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Large-scale model test study on the water pressure resistance of construction joints of karst tunnel linings

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Frontiers of Structural and Civil Engineering 2023年第8期17卷 1249-1263页

作者： meng huang Mingli huang Ze YANG Yuan SONG Zhien ZHANG School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China Enterprise Key Laboratory Tianjin Municipal Engineering Design and Research InstituteTianjin 300392China School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China

Model tests and numerical calculations were adopted based on the New Yuanliangshan tunnel project to investigate the water pressure resistance of lining construction joints in high-pressure and water-rich karst tunnels.A large-scale model test was designed and conducted,innovatively transforming the external water pressure of the lining construction joint into internal water *** effects of the embedded position and waterstop type on the water pressure resistance of the construction joint were analyzed,and the reliability of the model test was verified via numerical *** results show that using waterstops can significantly improve the water pressure resistance of lining construction *** water pressure resistance of the lining construction joint is positively correlated with the lining thickness and embedded depth of the *** addition,the type of waterstop significantly influences the water pressure resistance of lining construction *** test results show that the water pressure resistance of the embedded transverse reinforced waterstop is similar to that of the steel plate waterstop,and both have more advantages than the rubber *** water pressure resistance of the construction joint determined via numerical calculations is similar to the model test results,indicating that the model test results have high accuracy and *** study provides a reference for similar projects and has wide applications.

关键词： karst tunnel lining construction joint water pressure resistance large-scale model test numerical calculations

Achieving Paris Agreement temperature goals requires carbon neutrality by middle century with far-reaching transitions in the whole society

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Advances in Climate Change Research 2021年第2期12卷 281-286页

作者： huang meng-Tian ZHAI Pan-Mao State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing100081China

The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris *** keep these goals within reach,peaking the global carbon emissions as soon as possible andachieving carbon neutrality are urgently ***,global CO_(2)emissions continued to grow up to a record high of 43.1 Gt CO_(2)during2019,with fossil CO_(2)emissions of 36.5 Gt CO_(2)and land-use change emissions of 6.6 Gt CO_(2).In such case,the global carbon emissions mustdrop 32 Gt CO_(2)(7.6%per year)from 2020 to 2030 for the 1.5C warming limit,which is even larger than the COVID-induced reduction(6.4%)in global CO_(2)emissions during ***,China has announced scaling up its national commitments,aiming to peak its CO_(2)emissionsbefore 2030 and achieve carbon neutrality before *** these goals requires rapid and far-reaching transitions in the whole *** one hand,deeper emissions reduction in all sectors includes decarbonization of energy,electrification,increasing share of renewables,energyefficiency,sustainable land management,decarbonization of transport,reducing food loss and waste,as well as behavior and lifestyles *** the other hand,possible actions by removing CO_(2)from the atmosphere involves enlarging land and ocean net carbon sink,CO_(2)removaltechnologies(such as Bioenergy with carbon capture and storage),and CO_(2)capture,utilization and storage technologies,but should be cautionfor their scales and tradeoffs.

关键词： Carbon neutrality Carbon emissions peak Climate change Paris agreement Green recovery COVID-19 pandemic

Analyticity of the Sine Family with L^P-Maximal Regularity for Second Order Cauchy Problems

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Acta Mathematica Sinica,English Series 2010年第3期26卷 561-568页

作者： Yong Zhong huang meng Cheng WANG School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 P. R. China

If the second order problem u（t）＋ Bu（t）＋ Au（t） = f（t）, u（0） =u（0） = 0 has L^p-maximal regularity, 1 〈 p 〈 ∞, the analyticity of the corresponding propagator of the sine type is shown by obtaining the estimates of ‖λ（λ^2 ＋ λB ＋ A）^-1‖ and ‖B（λ^2 ＋ λB ＋ A）^-1‖ for λ∈ C with Reλ 〉 ω, where the constant ω≥ 0.

关键词： analyticity second order Cauchy problem maximal regularity propagator

Desertification dynamics in China's drylands under climate changeAuthor links open overlay panel

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Advances in Climate Change Research 2023年第3期14卷 429-436页

作者： meng-Tian huang Pan-Mao ZHAI State Key Laboratory of Severe Weather and Institute of Global Change and Polar Meteorology Chinese Academy of Meteorological SciencesBeijing 100081China

Much of drylands has been hit by land degradation during the recent *** whether and how desertification is related to climate change is poorly ***,using the Normalized Difference Vegetation Index(NDVI)time series and climatic variables,we assessed the desertification dynamics over China's drylands from 1982 to 2016 and explored the climate change impacts,with a particular focus on the influence of the 2015/2016 El Niño *** found a fluctuant downward trend of barren land area from 1982 to the early 2010s,but followed by a sharp increase *** in precipitation combined with high temperature are major contributors to the barren land *** the 2015/2016 El Niño,the concurrence of severe drought and heat stress gave rise to the most serious land desertification in the ***-arid and arid drylands are the predominant contributors to the abrupt barren land area increase during 2015/*** findings,therefore,highlight the climate change impacts on dryland desertification *** dryland expansion and accompanying drought stress may exacerbate the risk of land degradation in these regions.

关键词： Desertification Dryland ecosystems Climate change El nino China

Modeling method of sequence admittance for three-phase voltage source converter under unbalanced grid condition

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Journal of Modern Power Systems and Clean Energy 2018年第3期6卷 595-606页

作者： Yang CEN meng huang Xiaoming ZHA School of Electrical Engineering Wuhan University

The admittance is a strong tool for stability analysis and assessment of the three-phase voltage source converters(VSCs) especially in grid-connected ***, the sequence admittance is hard to calculate when the VSC is operating under unbalanced grid voltage conditions. In this paper, a simple and direct modeling method is proposed for a three-phase VSC taking the unbalanced grid voltage as a new variable for the *** coupling in the three-phase system can be calculated by applying the harmonic linearization method. The calculated admittance of three-phase VSCs is verified by detailed circuit simulations.

