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Theoretical research on gas seepage in the formations surrounding bedded gas storage salt cavern

Petroleum Science 2022年第4期19卷 1766-1778页

作者： xiang-sheng chen Yin-Ping Li Ya-Long Jiang Yuan-Xi Liu Tao Zhang State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013Jiangxi China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071 HubeiChina University of Chinese Academy of Sciences Beijing 100049China

When constructing salt cavern gas or petroleum storage in lacustrine sedimentary salt formations rich in mudstone interlayers, the influence of the sealing performance of interlayers and salt-mud interface on the storage tightness should be considered adequately. In order to reveal the gas seepage in deep formations surrounding bedded salt cavern underground storage, a leakage analysis model was established based on the characteristics of a low dip angle and the interbedded structure of bedded rock salt. The gas seepage governing equations for one-dimensional and plane radial flow were derived and solved. A gas seepage simulation experiment was conducted to demonstrate the accuracy and reliability of the theoretical calculation results. The error of the seepage range was approximately 6.70%, which is acceptable. The analysis and calculation results indicate that the motion equation of gas in deep formations satisfies a non-Darcy's law with a threshold pressure gradient and slippage effect. The sufficient condition for the gas flow to stop is that the pressure gradient is equal to the threshold pressure *** relationship between the leakage range and operating time is a positive power function, that is, the leakage range gradually increases with time and eventually stabilizes. As the seepage range increases, the seepage pressure decreases sharply during the early stage, and then decreases gradually until the flow *** the research results with engineering applications, three quantitative evaluation indexes named the maximum admissible leakage range, leakage volume and leakage rate are proposed for the tightness evaluation of gas storage salt cavern during their operating stage. These indexes can be used directly in actual engineering applications and can be compared with the key design parameters stipulated in the relevant specifications. This work is expected to provide theoretical and technical support for the gas loss and tightness evaluation of

关键词： Gas storage salt cavern Seepage Tightness Non-Darcy's law Leakage

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Prediction of ground settlements induced by twin shield tunnelling in rock and soil--A case study

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Underground Space 2022年第4期7卷 623-635页

作者： Xue-tao Wang Thomas von Schmettow xiang-sheng chen Chang-qing Xia College of Civil and Transportation Engineering Shenzhen University518060 ShenzhenChina Underground Polis Academy Shenzhen University518060 ShenzhenChina Key Laboratory of Coastal Urban Resilient Infrastructures(MOE) Shenzhen University518060 ShenzhenChina Tunnels Engineering Zentrale TechnikEd.Zu¨blinStuttgart 70567Germany

Ground movements caused by the construction of tunnels and excavation are *** of such movements is a very important for risk management in tunnel *** paper presents a case study of ground settlements induced by twin shield tunnelling in Copenhagen using analytical and numerical methods and their *** predictions are compared with the monitored *** comparison shows that the predictions are sufficiently conservative.

关键词： Shield tunneling Greenfield settlement Empirical method Analytical method FEM

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Two-Layer Attention Feature Pyramid Network for Small Object Detection

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Computer Modeling in Engineering & Sciences 2024年第10期141卷 713-731页

作者： sheng xiang Junhao Ma Qunli Shang Xianbao Wang Defu chen College of Information Engineering Zhejiang University of TechnologyHangzhou310023China Binjiang Cyberspace Security Institute of ZJUT Hangzhou310056China

Effective small object detection is crucial in various applications including urban intelligent transportation and pedestrian ***,small objects are difficult to detect accurately because they contain less *** current methods,particularly those based on Feature Pyramid Network(FPN),address this challenge by leveraging multi-scale feature ***,existing FPN-based methods often suffer from inadequate feature fusion due to varying resolutions across different layers,leading to suboptimal small object *** address this problem,we propose the Two-layerAttention Feature Pyramid Network(TA-FPN),featuring two key modules:the Two-layer Attention Module(TAM)and the Small Object Detail Enhancement Module(SODEM).TAM uses the attention module to make the network more focused on the semantic information of the object and fuse it to the lower layer,so that each layer contains similar semantic information,to alleviate the problem of small object information being submerged due to semantic gaps between different *** the same time,SODEM is introduced to strengthen the local features of the object,suppress background noise,enhance the information details of the small object,and fuse the enhanced features to other feature layers to ensure that each layer is rich in small object information,to improve small object detection *** extensive experiments on challenging datasets such as Microsoft Common Objects inContext(MSCOCO)and Pattern Analysis Statistical Modelling and Computational Learning,Visual Object Classes(PASCAL VOC)demonstrate the validity of the *** results show a significant improvement in small object detection accuracy compared to state-of-theart detectors.

