“素养为本”的化学课堂教学*——以“原子晶体”为例

基于“素养为本”视角,以“原子晶体”的教学为例,对教学主题内容、教学现状及学情进行分析;以发展学生化学学科核心素养为主旨确定教学目标;以“微粒-微粒间的相互作用-物质的聚集状态-物质性质”的认识思路为主线,以“模型认知,建构概念-证据推理,归纳性质-微观探析,探究结构-科学史实,揭示价值”的任务型教学流程,达到落实并发展学生化学学科核心素养的目的。     

指向“证据推理与模型认知”的教学设计——以“原子结构模型的演变”为例

以“原子结构模型的演变”为例,以化学史实为情境,设计环环相扣的问题,引导学生在分析证据及建构并评价模型的过程中体会实验证据与模型建构及演变之间的关系,认识模型在物质结构理论建立过程中的重要作用及其发展性特征。该教学设计在学生对原子模型的理解上具有显著效果。     

基于“教、学、评”一体化的深度学习*——以“气压变化在化学实验中的应用”复习课为例

以气压变化在化学实验中的应用为切入点进行复习。以密室逃脱游戏为情境,通过装置气密性的检查归纳气压改变的原因及其导致的现象,构建处理化学实验中气压变化情况的一般模型;通过改进仪器控制反应发生和停止来强化模型;利用模型分析并改进教材中测定空气中O₂含量的经典实验;利用模型设计实验证明CO₂和NaOH溶液反应的发生。这些学习任务的设计突出了实验探究,促成了模型构建,培养了学生的创新意识,实现了深度教学、发展核心素养的目的。     

基于思维模型建构的“物质检验”初中复习教学研究

以让学生自主建构物质检验的思维模型为目标设计教学,通过完成物质检验的探究任务,学生自主建构思维模型,形成完整的思路,从而提高解决此类问题的能力。并在北京某中学初三年级进行教学实践,对教学实施效果进行了检验,根据教学实践总结出建构“物质检验”思维模型教学的有效教学策略：基于建模历程与生活情境选择素材;以学生为中心自主建构“物质检验”思维模型,引导学生经历多样化的思维发展过程;学生经历不同层级进阶的模型建构历程。     

“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。     

基于结构化认识和解决物质转化问题的思维模型建构*——以“氢氧化钠变质的实验探究”为例

以探究氢氧化钠变质为依托点,融合酸、碱、盐相关知识,在复习知识的同时,将结构化认识和解决物质转化问题的思维方法贯穿于课堂实验探究始终,帮助学生从“概念理解-模型建构-学习活动-真实问题-模型评价”5个维度,体验模型认知的具体过程。利用实验探究的手段解决学生的认知冲突,修正和完善模型,实现结构化认识和解决物质转化问题的思维模型建构,提升化学学科核心素养。     

发展“模型认知”素养的教学实践*——以“化学方程式”为例

模型认知是重要的思维方法。基于模型认知进行教学设计,能促使教师从关注知识转向关注核心素养,从而使教学活动有效地促进学生思维能力的发展。在对模型及模型认知理解的基础上,以典型的符号模型“化学方程式”为例,阐明了教学思路和教学活动与学科观念的关系,形成了发展学生模型认知核心素养的教学设计。     

生活境脉促体验 实验创新助探究—指向核心素养发展的“铁及其化合物的应用”教学实践

有机融合学生生活中的经验与体验和化学学习中的认知与思维,可优化课堂进程,提高学习效率,让化学知识建构的过程同时成为化学学科核心素养发展提升的过程。在“铁及其化合物的应用”的教学中,以“笔·墨”为情境生成真实问题,在互动、探究、体验中整合物质性质,建构思维模型,并应用模型解决问题,发展科学探究、证据推理、模型认知等化学学科核心素养。     

基于模型认知与手持技术的化学能与电能项目式教学*——以“设计不同类型的化学电源”为例

以“设计不同类型的化学电源”为项目主题,详细介绍了项目的确立、规划、实施。系列学习活动包括:原电池基础知识教学,建构与应用原电池认知模型,分组设计不同类型的化学电源,进行电流影响因素的探究实验,运用手持技术数字化实验测量电池电流大小,开展成果交流汇报等。课题源于生活,有助于学生深入理解化学能与电能之间的相互转化,提升化学兴趣,发展化学核心素养。     

课程思政视角下化学思维型课堂的建构*——以“乙醇”的教学为例

通过以真实问题为情境,以化学知识结构化与化学核心观念为基础,以问题的探究为路径,以乙醇教学为例,建构了课程思政视角下的化学思维型课堂即“两思课堂”的基本教学模型,探索了“两思课堂”的评价方法与内容。通过分析学生表现可知两思课堂能同步实现核心价值培育与化学学科核心素养培养,有效实现化学学科的育人价值。     

Alumina-supported iron catalyst - long-term study of the light product distribution in Fischer-Tropsch synthesis

Several models have been proposed to describe the carbon number product distribution and mechanism in Fischer-Tropsch synthesis (FTS). However, these models have not fully explained the product distribution and mechanism owing to the wide range and complexity of hydrocarbons in FTS. This study was conducted based on the Yao and Anderson-Schulz-Flory (ASF) carbon number product distribution models for light (C₁–C₆) hydrocarbon products of a Fe/Al₂O₃ catalyst. The product distribution based on the molar ratio of olefin to paraffin (O/P) and the neighboring olefins was also studied in order to better understand the mechanism in FTS and C₂ olefin deviation during FTS.Two sets of experiments (A and B) with different reaction conditions were conducted in microtubular fixed-bed reactors on the Fe/Al₂O₃ catalyst for 2249 h and 360 h, respectively. We found that the α values from the Yao and ASF carbon number product distribution models are relatively similar. The α values from the Yao carbon number product distribution plots are relatively constant, irrespective of the reaction conditions.Interestingly, it was also found that the secondary reactions of the C₂ olefin by re-adsorption to produce paraffins and long-chain olefins are dependent on the CO conversion and the reaction temperature during the FTS. Also, the product distribution of the neighboring olefins during the reduction condition gave a similar trend to what was observed for other reaction conditions. This result confirmed what was observed in the Yao and ASF carbon number product distribution of the olefins.     

