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Evolution and Characteristics of Defect Clusters in H2+ Irradiated Al-Based Gd2o3-W Composites Used as Spent Fuel Shielding Materials

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SSRN 2023年

作者： Wang, Zuojiang Cao, Ziqi Wu, Mengjie Li, Yuanming Ran, Guang College of Energy Xiamen University Fujian Province Xiamen City361102 China Science and Technology on Reactor System Design Technology Laboratory Chengdu610213 China Fujian Provincial Nuclear Energy Engineering Technology Research Center Xiamen361102 China Nuclear Power Institute of China Chengdu610213 China

Al-based composites containing high neutron absorption cross section elements are the most promising shielding materials for spent fuel storage, but their irradiation performance is the key to their long-term service stability. In the present work, an in-situ study on the evolution and characteristics of irradiation defect clusters including dislocation loops, gas bubbles and hydrogen platelets in Al-based Gd2O3-W composites during 30 keV H2+ irradiation was carried out in a transmission electron microscope and analyzed in detail. The delamination of bubbles and the formation of tunnel structure in Al matrix were found for the first time. Hydrogen platelets in Al5W particles was first observed, and their formation and evolution and corresponding mechanism were investigated in detail. Platelets with different orientation had different growth rates, and the relationship between growth rate and dose was constructed. Besides, the irradiation-induced increment of yield strength in Al matrix was estimated. This study will provide new insights for the design and development of new Al-based rare earth composites with high resistance to irradiation damage. © 2023, The Authors. All rights reserved.

关键词： Platelets

The dynamic compressive properties of magnetorheological plastomers: enhanced magnetic-induced stresses by non-magnetic particles

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Journal of Materials science & technology 2022年第7期102卷 195-203页

作者： Haoming Pang Zhenbang Xu Longjiang Shen Jun Li Junshuo Zhang Zhiyuan Li Shouhu Xuan Xinglong Gong 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 China(USTC)Hefei 230027China Anhui Weiwei Rubber Parts Group Co.Ltd Tongcheng 231400China CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Hunan Bogie Engineering Research Center Zhuzhou 412000China

In this research, a series of hollow glass powder(HGP) reinforced magnetorheological plastomers(MRPs)were prepared to improve the impact resistance of the materials, and the dynamic compressive properties of MRPs under high strain rate were investigated by using a split Hopkinson pressure bar(SHPB)system equipped with a customized magnetic device. Experimental results showed the HGPs greatly enhanced the yield stresses of the MRPs. Especially, for MRPs with 9 vol.% carbonyl iron powders(CIPs), the magnetic-induced yield stress increased from 7.3 MPa to 17.1 MPa(134% increased) by adding 18 vol.%HGPs. The particle structures in MRPs were further simulated and the corresponding intergranular stress was calculated to study the enhancement effect of HGPs. The simulated results showed that more compact structures were formed with the excluded volume caused by secondary HGPs, so the yield stresses of the MRPs increased under a magnetic field. However, when the mass ratio of HGP to CIP was larger than 0.67, HGPs would hinder the formation of chain-like structures and reduce the magneto-mechanical properties. As a result, the replacing of CIPs by HGPs was proven to be an excellent strategy to improve the dynamic properties of MRPs.

关键词： Particle-reinforced composites Stress/strain curves Microstructures Impact behavior Mechanical properties

Deep Learning-Enabled ISAC-OTFS Pre-equalization design for Aerial-Terrestrial Networks

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arXiv

arXiv 2024年

作者： Wang, Weihao Guo, Jing Wang, Siqiang Wang, Xinyi Yuan, Weijie Fei, Zesong the School of Information and Electronics Beijing Institute of Technology Beijing100081 China the School of System Design and Intelligent Manufacturing The Shenzhen Key Laboratory of Robotics and Computer Vision Southern University of Science and Technology Shenzhen518055 China

Orthogonal time frequency space (OTFS) modulation has been viewed as a promising technique for integrated sensing and communication (ISAC) systems and aerial-terrestrial networks, due to its delay-Doppler domain transmission property and strong Doppler-resistance capability. However, it also suffers from high processing complexity at the receiver. In this work, we propose a novel pre-equalization based ISAC-OTFS transmission framework, where the terrestrial base station (BS) executes pre-equalization based on its estimated channel state information (CSI). In particular, the mean square error of OTFS symbol demodulation and Cramér-Rao lower bound of sensing parameter estimation are derived, and their weighted sum is utilized as the metric for optimizing the pre-equalization matrix. To address the formulated problem while taking the time-varying CSI into consideration, a deep learning enabled channel prediction-based pre-equalization framework is proposed, where a parameter-level channel prediction module is utilized to decouple OTFS channel parameters, and a low-dimensional prediction network is leveraged to correct outdated CSI. A CSI processing module is then used to initialize the input of the pre-equalization module. Finally, a residual-structured deep neural network is cascaded to execute pre-equalization. Simulation results show that under the proposed framework, the demodulation complexity at the receiver as well as the pilot overhead for channel estimation, are significantly reduced, while the symbol detection performance approaches those of conventional minimum mean square error equalization and perfect CSI. Copyright © 2024, The Authors. All rights reserved.

