Mechanical responses of underground carriageway structures due to construction of metro tunnels beneath the existing structure:A case study

To understand the mechanical response pattern of the existing structure and ground due to the construction of metro tunnels underneath,the finite difference method is adopted to study the torsional deformation and stress variation of the existing structure and the effect of underground carriageway structures on the surface subsidence.The curves of the maximum differential subsidence,torsion angle,and distortion of the cross-section of the existing structure show two peaks in succession during traversing of two metro tunnels beneath it.The torsion angle of the existing structure changes when the two tunnels traverse beneath it in opposite directions.The first traversing of the shield tunnel mainly induces the magnitude variation in torsional deformation of the existing structure,but the second traversing of the subsurface tunnel may cause a dynamic change in the magnitude and form of torsional deformation in the existing structure.The shielding effect can reduce the surface subsidence caused by metro tunnel excavation to a certain extent,and the development trend of subsidence becomes slower as the excavation continues.

选择性凝血因子XI抑制剂在血栓性疾病治疗中的临床研究进展

血栓性疾病是当今社会的一个重要医疗问题,动脉内血栓形成是引起心肌梗死、缺血性脑卒中、急性肢体缺血的最常见原因,静脉内血栓则可能导致肢体缺血坏死及肺栓塞等严重后果,这些疾病每年共导致全球1000多万人死亡,占所有疾病死亡的50%以上,在过去的20年内,这一比例更是增加了25%~35%[1]。目前,抗凝剂是预防和治疗血栓形成的主要手段之一。

Analytical solution for evaluating deformation response of existing metro tunnel due to excavation of adjacent foundation pit

The excavation of foundation pit generates soil deformation around existing metro tunnel with shield driving method,which may lead to the deformation of tunnel lining.It is a challenge to evaluate the deformation of shield tunnel accurately and take measures to reduce the tunnel upward displacement as much as possible for geotechnical engineers.A new simplified analytical method is proposed to predict the longitudinal deformation of existing metro tunnel due to excavation unloading of adjacent foundation pit in this paper.Firstly,the additional stress of soils under vertical axisymmetric load in layered soil is obtained by using elastic multi-layer theory.Secondly,the metro tunnel is regarded as a Timoshenko beam supported by Winkler foundation so that the shear effect of tunnels can be taken into account.The additional stress acting on the tunnel due to excavation unloading in layered soil are compared with that in homogeneous soil.Additionally,the effectiveness of the analytical solution is verified via two actual cases.Moreover,parametric analysis is conducted to investigate the responses of the metro tunnel by considering such factors as the variation of subgrade coefficient,offset distance from the excavation center to tunnel longitudinal axis as well as equivalent shear stiffness.The proposed method can be used to provide theoretical basis for similar engineering project.

Analysis of the Development of the Commercial Space Around Metro Stations in Urban Core Areas Based on Place Making: A Case Study of Chunxi Road Metro Station in Chengdu

The metro is the most efficient and convenient public transport system in modern cities. For urban core areas in China, in which the metro was built later, there was more consideration for meeting the traffic needs of cities. However, there are few studies of collaborative planning for metro stations and their surrounding space. Thus, there is an urgent need to conduct research on collaborative planning for metro stations and their surrounding commercial space in urban core areas. Unlike conventional methods of integrated design of stations and cities, this paper, based on the theory of place spirit, took Chunxi Road Metro Station in Chengdu and its surrounding commercial space for example. It explored the pattern and characteristics of the place in the commercial space around the metro station, analyzed the strategies of cultural and commercial integration, as well as architecture, street, landscape and other aspects of the design method in the space, and explored the strategies of place-making and infiltration, providing a reference point for the development and place-making of the commercial space around metro stations in urban core areas.

How to Develop into An International Metropolis in the Context of the Silk Road Economic Belt —— A Case Study of Xi'an

For Xi'an,the central city of the Silk Road Economic Belt,it is both the theoretical and practical problem to develop into an international metropolis,so how to develop into an international metropolis becomes the research focus. This paper firstly introduces the necessity,the current situation and the evaluation index system of the construction of the city Xi'an in the context of the Silk Road Economic Belt; then it analyzes the econom ic developm ent of the three old districts,the three new districts,the three suburban districts and the four counties; and finally it puts forward the development path for Xi'an in the context of the Silk Road Economic Belt — the development pattern of "five districts,one international harbor area and two bases""nine-grid-pattern "economic development and the function-oriented coordinated development of the regional economy.

