A longitudinal slope brake model was established for the radius calculation of vertical curve of freeway through analyzing the dynamics of brake-running of vehicles running on the longitudinal slope road section. To s...A longitudinal slope brake model was established for the radius calculation of vertical curve of freeway through analyzing the dynamics of brake-running of vehicles running on the longitudinal slope road section. To satisfy the requirement of sight distance, a relation model was established for the attachment coefficient and the convex vertical curve radius. Using MATLAB simulation technique, the convex vertical curve radius at different attachment conditions was calculated accurately and a three-dimensional figure was drawn to describe the relation between the adhesive coefficient, the driving velocity and the radius of vertical curve. The correlation between the convex vertical curve radius and the adhesive coefficient was further analyzed and compared with National Technical Standards. The suggested radius of vertical curve was then put forward to provide a theoretical platform for the security design of the convex vertical curve.展开更多
In this paper, the dielectric properties of CO2, CO2/air, CO2/O2, CO2/N2, CO2/CF4, CO2/CH4, CO2/He, C02/H2, CO2/NH3 and CO2/CO were investigated based on the Boltzmann equation analysis, in which the reduced critical ...In this paper, the dielectric properties of CO2, CO2/air, CO2/O2, CO2/N2, CO2/CF4, CO2/CH4, CO2/He, C02/H2, CO2/NH3 and CO2/CO were investigated based on the Boltzmann equation analysis, in which the reduced critical electric field strength （E/N）cr of the gases was derived from the calculated electron energy distribution function （EEDF） by solv- ing the Boltzmann transport equation. In this work, it should be noted that the fundamental data were carefully selected by the published experimental results and calculations to ensure the validity of the calculation. The results indicate that if He, H2, N2 and CH4, in which there axe high ionization coefficients or a lack of attachment reactions, are added into CO2, the dielectric properties will decrease. On the other hand, air, O2, NH3 and CFa （ranked in terms of （E/N）cr value in increasing order） have the potential to improve the dielectric property of CO2 at room temperature.展开更多
基金the National Key Technology R&D Program for the 11thFive-year Plan (Grant No.2006BAJ18B01)
文摘A longitudinal slope brake model was established for the radius calculation of vertical curve of freeway through analyzing the dynamics of brake-running of vehicles running on the longitudinal slope road section. To satisfy the requirement of sight distance, a relation model was established for the attachment coefficient and the convex vertical curve radius. Using MATLAB simulation technique, the convex vertical curve radius at different attachment conditions was calculated accurately and a three-dimensional figure was drawn to describe the relation between the adhesive coefficient, the driving velocity and the radius of vertical curve. The correlation between the convex vertical curve radius and the adhesive coefficient was further analyzed and compared with National Technical Standards. The suggested radius of vertical curve was then put forward to provide a theoretical platform for the security design of the convex vertical curve.
基金supported in part by the National Key Basic Research Program of China(973 Program)(No.2015CB251002)the Science and Technology Project Funds of the Grid State Corporation of China(No.SGSNK00KJJS1501564)+2 种基金National Natural Science Foundation of China(Nos.51221005,51577145)the Fundamental Research Funds for the Central Universities of Chinathe Program for New Century Excellent Talents in University,China
文摘In this paper, the dielectric properties of CO2, CO2/air, CO2/O2, CO2/N2, CO2/CF4, CO2/CH4, CO2/He, C02/H2, CO2/NH3 and CO2/CO were investigated based on the Boltzmann equation analysis, in which the reduced critical electric field strength （E/N）cr of the gases was derived from the calculated electron energy distribution function （EEDF） by solv- ing the Boltzmann transport equation. In this work, it should be noted that the fundamental data were carefully selected by the published experimental results and calculations to ensure the validity of the calculation. The results indicate that if He, H2, N2 and CH4, in which there axe high ionization coefficients or a lack of attachment reactions, are added into CO2, the dielectric properties will decrease. On the other hand, air, O2, NH3 and CFa （ranked in terms of （E/N）cr value in increasing order） have the potential to improve the dielectric property of CO2 at room temperature.
