2014年高考“平面向量”专题分析

对2014年全国高考文、理科数学试卷在平面向量专题的考查内容、方式和重点等进行整体评析;剖析了试题的创新特点;对2015年平面向量专题的备考提出了复习建议．     

Effects of roller burnishing process parameters on surface roughness of A356/5%SIC composite using response surface methodology

In this study, a simple roller burnishing tool was made to operate burnishing processes on A356/5%SIC metal matrix composite fabricated by electromagnetic stir casting under different parameters. The effects of burnishing speed, burnishing force and number of burnishing passes on the surface roughness and tribological properties were measured. Scanning electron microscopy （SEM） graphs of the machined surface with PCD （insert-10） tool and roller burnished surface with tungsten carbide （WC） roller were taken into consider- ation to observe the surface finish of metal matrix composites. The mechanical properties （tensile strength, hardness, duc- tility） of A356/5%SIC metal matrix composites were studied for both unburnished samples and burnished samples. The results revealed that the roller burnished samples of A356/ 5%SIC led to the improvement in tensile strength, hardness and ductility. In order to find out the effects of roller bur- nishing process parameters on the surface roughness of A356/ 5%SIC metal matrix composite, response surface methodol- ogy （RSM） （Box-Behnken design） was used and a prediction model was developed relevant to average surface roughness using experimental data. In the range of process parameters, the result shows that roller burnishing speed increases, and surface roughness decreases, but on the other hand roller burnishing force and number of passes increase, and surface roughness increases. Optimum values of burnishing speed （1.5 m/s）, burnishing force （50 N） and number of passes （2） during roller burnishing of A356/5%SIC metal matrix com- posite to minimize the surface roughness （predicted 1.232 μm） have been found out. There was only 5.03% error in the experimental and modeled results of surface roughness.     

俯身为桥 精神如虹-一组来自身边的教书育人楷模群像扫描

“知识不存在的地方,愚昧就自命为科学;教师不存在地方,无知就变成了聪慧.”35年,硕忍巴巴只做了一件事,一件对他来说极普通且平凡的事-与他的彝族学生为伴,带领他们看到更广阔的世界.硕忍巴巴：坚守彝乡村小35载硕忍巴巴,如果你不认识他,来到马边高卓营小学西泥沟村小,你一定能很快地从学生堆里把他找出来一头上戴着一顶黑色或浅黄的毡帽,身上穿着黑底白纹的盘扣马褂,总是这样一身极具彝族风格的“标配”着装,永远是一副精神抖擞的面貌.酷似“西部牛仔”的装扮下,深藏着几分侠客的坚毅与执着.     

一帆高挂 十年蝶变——临汾三中科学管理扫描

60年前的1954年,在汾河之畔的古老平阳大地上,临汾三中诞生了。60年来,临汾三中栉风沐雨,经过数代人的不懈努力,从小到大、由弱变强,成为享誉三晋的一所名校,为国家培养了成千上万名优秀人才,为临汾的经济社会发展和繁荣做出了巨大贡献。2014年,恰逢临汾三中建校60周年。回顾该校60年的发展历程,写满创业的艰辛,也写满了奋斗的辉煌。本期撷取临汾三中教育教学实践中的几个亮点,供大家借鉴分享。     

DIS实验系统在示波器教学中的应用

正一、示波器教学中的问题示波器是一种常用的电子仪器,内部核心部件是示波管,由电子枪、聚焦系统、偏转电极和荧光屏组成,管内抽成真空。如果在水平偏转电极XX'和竖直偏转电极YY'上都没有加电压,电子束从电予枪前聚焦系统射出后将汇聚在荧光屏上一点,形成一个亮斑。如果在偏转电极YY'上加正弦规律变化的电压,在偏转电极XX'上加扫描电压,荧光屏上就显示正弦曲线。在实验中通过调节扫描微调旋     

全球大数据扫描

今天,对信息资源的开发利用能力已经成为国际竞争以及国家整体实力的重要方面,当全球范围内数据成为国家资产、创新前沿,要成为“数据时代先驱者”时,我们需要学习、借鉴、消化和创新。例如美国、欧洲数据开放战略,韩国、新加坡的基础设施建设,日本智慧城市、医疗和农业等方面的创新等。     

浅谈如何进行高中数学探究式教学

<正>随着新课改在全国的普及,教学模式和教学方法的改变也随之而来,这对于全国的教师来说是一次巨大的挑战,尤其是数学教师.《普通高中数学课程标准(实验)》强调:高中课程应力求通过各种不同形式的自主学习、探究活动,让学生体验数学发现和创造的历程,发展他们的创新意识.已有的教学方式让学生感受到的只是数学的枯燥无味,因此,高中数学教师应设计能够充分     

民国大学讲义出版生态扫描

民国时期是我国现代大学教育从初创逐渐走向成熟的阶段,初期缺乏成熟的教学用书是困扰大学教员的一大难题。彼时一般通过两种方式解决,一是直接使用外国教材或其中文译本,二是根据课程情况由授课教员自编讲义,而后者在文科占了多数。因此,印发和使用授课讲义在民国大学校园非常普遍,中文、历史、哲学等学科教育中尤为常见。     

基于垂直扫描显微干涉技术的高精度轮廓仪

A profilometer used for 3 dimension measurement of micro-surface topography is presented. The instrument is based on the vertical scanning microscopic interferometry （VSMI）. A Linnik type interference microscope is used and the interferograms which present changes of surface profile are recorded with a CCD camera. A developed nano-positioning work stage with an integrated optical grating displacement measuring system realizes the precise vertical scanning motion during profile measurement. By a white-light phase shifting algorithm of arbitrary step, frames of interferograms are processed by a computer to rebuild and evaluate the measured profile. Because of the specialty of VSMI, the profilometer is suitable for both smooth and rough surface measurement. It can also be used to measure curved surfaces, dimension of micro electro mechanical systems （MEMS）, etc. The vertical resolution of the profilometer is 0.5 nm, and lateral resolution 0.5 μm.