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Experimental study on permeability of spun high strength concrete material during mechanical loading

CONSTRUCTION AND BUILDING MATERIALS 2023年第1期403卷

作者： He, Jingran Hong, Junjie Gao, Ruofan Liu, Feng Li, Lijuan Guangdong Univ Technol Univ Mega Ctr Sch Civil & Transportat Engn 100 Waihuan West Rd Guangzhou 510006 Peoples R China Jinan Univ Sch Mech & Construct Engn 601 West Huangpu Ave Guangzhou 510632 Peoples R China Minist Educ China Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Workstat Xuwen Cty Guangdong Hydropower Energy Co 207 Natl Highway Xuwen 524100 Guangdong Peoples R China

The pretensioned spun high strength concrete pipe pile (PHC pipe pile) is widely applied in important infrastructures of off-shore zones due to its low permeability and high capacity. During the construction process and the whole service period of PHC pipe piles, the damage is inevitably caused by many reasons, which may eventually cause the early durability failure of piles. Many researches have been conducted to study the change in permeability of normal concrete due to mechanical damage. However, the relation between permeability and damage of spun high strength concrete (SHSC) is still not been studied. To quantitively investigate the change of permeability of SHSC, a series of specimens of PHC pipe piles were tested for the change of permeability during mechanical loading process in this study. As a result, the relation of stress and permeability of spun high strength concrete as well as the crack roughness of the SHSC is obtained for efficient application in engineering. Before the 40% stress ratio, the permeability of the SHSC is slightly decreased as the compressive stress increases. The mean value and standard deviation of the intrinsic permeability of the SHSC are increased as the compressive stress loading reaches the peak stress. The order of magnitude of the crack roughness & xi;can be taken as 10 -4 for engineering application. Compared with the vibrate-casted concrete, the crack roughness & xi;is smaller, indicating that the crack surface of SHSC is rougher than the vibrate-casted concrete.

关键词： Spun high strength concrete Permeability Coupling of permeability and stress Poiseuille 's law

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Strengthening Influence of El Nino on the Following Spring Precipitation over the Indochina Peninsula

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JOURNAL OF CLIMATE 2021年第14期34卷 5971-5984页

作者： Li, Gen Gao, Chujie Xu, Bei Lu, Bo Chen, Haishan Ma, Hedi Li, Xing Hohai Univ Coll Oceanog Nanjing Peoples R China Southern Marine Sci & Engn Guangdong Lab Zhuhai Zhuhai Peoples R China Chinese Acad Sci South China Sea Inst Oceanol State Key Lab Trop Oceanog Guangzhou Peoples R China Jinling Inst Technol Coll Intelligent Sci & Control Engn Nanjing Peoples R China Chinese Acad Sci Inst Earth Environm State Key Lab Loess & Quaternary Geol Xian Peoples R China China Meteorol Adm Lab Climate Studies & CMA NJU Joint Lab Climate P Natl Climate Ctr Beijing Peoples R China Nanjing Univ Informat Sci & Technol Key Lab Meteorol Disaster Minist Educ Nanjing Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Nanjing Peoples R China China Meteorol Adm Hubei Key Lab Heavy Rain Monitoring & Warning Res Inst Heavy Rain Wuhan Peoples R China Chengdu Univ Informat Technol Coll Atmospher Sci Plateau Atmosphere & Environm Key Lab Sichuan Pro Chengdu Peoples R China

Significance Statement Spring precipitation variation has profound economic and societal influences for the Indochina Peninsula (ICP) that consists of several agriculture-based countries. Moreover, the local soil moisture anomaly induced by the ICP spring precipitation is an important seasonal predictor for the East Asian summer monsoon and extreme climate. Here this study identifies a strengthening influence of El Nino on the following spring precipitation over the ICP, due to a relatively stronger intensity and longer duration of the El Nino-related warm SST anomalies over the tropical central Pacific since the early 1990s. This may provide an important implication for the seasonal predictions of summer monsoon and extreme climate over East Asia and thus potentially enhance the predictability of regional climate. El Nino is a dominant source of interannual climate variability around the world. Based on the observed and reanalyzed datasets for the period of 1958-2019, this study explores the influence of El Nino on the spring precipitation over the Indochina Peninsula (ICP). The results show that El Nino has a significant negative correlation with the following spring precipitation over the ICP. However, this climatic teleconnection of El Nino was unstable, with an obvious interdecadal strengthening since the early 1990s. During the decaying spring, the El Nino-related sea surface temperature (SST) anomalies would induce an abnormal downward motion along with an anomalous low-level anticyclone over the western North Pacific. Before the early 1990s, such El Nino-induced atmospheric circulation anomalies were located to the east of the ICP, exerting little influence on the spring ICP precipitation. In contrast, since the early 1990s, the abnormal downward motion and anomalous low-level anticyclone extended westward covering the whole ICP, hampering local spring precipitation. This interdecadal change is owing to a relatively stronger intensity and longer duration of

