基于建构主义和反省思维的实验教学——以“丁达尔现象的再认识”为例

以"丁达尔现象的再认识"教学为例,设计一系列"非常规胶体实验"创设教学情境,打破学生思维惯性,基于建构主义和反省思维,探索培养学生学科思维的教学模式。     

发展学生认识角度和深度的化学教学转变——以“化学反应原理”模块为例

以"化学反应原理"模块的4课为例,从分析"化学反应原理"的模块功能出发,探讨了发展学生认识角度和深度的教学转变.这些转变包括:(1)转变教学目标取向,从传授具体性知识为本转向建构学科核心观念;(2)转变对学科本体知识的认识,从忽视学科本体知识的内涵到深入挖掘学科本体知识内涵;(3)转变学生观,从笼统关注学生转向对学生已有认识及认识发展点的深度关注;(4)转变教学素材定位,从追求多样化、有新意向匹配教学功能定位、匹配学生认识发展层级、实现教学功能最大化转变;(5)转变对思路外显重要性的认识,从忽视思路外显重要性转变为通过多次外化促进思路外显;(6)转变学案设计方式,从填空式学案转变为过程引导式学案.     

基于学科观念的“同课异构”比较分析——以“溶液的配制及分析”为例

对"基于学科观念的化学教学"研讨主题下"溶液的配制及分析"的9节"同课异构"进行了比较分析。以学科观念的构建为教学的基本价值取向,依赖一定的情境载体,形成清晰的教学思路,让学生在理性思维中逐步深化知识和形成观念是教学设计的关键。     

围绕“化学元素观”展开深入学习——以“水的组成”教学为例

"化学元素观"是中学化学的核心观念之一。阐述了对初中阶段"化学元素观"的理解,分析了"水的组成"在"化学元素观"认识方面的重要价值。以"水的组成"教学为例,就如何围绕"化学元素观"展开深入学习进行了探讨。要发展学生对"化学元素观"的认识,需要立足学科整体的高度,以"化学元素观"为统领,思考具体知识的教学对物质及其化学变化等学科基本问题的渗透与落实,将化学观念教学具体化。     

基于STEAM教育理念的氯及其化合物的教学设计——“为某日化企业设计84消毒液的生产工艺”项目

STEAM代表科学(Science)、技术(Technology)、工程(Engineering)、艺术(Arts)、数学(Mathematics),STEAM教育理念强调打破学科的界限,培养学生的综合素养。本文以"氯及其化合物"的教学为例,用STEAM教育理念指导教学实践,构建基于化学学科的STEAM课程模式。(1)基于真实情境解决实际问题的教学,以真实情境为驱动。     

在化学教学中以Blending Learning为理念尝试"双主-探究"教学模式的研究与实践

阐述了以Blending Learning为教学理念,通过构建学科教学网站实施"双主—探究"教学模式的研究。"Blending Learning"是当前国际教育理念发展的最新动向。而在教学中实施教师主导作用和学生主体地位的有机统一、以学生自主探究为主线的教学模式,是我们在经历了对传统教学模式的批判与继承及对建构主义教学理论的发扬与引申后建立起的一种科学的教学模式。     

提升教学魅力,打造一门好课——《材料表面与界面》教学改革探索

《材料表面与界面》为高分子材料与工程专业复合材料方向的限选课。本课程对于学生奠定学科基础、培养学生对复合材料方向的兴趣具有重要的先导作用。笔者以"提升教学魅力,打造一门好课"为改革目标,充分贯彻了"教学内容是教学魅力的根本,教学方法与教学手段是将教学内容高效转化为教学魅力的催化剂"这一指导思想,从教学内容与教学方式两方面进行改革。从教学反馈看,这些改革措施能够改善教学效果,提高学生学习效率,得到了学生的认可。     

“生命活动的物质基础”复习课教学与反思

利用"营养快线"饮料建构了"生命活动的物质基础"复习课,让学生体验食品中的化学,再到生活中的化学,最后到自然界中的化学,感悟化学是无处不在的。同时,在复习课教学中,利用化学实验手段、化学思维方式和化学符号向学生展示了化学学科特色,渗透了"化学观"教育,培养了学生的学科素养,在收获知识的同时提升能力。     

基于“5+2”模块的化学教学论课程体系研究与教学实践

化学教学论是研究化学教育教学规律及其应用的学科,是高师院校学生综合实践必修课。结合基础教育课程改革,介绍了江西师范大学进行"5+2"模块的化学教学论课程体系研究与教学实践。     

铁及其化合物专题复习教学设计

1指导思想和理论依据以《北京市普通高中新课程化学学科教学指导意见》为参考,根据课程标准所确定的"课程强调学生的主体性",要"有助于学生主动构建自身发展所需的化学基础知识和基本技能"的课程性质,本节课的教学设计主要体现2方面的思考。     

Influence of the composition of carriers based on ZrO<Subscript>2</Subscript> and Al<Subscript>2</Subscript>O<Subscript>3</Subscript> on the properties of cobalt-containing catalysts on the selective reduction of NO with methane

A series of cobalt-containing granulated and structured catalysts based on zirconium and aluminum oxides has been studied. The optimum composition of binary oxide samples (80% ZrO₂ − 20% Al₂O₃) for the selective reduction of nitrogen monoxide with methane (84% conversion of NO achieved at 320 °C) has been determined. The activity of the structured catalysts depends on both the composition of the secondary carrier (ZrO₂, Al₂O₃, and their mixture) and on the nature of the skeleton of the cellular structure (cordierite, kaolin-aerosil). __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 4, pp. 237–241, July–August, 2007.     

