多层砖混结构的扩展基础与刚性基础的比较

随着住房制度改革政策的实施,各种经济适用房(刚性基础)的建设以其较经济的造价,发展较快;如能采用钢筋混凝土扩展基础,在结构构造和经济效益上有更大的优势.     

一类无穷维动力系统的分叉问题

本文用Ｌｉａｐｕｎｏｖ－Ｓｃｈｍｉｄｔ方法和Ｆｒｅｄｈｏｌｍ方法研究了一类自偏微分方程描述的无穷动力系统的分叉问题，证明了当雷诺数增至π＾２时，系统发生超临界的音叉分叉。用摄动法确定分叉解的稳定性。     

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.     

洋河大桥桥梁病害处理及加固设计

针对已有桥梁病害及桥梁使用工况改变进行有目的桥梁结构加固设计,有关加固措施及施工经验可为类似桥梁加固提供借鉴。     

高速道岔质量监督管理探讨

根据高速道岔监造管理办法,介绍道岔质量监督工作概况。在分析道岔各生产环节质量控制特点的基础上,提出关键环节的控制重点,并从技术标准、质量体系、管理办法、沟通机制、团队建设和政策支持等方面提出建议和办法,以进一步完善道岔质量监督工作,提升产品质量把控水平。     

案例教学法在计算机教学中的应用

案例教学法是一种以经典案例为中心开展教学活动的教学方法,能够更好的拓展学生的思路,使学生更迅速的掌握计算机知识点。因此在计算机专业课程中应用案例式教学法,不仅能改变打破陈旧单一的课堂教学方式,还能为学生增加丰富课外实践内容,在很大程度上促进学生主动学习的热情,对培养学生自主学习意识,丰富实践操作经验很有帮助。与传统教学模式相比,引入案例教学的课堂具有趣味性,案例分析能够串联计算机多种知识点,让学生同步掌握计算机基本操作技能、技巧,积累实践应用经验,实现“知识传授”向“能力培养”的教学目的,达到“通过树木见森林”的教学效果,还能使学生对于学习由“被动”转变为“主动”,学生主体性更强。     

我国客运专线GSM-R网络建设方案的建议

欧洲铁路联盟确定GSM-R为欧洲铁路无线通信的标准制式,该制式为列车控制系统提供了信息传输平台,使欧洲跨国列车可以畅通运行。我国铁路技术政策也规定GSM-R作为我国铁路综合数字移动通信系统,并在青藏线、大秦线和胶济线进行GSM-R典型工程试点,为我国铁路客运专线GSM-R网络建设积累经验。建议GSM-R核心网建设应采取总体规划、分步实施的原则,采用智能网解决GSM-R网络的互联互通,客运专线按照预留双网条件建设,初期按无线列车控制系统的覆盖要求建设单层网络,重点解决场强覆盖问题。     

驼峰可控顶自动调速系统控制技术研究与应用

根据可控减速顶的调速原理，介绍驼峰可控顶自动调速控制系统的控制技术。通过设计相关的软件和硬件，对溜放车组进行精细位置跟踪，实现变速控制。应用效果表明，此系统具有控制精确、可靠性和安全性高等特点，满足运输生产要求，适用于我国中小驼峰现代化改造。     

Small scale retentive structures and Dinophysis

Despite its rarity, Dinophysis acuminata is in terms of economic impact, the first toxic algal species along the coasts of Western Europe. It is observed at low levels (< 20 cell l^− 1) all the year round but toxic events occur mainly in late spring and summer. D. acuminata ecophysiology is largely unknown due to the inability to culture it. Therefore, standard biomass models based on inorganic nutrition are largely inadequate. Presently, any progress in describing the conditions of population growth of this species will be a step forward to prediction of harmful events at the coast. This species has been observed at increased, albeit low cell densities in retentive eddies located in pycnocline layers. A concentration build-up of one species results from the balance between growth and loss processes, one of the latter being dispersal. The scales of interest for a D. acuminata population are of the order of 10 nautical miles on the horizontal and duration of 10 days, for a reported achievable growth rate of 0.6 day^− 1. A three dimensional (3D) hydrodynamical model of the Bay of Biscay has been elaborated to reproduce hydrological structures over the last decade. We attempt here to relate the existence of retentive structures revealed from simulations under realistic forcing conditions and the toxic coastal events recorded in the 10-year time series of the French plankton monitoring network database. The eddies in the coastal area appear to be directly related with the Dinophysis coastal events and they may be a potential effective tool to predict those.     

可靠性理论在城市轨道交通供电系统中压环网分区设计中的应用

定性分析已难以满足城市轨道交通中压环网分区方案精细化设计要求,必须以定量分析作为评价或研究的基础。根据可靠性理论,采用马尔可夫状态空间法、最小路集法建立了城市轨道交通中压环网分区模型,结合具体工程对中压环网分区方案与车站变电所可靠性进行了定量分析。建议在前期设计时,应采用可靠性理论对年平均停运时间进行评估,以确定兼顾经济性和可靠性的中压环网分区方案。