Spatiotemporal Evolution Characteristics of Urban Land Surface Temperature Based on Local Climate Zones in Xi’an Metropolitan,China

Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.

Last train timetable optimization for metro network to maximize the passenger accessibility over the end-of-service period

Purpose-This study aims to improve the passenger accessibility of passenger demands in the end-ofoperation period.Design/methodology/approach-A mixed integer nonlinear programming model for last train timetable optimization of the metro was proposed considering the constraints such as the maximum headway,the minimum headway and the latest end-of-operation time.The objective of the model is to maximize the number of reachable passengers in the end-of-operation period.A solution method based on a preset train service is proposed,which significantly reduces the variables of deciding train services in the original model and reformulates it into a mixed integer linear programming model.Findings-The results of the case study of Wuhan Metro show that the solution method can obtain highquality solutions in a shorter time;and the shorter the time interval of passenger flow data,the more obvious the advantage of solution speed;after optimization,the number of passengers reaching the destination among the passengers who need to take the last train during the end-of-operation period can be increased by 10%.Originality/value-Existing research results only consider the passengers who take the last train.Compared with previous research,considering the overall passenger demand during the end-of-operation period can make more passengers arrive at their destination.Appropriately delaying the end-of-operation time can increase the proportion of passengers who can reach the destination in the metro network,but due to the decrease in passenger demand,postponing the end-of-operation time has a bottleneck in increasing the proportion of passengers who can reach the destination.

Comparative Analysis of the Factors Influencing Metro Passenger Arrival Volumes in Wuhan, China, and Lagos, Nigeria: An Application of Association Rule Mining and Neural Network Models

This study explores the factors influencing metro passengers’ arrival volume in Wuhan, China, and Lagos, Nigeria, by examining weather, time of day, waiting time, travel behavior, arrival patterns, and metro satisfaction. It addresses a significant research gap in understanding metro passengers’ dynamics across cultural and geographical contexts. It employs questionnaires, field observations, and advanced data analysis techniques like association rule mining and neural network modeling. Key findings include a correlation between rainy weather, shorter waiting times, and higher arrival volumes. Neural network models showed high predictive accuracy, with waiting time, metro satisfaction, and weather being significant factors in Lagos Light Rail Blue Line Metro. In contrast, arrival patterns, weather, and time of day were more influential in Wuhan Metro Line 5. Results suggest that improving metro satisfaction and reducing waiting times could increase arrival volumes in Lagos Metro while adjusting schedules for weather and peak times could optimize flow in Wuhan Metro. These insights are valuable for transportation planning, passenger arrival volume management, and enhancing user experiences, potentially benefiting urban transportation sustainability and development goals.

Regenerative Braking Energy Recovery System of Metro Train Based on Dual-Mode Power Management

In order to fully utilize the regenerative braking energy of metro trains and stabilize the metro DC traction busbar voltage,a hybrid regenerative braking energy recovery system with a dual-mode power management strategy is proposed.Firstly,the construction of the hybrid regenerative braking energy recovery system is explained.Then,based on the power demand of low-voltage load in metro stations,a dual-mode power management strategy is proposed to allocate the reference power of each system according to the different working conditions,and the control methods of each system are set.Finally,the correctness and effectiveness of the dual-mode strategy are verified through simulation,and the proposed braking energy utilization scheme is compared with other singleform utilization schemes.The results illustrate that the hybrid system with the dual-mode strategy can effectively recycle the regenerative braking energy of metro train and inhibit the busbar voltage fluctuation;the proposed braking energy utilization scheme has certain advantages on energy recovery and DC bus voltage stabilization compared with other single-form schemes;the proposed power management strategy can correctly allocate the reference power of each system with a lower construction cost.

