检索结果-南通市图书馆

Structure and evolution of the submarine cable network of Chinese mainland

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2022年第5期32卷 932-956页

作者： XIE Yongshun wang chengjin HUANG Jie Institute of Geographic Sciences and Natural Resources Research CASBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China

Submarine cable network is one of the most important connectivity infrastructures in the digital *** the past 20 years,the submarine cable network of Chinese mainland has formed a complex connectivity *** paper focuses on exploring the structure and evolution of the submarine cable network of Chinese *** results show that the evolution can be divided into four stages:an initial stage(1993-1998),a developmental stage(1999-2002),a stagnation stage(2003-2015)and an accelerated stage(2016-2018).The connectivity structure can be analyzed at micro,meso and macro ***,the connectivity increased significantly overall,but showed significant differences in *** the microscale,the landing cities were characterized by“extensive but low,exclusive and high”;for the mesoscale,the connectivity of countries or regions was characterized by“distance attenuation”as a whole,but,in part,by a“regional identity”;for the macroscale,intercontinental connectivity differences have been *** hierarchy has been upgraded from a“3 system”to a“2+3 system”.Finally,this paper discusses the interaction between submarine cable network construction and international relations,and puts forward policy suggestions for China’s submarine cable construction.

关键词： submarine cable network structure connectivity evolution Chinese mainland

Port Integration in China: Temporal Pathways, Spatial Patterns and Dynamics

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2015年第5期25卷 612-628页

作者： wang chengjin César DUCRUET wang Wei Key Laboratory of Regional Sustainable Development Modeling Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences French National Centre for Scientific Research (CNRS) UMR 8504 Géographie-citésParis F-75006 France University of Chinese Academy of Sciences

Over the past two decades, numerous ports located in China have participated in port integration strategies, thus influencing the entire port system. The current research is initiated in order to examine the nature of port integration in China, including associated temporal pathways, spatial patterns and dynamics. Results indicate that port integration in China has been characterized by a significant increase at the turn of the 21 st century, comprising thirteen distinguishable pathways typified by differing dynamics, particularly between the northern and southern ports. Pathways were found to include 44 seaports and river ports, chiefly concentrated in the Bohai Rim, Yangtze(Changjiang) River Delta, Beibu Gulf and the southeastern Fujian, thus representing significant spatial regions. Categorically larger seaports have become the primary beneficiaries of port integration. Integration cases were divided into four categories based upon quantified dynamic magnitude including the government-driven mode, market-driven mode, government/market-driven mode and strategic alliance, and into five further categories based upon spatial extent including port internal integration, jurisdictional port integration, port integration across neighbor region, regional port integration and hub-feeder port integration. Results suggest that several factors have effectively driven port integration in China, including legislative tools and spatial planning, optimization of shoreline resources and port functionality, and port competition with the same hinterland.

关键词： port integration integration mode integration pathway integration dynamics China

Design, Characterization, and 3D Printing of Cardiovascular Stents with Zero Poisson’s Ratio in Longitudinal Deformation

在线全文

学校读者我要写书评

暂无评论

Engineering 2021年第7期7卷 979-990页

作者： chengjin wang Lei Zhang Yongcong Fang Wei Sun Biomanufacturing Center Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing Beijing 100084China “Biomanufacturing and Engineering Living Systems”Innovation International Talents Base(111 Base) Beijing 100084China Department of Mechanical Engineering Drexel UniversityPhiladelphiaPA 19104USA

Inherent drawbacks associated with drug-eluting stents have prompted the development of bioresorbable cardiovascular *** manufacturing(3-dimentional(3D)printing)has been widely applied in medical *** this study,we develop a novel screw extrusion-based 3D printing system with a new designed mini-screw extruder to fabricate stents.A stent with a zero Poisson’s ratio(ZPR)structure is designed,and a preliminary monofilament test is conducted to investigate appropriate fabrication parameters.3D-printed stents with different geometric structures are fabricated and analyzed by observation of the surface *** evaluation of the mechanical properties and a preliminary biological evaluation of 3D-printed stents with different parameters are carried *** conclusion,the screw extrusion-based 3D printing system shows potential for customizable stent fabrication.