关键词： Precipitation Atmosphere-ocean interaction Climate variability El Nino Interannual variability

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UAV-Aided Secure Communication With Deployment Optimization and Cooperative Jamming 11

UAV-Aided Secure Communication With Deployment Optimization ...

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11th International Conference on Intelligent control and Information Processing, ICICIP 2021

作者： Li, Hongbing Wu, Juan Luo, Lei Xiong, Jiang Chongqing Three Gorges University Key Lab. of Intelligent Information Processing and Control of Chongqing Municipal Institutions Chongqing Engineering Research Center of Internet of Things and Intelligent Control Technology Wanzhou China Chongqing Three Gorges University Chongqing Key Laboratory of Geological Environment Monitoring and Disaster Early-Warning Wanzhou China Beijing University of Posts and Telecommunications School of Artificial Intelligence Beijing China

ISBN: (纸本)9781665425155

This paper investigates the jointly transmit power and unmanned aerial vehicle (UAV)/jammer deployment optimization problem for UAV enabled jammer-assisted secure communication systems, where a jammer is exploited to assist transmitting data from a source node to a legitimate destination node in the presence of multiple eavesdroppers. To increase the secrecy energy efficiency, which is defined as the achievable secrecy rate per energy consumption unit, we formulate a secrecy energy efficiency maximization problem by jointly optimizing the transmit power and UAV/jammer deployment. The resulting optimization problem is shown to be a non-convex and fractional optimization problem, which is challenging to solve. As such, we decompose the original problem into two sub-problems, and then, an efficient iterative algorithm is proposed by leveraging the extensive search method and Dinkelbach method in combination with successive convex approximation (SCA) techniques. Numerical simulation results show that the proposed scheme significantly improves the secrecy energy efficiency of the system. © 2021 IEEE.

关键词： Energy efficiency

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Artificial intelligence for geoscience:Progress,challenges,and perspectives

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The Innovation 2024年第5期5卷 136-160,135页

作者： Tianjie Zhao Sheng Wang Chaojun Ouyang Min Chen Chenying Liu Jin Zhang Long Yu Fei Wang Yong Xie Jun Li Fang Wang Sabine Grunwald Bryan MWong Fan Zhang Zhen Qian Yongjun Xu Chengqing Yu Wei Han Tao Sun Zezhi Shao Tangwen Qian Zhao Chen Jiangyuan Zeng Huai Zhang Husi Letu Bing Zhang Li Wang Lei Luo Chong Shi Hongjun Su Hongsheng Zhang Shuai Yin Ni Huang Wei Zhao Nan Li Chaolei Zheng Yang Zhou Changping Huang Defeng Feng Qingsong Xu Yan Wu Danfeng Hong Zhenyu Wang Yinyi Lin Tangtang Zhang Prashant Kumar Antonio Plaza Jocelyn Chanussot Jiabao Zhang Jiancheng Shi Lizhe Wang Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Computer Science China University of GeosciencesWuhan 430078China State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Key Laboratory of Virtual Geographic Environment(Ministry of Education of PRC) Nanjing Normal UniversityNanjing 210023China Data Science in Earth Observation Technical University of Munich80333 MunichGermany The National Key Laboratory of Water Disaster Prevention Yangtze Institute for Conservation and DevelopmentHohai UniversityNanjing 210098China Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Soil Water and Ecosystem Sciences DepartmentUniversity of FloridaPO Box 110290GainesvilleFLUSA Materials Science Engineering Program Cooperating Faculty Member in the Department of Chemistry and Department of Physics Astronomy University of CaliforniaCaliforniaRiversideCA 92521USA Institute of Remote Sensing and Geographical Information System School of Earth and Space SciencesPeking UniversityBeijing 100871China Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China College of Geography and Remote Sensing Hohai UniversityNanjing 211100China Department of Geography The University of Hong KongHong Kong 999077SARChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing 210044China School of Environmental Science and Engineering Nanjing University of Information Science&TechnologyNanjing 210044China Collaborative Inno

