促进学生认识发展的教学案例研究项目对教师教学行为的影响

教学行为研究是当前教师教育研究的热点,教学行为转变的研究是教学行为研究的重点。通过促进学生认识发展的教学案例研究项目,分别从备课行为、课堂教学行为、课后反思行为3方面对教师的教学行为转变进行研究,利用课堂观察、录像分析、调查问卷、访谈对教师教学行为转变的结果及其原因进行统计分析,概括提炼出具体教学案例研究中促进教师教学行为改变的有效策略。     

基于项目学习的高中化学教学设计与实践*——以“探究食品脱氧剂中的化学问题”为例

以“探究食品脱氧剂中的化学问题”为项目学习主题,以探究食品脱氧剂的主要成分、脱氧原理、能量转化形式为项目学习活动,呈现了基于项目学习的高中化学教学设计思路、教学流程,进行了项目教学实施,并结合前后测、学生自评互评和教师评价量表从知识、能力、素养等方面分析了实施项目教学后的效果。     

项目教学法在高职医学化学教学中的应用

通过对目前高职医学化学教学课堂使用项目教学法情况的调查和分析,发现教师和学生的热情已经有所降低,有相当一部分教师、学生感觉项目教学法的优势目前很难显现出来。据此调查分析其中原因,提出了7项措施用以改善目前的窘状。     

新手熟手初中化学教师课堂教学行为特征的比较研究*——以“酸和碱”单元教学为例

通过对新手化学教师和熟手化学教师各4节“酸和碱”单元常态课堂中教师使用教学行为链、教学行为对在时间和频次等方面的特征进行对比分析发现,在教学行为链上,新、熟手化学教师都会在较高水平的教学行为链上花费更多的时间,熟手化学教师高水平教学行为链在频次上的占比要优于新手化学教师,在不同教学行为链时间安排上的合理性要更高一些;在教学行为对上,新、熟手化学教师都多以“问”和“讲”,学生多以“答”的方式来展开课堂活动,熟手化学教师在每一次“动”和“思”上所用时间要明显高于新手化学教师,学生参与课堂的水平上,熟手化学教师要优于新手化学教师。得出如下启示:与熟手化学教师相比,新手化学教师应有效地组织和安排课堂教学行为,注重对“酸和碱”学科内容本身及其教学的驾驭。无论是熟手还是新手化学教师均应进一步给予学生课堂参与的机会。     

初中化学“水的净化”的项目式教学——以“设计净水系统”为例

以“设计净水系统”为项目主题,介绍了项目教学主题选取、项目目标确定、项目规划、实施与评价策略。项目教学中,关注学生认知与思维发展,随着净水系统的设计、制作、测试和再设计项目学习活动的展开,引导学生综合运用化学、物理、数学等多学科知识方法分析解决问题,促进学生提炼真实情境下“物质分离与提纯”解决思路,发展化学学科核心素养,同时体验和感受完整的工程设计过程。     

促进学生建立认识角度的化学课堂教学行为研究

为了探寻促进学生建立认识角度的有效教学行为，构建了由教学环节、教学子环节和具体教学行为等3个维度构成的分析框架，选取有代表性的教学课例，依据分析框架对教学课例进行编码。通过深入对比分析优秀常规课例与促进学生建立认识角度的课例的教学行为，得到了促进学生建立认识角度的有效教学行为。     

基于真实情境的项目式教学在高三复习课的应用——轧钢厂废水分析处理

针对高三学生在解题和解决实际问题中缺乏对知识的整合和系统运用这一问题,围绕真实情境下的轧钢厂废水分析处理展开项目式教学。通过引导学生剖析项目任务中的化学知识和化学问题,以铁及其化合物的知识作为主线复习内容,将高中化学多个模块的知识进行结构化整合。拓宽学生认识化学问题的角度和深度,促进学生学习的热情和思维方式的转变,让化学学科核心素养得到落实。     

基于认识模型建构与应用的化学教学设计*——“水溶液中的离子反应与离子平衡”一轮复习课

分析了“水溶液中的离子反应与离子平衡”主题内容,通过学生前测发现学生对这一部分内容的认识存在着认识水平较低、认识不够深入等问题。针对这一问题,在实际教学中通过构建水溶液中的离子反应与离子平衡认识模型的方式,创设真实的问题情境,引导学生明确任务类型、丰富认识角度、形成认识思路,从而使学生对主题内容的认识走向深入和系统。通过后测,分析了教学效果,进行了教学反思,为在教学实践中开展认识模型建构教学提供参考。     

高中化学线上教学课堂提问与课程标准的一致性分析*——以上海市“空中课堂”为例

以上海市“空中课程”中高中化学X教师的线上课堂教学为例,采用SEC一致性分析模式,从核心素养的“证据推理与模型认知”这一视角,对其课堂提问与课程标准的一致性进行了分析。研究表明:(1)从总体上看,X教师的课堂提问与课程标准中的素养之间具有较好的一致性;(2)X教师的课堂提问在证据推理素养层面上与课程标准一致性程度欠佳,而在模型认知层面上与课程标准具有较好的一致性;X教师的课堂中根据具象证据或模型进行推理论证的问题多于课程标准中的素养要求,根据抽象证据进行推理论证的问题较少;(3)从素养水平维度分析,X教师课堂中低素养水平的问题占较大比例,高素养水平的问题少于课程标准要求;(4)上述偏差的产生主要受线上教学的影响,另外还受到考试要求、教师个人对课程标准的理解等因素的影响。     

化学理论课堂教学结构模型构建初探——基于课堂教学视频案例分析的研究

模块化结构的我国中学化学课程标准和新教材,需要寻求教学规律与课堂教学的组成、结构模型来支持课程目标的实施,将课堂教学视频案例研究作为新的研究方法,成为关注的热点。研究采用了课堂教学视频案例采集和教学结构维度的分析方法,选取了6个优秀化学理论课堂教学视频案例,应用“Videograph”视频分析软件从学生学习行为、教师教学行为和师生互动3个主要维度对案例进行分析、解读与比较。对教师课堂导入、新内容讲授（区分为教师启发式讲授和教师直接知识讲授）、师生课堂探究（区分为教师演示实验探究和学生自主探究）、师生课堂探究讨论（区分为学生小组探究讨论、师生互动问答讨论）、课堂练习、课堂小结、其他活动等7个部分进行了编码分析和特征解读。初步提出了化学理论课堂教学结构的时间模型。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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%).