检索结果-南通市图书馆

Ecological impact assessment method of highways in Tibetan Plateau:A Case study of Gonghe-Yushu Expressway

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2020年第8期17卷 1916-1930页

作者： YANG Hong-zhi WANG Zhen-feng DAI Qing-miao school of highway Chang'an UniversityXi'an 710064China China Design Group Co. Ltd.Nanjing 210000China

In recent years,the ecological environment along highways in Tibetan Plateau has been severely affected due to the rapid construction of *** order to solve the problems of multiple indicators and inconsistent criteria in the ecological impact assessment of highways,and to scientifically screen assessment indicators,the paper proposes a multi-round indicator screening method,which combines literature analysis,expert rating,and statistical *** on this screening method,normalized difference vegetation index,land surface temperature,elevation,and normalized difference soil index are screened *** with multiple linear regression,an ecological impact assessment model is established and applied to ecological impact assessment of Gonghe-Yushu *** results show that the expressway construction is the first driving force for the deterioration of the ecological environment along the roadside,and its interference range on the desert grassland ecosystem is greater than that on the agroforestry *** ecological environment within 150 m on both sides of the expressway should be protected.

关键词： highway Tibetan Plateau Ecological impact assessment Multi-round indicator screening method Contribution index cyclic analysis Multiple linear regression

Durability of Asphalt Mixture in Different Corrosion Solution

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2011年第6期26卷 1200-1204页

作者：陈拴发关博文 Key Laboratory for Special Area highway Engineering of Ministry of Education Chang’an University school of Materials Science and Engineering Chang’an University

The corrosion to asphalt mixture under different kinds of corrosion solution, such as pH=2 solution, pH=12 solution, pH = 12 solution and 10% Na2SO4 solution, was studied. The performance attenuation of asphalt mixture was analyzed under the normal environment and the freeze-thaw environment, and the analysis was given on the sensitivity of the test results to the evaluation index. The experimental results show that the performance of asphalt mixture is attenuated faster under the acidic solution, alkaline solution and sulfate solution. Corrosion factor Kc, freeze-thaw corrosion factor Kf, and freeze-thaw effect factor Kfc are proposed to evaluate asphalt mixture resistance to corrosion in different kinds of corrosion solution. The values of Kc and Kfc decrease with the increasing of corrosion time. The change rule of Kf show that the rate of corrosion is decreased by the action of freeze-thaw in acidic solution and in alkaline solution, but is increased by the action of freeze-thaw in sulfate solution. The microscopic analysis indicates that acid solution reacts with aggregate of asphalt mixture, alkaline solution reacts with asphalt cement of asphalt mixture, the surface tension of sulfate solution and crystallization of sulfate are the main reasons which weak the performance of asphalt mixture.

关键词： asphalt mixture corrosion damage corrosion mechanism corrosion evaluation

A new targeted on-ramp control approach considering both efficiency and equity

在线全文

学校读者我要写书评

暂无评论

Transportation Safety and Environment 2024年第3期6卷 85-95页

作者： Shengnan Li Minglun Li Jianjun Dai Pu Wang school of Traffic and Transportation Engineering Central South UniversityChangsha 410075HunanChina Hunan Communications Research Institute Co. LtdChangsha 410015HunanChina

On-ramp control is an effective approach for alleviating traffic congestion on ***,there is still a lack of on-ramp control approaches applicable to large regional highway ***,we develop a targeted on-ramp control approach applicable to regional highway networks by taking advantage of the vehicle source information,which pinpoints the on-ramps contributing major traffic flow to the highway ***,a combined and tunable controlling index is proposed to enhance the equity of the generated traffic control *** proposed on-ramp control approach is validated on an actual large highway network using actual travel demand *** indicate that the proposed approach can well mitigate the traffic congestion of highway bottleneck while at the same time enhancing the equity and practicability of the generated traffic control scheme.

