大学有机化学“五维度”教学新策略——以“芳烃的亲电取代和亲核取代反应”为例

介绍了大学有机化学“强理念、重思维、活课堂、共育人、乐钻研”五维度教学新策略的内涵与实践。以线下教学为主,腾讯会议和慕课为辅助,践行“有机化学是科学也是艺术”的教学理念;采用多循环“疑探式”教学方式,辨析亲电试剂和亲核试剂的多样性;注重培养学生多种科学思维的综合运用;强化“文献预习”“练习讲解”“综合作业”“师生互动”等多个教学环节,加深学生对知识的理解与应用,提升学生在课堂中的参与度,着重培养学生的科学思维和人文素养、自主学习与团队合作精神。     

人教版高中化学必修模块教科书实验活动的分析与比较*——以2019年版教科书“实验”和“实验活动”栏目为例

以人教版高中化学必修模块教科书(2019年版)“实验”和“实验活动”栏目的实验活动为研究对象,采用Herron修正的“实验活动探究层次分类法”(LOLA)和笔者提出的“学生实验行为要求分类法”(RSBLA)对其进行分析,并与2007年版教科书进行对比。研究发现,2019年版教科书的实验活动探究层次处于层次1和层次2,学生行为要求为“观察”“记录实验现象”“回答与实验有关的问题”和“设计实验”。卡方检验表明,2019年版教科书和2007年版教科书“实验”栏目的实验活动探究层次分布比例和学生实验行为要求均存在显著性差异。     

国际科学教育视角下1-9年级学生“物质”核心概念进阶维度研究

概念转变理论、认知架构理论、概念形成理论都验证了核心概念建构的重要性。基于核心概念建构的进阶路径,介绍了学生理解“物质”概念进阶表征框架、“物质”和学生能力水平进阶表征框架、“物质”结构的学习进阶表征框架、“物质”核心概念区块理论表征框架和“物质”概念描述理论表征框架,并以“水的认识”为例分析了其构造图和结果空间。基于美国、英国、澳大利亚、爱尔兰、新加坡、加拿大阿尔伯塔省、加拿大安大略省、中国台湾、中国大陆9个国家或地区1至9年级科学课程文件,梳理了学生“物质”核心概念,并从“成分与辨识”“性质与应用”“变化与转化”3个视角划分了学生“物质”核心概念进阶维度,介绍了“物质”核心概念进阶测量方法,以期对我国科学教育有所启示。     

以“位构性”模型建构和学科能力发展的必修“原子结构 元素周期律”教学设计和实践*

在高中必修阶段“原子结构 元素周期律”主题已有研究的基础上,将“位构性”系统模型与学科能力活动任务相结合,提出了本研究的理论框架,进行了单元整体的教学设计并实施。通过预设学生的表现水平,设计各课时的评价任务,过程性地诊断学生在各个课时中“位构性”模型建构与学科能力的发展水平,描述学生在本章学习过程中的发展变化,促进了学生“证据推理与模型认知”等核心素养的发展。最后,归纳出以“位构性”模型建构和学科能力发展的“原子结构 元素周期律”在教学实践中的有效策略。以期能够对日后开展“原子结构 元素周期律”主题的教学设计与实践能够提供参考和建议。     

高中生“芳香烃”心智模型的测评及其教学启示*

采用二阶式纸笔测验以及半结构化访谈法对高中生持有的“芳香烃”心智模型进行测评,并重点分析了学生建构的与“芳香烃和苯的同系物的概念”“芳香烃的结构”“苯及其同系物的化学性质”等概念群相关的缺陷模型。研究发现学生建构的有关“芳香烃”缺陷模型包括3大类共计11种;学生对有机物空间结构的想象力和建构能力较为薄弱;学生对“有机化合物结构内基团之间相互作用对其化学性质的影响”认识不足,“性质结构”模型不完善;学生建构的有机化学的心智模型尚不具备整体性。     

