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SSRN 2023年

作者： Chen, Wuguang Huang, Guangyuan Hu, Yuanbiao Junlian, Yin Wang, Dezhong Li, Songwei Yang, Fan School of Nuclear Science and Engineering Shanghai Jiaotong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

Narrow rectangular channels are widely used in high heat flux applications, due to the high heat transfer efficiency and compact structure. However, a rare understanding was known about the two-phase turbulent characteristics. In this study, an experimental investigation of bubble and turbulent characteristics of dispersed bubbly flow in the narrow rectangular channel was carried out by using the high-speed camera and two-phase particle image velocimetry. The bubble size effect was studied independently using the continuous spectrum bubble generator. According to the results, the bubble size distribution conforms to a Weibull distribution, and the wall-peak void fraction distributions were found. Both turbulent enhancement and suppression were observed in current conditions. Large bubbles enhance turbulence intensity, while small bubbles suppress it. The eddy viscosity ratio [[EQUATION]] characterizes the modification of turbulence intensity by bubbles, with a critical value of [[EQUATION]]. © 2023, The Authors. All rights reserved.

关键词： High speed cameras

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Intra Fast Mode Decision Algorithm and Hardware design for AVS2

Intra Fast Mode Decision Algorithm and Hardware Design for A...

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2021 International Conference on Signal Processing and Machine Learning, CONF-SPML 2021

作者： Xie, Hao Liu, Kaiyang Zhao, Yang Zheng, Xiao Qing, Xianguo Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu China Peking University School of Software and Microelectronics Beijing China

ISBN: (纸本)9781665417341

AVS2 is a kind of video coding standard proposed by China, it adopts 33 intra prediction modes to improve coding performance, while the computational complexity has increased dramatically. In order to reduce the complexity of AVS2 intra mode decision and make the AVS2 hardware encoder meet real-time requirements, this paper proposes the AVS2 intra fast mode decision algorithm and hardware design. The experimental results show that the intra mode decision algorithm and hardware design proposed in this paper can meet the throughput requirement of 1920x1080@60fps at a clock frequency of 300MHz. By using Xilinx FPGA XC7K325T 900 on the Vivado HLS platform for synthesis, only 10% of the LUT, 5% of FF, 5% of BRAM, and 6% of DSP in FPGA resources are consumed to meet the design requirements. © 2021 IEEE.

关键词： Field programmable gate arrays (FPGA)

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Study of the Sensing Characteristics of Irradiated Fiber Bragg Gratings and Fabry-Perot Interferometers Under Gamma Radiation

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Photonic Sensors 2022年第1期12卷 91-98页

作者： Zhuoyue LI Zengling RAN Xianguo QING Zhengxi HE Yaqin XIAO Tingting YANG Xiu HE Jialiang ZHU Peng HE Sijie XU Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China Key Laboratory of Optical Fiber Sensing&Communications(Ministry of Education) University of Electronic Science and Technology of ChinaChengdu 611731China China Aerodynamics Research and Development Center Mianyang 621000China

The sensing characteristics of irradiated fiber Bragg gratings(FBGs)and Fabry-Perot interferometers(FPIs)were investigated under a 2MGy dose of gamma *** study found that the pressure sensitivity of FP sensors after irradiation was stable,while the temperature sensitivity of FBG sensors was unstable,and both wavelengths displayed a *** findings offer the possibility for the application of FP pressure sensors in the gamma radiation environments,and FBG sensors require further research to be suitable for application in the nuclear radiation environments.

关键词： Fiber Bragg gratings Fabry-Perot interferometers gamma radiation

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Effect of Fecral Sublayer Composition on the Microstructure, Mechanical Properties and Corrosion Resistance of Fecral/Ysz Composite Coatings

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SSRN 2023年

作者： Zhu, Changda Qiu, Xi Li, Yuanming Zhang, Wei Yang, Jian Zhong, Yilong Deng, Jiuguo Zhou, Mingyang 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 effect of FeCrAl sublayer composition on the microstructure, mechanical properties and lead-bismuth eutectic (LBE) corrosion behavior of the FeCrAl/YSZ composite coatings were systematically investigated. The results show that the FeCrAl sublayer as a diffusion barrier and bonding layer is beneficial to improve the mechanical properties and corrosion resistance of the coatings. After corrosion, a slow-growing, continuous and protective Al-rich oxide is formed at the interface between the YSZ and FeCrAl sublayer, which can effectively hinder the inward diffusion of oxygen atoms and the outward diffusion of iron atoms. Especially, the Fe12Cr9Al/YSZ coating exhibits the best corrosion resistance even after corrosion at 700°C. The microscopic corrosion mechanism of FeCrAl/YSZ coating is elucidated. © 2023, The Authors. All rights reserved.

关键词： Eutectics

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On the Accuracy and Efficiency of the reactor Operation Digital Twin for Parameter Identification and State Estimation

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SSRN 2023年

作者： Hong, Lizhan Gong, Helin Ji, Hongjun Lu, Jialiang Li, Han Li, Qing Paris Elite Institute of Technology Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

Accurate and efficient online parameter identification and state estimation are crucial to leveraging Digital Twin simulations for optimizing the operation of near-carbon-free nuclear energy systems. In previous works, we have developed the idea of reactor Operation Digital Twin (RODT). However, non-differentiabilities and discontinuities arise when employing some machine learning based surrogate forward models, challenging traditional gradient-based inverse methods and their variants. This study investigates deterministic and metaheuristic algorithms and further develops hybrid algorithms to address such issues. An efficient modular RODT software framework is presented incorporating these methods into its post-evaluation module for comprehensive comparison. Methods are rigorously assessed based on convergence profiles, stability with respect to noise, and computational performance. Numerical results demonstrate that the hybrid KNNLHS algorithm delivers the optimal balance of accuracy and efficiency for real-time online applications. Meanwhile, algorithms like FSA, DE and ADE exhibit slower yet highly accurate performance. This work advances RODT methodologies to harness machine learning and systems modelling for improved reactor monitoring, systematic diagnosis of off-normal events, lifetime management strategies, etc. The developed modular software and novel optimization methods presented offer pathways to realize the full potential of RODT for transforming energy engineering practices. © 2023, The Authors. All rights reserved.

