深圳地铁一期工程广深铁路桩基托换施工监测方案与实践

深圳地铁工程下穿广深铁路高架桥,需将两桥墩的桩基托换。文章介绍桩基托换施工中的监测技术,包括监测内容、系统组成、监测频率及托换桩施工、托换梁预应力施加、主动托换等的监测实施方法,保证了桩基托换的信息化施工。     

船企如何安全渡过动荡期——中国船舶工业行业协会会长张广钦谈应对金融海啸

在金融海啸的席卷下，2008年11-月5日，波罗的海航运指数（BDI）跌到了826点，半年时间跌去了93％，其下滑速度令人震惊。航运市场的冬天已经来临。受其影响，造船业也承受着巨大压力。在目前情况下，造船业的未来发展如何，怎样应对化解金融海啸带来的冲击与影响？就此，记者采访了中国船舶工业行业挤会会长张广钦。     

基于混合变量空间的轨道交通动态系统安全分析

在分析轨道交通动态系统安全相关要素的基础上,提出轨道交通动态系统是一类受时间、空间和事件多重驱动的混杂系统.在包含连续变量和离散变量的多维混合空间内,将轨道交通动态系统安全问题划分为多个动态子区间,进而实现对每一个动态子区间分别进行建模,然后依据各动态子区间的相互关联关系,聚合而得到系统整体模型的方法.分析了动态子区间的区间重叠外部特性和区间漂移内部特性.     

管理专业实践教学体系重构的思考

实践教学是培养学生研究能力、实践能力和创新能力的有效教学方式。本文通过论述目前管理类专业实践教学的现状,提出弊端,并就如何通过有效构建实践教学体系、提高实践教学质量、培养学生的创新能力提出自己的若干思考。     

利用停车技术缓解城市交通拥堵问题的研究

利用停车技术通过＂以静制动＂的方式来调控交通需求,减缓交通供需矛盾激化的速度。以缓解城市交通拥堵问题为主要目标,从城市停车问题出发,总结出4项停车技术,分别为区域不均衡停车供给技术、差别化停车收费技术、停车换乘技术和停车诱导技术,并对每项技术的基本思想、实施及其特点进行了分析,对缓解城市交通拥堵问题具有重要的参考价值。     

波浪作用下海床孔压滞后现象研究

利用室内实验模拟了波浪作用并对海床土中孔隙水压力的变化进行了监测,发现不同深度处的孔压存在的滞后性,研究了滞后性的具体表现形式。然后改变波浪的周期和土样的粒度级配进行对比试验,得到影响滞后性的诸因素:饱和度、波浪周期、波高、粒度级配、渗透性。     

Numerical study of the early injection parameters on wall wetting characteristics of an HCCI diesel engine using early injection strategy

Wall wetting in the early injection period has been proved to be unavoidable in the HCCI (Homogeneous charge compression ignition) diesel engine using early injection strategy, which directly affects in-cylinder fuel-air mixture formation. In this study, the effects of the early injection parameters (injection timing, injection angle and injection pressure) on wall wetting characteristics of an HCCI diesel engine using early injection strategy have been numerically investigated. The variations of maximum wall film mass, evaporated wall film mass and residual wall film mass have been summarized. The concept of MHI (Mixture Homogenous Index) is introduced to evaluate the homogeneity of fuel-air mixture in the wall wetting region. In additions, the effects of the early injection parameters on the HC (Hydrocarbon Compounds) and CO (Carbon Monoxide) emissions have also been discussed. Results showed that in order to decrease the HC and CO emission caused by wall wetting as low as possible, it was better to increase the injection pressure and to advance the injection timing. The most effective method was to narrow the injection angle, In addition, the impingement target should be considered for choosing the injection timing and injection angle, and the impingement target of the piston bowl lip was recommended due to the enhancement of the atomization and the higher surface temperature.     

Risk management modeling and its application in maritime safety

Quantified risk assessment （QRA） needs mathematicization of risk theory. However, attention has been paid almost exclusively to applications of assessment methods, which has led to neglect of research into fundamental theories, such as the relationships among risk, safety, danger, and so on. In order to solve this problem, as a first step, fundamental theoretical relationships about risk and risk management were analyzed for this paper in the light of mathematics, and then illustrated with some charts. Second, man-machine-environment-management （MMEM） theory was introduced into risk theory to analyze some properties of risk. On the basis of this, a three-dimensional model of risk management was established that includes： a goal dimension; a management dimension; an operation dimension. This goal management operation （GMO） model was explained and then emphasis was laid on the discussion of the risk flowchart （operation dimension）, which lays the groundwork for further study of risk management and qualitative and quantitative assessment. Next, the relationship between Formal Safety Assessment （FSA） and Risk Management was researched. This revealed that the FSA method, which the international maritime organization （IMO） is actively spreading, comes from Risk Management theory. Finally, conclusion were made about how to apply this risk management method to concrete fields efficiently and conveniently, as well as areas where further research is required.     

基于耐撞性的车身焊点动态失效研究及应用

基于车身耐撞性,对车身焊点热影响区的受力状态进行了分析,得到了基于许用剪应力和拉应力的焊点失效准则;基于失效准则对焊点进行了剪切及拉伸动静态试验,拟合得到了焊点的动态失效模型;将焊点动态失效模型带入子系统模型进行参数对标,将对标数据代入整车碰撞模型中,和试验相比得到了更加相似的焊点失效模式,提高了碰撞仿真的精准度。     

城市轨道交通中的屏蔽门系统

随着城市轨道交通日益快速的发展，各种新型技术得到了普遍的应用，站台屏蔽门系统是现代化城市轨道交通工程中的一种先进设施，是一项集机械、通讯信号、机电设备监控等专业为一体的城市轨道交通高新技术。它沿城市轨道站台边缘设置，将列车与站台候车区隔离。城市轨道交通安装屏蔽门系统，不仅可以防止乘客跌落或跳下轨道而发生危险，让乘客安全、舒适地乘坐地铁列车，