基于变构学习模型的高中化学“导致悖论”教学设计*

“导致悖论”教学是一种智在创境、妙在引领的教学,其核心理念源自于变构学习模型的悖论思想,给学习者创造一个“肯定→否定→肯定”的反思性学习过程。高中化学教学设计可以通过4种途径分别创设“概念与概念”相悖、“理论与实验”相悖、“理论与理论”相悖和“实验与实验”相悖的悖论情境,最终实现学生新旧概念的更替和高阶思维能力的发展。“导致悖论”教学在实施中要注意精选合适的知识内容,加强学生心理的调控,提供丰富的支撑材料。     

日本初中理科教科书中“粒子的存在”内容组织与呈现特征

从“主要观念”“核心内容”“重要问题”“情境活动”等4个方面自上而下对日本的《新科学》教科书中“粒子的存在”相关内容的组织与呈现进行分析，发现其具有注重内容结构化和学生认识进阶性，以科学探究活动引领，“粒子模型”显性化等特征。     

“原电池”的项目式教学*——探究“水动力”盐水灯发光之谜

以“菲律宾能源救星”创设探究情境,以“水动力”盐水灯发光之谜展开项目式学习探究设计之旅,在项目任务推进中对“水动力”盐水灯的原理和影响因素展开深入探究,重建学生对原电池的模型认知;设计并制作“家庭版”水动力灯,最终回归到指导抗震减灾等社会场景中去,加强学科与真实情境的结合与应用,锻炼和提升学生的科学精神与社会责任感,发展学生的化学学科核心素养。     

中美高中化学教科书“化学反应原理”模块微观表征插图的设计分析

微观表征插图是重要的化学教学素材,是学生对三重表征在头脑中加工内化的重要认识媒介。为了能在“化学反应原理”模块教学中更好地发挥微观表征插图的价值,通过内容分析法,对中国人教版高中化学教科书和美国高中化学教科书Chemistry: Concepts and Applications在此模块的微观表征插图设计进行了比较分析。结果显示,2种版本教科书中的微观表征插图在该模块插图总数中的占比较少,呈现最多的主题内容均为过程微观表征;缺少“化学反应的方向、限度和速率”主题的微观表征插图;2者表征的形式水平较高,但美版教材更好地融合了“宏、微、符”3类表征。最后,基于分析结果对教科书“化学反应原理”模块中微观表征插图的设计与使用提出了相关建议。     

在解密“骗局”中推广化学科普知识*

“骗局”中也蕴含着丰富的化学知识。高校科普工作者可以在解密这些“骗局”中,推广化学科普知识。围绕5W 模式--“谁来科普”“要科普给谁”“如何科普”“科普什么”和“科普效果如何”等5个问题,尝试建立一种在解密“骗局”中推广化学科普知识的新思路。具体为:以青少年和老年人为重点科普对象,构建“老师+学生”共同实施、现场演示与讲解并重、新旧媒体联合传播、“效果指标体系”评价的科普模式,实现精准化学科普的目的。     

关于能量最低原理的误读——论“凭什么相信计算”之二

不要把能量最低原理与核外电子填充规则混为一谈,后者仅仅是能量最低原理众多应用中的一例。体系"能量越低越稳定"的说法错在忘了它成立的前提:熵固定。Gibbs的说法才是能量最低原理的完整表述,它等价于Clausius的最大熵原理,两者各自有其成立的前提条件。由Gibbs能量最低原理可以导出核外电子的填充规则。宏观和微观世界只有一个能量最低原理。     

Is There a Minimum Electrophilicity Principle in Chemical Reactions？

For 25 simple reactions, the changes of the hardness （△η）, polarizability （△α） and electrophilicity index （△ω） and their cube-roots （△η^1/3, △α^1/3, △ω^1/3） were calculated. It is shown that although the Maximum Hardness and Minimum Polarizability Principles are not valid for all reactions, but in most cases △ω^1/3〈0, whereas we always find △ω〈0. Our observation implies to this fact that for those chemical reactions in which the number of moles decreases or at least remains constant, the most stable species （reactants or products） have the lowest sum of electrophilicities. In other words ＂the natural direction of a chemical reaction is toward a state of minimum electrophilicity＂. This fact may be called Minimum Electrophilicity Principle （MEP）.     

