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SSRN 2024年

作者： Kang, Zehang Wang, Sipeng Du, Peng Chen, Jin Su, Zhen Zhuang, Kun Department of Nuclear Science and Technology Nanjing University of Aeronautics and Astronautics JiangSu Nanjing211106 China Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautics Nanjing University of Aeronautics and Astronautics China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The potential for flow instability in passive residual heat removal systems (PRHRS) to result in equipment damage underscored the necessity for the development of effective mitigation strategies. In order to reduce the flow instabilities that occurs in the PRHRS, the idea of a fluctuation attenuation scheme based on a spring vibrator structure had been proposed. The structure was based on pressure pulsation attenuator in hydraulic systems and had been optimized. A model of a spring vibrator fluctuation attenuation pipe section was developed and its fluctuation attenuation effect was verified under specific parameters. Such as branch pipe length, cavity cross-sectional area, spring vibrator position, spring vibrator stiffness coefficient, and piston mass. The impact of these factors on fluctuation attenuation was investigated. The results demonstrated that, under identical inlet fluctuation conditions, the fluctuation peak at outlet of the pipe containing spring vibrator structure decreased. The optimization of the above parameters had been demonstrated to enhance the fluctuation removal effect of the spring vibrator structure. This study presented a novel approach to relieve flow instability in PRHRS. © 2024, The Authors. All rights reserved.

关键词： Vibrators

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Experimental Study on Turbulent Characteristics of Dispersed Bubbly Flow in a Narrow Rectangular Channel by Two-Phase Piv

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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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Corrosion Mechanisms and Differences of Inconel 617 and Incoloy 800h Under High-Temperature Air Ingress Accident

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SSRN 2024年

作者： Li, Haoxiang Yan, Dapeng Li, Guodong Tian, Changqing An, Jiayi Tan, Jiaqi Zheng, Wei Du, Bin Yin, Huaqiang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China State Key Laboratory of Advanced Nuclear Energy Technology Nuclear Power Institute of China Chengdu China Institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing China Tsinghua University China

In the high-temperature operation of very high-temperature gas-cooled reactors (VHTRs), "microclimate reaction" are one of the key corrosion reactions of concern. This study investigates the corrosion behavior and mechanisms of the two mainstream high-temperature alloys, Incoloy 800H and Inconel 617, under minor air ingress accidents. The main focus is on comparing and analyzing the "microclimate reaction" corrosion behavior and mechanisms of the two alloys, as well as exploring changes in their mechanical properties. The results show that during the experiment, both alloys primarily underwent oxidation and "microclimate reaction". The double-layer oxide of Cr2 O3 -MnCr2 O4 /MnFe2 O4 and the SiO2 layer on the surface of Incoloy 800H provide good resistance to "microclimate reaction," whereas the single-layer Cr2 O3 oxide on Inconel 617 is not effective in preventing "microclimate reaction". The mechanical property test results indicate that the decarburization caused by "microclimate reaction" does not significantly affect the basic mechanical properties of the alloy. Research on "microclimate reactions" should primarily focus on preventing the oxidation layer from cracking and reducing the time during which the alloy matrix is unprotected by a protective oxide layer. © 2024, The Authors. All rights reserved.

关键词： Gas cooled reactors

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Functional group differentiation of isomeric solvents enables distinct zinc anode chemistry

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Nano Research Energy 2023年第2期2卷 218-228页

作者： Chao Liu Qing Li Yilun Lin Zhiquan Wei Yihan Yang Cuiping Han Minshen Zhu Haiyan Zhang Hongfei Li School of Materials and Energy Guangdong University of TechnologyGuangzhou 510006China Songshan Lake Materials Laboratory Dongguan 523808China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen 518055China Faculty of Materials Science and Engineering/Institute of Technology for Carbon Neutrality Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Research Center for Materials Architecturesand Integration of Nanomembranes(MAIN)TU ChemnitzChemnitz 09126Germany