终末期肝病模型-XI评分对急性心肌梗死冠状动脉支架植入术后患者预后的预测价值

目的 探讨终末期肝病模型-XI(MELD-XI)评分对急性心肌梗死患者冠状动脉支架植入术后的预后的预测价值。方法 回顾性收集2021年1月至2022年12月于内蒙古医科大学附属医院收治的急性心肌梗死患者226例,根据入院时MELD-XI评分,将患者分为高MELD-XI评分组和低MELD-XI评分组,每组各113例。比较两组患者近、远期预后。结果 与低MELD-XI评分组比较,高MELD-XI评分组患者左室射血分数(LVEF)显著降低[(51.67±7.91)%vs.(60.91±5.91)%],(P<0.001);N末端脑钠肽前体(NT-proBNP)显著增高(822.87±462.38) vs.(701.84±338.21)ng/L,(P=0.026)。与低MELD-XI评分组比较,高MELD-XI评分组患者不良结局事件的发生率显著增高(16.81%vs. 6.19%,P=0.012)。MELD-XI评分对急性心肌梗死冠状动脉支架植入术后不良结局事件具有一定的预测价值,曲线下面积为0.732,95%CI:0.671~0.798,(P<0.001)。结论 MELD-XI对于预测急性心肌梗死患者预后具有一定的参考价值。

Types, Distribution Characteristics, and Development Strategies of Rural Characteristic Industry in Xi’an Metropolitan Area

China’s urbanization development has entered the“second half”,which is at a critical stage of transition from the middle stages to the mature stage.The metropolitan area formed by the mega-city radiating the development of surrounding cities and counties is an important spatial carrier of urbanization.The rural characteristic industry is the main path to promote regional economic development and urban-rural integration in the metropolitan area.Exploring the development characteristics of rural characteristic industries in the metropolitan area has important theoretical and practical significance for promoting the effective connection between urban-rural integration and rural revitalization of the metropolitan area and improving the development quality of the metropolitan area.Take the Xi’an metropolitan area as an example and adopt kernel density analysis and other methods to reveal the spatial differentiation rules of rural characteristic industries.On this basis,the three-dimensional development strategy of“industry-spatial-institutional”for the development of the rural characteristic industry is proposed,to provide theoretical reference for the development of rural characteristic industry in metropolitan areas.

Fatigue research of metro car body based on operational loads

Purpose–The principle of infinite life design currently directs fatigue resistance strategies for metro car bodies.However,this principle might not fully account for the dynamic influence of operational loads and the inevitable presence of defects.This study aims to integrate methods of service life estimation and residual life assessment,which are based on operational loads,into the existing infinite life verification framework to further ensure the operational safety of subway trains.Design/methodology/approach–Operational loads and fatigue loading spectra were determined through the field test.The material test was conducted to investigate characteristics of the fracture toughness and the crack growth rate.The fatigue strength of the metro car body was first verified using the finite element method and Moore–Kommers–Japer diagrams.The service life was then estimated by applying the Miner rule and high-cycle fatigue curves in a modified form of the Basquin equation.Finally,the residual life was assessed utilizing a fracture assessment diagram and a fitted curve of crack growth rate adhered to the Paris formula.Findings–Neither the maximum utilization factor nor the cumulative damage exceeds the threshold value of 1.0,the metro car body could meet the design life requirement of 30 years or 6.6 million km.However,three out of five fatigue key points were significantly influenced by the operational loads,which indicates that a single fatigue strength verification cannot achieve the infinite life design objective of the metro car body.For a projected design life of 30 years,the tolerance depth is 12.2 mm,which can underscore a relatively robust damage tolerance capability.Originality/value–The influence of operational loads on fatigue life was presented by the discrepancy analysis between fatigue strength verification results and service life estimation results.The fracture properties of butt-welded joints were tested and used for the damage tolerance assessment.The damage tolerance life can be effectively related by a newly developed equation in this study.It can be a valuable tool to provide the theoretical guidance and technical support for the structural improvements and maintenance decisions of the metro car body.

