多段三次Bezier曲线插值几何模型的改进及实现

分析了一个多段三次Ｂｅｚｉｅｒ曲线插值几何模型，对其进行改进，简化了附加顶点的箕法，使插值曲线更为平滑。提供了一种绘制一阶连续光滑曲线的简便方法。     

新建客运专线无碴轨道几何尺寸验收标准的探讨

文章对国内外新建铁路无碴轨道几何尺寸静态和动态验收标准进行了比较和分析,对板式轨道和双块式轨道几何尺寸验收标准,提出了相应的建议值,同时,也对双块式无碴轨道几何尺寸的静态检测方法进行了详细的说明。     

滑动模板支架系统的设计与制作

介绍军山大桥引桥箱梁施工中针对工程具体情况所设计的滑动模板支架系统的基本结构，技术指标，参数以及安装，使用效率等。     

秦沈客运专线道岔综述

介绍了法国，德国和日本高速铁路道岔概况及我国秦沈客运专线18号，38号道岔的几何结构特征，现场铺设，动态测试等情况，并据此对上述2种道岔作了分析和评价，提出高速道岔尚需研究解决的问题。     

中心仿射超曲面的热方程

假设初始流形是仿射空间中的局部严格凸的紧致无边的光滑超曲面，坐标原点在曲面凹的一侧，位置矢量与曲面横截，利用欧氏支撑函数，得到中心仿射超曲面的热方程的解在任何有限时间区间内都存在，并又保局部严格凸性及位置矢量与解曲面的横截性，当时间趋于无穷大时，解曲面收缩于一点。     

一种新型滑动模板装置及施工方法研究

以桥梁高墩施工为背景,针对等截面高墩施工特点,对目前主要施工设备的不足进行改进,爬模系统、翻模系统施工工序复杂、工效低;滑模系统工效高,但是混凝土外观质量差不能满足规范要求。该文研发一种施工速度快、混凝土表面密实度好的复合滑动模板装置,总结了该装置及施工方法的结构优点和施工要点,可为同类施工提供借鉴。     

优化数模质量PDQ

<正>数字化模型对于汽车设计来说非常关键。作为整个开发周期中的重要因素,产品数模的几何质量直接影响到最终产品。对于汽车及零部件制造商来说,因质量问题而造成的各种浪费给企业增加的成本不菲。为了有效控制质量,除了加强制造工艺外,如何在设计源头提升产品质量显得尤为重要。数字化模型对于汽车设计来说非常关键。作为整个开发周期中的重要因素,产品数模的几何质量直接影响到最终产品。PDQ(产品数据质量)理念在     

Examining the effect of speed,roadside features,and roadway geometry on crash experience along a rural corridor

This paper presents a current investigation into crash experience along a 15.7-mile rural corridor in southwest Montana with the aim of better understanding crash causal factors along the corridor. The study utilized ten years of crash data, geometric data, and observed freeflow speed data along the corridor. A systematic approach was used where every tenth of a mile was described in term of the crash experience, speed, alignment, and roadside features. Using bivariate and multivariate statistical anal-yses, the study investigated the crash experience along the corridor as well as some of the underlying relationships which could explain some of the crash causal factors. Results show a strong association between crash rates and horizontal curvatures even for flat curves that can be negotiated at speeds above the posted speed limit, per the highway design equations. Higher crash rates were also found to be associated with the difference between the observed free-flow speeds and the speed dictated by the curve radius or sight distance as per the design equations. Further, results strongly support the safety benefits of guardrails as evidenced by the lower crash rates and severities. The presence of fixed objects and the steepness of side slopes were also found to have an effect on crash rates and severities.