锚杆支护原理的另类解释

锚杆支护的一般作用原理是提高围岩各向力的平衡程度。锚杆支护在特殊条件下的作用原理是对围岩吊挂固定。对比使用锚杆前后围岩基本力学参数变化,可以看到锚杆调整围岩应力平衡的作用,远大于吊挂固定围岩的作用,围岩应力分布状况是锚杆设计安装的依据。     

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.     

既有铁路钢桁梁桥运营性能的检测与评价

阐述既有铁路桥梁评价的内容和标准,针对评价标准提出了相应的检测方法。在朔黄铁路64m栓焊下承式钢桁梁双线铁路桥的应用实践证明,该评价标准和检测方法对既有铁路钢桁梁桥运营性能的评价是合理的。     

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。     

大直径泥水盾构刀盘刀具应用技术

长大隧道地质情况变化较大,盾构施工中刀盘刀具面临较多问题,尤其刀盘的磨损及刀具损坏是施工中经常遇到的一大难题,加强刀盘刀具技术管理成为大直径复杂地层泥水盾构施工管理的重要环节。文章以广深港客运专线狮子洋隧道盾构施工为例,从影响刀盘磨损及刀具损坏的原因分析至对刀盘的技术管理进行了分析研究,总结出了大直径复杂地层泥水盾构施工刀盘应用技术,对类似项目的盾构施工具有一定的借鉴和参考价值。     

"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。