共查询到20条相似文献,搜索用时 62 毫秒
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在同课异构的教学实践中,分别通过新授课、概念课和复习课的教学设计和实施,阐述如何遵循认识发展来突破学生的认知障碍,通过教学设计、教学实施、教学评价和教学反思诠释"为什么教""教什么""怎么教""教得怎么样"和"教学发展"的问题,凸显教学的本质。 相似文献
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基于深度学习理念,以“常见高分子材料的用途与合成”为学习主题,开展关于有机合成复习课的教学实践。指出在有机合成的复习课,开展深度学习有利于激发学生的学习需求、调动学生高阶思维、让学生迁移运用所学知识。基于深度学习的教学设计需要把握挑战性学习主题、深度学习目标、深度学习活动和持续性评价4大要素。提出课前应引导学生开展挑战性学习主题的项目调研;课上应创设引导学生深度学习的问题情境,促进学生高阶思维的发展;课后应让学生以思维导图的形式理顺有机合成的一般方法等,为教师开展基于深度学习的教学实践提供参考。 相似文献
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通过分析电解池学习的知识要求和学生学习电解池知识存在的困难,从原理、装置和任务3个维度提出电解池认识模型,在此基础上设计了高二电解池复习教学,并进行了实践。结果表明基于该模型进行复习教学的设计和实施有利于提高学生解决电解池问题的能力,并在教学反思中总结了存在的不足,指明了后续教学的方向。 相似文献
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Tan‐Hao Shi Shuo Tong Mei‐Xiang Wang 《Angewandte Chemie (International ed. in English)》2020,59(20):7700-7705
Linearly fused hydrocarbon nanobelts are a unique type of double‐stranded macrocycles that would serve as not only the powerful hosts in supramolecular science but also the templates to grow zig‐zag carbon nanotubes with defined diameters. Fully conjugated hydrocarbon nanobelts such as belt[n]arenes would also possess unique physical and chemical properties. Despite the importance, both fully conjugated and (partially) saturated hydrocarbon nanobelts remain largely unexplored because of the lack of cyclization methods. Reported here is the construction of nanometer sized H12‐belt[12]arenes based on the strategy to close up all fjords of resorcin[6]arene by means of six‐fold intramolecular alkylation reactions of resorcin[6]arene derivatives. All resulting H12‐belt[12]arenes produce a very similar nanobelt core structure with six benzene rings and six boat 1,4‐cyclohexadiene rings being alternately linear‐fused to give a nearly equilateral hexagonal cylinder. The average long diagonal is around 1 nm and the height of the cylinder is about 0.3 nm. The acquired H12‐belt[12]arenes would be the potential precursors to various hydrocarbon nanobelts including fully conjugated belt[12]arenes. 相似文献
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A. V. Akopyan R. A. Fedorov B. V. Andreev A. V. Tarakanova A. V. Anisimov E. A. Karakhanov 《Russian Journal of Applied Chemistry》2018,91(4):529-542
Papers published in the past decade on oxidative desulfurization of hydrocarbon raw materials using hydrogen peroxide, oxygen, and ozone as oxidants, and also using ultrasonic treatment and adsorption and extraction methods for separating the oxidized sulfur-containing compounds are summarized and systematized. 相似文献
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W. Cooper 《European Polymer Journal》1975,11(12):833-839
Factors underlying the supply of raw materials and the manufacture of petrochemical-based polymers are discussed, with particular emphasis on future trends and energy consumption. Examples are given of development in monomer synthesis, e.g. for isoprene, and of recent advances in the synthesis and properties of hydrocarbon polymers, specifically new elastomers, together with the likely technological and economic impact. 相似文献
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溴加成脱烯反应用于含烯汽油单体烃及族组成的分析 总被引:3,自引:3,他引:3
提出了一种用于汽油组成分析的新方法 ,该方法采用溴加成选择性地转化并检测烯烃 ,解决了单体烃分析中的烷烯混峰问题 ,简化了识谱过程 ,由此通过一个包含极性预柱与非极性分析柱的简单二维体系或者与气相仪 (GC)联用的原子发射光谱检测器 (AED)两种途径均可进行准确度高的单体烃分析。在所选溴加成条件下 ,汽油中烯烃溴化率为 10 0 % ,而烷烃和芳烃保持惰性。处理全过程仅需 12 0s~ 15 0s ,操作简单且重复性好。该处理适用于含烯量为 0~ 10 0 % (体积分数 )的汽油 ,且主要针对含烯较高的催化裂化汽油。 相似文献
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Kendall N. Houk Yi Li Jeffrey D. Evanseck 《Angewandte Chemie (International ed. in English)》1992,31(6):682-708
Twenty-five years after the discovery of a vast class of organic reactions named “pericyclic reactions” by Woodward and Hoffmann, ab initio quantum mechanics provides a detailed analysis of the geometries, energies, and electronic characteristics of the transition structures of these reactions. Common features are found in all these reactions, and generalizations permit prediction of other transition-structure geometries and energies. At the same time, great diversity is observed—from strongly bonded, rigid, closed-shell entities to weakly interacting, flexible diradical structures. 相似文献
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