155 research outputs found

    Risk Management of Road Engineering Project Based on Analytic Hierarchy Process

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    In the construction process of road engineering, risks are everywhere. To do a good job in the risk management of road engineering projects, finding the risk factors of road engineering projects is an important part of it. This article introduces the characteristics of project risks and the process of risk management. The AHP method is applied to the risk analysis of road engineering projects to realize the ranking of risk factors, the evaluation of the total risk system, and the selection of risk response measures. This article conducts risk evaluation on the project, finds out important risk factors, and effectively controls them. This paper adopts the analytic hierarchy process on the overall risk management of road engineering projects. Finally, it comprehensively considers the systemic and non-systematic risks faced by road engineering, and specifically involves macro policy and economic risks, as well as project initiation and project construction. The risks and capital risks, and other links considered the internal and external factors of the road-engineering project. In this way, the project risk has been comprehensively measured by a combination of qualitative and quantitative methods, and the effective management of the project has been finally realized

    Research on Bridge Structural Health Assessment Based on Finite Element Analysis

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    In view of the content of bridge condition assessment and health monitoring, this paper is based on the finite element simulation analysis. The uncertain finite element model updating method based on sequential optimization strategy is studied, and the uncertain modal parameter data obtained by health monitoring system are applied to upgrade the uncertain finite element model of cable-stayed bridges, which provides a more accurate finite element model for subsequent reliability analysis. Firstly, the finite element dynamic analysis of the main span structure of the bridge is carried out, and the natural frequencies and modes are obtained. Then the measured natural frequencies of the structure are obtained by estimating the power spectrum of the dynamic monitoring data, and the theoretical values are compared with the measured ones. The dynamic characteristics of the modified two-stayed bridge finite element model are verified by the load test results. The results show that the modified finite element model can simulate the dynamic characteristics of the actual structure well. Most of the measured and calculated displacement increments were within the margin of error. The error is within 5%, which can accurately reflect the true stress state of the structure. The uncertainty model based on the sequential optimization strategy is simple and can be applied to the uncertainty of the finite element model of the actual bridge structure

    Study on Modern Bridge Structure Health Monitoring System Based on Damage Identification

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    With the rapid growth of traffic, the loads\u27 design of many existing bridges can no longer meet the current vehicle load requirements, and the structural safety is seriously threatened. To ensure the structural safety of the bridge, it is necessary to monitor the bridge health and establish an early warning mechanism to prevent major accidents. The modern concrete bridge structure health monitoring based on damage identification proposed in this paper carried out principal component analysis of modern concrete bridges, and then this paper used principal component analysis (PCA) to locate the nonlinear damage source of the experimental model, which obtained the following conclusions. The maximum shear stress of the steel beam web is about 80 MPa,and the bulk stress of steel is reached at 7.5 MPa. Furthermore, to reduce the original data\u27s dimensionality, PCA effectively retains the characteristic information of the original data; empirical examples from external factor are presented. The major advantage of applying this framework is that the structural damage identification is simple and reliable with its advantages of dimensionality reduction, noise reduction, and exclusion of out-of-bounds interference factors

    Patterns and Determinants of Antibiotic Use Behaviors among Rural Community Residents in Eastern China

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    Inappropriate antibiotic use may lead to antibiotic resistance, which has become a serious global crisis. Addressing suboptimal antibiotic use in the general population can play a significant role in the fight against antimicrobial resistance. This study aims to describe antibiotic use and sources of acquisition, and to identify factors influencing antibiotic access among rural community residents in Eastern China. A cross-sectional survey was conducted from July to August 2020, and 1494 participants from two villages in Eastern China were enrolled. Information was obtained using face-to-face interviews with a structured electronic questionnaire. Chi-squared and multinominal logistic regression analysis were used to explore possible determinants. In total, 1379 participants were eligible for the analysis. In the past 12 months, nearly half the respondents had taken any antibiotic (48.4%), and this proportion varied across marital status and age group. Two thirds of them (59.9%) obtained antibiotics from medical facilities with a prescription when they last took antibiotics, while 17.7% and 22.4% chose retail pharmacies and other sources, respectively. Multinominal analysis found that a higher proportion obtained antibiotics outside medical facilities among those aged 15 to 44 years, unmarried, non-white collar workers, with more years of education, lower annual household income per capita and lower levels of antibiotic knowledge. The antibiotic use behavior of rural community residents in Eastern China remains suboptimal. Antibiotic use and access behaviors need to be further addressed. Effective antibiotic stewardship in non-medical facility sources and training programs targeted for rural Chinese is warranted in future