Electrolytes hold the key to realizing reliable zinc(Zn)*** organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular weights and functional group *** this work,two“isomeric molecules”:1,2-dimethoxyethane(DME)and 1-methoxy-2-propanol(PM),with identical molecular weights but different functional groups,have been studied as co-solvents in electrolytes,which have delivered distinct electrochemical *** and simulative study indicates the dipole moment induced by the hydroxyl groups in PM(higher molecular polarity than ether groups in DME)reconstructs the space charge region,enhances the concentration of Zn^(2+)in the vicinity of Zn anodes,and in-situ derives different solid electrolyte interphase(SEI)models and electrode-electrolyte interfaces,resulting in exceptional cycling ***,the Zn||Cu cell with PM worked over 2000 cycles with high Coulombic efficiency(CE)of 99.7%.The Zn||Zn symmetric cell cycled over 2000 h at 1 mA·cm^(−2),and showed excellent stability at an ultrahigh current density of 10 mA·cm^(−2)and capacity of 20 mAh·cm^(−2)over 200 h(depth of discharge,DOD of 70%).The Zn||sodium vanadate pouch cell with a high mass loading of 6.3 mg·cm^(−2)and a high capacity of 24 mAh demonstrates superior cyclability after 570 *** work can be a good starting point to provide reliable guidance on electrolyte design for practical aqueous Zn batteries.

关键词： functional group isomeric solvents zinc anode solid electrolyte interphase(SEI)model

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Position-and-Force-Sensorless Control Considering Equivalent Mass Matrix and Cross-Coupling Factors 49

Position-and-Force-Sensorless Control Considering Equivalent...

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49th Annual Conference of the IEEE Industrial Electronics Society, IECON 2023

作者： Shimamoto, Keita Murakami, Toshiyuki Yaskawa Electric Corporation Tsukuba Research Laboratory Ibaraki Japan Graduate School of Science and Technology Keio University Yokohama Japan Keio University Department of System Design Engineering Yokohama Japan

ISBN: (纸本)9798350331820

This paper presents a hybrid position/force control with equivalent mass matrices for position-and-force-sensorless manipulators and the evaluation of the control system. Position and force estimation methods in the controller are cascaded to estimate the position and force according to the respective characteristics of the electrical and mechanical systems. The proposed controller is designed to reduce vibration of the force control axes' motion from the cross-coupling factors of the dq-axis inductance, which cause position estimation error, and the cross-coupling effects among control axes from equivalent mass matrices, which expresses the relationship between the workspace force and acceleration. The position estimation based on the voltage equation, including the cross-coupling factors, derives compensation terms of the estimation error. The cross-coupling effects between position and force control axes in the equivalent mass matrices are designed to suppress the undesired force response vibrations. The experimental results show that the proposed system kept contact with an object during the rubbing motion by a 4-degree-of-freedom manipulator without position and force sensors. The utilized equivalent mass matrix reduced the force vibration caused by the vibration of the position estimation. © 2023 IEEE.

关键词： Force control

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Effect of Process and Geometric Parameters on Residual Distortion of Ti-6Al-4V Body-Centered Cubic Lattice Structures in Laser Powder Bed Fusion

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Additive Manufacturing Frontiers 2024年第4期3卷 191-198页

作者： Yupei Tian Jian He Huilin Ren Xinmeng Zha Kaijie Lin Mingdong Zhou Yi Xiong School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen518055China Jiangsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing211106China Shanghai Key Laboratory of Digital Manufacture for Thin-walled Structures School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

The advent of laser powder bed fusion(LPBF)has provided an effective solution for fabricating lightweight structures with intricate designs that cannot be realized using other manufacturing *** structures,however,which feature unique characteristics,pose greater challenges in the LPBF process than solid structures and exhibit more significant *** underlying mechanisms and influencing factors of this distortion remain unclear,presenting a significant research *** study investigates the generation mechanism of residual stress in Ti-6Al-4V lattice structures during LPBF and examines how process and geometric parameters influence residual ***-type cantilever structures with various arm thicknesses and strut diameters were fabricated using different laser powers and scan *** residual distortion after removal from the building substrate was measured using a non-contact coordinate-measuring *** results suggest that increasing the arm thickness,reducing the strut diameter,and employing a scanning pattern with interlayer rotation effectively reduce residual *** these factors,the scanning pattern had the most distinct impact,differing significantly from those affecting solid structures.P2(45°)scanning pattern resulted in the greatest residual distortion,approximately twice that of the least distorted ***,the laser power exerted a minor influence on the distortion of the lattice *** findings provide insights and guidance for fabricating lattice structures using the LPBF process,broadening its applications in aerospace,automotive,and other weight-sensitive industries.

