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随着现代信息化技术的快速发展,微课在高职教育教学中发挥了重要作用,但也存在许多的问题。本文分析了微课在高职教育教学中的作用,探讨了微课在高职教学中存在的问题,并对微课的应用提出一些建设性的意见或建议。 相似文献
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分析化学是化工专业的专业基础课。本文在混合式教学的基础上,以自制的分析化学微课与雨课堂的教学实践为例,对基于微课与雨课堂的混合式教学进行了初步的探索。文章设计了基于微课与雨课堂的混合式教学活动,并进行了相关的问卷调查,并对存在的一些问题进行了试探性的回答。希望本文的研究能为基于网络资源与在线教学辅助工具的混合式教学提供一些参考。 相似文献
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我国微课教学和化学史教学一直以来存在着诸多问题。基于微课平台进行化学史教育,不仅有利于推动微课建设,更有利于将我国化学史教学推向更高水平。文章结合微课和化学史教学的共性和个性给出了三条具体理由:(1)化学史有利于解决微课中的情感缺失问题;(2)微课的多媒体形式和短小新颖特点,能使化学史更好地应用于课堂中,有利于改变传统化学史教学的边缘化地位;(3)微课有利于集中一两个化学史的知识点学习,学生更易理解和掌握。实现上述三点,需要基于二者共性和个性进行整体的化学史微课教学设计,并给出化学史微课教学设计"空气组成的发现"具体案例,以期推动我国化学史微课教学走向新台阶。 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile
Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, 13C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc. 相似文献
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The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu3Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu3Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters. 相似文献
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《国际聚合物材料杂志》2012,61(1-4):113-122
Abstract Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed. 相似文献
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G. R. Hamed 《The Journal of Adhesion》1983,16(1):31-39
A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength. 相似文献
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责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体. 相似文献
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Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method1 was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity. 相似文献