This paper explores the evolution of geoscientific inquiry,tracing the progression from traditional physics-based models to modern data-driven approaches facilitated by significant advancements in artificial intelligence(AI)and data collection *** models,which are grounded in physical and numerical frameworks,provide robust explanations by explicitly reconstructing underlying physical ***,their limitations in comprehensively capturing Earth’s complexities and uncertainties pose challenges in optimization and real-world *** contrast,contemporary data-driven models,particularly those utilizing machine learning(ML)and deep learning(DL),leverage extensive geoscience data to glean insights without requiring exhaustive theoretical *** techniques have shown promise in addressing Earth science-related ***,challenges such as data scarcity,computational demands,data privacy concerns,and the“black-box”nature of AI models hinder their seamless integration into *** integration of physics-based and data-driven methodologies into hybrid models presents an alternative *** models,which incorporate domain knowledge to guide AI methodologies,demonstrate enhanced efficiency and performance with reduced training data *** review provides a comprehensive overview of geoscientific research paradigms,emphasizing untapped opportunities at the intersection of advanced AI techniques and *** examines major methodologies,showcases advances in large-scale models,and discusses the challenges and prospects that will shape the future landscape of AI in *** paper outlines a dynamic field ripe with possibilities,poised to unlock new understandings of Earth’s complexities and further advance geoscience exploration.

关键词： Earth utilizing landscape

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Ultimate strength analysis of local thinning tee pipe considering plastic strengthening effect

Ultimate strength analysis of local thinning tee pipe consid...

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2020 International Conference on Applied Physics and Computing, ICAPC 2020

作者： Su, Wei Luo, Wenhao Dong, Xianshan Liu, Renhuai MOE Key lab of Disaster Forecast and Control in Engineering Guangzhou 510632 China Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory China Electronic Product Reliability Environmental Testing Research Institute Guangzhou510610 China School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China

In this paper, the locally thinned three-way structure under internal pressure is analyzed based on the theory of plastic strengthening effect and limit analysis. A finite element model is presented through ANSYS commercial software to simulate the mechanical properties of orthogonal and oblique three-way structures. This paper systematically analyses how the shape and size of the thinning effect the plastic limit load of the pipe and what is the typical failure mode of plastic failure. Some valuable conclusions are drawn, which provide a useful reference for the design and production of the tee pipe. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Finite element method

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Design and simulation of ultra-thin and high-efficiency silicon-based trichromatic PIN photodiode arrays for visible light communication

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OPTICS COMMUNICATIONS 2020年 475卷 126296-126296页

作者： Gao, Dan Zhang, Jun Wang, Fan Liang, Jingqiu Wang, Weibiao Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Guangzhou 510632 Peoples R China Jinan Univ Dept Optoelect Engn Guangzhou 510632 Peoples R China Jinan Univ Guangdong Prov Key Lab Opt Fiber Sensing & Commun Guangzhou 510632 Peoples R China Jinan Univ Key Lab Optoelect Informat & Sensing Technol Guan Guangzhou 510632 Peoples R China Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys State Key Lab Appl Opt Changchun 130033 Jilin Peoples R China

Visible light communication offers abundant spectrum resources, which can alleviate the current shortage of wireless communication spectrum resources, and the security of the system is very reliable. In this study, a new photodiode (PD) array with micro-nano optical structure is designed and shown to effectively improve the absorption efficiency of PDs to blue, green, and red light. The absorption efficiency of blue, green, and red light at the central wavelength reached 96.8%, 97.5% and 98.6%, respectively, thus demonstrating the improved quantum efficiency of the device. Moreover, three color PDs are integrated into an ultra-thin silicon-on-insulator structure, increasing the integration and response speed of the device. The ultra-thin structure of the PD increases the response bandwidth up to the GHz level.

