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Construction of shallow buried large-span metro stations using the small pipe roof-beam method

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 122-136页

作者： Qian BAI Wen ZHAO Yingda ZHANG Pengjiao JIA Xiangrui MENG Bo LU Xin WANG Dazeng SUN School of Resources and Civil Engineering Northeastern UniversityShenyang 110819China Centre for Infrastructure Engineering and Safety School of Civil and Environmental EngineeringThe University of New South WalesNSW 2052Australia School of Rail transportation Soochow UniversitySuzhou 215131China China Northeast Architectural Design and Research institute Co. Ltd.Shenyang 110006China

In relation to the Shifu Road Station project on Line 4 of the Shenyang Metro in China,a small-pipe roof-beam method for constructing subway stations is ***,a numerical simulation was performed to optimize the supporting parameters of the proposed method and determine the design ***,the deformation of the pipe roof and surface settlement during the construction process were ***,the surface settlement attributed to the excavation was studied through field monitoring,and the proposed method was compared with other *** results show that an increase in the pipe-roof spacing has little effect on the surface settlement and piperoof *** bearing capacity of the pipe roof can be efficiently utilized once the flexural stiffness reaches 2EI,and the flexural stiffness is not the dominant factor controlling the *** essential stages in controlling surface settlement are the excavations of the transverse pilot tunnels and the soil between *** final settlement value of the ground was 24.1 mm,resulting in a reduction in the construction period by at least five months while satisfying the control requirements.

关键词： subway station pipe-roof method surface settlement simulation on-site monitoring

Evaluating the thermal environment of urban land surfaces in Yakutsk,a city located in a region of continuous permafrost

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Advances in Climate Change Research 2024年第1期15卷 113-123页

作者： Xiang-Long LI Ze ZHANG Jin-Xin LU Anatoli BROUCHKOV Qing-Kai YAN Qi-Hao YU Sheng-Rong ZHANG Andrey MELNIKOV School of Civil Engineering and transportation Institute of Cold Regions Science and EngineeringPermafrost InstituteNortheast Forestry UniversityHarbin150040China China Railway Qinghai-Tibet Group Company Xining 810000China Department of Geocryology Faculty of GeologyLomonosov Moscow State UniversityMoscow 119234Russian Federation State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco Envi ronment and Re sourcesChinese Academy of SciencesLanzhou 730000China Melnikov Permafrost institute Siberian BranchRussian Academy of ScienceYakutsk 677010Russian Federation

Rapid urbanization has led to changes in the urban land surface thermal ***,there are still much unknown about the urban land surface thermal conditions in permafrost *** is a unique geological environment,changes in the urban land surface thermal environment may trigger geological disasters caused by permafrost *** study utilized remote sensing data and geographic de-tectors to identify the dynamic changes in land surface temperature(LST)and land use/land cover(LU/LC)in Yakutsk,as well as the potential factors contributing to LST *** 1992 and 2020,the built-up area in Yakutsk increased by 36%,and the annual average LST in Yakutsk has risen by 6.67℃,accompanied by an expansion of high-temperature *** ongoing greening efforts,rapid urbanization poses a threat to these green *** in the normalized difference built-up index(NDBI)and land use transfer(LDT)were identified as the primary drivers of urban LST *** integrating geographic detector technology and artificial neural network models,we optimized the selection of input factors in the prediction model and used it to explore the future changes in LST in *** average LST in Yakutsk is expected to reach 23.4℃ and 25.1℃ in 2030 and 2040,respectively,with a further increase in high-temperature *** study provides a reference for ecological,hydrological,and geological assessments of cities in permafrost regions.

