Transportation

交通运输
  • 文章类型: Journal Article
    共享电动踏板车(SE)旅行是一种低碳运输方式,可以通过与地铁系统集成来进一步增强。本研究旨在量化建筑环境的影响,态度偏好,天气感知,以及其他因素对使用“SE-地铁换乘”出行方式的评价和意向,以及如何有效和简洁地测量和建模这些影响。利用长沙市的问卷调查数据进行了实证分析,中国,调查了683名参与者。基于技术接受模型(TAM)建立并比较了三种满意度模型,并扩展了一个最优的M2模型,以纳入用户对天气的主观感知,提出了一种简化问卷长度的方法。研究发现,精心设计的车辆和基础设施,以及必要的配套设施,在提高SE使用率方面发挥重要作用。然而,长沙的SE政策还有很多需要优化的地方。尽管SE在地形和身体素质方面有优势,与传统共享单车相比,它们的用户群显著扩大和改变,适应中老年用户群体的潜力仍然很大。这项研究的结果可以为专业人士和政府官员在设计系统时提供有价值的见解,建设基础设施,制定政策。
    Shared E-scooter (SE) travel is a low-carbon transportation method that can be further enhanced by integrating with metro systems. This study aims to quantify the impact of the built environment, attitude preferences, weather perception, and other factors on the evaluation and intention to use the \"SE-metro transfer\" travel mode, as well as how to efficiently and concisely measure and model these effects. Empirical analysis was conducted using questionnaire data from Changsha, China, with 683 participants surveyed. Three satisfaction models were established and compared based on the Technology Acceptance Model (TAM), and an optimal M2 model was expanded to incorporate users\' subjective perceptions of weather, proposing a method to simplify questionnaire length. The study found that well-designed vehicles and infrastructure, along with necessary supporting facilities, play important roles in enhancing SE usage. However, there are still many areas for optimization in Changsha\'s SE policies. Despite the advantages of SE in terrain and physical fitness, which have significantly expanded and changed their user base compared to traditional shared bicycles, there is still much potential to adapt to the middle-aged and older user groups. The results of this study can provide valuable insights for professionals and government officials in designing systems, constructing infrastructure, and formulating policies.
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  • 文章类型: Journal Article
    The construction of road infrastructure has resulted in the degradation of wildlife habitat and the decrease of ecological network connectivity and stability. Studying the impacts of road infrastructure on wildlife life and migration is significant for regional wildlife conservation and ecological network optimization. We assessed the impacts of road infrastructure on habitat suitability using the MaxEnt model based on wildlife occurrence point data in the Guangdong-Hong Kong-Macao Greater Bay Area. We constructed the ecological networks and identified ecological breakpoints using the minimum cumulative resistance model, and compared the ecological network connectivity of different scenarios with the landscape connectivity index and graph theory index. The results showed that railway and motorway significantly affected habitat suitability, causing a decrease in wildlife habitat suitability. Affected by road infrastructure, the fragmentation of ecological sources intensified, the resistance of ecological corridors increased, and the ecological network connectivity and stability significantly decreased. A total of 536 ecological breakpoints were identified, which were concentrated in the area adjacent to ecological sources. The results would provide important scientific references for wildlife habitat conservation and ecological restoration in the Guangdong-Hong Kong-Macao Greater Bay Area.
    道路基础设施的建设导致野生动物栖息地生境退化,以及生态网络连通性和稳定性降低等问题。研究道路基础设施对野生动物生活和迁徙的影响,对区域野生动物保护和生态网络优化具有重要意义。本研究基于野生动物的出现点位数据,利用MaxEnt模型评估粤港澳大湾区道路基础设施对生境适宜性的影响,采用最小累计阻力模型构建生态网络并识别生态断裂点,同时,使用景观连通性指数与图论指数对比不同情景的生态网络连通性。结果表明: 研究区内部的铁路和高速公路对生境适宜性产生显著影响,造成野生动物栖息地适宜性降低;受道路基础设施的影响,生态源地破碎化加剧,生态廊道的通行阻力增加,生态网络的连通性和稳定性明显下降;共识别生态断裂点536处,集中分布于生态源地附近。研究结果可为粤港澳大湾区野生动物栖息地保护和生态网络连通性修复提供重要的科学参考。.
