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Influence of Assembly Parameters on Tensile Behavior of Hybrid CMC and Superalloy Bolted Joints by Progressive Damage Analysis

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Journal of Harbin Institute of technology(New Series) 2021年第3期28卷 53-60页

作者： Chao Lv Feng Li Shuyuan Zhao Qian Sun Mingrui Li Xinyang Sun China Academy of Aerospace Aerodynamics Beijing 100074China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China Shenyang Aircraft Design and Research Institute Aviation Industry Corporation of ChinaShenyang 110000China School of Aeronautics and Astronautics Harbin Institute of TechnologyHarbin 150001China

With the considerable applications of ceramic matrix composites(CMC) in aircraft engineering, the design of CMC bolted joint gains paramount attention because of its capacity to to improve load-bearing efficiency of aircraft key structure. In this work, a 3 D finite element model was established to predict tensile performance and failure modes of single-lap, single-bolt 2 D C/SiC composite, and superalloy joint, which considers the progressive damage behavior of 2 D woven C/SiC composites. On the basis of the developed progressive damage model, a parametric study was carried out to illustrate the effects of bolt preload and bolt-hole clearance on mechanical behaviors of the hybrid bolted joint. It was found that the increase in the value of bolt preload made the failure load grow first and then drop, and the optimum value of bolt preload 5.00 kN generated 56.47% rise in the initial failure load and 22.83% rise in the final failure load for the bolted joint in comparison with zero preload case. As the clearance increased from 0 to 2.00%, the initial and final failure loads respectively declined by 45.88% and 24.02% for 2.00% bolt-hole clearance relative to the neat-fit case. The loss in failure loads can be reduced to compressive stress concentration around the fastening hole-edge area, leading to the appearance of earlier damages by the introduction of increasing bolt hole clearance.

关键词： ceramic matrix composite progressive damage analysis tensile performance bolt preload bolt-hole clearance

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Multi-functional layered double hydroxides supported by nanoporous gold toward overall hydrazine splitting

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Frontiers of Chemical science and Engineering 2024年第1期18卷 61-69页

作者： Yongji Qin Huijie Cao Qian Liu Shaoqing Yang Xincai Feng Hao Wang Meiling Lian Dongxing Zhang Hua Wang Jun Luo Xijun Liu ShenSi Lab Shenzhen Institute for Advanced StudyUniversity of Electronic Science and Technology of ChinaShenzhen 518110China Institute for New Energy Materials and Low-Carbon Technologies School of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured MaterialsSchool of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China Institute for Advanced Study Chengdu UniversityChengdu 610106China China National Coal Group Corporation Beijing 100120China Tianjin Engineering Research Center of Civil Aviation Energy Environment and Green Development School of Transportation Science and EngineeringCivil Aviation University of ChinaTianjin 300300China

Layered double hydroxides have demonstrated great potential for the oxygen evolution reaction,which is a crucial half-reaction of overall water ***,it remains challenging to apply layered double hydroxides in other electrochemical reactions with high efficiency and ***,we report two-dimensional multifunctional layered double hydroxides derived from metalorganic framework sheet precursors supported by nanoporous gold with high porosity,which exhibit appealing performances toward oxygen/hydrogen evolution reactions,hydrazine oxidation reaction,and overall hydrazine *** as-prepared catalyst only requires an overpotential of 233 mV to reach 10 mA·cm^(-2) toward oxygen evolution *** overall hydrazine splitting cell only needs a cell voltage of 0.984 V to deliver 10 mA·cm^(-2),which is far more superior than that of the overall water splitting system(1.849 V).The appealing performances of the catalyst can be contributed to the synergistic effect between the metal components of the layered double hydroxides and the supporting effect of the nanoporous gold substrate,which could endow the sample with high surface area and excellent conductivity,resulting in superior activity and stability.

关键词： layered double hydroxide oxygen evolution reaction hydrazine oxidation reaction overall hydrazine splitting hydrogen production

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Real-time characterization of VOC exposure in a few new residential apartments in Beijing 16

Real-time characterization of VOC exposure in a few new resi...