关键词： Array Photodiode Subwavelength structure Nanostructure

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Bistable Nonlinear Energy Sink Using Magnets and Linear Springs: Application to Structural Seismic control

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SHOCK AND VIBRATION 2021年第1期2021卷

作者： Chen, Y. Y. Zhao, W. Shen, C. Y. Qian, Z. C. Guangzhou Univ MOE Key Lab Earthquake Resistance Earthquake Miti Earthquake Engn Res & Test Ctr Guangzhou 510405 Peoples R China Guangzhou Univ Guangdong Prov Key Lab Earthquake Engn & Appl Tec Guangzhou 510405 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Guangzhou 510632 Peoples R China

Nonlinear energy sink (NES) has proven to be very effective in reducing the vibration response of structures. In this paper, a magnetic bistable nonlinear energy sink (BNES) that composed of a guided moving mass attached with linear springs and permanent magnets is proposed. To assess the seismic control performance of the proposed BNES, a shear frame model equipped with the proposed BNES is compared with the same shear frame model equipped with an optimized cubic NES and with a linear tuned mass damper (TMD) system. The results show that, in the idealized situation, where the mass and stiffness is clearly defined (no uncertainty), the BNES can achieve similar performance as a thoroughly in-tuned TMD system. Moreover, in the detuned condition, due to broadband high internal resonance capability, the proposed BNES can outperform the linear TMD and the cubic NES. The study demonstrates that the proposed BNES can be used as an efficient passive vibration absorber for structural seismic control.

关键词： Seismology

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Ultimate strength analysis of three-way pipe considering plastic reinforcement effect

Ultimate strength analysis of three-way pipe considering pla...

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2020 International Conference on Applied Physics and Computing, ICAPC 2020

Considering the plastic reinforcement effect in materials, the plastic limit load of the three-way structure is analyzed. ANSYS commercial finite element software is used for numerical simulation. According to the results, the paper discusses the influence of the plastic reinforcement effect on the pipe's plastic ultimate load and failure mode. And the structure is further analyzed to verify the theory and design ideas in actual engineering. For improving the design and safety assessment of the three-way structure, the results provide a theoretical basis and a numerical reference, and the finite element method is economical than the experimental method. At last, it satisfies the accuracy requirements of engineering. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Finite element method

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Wave soldering structure optimization simulation of multilayer ceramic capacitors

Wave soldering structure optimization simulation of multilay...

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2020 International Conference on Applied Physics and Computing, ICAPC 2020

作者： Su, Wei Luo, Wenhao Li, Junkui Liu, Renhuai MOE Key lab of Disaster Forecast and Control in Engineering Guangzhou510632 China Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou510610 China School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China

In this paper, the thermal analysis and structural analysis of MLCC are carried out by using the commercial finite element software ANSYS. By comparing the thermal-mechanical analysis results of the structural optimization models of different schemes, the optimal optimization scheme is found. The model calculated the time required for MLCC to reach temperature stability considering thermal convection and heat conduction, and obtained the thermal deformation and thermal stress distribution of MLCC element. Based on the analysis results of MLCC original model, the thermal analysis under different wave soldering temperatures was carried out. Based on the simulated transient results, the structure and materials of MLCC key components were optimized. The results provide a basis for the optimal design of MLCC. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Thermoanalysis

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Structural damage detection using relationship between transmissibility functions and stiffness variations 9

Structural damage detection using relationship between trans...

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9th International Conference on Structural Health Monitoring of Intelligent Infrastructure: Transferring Research into Practice, SHMII 2019

作者： Liu, H.L. Chen, Z.P. Yu, L. School of Mechanics and Construction Engineering Jinan University Guangzhou China Moe Key Lab of Disaster Forecast and Control in Engineering Jinan University Guangzhou China

Structural damage detection (SDD), as one of the most challenging issues in the field of structural health monitoring (SHM), has been extensively studied in recent years. A lot of methodologies have been proposed for effective SDD. However, in most cases, only structural responses, e.g. accelerations, can be easily measured in practical engineering, which limits the application of numerous SDD algorithms. In this study, a novel SDD method is proposed for damage localization and quantification by means of a newly deduced relationship between transmissibility functions (TFs) and stiffness variations. First, a finite element (FE) model is developed for a real structure, and only stiffness variations are esteemed when structural damages occur in the structure. As a ratio between frequency response functions of structural responses, the TFs are used to detect damages by using structural responses only. Moreover, as prior information, the sparsity of structural damages is introduced and the sparse regularization is employed to improve the reasonability of SDD results. Finally, numerical simulations on damages in a simply-supported beam are conducted to assess the performance of the proposed SDD method. The illustrated SDD results show that the proposed method can effectively locate structural damages and quantify damage severities with a good robustness to measurement noises. Copyright © SHMII 2019. All rights reserved.

关键词： Structural health monitoring

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