    Interfacing with silica boosts the catalysis of copper

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    厦门大学化学化工学院郑南峰教授团队长期致力于研究固体功能材料的表界面化学行为,在分子水平上实现对固体功能材料的化学性能的调控与优化。得益于固体表面物理化学国家重点实验室的多学科合作以及能源材料化学协同创新中心的多单位优势互补,郑南峰教授课题组通过与校内外多个课题组的密切合作,近期在功能材料的可控制备、复杂表界面结构的高分辨表征和表界面过程分子机制的深入理解等方面取得系列重要进展,相关成果近期均在Nature Communications发表。 与厦门大学傅钢、袁友珠教授以及中国科学院物理研究所谷林研究员密切合作,历时五年,在多相催化的金属-载体界面效应研究方面取得重要进展。SiO2被广泛用作工业负载型金属催化剂的载体,多被视为惰性载体,在催化过程中仅起到分散金属的作用。郑南峰教授领衔的合作研究打破这个催化领域的“定式”。他们发现了“惰性”载体SiO2与Cu之间存在可以数量级提升酯基加氢催化性能的活性界面,揭示了相关界面效应的分子作用机制,并应用于指导实用铜催化剂的制备。【Abstract】Metal-support interaction is one of the most important parameters in controlling the catalysis of supported metal catalysts. Silica, a widely used oxide support, has been rarely reported as an effective support to create active metal-support interfaces for promoting catalysis. In this work, by coating Cu microparticles with mesoporous SiO2, we discover that Cu/SiO2 interface creates an exceptional effect to promote catalytic hydrogenation of esters. Both computational and experimental studies reveal that Cu–Hδ− and SiO–Hδ+ species would be formed at the Cu–O–SiOx interface upon H2 dissociation, thus promoting the ester hydrogenation by stablizing the transition states. Based on the proposed catalytic mechanism, encapsulting copper phyllosilicate nanotubes with mesoporous silica followed by hydrogen reduction is developed as an effective method to create a practical Cu nanocatalyst with abundant Cu-O-SiOx interfaces. The catalyst exhibits the best performance in the hydrogenation of dimethyl oxalate to ethylene glycol among all reported Cu catalysts.We thank the National Key R&D Program of China (2017YFA0207302, 2017YFA0207303, 2017YFA0206801), the NNSF of China (21731005, 21420102001, 21721001, 21333008, 21373167, 21573178), and the Fundamental Research Funds for the Central Universities (20720160046) for financial support. 研究工作得到了科技部、国家自然科学基金委和教育部,中科院先导项目,国家重点研发计划,分子反应动力学国家重点实验室开放课题基金等项目的资助

    Impacts of Antibiotic Residues in the Environment on Bacterial Resistance and Human Health in Eastern China: An Interdisciplinary Mixed-Methods Study Protocol

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    Antibiotic resistance is a global health challenge that threatens human and animal lives, especially among low-income and vulnerable populations in less-developed countries. Its multi-factorial nature requires integrated studies on antibiotics and resistant bacteria in humans, animals, and the environment. To achieve a comprehensive understanding of the situation and management of antibiotic use and environmental transmission, this paper describes a study protocol to document human exposure to antibiotics from major direct and indirect sources, and its potential health outcomes. Our mixed-methods approach addresses both microbiological and pathogen genomics, and epidemiological, geospatial, anthropological, and sociological aspects. Implemented in two rural residential areas in two provinces in Eastern China, linked sub-studies assess antibiotic exposure in population cohorts through household surveys, medicine diaries, and biological sampling; identify the types and frequencies of antibiotic resistance genes in humans and food-stock animals; quantify the presence of antibiotic residues and antibiotic resistance genes in the aquatic environment, including wastewater; investigate the drivers and behaviours associated with human and livestock antibiotic use; and analyse the national and local policy context, to propose strategies and systematic measurements for optimising and monitoring antibiotic use. As a multidisciplinary collaboration between institutions in the UK and China, this study will provide an in-depth understanding of the influencing factors and allow comprehensive awareness of the complexity of AMR and antibiotic use in rural Eastern China
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