关键词： Channel estimation

Microstructure and impact toughness of 16MND5 reactor pressure vessel steel manufactured by electrical additive manufacturing

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Journal of Iron and Steel Research International 2020年第8期27卷 992-1004页

作者： Xi-kou He Chang-sheng Xie Li-jun Xiao Ying Luo Di Lu Zheng-dong Liu Xi-tao Wang Institute for Special Steels China Iron and Steel Research InstituteBeijing 100081China Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610041SichuanChina Southern Additive Science and Technology Co. Ltd.Foshan 528225GuangdongChina

Electrical additive manufacturing can improve manufacturing efficiency and reduce the cost of 16MND5 reactor pres-sure vessel steel. Impact tests were conducted to compare the impact toughness of 16MND5 steels manufactured by the electrical additive manufacturing and conventional forging, respectively. It is found that the impact toughness of electrical additive manufacturing specimen was slightly higher than that of conventional forging specimen. The characterizations of microstructure show that there were large ferrites and carbides in electrical additive manufacturing specimen. The fracture mechanisms of electrical additive manufacturing specimen were that microvoids or microcracks were prone to nucleate at the large ferrite/bainite interface and large carbide/bainitic ferrite interface, where the stress concentration was high. In addi-tion, the block size and high-angle grain boundaries played a vital role in hindering crack propagation of electrical additive manufacturing specimen, helping to improve the impact energy and leading to a low ductile–brittle transition temperature. The results suggest that the electrical additive manufacturing technology was an effective method to enhance the impact toughness of 16MND5 steel.

关键词： Electrical additive manufacturing 16MND5 steel Impact toughness Fracture High-angle grain boundary

High spectro-temporal compression on a nonlinear CMOS-chip

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Light(science & Applications) 2021年第7期10卷 1347-1361页

作者： Ju Won Choi Ezgi Sahin Byoung-Uk Sohn George F.R.Chen Doris K.T.Ng Anuradha M.Agarwal Lionel C.Kimerling Dawn T.H.Tan Photonics Devices and System Group SUTD-MIT International Design CenterSingapore University of Technology and DesignSingapore 487372Singapore Institute of Microelectronics A*STAR(Agency for ScienceTechnology and Research)2 Fusionopolis Way#08-02Innovis TowerSingapore 138634Singapore Microphotonics Center Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA Materials Research Laboratory Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA Department of Materials Science and Engineering Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA

Optical pulses are fundamentally defined by their temporal and spectral *** ability to control pulse properties allows practitioners to efficiently leverage them for advanced metrology,high speed optical communications and attosecond ***,we report 11×temporal compression of 5.8 ps pulses to 0.55 ps using a low power of 13.3 *** result is accompanied by a significant increase in the pulse peak power by 9.4×.These results represent the strongest temporal compression demonstrated to date on a complementary metal–oxide–semiconductor(CMOS)*** addition,we report the first demonstration of on-chip spectral compression,3.0×spectral compression of 480 fs pulses,importantly while preserving the pulse *** strong compression achieved at low powers harnesses advanced on-chip device design,and the strong nonlinear properties of backend-CMOS compatible ultra-silicon-rich nitride,which possesses absence of two-photon absorption and 500×larger nonlinear parameter than in stoichiometric silicon nitride *** demonstrated work introduces an important new paradigm for spectro-temporal compression of optical pulses toward turn-key,on-chip integrated systems for all-optical pulse control.

关键词： pulse optical nonlinear

An Adaptive Bionic Sensor: Enhancing Ankle Joint Tracking with High Sensitivity and Superior Cushioning Performance

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SSRN 2024年

作者： Jin, Jianqiao Zhang, Chen Zhao, Jianyuan Yu, Minghan Lei, Ming Jin, Chun Yin, Rui Zhao, Weiwei Sauvage Laboratory for Smart Materials The School of Integrated Circuit Harbin Institute of Technology Shenzhen518055 China Shenzhen Key Laboratory of Flexible Printed Electronics Technology Harbin Institute of Technology Shenzhen518055 China State Key Laboratory of Advanced Welding & Joining Harbin Institute of Technology Harbin150001 China Human-Computer Interaction Design Lab School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China

Flexible sensors are renowned for their rapid responsiveness, high flexibility, and outstanding mechanical properties, making them ideal for applications in wearable devices, sports and health monitoring, and human-machine interfaces. To enhance the sensing performance of these flexible sensors, researchers have drawn inspiration from nature, creating various bionic microstructures. However, these structures often manifest in the macroscopic form of thin films, which do little to improve impact resistance and joint protection. In response, this work achieves a highly sensitive and impact-resistant pressure sensor by integrating bionic principles at both micro and macro levels. Specifically, at the micro level, a muscle-like hydrogel system consisting of MXene nanosheets incorporated into the double network of polyvinyl alcohol and sodium alginate matrix is selected. At the macro level, the bionic prototypes of mimosa leaves and durian spikes with good energy absorption structure, together with octopus’ sucker with good adsorption capacity are selected, and the synergistic construction of the three structures is realized through 3D printing methods. The obtained sensor has an appropriate response range, sensitivity and stability. More importantly, the displacement deformation of the hydrogel can be reduced by 91.22%, while its adhesion strength can be increased by 57.5% compared to the unstructured hydrogel. As a proof-of-concept, the proposed bionic flexible sensor can be used to monitor the motion status of the human ankle joint in real-time, thereby assisting users in making real-time judgments on gait health. © 2024, The Authors. All rights reserved.

