钢的奥氏体晶粒度试验中影响晶粒大小因素的研究

本文综合了大量文献资料，就钢中酸溶铝含量、加热方式和奥氏体晶粒的显示方法对奥氏体晶粒大小、晶粒粗化温度的影响进行了较详细的分析研究。     

平滑Chahine迭代算法在光散射法粒度分布反演中的应用

光散射法粒度测试涉及到粒度反演技术.随着反演粒级数的增加,通常的粒度反演法将出现严重的振荡.文章将Chahine迭代算法与平滑滤波技术相结合解决了高反演粒级数下数值解的振荡,在不改变激光粒度仪的原有结构情况下,就可明显提高仪器的精度和分辨能力.     

Sample, Random and Variation: The Vocabulary of Statistical Literacy

This paper considers the development of school students’ ability to define three terms that are fundamental to statistical literacy: sample, random, and variation. A total of 738 students in grades 3, 5, 7, and 9 were asked in a survey to define and give an example for the word “sample.” Of these, 379 students in grades 7 and 9 were also asked about the words “random” and “variation.” Responses were used to describe developmental levels overall and to document differences across grades on the understanding of these terms. Changes in performance were also monitored after lessons on chance and data, emphasizing variation for 335 students. After 2 years, 132 of these students and a further 209 students who were surveyed originally but did not take part in specialized lessons, were surveyed again. The difference after 2 years between the performance of students who experienced the specialized lessons and those who did not was considered, revealing no differences in performance longitudinally. For students in grades 7 and 9, the association of performance on the three terms was explored. Implications for mathematics and literacy educators are discussed.     

Teaching NHCE with Cross-Cultural Simulations

Cross-cultural communication competence is very important for the students who study English as a second language. In order to teach effectively.the teachers may try to teach with cross-cultural simulations.The au- thor Of the article uses 5 simulations in the course of New Horizon College English.Although the sample size in this research is small,the author shows the ideas that cross-cultural awareness is related to communication competence and teaching with cross-cultural simulations helps understanding.     

中原城市群的城市规模结构分析

本文选用城市的首位度,城市金字塔,以及位序-规模法则对中原城市群九个城市的规模结构以及未来趋势进行分析,得出中原城市群发展中存在的问题,以及解决这些问题的相关对策。     

从信贷供求角度谈我国中小企业融资问题

目前我国直接融资市场并不发达,中小企业外源性融资主要是银行信贷融资。然而,信贷融资供求双方的种种原因使得这种融资渠道不畅,严重影响了我国中小企业以至整个经济的发展。因此,文章分析其成因并提出了相应的对策。     

中国非英语专业研究生词汇量不同词频等级分布状况研究

本文探讨了中国非英语专业研究生的接受性和产出性词汇量在高频、中频、低频以及学术类词汇四个词频等级的分布情况。上海市两所重点高校的360名研究生参加了两种分别测量学习者接受性和产出性词汇的词汇测试。研究结果表明,我国非英语专业研究生能够掌握大多数高频词和学术类词汇的基本含义,但由于他们对中低频词,尤其是低频词的认知率较低,在今后的学习中仍有可能面临词汇上的困难;研究生的产出性词汇量要远低于其接受性词汇量,且大部分产出性词汇仍属于高频词;尽管学生对学术类词汇的认知率较高,但他们在该词频上的产出性词汇量仍有待进一步提高。针对上述结果,研究建议在研究生英语教学过程中教师应注意对学生词汇学习策略的培养,并通过数据驱动学习、转变写作任务模式等途径扩大学生的产出性词汇量。     

类规模对面向对象度量与易维护性关联关系潜在混和效果元分析

用在设计阶段可以收集到的3个规模度量分析类规模对面向对象度量与易维护性之间关联关系的混和效果.为得到尽可能通用的结论,在127个C＋＋系统和113个Java系统上分析类规模的混和效果.首先,对每个面向对象度量,在单个系统上计算代表由类规模造成的关联扭曲的间接效果和它的方差.然后,利用统计的元分析方法计算这些系统上的平均间接效果并判断它是否显著地区别于零.实验结果表明,不论使用哪个类规模度量进行分析,类规模对面向对象度量与易维护性之间关联关系的混和效果通常是存在的.因此,验证面向对象度量与易维护性之间关系的实验研究应将类规模视为一个混和变量.     

基于Halcon的光纤端面尺寸检测方法

针对传统光纤端面尺寸检测几何尺寸误差大、效率低的弊端,采用一种基于Halcon的光纤端面尺寸检测方法,利用数字图像处理算法,采用中值滤波的方法对图像进行预处理,消除图像噪声,并对图像进行二值化及形态学处理,选用Canny算子作为边缘检测算子确定像素级边缘,该方法边缘检测性能较好,且具有较强的抗噪声能力|再从选取的边缘中选出类圆度高的部分边缘进行共圆轮廓合并、拟合,通过拟合的椭圆和圆得到光纤半径、不圆度、同心度等几何参数。实验结果表明,纤芯和包层半径可以精确到万分之一,不圆度和同心度可以精确到小数点后8位,测量精度较高且不受操作水平影响。     

Degrees of Freedom

This article reviews several attempts to define degrees of freedom, and offers some simple explanations of how they are derived and why they are used in various contexts.