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16th Conference of the International Society of Indoor Air Quality and Climate: Creative and Smart Solutions for Better Built Environments, Indoor Air 2020

作者： Liu, Yingjun Xie, Di Qiu, Jia Li, Yatai Qu, Yuekun Liu, Ying Zhu, Tong Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing100871 China Beijing Innovation Center for Engineering Science and Advanced Technology Peking University Beijing100871 China

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Jacobi Spectral Collocation Method Based on Lagrange Interpolation Polynomials for Solving Nonlinear Fractional Integro-Differential Equations

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Advances in Applied Mathematics and Mechanics 2018年第6期10卷 1440-1458页

作者： Xingfa Yang Yin Yang Yanping Chen Jie Liu State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082HunanChina Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing&Information Processing of Ministry of EducationSchool of Mathematics and Computational ScienceXiangtan UniversityXiangtan 411105HunanChina School of Mathematical Sciences South China Normal UniversityGuangzhou 510631GuangdongChina Center for Research on Leading Technology of Special Equipment School of Mechanical and Electric EngineeringGuangzhou UniversityGuangzhou 510006GuangdongChina

In this paper,we study a class of nonlinear fractional integro-differential equations,the fractional derivative is described in the Caputo *** the properties of the Caputo derivative,we convert the fractional integro-differential equations into equivalent integral-differential equations of Volterra type with singular kernel,then we propose and analyze a spectral Jacobi-collocation approximation for nonlinear integro-differential equations of Volterra *** provide a rigorous error analysis for the spectral methods,which shows that both the errors of approximate solutions and the errors of approximate fractional derivatives of the solutions decay exponentially in L^(∞)-norm and weighted L^(2)-norm.

关键词： Spectral method nonlinear fractional derivative Volterra integro-differential equations Caputo derivative

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Health benefits from the rapid reduction in ambient exposure to air pollutants after China's clean air actions:progress in efficacy and geographic equality

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National science Review 2024年第2期11卷 103-113页

作者： Tao Xue Ruohan Wang Meng Wang Yanying Wang Dan Tong Xia Meng Conghong Huang Siqi Ai Fangzhou Li Jingyuan Cao Mingkun Tong Xueqiu Ni Hengyi Liu Jianyu Deng Hong Lu Wei Wan Jicheng Gong Shiqiu Zhang Tong Zhu Institute of Reproductive and Child Health National Health Commission Key Laboratory of Reproductive Health/Department of Epidemiology and Biostatistics Ministry of Education Key Laboratory of Epidemiology of Major Diseases(PKU) School of Public Health Peking University Health Science Centre State Environmental Protection Key Laboratory of Atmospheric Exposure and Health Risk Management and Center for Environment and Health Peking University Advanced Institute of Information Technology Peking University Department of Epidemiology and Environmental Health School of Public Health and Health ProfessionsUniversity at Buffalo State Key Joint Laboratory of Environment Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking University Department of Earth System Science Tsinghua University School of Public Health Key Laboratory of Public Health Safety of the Ministry of Education and Key Laboratory of Health Technology Assessment of the Ministry of HealthFudan University College of Land Management Nanjing Agricultural University National&Local Joint Engineering Research Center for Rural Land Resources Use and Consolidation Clean Air Asia

Clean air actions （CAAs） in China have been linked to considerable benefits in public ***,whether the beneficial effects of CAAs are equally distributed geographically is *** high-resolution maps of the distributions of major air pollutants (fine particulate matter[PM2.5]and ozone[O3]) and population,we aimed to track spatiotemporal changes in health impacts from,and geographic inequality embedded in,the reduced exposures to PM2.5and O3from 2013 to *** used a method established by the Global Burden of Diseases *** analyzing the changes in loss of life expectancy（LLE） attributable to PM2.5and O3,we calculated the gain of life expectancy （GLE） to quantify the health benefits of the air-quality ***,we assessed the geographic inequality embedded in the GLE using the Gini index （GI）.Based on risk assessments of PM2.5and O3,during the first stage of CAAs（2013 to 2017）,the mean GLE was 1.87 *** of the sum of the GLE was disproportionally distributed in about one quarter of the population exposed （GI 0.44）.During the second stage of CAAs（2017 to 2020）,the mean GLE increased to 3.94 months and geographic inequality decreased （GI 0.18）.According to our assessments,CAAs were enhanced,from the first to second stages,in terms of not only preventing premature mortality but also ameliorating health *** enhancements were related to increased sensitivity to the health effects of air pollution and synergic control of PM2.5and *** findings will contribute to optimizing future CAAs.