关键词： on-ramp control vehicle source traffic congestion equity

Application of modern timber structure in short and medium span bridges in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2014年第1期1卷 72-80页

作者： Meizhen Fu Yongjian Liu Na Li Zhiwei Zhang Enzo Siviero school of highway Chang'an University Department of Architectural Construction IUAV University of Venice

A series of problems about Chinese bridges with short and medium span recent years were analyzed in this paper. The necessity and feasibility of modern timber structure applied in short and medium span bridges in China were also put forward. The results showed that the short and medium span bridges had many problems, such as monotonous structural forms, seri- ous environmental pollution, multiple bridge defects and difficulty in maintenance. With the development of connection and maintenance technology of modern timber structure and its ad- vantages of light self-weight, environmental coordination, high carrying capacity, excellent durability and abundant structural forms, it was necessary and feasible to apply modern timber structure in short and medium span bridges in China. More emphasis on the construction of modern timber structure should be conducted to expand its application scopes and improve the construction proportion of short and medium span timber bridges.

关键词： short and medium span bridges timber structure modern timber bridge application scope

Extraction of Content-Free Basal Image and Its Application in Face Recognition

在线全文

学校读者我要写书评

暂无评论

Extraction of Content-Free Basal Image and Its Application i...

A Design of Single-Switch Two-Stage DC-DC Converters With PWM And PFM for Off-Grid Solar Power System

第32届中国控制与决策会议

作者： Lan Zhangli Shen Dexing Tang Ranran Chongqing Jiaotong University School of information science and engineering Chongqing highway bureau

ISBN: (数字)9781728158556

ISBN: (纸本)9781728158563

As a typical signal,an image can be composed of a series of basic signals,which are called basal *** order to find the basic signals of a group of reconfigurable arbitrary images and optimize the face recognition algorithm,a feature-based basal image extraction method is proposed and applied to face recognition,so that the basal image can be extracted from any set of images and the performance of face recognition algorithm to local changes such as illumination and expression can be *** extraction algorithm is used to decompose a series of basal images from the training set image,the algorithm flow of basal image decomposition and extraction is expounded,the projection coefficient is obtained by projecting the face image into the space constituted by the basal image,the distance between the test sample and the training sample coefficient matrix is calculated,and the minimum distance classifier is used for *** experimental results show that the basal image obtained from any image set can be used for face recognition,and the basal image have content *** the same time,this method is better than the traditional feature face recognition method in light,expression,wearing accessories and other local changes.

关键词： Face recognition Feature extraction Characteristic matrix Basal image Content-free

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2017年第3期3卷 44-51页

作者： Junkai Zhao Herbert H.C.Iu Tyrone Fernando school of Electrical Electronic and Computer EngineeringThe University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

In this paper,a single-switch two-stage DC-DC conversion circuit is proposed for an off-grid solar power application.A photovoltaic(PV)panel powers the load and a storage unit(battery)via the proposed *** battery is designed to balance the supply and the demand of power under different irradiation *** on conventional cascaded DC-DC converters,the proposed design is developed with the single switch technique reducing size,cost and power *** control scheme in this design is pulse width modulation(PWM)with pulse frequency modulation(PFM).The PWM module is similar to conventional design except its ramp signal with a variable frequency is provided by a resettable *** a result,the PWM and PFM modules regulate the two stages of the proposed circuit separately with the same switching control *** this paper,the modes of operation of the circuit are discussed as well as the control *** design process is described along with the circuit analysis and comparisons with conventional design are made as well.A prototype has been built to verify the proposed circuit with simulation and experimental results.

关键词： Single-switch technique photovoltaic power system off-grid solar system DC-DC conversion resettable integrator pulse frequency modulation(PWM) pulse width modulation(PFM)

Investigation of internal phases of linear SBS modified bitumen at the nanoscale using AFM PF-QNM

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2023年第3期10卷 399-412页

作者： Chengwei Xing Liping Liu Wei Jiang Jinhuan Shan Jingjing Xiao Dongdong Yuan Wangjie Wu Key Laboratory of Special Area highway Engineering of Ministry of Education Chang'an UniversityXi'an 710064China school of highway Chang'an UniversityXi'an 710064China Key Laboratory of Road and Traffic Engineering of Ministry of Education Tongji UniversityShanghai 201804China school of Civil Engineering Chang'an UniversityXi'an 710064China