关键词： Sodium alginate

Experimental Study on Flow Patterns in Narrow Rectangular Channels

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SSRN 2022年

作者： Lv, Xindi Zhang, Dalin Song, Gongle Su, Guanghui Tian, Wenxi Qiu, Suizheng 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 Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

Plate fuel elements are commonly used in compact nuclear reactors due to the advantages of high fuel consumption. In this paper, the two-phase flow pattern in the coolant channel of plate fuel elements, i.e. the rectangular narrow channel was studied. Visualization flow pattern experiments of upward steam-water two-phase flow in narrow rectangular channels, 745mm long and 67mm wide with gap widths of 1.3mm and 1.9mm, were investigated. The experiments were performed in the conditions of pressure ranging from 1 to 2MPa, mass flow rate ranging from 200 to 1500kg/(m2 ⋅s), inlet subcooling ranging from 20~100°C and tilt angle ranging from 0~ 45°. Three flow patterns, consisting of bubble flow, churn flow and annular flow, were obtained in a wide range of thermal parameters. Flow patterns maps were plotted and the influences of pressure, mass flow rate, inlet subcooling, channel gap and tilt angle on the flow pattern transformation of narrow rectangular channel were studied. This study is of great significance for investigating the subsequent heat transfer process of two-phase flow in compact nuclear reactors. © 2022, The Authors. All rights reserved.

关键词： Two phase flow

Sensitivity Study of Thermal Hydraulics to Corrosion of Heat Exchange Tubes in Steam Generator

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SSRN 2022年

作者： Wang, Weibing Cheng, Kun Wang, Bo Zhang, Meng 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 Institute of China Chengdu610213 China

A leakage accident occurs in the circulating water system in PWRs, impurity ions enter the SG with the secondary circuit feed water and cause electrochemical corrosion of the heat transfer tubes(HTTs). Based on the hide out and return mathematical model in the SG, a coupled mathematical model of mass transfer-electromigration-hydrodynamics of impurity ions in the secondary boiling channel of SG is deduced. The accuracy of the mathematical model is verified by experiments, and the effects of heat flux density ( Pe q ), flow velocity ( Pe u ), impurity ion concentration ( Pe c ) and relative solubility of impurity ions ( K p ) on impurity ions migration and electrochemical corrosion are analyzed and discussed. The results show that P e q mainly controls the diffusion of impurity ions and thus affects the migration rate of impurity ions, and the mass transfer of impurity ions driven by Pe q can enhance the reduction of H + , thereby accelerating the corrosion rate of HTTs. The synergistic effect of convective mass transfer and electromigration during impurity ions migration is mainly affected by Pe u , and the electrochemical corrosion of the surface of HTTs is mainly controlled by charge transfer with the increase of Pe u . The Pe c on the surface of HTTs changes linearly with time, and the corrosion rate increases with the increase of Pe c . The corrosion rate of HTTs is proportional to K p , and K p is a main factor that causes different corrosion rates in different location of HTTs. In this paper, a coupled model for the sensitivity of thermal-hydraulic parameters ( Pe q , Pe u , Pe c and K p ) in SG to electrochemical corrosion of HTTs is proposed for the first time. The research results can provide important support for the development of corresponding response strategies, schemes for the life prediction of HTTs and the safety maintenance of nuclear power plants. © 2022, The Authors. All rights reserved.

关键词： Steam generators

Thermionic Conversion Performance Analysis of the Single-Cell Thermionic Fuel Element Based on Froba-Thermion Code

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SSRN 2022年

作者： Lu, Kailin Yao, Hao He, Yanan Wu, Yingwei Zhang, Jing Liao, Haoyu Su, Guanghui H. Qiu, Suizheng School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

The thermionic conversion performance of the single-cell thermionic fuel element (TFE) is influenced by fuel mass transfer and other parameters. With the consideration of current flow and heat transfer, the thermionic conversion model and the modified heat transfer model were implemented in FROBA-THERMION. Afterward, both implemented models were verified by comparing with experiments or KATET calculation results. Further, a steady-state performance simulation of the single-cell TFE was carried out. The results indicate that the thermionic conversion efficiency will be decreased due to the emitter temperature flattening caused by fuel mass transfer. In addition, the influence of several key parameters on thermionic conversion efficiency and measures to improve the thermionic conversion efficiency were analyzed. © 2022, The Authors. All rights reserved.

关键词： Mass transfer