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1指导思想与理论依据有机合成实质是利用有机物的性质,进行必要的官能团反应,生成目标产物。在前面的学习中,学生掌握了烃、卤代烃、醇、酚、醛、羧酸、酯等有机物的结构特点、物理性质、化学性质以及用途等方面的知识。 相似文献
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以牙膏的制作为主线,通过认识口腔环境、选择牙膏材料、测定主材含量、动手制作牙膏等4个项目任务,复习酸的通性,拓展酸的个性。从元素观、转化观的视角认识物质转化规律,体现物质研究的一般思路,凸显科学探究的基本过程;构建验证无明显实验现象的反应发生的思路;建立混合物中定量测定某成分的方法;总结商品设计的思路及原则;深化物质组成决定性质、性质决定用途的学科观念。呈现一节利用已学化学知识解决真实问题的案例,有效培养学生的科学态度与社会责任,发展学生的质疑能力、批判能力、证据推理能力和创新意识。 相似文献
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以高中生有机物性质认识能力的构成为指导,基于对不同版本教材为学生认识有机物性质所搭建的先行组织者的内容与功能的分析,基于对北京市丰台区学生情况的分析,阐述了为促进学生有机物性质认识能力发展,建构认识域及认识角度和思路的策略及方法。 相似文献
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本文简述中学化学中的醛酮区别反应:银镜反应;乙醛,甲醛、甲酸、甲酸酯、葡萄糖等的银镜反应;苯酚、苯胺的干扰反应。醛酮的其它鉴别方法从略。 相似文献
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介绍了“乙炔的化学性质”的教学设计思路,展现了如何利用创新实验、丰富素材和问题讨论,帮助学生理解有机物性质和结构之间的关系。主要涉及以下几个环节:(1)通过课前自主预习,从乙炔与乙烯的相似性入手,预测乙炔的性质,了解乙炔的实验室制法;(2)结合2个创新分组实验“基于井穴板的微型化气体连续制备和性质检验装置”“利用真空输液瓶、微型样品瓶和注射器的密闭气体微型反应装置”,教师和学生一起巩固了乙炔的实验室制法,验证了预测的化学性质,丰富了对乙炔性质的感性认知,发现了“乙炔不能使酸性K2Cr2O7溶液褪色”的异常现象;(3)从尝试解释异常现象入手,教师和学生一起从键能、加成比例、聚合后主链结构等多个角度探讨了乙炔与乙烯性质和结构的差异,建立起有机物官能团与性质关系的认知模型;(4)通过尝试利用模型解释2000年诺贝尔化学奖“导电高分子”和2017年度国家自然科学成果一等奖“AIE聚集诱导发光材料” 的结构、性质与应用,教师和学生一起提升了对认知模型的理解建构,感悟了科学研究的乐趣,体会化学科学在促进人类文明发展和社会进步中的重要作用。 相似文献
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《化学教育》2010,31(Z2):341-347
一直以来元素化合物的单元教学是以知识的系统性和完备性为教学目标的,然而实际的教学效果并不理想。为此本研究提出了基于学科观念建构的元素化合物单元教学设计,目的在于通过观念建构实现知识的结构化和功能化,进而提高学生解决问题的能力。以山东科技版《化学1必修》教材中"硫的转化"单元为例,本研究提出以建构"转化观"为核心的单元教学目标,研究了"转化观"有效建构的2个重要标志,即学生能够自主建构以价态和类别为横纵坐标的二维物质转化关系图,能够利用转化关系及规律解决实际问题,实现观念的工具化。研究了有效建构"转化观"的教学策略:(1)由整体到局部的策略,即先建构转化关系再利用整体结构指导学生认识重要代表物的性质,实现思维的系统化、有序化和结构化;(2)从自然现象→实验室→工业生产→环境等多角度建构和应用转化关系,以实现知识的工具化;(3)依据各课时教学内容的特点,选择开放程度适当的教学方式,保证教学的实效性。以山东科技版《化学1必修》教材中"材料家族的元素"单元为例,提出了建构"材料观"的单元核心教学目标。具体而言,就是要帮助学生建立从化学的视角认识材料的思路和角度,即认识材料的性能、加工、制备、用途等与物质性质的关系。研究确立了教学的基本思路是:以铝为载体建构基本认识框架,以铝的重要化合物为载体深化认识思路和方法,最后应用该思路和方法认识硅及其化合物的性质与相关材料问题。在教学实践的基础之上,本研究对单元教学的实效性进行了分析,提出了基于学科观念及方法建构的元素化合物单元教学设计的一般思路和方法:明确单元核心基本观念及思想方法→选择与核心观念相匹配的知识载体→合理分配各部分知识载体的功能→合理设计单元中每一课时的教学情境、问题和学生活动→精心设计课时之间的衔接。 相似文献
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多环芳二酐型聚酯亚胺膜的透气性能李悦生,丁孟贤,徐纪平(浙江大学高分子科学与工程研究所,杭州,310027)(中国科学院长春应用化学研究所)关键词聚醚酰亚胺,聚酯酰亚胺,膜,透气性通常的聚酰亚胺加工性能较差,在芳环二酐的苯环间引入醚键等柔性基团后,其... 相似文献
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Wenbi Guan 《International journal of environmental analytical chemistry》2013,93(6):679-691
A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg?1, the maximum residue level of European Union for quizalofop-p-ethyl). 相似文献
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微量元素与疾病诊断治疗的研究现状及展望 总被引:8,自引:0,他引:8
对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述,包括:微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。 相似文献
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The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R2UPh type and -thioureas of the R2TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments. 相似文献
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Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB5型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。 相似文献
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Charles Manzi-Nshuti 《Polymer Degradation and Stability》2007,92(10):1803-1812
In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer. 相似文献
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Prof. Inmaculada García‐Moreno Lu Wang Prof. Angel Costela Dr. Jorge Bañuelos Prof. Iñigo López Arbeloa Prof. Yi Xiao 《Chemphyschem》2012,13(17):3923-3931
Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission. 相似文献
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Peter Kis Eva Horvthov Elika Glov Andrea ev
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ov Veronika Antalov Elena Karniov Potock Vladimír Mastihuba Mria Mastihubov 《Molecules (Basel, Switzerland)》2021,26(24)
Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection. 相似文献