化学实验“三三三”翻转教学模式的探索与实践*

针对当前化学实验翻转课堂教学模式中存在的不足,依托“云班课”,重构了以学生为中心的化学实验“三三三”翻转教学新模式,即将实验教学划分为“三个课堂”:自学课堂、理论课堂和实验课堂等;理论课堂里包含“三个环节”:个人汇报、小组活动和测试点评等;学习效果评判有“三个评价”:自学评价、参与评价和动手评价等。以有机化学实验中“环己烯的合成”为例,采用该新的教学模式开展了教学活动,整个教学过程不仅体现了“以学定教、学生为中心”的教学理念,而且也能发挥出线下传统课堂的优势,实现了将“知识内化”的时间拉长,达到对学生线上自学“知识传授”掌握度的有力检验的目的,更有时间和空间进行课程思政元素的挖掘与融入,完成在知识传播中实现对学生的价值引领。     

突破实验室空间限制的“大学化学实验”教学实践

为了提高“大学化学实验”教学效果,在实验教学中将智能手机通过无线投屏器和投影仪连接,将实验原理讲解、实验仪器操作、纠正实验共性错误和实验安全培训等教学基元高效率地展现于课堂。该教学新模式突破了实验室空间限制,不但有助于提高指导教师的课堂时间的利用效率,而且提高了对学生的指导率和实验成绩优秀率,还培养了学生严谨的化学实验习惯。     

“思想实验”的价值及在实验教学中的实践路径*

对“思想实验”的发展历程及其在科学和技术创新活动中的意义进行了综述。提出了将“思想实验”与化学实验教学结合的启发式教学策略,优化了现行的化学实验教学流程。采用引导学生对实验步骤的设计思路进行反向逻辑推理和分析的教学方法,能够提升学生的创新思维和创新实践能力。     

增强大学生学习自我效能感的化学实验教学策略*——以“药物制剂工程实验”为例

以提高大学生化学实验积极性和实验学习效率为目标,在“药物制剂工程实验”课程中实施能增强大学生学习自我效能感的化学实验教学策略。以“乳剂的制备”实验为研究背景,设计并实施了三阶段的实验教学流程。同时,通过构建过程性评价量化指标、开展三方评价和问卷调查等形式,对该化学实验教学策略的实施效果进行了评价。通过对比实验组和对照组学生的过程性评价成绩和问卷调查结果,发现实验组平均得分大多高于对照组,说明采用了本实验教学策略的实验组学生的自我效能感高于对照组,因此,本实验中采取的提高大学生自我效能感的化学实验教学措施确实有效且具有实际意义。     

产教融合下的高职“绿色生产链”实验课程体系——以药品生产技术专业为例

实验教学是高等职业教育深化产教融合的重要部分。重庆工业职业技术学院在实施产教融合的教学改革中,对药品生产技术专业的实验课程体系进行了优化,构建了“绿色生产链”式实验课程体系,内容包括生产链式实验课程体系框架、绿色环保微量实验内容和“O2O”实验教学手段等。通过改革,实现了药品生产技术专业实验教学的“做学相融”和“产学相融”,提升了学生的综合实践技能、职业综合素养和解决实践问题的能力。     

在解密“骗局”中推广化学科普知识*

“骗局”中也蕴含着丰富的化学知识。高校科普工作者可以在解密这些“骗局”中,推广化学科普知识。围绕5W 模式--“谁来科普”“要科普给谁”“如何科普”“科普什么”和“科普效果如何”等5个问题,尝试建立一种在解密“骗局”中推广化学科普知识的新思路。具体为:以青少年和老年人为重点科普对象,构建“老师+学生”共同实施、现场演示与讲解并重、新旧媒体联合传播、“效果指标体系”评价的科普模式,实现精准化学科普的目的。     

基于启发式科学写作策略的中学化学实验教学设计——以“碱性锌锰电池”为例

以启发式科学写作策略框架指导下的教学活动为基础,结合化学实验教学的特点,构建了“五阶段”化学实验教学模式,该模式下的教学过程分为5个阶段,分别为任务准备、实验参与、合作协商、探究反思、完成书面写作,将学生的论证活动与实验活动相联系,促进学生的实验论证,结合写作促进对论证过程的反思,进一步达成对科学本身和实验原理的理解。并且结合高中化学“碱性锌锰电池”实验案例,分析启发式科学写作策略指导下的教学实施,启迪中学教师展开该策略的教学。     

一流课程建设——基础化学实验

从教学团队、课程内容、教学模式、教学条件及考核模式等方面的改革介绍了基础化学实验一流课程建设,即以开展实验教学培训、鼓励交流合作、打破编制壁垒建设实验教学团队;以科研反哺教学、开展实验竞赛、注重教材建设改革课程内容;以“讲一练二考三”“简易混合式”“思想实验”等创新教学模式培养学生创新能力;以更新仪器设备及运用信息技术改进教学条件;并通过评教机制及魅力化学实验课堂机制改革基础实验考核模式。     

