首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
以"PX:有机合成的巨星"的教学设计和课堂实践为例,将社会性科学议题"PX石化项目"融入高中化学有机合成教学活动中,具体论述了学生进阶学习的任务设计、有机合成流程的问题情境设置、角色扮演活动中学生的立场抉择情况,结合教学后学生对争议性议题学习过程的态度与评价及参与课堂观摩活动的教师的评价,对教学效果和学习目标达成情况进行分析。  相似文献   

2.
新课程标准明确提出化学教学要激发学生树立以化学作为专业和职业的兴趣和理想。以“污水处理厂的氮污染治理”这一社会性科学议题为例,开发了基于SSI的化学职业教学框架,确立了识别议题、评估方案、科学辩论和决策反思等4个教学环节,指导学生基于文献资料和网站了解水处理相关专业及职业,在辩论决策中树立化学领域的职业信心,根据实践结果提出3点化学职业生涯教育建议。  相似文献   

3.
以“探究食品脱氧剂中的化学问题”为项目学习主题,以探究食品脱氧剂的主要成分、脱氧原理、能量转化形式为项目学习活动,呈现了基于项目学习的高中化学教学设计思路、教学流程,进行了项目教学实施,并结合前后测、学生自评互评和教师评价量表从知识、能力、素养等方面分析了实施项目教学后的效果。  相似文献   

4.
在“氮及其化合物”教学中,利用社会性科学议题“论证重雾霾天气‘汽车限行’的合理性”,通过直面议题激发原始想法、探讨汽车尾气与雾霾是否存在关系、探讨汽车尾气是不是导致雾霾的主要原因、面对议题的科学决策的具体教学环节,促进学生掌握氮及其化合物的主要性质,建立从物质类别、元素价态视角研究物质性质及转化的思路方法,促进多个维度核心素养的融合发展。经过多轮次教学改进,结合教学实践过程及其教学效果抽提出真实情境的创设、驱动性问题的设计、课前、课上和课后3个阶段统筹安排等教学策略。  相似文献   

5.
<正>社会性科学议题是由于科学技术应用于社会所引起的争议性复杂问题。根据《义务教育化学课程标准(2022年版)》(下简称“新课标”)的要求,社会性科学议题试题理应成为中考化学试卷的重要组成部分。以2022年8个省份8份省级统一命题中考化学试卷(河北卷、河南卷、江西卷、安徽卷、陕西卷、山西卷、福建卷、海南卷)为研究对象,分析中考化学试卷中社会性科学议题试题的考查特点,为依托社会性科学议题开展化学教学提供若干建议。  相似文献   

6.
张璐  张欣  李雅萍  吉琳 《化学教育》2022,43(8):38-43
化学专业英语是大学生在专业知识学习和创新、实践能力培养过程中常常会接触和应用到的。针对化学专业英语教学过程中的学生学习动力不足、知识记忆不牢等问题,结合学生们对化学专业英语的实际应用需求,介绍了化学专业英语教学团队在探索和实践“在用中学”的专业英语课程教学新模式过程中的经验和反思。  相似文献   

7.
陈凯  黄媛媛 《化学教育》2020,41(5):104-110
近年来社会性科学议题在科学教育研究领域越来越受到重视,运用CiteSpace V,VOSviewer对Web of Science核心合集数据库收录的社会性科学议题研究的167篇相关文献进行可视化分析。从核心作者、核心研究机构、共被引文献、关键词共现等角度,客观地分析进入21世纪以来国内外社会性科学议题研究的热点主题,发现社会性科学议题与科学论证、科学素养、科学风险及决策等相关主题的研究联系密切,社会性科学议题文献主要包括课程内容、教学和学校3个层面的研究思路。在文献的知识图谱分析基础上,从社会性科学议题课程目标聚焦、教学策略应用和教学评价缺位等3个方面获得一些启示。  相似文献   

8.
吴晗清  韩洋  寇诺  易勇 《化学教育》2023,(19):15-21
结合课标,从肥料的组成分类、化工生产、作用机制、简单鉴别、环境影响等方面,对相关素材进行了解构与统整。教学实践中,应遵循知识的螺旋式进阶路径,完善学生的认知结构和思维范式;要藉以生活中的科学探究,培养学生的实践能力和创新精神;宜依托社会性科学议题的讨论,提升学生的STSE素养,从而全方位展示化学学科的真、善、美。  相似文献   

9.
叶军 《化学教育》2022,43(19):47-51
以“环氧乙烷制备工艺中的绿色化学”为项目式学习主题,以绿色化学概念学习、化学工艺中绿色化学的设计评价等为项目学习活动,探究绿色化学理念的教学设计。培养学生绿色化学意识,提升科学态度和社会责任的化学学科核心素养。  相似文献   

10.
张淑贤  商晓绪 《化学教育》2021,42(13):28-33
以“设计净水系统”为项目主题,介绍了项目教学主题选取、项目目标确定、项目规划、实施与评价策略。项目教学中,关注学生认知与思维发展,随着净水系统的设计、制作、测试和再设计项目学习活动的展开,引导学生综合运用化学、物理、数学等多学科知识方法分析解决问题,促进学生提炼真实情境下“物质分离与提纯”解决思路,发展化学学科核心素养,同时体验和感受完整的工程设计过程。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

14.
Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.  相似文献   

15.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

16.
The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

17.
Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.  相似文献   

18.
19.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

20.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号