Macroscopic solvation of molecules in excited states: An MCSCF model including solvent polarization effects-I

An MCSCF model including the effects of solvent polarization is developed. The model is applied within the limitations of INDO approximations to look into the dominant effects of solvent polarization on the electronic structure in the excited states of a model system (e.g.nπ ^* states of H₂CO). Important features of macroscopic solvation-induced reorganization of electron density and some consequence thereof are noted.     

量子化学模型方法在机械力化学中的应用

机械力化学作为一种无需溶剂的绿色化学技术得到广泛关注。然而,机械力化学反应机制需要从原子和分子尺度上深入理解力诱导的化学反应。在过去的20年中,量子化学模型方法在机械力化学机理研究中得到广泛应用,高精度量化计算可得到外力下变形分子的几何结构、能量、过渡态等诸多性质。本文介绍了目前机械力化学领域的主流量子化学模型的基本原理,同时也关注了这些模型方法在软件上的具体实现,并借助典型的案例阐述了量子化学模型在解释机械力化学机理中的作用与价值。     

非线性和时变参数时间序列模型及其在水质分析中的应用

时间序列分析是根据观测值建立数学模型，研究数据的内在规律，现有文献主要是介绍线性时间序列模型。研究表明化学分析数据很多涉及非线性时间序列，且具有时变参数特性。本文在研究线性、非线性时间序列模型基础上，提出一种具有时变参数特性的非线性时间序列模型。该模型用于加酸调ｐＨ的循环冷却水系统进行预报，可使ｐＨ值极差降低３～６倍，对保证水质稳定具有重要意义。     

Nonlinear Dependence of Fish Bioconcentration on n-Octanol/Water Partition Coefficient

Abstract

The log-log relationship between the bioconcentration tendency of organic chemicals in fish and the n?octanol/water partition coefficients breaks down for very hydrophobic compounds. The use of parabolic and bilinear models allows this problem to be overcome. The QSAR equation log BCF = 0.910 log P - 1.975 log (6.8 10^?7 P + 1) - 0.786 (n = 154; r = 0.950; s = 0.347; F = 463.51) was found to be a good predictor of bioconcentration in fish.     

蛋白质离子交换平衡模型

本文综述了蛋白质的离子交换平衡模型的研究进展，包括Langmuir模型、质量作用模型以及建立在双电层理论基础上平行板模型和表面过剩模型，分析比较了各模型的特点和存在的问题，对今后的研究方向进行讨论。     

Measurement and correlation of the solubility of genistin in eleven organic solvents from T = (283.2 to 323.2) K

The solubilities of genistin in pure solvents including tetrahydrofuran, acetone, ethyl acetate, acetonitrile, isopropanol, n-butyl alcohol, methanol, cyclohexane, n-hexane, chloroform and ethanol were determined by the high performance liquid chromatography (HPLC) analysis method at T = (283.2, 293.2, 303.2, 313.2 and 323.2) K. The fusion enthalpy of genistin was estimated by the group contribution method. The solubility data of genistin were correlated by the simplified thermodynamic model, the modified Apelblat model, λh model and NRTL (Non-Random Two-Liquid) model. The calculated values by all models were in good agreement with the experimental values and however, the NRTL model could give better correlation results than other three models.     

Simplistic modeling approach to heterogeneous dilute-acid hydrolysis of cellulose microcrystallites

The classic kinetic model for cellulose hydrolysis is often referred to as pseudo-homogeneous, a term revealing the insight that the process is actually heterogeneous. During the past 10–15 yr, the shortcomings of this model have been demonstrated in various studies and the interest in the heterogeneous aspects has increased. The present work presents a simplistic model in which the intrinsic, heterogeneous hydrolysis and transport rates are coupled by the assumption of a constant glucosidic surface concentration. The mechanisms affecting these two rates are largely unknown, but the model serves as a guideline for further exploration of the process.     

Reactive Distillation: An Attractive Alternative for the Synthesis of Unsaturated Polyester

Summary: Unsaturated polyester is traditionally produced in a batch wise operating reaction vessel connected to a distillation unit. An attractive alternative for the synthesis of unsaturated polyester is a reactive distillation. To value such alternative synthesis route reliable process models need to be developed. In this paper, the strategy is described for the development of the reactive distillation model. Essential parts of the reactive distillation model are kinetic and thermodynamic which are subsequently validated with the experimental data of the traditional batch process such as acid value of the polyester, weight of the distillate and glycol concentration in the distillate. We find that the models predict these important variables reliably. Unsaturated polyester production time is around 12 hours in the traditional batch process. However, the simulation study of the reactive distillation process shows that the total production time of unsaturated polyester in a continuous reactive distillation system is between 1.5 hours to 2 hours for the same product quality as during batch production. The equilibrium conversion is raised by 7% compared to the traditional batch process. The model demonstrated that reactive distillation has the potential to intensify the process by factor of 6 to 8 in comparison to the batch reactor.