关键词： clean air action public health inequality fine particulate matter ozone

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Compact generation scheme of path–frequency hyperentangled photons using 2D periodical nonlinear photonic crystal

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Chinese Physics B 2023年第12期32卷 256-262页

作者：陈洋河季波李念芹姜震李维李昱东冯梁森武腾飞何广强 SJTU Pinghu Institute of Intelligent Optoelectronics Department of Electronic EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronic EngineeringShanghai Jiao Tong UniversityShanghai 200240China Science and Technology on Metrology and Calibration Laboratory Changcheng Institute of Metrology&MeasurementAviation Industry Corporation of ChinaBeijing 100095China

Hyperentanglement is a promising resource for achieving high capacity quantum ***,we propose a compact scheme for the generation of path-frequency hyperentangled photon pairs via spontaneous parametric down-conversion(SPDC)processes,where six different paths and two different frequencies are covered.A two-dimensional periodicalχ^((2))nonlinear photonic crystal(NPC)is designed to satisfy type-Ⅰquasi-phase-matching conditions in the plane perpendicular to the incident pump beam,and a perfect phase match is achieved along the pump beam's direction to ensure high conversion efficiency,with theoretically estimated photon flux up to 2.068×10^(5) pairs·s^(-1)·mm^(-2).We theoretically calculate the joint-spectral amplitude(JSA)of the generated photon pair and perform Schmidt decomposition on it,where the resulting entropy S of entanglement and effective Schmidt rank K reach 3.2789 and 6.4675,*** hyperentangled photon source scheme could provide new avenues for high-dimensional quantum communication and high-speed quantum information processing.

关键词： hyperentanglement nonlinear photonic crystal quasi-phase-matching

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simulation of pedestrian single-lane movement by a biped model

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Physical Review E 2018年第4期98卷 042309-042309页

作者： Zhongyi Huang Mohcine Chraibi Weiguo Song State key Laboratory of Fire Science University of Science and Technology of China Hefei 230027 China Institute for Advanced Simulation Forschungszentrum Jülich 52425 Jülich Germany

In most existing pedestrian dynamic models, agents are modeled as sliding or jumping objects. As a kind of bipedal creature, however, this assumption makes it difficult to include some important human walking characteristics in the models, such as the periodicity of stepping, the adjustment of step frequency and step length, and the change of personal space within the same step cycle. To take these characteristics into consideration, a “biped model” is developed to simulate pedestrian locomotion by physical step rather than by time step. The model consists of two components: the stepping simulator and the adjustment of velocity for each step. simulation results show that the velocity-density relations are consistent with the empirical data. Stable stop-and -go waves are simulated with a critical density. Furthermore, with the considering of biped movement, the lock-step phenomenon is reproduced. The model provides new possibilities to study crowd behavior while considering personal bipedal mechanics.

关键词： Transportation Collective dynamics Decision making models

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Research on key Technologies of Cross-domain Guidance 8

Research on Key Technologies of Cross-domain Guidance

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8th Symposium on Novel Photoelectronic Detection technology and Applications

作者： Guo, Xiaoyun Wu, Chengfeng Fang, Xueli Xu, Cheng Li, Hui Beijing Institute of Mechanical and Electrical Engineering Beijing China Beijing Institute of Mechanical and Electrical Engineering Science and Technology on Complex System Control and Intelligent Agent Cooperative Laboratory Beijing China Beijing Institute of Mechanical and Electrical Engineering Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (数字)9781510653122