关键词： Unbalanced grid voltage Three-phase voltage source converter Harmonic linearization Positive and negative sequence admittance Stability

A Study on Enhancing Chip Detection Efficiency Using the Lightweight Van-YOLOv8 Network

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Computers, Materials & Continua 2024年第4期79卷 531-547页

作者： meng huang Honglei Wei Xianyi Zhai School of Mechanical Engineering and Automation Dalian Polytechnic UniversityDalian116034China

In pursuit of cost-effective manufacturing,enterprises are increasingly adopting the practice of utilizing recycled semiconductor *** ensure consistent chip orientation during packaging,a circular marker on the front side is employed for pin alignment following successful functional ***,recycled chips often exhibit substantial surface wear,and the identification of the relatively small marker proves ***,the complexity of generic target detection algorithms hampers seamless *** these issues,this paper introduces a lightweight YOLOv8s-based network tailored for detecting markings on recycled chips,termed ***,to alleviate the influence of diminutive,low-resolution markings on the precision of deep learning models,we utilize an upscaling approach for enhanced *** technique relies on the Super-Resolution Generative Adversarial Network with Extended Training(SRGANext)network,facilitating the reconstruction of high-fidelity images that align with input ***,we replace the original YOLOv8smodel’s backbone feature extraction network with the lightweight VanillaNetwork(VanillaNet),simplifying the branch structure to reduce network ***,a Hybrid Attention Mechanism(HAM)is implemented to capture essential details from input images,improving feature representation while concurrently expediting model inference *** results demonstrate that the Van-YOLOv8 network outperforms the original YOLOv8s on a recycled chip dataset in various ***,it demonstrates superiority in parameter count,computational intricacy,precision in identifying targets,and speed when compared to certain prevalent algorithms in the current *** proposed approach proves promising for real-time detection of recycled chips in practical factory settings.

关键词： Lightweight neural networks attention mechanisms image super-resolution enhancement feature extraction small object detection

Metal–air batteries: A review on current status and future applications

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Progress in Natural Science:Materials International 2023年第2期33卷 151-171页

作者： Tao Li meng huang Xue Bai Yan-Xiang Wang Key Laboratory of Liquid-Solid Structural Evolution and Processing of Materials of Ministry of Education Shandong University School of Materials Science and Engineering Shandong University of Science and Technology

Metal–air batteries(MABs) have been paid much more attention owing to their greater energy density than the most advanced lithium-ion batteries(LIBs). Rechargeable MABs are considered as promising candidates for the next-generation of energy storage techniques for applications ranging from large-scale energy storage systems to electric vehicles and portable devices. However, there are still numerous scientific problems that must be overcome before their commercial application. With the aim of providing a comprehensive understanding of this new electrochemical system particularly Li–air batteries, this review paper provides an overview of the current status including corresponding strategies from the perspective of various battery components, including air cathode,metal anode and electrolyte. In addition, other promising MABs such as Zn–air, Mg–air and Al–air batteries are also introduced briefly for comparison. Finally, the applications and prospects of these four types of MABs are discussed and some perspectives for this research field are also provided.

关键词： Metal–air batteries Air cathode Metal anode Electrocatalyst Electrolyte

Study of spatial resolution of the associated alpha particle imaging–time-of-flight method

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Nuclear Science and Techniques 2019年第4期30卷 105-113页

作者： meng huang Jian-Yu Zhu Jun Wu Center for Strategic Studies China Academy of Engineering Physics

Associated alpha particle imaging based on the time-of-flight(API-TOF) technique is an advanced neutron analysis method, which is capable of discriminating material nuclides and three-dimensional imaging of the spatial distribution of material nuclei. In this paper, the spatial resolution of API-TOF and its effects are studied using mathematical analysis and Monte Carlo numerical simulation. The results can provide guidance and assist in designing of API-TOF detection devices. First, a mathematical analysis of the imaging principles of the API-TOF was carried out, and the calculation formulas of the spatial resolution of API-TOF were deduced. Next, the relationship between the device layout and the spatial resolution of the API-TOF detection device was studied. The concept of a typical API-TOF detection device with an optimized structure was proposed. Then, the spatial distribution of the spatial resolution of the typical API-TOF detection device was analyzed, and the effects of the time resolution and the neutron emission angle resolution on the spatial resolution were studied. The results show that spatial resolutions better than 1 cm can be achieved by improving the time resolution and the neutron emission angle resolution to appropriate levels. Finally, a Monte Carlo numerical simulation program was developed for the study of the APITOF and was used to calculate the spatial resolutions of the API-TOF. The comparison of the results shows that thespatial resolutions calculated based on the Monte Carlo numerical simulation are in good agreement with those calculated based on the mathematical analysis. This verifies the mathematical analysis and the evaluation of the effects of the spatial resolution of the API-TOF in this study.

关键词： API-TOF Spatial resolution Mathematical analysis Monte Carlo numerical simulation

EMBEDDINGS OF ONE KIND OF GRAPHS

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Applied Mathematics(A Journal of Chinese Universities) 1997年第3期12卷 253-258页

作者： meng JIXIANG AND huang QIONGXIANG Department of Mathematics Northern Jiatong University Beijing

In this paper, Hamiltonian cycles and decompositions of Cayley digraphs are investigated. Sufficient conditions are given for these two problems respectively. Furthermore, the conditions are also necessary for 2 regular Cayley digraphs. In addition, some known results about the Cartesian products of two directed cycles are also deduced.

关键词： Surface embedding graph