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  • 文章类型: Journal Article
    地铁车站周边合理的土地利用开发,可以平衡地铁系统在高峰和非高峰时段的利用率,从而提高其服务水平和运营效率。分析客流的时间分布格局及其影响因素对于确定地铁车站周边各土地利用类型的最佳比例至关重要。因此,本文首先采用主成分分析(PCA)来研究地铁乘客量的时间分布,并确定它们的主要模式和因素负荷。然后,使用地理加权回归,研究考察了主要成分比例和影响因素之间的空间依赖性,集中在西安地铁站。结果表明,客流的时间分布可以分解为三个主要成分:第一个代表通勤特征,第二个和第三个代表调节功能。总体分布是这些组分以不同比例的复合物。住宅和教育用地用途主要驱动早晚高峰流量,与过渡地区相比,市中心和周边地区的住宅用地使用效果更为明显。相反,商业和办公,healthcare,休闲和公园用地可缓解高峰流量并增加非高峰流量。外部枢纽增强全天客流,而工业用地的影响可以忽略不计。
    A reasonable land use development around subway stations can balance the utilization rates of the subway system during peak and off-peak hours, thereby enhancing its service levels and operational efficiency. Analyzing the temporal distribution patterns of passenger flow and their influencing factors is crucial for determining the optimum ratio of each land use type surrounding metro stations. Thus, this paper employs principal component analysis (PCA) at first to investigate the temporal distribution of metro ridership, and identify their main patterns and factor loadings. Then, using geographically weighted regression, the study examines the spatial dependencies between the main component proportions and influencing factors, focusing on Xi\'an subway stations. The results indicate that the temporal distribution of passenger flow can be decomposed into three principal components: the first representing commuting characteristics, and the second and third representing regulating functions. The overall distribution is a composite of these components in varying proportions. Residential and educational land uses primarily drive morning and evening peak flows, with residential land use in the city center and peripheral areas having a more pronounced effect compared to transitional areas. Conversely, commercial & office, healthcare, and recreational & park land mitigate peak flows and increase off-peak flows. External hub enhances passenger flow throughout the day, while industrial land use has negligible impact.
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  • 文章类型: Journal Article
    农药在中国的广泛应用导致了土壤中残留的积累。然而,很少有区域研究在国家一级充分阐明了土壤中农药残留(PRS)的特征以及对生态系统和人类健康的相关风险。因此,本研究旨在编制2006年至2020年中国PRS数据集,并分析PRS与环境之间的相互作用和影响。中国PRS的平均浓度为243.96μg/kg,低于欧美和其他国家的水平。这项研究表明,中国的PRS主要来源于有机氯农药残留,DDT和HCHs是重要的贡献者。尽管中国东南部的农药施用强度很高,PRS浓度与东北部相当,由于环境因素有利于东南部的农药降解。遗留和使用中的农药都是通过地表径流或气流运输的,导致它们在长江下游流域土壤或秦岭山前土壤中积累,分别。中国PRS的平均土壤环境承载力为-69.5kg。中国PRS的生态风险主要处于可忽略的水平。PRS对成人(4.6×10-4)和儿童(6×10-4)的致癌风险略高于可容忍阈值(10-5)。
    The widespread application of pesticides in China has led to the accumulation of residues in soil. However, few regional studies have fully elucidated the characteristics of pesticide residues in soil (PRS) and the associated risks to the ecosystem and human health on a national level. Therefore, this study aims to compile a dataset on PRS in China from 2006 to 2020 and analyze the interactions and impacts between PRS and the environment. The average concentration of PRS in China was 243.96 μg/kg which was lower than the levels reported in Euro-Americans and other nations. This study revealed PRS in China predominantly originates from organochlorine pesticide residues, with DDTs and HCHs being significant contributors. Despite the high intensity of pesticide application in the Southeast China, PRS concentrations were comparable to those in the Northeast, due to environmental factors that favor pesticide degradation in the Southeast. Both legacy and in-use pesticides were transported by surface runoff or air current, resulting in their accumulation in soil of the lower Yangtze River basin or the piedmont soil of Qinling Mountains, respectively. The average soil environment carrying capacity of PRS in China was -69.5 kg. The ecological risk contributed by PRS in China was mainly at a negligible level. Carcinogenic risks of PRS to adults (4.6 ×10-4) and children (6 ×10-4) exceeded the tolerable thresholds (10-5) by a small margin.
