Y6 and its derivatives: molecular design and physical mechanism

Non-fullerene-acceptor(NFA)materials in the bulk heterojunction(BHJ)play an important role in high-performance organic solar cells(OSCs).Recently,Y-series accep...     

小学生语言文字运用能力调查

该文就南京市小学生语言文字运用能力的个案调查情况,分析归纳出目前小学生在遣词造句能力与语言表述能力两方面所存在的问题与不足,并从语文技能训练、多种能力培养、经典样本积累、基础理论研究和评测标准研制等五个方面进行分析与思考。     

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.     

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.     

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.     

Design experiments in Japanese elementary science education with computer support for collaborative learning: hypothesis testing and collaborative construction

This paper reports design experiments on two Japanese elementary science lesson units in a sixth‐grade classroom supported by computer support for collaborative learning (CSCL) technology as a collaborative reflection tool. We took different approaches in the experiments depending on their instructional goals. In the unit ‘air and how things burn’, we designed the unit where groups of students engaged in building theories on ‘how a candle stops burning in a closed jar’. In the unit ‘characteristics of various solutions’, groups of students collaboratively constructed a pH scale as knowledge artefact. In both studies, the CSCL technology was implemented mainly for facilitating collaboration between groups. Results showed that: (1) students were more likely to engage in symmetric communication (i.e. between groups as well as within groups) in the second unit, and (2) they were also more idea‐centred and more frequently shared their ideas in the second unit. The results were discussed from the perspectives of the scientific practices students engaged in and task structure.     

步进式冷床的结构分析及其现场维护

介绍了特钢厂800轧线大棒步进式冷床的结构形式及工作原理。总结了该装置使用以来由于设备安装缺陷而产生的故障,并对部分改进方案的实施性、可靠性进了的分析,并采取了相应的改进措施。     

电子工艺专业中高职衔接的单独招生考试方案的探索

高职与中职的衔接,是构建现代职业教育体系的主要内涵之一,是培养技能型人才和建立科学化教育的必然要求。确立新型独特的中高职衔接的专业培养方案,调查中职现状,确定选拔考试内容和水平,建立合理、公平、规范的招生考试方案,在单独招生选拔中职学生的过程中,是进行有益探索的重要步骤。