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1.
基于Flow Map对中美4种教材"氧化还原反应"内容难度的定量统计表明,中美教材的整合广度和表征深度的差异明显,美国教材的整合广度和表征深度均明显大于中国教材,即美国教材的相关难度较小;质性评价表明,美国教材以"化学变化中的电子"为认识核心,构建了"得失氧-氧的电负性与电子得失-氧化数与电子得失"的认知脉络,采用"电负性"作为先行组织者,更多运用对比与比较、情境推理与解释等信息处理策略,整合了大量的氧化还原反应应用类的知识。  相似文献   

2.
肖笛  熊言林 《化学教育》2019,40(7):9-15
以新加坡初中化学Chemistry Matters教材为研究对象,对教材中涉及的实验案例、实验类型及数量进行了统计。结合新加坡新版科学教学大纲及PISA测试,从教材实验的内容选取、设计意图、呈现方式等方面进行分析,并对教材实验部分蕴含的核心素养进行一定程度地挖掘。研究得出:Chemistry Matters教材中实验的设置具有"内容选取彰显与时俱进,设计意图注重学以致用,呈现方式突出图表结合,活动过程强化问题引导"等特点。  相似文献   

3.
基于“宏观辨识与微观探析”核心素养,对“烃及其衍生物的性质与应用”主题下的新旧人教版教材思考类栏目进行分类和比较分析。结果显示,新教材的内容设计更贴合新课标要求,相对旧教材在素养水平分布、认识视角外显化和符号表征规范化等3个方面有显著差异。基于此,对新教材的使用提出了4点建议:转变传统认知,重视指导与评价功能;把握教材逻辑,实现认知结构化功能;注重符号表征,发挥新教材规范功能;融合优选情境,落实新教材育人功能。  相似文献   

4.
第二届国际富勒烯科学与技术多学科会议于1996年7月7口~Ic[l在英国牛津大学召开。与会代表170人,分别来自美国、英国、法国、德国、日本、中国等用个国家和地区。我国大陆出席会议8人,台湾及香港地区各2人。富勒烯的发现者H.W.Kroto、R.E.Smalley及一些活跃在富勒烯研究前沿的科学家参加了会议,并在会上做了邀请报告。大会报告ZI篇、墙展136篇。我国有大会报告1篇、墙展11篇。与首届会议相比,此次会议不但与会人数及提交的论文数量有所增加,而且在研究广度和深度方面均获得了重要进展,进一步显示出富勒烯研究是一个充满活力…  相似文献   

5.
陈莲  万莉 《化学教育》2019,40(9):19-23
科学精神是中国学生发展核心素养的重要内容之一,不同教材对科学精神的体现不同。从理性思维、批判质疑、勇于探究等3个方面对中美2种初中化学教材中"原子"内容进行对比分析,为教师对教学内容的二次加工提供建议。  相似文献   

6.
针对科学技术和国家社会发展对生物医学创新型人才的需求,依托于学校的重大项目培育和新兴交叉学科研究课题,建立了生物医学工程与化学、物理、材料、电子和医学等"理-工-医"多学科交叉科研平台。基于"以人为本""全面发展"等现代教育理念和"以学生发展为中心"的高等教育思想,通过组建跨学科的研究生导师团,多导师联合指导,夯实学生多学科基础知识,加强学生对知识的理解和使用,拓宽研究生知识广度,着力培养研究生源头创新能力,打造研究生解决多学科交叉重要问题的能力。实践表明,多学科交叉科研平台在激发研究生源头创新思维、拓展专业知识、培养工程实践能力等方面起到重要的作用。对继续完善多学科交叉的研究生培养体系建设给出了建议。  相似文献   

7.
在卤代烃的课堂教学实践中,选定1-溴丙烷为代表物,依据化学键理论并结合模型认知、实验探究等方式创新设计课堂教学,既规避和弥补按某些教材教学带来的尴尬与不足,又能突破教学难点(卤代烃消去反应原理),更能培育"宏观辨识与微观探析""证据推理与模型认知""科学探究与创新意识""科学态度与社会责任"等学科核心素养。  相似文献   

8.
以化学反应原理内容为例,对中国人教版高中化学教材和美国高中化学教材Chemistry:Conceptions and Application习题中的情境创设进行比较研究,发现2者在情境性习题的主题分布与占比、情境素材来源分布、问题与情境的融合度等方面存在明显差异。  相似文献   

9.
为了有的放矢地完成大学化学的教学,将新课程高中化学教材和大学化学教材作对比,逐一总结归纳高中化学和大学化学相联系的知识点,并介绍知识点深度、广度的差异,使大学化学教师更好地了解高中化学教材内容。  相似文献   

10.
李小峰  郑长龙 《化学教育》2021,42(17):24-31
概念转变理论、认知架构理论、概念形成理论都验证了核心概念建构的重要性。基于核心概念建构的进阶路径,介绍了学生理解“物质”概念进阶表征框架、“物质”和学生能力水平进阶表征框架、“物质”结构的学习进阶表征框架、“物质”核心概念区块理论表征框架和“物质”概念描述理论表征框架,并以“水的认识”为例分析了其构造图和结果空间。基于美国、英国、澳大利亚、爱尔兰、新加坡、加拿大阿尔伯塔省、加拿大安大略省、中国台湾、中国大陆9个国家或地区1至9年级科学课程文件,梳理了学生“物质”核心概念,并从“成分与辨识”“性质与应用”“变化与转化”3个视角划分了学生“物质”核心概念进阶维度,介绍了“物质”核心概念进阶测量方法,以期对我国科学教育有所启示。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

13.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

14.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

15.
16.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

17.
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.  相似文献   

18.
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.  相似文献   

19.
A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).  相似文献   

20.
Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO4 oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.  相似文献   

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