京包线张家口至集宁扩能提速方案研究

根据京包铁路张家口—集宁段现有运输能力 ,分析研究本段扩能提速方案 ,提出张家口—集宁新建第二双线方案。该方案具有通道内客货运营长度短 ,缩短旅行时间及货物在途时间 ,降低运营成本等优点。     

改进空压机控制方式

济西上行驼峰空压机站内设4台FHOG-100W型单螺杆式空压机，负责对上行驼峰场100余台设备提供制动和转换所需的动力源。从实际运行情况看，空压机存在的问题是：启停控制不稳定，造成风压下限、空压机频繁启停等，无法满足驼峰场设备自动化控制的要求。仅2004年3～6月期间，风压下限和空压机频繁启停故障就发生15件，占总故障件数的75％，存在较大安全隐患。     

汽车化摩托车的开发与研究

汽车化摩托车在原车基础上经过重新造型、有限元计算，各项特征参数均能满足使用要求，可替代小型摩托车或作为家庭的第2、第3辆车，在未来城市交通中将扮演购物，上学、进行各种休闲活动；上下班交通工具；邮递快运、警察执行公务、救援服务等角色，具有较好的发展前景。     

转K2型侧架支撑座组焊质量控制的建议

针对目前转K2型侧架支撑座组焊过程中的质量问题,提出了控制措施。     

京津城际轨道交通桥梁工程设计

以京津城际轨道交通为工程背景,对该工程中的桥梁工程特点进行分析,介绍桥梁工程设计中解决的多项关键技术问题,如常规桥梁式样、孔径的选择,特殊桥梁设计,软弱地基条件下无碴轨道桥梁沉降控制,采用新震规桥梁抗震设计及大跨度桥梁地震作用分析,区域地面沉降对策研究,桥梁建筑景观设计等,以及大跨度预应力混凝土无碴轨道桥梁施工控制关键技术研究和软土地基桥涵基础试验研究等科研项目,对京津城际轨道交通桥梁工程设计进行总结。     

浅谈TDCS数据库系统的优化

分析现有TDCS数据库存在的缺陷,通过制定优化解决方案的目标和实施重点,有针对性的提出了TDCS数据库优化方案,并通过可行性分析,得到优化方案可行的结论。对TDCS数据库实施优化方案后,可以提高数据库的可靠性和安全性,为铁路运输提供更高效的服务。     

预应力混凝土连续箱梁桥腹板主拉应力的计算与分析

以湖北随岳中汉江特大桥南岸堤桥为工程背景.采用有限元软件对该桥控制截面施工阶段以及运营阶段的箱梁腹板进行主拉应力的计算和分析.结果表明,主拉应力值都在规范允许值之内,为该桥在施工及运营过程中腹板是否产生斜裂缝以及结构使用的安全可靠性提供了理论依据.     

火柴厂软木尘对小鼠遗传毒性的研究

采集了北京火柴厂木屑提取液分别对小鼠骨髓嗜多染红细胞微核率的影响及SOS显色试验的研究。结果表明,微核实验的高(1.08)、中(0.43)剂量组均与阴性对照组有统计学上的显著性差异(P<0.05),并有微核率随受试物剂量升高而升高的趋势;SOS显色试验中各试验组的结果均为可疑,原液中有一组还为阳性,故不能排除木尘浸出液可造成DNA损伤的可能。     

Particulate Matter and Particle-Bound PAHs Emissions from Gasoline Direct Injection (GDI) Engine with Methanol-Gasoline Blended Fuel During Start

The effects of coolant’s temperature on emissions of particulate matters (PM) and particle-bound polycyclic aromatic hydrocarbons (PAHs) from a gasoline direct injection (GDI) engine were studied during the start process using gasoline (M0) and gasoline mixed with methanol in 15 % volume (M15). The engine worked at a certain idle speed automatically under different coolant’s temperature conditions after successful start. The experimental data was recorded from 0 to 40 seconds during the start. Results indicated that, there are significant differences in PM and particle-bound PAHs emissions between cold and warm start conditions. Particulate size distribution was measured with the Engine Exhaust Particle Sizer (EEPS) 3090. Compared with M0 fuel, the PM emission of M15 fuel decreased significantly, especially nucleation-mode particulate emission. The mass emission of PM was measured using the Gravimetric method. A same variation trend in PM mass emissions can be inferred for both fuels, i.e. it decreases while the coolant’s temperature increases. Compared with M0 fuel, the PM mass with M15 fuel reduces by 80 % at 20 oC coolant’s temperature. Agilent 7000B GC-QQQ was used to provide both qualitative and quantitative analysis on PAHs. The application of M15 fuel reduces the concentrations of most PAH species compared with M0 fuel, except those with smaller aromatic rings. In addition, Benzo(a)pyrene equivalent toxicity (BEQ) is calculated to evaluate the toxicity of PAHs emissions. The toxicity decreases when the GDI engine starts with higher coolant’s temperature or with M15 fuel.     

Effect of Heavy-Duty Diesel Engine Operating Parameters on Particle Number and Size Distribution at Low Speed Condition

Experiments and simulations were used to investigate the effect of a range of engine operating parameters and fuel characteristics on the particle size and particle number (PN) concentration at low speed and idle speed condition. The occurrence, size, and concentration of particles were tested against a range of parameters including start of injection (SOI), common rail pressure, exhaust gas recirculation (EGR) ratio and load. The results showed that the homogeneity of the mixture had the greatest impact on particle size and number concentration. The performance of particle is different at different levels of load. The particle were of nucleation mode at idle condition, and the cold idle particles had a slightly larger diameter than those produced at hot idle. By using the diesel and under high load, at EGR ratios of less than 20 %, most particles were of nucleation mode. At EGR ratios exceeding 20 %, nucleation-mode particles were gradually replaced by accumulation-mode particles. At EGR ratios above 30 %, most particles were of the accumulation mode. Under the same load, gasoline compression ignition produced particles of smaller size and reduced particulate mass (PM). The use of gasoline extended ignition delay, as the high volatility and octane number of the fuel improved the homogeneity of the mixture. Finally, a linear relationship was found between PM and PN. The relative contribution of the different factors to the formation of nucleationor accumulation-mode particles was investigated.