关键词： Remote sensing Land surface temperature Land use/Land cover Permafrost Yakutsk

Persistence of fertilization effects on soil organic carbon in degraded alpine wetlands in the Yellow River source region

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Journal of Mountain Science 2024年第4期21卷 1358-1371页

作者： DUAN Peng WEI Rongyi WANG Fangping LI Yongxiao SONG Ci HU Bixia YANG Ping ZHOU Huakun YAO Buqing ZHAO Zhizhong Qinghai University Xining 810016China Qinghai transportation Planning and Design institute Co.Ltd Xining 810000China Key Laboratory of Adaptation and Evolution of Plateau Biota Chinese Academy of SciencesXining 810008China Key Laboratory of Restoration Ecology of Cold Area in Qinghai Province Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810008China Qinghai University of Science and Technology Xining 810016China

In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon ***,it is currently unclear whether these effects are *** study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics,soil physicochemical properties,and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen,phosphorus,and organic mixed *** following results were obtained:The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded *** months after fertilization,nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands,whereas after 15 months,organic compost enhanced the soil organic carbon level in severely degraded *** equation modeling indicates that fertilization decreases the soil pH and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of *** months after fertilization,nitrogen fertilizer showed a direct positive effect on soil organic ***,organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil *** 15 months,none of the fertilizers significantly affected the soil organic carbon *** summary,it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.

关键词： Degraded alpine wetlands Fertilizer Soil organic carbon Temporal variation Vegetation aboveground biomass Yellow River source region

An Interpolation Method for Karhunen-Loève Expansion of Random Field Discretization

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工程与科学中的计算机建模(英文) 2024年第1期138卷 245-272页

作者： Zi Han Zhentian Huang Department of Engineering Mechanics Hohai UniversityNanjing211100China College of Civil and transportation Engineering Shenzhen UniversityGuangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and UtilizationInstitute of Deep Earth Sciences and Green EnergyShenzhenChina

In the context of global mean square error concerning the number of random variables in the representation,the Karhunen–Loève(KL)expansion is the optimal series expansion method for random field *** computational efficiency and accuracy of the KL expansion are contingent upon the accurate resolution of the Fredholm integral eigenvalue problem(IEVP).The paper proposes an interpolation method based on different interpolation basis functions such as moving least squares(MLS),least squares(LS),and finite element method(FEM)to solve the *** with the Galerkin method based on finite element or Legendre polynomials,the main advantage of the interpolation method is that,in the calculation of eigenvalues and eigenfunctions in one-dimensional random fields,the integral matrix containing covariance function only requires a single integral,which is less than a two-folded integral by the Galerkin *** effectiveness and computational efficiency of the proposed interpolation method are verified through various one-dimensional ***,based on theKL expansion and polynomial chaos expansion,the stochastic analysis of two-dimensional regular and irregular domains is conducted,and the basis function of the extended finite element method(XFEM)is introduced as the interpolation basis function in two-dimensional irregular domains to solve the IEVP.

关键词： Random field discretization KL expansion IEVP MLS FEM stochastic analysis

A Fluorinated,Ion-Conducting and Adaptive Supramolecular Polymer Protective Layer for Stabilizing Lithium Metal Anodes

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CCS Chemistry 2024年第5期6卷 1157-1164页

作者： Tao Chen Bo Qin Yuncong Liu Zhekai Jin Haiping Wu Chao Wang Xi Zhang institute of Smart City and Intelligent transportation Southwest Jiaotong UniversityChengdu 610032 Key Lab of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084 Department of Battery Technology BYD Shanghai Co.Ltd.Shanghai 201611

Perfluoropolyether(PFPE)is a promising material for protective coatings on Li metal anodes due to its chemical inertness and minimal swelling in ***,a conventional PFPE coating with poor ionic conductivity and mechanical stability is still not satisfactory for long-term cycling of Li ***,we design and synthesize an adaptive and high-conductivity supramolecular polymer(PFPE-EG-I).This polymer is constructed from PFPE chains,ethylene glycol(EG)segments,and hydrogen-bonding moieties derived from isophoronediisocyanate,serving as a multifaceted artificial solid electrolyte interphase(SEI).The incorporated EG segments enhance the Li+conductivity of the SEI,and the hydrogen-bonding units introduce a dynamic self-adaptive behavior to the polymer matrix.A solution-processed PFPE-EG-I coating is demonstrated to promote uniform Li deposition and mitigate side reactions between Li and the ***,this leads to enhanced coulombic efficiency and prolonged cycle longevity in lithium metal batteries(LMBs).The innovative design of this multifunctional artificial SEI offers a promising avenue for the realization of dendrite-free Li anodes,paving the way for the advancement of high-performance LMBs.