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  • 文章类型: Journal Article
    快速的城市化带动了我国智能交通的发展。随着主动安全技术的发展,自动主动安全系统的集成受到越来越多的关注,以实现从功能到全天候智能驾驶的过渡。在这个转变过程中,汽车发展的目标变得明确:自动驾驶汽车。根据《中国自主汽车产业发展预测与战略投资规划分析报告》,目前,中国智能自动驾驶汽车的发展规模超出市场预期。考虑到利用自动驾驶汽车满足城市交通(运输乘客)需求的研究有限,这项研究调查了自动驾驶汽车如何影响特定地区的交通需求,使用交通建模。它研究了自动驾驶汽车在各种场景中的不同渗透率如何影响具有恒定交通需求的道路网络的效率。此外,这项研究还使用构建的NL模型预测了选定地区通勤交通需求的未来变化。结果旨在模拟自动驾驶汽车的交付,以满足该地区的运输需求。
    Rapid urbanization has led to the development of intelligent transport in China. As active safety technology evolves, the integration of autonomous active safety systems is receiving increasing attention to enable the transition from functional to all-weather intelligent driving. In this process of transformation, the goal of automobile development becomes clear: autonomous vehicles. According to the Report on Development Forecast and Strategic Investment Planning Analysis of China\'s autonomous vehicle industry, at present, the development scale of China\'s intelligent autonomous vehicles has exceeded market expectations. Considering limited research on utilizing autonomous vehicles to meet the needs of urban transportation (transporting passengers), this study investigates how autonomous vehicles affect traffic demand in specific areas, using traffic modeling. It examines how different penetration rates of autonomous vehicles in various scenarios impact the efficiency of road networks with constant traffic demand. In addition, this study also predicts future changes in commuter traffic demand in selected regions using a constructed NL model. The results aim to simulate the delivery of autonomous vehicles to meet the transportation needs of the region.
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  • 文章类型: Journal Article
    交通网络的设计通常是在将大都市地区划分为社区的基础上进行的。随着规模的结合,人口密度,以及每个社区的旅行特点,可以更精确地确定交通路线和站点,以满足每个社区内居民的出行需求以及社区之间的交通联系。要准确划分城市社区,在经典Deepwalk模型的基础上改进了原有的词向量抽样方法,提出了一种随机游走(RW)算法,其中采样用广义旅行成本和改进的Logit模型进行了修改。利用K-means算法实现城市空间社区检测,建立F-Deepwalk模型。以基础路网为例,实验结果表明,Deepwalk模型,考虑了居民的广义出行成本,具有更高的轮廓系数,模型的性能随着随机游走长度的减少而提高。同时,以石家庄市轨道交通线网为例,进一步验证了模型的准确性。
    The design of transportation networks is generally performed on the basis of the division of a metropolitan region into communities. With the combination of the scale, population density, and travel characteristics of each community, the transportation routes and stations can be more precisely determined to meet the travel demand of residents within each of the communities as well as the transportation links among communities. To accurately divide urban communities, the original word vector sampling method is improved on the classic Deepwalk model, proposing a Random Walk (RW) algorithm in which the sampling is modified with the generalized travel cost and improved logit model. Urban spatial community detection is realized with the K-means algorithm, building the F-Deepwalk model. Using the basic road network as an example, the experimental results show that the Deepwalk model, which considers the generalized travel cost of residents, has a higher profile coefficient, and the performance of the model improves with the reduction of random walk length. At the same time, taking the Shijiazhuang urban rail transit network as an example, the accuracy of the model is further verified.
