大型油罐底部边缘板的设计与焊接施工

大型油罐底部边缘板所受应力很大,并且容易腐蚀,罐壁与罐底边缘板连接区域容易断裂,严重影响油罐的安全使用,在设计和焊接施工中必须予以重视。分析了大型油罐底部边缘板的强度条件,介绍了边缘板的厚度设计、宽度设计方法,以及大型油罐底部边缘板的焊接施工方法及防腐焊接处理方法。     

一种改进的十字交叉轨道扣件定位方法

针对传统的十字交叉定位法对轨道扣件区域定位不准确,对图像要求较高,需要特定角度的光照采集才能实现扣件定位,定位过程较慢等问题,提出一种改进的十字交叉定位法对其进行定位。通过对其图像中扣件的初步位置判断定位,然后用中值滤波的图像增强,Canny算子的边缘提取,灰度投影的判断来提高定位准确性,加快定位速率,通过实验表明,改进的定位方法能够很好解决光照采集角度、快速有效的定位和判断出扣件,实现对扣件区域的初定位。     

风电安装船起重机回转支承接触分析

回转支承是起重机中最关键的部件,其强度直接影响起重机的安全性、可靠性.在分析自升自航式风电安装船浮式起重机承载工况的基础上,针对回转支承的结构特点,建立了同时承受轴向力、径向力及倾覆力作用下的有限元分析模型,并进行接触分析.分析结果表明,该回转支承的应力主要发生在三排滚柱与滚道的接触处,最大应力发生在第一排滚柱上,并且三排滚柱上都发生了偏载效应及边 效应.     

高速公路红粘土路基填筑施工与改良方法研究

依据红粘土液限高,随含水量的增加压实强度显著降低的特性,在路基94区以下通过严格控制路基填筑土层厚度和最佳含水量及选择合理碾压机具,优化碾压遍数直接进行路基填筑,在96区通过对红粘土掺人合理级配的碎石进行改良,及对红粘土路基的包边处理控制水对路基的侵润,抑制红粘土路基遇水变形大、土体强度大幅降低等病害,能保证红粘土路基的填筑质量。     

Edge effect of busy high traffic roads on the nest site selection of birds inside the city area: Guild response

The rapid development of road infrastructure is inevitable with increasing world human population and rise in the number of vehicles on the roads is going to be an increasing threat to native habitat of many wildlife populations around the world. The present work examines the edge effect of high traffic roads on nest site selection of birds in Udaipur city, Rajasthan (India). A total of 112 nesting site of 14 bird species (among six guilds), was recorded during the study. All six guilds (i.e., carnivore, omnivore, granivore, nectivore, frugivore and insectivore) were sharing similar kind of habitat with fine scale differences (P < 0.0001). The PCA revealed that trees with suitable GBH, canopy and height were supporting birds’ nesting diversity, but the buildings were supporting the highest number of nesting. Different guilds showed different preference to different variables. Spatial heterogeneity, less predation, optimal feeding ground and higher number of advertising and display boards of shops at roadside buildings might be crucial factors for birds’ nesting in this highly disturbed area.     

Research on the thrust output of a long primary double-sided linear induction motorEI北大核心

Research purposes: Based on Maxwell equations and T-type equivalent circuit of linear induction motor, we analyze the electromagnetic thrust output of a double-sided linear induction motor in the case of edge effect, and use the finite element method and simulation to test the effectiveness of the theoretical calculation. We further derivate the mathematical expressions of a double-sided linear induction motor, build the simulation model by parameter design, and experimentally analyze the slip frequency control thrust output in conditions of different operating. Through analysis of the output characteristics of the electromagnetic force, optimal control of constant current slip frequency is achieved. Research conclusions: (1) We calculate various mechanical properties of a bilateral linear induction motor through its mathematical model and equivalent circuit, and derive the corrected coefficients of the horizontal and vertical edge effect. When the motor runs at a high speed, the edge effect has little influence on the output of the electromagnetic force. (2) We use the finite element computer software to establish the simulation model of a bilateral linear induction motor, and compare the theoretical calculation and simulation data: the simulation results are consistent with theoretical calculation, thus ensuring the validity of the mathematical model. (3) We simulate and analyze the influence of slip frequency, speed, suspension air gap, and length of the mover on electromagnetic force. At different speeds, properly adjusting the slip frequency can increase the output of electromagnetic force. For low speed, the optimal slip frequency is near 2 Hz; for high speed, the optimal slip frequency is between 4.0 Hz and 6.0 Hz. When satisfying the motor's rated condition, the optimal control of electromagnetic force is achieved. (4) The research result of double-sided linear induction motor can provide important implications for the electromagnetic launch system of an aircraft carrier.     

基于SolidEdge的管件焊接空间位置优化算法的实现

针对管件在焊接过程中定位不够精确且制造误差较大的问题,在分析管件特殊性的基础上,采用旋转法对管件焊接空间位置进行了优化.提出了利用顶点对象的实现方案,并基于Solid Edge平台,利用VB语言加以实现.通过初步验证表明,此方法有效可行.     

基于路面图像对称性的车道偏离识别方法研究

利用车道边缘信息定义了边缘分布函数EDF,通过分析车道线在道路图像中的方向变化来判断车辆是否偏离了车道中央。将车道偏离识别问题通过EDF函数本身重要形态特征对称轴转换成一个数学问题,减少了动态道路场景噪声的影响,无需在测量车道方向时考虑摄像机自身的参数,提高了适应随机和动态道路环境的能力,是一种可靠的车道偏离识别方法。     

基于《电动客车安全技术条件》的客车侧碰试验研究

为了分析《电动客车安全技术条件》中客车侧面碰撞乘员保护试验方法的可行性,文章依据标准进行了客车侧面碰撞试验。通过分析侧面碰撞假人损伤情况,得到该试验方法无法复现乘员损伤较严重的客车撞客车侧面碰撞工况。通过分析试验车辆加速度曲线得到加速度传感器布置点,为客车侧面碰撞中乘员保护试验方法研究打下了基础。     

一种车牌定位的新方法

研究了一种定位车牌区域的新方法,该方法首先对车牌图像进行边缘检测,然后进行骨骼化处理,最后通过线扫描定位车牌。实验证明使用该方法定位车牌的准确率达到了98.8%,平均耗时0.1s,同时对光线较昏暗、车牌较模糊的图像也能实现比较准确的定位。