高速磁浮车辆引起地面振动的数值分析

为预测高速磁浮列车引起的地面振动响应及其衰减规律,建立了高速磁浮车桥相互作用模型和磁浮线路桩基基础有限元模型,将磁浮车桥系统动力学仿真获得的车辆动态荷载输入基础有限元模型,计算了高速磁浮车辆引起的地面振动响应.计算结果表明:磁浮车辆引起地面振动响应的衰减规律与轮轨交通车辆的衰减规律基本一致,但在距离线路中心25 m左右没有反弹区;行车速度对磁浮线路地面振动的影响较大,当时速由125 km/h提高到430 km/h时,相同观察点处地面振动级增大约10 dB.     

协同办公系统的需求分析与实施

随着以计算机技术、通讯技术为代表的信息技术的发展,办公自动化在日常的管理、经营活动中发挥着越来越重要的作用.人们都要求办公自动化系统能适应不断变化的办公需求,既能提供公文处理等偏向个体的自动化办公功能,还要满足人们之间信息交换与共享的需求.本文结合学院的实际情况,探讨了协同办公自动化系统要如何实现,才能较大程度地满足用户不断增长和变化需要的问题.     

客流高峰期铁路客运组织策略探讨

客流高峰期需要对铁路运输能力进行重新分配、调整和加强.通过分析、总结高峰期客流的构成成分以及特性,比较客流高峰期与日常旅客运输组织的差异,从合理组织开行临时旅客列车、加强旅客售票组织,以及加强车站内部组织管理三方面来探讨客流高峰期旅客运输组织问题,为如何快速、有效地满足高峰期客流的出行需求、减轻高峰期铁路运输压力提供参考.     

Induction of animal model of Graves' disease in BALB/c mice

Objective To construct an animal model of Graves' disease (GD) by immunizing BALB/c mice with hM12 cells co-expressing major histocompatibility complex (MHC) class Ⅱ molecules and human thyrotropin receptor (TSHR) molecules. Methods BALB/c mice in experimental group (H-2d) were immunized with hM12 cells Intraper-itoncally every 2 weeks for six times, while mice in control group were immunized with M12 cells. Five weeks later, the thyroids were histologically examined, and serum samples were tested for thyroid-stimulating antibodies (TSAb) and thyroid hormone levels. Results One BALB/c mouse in experimental group developed Graves'-like disease. Total T4 and T3 levels in this mouse were above the upper limit of normal, TSAb activity was displayed in its serum. The thyroid histologically showed the features of thyroid hyperactivity including thyrocyte hypercellularity and colloid absorption.None of control mice developed Graves'-like disease. Conclusion An animal model with some characteristics of human Graves' disease was successfully induced and the model will facilitate studies aimed directly at understanding the patho-genesis of autoimmunity in Graves' disease.     

Effects of PYY on the interdigestive migrating myoelectric complex in the small intestine in vivo and the neural and endocrinal mechanisms of the effects

Objective To investigate the effects of peptide YY (PYY) on the interdigestive migrating myoelectrlc complex (MMC) in the small intestine in vivo and explore the neural and endecrinal mechanisms of the effects. Methods Spragne-Dawley rats were supplied with a venous catheter and bipolar electrodes in the duodenum and jejunum for electromyography of stomach and small intestine in wake state. PYY, phentolamine, nitro-L-arginine (L-NNA, the inhibitor of nitric oxide synthase) and atropine were served with PYY respectively. The plasma motilin levels before and after the infusion of PYY were observed. Results At all the three recording points, PYY lengthened the drde length of MMC [from (591.90±128.98)s to (999.25±216.59)s, P<0. 01] and lowered the frequency of phase Ⅲ [from (39.28±8.40) min-1 to (22.08±3.13) min-1 , P<0.01], amplitude of phase Ⅲ [from (0. 320±0.060)mV to (0. 179±0.030)mV, P<0.01], and the portion of phase Ⅲ over the whole circle length [from (28. 61 ± 5.84)% to (15.43 ±5.16)% , P<0.01]. Phentolumine had no influence on the role of PYY. Administered L-NNA combined with PYY, the percentage of phase Ⅲ increased [(42. 09±8.67)%] compared with that of control(P<0.01) and compared with that of PYY administered alone (P<0. 01) too. Atropine combined with PYY showed stronger depressing effects on MMC. No significant difference was found between the plasma motilin levels before and after the infusion of PYY. Conclusion PYY my inhibit the interdigestive intestine motility through the none-adrenergic none-choUnergic tract, while the m-receptor tract and circulating motilin are probably not involved In the depressing effect.     

基于改进局域波法的柴油机振动信号分析

提出了一种基于奇异值分解降噪的柴油机振动信号局域波分解方法,首先对原始振动信号进行相空间重构和奇异值分解,然后根据分解的奇异值降噪,接着利用经验模式分解法提取降噪后振动信号的基本模式分量,最后作出时频曲线和边界谱曲线。对滤波前和滤波后的柴油机振动信号进行了局域波分析,分析结果表明,奇异值分解能够有效地提高信噪比,突出原始振动信号的特征,使得降噪后的振动信号分解出的基本模式分量和时频曲线以及边界谱曲线具有更明确的物理意义,有利于对柴油机进行精确诊断。     

基于标准的车辆焊接结构抗疲劳设计与焊接工艺一体化设计

建立了一个车辆焊接结构抗疲劳设计及焊接工艺一体化的数据库系统,解决了抗疲劳设计与焊接工艺设计之间的信息孤岛问题,并嵌套了基于标准的焊接接头疲劳寿命计算模块．其中,对评估焊接接头疲劳寿命的国外标准（BS7608、IIW）进行了归纳,以便于用户使用,并与焊接工艺标准（DIN6700）进行了有机整合,实现了设计与工艺的一体化．此外,还嵌套了戚墅堰机车车辆工艺研究所多年累积的焊接工艺研究成果,使系统基础数据更加厚实与可靠．系统操作界面友好,有很好的实用价值．     

高速铁路对既有铁路枢纽的影响分析

高速铁路是世界铁路建设发展的方向.纵观我国<中长期铁路网规划>中"四纵四横"铁路的快速通道,高速铁路起讫点和经由点都位于既有大城市的铁路枢纽.因此,从枢纽车站、线路、疏解设备以及城市经济、空间格局、公共交通系统发展等角度出发,有关高速铁路引入对既有铁路枢纽及枢纽城市的影响的系统分析,可为交通运输发展总体规划及城市交通规划提供参考.     

基于旅客列车开行及停站方案的客流分配

客流分配是评价旅客列车开行方案的一个重要方面。通过分析旅客对列车选择行为的影响因素,旅客根据自己的意愿选择出行方案,考虑旅客乘坐列车的消费水平及拥挤费用,消费层次较高的旅客选择费用较高、旅行时间较短的乘车方案,消费层级较低的旅客选择费用较小的乘车方案,最终每个路段上的客流达到一个平衡状态。通过构造基于开行方案及停站方案的换乘网络,根据路段路径阻抗,利用梯度映射法进行求解该网络的客流分配模型,最终获得各OD对之间的多条出行路径方案。     

导管架海洋平台可靠性指标模糊优化分配方法

提出了近海导管架平台结构可靠性指标分配的模糊优化方法.该方法使导管架海洋平台在尺寸、重量、造价等约束条件下,体系达到模糊最优可靠性.文章从寻找结构主要失效模式、结构整体可靠度指标求解、结构子系统可靠度指标分配三个环节进行研究,得到了较为满意的结果.