《高分子物理》互动教学法的实例——橡胶网络理论

《高分子物理》是高分子专业本科生教学中的重难点。本文展示了橡胶网络理论的教学过程,介绍一种互动式教学方法。橡胶弹性理论中,通常用仿射变形来描述橡胶交联网的变形,即交联点按与橡胶试样的宏观变形相同的比例移动。但是,人们对于物理交联是否存在仍有争议,于是提出了交联网的相邻网链可以相互横切的幻象网络模型。通过让学生预先对仿射网络和幻象网络模型进行调研,然后进行课堂讲解的方法,让学生更深刻地掌握橡胶网络理论中的难点。这种方法让学生很好地理解知识点,具有良好的教学效果。     

《高分子物理》课程中结合碳纳米管的案例教学研究

碳纳米管分子结构、性能与传统的液晶高分子材料具有非常多共性之处,是《高分子物理》课程教学中极具代表性的学科前沿教学案例。本文以碳纳米管为案例教学对象,从结构、物理和力学性能以及溶液相行为等方面,对碳纳米管与棒状刚性结构液晶高分子材料进行类比;在此基础上,将教学知识点延伸至借鉴芳纶纤维等液晶纺丝技术制备高取向度碳纳米管纤维的新方法,并对比分析碳纳米管纤维与有机纤维性能特点。通过合理设计课程主线、优选教学内容,培养学生的自主学习、学科交叉创新能力,激发学生学习的能动性,提高授课效果和教学质量。     

非高分子专业《高分子化学与物理》教学中的几点体会

高分子科学已渗透于各个领域与学科,形成了一个无法替代的交叉学科,因此,工科化学或材料相关专业纷纷开设高分子相关课程。《高分子化学与物理》作为哈尔滨工程大学材料化学专业的主干课之一,包括高分子化学和高分子物理两个侧面,其中高分子化学部分侧重高分子合成的基本理论知识,高分子物理部分则侧重于高分子的结构与性能。本文分析了高分子化学与物理的课程特点,总结了在课堂教学中采取的行之有效的措施和教学尝试,介绍了在课堂教学过程中,如何导入心理教育,提高学生的学习兴趣。     

高分子材料课程的讨论与互动式教学

浙江大学《高分子材料》课程针对高分子专业本科生开设,教学内容包含了塑料、橡胶、纤维等主要的传统高分子材料以及聚合物共混材料的相关内容。该课程的特点是知识点多而分散、知识面宽,而内容相对陈旧。采用讨论与互动式教学,将老师讲授与学生讲授相结合,由学生组成学习小组,具体分配到某一种高分子材料的教学内容。学生课后收集和整理相关资料,制作幻灯片并在课堂上完成讲授以及问题解答。通过课程结束后的调查问卷收集学生反馈,说明该方法能够较好地完成教学内容,极大地调动学生的积极性,提高了学生参与课程讨论和学习的热情。     

链段的讨论

无论是在聚合物的结构部分 ,还是在聚合物的性能部分 ,链段 (Ｓｅｇｍｅｎｔ)这一术语出现在《高分子物理》教科书的始终。初学者抓住这一点 ,将大有益处。1　一种特殊的运动单元　　高分子材料品种繁多 ,性能千变万化。有的柔软而富有弹性 ,可作为橡胶使用 ;有的质地坚硬 ,几何尺寸稳定 ,可作为塑料、结构材料使用 ;有的可纺丝、成膜 ,可作为纤维和薄膜使用。高分子材料之所以具有不同于低分子材料的这些独特的性能 ,是因为高分子运动的复杂性。　　高聚物多层次的微观结构影响了它的分子运动 ;而聚合物的性能 ,特别是力学性能又是高聚物分…     

高分子材料支化结构与流变性的联系串讲北大核心CSCD

高分子链结构为直链型或支化型以及高分子支链的形态、多寡和长度对材料的剪切黏度、黏流活化能、熔体破裂现象等流变性能有显著影响,且与高分子材料成型加工行为密不可分。本文以串讲方式讨论了高分子材料支化结构与流变性能之间的联系。理解、串并、归纳和总结高分子支化结构与流变性之间的联系有利于使学生更加深刻领会《聚合物流变学》课程中高分子材料结构与性能间的关系,串联高分子物理、聚合物流变学、高分子材料成型加工系列专业课程知识。     

基于“基础促进创新，实践推动科研”的《材料结构与性能》课程教学改革探索与实践

《材料结构与性能》是一门研究高分子的多层次结构、分子运动和物理机械性能之间的课程。结合《材料结构与性能》课程的特点,本文分析了《材料结构与性能》课程的现状和存在的问题,提出了“基础促进创新,实践推动科研”的教学改革思路,即从思维导图、理论教学与实验教学相融合角度,实现抽象高分子物理理论的具象化,夯实基础;依据国家重大需求和实际应用案例,通过主题讨论翻转课堂,提高学生批判和质疑思维,分析和解决问题能力,为高分子材料的创新性学术研究提供指导。     

高分子物理课程知识体系的构建革新

高分子物理是高分子材料相关专业的专业基础课,内容丰富,章节间关系复杂,课程主线往往不容易把握。本文从运动对高聚物性质(性能)的决定性作用角度,提出了构建高分子物理课程知识体系的观点:在高分子结构部分,充实原子、键等部分作用的论述,完善高分子结构划分的层次;明确高分子不同结构层次都具有运动与变化能力的认知,重点突出不同高分子结构运动、变化的特征和规律;根据根据每一个结构层次运动特征,综合理解结构、结构的变化对高分子性能的影响。     

高分子材料支化结构与流变性的联系串讲

高分子链结构为直链型或支化型以及高分子支链的形态、多寡和长度对材料的剪切黏度、黏流活化能、熔体破裂现象等流变性能有显著影响,且与高分子材料成型加工行为密不可分。本文以串讲方式讨论了高分子材料支化结构与流变性能之间的联系。理解、串并、归纳和总结高分子支化结构与流变性之间的联系有利于使学生更加深刻领会《聚合物流变学》课程中高分子材料结构与性能间的关系,串联高分子物理、聚合物流变学、高分子材料成型加工系列专业课程知识。     

高分子物理教学中“结晶”概念的讲解

高分子物理是高等院校高分子材料与工程专业的一门重要的专业基础课。"结晶"是高分子聚集态结构中重要的概念。巨大的分子量及长链状分子结构使高分子的结晶过程与小分子相比愈加复杂。在高分子物理课程的教学过程中,通过一定的逻辑架构向学生介绍结晶与有序、链柔性、玻璃化温度之间的关系并串联与结晶相关的一些概念(如结晶度、结晶温度、熔点以及结晶速率),使学生在初学阶段对高分子晶态结构建立起科学的认知体系。实践证明,通过这种教学方式,绝大多数同学都能较好地理解并掌握这部分教学内容。     

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.     

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。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

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.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

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.     

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^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。