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Research Square 2021年

作者： Li, Shuangbao Wang, Tingting Chen, Jianen Research Institute of Science and Technology Innovation Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A new highly efficient elastic-impact bistable nonlinear energy sink (EI-BNES) based on magnetic-elastic impacts with negative stiffness and bistability is proposed and optimized through global dynamical analysis. The EI-BNES has better robustness and higher energy dissipation rates with nearly more than 96.5% for broadband impulsive excitations than the traditional cubic NESs and single bistable NESs. The structure of negative stiffness impacts is realized by reasonable layout of permanent ring magnets and springs. A two-degree-of-freedom (two-DOF) elastic-impact system is established to describe the coupled nonlinear interaction between the main structure and the attached EI-BNES. A global Melnikov reduction analysis (GMRA) is proposed to study global dynamics and homoclinic bifurcations of the reduced two-dimensional subsystem, which is used to explain the mechanism of nonlinear targeted energy transfer (TET) and detect the threshold of impulsive amplitudes of EI-BNES for in-well and compound motions between in-well and cross-well resonance responses. A special type of saddle-center equilibrium points is also found in the non-smooth system of the EI-BNES and can be used to effectively increase the energy dissipation rates. The optimal design criterion of the tuned EI-BNES for better dissipation performance is also first discussed based on the GMRA and numerical techniques for calculating the Melnikov function of the non-smooth systems. The effectiveness of the analytical GMRA is also verified by numerical simulations. © 2021, CC BY.

关键词： Stiffness

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Limit load estimation for finite plates with semi-elliptical defects under tensile loading

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Journal of Physics: Conference Series 2021年第1期1777卷

作者： K K Shi X L Fu H Xie X J Shao J Tian Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

The ASME code allows the designer to circumvent many of the problems arising in design by elastic analysis by performing plastic or limit analysis of the component. Unlike elastic analysis, these analyses take account of the redistribution of stress upon yield. In limit analysis, the calculation of the limit load for finite plate with different semi-elliptical defects is an important stage for mechanical safety evaluation. The elastic compensation technique proposed by Mackenzie can be used to provide the limit load of a structure with a finite element method and aims at producing a suitable stress filed for the lower bound theory. In the present study, it is assumed that the finite plate exists three kinds of semi-elliptical cracks with low aspect ratio a/c (a/c=0.1, 0.5 and 1.0), respectively. The improved elastic compensation technique realized by finite element method is applied in the limit load estimation. At last, the results show that the improved elastic compensation technique can be used to obtain the limit value for the finite plate with different semi-elliptical defects under tensile loading. Moreover, the improved elastic compensation technique can be easily implemented in any finite element method and enables the limit load for any complex structure to be obtained swiftly.

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Comparisons of Subgrid-Scale Models for OpenFoam Large- Eddy Simulation

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Journal of Physics: Conference Series 2021年第4期1802卷

作者： Zhipeng Feng Huanhuan Qi Xuan Huang Shuai Liu Jian Liu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

OpenFOAM is a free, open-source software package that can be used for the solutions of computational fluid dynamics and simulation of various fluid flow processes. Nevertheless, OpenFOAM still lacks default settings and a large number of different numerical schemes and turbulent models should be validated. In this paper, the unsteady flow around a cylinder (Re=3900) is calculated by the large eddy simulation of OpenFOAM. The predictions include the drag and lift coefficient, the pressure distribution around the cylinder, the velocity distribution and Reynolds stress distribution in the wake region, as well as the prediction of the recirculation length and separation angle. Thanks to several simulations, these five subgrid-scale (SGS) models are compared and studied: The Smagorinsky SGS model, wall adaptive local eddy visibility SGS model, dynamic SGS model with Lagrangian averaging, dynamic one equation eddy visibility model, one equation eddy visibility model. The numerical results are verified with the published experimental data.

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Accelerated performance degradation test and analysis of high-temperature strain gauges

Accelerated performance degradation test and analysis of hig...

