《聚合物成型加工》课程教学改革初探

<聚合物成型加工>作为本科院校高分子材料与工程专业的必修专业课程,在教学过程中要坚持理论教学和实践教学两手抓,既要使学生掌握一定的理论基础,又要培养学生的实践应用能力.针对本校的培养"应用型人才"的培养方针,围绕聚合物成型加工课程的理论基础,我们在实践教学体系改革的过程中,改变了原有独立的、缺乏直接联系的实验内容,建立...     

高等中医药院校《物理化学》网络教学平台的建设与实践

《物理化学》对高等中医药院校药学类专业学生来说,是必需学习和掌握的一门综合性、抽象性和实验性较强的课程,为此建设并开展实施了《物理化学》网络教学平台。该平台主要通过在线学习和在线测试辅助理论课和实验课教学,借助平台可图文并茂地展示复杂的理论知识点,可弥补实验设备条件的不足,更生动、形象、准确地向学生教授知识,具有较强的实用性和人性化特征,对于学生后续专业课程的学习以及培养学生的科研能力等方面发挥积极影响。     

基于“学习金字塔理论”的物理化学实验教学模式改革实践

介绍了东北林业大学物理化学实验课程教学中基于"学习金字塔理论"进行教学模式改革实践的情况。在实施实验教学过程中,通过增加"学生通过在线实验视频预习""学生为学生讲解实验""操作前学生小组讨论"和"操作后学生小组总结讨论"等学习环节,建立了一种有效的"以学生为中心"的实验教学模式,促进了学生综合素质和创新能力的培养,取得了良好的教学效果。     

基于PBL的物理化学实验混合教学模式的设计与实践

依托自建物理化学实验在线开放课程及网络教学资源,在物理化学实验课程中开展了线上线下混合式教学."以问题为导向,以学生为中心"设计课程教学,开展探究式学习和过程性评价.通过课前线上预习、线下课堂教学和课后答疑指导等环节,实现了学生能力的进阶式培养,提高学生的自主学习能力、综合能力和创新能力.为高等学校实验类课程线上线下混合式教学模式的探索提供了范式.     

《聚合物成型加工》实践教学体系改革

从教学内容、教学方法、实验实践环节、考核方式等角度,深入分析了《聚合物成型加工》课程的教学现状,并在此基础上指出,目前单纯的理论教学与人才培养目标相悖,缺乏系统性的实验实践教学体系和多样化的课程考核方式。《聚合物成型加工》实践教学体系改革本着培养应用型人才的原则,从实际生产问题和研发前沿问题入手,由原来单纯的课堂教学模式改为课堂教学与实践环节相结合;考核也改为"书面作业+调研报告+项目答辩+实践操作+考试"的综合考核形式;并设计了系统性的创新实践环节,使学生在掌握课程所学基础知识的同时,可以独立的根据制品性能和使用要求,进行合理的聚合物成型物料配制,选择合适的成型加工方法,利用实验室及产学研实践基地的加工条件自己动手将聚合物原材料做成制品。     

"XXT完全线上"教学模式在分析化学课程中的实践与思考

本校分析化学教学团队采用学银在线平台(Xueyinonlineplatform)、学习通(Xuexitong)与腾讯会议(Tencent meeting)三结合的"XXT完全线上"教学模式,成功开展了分析化学课程在线教学。该教学模式既充分发挥了已有在线课程资源的作用,又提供了丰富的教学活动。实践证明,"XXT完全线上"教学打破了教与学的时空限制,为有效实施在线教学提供了参考。     

讨论式教学模式在《高分子化学》课程中的应用和思考

《高分子化学》是材料学专业特别是高分子材料专业重要的基础课程,其课程内容既包含理论科学又涉及实际应用。作为一门相对年轻的学科,有些概念和理论仍处在不断完善及发展中。从以学生为"主角"的角度出发,探讨了《高分子化学》讨论式教学的内容和形式,实现理论与实验教学的无缝连接并确立了相应的评价体系。通过将"讨论式"教学模式切实有效地融入到《高分子化学》课程当中,极大地调动学生的积极性,提高学生的综合素养,为后续专业课程打下坚实的基础。     

任务型专题教学在高分子物理中的实践

为了发挥学生在教学中的主体作用,作者使用任务型专题教学在高分子物理课程的部分章节中进行了实践。将"聚合物的分子量"、"聚合物的分子量分布"、"增塑剂"、"高分子液晶"、"橡胶弹性"和"聚合物成型加工简介"等内容设计成八个不同专题。在专题任务的设计中紧扣教学大纲,并注重加强理论和应用的联系。作为对传统教学的有效补充,任务型专题教学加强了学生的课前学习环节,提高了学生的学习主动性、创新能力和协作精神。     

《聚合物共混改性》课程现状及改革建议

《聚合物共混改性》是高分子材料与工程专业的一门专业课程,具有综合性、实践性及前沿性等特点。本文根据课程的特点,结合笔者课堂和实践教学的经验,阐述了该课程目前存在的教学现状及普遍存在的问题:学生对课程学习的疲倦、授课方式单一、缺少实践、教材陈旧及考核方式不完善等,并由此从授课模式、教学内容、教学体系、考核方式多个方面提出了课程教学改革的一些见解,以期激发学生的学习兴趣,有效提高教学效果,为培养应用型、创新型人才奠定基础。     

基于视频辅助的“翻转课堂”技术在高分子化学实验课程中的应用

在《高分子化学实验》教学过程,采用"翻转课堂"的教学理念,广泛采用视频讲义辅助教学,有效提高学生主动学习的能力,增加教学的互动性,通过多元化的实验项目设计,培养学生的分析问题、解决问题的能力,深化理论教学的效果。由于"翻转课堂"教学方式的引入,提高了学生对实验项目的领悟能力,并辅助大量的引导问题,有效实现了实验教学和理论教学的统一。通过引入视频教学的特点,有效缓解了传统实验教学中,实验仪器不足,场地紧张的难题,充分提高实验设备的使用效率。综合设计《高分子化学实验》课程的实施方式和管理制度,为视频化讲义的推广积累有益的经验。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。