面向高阶思维培养的自主型实验教学模式的设计与实践*

基于教育现代化、发展“互联网+教育”、培养创新性人才的指导思想,结合“超星学习通”网络平台与实验课堂的优势,设计了面向高阶思维培养的“预习自测-讲授讨论-自主实践-总结反思”的四段自主型实验教学模式,并应用于化学与化工类专业分析化学实验课程的教学实践。该实验教学模式增加了学生自主学习时间,培养了学生“分析、综合、评价和创造”等高阶思维能力,提高了实验课程的教学效率,为高等院校实践实验教学的改革提供了参考依据。     

剖析师生对绿色化学的认知偏差

在绿色化学思想逐渐普及的同时,发现许多学生和教师对“绿色化学“和“绿色化学实验”的认知存在偏差。学生错误地认为“绿色化学”就是任何时候都禁止排放任何废物的化学;教师错误地认为：实施绿色化学实验教学时,不能向教室或实验室泄漏一丁点废气,致使学生的嗅觉等感官体验被剥夺,造成他们对事物的感知不完整。     

Di­methyl­phenyl­sulfonium tri­fluoro­methane­sulfonate and methyl­di­phenyl­sulfonium tri­fluoro­methane­sulfonate

The bonding geometry of sulfur in the cations of the title compounds, C₈H₁₁S⁺·CF₃SO₃^? and C₁₃H₁₃S⁺·CF₃SO₃^?, respectively, is similar and is independent of the ratio of the Me/Ph substituents. As expected, in both cations, the S—Ph bonds are somewhat shorter than the S—Me bonds. In both crystal structures, the interaction between cations and anions is similar.     

Methyl­tri­phenyl­stibonium tetra­fluoro­borate

In the title compound, [Sb(CH₃)(C₆H₅)₃]BF₄, there are four independent cations and anions in the asymmetric unit. The geometry around the Sb atom is distorted tetrahedral, with Sb—C distances in the range 2.077 (4)–2.099 (10) Å and angles at the Sb atom in the range 103.3 (3)–119.0 (4)°.     

2,4,6‐Tri­chloro­phenyl­iso­nitrile and 2,4,6‐tri­chloro­benzo­nitrile

The molecular structures of the title compounds, 2,4,6‐tri­chloro­phenyl­iso­nitrile (IUPAC name: 2,4,6‐tri­chloro­phenyl isocyanide), C₇H₂Cl₃N, and 2,4,6‐tri­chloro­benzo­nitrile, C₇H₂Cl₃N, are normal. The two structures are not isomorphous, but do contain similar two‐dimensional layers in which pairs of mol­ecules are held together by pairs of Cl?CN [3.245 (3) Å] or Cl?NC [3.153 (2) Å] interactions. The two‐dimensional isomorphism is lost through different layer‐stacking modes.     

{[(N‐Methyl‐p‐toluidino)­di­phenyl­phospho­ranyl­idene]­methyl}(N‐methyl‐p‐toluidino)­di­phenyl­phospho­nium iodide

The cationic part of the homodifunctional amino­phospho­ranyl ligand, C₄₁H₄₁N₂P₂⁺·I^?, shows interesting features associated with the N—P—C—P—N skeleton. The P—C(H) bond distances [1.696 (3) and 1.697 (3) Å] possess partial double‐bond characteristics. The nature of the P—C(H) and P—N bonds suggests that the positive charge is only distributed around the P—C—P atoms. The structure has near twofold symmetry through the central methyl­ide‐C atom.     

Bis(μ‐hexa­methyl­enetetr­amine)­bis(aqua­di­bromo­cadmium)­di­aqua­di­bromo­cadmium dihydrate