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13th International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering (QR2MSE 2023)

作者： L. Li Z. Wang N. Yang Q. Wu H. Wang Z. Mao K. Ren Q. Wang Y. Wang National Key Laboratory of Strength and Structural Integrity School of Aeronautic Science and Engineering Beihang University Beijing People's Republic of China Shenyang Aircraft Design and Research Institute Shenyang People's Republic of China Institute of Spacecraft System Engineering China Academy of Space Technology Beijing People's Republic of China Navigation Instrument Research Institute Tianjin People's Republic of China Beijing Institute of Control Engineering Beijing People's Republic of China

ISBN: (数字)9781839539275

With the extension of the service time of the structure and the worse service temperature conditions, the drift problem of hightemperature strain gauges gradually becomes prominent. This research aims to address the issue of the drift of measurement results because of the performance degradation of high-temperature strain gauges, and investigate the drift law under different temperatures considering complex service environments. In this paper, a combination of experimental research and theoretical analysis is utilized to design and conduct the accelerated performance degradation test on high-temperature strain gauges. Based on the result of the test, an accelerated performance degradation model is developed using the Wiener process and Arrhenius model. Finally, estimation curves for the average value and percentile value of the performance parameters of the hightemperature strain gauges are obtained, which demonstrates that the established accelerated performance degradation model can reasonably describe the degradation law. Additionally, the established accelerated performance degradation model enables effective analysis and compensation of gauge drift at any temperature.

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Finite Element Analysis of Series Elastic Actuator for Exoskeleton Robot Joint 17

Finite Element Analysis of Series Elastic Actuator for Exosk...

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17th IEEE International Conference on Mechatronics and Automation, ICMA 2020

作者： Xi, Pengyu Ge, Weimin Zhang, Sen Zhang, Zhili Zielinska, Teresa Tianjin University of Technology Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin300384 China Tianjin Sino-German University of Applied Science Intelligent Manufacturing College Tianjin300384 China Institute of Aeronautics and Applied Mechanics Warsaw University of Technology Warsaw00665 Poland

ISBN: (纸本)9781728164151

The finite element simulation for the joints of an exoskeleton robot is conducted in this paper. Using software OpenSim to simulate the normal walking gait of the human body, the motion angle and moment of the human hip, knee and ankle joints are obtained. Using the obtained data as the input parameters in the finite element simulation of the simulation software Ls-dyna, the strain diagrams and contact force curves of the circular roller and cam disk were obtained. In this study, three commonly used materials are selected: alloy steel, ductile iron and hard aluminum alloy. Finally, the effects of different materials on the key components of the series elastic actuator are studied. © 2020 IEEE.

关键词： Finite element method

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Experimental study on corrugated plate dryer in steam generator under hot working conditions

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iscience 2025年第6期28卷 112581页

作者： Li, Ru Wang, Bo Wang, Gongqing Ye, Xuan Bo, Hanliang Tian, Ruifeng Wei, Xiong Institute of Nuclear and New Energy Technology of Tsinghua University Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Beijing 100084 China College of Nuclear Science and Technology Harbin Engineering University Heilongjiang Harbin 150001 China Wuhan Second Ship Design and Research Institute Hubei Wuhan 430205 China

In advanced pressurized water reactors, the corrugated plate dryer (CPD) is essential for ensuring the safety and efficiency of nuclear power plants by influencing steam quality in the separation system of steam generators. While previous research has focused on cold-condition experiments, this study addresses the complexities of hot operational conditions, which are more representative of real-world scenarios. By investigating the effects of CPD structural parameters on separation performance, the research establishes an experimental platform that reveals a critical plate spacing where the CPD's critical velocity (CV) peaks. Additionally, the study explores the internal gas flow dynamics, demonstrating that increased recirculation along the plate walls significantly impacts flow velocity. These findings contribute to a deeper understanding of CPD performance under realistic conditions, enhancing the reliability and efficiency of nuclear power generation. © 2025 The Authors

关键词： Computational mechanics Heat transfer Mechanical engineering

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Synthetic gene circuits moving into the clinic

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Quantitative Biology 2021年第1期9卷 100-103页

作者： Shuguang Peng Huiya Huang Ping Wei Zhen Xie MOE Key Laboratory of Bioinformatics and Bioinformatics Division Center for Synthetic and System BiologyDepartment of AutomationBeijing National Research Center for Information Science and TechnologyTsinghua UniversityBeijing 100084China Beijing Syngentech Co. LtdZhongguancun Life Science ParkChangping DistrictBeijing 102206China Center for Gene Circuit and Cell Design Shenzhen Institute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055ChinaCenter for Quantitative BiologyAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China

On November 28th 2020,SyngenTech,a China-based biotechnology company,announced that the company’s leading oncolytic virotherapeutic product,SynOVl.l,was approved for clinical trial by the *** and Drug *** synthetic bacterial or cell therapy[1,2],this is the first introduction of a viral therapy engineered using synthetic gene circuits into the *** with the clinical development of variable living therapeutics,we anticipate that synthetic gene circuits will receive increasing attention as a revolutionary technology to improve disease-treatment efficacy.

