Field investigation on effects of railway track geometric parameters on rail wear

INTRODUCTION Among the numerous components used in the railway industry for high axle load operations, wheels and rails comprise a major source of running expen- diture. The wheel/rail interaction is the main technical factor determining design procedures and mainte- nance and replacement schedules for both vehicle and track. The rail wear is one of the most important factors causing reduction of the railway track life cycle. The re-profiling and replacement of worn wheels and rails is re…     

Riemann and theoretical physics

Several mathematical disciplines such as differential geometry, topology and Riemann geometry on which Riemann left his mark have a major impact on physics today. This article describes some of these contributions of Riemann to physics.     

构造不同图形 培养发散思维

通过构造不同的图形去解一个几何概型问题，联想到发散思维能力的培养。     

图像边缘检测新技术及其应用

综述了目前具有代表性的四种边缘检测新技术,并且对这些边缘检测新技术的应用进行了总结,最后通过对比分析了各自的优缺点.     

解析几何的创立及其在近代科学认识上的作用

解析几何的创立开拓了一个数学发展的新领域,数学知识成为近代科学发展的基础,数学演绎法成为科学认识的重要方法。由于这一新的数学理论,使运动进入了数学,微积分和牛顿机械力学被发明。最终近代科学、近代哲学理性认识论得以形成。     

画法几何与现代工程图学教学改革

画法几何的创建具有投影作图理论教育和素质教育的双重意义.国内工科院校对其后一作用某种程度上存有偏见.新时期的画法几何教学应致力于锻炼学生的工程设计能力、立体思维能力以及创新能力,以此推动现代工程图学的课程设置、教材建设、教学手段改革及师资队伍建设,促进现代工程图学教学改革的发展.     

On the argument of simplicity in Elements and schoolbooks of Geometry

Simplicity arguments are to be found in most geometrical works, from those of Proclus in his Commentaries on the First Book of Euclid’s Elements, up to those of contemporary manuals. Our goal is to read these arguments in their historical contexts to analyze agreements, disagreements and the multiplicity of points of view. For a better apprehension and a better understanding of the different conceptions, we will focus on the notion of angles and their measurements. We will study the notion of ≪ simplicity ≫ in various Elements of Geometry, in particular those of Euclid, Peletier du Mans (1628), Arnauld (1667), Lacroix (1803) and Hoüel (1867). From there, we will examine French schoolbooks of geometry, beginning from the 1960s up to the 1990s, including those of the so-called period of ≪la réforme des mathématiques modernes≫ in France.     

空间解析几何中的三垂线定理

本文中利用空间坐标和空间向量把立体几何中的"三垂线定理"推广到空间解析几何中,并证明。     

平面点集的一个极值问题

设S是欧氏空间Rm中由有限个点A1,A2,…,An组成的集合.d（Ai,Aj）表示点Ai和Aj之间的距离.令σ（S）=1Σ1≤i≤j≤nd（Ai,Aj）,d（S）=1min 1≤i≠j≤n{d（Ai,Aj）},μ（m,n）=σ（S）/d（S）（S包含R^m,｜S｜=n）,infμ（m,n）=min{σ（S）/d（S）｜S包含R^m,｜ S｜=n}这里通过区域控制、求边界极值等分析方法证明：当平面五点为凸形顶点时必有μ（2,5）＞9＋2√3.此外还提出几个猜想.     

中学几何教学中数学思想方法的渗透与运用

简要介绍了中学数学思想方法,并通过实例讨论了如何在中学几何教学中体现数学思想方法