ISBN: (纸本)9781510653115

Cross-domain synergy and intelligence will become important features of future warfare. Cross-domain guidance is one of the typical forms of cross-domain synergy. It can significantly improve the ability to respond quickly to random targets and time-sensitive targets and enhance the anti-jamming ability in the case of confrontation. This article introduces the concept and winning mechanism of cross-domain guidance, analyzes the research progress of cross-domain guidance at home and abroad, combs the key technologies of cross-domain guidance, summarizes the current challenges and problems in cross-domain guidance research, and proposes development suggestions. © 2022 SPIE

关键词： Optical engineering

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Hole-Mediated Lattice Oxygen Redox Design for Perovskite Oxide Catalysts

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Angewandte Chemie 2025年

作者： Dr. Xinbo Li Dr. Xiyang Wang Dr. Yaowen Wang Dr. Jingze Shao Prof. Yimin A. Wu Dr. Subhajit Jana Prof. Haozhe Liu Prof. Yue Peng Dr. Zhiyao Wu Dr. Zhen Li Dr. Yingge Cong Prof. Yawen Zhang Prof. Guangshe Li Prof. Liping Li State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 China Department of Mechanical and Mechatronics Engineering Waterloo Institute for Nanotechnology Materials Interface Foundry University of Waterloo Waterloo Ontario N2 L 3G1 Canada Center for High Pressure Science and Technology Advanced Research Beijing 100094 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi University Nanning 530004 China CAS Key Laboratory of Bio Medical Diagnostics Suzhou Institute of Biomedical Engineering and Technology Chinese Academy of Sciences Suzhou 215163 China Beijing National Laboratory for Molecular Sciences (BNLMS) State Key Laboratory of Rare Earth Materials Chemistry and Applications PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

Present design and application of perovskite oxide catalysts assume lattice oxygen redox (LOR) mechanisms that depend on lattice oxygen activity without consideration of the entire redox cycle. Herein, using in situ characterizations and theoretical calculations, we uncover a hole-mediated LOR cycle on p-type Sr-deficient SrFeO 3–δ (SFO-Srv) perovskites in CO oxidation reaction. Sr vacancies activate surface lattice oxygen of SFO-Srv and promote formation of highly covalent Fe (4–x)+ -O (2–x)– sites. In situ electrical conductivity measurement demonstrates that holes directly participate in the entire LOR cycle, and are reversibly consumed and regenerated in reducing/oxidizing atmosphere via Fe (4–x)+ -O (2–x)– sites of SFO-Srv. Hole-mediated LOR in SFO-Srv, as revealed by in situ soft X-ray absorption spectroscopy, occurs through changing in covalency of Fe−O bonds, O 2p hole state, and electron density of Fe sites. 18 O 2 labeling experiment further confirms an improved Mars–van Krevelen pathway in the hole-mediated LOR cycle, which accounts for a ten-times enhancement of SFO-Srv for CO reaction rate over that of SFO alone.

关键词： p-type perovskite oxides Sr vacancy lattice oxygen redox reaction mechanism SrFeO3

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Super-Resolution Stress Imaging for Terahertz-Elastic Based on SRCNN

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Optics and Photonics Journal 2022年第11期12卷 253-268页

作者： Delin Liu Zhen Zhen Yufen Du Ka Kang Haonan Zhao Chuanwei Li Zhiyong Wang Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Institute of Aeronautical Materials Beijing China Department of Mechanics Tianjin University Tianjin China

Limited by diffraction limit, low spatial resolution is one of the shortcomings of terahertz imaging. Low spatial resolution is also one of the reasons limiting the development of stress measurement using terahertz imaging. In this paper, the full-field stress measurement using Terahertz Time Domain Spectroscopy (THz-TDS) is combined with Super-Resolution Convolutional Neural Network (SRCNN) algorithm to obtain stress fields with high spatial resolution. A modulation model from a plane stress state to a THz-TDS signal is constructed. A large number of simulated sets are obtained to train the SRCNN model. By applying the trained SRCNN model to imaging the numerical and physical stress fields, the improved spatial resolution of stress field calculated from the captured THz-TDS signal is obtained.

关键词： THz-TDS Stress Measurement Super-Resolution Convolutional Neural Network

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