关键词： clinic clinical Together

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Generative assimilation and prediction for weather and climate

arXiv

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arXiv 2025年

作者： Yang, Shangshang Nai, Congyi Liu, Xinyan Li, Weidong Chao, Jie Wang, Jingnan Wang, Leyi Li, Xichen Chen, Xi Lu, Bo Xiao, Ziniu Boers, Niklas Yuan, Huiling Pan, Baoxiang Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China School of Atmospheric Sciences Key Laboratory of Mesoscale Severe Weather Ministry of Education Nanjing University Nanjing China Earth System Modelling School of Engineering and Design Technical University of Munich Munich Germany Complexity Science Potsdam Institute for Climate Impact Research Potsdam Germany Chinese Academy of Meteorological Sciences Beijing China College of Meteorology and Oceanography National University of Defense Technology Changsha China School of Mathematical Sciences Peking University Beijing China Chongqing Research Institute of Big Data Peking University Chongqing China China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate Center Beijing China Xiong’an Institute of Meteorological Artificial Intelligence Xiong’an China

Machine learning models have shown great success in predicting weather up to two weeks ahead, outperforming process-based benchmarks [1–4]. However, existing approaches mostly focus on the prediction task, and do not incorporate the necessary data assimilation. Moreover, these models suffer from error accumulation in long roll-outs, limiting their applicability to seasonal predictions [5] or climate projections [6]. Here, we introduce Generative Assimilation and Prediction (GAP), a unified deep generative framework for assimilation and prediction of both weather and climate. By learning to quantify the probabilistic distribution of atmospheric states under observational, predictive, and external forcing constraints, GAP excels in a broad range of weather-climate related tasks, including data assimilation, seamless prediction, and climate simulation. In particular, GAP is competitive with state-of-the-art ensemble assimilation, probabilistic weather forecast and seasonal prediction, yields stable millennial simulations, and reproduces climate variability from daily to decadal time scales. © 2025, CC BY-NC-SA.

关键词： Prediction models

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Numerical analyses and experimental verification on multiphase flow measurements using a gamma-ray densitometer with blind-tee mixing 27

Numerical analyses and experimental verification on multipha...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Ma, Yugao Cui, Yinghuan Hao, Yisheng Huang, Shanfang Pan, Yanzhi Yu, Hongxing Department of Engineering Physics Tsinghua University Beijing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9784888983051

Gas-liquid two-phase flow widely exists in nuclear industry, where the heat flux is quite high. Accurate predictions of key parameters such as void fraction and gas volume fraction are important to the insurance of reactor safety operation. However, the accuracy of most multiphase flowmeters is flow-pattern dependent. A common way to homogenize the gas-liquid mixture and to eliminate the flow pattern effects is to install a blind-tee upstream of the flow measurement section to transform the horizontal flow to vertical upward flow. It is therefore of great interest to verify the effectiveness of flow mixing caused by blind-tee via experiments or simulation. In this study, the three-dimensional transient numerical simulation on gas-liquid two-phase flow was carried out by a commercial CFD software Fluent, using VOF model as multiphase model and Realizable k-Ε model as turbulence model. The results show that the flow develops from centrifugal flow to homogenous flow after passing around the bend and recovers its intermittent nature further downstream. CFD simulation analysis shows that there is a relatively ideal mixing effect after about 7 pipe diameters downstream. Therefore, the complexity of horizontal flow and intermittent flow are avoided by means of device design and measurement position optimization, which simplifies the measurement and calculation model. A flow-pattern based flow rate model is established by introducing the homogeneous-degree evaluation factor. The formula is simple and yet accurate. The relative average error of the model for predicting the total mass flow rate is within 2.66%. Copyright © 2018-2019 by JSME

关键词： Flowmeters

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Research on Optimization of key Parts of Nuclear reactor Based on Finite Element Simulation

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IOP Conference Series: Earth and Environmental science 2021年第3期632卷

作者： Bo Yang Tianda Yu Qiang Deng Cong Chen Fengshou Zhang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institution of China Sichuan ChengDu 610041 China

In view of the higher technical requirements of the third generation PWR for the control rod drive mechanism (CRDM), China's third generation nuclear reactor CRDM hook parts are designed to multi-tooth hook with wear-resistant surfacing. The surfacing welding process is simulated and optimized based on finite element simulation, and reasonable welding process and parameters are determined by simulation results in this *** to the optimized welding process, the parts are trial-produced, and the parts of the hook are subjected to metallographic inspection, hardness test and thermal life test. The results show that the optimized hook parts have high hardness and wear resistance, and meet the requirements of the third generation PWR nuclear power plant.

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