仰韶文化半坡类型彩陶器的艺术特点

半坡型彩陶文化是仰韶文化中历史较早,特点突出,影响较大的一个类型。器形丰富,多见圆底或平底钵、平底盆、鼓腹罐、细颈瓶。彩陶器的装饰纹样采用散点式构图,＂鱼纹＂和＂人面鱼纹＂以及由鱼头、鱼身演化而来的几何纹是半坡类型中最具特色的彩陶纹样。半坡型彩陶器造型规正,纹饰简洁生动,富有浓郁的原始气息,是当时经济、社会生活的艺术记录;同时反映了原始先民质朴的审美意识。     

超几何分布的期望和方差的一种新求法

本文介绍如何运用概率母函数来求超几何分布的期望和方差     

Neck-controlled sensitivity study on nano-grain SnO_2 gas sensors

1. Introduction SnO2 is an n-type semiconductor with rutile crystal structure and with a wide band gap of about 3.6 eV. SnO2 has a wide range of applications as photo-detectors, heat mirrors, transparent electrodes for solar cells, conductive filler, thick resistors, catalysts and gas sensors. One of the most important applications of SnO2 lies in gas sensors [1]. SnO2 gas sensors have been attracting much attention [2-5] because of their many advantages over current technologies for detect…     

Stewart formula and some inequalities for a simplex

1 Stewart formula and inequalities for a simplex Given a triangle ABC, suppose that , ,a bw w and cw are respectively the lengths of the angle bisectors of ?ABC, a, b and c are the lengths of the sides of ?ABC. The well-known Stewart’s formula for a triangle is proved as follows 222222222,( ),( ).( )abca bcw bc b cab cw ac a cabcw ab a b? = ?? +??? = ?? +??? = ? +?? (1) Let 1 2 1n nA A A? += be an n-dimensional simplex in the n-dimensional Euclidean space nE , V be the volume of ;n? kF…     

复数法在平面几何中的应用

对于正多边形、圆、旋转变换、等腰直角三角形等有关平面几何问题,用复数法来求解或求证显得较为简捷方便。     

基于OpenGL的三维图形绘制和3D建模

介绍了利用OpenGL实现三维图形绘制的基本编程框架和方法,对OpenGL中光照、材质、投影等关键技术的应用方法进行了重点阐述。简要介绍了利用3D Studio Max构建复杂模型,以降低用OpenGL构造复杂模型难度、减少建模工作量的方法。     

第一、二人称指示语映射使用的交互主观性功能探析

第一人称"我"和第二人称"你"在使用过程中,常常出现错位和虚化现象,即映射现象,其背后有着深刻的交互主观性功能实质。虽然不同的映射使用显示的交互主观性意义有差别,但都显示的是将听话人纳入话语中心,视作交际主体的语用策略。     

Teachers’ Critical Evaluations of Dynamic Geometry Software Implementation in 1:1 Classrooms

Although the use of dynamic software in high school mathematics in the United States has emerged as a research topic, little research has been conducted on how teachers integrate new software in relation to at-home technology networks. Interviews with eight mathematics teachers from four North Carolina counties participating in 1:1 laptop initiatives are analyzed to trace similar decision-making themes, including Internet access, laptop availability, software use, and teacher training. This article outlines how current technologies in classrooms were critically examined by the teachers and how network connectivity impressions affected hardware and software use.     

计算螺旋锥齿轮近似齿廓方程等距变换法

以机械工程中的近似取代为基点,运用微分几何中的等距变换理论为工具,建立起以渐开线为齿廓曲线的螺旋锥齿轮近似齿廓方程。     

对初中几何教学的几点认识

在初中几何教学中 ,要注重数学思想和方法的引导 ,充分激励和发挥学生学习的积极性 ,加强图形教学 ,通过“一题多解、一题多变”帮助学生开拓思维、提高能力 .