关键词： State estimation

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Flexible liquid metal electromagnetic shielding materials

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science China(Technological sciences) 2023年第10期66卷 2757-2774页

作者： BAI YunLong ZHANG Jie ZHANG MingKuan RAO Wei Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Beijing Key Lab of CryoBiomedical Engineering and Key Lab of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100039China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China

The demand for flexible shielding has been rapidly growing in recent *** materials using solid metals,carbon materials,or MXenes as shielding units usually have difficulty in combining high shielding and flexibility(stretching and bending characteristics),and thus they gradually fail to meet the shielding needs of flexible ***,shielding materials with both flexibility and high conductivity are urgent to fill this ***-based room temperature liquid metal(LM)is an emerging functional material with a low melting point,low viscosity,low modulus,and easy ***,due to wettability and compatibility issues,it is difficult to apply bulk LMs directly in the field of electromagnetic shielding(EMS).The article reviews the fabrication methods,performance,and applications of LMs EMS materials from three perspectives:Macroscopic LMs,micro/nano-LMs,and LM-based *** gallium-based liquid EMS materials demonstrate the characteristics of high shielding performance with stretchability and a wide shielding *** this review,different types of gallium-based LM materials are described from macroscopic to microscopic,from liquid to semi-solid,from high density to low density,from room temperature to ultra-low temperature,and from monolayer structure to multilayer *** prospect of LM materials as amorphous high-performance EMS materials is demonstrated in various applications,such as mobile communication,astronomical observation,radar,and medical detection,showing tremendous potential in the EMS field.

关键词： liquid metal electromagnetic shielding flexibility

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Numerical simulation of a UAV impacting engine fan blades

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Chinese Journal of Aeronautics 2021年第10期34卷 177-190页

作者： Jingyu YU Bingjin LI Jun LIU Naidan HOU Yingchun ZHANG Yafeng WANG Yulong LI School of Aeronautics Northwestern Poly technical UniversityXi'an 710072China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China Shanghai Aircraft Airworthiness Certification Center of CAAC Shanghai 200335China China Aircraft Strength Research Institute Xi'an 710065China

A 3D digital model of a small Unmanned Aerial Vehicle(UAV)is obtained by using the method of scanning reverse modeling and joint mapping.A numerical simulation of a small UAV strikes on rotary engine blades,presented in this paper,was performed with a Transient Nonlinear Finite Element code PAM-CRASH software.A test of motor strike on plate was developed and the dynamic response of the plate were obtained to validate the numerical simulation method of a UAV strike on *** on this,dynamic damage response caused by UAV on the engine blades were *** is indicated that the impact process between the UAV and a single blade can be divided into two typical stages:cutting and *** mainly leads to the failure of the leading edge material,and impact mainly leads to the plastic deformation of the *** the same time,it is compared with the damage impacted by bird with the same *** the same mass of bird and UAV,the damage caused by UAV striking fan blade is more serious,and 1.345 kg UAV striking fan blade of typical civil aviation engine is enough to cause damage to flight safety.

关键词： Airworthiness Bird impact Engine fan blade Explicit dynamics UAV

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The application of Deep Reinforcement Learning in Coordinated Control of Nuclear reactors 4

The application of Deep Reinforcement Learning in Coordinate...

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

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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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UDC: a unified neural divide-and-conquer framework for large-scale combinatorial optimization problems 24

UDC: a unified neural divide-and-conquer framework for large...

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Proceedings of the 38th International Conference on Neural Information Processing systems

作者： Zhi Zheng Changliang Zhou Xialiang Tong Mingxuan Yuan Zhenkun Wang School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China Huawei Noah's Ark Lab Shenzhen China

ISBN: (纸本)9798331314385

Single-stage neural combinatorial optimization solvers have achieved near-optimal results on various small-scale combinatorial optimization (CO) problems without requiring expert knowledge. However, these solvers exhibit significant performance degradation when applied to large-scale CO problems. Recently, two-stage neural methods motivated by divide-and-conquer strategies have shown efficiency in addressing large-scale CO problems. Nevertheless, the performance of these methods highly relies on problem-specific heuristics in either the dividing or the conquering procedure, which limits their applicability to general CO problems. Moreover, these methods employ separate training schemes and ignore the interdependencies between the dividing and conquering strategies, often leading to sub-optimal solutions. To tackle these drawbacks, this article develops a unified neural divide-and-conquer framework (i.e., UDC) for solving general large-scale CO problems. UDC offers a Divide-Conquer-Reunion (DCR) training method to eliminate the negative impact of a sub-optimal dividing policy. Employing a high-efficiency Graph Neural Network (GNN) for global instance dividing and a fixed-length sub-path solver for conquering divided sub-problems, the proposed UDC framework demonstrates extensive applicability, achieving superior performance in 10 representative large-scale CO problems. The code is available at https://***/CIAM-Group/NCO_code/tree/main/single_objective/UDC-Large-scale-CO-master

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