Comparative Analysis of Metro Passengers’Mobility Patterns and Jobs-housing Balance of Metropolitan

The advent of the big data era has provided many types of transportation datasets,such as metro smart card data,for studying residents’mobility and understanding how their mobility has been shaped and is shaping the urban space.In this paper,we use metro smart card data from two Chinese metropolises,Shanghai and Shenzhen.Five metro mobility indicators are introduced,and association rules are established to explore the mobility patterns.The proportion of people entering and exiting the station is used to measure the jobs-housing balance.It is found that the average travel distance and duration of Shanghai passengers are higher than those of Shenzhen,and the proportion of metro commuters in Shanghai is higher than that of Shenzhen.The jobs-housing spatial relationship in Shenzhen based on metro travel is more balanced than that in Shanghai.The fundamental reason for the differences between the two cities is the difference in urban morphology.Compared with the monocentric structure of Shanghai,the polycentric structure of Shenzhen results in more scattered travel hotspots and more diverse travel routes,which helps Shenzhen to have a better jobs-housing balance.This paper fills a gap in comparative research among Chinese cities based on transportation big data analysis.The results provide support for planning metro routes,adjusting urban structure and land use to form a more reasonable metro network,and balancing the jobs-housing spatial relationship.

Research on passenger flow control at metro transfer stations based on real-time flow calculation of streamlines

Purpose – The volume of passenger traffic at metro transfer stations serves as a pivotal metric for theorchestration of crowd flow management. Given the intricacies of crowd dynamics within these stations andthe recurrent instances of substantial passenger influxes, a methodology predicated on stochastic processesand the principle of user equilibrium is introduced to facilitate real-time traffic flow estimation within transferstation streamlines.Design/methodology/approach – The synthesis of stochastic process theory with streamline analysisengenders a probabilistic model of intra-station pedestrian traffic dynamics. Leveraging real-time passengerflow data procured from monitoring systems within the transfer station, a gradient descent optimizationtechnique is employed to minimize the cost function, thereby deducing the dynamic distribution of categorizedpassenger flows. Subsequently, adhering to the tenets of user equilibrium, the Frank–Wolfe algorithm isimplemented to allocate the intra-station categorized passenger flows across various streamlines, ascertainingthe traffic volume for each.Findings – Utilizing the Xiaozhai Station of the Xi’an Metro as a case study, the Anylogic simulation softwareis engaged to emulate the intra-station crowd dynamics, thereby substantiating the efficacy of the proposedpassenger flow estimation model. The derived solutions are instrumental in formulating a crowd controlstrategy for Xiaozhai Station during the peak interval from 17:30 to 18:00 on a designated day, yielding crowdmanagement interventions that offer insights for the orchestration of passenger flow and operationalgovernance within metro stations.Originality/value – The construction of an estimation methodology for the real-time streamline traffic flowaugments the model’s dataset, supplanting estimated values derived from surveys or historical datasets withreal-time computed traffic data, thereby enhancing the precision and immediacy of crowd flow managementwithin metro stations.

System and Realization Path of Xi Jinping's Eco-poverty Alleviation Concept under the Vision of Green Development

Since the 18 th National Congress of the Communist Party of China,General Secretary Xi Jinping delivered a series of speeches on ecological environment and poverty governance,forming the Xi Jinping's eco-poverty alleviation ideology.In this paper,the Xi Jinping's eco-poverty alleviation ideology is taken as the research object.Using the methods of literature analysis and comparative analysis,the origin of eco-poverty alleviation theory is explored from the common prosperity theory and the theory of ecological capital,and the practice foundation is found out from practical cases.The relationship between the ecological damage and poverty is systematically analyzed,and the mechanism of ecological poverty is explored in detail.The basic connotation of Xi Jinping's eco-poverty alleviation is expounded,and it consists of three parts:guiding ideology layer,implementation layer,and guarantee layer.By perfecting and innovating the market mechanism,social management mechanism,performance evaluation mechanism,integration mechanism with other poverty alleviation methods,and ecological immigration mechanism of ecological poverty,the realization of Xi Jinping's eco-poverty alleviation concept could be guaranteed.

English Translation of Chinese Natural Ecological Discourse:A Corpus-based Case Study on Xi Jinping:The Governance of China

Amid the increasingly severe global natural eco-environment,it is necessary to build a natural ecological civilization by constructing an ecological civilization discourse.Against this background,this study compiles a corpus of natural ecological discourse in the English translation of Xi Jinping:The Governance of China(short for Xi).By using Wordsmith and AntConc,this study explores the linguistic features of the ecological discourse in English translation of Xi in the following dimensions,including high-frequency words,keywords,word collocations,concordance lines.This study aims to analyze the concepts and attitudes towards natural ecology,so as to provide certain valuable insights for the construction of China’s discourse on natural ecological civilization.The study found that the natural ecology discourse involving in the English translation of Xi turned out to be ecologically beneficial.

