第一届网络课程大赛 Recognition of Polymer secondary structure situation2task2-2.ppt

In order to characterize polymers, therefore, we use the molecular weight distribution (MWD) curve, which represents a plot of the percentage (frequency) of a particular species against its molecular weight (Figure 2.4) 【18】. 因此，为了表征合成高分子，我们使用相对分子质量分布曲线，这 个曲线表示了某一特定分子的百分含量（概率）与相对分子质量的关系（图2.4)。 Situation 2 Task 2 Recognition of Polymer secondary structure(2)molecular weight Summarization 本篇需要掌握的单词Words: tensile adj. 拉伸的，拉力的。tensile strength 拉伸强度 compressive adj. .压缩的，有压缩力的。compressive strength 压缩强度 modulus n. 模量，模数 impact v. n. 冲击，影响。impact strength 冲击强度 viscosity n. 黏度 polydispersity 多分散性 gel permeation chromatography (GPC)凝胶渗透色谱 Situation 2 Task 2 Recognition of Polymer secondary structure(2)molecular weight Summarization 本篇需要掌握的句子: However, the unique properties exhibited by polymers and the difference in behavior between polymers and their low-molecular-weight analogs are attributable to their large size and flexible nature. Beyond this MW or DP, there is a steep rise in the performance until a certain level, beyond which the properties change very little with increase in molecular weight (Figure 2.3). Situation 2 Task 2 Recognition of Polymer secondary structure(2)molecular weight Summarization 本篇需要掌握的句子: Consequently, unlike biological systems, synthetic polymers do not consist of identical molecules, but represent a mixture of many systems each of which has a different molecular weight. Situation 2 Task 2 Recognition of Polymer secondary structure(2)molecular weight Homework1 Preview Task3 Recognition of Polymer tertiarystructure (1)secondary bonding forces Situation 2 Task 2 Recognition of Polymer secondary structure(2)molecular weight * Review configuration n. (分子）构型；（设备）配置 conformation n. 构象 stereoregularity n. 立构规整性 isotactic adj. 全同立构的，等规立构的 syndiotactic n. 间同（立构）的，间规（立构）的 atactic adj. 无规立构的 Review Configuration — Arrangement fixed by primary valence bonds; can be altered only through the