发动机主动悬置3种控制方法的比较

应用LMS自适应前馈控制、LQR控制和模糊PID控制3种方法对发动机电磁式主动悬置进行研究.在MATLAB/Simulink环境下建立了主动悬置控制系统模型,并以车身垂向加速度为性能指标进行了仿真分析,对比了采用上述3种控制方法时主动悬置的隔振能力、鲁棒性和稳定性.仿真结果表明,在主动悬置的控制上模糊PID控制方法优于其他两种控制方法.     

Identification and culture of neural stem cells isolated from adult rat subventricular zone following fluid percussion brain injury

Objective To analyze proliferation and differentiation of glial fibrillary acid protein (GFAP)- and nestin-positive (GFAP+/nestin+) cells isolated from the subventricular zone following fluid percussion brain injury to determine whether GFAP+/nestin+ cells exhibit characteristics of neural stem cells. Methods Male Sprague-Dawley rats, aged 12 weeks and weighing 200-250 g, were randomly and evenly assigned to normal control group and model group. In the model group, a rat model of fluid percussion brain injury was established. Five days later, subventricular zone tissue was resected from each group and made into single cell suspension. After serum-free neural stem cell medium culture and subsequent serum-induced differentiation, cell type, proliferation and differentiation capacities were determined by immunofluorescence staining and flow cytometry. Results At 3-7 days after fluid percussion brain injury, nestin+/GFAP+ cells in the single cell suspension from the model group significantly outnumbered those from the normal control group (P<0.01). In the model group, an increased number of small neurospheres with smooth cell edge and bulged center formed after primary culture, and were clearly visible with the increase of culture time and medium replacement. After several passages, many clonal spheres were obtained, suggesting strong self-proliferatiing capacity. Neurospheres from the model group differentiated into astrocytes, neurons and oligodendrocytes. Conclusion GFAP+/nestin+ cells isolated from the adult rat subventricular zone after fluid percussion brain injury are thought to be neural stem cells because of their self-renewal and multi-differentiation capacities.     

跨京山铁路钢—混凝土组合箱梁体外预应力施工技术

北京市五环路京山铁路立交桥采用了钢-混凝土连续梁桥体外预应力技术,该桥在设计施工中存在很多难点问题。详细介绍了工程施工采用的转向器的安装、体外索套管的安装、钢绞线下料与穿束、体外预应力索的张拉、防松装置和减振器的安装技术,对今后的类似工程有借鉴参考意义。     

"自强"号油气处理平台电气设计概述

本文简要介绍了“自强”号油气处理平台的电源、主控制系统和探火系统。     

我国渔船的发展与展望

２０世纪９０年代,在近海资源衰退和亚洲金融危机不利条件下,我国海洋捕捞量仍呈增长势头。海洋机动渔船总量也基本上保持增长,并出现了船型多样化、节能化,出口批量增大等发展趋势。２１世纪,制约我国渔船发展的因素仍然很多,我国应继续开拓国外渔船市场,成为渔船出口大国。建造技术含量高的远洋渔船。在控制国内渔船总量的同时,以技术创新推动小型玻璃钢渔船的产业化。渔船的发展应与水产品加工、资源保护和开发、增养殖、     

拱桥非线性稳定分析

综合考虑了几何非线性和材料非线性对混凝土拱桥的影响．应用ANSYS对一座主跨为178m的钢管混凝土拱桥的施工中最不利阶段以及成桥状态进行了稳定性分析，为此类桥梁的设计施工提供参考。     

浅谈原材料对二灰结石基层质量的影响

原材料的质量,配合比的控制,以及施工过程的控制等因素,是影响二灰结石基层,施工质量的主要因素。     

轿车车身结构的有限元分析与评价

本文简述了用有限元法对轿车身结构进行与评价，也适用于其它类型车身的结构分析。     

多年冻土区路基遮阳板应用技术研究

青藏高原低纬度高海拔地区,太阳辐射是土体升温的直接热源,而带有融化潜热的雨水垂直渗流有加速下部冻结层融化的趋势。基于对辐射、避雨、保证蒸发散热边界条件等方面考虑,提出了一种积极主动的保持冻土路基稳定的措施——遮阳板路基。文内对这种新措施的工作机理进行了分析,并总结了试验实体工程设计与施工中存在的一些问题。通过对试验路段和对比路段观测、调查分析认为,遮阳板路基护坡是一种可行的保持路基稳定的积极有效的新方法。     

ZF低地板客车驱动桥齿轮、轴承受力计算与MASTA软件校核对比分析

以德国ZF低地板客车驱动桥为例,对螺旋锥齿轮、轮边斜齿圆柱齿轮系及轴承受力进行了系统分析,并与MASTA软件建立的驱动桥模型计算结果进行了对比,从而总结出驱动桥齿轮及圆锥滚子轴承、圆柱止推轴承受力与校核的一整套计算方法.另外,指出了目前MASTA软件在螺旋齿轮校核中的不足.