关键词： LPBF Ti-6Al-4V Lattice structures Residual distortion Residual stress

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Broadband Wide-Angle Linear-to-Circular Polarization Converter Based on Metal Strips Loaded Metasurface

Broadband Wide-Angle Linear-to-Circular Polarization Convert...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Wang, Jingwen Deng, Shasha Chen, Weidong Zhang, Zhongxiang Chen, Chang University of Science and Technology of China School of Information Science and Technology Hefei230031 China Hefei Normal University Key Laboratory of Simulation and Design for Electronic Information System Hefei230601 China

ISBN: (纸本)9781665452366

A transmissive broadband wide-angle linear-to-circular polarization converter based on metal strips loaded metasurface is proposed in this paper. The converter is composed of three metallic layers separated by dielectric substrates and the metal strips printed on each layer keep orthogonal to each other. To further investigate the operating mechanism of the design, equivalent circuit models are presented. Moreover, the converter is verified to be effective in polarization conversion through the full-wave simulation. With the insertion loss less than 2 dB and 3 dB, the simulation 3-dB axial ratio (AR) bandwidth keeps 67% and 76%, respectively. Furthermore, at an increased incident angle of 40°, the device can still maintain an AR bandwidth over 47% at 2 dB insertion loss, which manifests the validity and rationality of the converter design. © 2022 IEEE.

关键词： Strip metal

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A Band Stop Decoupling Structure for Circularly Polarized Antennas With Different Intervals

A Band Stop Decoupling Structure for Circularly Polarized An...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Ding, Yuhang Deng, Shasha Chen, Weidong Zhang, Zhongxiang Chen, Chang University of Science and Technology of China School of Information Science and Technology Hefei230031 China Hefei Normal University Key Laboratory of Simulation and Design for Electronic Information System Hefei230601 China

ISBN: (纸本)9781665452366

In this paper, a novel band stop decoupling structure (BSDS) for circularly polarized microstrip antenna array with different intervals to realize mutual coupling reduction is proposed. The BSDS is composed of complementary split-rings resonator (CSRRs) and split-rings resonator (SRRs), where the CSRRs block TM waves by electric resonance and the SRRs block TE waves by magnetic resonance, respectively. The proposed design is verified by the simulation and the results indicate that the isolation enhancement more than 35 dB can be obtained at the center frequency of 3.4 GHz when the center spacing is 0.37 λ0. Futhermore, when the center spacing reduces to 0.26 λ0, the mutual coupling remains below 25 dB. Besides, the BSDS can improve the radiation pattern offset without affecting the gain and the backward radiation of antennas. © 2022 IEEE.

关键词： Magnetic resonance

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NO reduction by carbon-based gases based on coal gasification fractions:NO reduction intermediate identification and kinetic analysis

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Frontiers of Environmental science & Engineering 2025年第3期19卷 175-189页

作者： Xiang Zhang Jian Tian Tanghui Hu Guangyong Yue Xianlong Liu Wen Zhou Xiaohong Liu Xinye Wang Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials Hubei Engineering Research Center for Green Industrialization Technology of Industrial WasteSchool of Materials Science and EngineeringHubei UniversityWuhan 430062China Hubei Huda Tianshu New Energy Materials Industrial Research and Design Institute Co. Ltd.Wuhan 430062China Wuhan Tianshu Dust Removal Equipment Co. Ltd.Wuhan 430062China Engineering Laboratory for Energy System Process Conversion&Emission Control Technology of Jiangsu Province School of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing 210042China

Combining pulverized coal gasifiers with cement kiln production is promising for application in low-cost and efficient NO *** paper presents a pulverized coal gasifier catalytic denitration technique and investigates the homogeneous reduction(by CO and CH_(4))and heterogeneous catalytic reduction(by coke,CaO,MgO,and Fe_(2)O_(3))of NO.A combination of Chemkin simulations and fixed-bed experiments is used to elucidate the reaction pathways and key intermediates of NO reduction by carbon-based *** addition,the activation energies for different catalyst combinations were analyzed via reaction *** results demonstrate that the presence of small amounts of O_(2) inhibits NO reduction by CO but promotes NO reduction by CH_(4).The NCO·radical is essential for the NO reduction process,and the generation of this radical depends on the CH_(4) cleavage intermediate and O·*** and Fe_(2)O_(3) exhibit more significant catalytic effects on NO reduction by carbon-based gases than the other catalysts *** presence of a small amount of O_(2) in the reacting gas mixtures facilitates the NO reduction *** activation energy is reduced to 1.02 kJ/mol,and the NO conversion reaches 99.80%when the catalyst is C+CaO+MgO+Fe_(2)O_(3) and the gas composition is CO+CH_(4)+O_(2).This work provides theoretical support and data recommendations for the use of pulverized coal gasifiers for the denitrification of cement kilns.

关键词： Carbon-based gas Catalytic denitration Coke Kinetic analysis Reaction mechanism

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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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