关键词： supramolecular polymers batteries lithium anodes artificial solid electrolyte interphase perfluoropolyether

A novel method for modeling the phase change of iron ore particles in the cohesive zone of a blast furnace

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Particuology 2024年第3期86卷 252-261页

作者： Dianyu E Yingming Wen Jiayun Dan Youyuan Jiang Guangchao Wei Jiaxin Cui Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and TechnologyNanchang330013China International institute for Innovation Jiangxi University of Science and TechnologyNanchang330013China Ironmaking Plant Xiangtan Iron and Steel Corporation of Hunan HualingXiangtan411101China Schoolof transportation and Vehicle Enginering Shandong University of TechnologyZibo255000China

Cohesive zone plays a vital role in the stable operation of a blast furnace(BF),yet the complex phase change process of iron ore particles in this zone is still not well *** this study,a novel one-dimensional(1D)unsteady phase change model was developed to elucidate the heat transfer and melting mechanisms of iron ore *** model validation,the effects of several key operating parameters(e.g.,particle diameter,gas velocity,initial temperature)on the phase change behavior of iron ore particles were analyzed,and the joint effect of multiple parameters was *** results show that larger-sized iron ore particles possess lower specific surface areas,which in turn reduces their convective heat absorption ***,the distance from the solid-liquid phase interface to the particle surface increases,thereby slowing down the movement of the phase interface and pro-longing the melting duration of the *** the gas velocity and the initial temperature does not have a significant impact on reducing the duration of the complete melting *** the specified conditions,it is observed that increasing the gas velocity by 3-fold and 9-fold results in a reduction of the melting duration by 2.4%and 8.3%,*** the initial temperature of iron ore particles results in a decrease in the core-to-surface temperature difference,a slower heating rate,and a shorter duration to achieve *** the factors affecting the melting process,the particle diameter is found to be the most significant in terms of the liquid phase precipitation,mushy zone thickness,and core-to-surface temperature difference of iron ore particles.

关键词： Blast furnace Iron ore melting Cohesive zone Heat transfer Phase change

Train post‑derailment behaviours and containment methods:a review

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Railway Engineering Science 2024年第1期32卷 59-80页

作者： Zhao Tang Yuwei Hu Shuangbu Wang Liang Ling Jianjun Zhang Kaiyun Wang State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China institute of Smart City and Intelligent transportation Southwest Jiaotong UniversityChengdu 610031China National Centre for Computer Animation Bournemouth UniversityDorsetUK

Railway accidents,particularly serious derailments,can lead to catastrophic ***,it is essential to prevent derailment escalation to reduce the likelihood of severe *** post-derailment behaviours and containment methods play a critical role in preventing derailment escalation and providing passive safety protection and accident prevention in the event of a ***,despite the increasing attention on this field from academia and industry in recent years,there is a lack of systematic exploration and summarization of emerging applications and containment methods in train post-derailment *** this reason,this paper presents a comprehensive review of existing studies on train post-derailment behaviours,encompassing various topics such as post-derailment contact-impact models,dynamic modelling and simulation techniques,and the primary factors influencing post-derailment ***,this review introduces and elucidates substitute guidance mechanisms(SGMs),which serve as railway-specific passive safety protection and accident prevention *** various types of SGMs are depicted,and their ongoing developments and applications are explored in *** review additionally points out several unresolved challenges including the adverse effects of SGMs,and proposes future research directions to advance the theoretical understanding and practical application of train post-derailment behaviours and containment *** review seeks to be a valuable reference for railway industry professionals in preventing catastrophic derailment consequences through post-derailment containment methods.

