布卢姆与奥苏贝尔的学习理论在化学概念教学中的综合应用

布卢姆和奥苏贝尔的学习理论都侧重学校学习的研究,强调学生学习前的认知状态、学习动机、学生主动积极参与程度、学习的连续性。根据布卢姆和奥苏贝尔的学习理论的内涵,它们在化学概念教学中的综合应用可以从4个方面来探索：关注认知准备状态,选择先行组织者;把握情感准备状态,进行适当强化;明确学习要求,促进充分参与;运用反馈-纠正,延续意义学习。     

中学生化学学习归因结构调查研究

以中学生化学学习归因结构三维模型为理论框架,编制《中学生化学学习归因能力测量问卷》。该问卷由5个因子维度构成,分别是化学学习特定自我概念、化学学习情境认知、化学学习策略认知、化学学习人际认知、化学学习使能认知维度。经过理论预设、内容及项目分析、探索性因素分析、信度分析、专家效度和维度分析、验证性因素分析等过程最终形成正式问卷。问卷整体信度、效度较高,结构效度良好,可以作为中学生化学学习归因能力测量工具。     

化学学习中的认知策略

在化学学习中,学生应获得和学会应用注意策略、编码策略、理解-控制策略、问题解决策略、情感策略等认知策略,从而学会学习。     

高一学生自主性学习基本情况的调查与分析

学习理论认为,学习是学习者与学习对象之问不断地相互作用,作用的结果使学习者原有的认知结构建构成为新的认知结构。作为学习主体的学生 对学习过程高度的责任心,以及参与学习活动的主动性、积极性,即学习的自主性,将成为制约学习成败的关键因素之一。     

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。     

高三学生化学选择学习能力现状的实证研究

培养受教育者具有选择意识和科学的选择能力是培养人的主体性的重要内容,是现代教育的特征。从选择学习的心理机制出发,探究选择学习能力的本质与构成要素,以高三学生的化学学习为基础,综合运用问卷调查法、问卷测试法以及访谈法分析高三学生化学选择学习能力的现状。结果表明:相当一部分学生自主选择意识薄弱;识别选择条件能力欠缺;不能根据自身情况做出科学合理的选择学习判断;在实施选择活动过程中,不能勇敢地面对和克服学习中遇到的困难和障碍、学生认知结构不够完善、思维品质较低、算法优化意识和能力严重缺失,不能保质保量地完成学习任务;缺乏反思意识,后续学习效率低下。     

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。     

从学生学习的原态思维到最近发展区——中学化学有效认知途径探微

学习的过程是一个积极的思维活动过程,是新旧知识、经验、思维的相互作用而引发的认知结构的同化或重组。因此,因材施教从本质上讲就是因“思”施教。本文阐述了学生学习的原态思维与教学起点以及最近发展区的关系,提出化学教学应以学生的原态思维为教学的起点,搭建化学知识建构的“支架”,不断地沿着最近发展区前行,促进知识的同化或重组。     

整合FLOWMAP与SOLO分类理论的化学学习评价——以“化学平衡”为例

基于FLOWMAP和SOLO分类理论对高中生“化学平衡”认知结构进行测查并评价其学习水平,研究表明：学优生的认知结构中对“化学平衡”概念内涵的认知较为清晰和丰富;学生认知结构变量（广度、丰富度）与其纸笔测试成绩呈现显著的正相关;学生对化学平衡知识体系中6个主要概念的学习水平的差异较大,尤其对“压强因素”的认知较差;学生容易忽视化学平衡常数,并且对各影响因素进行科学推理时论证的严谨性较为缺乏,认知不全面且抽象性水平不高。     

基于学科理解的学习任务设计策略

基于学科理解的学习任务是精细化教学研究的切入点,是核心素养的落脚点。基于分析学习任务的内容、方法、情境要素,结合原电池教学案例,提出以下设计策略:对教学内容本原性、结构化地理解;分析学生认知基础和学习困难,确定学习任务着力点;任务以本原问题体现,显化认识视角;注重学习任务的教学逻辑;活动指向学生的素养发展;创造真实适切的任务情境。     

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.     

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.     

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

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.