考虑上部结构的桩筏基础非线性共同作用分析

当前虽然已有考虑桩筏非线性的设计,但仍无人在此基础上,考虑上部结构。因此考虑上部结构,进一步认识其与桩筏基础非线性共同作用机理,优化桩筏基础设计,具有重要的现实意义。本文以子结构法凝聚上部结构的荷载及刚度,以平面壳体单元模拟筏板,按有限层法模拟桩土之间的弹性相互作用,用广义剪切位移法模拟桩的非线性工作性状,建立了一种考虑上部结构共同作用的桩筏基础非线性分析方法,并编制了分析程序。通过实例分析,探讨了上部结构与桩筏基础非线性共同作用的机理,研究了合理布桩方式,探讨了以差异沉降为目标的优化设计的可能途径。     

The strength of weak proximity

This paper studies weak proximity drawings of graphs and demonstrates their advantages over strong proximity drawings in certain cases. Weak proximity drawings are straight line drawings such that if the proximity region of two points p and q representing vertices is devoid of other points representing vertices, then segment (p,q) is allowed, but not forced, to appear in the drawing. This differs from the usual, strong, notion of proximity drawing in which such segments must appear in the drawing.Most previously studied proximity regions are associated with a parameter β, 0β∞. For fixed β, weak β-drawability is at least as expressive as strong β-drawability, as a strong β-drawing is also a weak one. We give examples of graph families and β values where the two notions coincide, and a situation in which it is NP-hard to determine weak β-drawability. On the other hand, we give situations where weak proximity significantly increases the expressive power of β-drawability: we show that every graph has, for all sufficiently small β, a weak β-proximity drawing that is computable in linear time, and we show that every tree has, for every β less than 2, a weak β-drawing that is computable in linear time.     

电动汽车制动能量回收最大化影响因素分析

对再生制动的原理和能量流动进行了分析,并讲述了制动功率、再生制动功率、制动能量回收效率等之间的关系和计算方法.从分析中得出电机、蓄电池、液压制动系统是影响制动能量回收的主要因素,并重点分析了制动管路布置型式对制动能量回收的影响.针对典型的理想制动工况,计算出前轴电驱动汽车在制动能量回收方面的潜力和制动能量回收效率,但结果并不理想.通过对比发现,双轴电驱动汽车无论是在制动能量回收潜力还是在制动能量回收效率以及制动效能方面都有能力达到最优.     

一种减少金属层数的芯片物理设计方法

数字后端物理版图设计是整个芯片设计的关键一步,而减少设计时所用的金属层数是IC行业中缩减芯片成本的一个重要措施。本文以SMIC0.18μm工艺下一款SmartCard芯片的实际设计方案为例,首先分析了金属层数与成本的关系,之后分析其可行性,并提出了具体的布局布线方案,最终以成功的流片结果论证了该减少金属层数设计方案的可行性。     

有机化学实验线上课程之扬长避短教学设计与实践篇

It has been two months since a boom of online education triggered by the epidemic in China. At present, we are keeping focus on how to optimize our online class. In the case of chemistry laboratory courses, there's not much that can be done to experimental operations through online teaching. While for the traditional teaching procedure, there is still room for improvement in terms of integrating research to teaching, interactivity, etc. This paper will present some design strategies for improving teaching the organic chemistry laboratory online. To be specific, it describes how teaching materials like the lesson plan and virtual lab were coordinated into the online teaching. And we will also discuss the holistic approach to a better outcome for students' active learning and integration research into teaching by redesigning multiple phases, such as the pre-laboratory preparation, live online class, experimental operations.     

城市公共交通线网优化的图论模型与算法

用图论方法,以城市客流OD分布为基本依据,给出了城市公共交通线网优化的圈论模型,并对Kuhn－Munkres算法作了一些改进,使之适应双向约束条件,并提高了运算速度;文中还给出了改进算法正确性的数学证明．本模型可用于大、中城市公共交通线网的优化     

风冷式发动机离心式冷却风扇的优化试验技术

介绍了为风泠发动机离心式冷却风扇优化实验研究工作面研制的万能试验风扇,试验叶片、叶片角度测量仪、风筒装置及其试验方法,以及获得的优化风扇在柴油机上的应用情况.     

车身焊装生产线机器人布局设计

通过分析机器人与夹具、修模器、换枪架和围栏的相对距离,以及机器人底座的高度研究机器人布局设计,并从目前的仿真项目中总结出机器人仿真项目中如何获得一个好的布局,有效地解决焊接过程中出现的干涉多、余量少等问题,同时还能够优化机器人的运动轨迹,减少工作的节拍。     

牙轮钻头主要结构参数的优化设计

根据牙轮钻头与岩石相互作用机理,引出了平面模型和空间模型的概念。平面模型反映牙齿在井底的刮切面积,空间模型反映了牙齿破碎岩石的体积。基于这两种模型分别建立了优化目标函数,并采用多目标优化方法对两种型号钻头(XHP2b和XHP3s)的主要结构参数进行了优化计算,结果表明对XHP2b钻头的优化效果比较显著。通过用优化后的结构参数重新设计制造出的钻头的现场应用情况很好,机械钻速提高10%-20%左右。     

从煤炭资源压覆议焦作市城建发展方向

焦作市是一座以煤炭为基础发展起来的矿业城市,已探明的煤炭资源主要分布在太行山山前受深大断裂控制的三角形地带内。老的城区已位于煤田分布区内,新的城建发展布局向南向东扩展,恰巧与煤田等展布方向一致,这种城建布局发展方向的不合理性,又将压覆大量的煤炭资源。面对新型,高效、环保的煤炭液化,煤炭地下气化等技术日臻成熟,焦作市等城建发展布局理应调整方向,向西南方向发展,为子孙后代预留下矿业经济可持续发展的空间。