“物质的量”教学中学生认知建构探微

本文以现代认知心理学的学习理论，分析了学生对“物质的量”进行有意义学习的条件，并试图揭示出学生学习过程中的认知建构机制。     

化学教学中认知策略的教学训练

认知策略是学习者内部组织起来的调控学习、思维等活动的内部定向技能。化学教学中认知策略的教学训练要经历认知策略价值认同、认知策略尝试、认知策略反思、认知策略迁移和应用、认知策略巩固等阶段。教师要在认知策略教学训练中结合化学教学内容,渗透元认知知识,丰富学生的元认知体验,引导学生进行元认知监控,坚持群体教学与个别指导相结合,引导学生进行合作学习。     

论化学教师教学认知的基本图式

教师的教学认知支配着教师的教学行为和专业发展。教师教学认知图式的丰富性体现了教师的专业发展水平。教师的教学认知图式具有3个层次：第1层次是要素性教学认知图式,包括对教学内容的认知、学生已有知识或经验的分析、学习目标的设计、作业设计、教学基本思路的形成、学习主题设计、教学活动设计以及教学反思等8个基本要素;第2层次是内容类型教学认知图式;第3层次是具体内容的教学认知图式。     

凸显学科价值的教学重难点突破策略——分子结构

新课程背景下，通过探索“分子结构”主题的“学科背景下的学习问题挖掘”和“发展具备学科特质的学习活动”教学策略，促进学生学习方式的转变，有效突破认知难点，发展学生的化学学科核心素养。     

样例学习用于化学符号技能教学的实践研究——直链烷烃系统命名的学习

以普通高中高一年级学生为研究对象,研究样例学习中采用正误样例学习、提升正误样例变异性对学生测验成绩和认知负荷的影响。实验结果表明：高变异正误样例组的测验总成绩显著高于正确样例组;在近迁移测验中,采用正误样例学习、提高正误样例变异性无法显著提高测验成绩;在远迁移测验中,高变异正误样例组测验成绩显著提升;正误样例学习相比正确样例学习可以有效降低学习认知负荷。建议在化学符号技能教学中采用高变异正误样例学习,可有效提升学生测验成绩;积极采用正误样例学习降低学生认知负荷。     

化学平衡的信息化教学工具研究——以合成氨为例

针对现行化学平衡教学中存在的突出问题，研发了一款以合成氨为例的化学平衡知识学习和习题验证的教学软件。该软件采用了可视化的技术，用柱状图、曲线、数据来展示反应达到平衡的动态变化过程，便于学生从反应平衡的图像和数据中获取信息并进行推理，从而认知化学平衡的原理。该软件不仅能用于化学平衡各概念的教学，也能为化学平衡习题课的讲解创设必要的教学情境。     

化学教学情景设计中的策略与方法

创设教学情景的主要目的是为了激发学生的兴趣和启发思维.兴趣是构成学习心理的动力系统中情感、意志的最活跃因素,也是目前化学教学中较为薄弱的方面.     

深入研究,促进少数民族学生化学学习的发展--畲族学生化学学习中非智力因素影响的调查与分析

论文对我国少数民族畲族学生进行了化学学习中非智力因素影响的调查与分析，从基本情况、化学学习动机、化学学习兴趣、化学学习习惯、化学学习意志等5个方面作了调查，对其特征和问题作了分析，提出了促进畲族学生化学学习发展的教学建议。     

利用“姆潘巴效应”改进氢键教学

教学设计要重视实验探究的作用，以问题驱动课堂教学，从原有知识和现有知识的认知冲突中，策划高质量的学习活动。基于“姆潘巴效应”分子理论说，以“热水与冷水谁先结冰”为探究主题，以验证“姆潘巴效应”实验为主线，引导学生从分子水平的角度分析“姆潘巴效应”。通过将氢键理论贯穿到整个教学过程中，丰富氢键教学实践，让学生体验科学探究的过程，从而搭建宏观物质与微观世界的桥梁。     

谈认知结构理论对化学教学的启示

现代认知结构理论认为,学生的认知结构是影响其认识世界、进行高效学习的决定性因素,主要表现在学生的策略性知识、知识的表征和知识的组织3个方面。化学教学要帮助学生建立良好的认知结构,使其完备化、条件化,使化学知识结构化。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.