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  • 文章类型: Journal Article
    细菌生物膜,尤其是那些由病原体形成的,对人类健康的影响越来越大。细菌胞外囊泡(bEV),细菌释放的一种球形膜结构,不仅被报道为生物膜基质的组成部分,而且在生物膜生命周期中起着不可忽视的作用。然而,对生物膜中bEV功能的全面概述仍然难以捉摸。在这次审查中,我们总结了BEV的生物发生和特征,并巩固有关其在生物膜生命周期中的功能和拟议机制的现有文献。此外,我们强调了生物膜治疗中与囊泡干扰相关的艰巨挑战。这篇综述的主要目的是提高人们对bEV在生物膜生命周期中的功能的认识,并为开发新的治疗策略以控制甚至消除细菌生物膜奠定基础。
    Bacterial biofilms, especially those formed by pathogens, have been increasingly impacting human health. Bacterial extracellular vesicle (bEV), a kind of spherical membranous structure released by bacteria, has not only been reported to be a component of the biofilm matrix but also plays a non-negligible role in the biofilm life cycle. Nevertheless, a comprehensive overview of the bEVs functions in biofilms remains elusive. In this review, we summarize the biogenesis and distinctive features characterizing bEVs, and consolidate the current literature on their functions and proposed mechanisms in the biofilm life cycle. Furthermore, we emphasize the formidable challenges associated with vesicle interference in biofilm treatments. The primary objective of this review is to raise awareness regarding the functions of bEVs in the biofilm life cycle and lay the groundwork for the development of novel therapeutic strategies to control or even eliminate bacterial biofilms.
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  • 文章类型: Journal Article
    本研究采用回归不连续设计,系统地考察了共享单车对城市交通拥堵的治理效果,利用北京的城市级数据,上海,2016年至2018年在中国武汉。我们发现,自行车共享服务的引入在短期内显着缓解了交通拥堵。我们的异质性分析表明,共享单车的初步部署主要缓解了城市拥堵,而额外的部署影响有限。Further,机制测试分析表明,共享单车导致这些城市地铁乘客量增加,有效地解释了道路拥堵的减少。这项研究强调了自行车共享服务在缓解城市交通拥堵方面的关键作用,并为加强中国城市的交通管理策略提供了重要的政策见解。
    This study employs a regression discontinuity design to systematically examine the governance effect of bike-sharing on urban traffic congestion, utilizing city-level data from Beijing, Shanghai, and Wuhan in China between 2016 and 2018. We discover that the introduction of bike-sharing services significantly mitigates traffic congestion in the short term. Our heterogeneity analysis reveals that the initial deployment of shared bicycles primarily alleviates urban congestion, while additional deployments have a limited impact. Further, mechanism test analysis demonstrates that bike-sharing leads to increased metro ridership in these cities, effectively explaining the reduction in road congestion. This study underscores the pivotal role of bike-sharing services in easing urban traffic congestion and provides vital policy insights for enhancing traffic management strategies in Chinese cities.