The title compound, poly­[[di­aqua­di­bromo­cadmium‐μ‐(1,3,5,7‐tetra­aza­tri­cyclo[3.3.1.1^3,7]decane‐N¹:N⁵)‐aqua­cad­mium‐di‐μ‐bromo‐aqua­cadmium‐μ‐(1,3,5,7‐tetra­aza­tri­cyclo[3.3.1.1^3,7]decane‐N¹:N⁵)‐di‐μ‐bromo] dihydrate], [Cd₃­Br₆­(C₆­H₁₂­N₄)₂­(H₂O)₄]·­2H₂O, is made up of two‐dimensional neutral rectangular coordination layers. Each rectangular subunit is enclosed by a pair of Cd₃(μ₂‐Br)₆(H₂O)₃ fragments and a pair of (μ₂‐hmt)Cd(H₂O)₂Br₂(μ₂‐hmt) fragments as sides (hmt is hexa­methyl­enetetr­amine). The unique Cd^II atom in the Cd₂Br₂ ring in the Cd₃(μ₂‐Br)₆(H₂O)₃ fragment is in a slightly distorted octahedral CdNOBr₄ geometry, surrounded by one hmt ligand [2.433 (5) Å], one aqua ligand [2.273 (4) Å] and four Br atoms [2.6409 (11)–3.0270 (14) Å]. The Cd^II atom in the (μ₂‐hmt)Cd(H₂O)₂Br₂(μ₂‐hmt) fragment lies on an inversion center and is in a highly distorted octahedral CdN₂O₂Br₂ geometry, surrounded by two trans‐related N atoms of two hmt ligands [2.479 (5) Å], two trans‐related aqua ligands [2.294 (4) Å] and two trans‐related Br atoms [2.6755 (12) Å]. Adjacent two‐dimensional coordination sheets are connected into a three‐dimensional network by hydrogen bonds involving lattice water mol­ecules, and the aqua, bromo and hmt ligands belonging to different layers.     

Specific heat on Sr<Subscript>2</Subscript>Nb<Subscript>2</Subscript>O<Subscript>7</Subscript> and Sr<Subscript>2</Subscript>Ta<Subscript>2</Subscript>O<Subscript>7</Subscript>

Summary Specific heats on the single crystals of Sr₂Nb₂O₇, Sr₂Ta₂O₇ and (Sr_1-xBa_x)₂Nb₂O₇ were measured in a wide temperature range of 2-600 K. Heat anomalies of a λ-type were observed at the incommensurate phase transition of T_INC (=495 K) on Sr₂Nb₂O₇ and at the super-lattice phase transition of T_SL (=443 K) on Sr₂Ta₂O₇; the transition enthalpies and the transition entropies were estimated. Furthermore, a small heat anomaly was observed at the low temperature ferroelectric phase transition of T_LOW (=95 K) on Sr₂Nb₂O₇. The transition temperature T_LOW decreases with increasing Ba content x and it vanishes for samples of x>2%.     

Ethyl­tri­phenyl­phospho­nium perrhenate and (iodo­methyl)­tri­phenyl­phospho­nium perrhenate

Ethyl­tri­phenyl­phospho­nium perrhenate, (C₂₀H₂₀P)[ReO₄], and (iodo­methyl)­tri­phenyl­phospho­nium perrhenate, (C₁₉H₁₇IP)[ReO₄], have been crystallized from 2‐propanol. Both crystal structures consist of phospho­nium cations and perrhenate anions. The cations show the typical propeller‐like geometry. In both crystals, the positions of the nearly tetrahedral anions are stabilized by weak C—H⋯O hydrogen bonds, and for the latter compound, I⋯π interactions also occur.     

2,4‐Di­nitro­phenyl­hydrazones of 2,4‐di­hydroxy­benz­aldehyde, 2,4‐di­hydroxy­aceto­phenone and 2,4‐di­hydroxy­benzo­phenone

In 2,4‐di­hydroxy­benz­aldehyde 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­amide solvate {or 4‐[(2,4‐di­nitro­phenyl)­hydrazono­methyl]­benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate}, C₁₃H₁₀N₄O₆·C₃H₇NO, (X), 2,4‐di­hydroxy­aceto­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­am­ide solvate (or 4‐{1‐[(2,4‐di­nitro­phenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate), C₁₄H₁₂N₄O₆·C₃H₇NO, (XI), and 2,4‐di­hydroxy­benzo­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­acet­amide solvate (or 4‐­{[(2,4‐di­nitro­phenyl)hydrazono]phenyl­methyl}benzene‐1,3‐diol N,N‐di­methyl­acet­amide solvate), C₁₉H₁₄N₄O₆·C₄H₉NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent mol­ecule.     

Chemical durability of MoO<Subscript>3</Subscript>-P<Subscript>2</Subscript>O<Subscript>5</Subscript> and K<Subscript>2</Subscript>O-MoO<Subscript>3</Subscript>-P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

Thermal and chemical durability studies of the phosphate glasses belonging to the binary MoO₃-P₂O₅ and the ternary K₂O-MoO₃-P₂O₅ systems are reported. The chemical resistant attack tests carried out on the free alkaline MoO₃-P₂O₅ glasses show that the glass associated with the P/Mo ratio 2 has the high chemical durability. It shows also a high glass transition temperature value. The above findings are interpreted in terms of the cross-link density of the glasses and the strength of the M-O bonds (M=P, Mo). The influence of K₂O addition on the properties (density, T _g, durability) of this binary high water resistant glass is studied. It is found that the chemical durability along with the other physical properties are reduced by the incroporation of K₂O in the glass matrix. The results were explained by assuming the formation of non-bridging oxygens and weak bonds. The mechanism of the dissolution of these glasses is proposed.