小学四年级学生对平均数概念理解的发展过程

利用Pirie和Kieren提出的数学理解发展模型,分析了3名小学四年级学生对平均数概念理解的发展过程.结果表明:学生对平均数概念的理解经历了初步了解、产生表象、形成表象、关注性质和形式化等5个水平.在理解发展过程中,当学生发现他的思想和行动与自己所面临的问题不一致时,他就要折返回内层水平来扩展自己目前的活动能力和活动空间.而教师的干预则激发了学生的折返,为学生提供了独立建构或修正个人表象的机会.     

从意象的数量问题看意象的浑整性

国内有学者提出"一句一个意象"的说法。此种说法有待商榷。形成这种说法的缘由在于重视读者视域中的意象而忽视作者视域中的意象,重视了西方"二元对立"思维模式下的意象观而忽视了中国古代文论中意象的浑整性。     

武广客运专线路基A、B组填料施工技术

结合武广客专的现场实践,主要详细介绍A、B组填料的施工程序、质量控制要点和最佳机械组合,有一定的借鉴意义.     

Precision measurement of the Newtonian gravitational constant

The Newtonian gravitational constant G, which is one of the most important fundamental physical constants in nature, plays a significant role in the fields of theoretical physics, geophysics, astrophysics and astronomy. Although G was the first physical constant to be introduced in the history of science, it is considered to be one of the most difficult to measure accurately so far. Over the past two decades, eleven precision measurements of the gravitational constant have been performed, and the latest recommended value for G published by the Committee on Data for Science and Technology (CODATA) is (6.674 08 ± 0.000 31) × 10⁻¹¹ m³ kg⁻¹ s⁻² with a relative uncertainty of 47 parts per million. This uncertainty is the smallest compared with previous CODATA recommended values of G; however, it remains a relatively large uncertainty among other fundamental physical constants. In this paper we briefly review the history of the G measurement, and introduce eleven values of G adopted in CODATA 2014 after 2000 and our latest two values published in 2018 using two independent methods.     

求解非线性互补问题的两步迭代-Filter方法

利用牛顿迭代法作为预测步,用不动点迭代法作为修正步,结合filter技术,提出了求解非线性互补问题的两步迭代-filter算法,并证明了算法的局部三阶收敛性,最后通过数值实验表明该算法的有效性.     

宜宾市九座古戏楼考述——《酒都文物——宜宾市第三次全国文物普查成果集成》补遗

尽管宜宾市第三次全国文物普查全面而仔细,"全市乡村普查到达率均达到100%",但笔者对宜宾市戏曲文物调查时,又查出九座古戏楼,它们分别是江安县底蓬镇古戏楼、江安县蟠龙镇古戏楼、江安县桐梓镇禹王宫古戏楼、江安县夕佳山民居古戏楼、长宁县桃坪乡玉皇楼古戏楼、长宁县梅硐镇余家祠堂古戏楼、珙县洛表镇何家大院两座古戏楼、长宁县老翁镇文昌宫古戏楼。以上戏楼具有丰富的历史文化价值,笔者实地测量了相关数据,并采访相关人士发现了因把握文物的标准不同、建筑保存现状很差等原因造成这九座戏楼被普查遗漏了。     

“宁为鸡口,无为牛后”的语言文字浅析

"宁为鸡口,无为牛后"影响深远,而其研究尚有余地,以《读书杂志》和北大语料库为基础,从语法、异文和文化三方面进行探讨,其中,异文是重点,希望对词源考据和语言应用等有所裨益。     

基于一般家庭用的智能烹调锅设计

烹调是一门学问,普通人如果没经验,没技巧是无法烹调出一手好的佳肴。总结炒菜的三大秘诀是:火候控制,均匀翻炒,抛空受气。厨师能够烧一手好的佳肴,正是因为他们掌握了这三大秘诀。设计的目的就是要根据炒菜的三大秘诀研制出一款能够自动实现烹饪的锅具,实现让普通人不经学习都能烧一手大厨般的佳肴。且该款锅具还能够符合当今的时代要求:低炭、节能、环保。     

Social media use in the career development of graduate students: the mediating role of internship effectiveness and the moderating role of Zhongyong

This paper proves that social media use can contribute in important ways to employability outcomes. Specifically, results from a survey of 196 recent graduate students in China indicate that social media use is positively related to employability skills. Internship effectiveness serve as a mediating mechanism through which social media use affects employability skills. Zhongyong has a moderating effect on the social media use-internship effectiveness relationship. In addition to the direct moderating effect, Zhongyong is found to moderate the indirect relationship between social media use and employability skills. We discuss implications of these results for research and practice.