关键词： Additive manufacturing 3D printing Screw extrusion Cardiovascular stent Zero Poisson’s ratio

ndustrial eco-efficiency and its spatial-temporal differentiation 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

Frontiers of Environmental Science & Engineering 2012年第4期6卷 559-568页

作者： Wei YANG Fengjun JIN chengjin wang Chen LV Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Regional Sustainable Development Modeling Chinese Academy of SciencesBeijing 100101China School of Environment Tsinghua UniversityBeijing 100084China

The aim of this paper is to study the spatialtemporal differentiation of industrial eco-efficiency in China. Using methods based on the data envelopment analysis （DEA） model and exploratory spatial data analysis （ESDA） and data from 1985, 1995, 2005, and 2008 of 30 provinces in China, the spatial-temporal pattern changes in industrial eco-efficiency are discussed. The results show that： first, the patterns of industrial eco-efficiency are dominated by clustering of relatively low efficiency provinces; second, spatial relationships between the industrial eco-efficiencies of different provinces changed slightly throughout the period and the provinces persistently exhibit spatial concentration of relatively low industrial eco-efficiency; finally, there is an obvious trend in the polarization of industrial eco-efficiency, i.e., the higher level spatial units are concentrated in eastern China, and the lower level spatial units are mainly in western and central China. （ESDA）

关键词： industrial eco-efficiency data envelopment analysis (DEA) model exploratory spatial data analysis

Transportation Development Transition 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

Chinese Geographical Science 2012年第3期22卷 319-333页

作者： JIN Fengjun DING Jinxue wang Jiao'e LIU Dong wang chengjin Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Transport Planning and Research Institute Ministry of Transport Beijing 100028 China

Scientific development is an invaluable asset to a *** and development modes should be carried out based on scientific findings not only in industry,but also in transportation infrastructure *** an integrated transportation system,which is in line with the national requirements of China and supports sustainable socio-economic development,is a key strategic issue related to building a moderately prosperous society and achieving realistic goals of a medium-level developed *** on a systematic review of the advances in China's transportation infrastructure over the last 60 years,this paper explores the main drivers of transportation development,including national policy,transportation structure,investment efficiency,and technological *** shows that China's comprehensive transportation infrastructure construction since 1949 can be divided into five stages initiated by these drivers,which correspond to four transition modes:policy transition,structural transition,efficiency transition,and technology *** transition path of China's transportation development shows that the dominant factors have changed,and the interval for each transition has *** the implementation of the '12th Five-Year Plan',China's transportation infrastructure construction is showing some new characteristics and facing a new development ***,this paper analyzes the trends in transportation development in China and concludes that technological innovation will be the main driving force to increase the transportation supply and service area in the future.

关键词： transportation infrastructure development transition integrated transportation system impact factor

A critical literature review of bioretention research for stormwater management in cold climate and future research recommendations

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2017年第4期11卷 23-37页

作者： Hannah Kratky Zhan Li Yijun Chen chengjin wang Xiangfei Li Tong Yu Department of Civil and Environmental Engineering University of Alberta Edmonton Alberta T6G 1H9 Canada City Planning City of Edmonton Edmonton Alberta T5J 0J4 Canada

Bioretention is a popular best management practice of low impact development that el/ecUvely restores urban hydrologic characteristics to those ofpredevelopment and improves water quality prior to conveyance to surface waters. This is achieved by utilizing an engineered system containing a surface layer of mulch, a thick soil media often amended with a variety of materials to improve water oualitv, a variety of vegetation, and underdrains, depending on the surrounding soil *** systems have been studied quite extensively for warm climate applications, but ctata strongly supporting their long-tema efficacy and application in cold climates is sparse. Although it is apparent that biorelention is an effective stormwater management system, its design in cold climate needs further research. Existing cold climate research has shown that coarser media is required to prevent concrete frost from forming. For spring, summer and fall seasons, if sufficient permeability exists to drain the system prior to freezing, peak flow and volume reduction can be maintained. Additionally. contaminants that are removed via filtration are also not impacted by cold climates. In contrary, dissolved contaminants, nutrients, and organics are significantly more variable in their ability to be removed or degraded via bioretention in colder temperatures. Winter road maintenance salts have been shown to negatively impact the removal of some contaminants and positively impact others, while their effects on properly selected vegetation or bacteria health are also not well understood. Research in these water quality aspects has been inconsistent and therefore requires further study.