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  • 文章类型: Journal Article
    “一带一路”倡议(BRI)是历史上最雄心勃勃的基础设施项目。以投资规模为标志,跨越大陆和国家的广泛地理影响,以及从道路到数字网络的各种项目。虽然BRI的环境可持续性引起了人们的关注,这些项目中使用的建筑材料的影响被忽视了,尤其是在发展中国家。这里,我们通过整合来绘制和解释BRI中体现的材料,第一次,官方政府项目报告,地理信息,和材料流分析。我们按材料类型确定和分析每个项目中的BRI材料库存,国家,regions,和部门。从2008年到2023年,全球540个“一带一路”倡议项目中积累了3.28亿吨建筑材料,主要在亚洲和非洲。骨料(沙子和砾石)占最大份额(82%),其次是水泥,钢,和其他材料。大多数材料用于交通基础设施。我们的工作进一步强调了此类可持续性评估的数据质量方面的一些局限性。通过阐明BRI项目对全球原材料使用的重大影响,这项研究为从倡议的角度进一步调查BRI和材料库存-流量关系的环境影响奠定了基础。
    The Belt and Road Initiative (BRI) stands as the most ambitious infrastructure project in history, marked by its scale of investment, extensive geographical reach across continents and countries, and a diverse array of projects from roads to digital networks. While the BRI\'s environmental sustainability has raised concerns, the impacts of construction materials used in these projects have been overlooked, especially in developing countries. Here, we map and account for the materials embodied in the BRI by integrating, for the first time, official governmental project reports, geographical information, and material flow analysis. We pinpoint and analyze the BRI material stocks in each individual project by material types, countries, regions, and sectors. Between 2008 and 2023, 328 million tons of construction materials have accumulated in 540 BRI projects around the world, mostly in Asia and Africa. Aggregates (sand and gravel) constitute the largest share (82%), followed by cement, steel, and other materials. Most of the materials are used in transportation infrastructure. Our work further highlights some limitations in terms of data quality for such sustainability assessments. By shedding light on the significant impact of BRI projects on raw material usage across the globe, this study sets the stage for further investigations into environmental impacts of BRI and material stock-flow-nexus from perspective of an initiative.
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  • 文章类型: Journal Article
    虽然已知大气微塑料可以长距离运输,他们的停留时间和运输过程缺乏清晰度。这项研究利用了天然放射性核素7Be,210Pb,和210Po探索天津大气微塑料的运输,中国北方的一个沿海城市。一年内,微塑料的浓度范围为0.03至0.13个m-3颗粒。冬季微塑料碎片的比例明显高于其他季节,秋季和冬季的中值微塑料尺寸大于春季和夏季的微塑料尺寸。大气微塑料表面粗糙,表现出不规则的孔隙和多个凹陷和裂缝。微塑料在4月和8月经历了与高层大气的垂直混合,并在7月受到降雨的影响。大气颗粒物全年停留时间为9.47天至22.85天,平均14.41天。11月大气颗粒物的峰值停留时间可能与煤炭消耗导致的210Po水平增加有关。它们在大气中的长期存在和粗糙的表面允许微塑料充当各种化学污染物的载体,强调与它们在大气中的存在相关的复杂性和潜在风险。
    While atmospheric microplastics are known to be transported over long distances, their residence times and transport processes lack clarity. This study utilized natural radionuclides 7Be, 210Pb, and 210Po to explore the transport of atmospheric microplastics in Tianjin, a coastal city in Northern China. Microplastic concentrations ranged from 0.03 to 0.13 particles m-3 over the course of a year. The proportion of microplastic fragments in winter was significantly higher than that in other seasons, with median microplastic sizes in autumn and winter being larger than those in spring and summer. The atmospheric microplastic surface was rough, exhibiting irregular pores and multiple depressions and cracks. Microplastics experienced vertical mixing with the upper atmosphere in April and August and were influenced by rainfall in July. The residence time of atmospheric particles ranged from 9.47 to 22.85 days throughout the year, with an average of 14.41 days. The peak residence time of atmospheric particulates in November may be correlated with increased 210Po levels from coal consumption. Their prolonged atmospheric presence and rough surface allow microplastics to act as carriers for various chemical pollutants, underscoring the complexity and potential risks associated with their presence in the atmosphere.
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