汽车车窗的改良

随着现代汽车迅速发展,汽车的车窗越来越多样化与人性化,但仍存在一些不足之处.本文通过采用双层车窗以及可调风向多孔车窗的形式,对汽车的车窗进行了一些改良,使其在保证基本性能的同时,能满足乘客的更多需求.     

基于Trans Modeler的城市快速路交通设计方案的微观仿真评价

基于Trans Modeler仿真平台对北京市通惠河北路开前后两个方案进行了评价分析,详细阐述了Trans Modeler仿真平台下交通微观仿真的技术路线、方案设计以及OD反推技术的实现和输出指标的分析方法,对新开通的城市快速路的分担率进行了量化评估,并给出了评价结论。     

Determination of enantiomeric impurity of etomidate by high performance liquid chromatography

Objective To determine enantiomeric impurity of etomidate using high performance liquid chromatography. Methods (R)-etomidate and (S)-etomidate were isopropanol-n-hexane. The flow rate of the mobile phase was 0.5mL/min. The detected wavelength was 242nm. Results (R)-etomidate and (S)-etomidate could be separated completely under these conditions. The precision of (R)-etomidate was 1.57% (n=3). The limit of detection of (R)-etomidate was 4.25ng/mL. The average percentage content of (S)-etomidate was 0.09% in the samples. Conclusion The method was repeatable and sufficiently sensitive to determine the enantiomeric impurity of etomidate. It allows the quantitation of the impurities at the 0.085% (w/w) level relative to etomidate at a concentration of the test solution of 5mg/mL.     

六四梁、八三墩拼组的异形架桥机在32m单线箱梁架设中的应用

郑西客运专线张家湾3号桥分左中右3幅,在架设左右幅单线箱梁时,采用的施工方案为利用已经架通的主线梁,在主线梁上整孔现浇32m单线箱梁,然后利用六四梁和八三墩组装一台垂直桥向的的异形架桥机,将整孔梁架设到位。实践证明,六四梁和八三墩拼组的异形架桥机造价低、适用性强,有效缩短了工期,适用于大跨度、高难度、地形环境差等高危险性桥梁架设工程。     

Rapid analysis of components in Rhizoma Anemarrhenae by HPLC-DAD-MS and HPLC-DAD-TOFMS

A global quality control method based on high performance liquid chromatography (HPLC) coupled with diode array detection (DAD), single quadrupole mass spectrometry (MS) and time-of-flight mass spectrometry (TOFMS) was developed for simultaneous determination of seven major components (mangiferin, neomangiferin, timosaponin E1, timosaponin E, timosaponin BⅡ, timosaponin BⅢ, and timosaponin AⅢ) and identification of most components in extracts of Rhizoma Anemarrhenae (RA). HPLC analysis was performed on an Agilent SB-C18 column (4.6 mm×150 mm, 5 μm) by gradient elution using acetonitrile and water-acetic acid(100∶0.05, v/v) as the mobile phase. Seven major components in RA were successfully separated. This quantitative method was fully validated in respect of the following performance criteria: linearity, precision, repeatability, stability, accuracy, limits of detection (LOD) and quantification (LOQ). A formula database of known compounds in RA was established, against which, most of the reported components in this herbal extract were identified effectively based on the extract masses acquired by TOFMS. This qualitative and quantitative method was successfully used to analyze the components in 10 batches of RA samples collected from different regions in China. This global quality control method, which consisted of HPLC-DAD-MS assay of seven major components and unambiguous identification of nineteen components, is suitable for routine quantification and comprehensive quality control of RA.     

渗碳处理20CrMnTiH和20CrNiMoH*齿轮材料滑动摩擦学特性研究

采用环块运动方式对经渗碳处理的20CrNiMoH*,20CrMnTi齿轮材料在润滑条件下的滑动摩擦磨损性能和磨损机理进行了试验研究.试验结果表明,不同材料20CrMnTiH和20CrNiMoH*配副的摩擦因数最低为0.111,20CrNiMoH*同材料配副的摩擦因数为0.117,而20CrMnTiH同材料匹配的摩擦因数最高为0.120.不同材料匹配耐磨性能由高到低的顺序为:20CrNiMoH*与20CrNiMoH*>20CrNiMoH*与20CrMnTiH>20CrMnTiH与22CrMnTiH;润滑滑动摩擦条件下的渗碳齿轮材料滑动磨损机理主要为点蚀磨损和磨粒磨损.     

城市环岛广场人车矛盾问题分析

中国城市大多数都是在原有城镇的基础上发展起来的,尤其我国一些主要城市在20世纪初沿用了西方的城市规划思想,将放射状的城市道路系统应用在城市规划中,形成了带有环岛广场的放射状的城市道路系统。该文通过分析这些城市的环岛广场人车矛盾现象,归纳出环岛广场人车矛盾的三种类型,并总结出环岛广场人车矛盾的主要特征,最后提出了城市环岛广场规划建设的几点思路。     

Bus journey times in medium size urban areas

The predictive accuracy of the models based on the fundamental relation between journey time and passenger demand can be improved through data disaggregation or route segmentation. Primary reason for this is the improvement in the estimates of stopping delays and delays due to passenger boarding and/or alighting (dwell time). Both Poisson and Negative Binomial model estimates of stoppings for passenger boarding and alighting are shown to improve with disaggregation. These improvements, however, contribute little to the overall predictability of the fundamental models which are useful for gaining insight into the significance and variability of the stopping delays and dwell time, or testing sensitivity to changes in the long term. Site or route specific models of journey times which have better predictive capability exist, and may be used for short-run planning. However, the interchangeability and performance over time of the latter, have to be evaluated before making definitive conclusions.     

五轴转向重型汽车转向性能的研究

以多体系统动力学理论为基础,利用ADAMS建立了五轴转向重型汽车的整车虚拟样机模型,对该模型进行了仿真分析.由分析结果可知,转向轮转角越大,轮胎磨损越严重.为提高重型汽车的灵活性,延长轮胎的使用寿命,对该模型进行了优化.通过仿真分析可知,优化后的转向性能明显提高.同时分析比较了五轴转向重型汽车与前两轴转向重型汽车的转向性能,结果表明,五轴转向重型汽车转弯半径小,轮胎磨损小.     

客车安全锤的关键性能要求的试验研究

提出安全锤的关键性能要求及试验方法,并通过试验过程和结果分析其关键性能的控制参数.