关键词： Bioretention Cold climate Low impact development Stormwater

Physical modeling of long-term dynamic characteristics of the subgrade for medium-low-speed maglevs

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

Railway Engineering Science 2023年第3期31卷 293-308页

作者： Minqi Dong Wubin wang chengjin wang Zhichao Huang Zhaofeng Ding Zhixing Deng Qian Su School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China National Engineering Research Center of Geological Disaster Prevention Technology in Land Transportation Southwest Jiaotong UniversityChengdu 611756China China Railway Maglev Transportation Investment Construction China Railway Construction Corporation LimitedWuhan 430000China

To investigate the dynamic characteristics and long-term dynamic stability of the new subgrade structure of medium-low-speed(MLS)maglevs,cyclic vibration tests were performed under natural and rainfall conditions,and the dynamic response of the subgrade structure was *** dynamic response attenuation characteristics along the depth direction of the subgrade were compared,and the distribution characteristics of the dynamic stress on the surface of the subgrade along the longitudinal direction of the line were *** critical dynamic stress and cumulative deformation were used as indicators to evaluate the long-term dynamic stability of the *** show that water has a certain effect on the dynamic characteristics of the subgrade,and the dynamic stress and acceleration increase with the water *** the dowel steel structure set between the rail-bearing beams,stress concentration at the end of the loaded beam can be prevented,and the diffusion distance of the dynamic stress along the longitudinal direction *** dynamic stress measured in the subgrade bed range is less than 1/5 of the critical dynamic *** postconstruction settlement of the subgrade after similarity ratio conversion is 3.94 mm and 7.72 mm under natural and rainfall conditions,respectively,and both values are less than the 30 mm limit,indicating that the MLS maglev subgrade structure has good long-term dynamic stability.

关键词： Medium-low-speed maglev Subgrade Dynamic characteristics Long-term dynamic stability Model test

Evolution, accessibility and dynamics of road networks in China from 1600 BC to 1900 AD

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2015年第4期25卷 451-484页

作者： wang chengjin DUCRUET Cesar wang Wei Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China French National Centre for Scientific Research (CNRS) UMR 8504 G6ographie-cites F-75006 ParisFrance University of Chinese Academy of Sciences Beijing 100049 China

Before the emergence of modern modes of transport, the traditional road infra structure was the major historical means of carrying out nationwide socioeconomic exchange However, the history of transport infrastructure has received little attention from researchers. Given this background, the work reported here examined the longterm development of transport networks in China. The national road network was selected for study and the 3500 years from 1600 BC to 1900 AD was chosen as the study period. Indicators were designed for the maturity level of road networks and an accessibility model was developed for the paths of the shortest distance. The evolution of the road network in China since the Shang Dynasty （1600 BC） was described and its major features were summarized to reveal longterm regu larities. The maturity level of the road network and its accessibility was assessed and regions with good and poor networks were identified. The relationship between China＇s natural, social and economic systems and the road network were discussed. Our analysis shows that the road network in China has a number of longterm regularities. The continuously expanding road network follows a path of inland expansion especially towards the border areas. How ever, its coverage and accessibility are characterized by a coreperipheral configuration, which has close relationships with, not only the natural conditions, but also national defense and warfare. The centralization of national power, national land governance, postal transport, the transport of specialized cargos, and international trade are also related to the develop ment of the road network. This research draws attention to the evolving regularities of trans port networks.

关键词： China road networks historical evolution accessibility dynamic mechanisms

Peripheral Challenge in Container Port System:A Case Study of Pearl River Delta

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2012年第1期22卷 97-108页

作者： wang chengjin wang Jiao'e Cesar DUCRUET Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China French National Centre for Scientific Research UMR 8504 Geographie-citesParis 75006France

The growth of peripheral ports to dominant hubs has been well documented in North America and Europe,and has led to the elaboration of several theoretical ***,although changes in containerization growth have been taking place in the South and East Asia in recent years,particularly in China,only a few studies have fo-cused on this *** Pearl(Zhujiang) River Delta(PRD) has a typical port system with hub and peripheral ports,and provides an excellent case for studying the Peripheral *** paper introduces the theoretical evidence of the Hayuth model and analyzes the evolution of the container port system in the PRD with five phases:1) phase I:preconditions for change and phase II:initial container port development in the 1970s and early 1980s;2) phase III:diffusion,consolidation,and port concentration in the middle and late 1980s;3) phase IV:the load center in the 1990s;and(4) phase V:the Peripheral Challenge since the late *** results illustrate that the Shenzhen port presents mounting challenges to the Hong Kong port,descending from a transshipment hub of China to a regional load center of Southeast ***,this paper explores five points that have led to the evolution of the port system in the PRD:1) competition in the regional port systems;2) different interested parties;3) shift of investment strategies of in-ternational terminal operators;4) integration of shipping networks and reorganization of carriers;and 5) cost-based competition.

关键词： Hayuth model peripheral challenge Pearl River Delta (PRD) container shipping