关键词： Small object detection two-layer attention module small object detail enhancement module feature pyramid network

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Response characteristics of PWR primary circuit under SBLOCAs considering steam bypass discharging

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Nuclear Science and Techniques 2024年第6期35卷 189-201页

作者： Shuai Yang xiang-Bin Li Yu-sheng Liu Jia-Ning Xu De-chen Zhang School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy Beijing 102206China Nuclear and Radiation Safety Center MEPBeijing 100084China

Small-break superposed station blackout(SBO)accidents are the basic design accidents of nuclear power *** the condition of a small break in the cold leg,SBO further increases the severity of the accident,and the steam bypass discharg-ing system(GCT)in the second circuit can play an important role in guaranteeing core *** explore the influence of the GCT on the thermal-hydraulic characteristics of the primary circuit,RELAP5 software was used to establish a numerical model based on a typical pressurized water reactor nuclear power *** different small breaks in the cold-leg super-posed SBO were selected,and the impact of the GCT operation on the transient response characteristics of the primary and secondary circuit systems was *** results show that the GCT plays an indispensable role in core heat removal during an accident;otherwise,core safety cannot be *** GCT was used in conjunction with the primary safety injection system during the placement *** the break diameter was greater than a certain critical value,the core cooling rate could not be guaranteed to be less than 100 K/h;however,the core remained in a safe state.

关键词： Steam bypass discharging Pressurized water reactor SBLOCA Numerical simulation

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Leprosy Update in China, 2019

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International Journal of Dermatology and Venereology 2022年第1期5卷 15-19页

作者： Le Wang Pei-Wen Sun Mei-Wen Yu Heng Gu Hong-sheng Wang xiang-sheng chen National Center for Leprosy Control Chinese Center for Disease Control and PreventionHospital for Skin Diseases(Institute of Dermatology)Chinese Academy of Medical Sciences and Peking Union Medical CollegeNanjingJiangsu 210042China

Objective:To study the epidemiology of leprosy in China in 2019 and give suggestions to improve future leprosy control ***:We collected leprosy data from the Leprosy Management Information System in China,which includes data from 31 Chinese provinces,autonomous regions,and municipalities,except for Hong Kong,Macao,and *** then performed a descriptive analysis of these ***:A total of 464 new leprosy cases were reported nationwide in 2019,with a case detection rate of 0.033/100,*** proportions of children younger than 15 years,multibacillary cases,and cases with World Health Organization grade 2 disability were 1.3%,90.3%,and 21.6%,respectively.A total of 2,219 leprosy cases were registered in China by the end of 2019,giving a prevalence rate of 0.158/100,***-six counties had a prevalence rate of more than 1/100,000,and most of them were located in Southwest *** were 31 reported relapse ***:The prevalence of leprosy has improved continuously throughout China,but the southwest region is still an area of concern.

关键词： 2019 China epidemiology leprosy

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Anchoring heterometallic cluster on P-doped carbon nitride for efficient photocatalytic nitrogen fixation in water and air ambient

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Chinese Chemical Letters 2024年第4期35卷 176-180页

作者： Chao-Long chen Rong chen La-sheng Long Lan-Sun Zheng xiang-Jian Kong Collaborative Innovation Center of Chemistry for Energy Materials State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Light-driven nitrogen fixation to produce ammonia is a green and economical technology of nitrogen reduction but is still quite challenging, especially in an air atmosphere without any sacrificial ***, we demonstrate efficient photocatalytic nitrogen fixation using water and air directly by loading lanthanide–transition metal(4f–3d) cluster NdCo_(3) on two-dimensional P-doped graphitic carbon nitrides(PCN) material surface. Benefiting from the increase in the number of nitrogen vacancies(NVs) and highly matched band gap structure and excellent hole trapping ability of clusters, the NdCo_(3)/PCN photocatalyst exhibits efficient nitrogen reduction activity with 371(in air) and 825 μmol h^(-1)g^(-1)(in pure nitrogen)without any sacrificial reagents. The introduction of potassium sulfate inhibits hydrogen production and promotes nitrogen reduction activation. This work suggests that anchoring precisely structured clusters on 2D materials may enhance photocatalytic nitrogen reduction under normal temperature and pressure.

关键词： Photocatalytic Nitrogen fixation 4f-3d Cluster Air atmosphere

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One-step calcination synthesis of interface-coherent crystallized and surface-passivated LiNi_(0.5)Mn_(1.5)O_(4) for high-voltage lithium-ion battery

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Nano Research 2024年第5期17卷 4192-4202页

作者： Min Xu Bifu sheng Yong cheng Junjie Lu Minfeng chen Peng Wang Bo Liu Jizhang chen xiang Han Ming-sheng Wang Siqi Shi College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry UniversityNanjing 210037China State Key Laboratory of Physical Chemistry of Solid Surfaces College of MaterialsXiamen UniversityXiamen 361005China College of Mathematics and Physics Jinggangshan UniversityJi’an 343009China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Western Digital Corporation 951 Sandisk DrMilpitasCA 95035USA

LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)with a spinel crystal structure presents a compelling avenue towards the development of economic cobalt-free and high voltage(~5 V)lithium-ion ***,the elevated operational voltage of LNMO gives rise to pronounced interfacial interactions between the distorted surface lattices characterized by Jahn-Teller(J-T)distortions and the electrolyte ***,a localized crystallized coherent LaNiO_(3) and surface passivated Li_(3)PO_(4) layer is deposited on LNMO via a one-step calcination *** evidenced by transmission electron microscopy(TEM),time-of-flight secondary ion mass spectrometry(ToF-SIMS)and density functional theory(DFT)calculation,the epitaxial growth of LaNiO_(3) along the LNMO lattice can effectively stabilize the structure and inhibit irreversible phase transitions,and the Li_(3)PO_(4) surface coating can prevent the chemical reaction between HF and transition metals without sacrificing the electrochemical *** addition,the ionic conductive Li_(3)PO_(4) and atomic wetting inter-layer enables fast charge transfer transport ***,the LNMO material enabled by the lattice bonding and surface passivating features,demonstrates high performance at high current densities and good capacity retention during long-term *** rational design of interface coherent engineering and surface coating layers of the LNMO cathode material offers a new perspective for the practical application of high-voltage lithium-ion batteries.

关键词： high-voltage cathode interface-coherent surface passivating electrochemical performance

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Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System

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China Ocean Engineering 2024年第1期38卷 29-41页

作者： LI Yan-wei LIU Xiu-quan WANG Jin-long chen Guo-ming CHANG Yuan-jiang sheng Lei-xiang Centre for Offshore Engineering and Safety Technology China University of PetroleumQingdao 266580China National Engineering Laboratory of Offshore Geophysical and Exploration Equipment China University of PetroleumQingdao 266580China China CNOOC Research Institute Co. Ltd.Beijing 100028China

The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of *** approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex *** accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβ*** analysis program is also developed in MATLAB for dynamic *** simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation *** bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and *** platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.

关键词： deepwater drilling riser new hang-off system dynamic analysis finite element method penalty function method

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Frost heaving and crack initiation characteristics of tunnel rock mass in cold regions under low-temperature degradation

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Journal of Mountain Science 2024年第8期21卷 2844-2854页

作者： chen Wenhua xiang Tian School of Civil Engineering Beijing Jiaotong UniversityBeijing 202303China

Water freezing in rock fractures causes volumetric expansion and fracture development through frost *** study introduces a novel analytical model to investigate how uneven freezing force and surrounding rock pressure influence fracture initiation,based on mass conservation,elasticity,and water-ice phase transition principles.A model for rock fracture initiation considering freezing temperature,uneven freezing expansion,in-situ stress,and lateral pressure was proposed based on fracture *** for stress intensity factors were developed and validated using the phase field *** effects of rock elastic modulus anisotropy and critical fracture energy density on fracture initiation were also *** results show that the values of KI and KII exhibit an upward trend as the freezing temperature,uneven expansion,in-situ stress,and lateral pressure *** uneven freezing expansion has the most significant influence on KI and KII values among these *** the uneven freezing expansion coefficient increases to 0.5,the fracture initiation mode shifts from tensile fracture to shear *** the lateral pressure coefficient increases to 1,the fracture initiation mode shifts from tensile fracture to shear *** elastic modulus anisotropy causes fractures to propagate in a clockwise direction,forming a'butterfly'*** fracture energy density an isotropy causes counterclockwise deviation in propagation direction,resulting in branching paths and an'H'-shaped pattern.

关键词： Rock fractures Fracture water Uneven freezing expansion Phase field method Initiation angle Anisotropy

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Monothetic and conductive network and mechanical stress releasing layer on micron-silicon anode enabling high-energy solid-state battery

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Rare Metals 2024年第3期43卷 1017-1029页

作者： xiang Han Min Xu Lan-Hui Gu Chao-Fei Lan Min-Feng chen Jun-Jie Lu Bi-Fu sheng Peng Wang Song-Yan chen Ji-Zhang chen College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forestry ResourcesNanjing Forestry UniversityNanjing210037China Department of Physics Xiamen UniversityXiamen361005China Western Digital Corporation MilpitasCA95035USA

Silicon has ultrahigh capacity,dendrite-free alloy lithiation mechanism and low cost and has been regarded as a promising anode candidate for solid-state *** to the low infiltration of solid-state electrolyte(SSE),not the unstable solid-electrolyte interphase(SEI),but the huge stress during lithiation-and delithiation-induced particle fracture and conductivity lost tend to be the main *** this study,starting with micron-Si,a novel monothetic carbon conductive framework and a MgO coating layer are designed,which serve as electron pathway across the whole electrode and stress releasing layer,*** addition,the in situ reaction between Si and SSE helps to form a LiF-rich and mechanically stable SEI *** a result,the mechanical stability and charge transfer kinetics of the uniquely designed Si anode are significantly ***,high initial Coulombic efficiency,high capacity and durable cycling stability can be achieved by applying the Si@MgO@C anode in *** example,high specific capacity of 3224.6 mAh·g^(-1)and long cycling durability of 200 cycles are *** work provides a new concept for designing alloy-type anode that combines surface coating on particle and electrode structure design.

关键词： Lithium-ion battery(LIB) Solid-state electrolyte(SSE) Silicon anode Stress relief Coating

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