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This paper proposes a new dynamic bus control strategy aimed at reducing the negative effects of time-headway variations on route performance, based on real-time bus tracking data at stops. In routes with high demand, any delay of a single vehicle ends up causing an unstable motion of buses and producing the bus bunching phenomena. This strategy controls the cruising speed of buses and considers the extension of the green phase of traffic lights at intersections, when a bus is significantly delayed. The performance of this strategy will be compared to the current static operation technique based on the provision of slack times at holding points. An operational model is presented in order to estimate the effects of each controlling strategy, taking into account the vehicle capacity constraint. Control strategies are assessed in terms of passenger total travel time, operating cost as well as on the coefficient of headway variation. The effects of controlling strategies are tested in an idealized bus route under different operational settings and in the bus route of highest demand in Barcelona by simulation. The results show that the proposed dynamic controlling strategy reduces total system cost (user and agency) by 15–40% as well as the coefficient of headway variation 53–78% regarding the uncontrolled case, providing a bus performance similar to the expected when time disturbance is not presented. 相似文献
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目的 通过变异链球菌黏结素蛋白和唾液蛋白的相互作用,筛选全唾液中变异链球菌黏结素蛋白的受体成分.方法 变异链球菌国际标准菌株经活化、液体培养,采用冷冻乙醇法提取在液体培养时细菌分泌至培养液中的黏结素,并对黏结素的成分进行电泳分析、含量测定和抗原性检测.选取15名高龋者和15名无龋者,分别于进食后2h采集其无刺激性全唾液,经冷冻干燥后制备电泳样品,采用SDS聚丙烯酰胺凝胶电泳(SDS-PAGE)将其分开,用变异链球菌黏结素蛋白和变异链球菌的抗体成分进行Western-blotting免疫印迹检测.结果 在细菌培养液中提取到了变异链球菌表面分泌的黏结素成分.免疫印迹检测结果显示,唾液中变异链球菌的受体成分至少有6种,不只局限于目前认识的富脯蛋白等3种.结论 变异链球菌表面黏结素可与全唾液中的多种蛋白结合,这有可能是变链菌黏附于牙齿表面的物质基础. 相似文献
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对于高频率公交线路服务,以减少在站乘客平均等待时间为目标,提出以车头时间距的一致性来分析和衡量线路级别的公交服务可靠性的方法。考虑乘客需求波动和线路运行时间随机性对公交服务可靠性的影响,以一条高频发车的固定公交线路为考察对象,利用随机模拟方法仿真公交服务过程,计算分析了不同乘客需求和运行时间波动情况下的车头时间距的变异特征和在站乘客平均等待时间。结果表明,线路运行时间波动越大,乘客到达越不均匀,车头时间距变异就越大,乘客平均等待时间也就越长;随着站序的增加,累计车头时间距变异趋向于增大,服务可靠性逐渐变差。 相似文献
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探讨急性缺血性脑血管病红细胞免疫粘附功能的变化。方法 测定急性期腔隙性脑梗塞 2 7例 ,动脉粥样硬化性血栓形成性脑梗塞 2 3例红细胞 C3 b受体花环率 ( RBC· C3 b RR) ,红细胞免疫复合物花环率 ( RBC·ICR) ,血清红细胞免疫粘附促进因子 ( RFER)及血清红细胞免疫粘附抑制因子 ( RFIR)。结果 急性缺血性脑血管病患者 RBC·C3 b RR及 RFER明显降低 ,而RBC· ICR明显增高 ( P <0 .0 0 1 ) ,急性期腔隙性脑梗塞与动脉粥样硬化性血栓形成性脑梗塞患者红细胞免疫粘附功能各项指标无明显差异 ( P >0 .0 5)。结论 红细胞免疫粘附功能与急性缺血性脑血管病关系密切 相似文献
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Salivarylipids,asasortoforganiccomponentsofsaliva ,playanimportantroleinoralphysiologyandpathology .Thepreviousstudiesaboutsalivarylipidsfocusedonitsorigin ,itsrelationshipwithcariesanditsrelationwithsalivary glycopro tein[1-3 ] .Buttherearefewstudiesonsaliv… 相似文献
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徐静 《西安交通大学学报(英文版)》1995,(1)
STUDYONTHEIMMUNEFUNCTIONOFERYTHROCYTEINPATIENTWITHNIDDMXuJing(徐静)(DepartmentofEndocrine,SecondAffiliatedHospital,Xi'anMedical... 相似文献
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介绍了制备高硬度耐腐蚀搪瓷层的方法和提高搪瓷层硬度与耐腐蚀性的措施,在对钢板进行脱碳和酸洗预处理的前提下,采用一次涂搪法制备搪瓷.用金相显微镜和扫描电子显微镜观察搪瓷层与基板结合界面处的显微形貌,用X-射线衍射仪(XRD)分析搪瓷层的相结构,用显微硬度仪测试晶化处理前后搪瓷层的硬度,考察晶化处理对搪瓷层硬度的影响.实验结果表明:随烧结温度的提高,搪瓷层与基板的结合性增强;瓷的最佳烧结工艺是在970℃烧结5min.根据XRD分析结果可知,搪瓷层通过在920℃保温14min的晶化处理后出现NaAlSiO4和NaAlSi2O6相.在970℃烧结5min的搪瓷具有优异的性能,其硬度为7.30GPa高于一般搪瓷的硬度;耐热温度为700℃是化工部规定的搪瓷耐热温度的2倍;同时其热震温度为500℃是搪瓷化工设备标准规定耐温急变温度的2倍;耐酸等级为A级,耐碱质量损耗为1.793mg/cm^2. 相似文献
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