Currently,few studies explore the internal phases of styrene-butadiene-styrene(SBS)modified bitumen at the nanoscale,though the surface phases of SBS modified bitumen have been deeply understood through a lot of *** present study uses the atomic force microscopy(AFM)peak force quantitative nanomechanical mode(PF-QNM)to investigate the nanomechanical properties of the interior of linear SBS modified bitumen and corresponding mastics at the ***,the suitable experimental methods for the interior of bitumen and mastics are ***,the phase relationship between surfaces and interiors of linear SBS modified bitumen is determined by analyzing nanomechanical *** this basis,in comparison with the internal phases of base bitumen,the effect of modifiers on phases is deeply ***,the internal phases of linear SBS modified bituminous mastics are further *** results reveal that the interior of linear SBS modified bitumen only has two phases,which form in a manner like periphase and paraphase on the *** contrast to base bitumen,linear SBS modified bitumen does not create new phases and change the properties of original phases in the interior,but affects the proportion of A-phase and B-phase and presents the ***,due to the influence of preparation methods,only the bitumen area away from the fillers can be imaged by AFM *** can be found that the addition of mineral fillers also slightly changes the internal phase distribution of linear SBS modified bitumen,while the effect is less than that of fillers on base bitumen.

关键词： Road engineering SBS modified bitumen Internal phase AFM PF-QNM

Review on evolution and evaluation of asphalt pavement structures and materials

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2020年第5期7卷 573-599页

作者： Yu Liu Peifeng Su Miaomiao Li Zhanping You Mohan Zhao school of highway Chang'an UniversityXi'an 710064China Department of Civil and Environmental Engineering Michigan Technological UniversityHoughtonMI 49931USA

The purpose of this study was to summarize the wide-range literatures on asphalt pavements, explore the evolution of road pavements, analyze typical asphalt pavement structures, highlight current trends in research and industry, and to recommend future areas of research and development. In this research, road pavement evolution was explored from the earliest roads to the modern pavements. A new method was recommended to categorize asphalt pavement materials into the three large families which may be further sub-divided according to their mechanical parameters. A unified asphalt pavement classification(UAPC) method was proposed and the worldwide asphalt pavements could be divided into six types through the new method. Based o n the UAPC method, 1087 asphalt pavement structures were classified and analyzed to explore the asphalt thickness variation. In order to evaluate asphalt pavement performance, the Chinese design specification was employed for analyzing lives of 29 high-volume pavements and 28 low-volume pavements. Through this research, it was found that:(1) in the past 100 years, asphalt pavement materials and structures had been becoming more and more strong;(2) asphalt layer thicknesses were various from 5 to 60 cm and the overall pavement thicknesses were various from 28 to 160 cm;(3) the long-life pavements in the other countries may become"shorter-life" pavements according to the prediction based on the Chinese specification.

关键词： Road engineering Asphalt pavement Materials classification Pavement life Structural classification Road evolution

Hysteresis of Dam Slope Safety Factor under Water Level Fluctuations Based on the LEM Coupled with FEM Method

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2022年第11期133卷 351-375页

作者： Guodong Liu Zhijun Zhou Shiqiang Xu Wenjing Mi school of highway Chang’an UniversityXi’an710046China College of Urban Rural Planning and Architectural EngineeringShangluo UniversityShangluo726000China

Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam *** required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil-water characteristic curve(SWCC)on the stability of the upstream dam *** results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC,which would be more evident at higher water *** safety factor of the upstream dam slope initially decreased and then increased for the most dangerous water level as the water level rose and *** water level fluctuation rate mainly influenced the initial section of the safety factor variation curve,while the SWCC hysteresis mainly affected the minimum safety factor of the water level *** desorption SWCC is suggested for engineering ***,a quick prediction method is proposed to estimate the safety factor of upstream dam slopes with identical structures.

关键词： Water level SWCC safety factor dam slope hysteresis