This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network ev...This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network evaluation theories based on road "V/C". In addition, it proposes a set of theoretical and technical methods for the real-time evaluation of traffic flows for entire road networks, and for solving key technical issues, such as real-time data collection and processing in areas with no blind zones, the spatial-temporal dynamic analysis of road network traffic, and the calibration of key performance index thresholds. It also provides new technical tools for the strategic transportation planning and real-time diagnosis of road traffic. The new tools and methodology presented in this paper are validated using a case study in Beijing.展开更多
Diffusion couples,WC/Co-1at.%C,V8C7/Co,and WC/Co-0.3wt.%V8C7 were constructed and annealed at temperatures ranging from 1100 to 1300℃. The concentration profile of V and W atoms in these couples were measured by EPMA...Diffusion couples,WC/Co-1at.%C,V8C7/Co,and WC/Co-0.3wt.%V8C7 were constructed and annealed at temperatures ranging from 1100 to 1300℃. The concentration profile of V and W atoms in these couples were measured by EPMA. Aided by Thermo-calc ＆ DICTRA software package,the concentration profiles of W and V in established diffusion couples were calculated by the moving boundary model according to revised dynamic parameters and MOB database,respectively. Then the concentration profile of W in Co binder during sintering WC-Co cemented carbide was simulated by the Cell model. It can provide reference for composition and sintering process design of cemented carbides with high performance. Meanwhile,the validity of revised dynamic parameters of the W-C-Co-V system is verified by the comparison of experimental and simulated results.展开更多
基金"973"National Key Basic Research & Development Program "Research of the Basic Scientific Issues in the Traffic Congestion Bottlenecks of Big Cities"( No. 2006CB705500)Beijing Science & Technology Program "Research of the New Data Collection Technologies for Transportation Management " (No.D101100049710004)Beijing Science & Technology Program "Research of the Demonstration Platform for the In-tegrated Dynamic Operation Analysis of City Road Networks"(No. D07050600440704)
文摘This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network evaluation theories based on road "V/C". In addition, it proposes a set of theoretical and technical methods for the real-time evaluation of traffic flows for entire road networks, and for solving key technical issues, such as real-time data collection and processing in areas with no blind zones, the spatial-temporal dynamic analysis of road network traffic, and the calibration of key performance index thresholds. It also provides new technical tools for the strategic transportation planning and real-time diagnosis of road traffic. The new tools and methodology presented in this paper are validated using a case study in Beijing.
基金the National Natural Science Foundation of China (No. 50471101)the Flan-ders-China Bilateral Project BIL 02/04.
文摘Diffusion couples,WC/Co-1at.%C,V8C7/Co,and WC/Co-0.3wt.%V8C7 were constructed and annealed at temperatures ranging from 1100 to 1300℃. The concentration profile of V and W atoms in these couples were measured by EPMA. Aided by Thermo-calc ＆ DICTRA software package,the concentration profiles of W and V in established diffusion couples were calculated by the moving boundary model according to revised dynamic parameters and MOB database,respectively. Then the concentration profile of W in Co binder during sintering WC-Co cemented carbide was simulated by the Cell model. It can provide reference for composition and sintering process design of cemented carbides with high performance. Meanwhile,the validity of revised dynamic parameters of the W-C-Co-V system is verified by the comparison of experimental and simulated results.
