformation evaluation algorithm to evaluate the structure comprehensively and accurately. In this paper, a modal-approximate curve (M-AC) method, using a small amount of strain data, is proposed for block shape estimation of structures. Three typical wind load experiments are carried out on the finite element model (FEM) of the vehicle-borne active phased array antenna, and the effectiveness of the algorithm is verified. Under the wind speed of 28 (m/s), the deformation of antenna front is 104.70 mm and the estimation accuracy of the M-AC method is 87.43%, which is 16.47% higher than that of the modal approach. The results indicate that the estimated displacement is consistent well with the simulation results of the finite element method.

关键词： Phased arrays Shape Estimation Radar Radar antennas Finite element analysis Loaded antennas

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An iterative method for the solution of equilibrium position in the shaft-hole assembly based on spring contact model

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Procedia CIRP 2021年 97卷 230-234页

作者： Yuanyang Zhang Junkang Guo Xianming Gao Jun Hong School of Mechanical Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 P R China Key Laboratory for Modern Design & Rotor-Bearing System Ministry of Education Xi'an Jiaotong University Xi'an Shaanxi 710049 P R China College of Mechanical and Electrical Engineering Shaanxi University of Science and Technology Xi'an 710021 China

The traditional finite element method has the advantages of strong versatility and high calculation accuracy. Thus it is widely applied in various numerical simulation problems. Although the traditional finite element method for solving the shaft-hole assembly problem can obtain better solution accuracy, the process of modeling and calculation take a long time and thus cannot meet the engineering application requirements when the equilibrium position after the assembly needs to be obtained quickly to guide the subsequent process. In this paper, an iterative method based on the spring contact model is proposed. Firstly, the actual form error of the shaft and hole is characterized by the Fourier series expansion method; Then, in the contact surface, we established a discrete spring contact model and obtained the equivalent stiffness of the coupling spring through the discrete solid model. The balance iterative calculation based on the form errors and contact deformation force can finally determine the equilibrium position after the assembly. Compared with the calculation results of the finite element model, the equilibrium position of the shaft-hole assembly can be quickly solved under the condition of sacrificing certain precision. From this aspect it can be estimated that this method has a good potential for engineering application.

关键词： Assembly design Form error Spring contact model Finite element method

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Lightweight Task-Oriented Semantic Communication Empowered by Large-Scale AI Models

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IEEE Transactions on Vehicular technology 2025年

作者： Liu, Chuanhong Guo, Caili Yang, Yang Chen, Mingzhe Quek, Tony Q. S. Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing100876 China Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks School of Information and Communication Engineering Beijing100876 China University of Miami Department of Electrical and Computer Engineering Institute for Data Science and Computing Coral GablesFL United States Singapore University of Technology and Design Dept. of Information Systems Technology and Design 487372 Singapore

Recent studies have focused on leveraging large-scale artificial intelligence (LAI) models to improve semantic representation and compression capabilities. However, the substantial computational demands of LAI models pose significant challenges for real-time communication scenarios. To address this, this paper proposes utilizing knowledge distillation (KD) techniques to extract and condense knowledge from LAI models, effectively reducing model complexity and computation latency. Nevertheless, the inherent complexity of LAI models leads to prolonged inference times during distillation, while their lack of channel awareness compromises the distillation performance. These limitations make standard KD methods unsuitable for task-oriented semantic communication scenarios. To address these issues, we propose a fast distillation method featuring a pre-stored compression mechanism that eliminates the need for repetitive inference, significantly improving efficiency. Furthermore, a channel adaptive module is incorporated to dynamically adjust the transmitted semantic information based on varying channel conditions, enhancing communication reliability and adaptability. In addition, an information bottleneck-based loss function is derived to guide the fast distillation process. Simulation results verify that the proposed scheme outperform baselines in term of task accuracy, model size, computation latency, and training data requirements. © 1967-2012 IEEE.

关键词： NP-hard

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