达芬奇机器人(Xi)辅助下直肠前切除术(NOSES-Ⅳ式)

达芬奇机器人(Xi)系统联合经自然腔道取标本(NOSES)在直肠癌手术中的应用日益成熟和普遍.二者的结合充分发挥了各自的优势,将层面的游离,淋巴的清扫,血管的解剖,神经的保护和无菌、微创理念贯穿始终.因此,机器人下的手术操作,规范的手术流程,经自然腔道取标本的微创模式,为程序化的直肠癌根治手术带来了新的进步.

杜梨LRR-XI-a亚家族的鉴定及调控腐烂病抗性的成员筛选

为探究LRR-XI-a基因家族在杜梨免疫系统中的作用机制,基于GDR数据库的杜梨基因组数据鉴定了杜梨LRR-XI-a家族成员,经进化特征、基因重复事件和表达模式分析筛选了响应腐烂病信号的成员,并结合果实瞬时表达和抗性基因表达分析对部分成员的功能进行了初步分析。结果表明,杜梨LRR-XI-a基因家族包含91个成员,进化上可分为6个亚组。基因重复分析结果表明,杜梨中GroupⅠ成员数的迅速增加可能由串联复制(TD)和全基因组复制(WGD)共同导致,而GroupⅥ成员的增加仅由WGD所致。顺式作用元件分析结果表明,杜梨LRR-XI-a亚组Ⅱ和Ⅵ可能主要参与杜梨对非生物逆境信号的响应,而其余4个亚组同时参与对生物和非生物逆境信号的响应。表达分析结果表明,LRR-XI-4和LRR-XI-5在腐烂病侵染后呈不同程度的上调表达,其中LRR-XI-5上调表达量可达对照的586倍以上。果实瞬时表达分析结果表明,过表达LRR-XI-4和LRR-XI-5降低了梨果实对腐烂病的抗性,抑制了JA信号通路基因的表达,但激活了超敏反应响应基因的表达。综上,基因重复导致杜梨LRR-XI-a家族成员发生迅速增加;LRR-XI-a家族成员响应不同的生物胁迫和非生物胁迫;LRR-XI-4和LRR-XI-5通过激活超敏反应(HR)相关基因的表达负调控腐烂病抗性,可作为后期腐烂病抗性研究的候选基因。本研究结果为后续开展梨抗病机理研究和分子育种奠定了基础。

基于PLAXIS3D的地铁近接基坑开挖稳定性分析

文中针对城市地铁运营保护区内基坑开挖施工现状,结合类似工程经验对比法,充分考虑土体与结构的共同作用,以及分步开挖的施工过程,运用有限元软件(PLAXIS 3D)进行三维数值模拟分析,分别从加载效应、卸载效应、横向效应、纵向效应及空间效应等方面,分析了地铁保护区内基坑开挖对既有地铁隧道稳定性的影响,并提出相应对策。该方法对评估地下结构近接基坑开挖的安全稳定、指导现场施工具有很强的现实意义。

地铁大语言模型垂直问答系统MetroGPT

为解决城市轨道交通大系统中各个运行层级间不协调与信息资源浪费的问题,以地铁系统为原型,分析地铁大系统的运作机制,设计易于实现的地铁大模型问答系统(MetroGPT)。MetroGPT是基于大语言模型(LLM)构建的地铁大语言模型垂直问答系统,以LangChain为设计框架,针对特定场景定制不同的AI智能体完成特定任务。基于现有的6种大语言模型制作垂域智能体,使用改进的德尔菲法设计评估流程,通过德尔菲法的评分结果选出与地铁某类垂域知识最为匹配的大语言模型引擎。研究结果表明:MetroGPT提供1种解决地铁运行系统中层级信息闭塞、交流不充分的方法,为运营方、乘客、服务人员提供1个三方交流平台,在不同条件下针对需求制定合乎规范与实际的解决方案。通过分析现有技术和挑战,提出1种结合知识图谱和大语言模型的问答系统设计方案,并讨论其在地铁运营中的具体应用场景和潜在价值。