Recent advances in microfluidic cell sorting techniques based on both physical and biochemical principles

Microfluidic technologies for isolating cells of interest from a heterogeneous sample have attracted great attentions, due to the advantages of less sample consumption, simple operating procedure, and high separation accuracy. According to the working principles, the microfluidic cell sorting techniques can be categorized into biochemical (labeled) and physical (label‐free) methods. However, the inherent drawbacks of each type of method may somehow influence the popularization of these cell sorting techniques. Using the multiple complementary isolation principles is a promising strategy to overcome this problem, therefore there appears to be a continuing trend to integrate two or more sorting methods together. In this review, we focus on the recent advances in microfluidic cell sorting techniques relied on both physical and biochemical principles, with emphasis on the mechanisms of cell separation. The biochemical cell sorting techniques enhanced by physical principles and the physical cell sorting techniques enhanced by biochemical principles, are first introduced. Then, we highlight on‐chip magnetic‐activated cell sorting, on‐chip fluorescence‐activated cell sorting, multi‐step cell sorting and multi‐principle cell sorting techniques, which are based on both physical and biochemical separation mechanisms. Finally, the challenges and future perspectives of the integrated microfluidics for cell sorting are discussed.     

A Theoretical Study on Chapman Rearrangement

Some Chapman rearrangements are investigated using HF and B3LYP methods combined with two different basis sets (6‐31G** and 6‐31++G**) and both finite difference model and Janak's approximation. It is shown that although minimum polarizability (MPP) and maximum hardness (MHP) principles are always valid in these reactions, minimum electrophilicity principle (MEP) is followed just when DFT method (B3LYP) is used. The Morrel's rules are also successfully applied in predicting the validity of MEP in these rearrangements. Therefore, it seems that in the study of this kind of reaction, the results of DFT are more reliable than those of HF.     

现代元素周期律的化学微观视角探析*

由门捷列夫元素周期表到现代元素周期律的发展,将人们的关注点从元素化学性质相似性的宏观考量转移到原子电子组态周期性递变的微观探析上来。对原子核外电子排布“构造原理”的产生、发展及其作用展开讨论,尝试对元素周期律的微观本质进行探析。     

The Pauli Principle and Chemical Bonding in Molecules and Solids

The starting point of this contribution is a discussion of the concept of exchange interactions and its relation to chemical bonding and valence. Then, a class of phenomena characterized by weak chemical bonding (?1eV) in solids and molecules is analyzed in more detail, with “superexchange” in insulating solids with paramagnetic 3d-cations serving as prototype. A model of “effective electrons” is developed for weak bonding on the basis of exchange perturbation theory, taking full account of the Pauli principle. The model is applied to: (i) magnetic interactions in solids (interaction energy 10^?2 to 10^?4 eV); (ii) stability of noble-gas halides (binding energy ≈ 1eV); and (iii) rotational barriers in simple molecules (barrier heights of several 0.1 eV).     

On the generality of a cosmological speculation based on Heisenberg's principle

In a previous work [Hernández-Bermejo, B. (1996) Heisenberg's principle: A cosmological speculation, Speculations in Science and Technology, 19, 253], it was speculated that the lack of homogeneity of the large-scale structure of the universe may be due to quantum fluctuations of space in the early universe. This was argued for a Friedmann-type universe for which both the curvature and the cosmological constant were zero. Here it is shown that the same considerations are valid for arbitrary values of the curvature and .     

DEDUCTION OF QUASILATTICE WITH FIVE-FOLD SYMMETRY AND PARTICLE FRACTAL STRUCTURE MODEL

In the structure of quasicrystal, the coordination icosahedron has long ordering but no translation ordering. The author dealt with the building principle ofquasicrystal and thought that two principles played a certain role in the quasicrystal structure, i.e. the icosahedron principle and the golden mean principle. We obtained the most simple.structure model of quasicrystals, and could explain all details of the high-resolution electron microscopic image of the A1-Mn quasicrystal based on the two principles. The author's model has the characteristic of fractal structure, therefore, we call it the particle fractal structure madeh The author has made a systematic deduction of quasicrystal point group, forms, possible type of quasicrystal lattice.