关键词： Railway passive safety Railway accident prevention Post-derailment behaviours Substitute guidance mechanisms(SGMs) Contact-impact model

Technologies and studies of gas exchange in two-stroke aircraft piston engine:A review

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Chinese Journal of Aeronautics 2024年第1期37卷 24-50页

作者： Yu ZHOU Xueyu LI Shuiting DING Shuai ZHAO Kun ZHU Longtao SHAO Farong DU Gerui WANG Zheng XU Research institute of Aero-Engine Beihang UniversityBeijing 100191China Aircraft/Engine Integrated System Safety Beijing Key Laboratory Beijing 100191China School of transportation Science and Engineering Beihang UniversityBeijing 100191China Civil Aviation University of China Tianjin 300300China Aero Engine Academy of China Beijing 101304China School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beihang Hangzhou Innovation institute Yuhang Hangzhou 310052China

The in-cylinder gas exchange process is crucial to the power performance of two-stroke aircraft piston engines,which is easily influenced by complex factors such as high-altitude performance variation and in-cylinder flow *** paper reviews the development history and characteristics of gas exchange types,as well as the current state of theory and the validation methods of gas exchange technology,while also discusses the trends of cutting-edge technologies in the *** paper provides a theoretical foundation for the optimization and engineering design of gas exchange systems and,more importantly,points out that the innovation of gas exchange types,the modification of theoretical models,and the technology of variable airflow organization are the key future research directions in this field.

关键词： Aircraft piston engine Aircraft power systems Gas exchange High-altitude performance In-cylinder flow Two-stroke Unmanned Aerial Vehicles(UAVs)

Ionic potency regulation of coagulation bath induced by saline solution to control over the pore structure of PBI membrane for highperformance lithium metal batteries

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Journal of Energy Chemistry 2024年第7期94卷 288-298页

作者： Arshad Hussain Waseem Raza Andleeb Mehmood Sana Jalees Lihong Ao Yonggui Deng Aymeric Ramiere Xingke Cai Dongqing Liu College of Civil and transportation Engineering Shenzhen UniversityShenzhen 518060GuangdongChina institute for Advanced Study Shenzhen UniversityShenzhen 518060GuangdongChina institute of Carbon Neutrality Zhejiang Wanli UniversityNingbo 315100ZhejiangChina College of Light Industry and Chemical Engineering Dalian Polytechnic UniversityDalian 116034LiaoningChina College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060GuangdongChina College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060GuangdongChina

In this study,we have explored the use of water as a non-solvent for tuning the microstructure of poly-benzimidazole(PBI)membranes,which are potential separators for lithium metal batteries(LMBs).The traditional method for membrane synthesis called nonsolvent-induced phase separation(NIPS),usually relies on hazardous and costly organic *** dissolving sodium chloride(Nacl)in water,we could adjust the water ionic potency and the exchange speed of the non-solvent with the DMAC solution to change the micropore structure of the PBI *** increasing Nacl concentration,the micro-pores in the PBI membrane transitioned from finger-like to sponge-like *** to com-mercial separators like the Celgard separator,the PBI membrane with sponge-like micropores exhibited better regulation of lithium deposition and improved Li^(+) transportation capability due to its good wetta-bility with the ***,the PBI membrane-based Li/Li symmetric cell and Li/LiFePO_(4) full cell demonstrated superior performance compared to the Celgard-based *** research proposes an eco-friendly and scalable synthetic approach for fabricating commercial separators for LMBs,addressing the issue of lithium dendrite growth and improving overall battery safety and performance.

关键词： Lithium metal-based battery Salt-induced Polybenzimidazole Tunablemorphology lonic potency