Effect of the production temperature on the structure of Si<Subscript>3</Subscript>N<Subscript>4</Subscript> nanofibers

The effect of the production temperature on the morphology and structure of Si₃N₄ nanofibers was investigated. It was shown that nanofibers produced in the temperature range of 1340–1360°C are amorphous while those produced at 1380°C and above are monocrystalline. Apart from the principal phase (α-Si₃N₄) the imide Si₂N₂NH was also found in the reaction products.     

Studies on the Constituents of Paris Formosana Hayata Part II

Methyl palmitate (I), methyl stearate (II), stigmasterol (III), β-sitosterol (IV), (O -acyl)-β-D -glucopyranosyl-(1→3)-stigmasterol (V), (O -acyl)-β-D -glucopyranosyl-(1→3)-β-sitosterol (VI), β-D -glucopyranosyl-(1→3)-stigmasterol (VII), β-D -glucopyranosyl-(1→3)-β-sitosterol (VIII), β-D -ecdysone (IX), diosgenin-3-α-L -rhamopyranosyl-(1→2)-[α-L -arabinofuranosyl-(1→4)]-β-D -glucopyranoside (X), diosgenin-3-O -β-chacotrioside (dioscin) (XI), and diosgenin-3-O -α-L -rhamnopyranosyl-(1→4)-α-L -rhamnopyranosyl-(1→4)-[α-L -rhamnopyranosyl-(1→2)]-β-D -glucopyranoside (XII) were isolated and characterized from the stems of Paris formosana Hayata (Liliaceae).     

Effect of the Side‐Chain‐Distribution Density on the Single‐Conjugated‐Polymer‐Chain Conformation

The spatial arrangement of the side chains of conjugated polymer backbones has critical effects on the morphology and electronic and photophysical properties of the corresponding bulk films. The effect of the side‐chain‐distribution density on the conformation at the isolated single‐polymer‐chain level was investigated with regiorandom (rra‐) poly(3‐hexylthiophene) (P3HT) and poly(3‐hexyl‐2,5‐thienylene vinylene) (P3HTV). Although pure P3HTV films are known to have low fluorescence quantum efficiencies, we observed a considerable increase in fluorescence intensity by dispersing P3HTV in poly(methyl methacrylate) (PMMA), which enabled a single‐molecule spectroscopy investigation. With single‐molecule fluorescence excitation polarization spectroscopy, we found that rra‐P3HTV single molecules form highly ordered conformations. In contrast, rra‐P3HT single molecules, display a wide variety of different conformations from isotropic to highly ordered, were observed. The experimental results are supported by extensive molecular dynamics simulations, which reveal that the reduced side‐chain‐distribution density, that is, the spaced‐out side‐chain substitution pattern, in rra‐P3HTV favors more ordered conformations compared to rra‐P3HT. Our results demonstrate that the distribution of side chains strongly affects the polymer‐chain conformation, even at the single‐molecule level, an aspect that has important implications when interpreting the macroscopic interchain packing structure exhibited by bulk polymer films.     

Solvent effects on the absorption spectrum of the perylene-SbCl<Subscript>5</Subscript> complex

The perylene-SbCl₅ complex is characterized by two absorption maxima, whose positions depend on the nature of the solvent. The maximum in the region of 19×10⁻³ cm⁻¹ corresponds to the perylene cationic form and depends on the medium polarity, while another, in the region of 14×10⁻³ cm⁻¹, corresponding to the perylene-SbCl₅ complex, is governed primarily by the ability of the solvent to the electrophilic solvation. However, the quantitative generalization of the data on the frequencies of absorption maxima is only possible using multiparameter equations that take into account various properties of the solvents.     

Influence of the Cation on the Solubility of CO<Subscript>2</Subscript> and H<Subscript>2</Subscript> in Ionic Liquids Based on the Bis(trifluoromethylsulfonyl)imide Anion

Experimental values for the solubility of carbon dioxide and hydrogen in three room temperature ionic liquids based on the same anion—(bistrifluoromethylsulfonyl)imide [Ntf₂]—and three different cations—1-butyl-3-methylimidazolium, [C₄mim], 1-ethyl-3-methylimidazolium, [C₂mim] and trimethyl-butylammonium, [N₄₁₁₁]—are reported between 283 and 343 K and close to atmospheric pressure. Carbon dioxide, with a mole-fraction solubility of the order of 10⁻², is two orders of magnitude more soluble than hydrogen. The solubility of CO₂ is very similar in the three ionic liquids although slightly lower in the presence of the [C₂mim] cation. In the case of H₂, noticeable differences were observed with larger mole fraction solubilities in the presence of [N₄₁₁₁] followed by [C₄mim]. All of the mole-fraction solubilities decrease with increasing temperature. From the variation of Henry’s law constants with temperature, the thermodynamic functions of solvation were calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry’s law constants from appropriate smoothing equations, is always better than ±1%.     

Effect of the phase composition of the starting mixture on the formation of the layered perovskite-like compound Bi<Subscript>7</Subscript>Fe<Subscript>3</Subscript>Ti<Subscript>3</Subscript>O<Subscript>21</Subscript>

The effect of the phase composition of the starting mixture on the formation of the layered perovskite-like compound Bi₇Fe₃Ti₃O₂₁ in the Bi₂O₃-TiO₂-Fe₂O₃ system is reported. The rate-limiting process in the formation of this compound is reactant mass transfer to the reaction zone.     

Effect of Synthesis Conditions on the Formation of the CuCrAlO<Subscript>4</Subscript> Spinel Structure

The effect of synthesis conditions of mixed hydroxy compounds (coprecipitation mode, residence and aging times, precipitator nature) on the structural characteristics of CuCrAlO₄ spinels is studied. Evolution of the spinel structure during the solid-phase synthesis is analyzed.