中学化学教学分层次研究性学习的实验研究

分层次研究性学习是指教师根据学生的元认知能力进行分类后,将不同层次的学生按一定比例编排分组,在教师的指导下,学生在自己具备的学习经验的基础上,以问题为导向,通过多种活动,以科学探究的方式,各司其职、互相探讨,积极主动地建构自己的知识系统,达到对知识的深层理解,建立科学概念,养成科学研究习惯,形成自己的科研方法,发展科研能力的一种学习活动.     

初中化学开展研究性学习的尝试

“研究性学习”既是一门课程,又是一种新的教与学的方式。主要从现行教科书中的研究性学习内容、研究性学习片断、化学实验中的研究性学习、化学习题中的研究性学习、化学复习中的研究性学习、化学课外研究性学习等方面介绍了在初级中学进行实践尝试的体会。     

化学教学中加强学生元认知能力的实验研究

学生元认知能力的高低进接影响其学习的质量和效率.教学实验表明在高中化学教学中应用元认知教学能提高学生的元认知能力、有效地控制学习分化、提高学生的化学学业成绩.实验说明,在教学中提高学生的元认知能力,对中等生、学困生的学习成绩的提高,效果特别显著.     

在化学新课程中培养学生元认知能力的教学策略研究

元认知理论的提出从更深层次上理解了人类学习的过程。在新课程背景下,结合元认知理论对漳州市高一学生在化学新课程学习中的元认知情况进行问卷调查,针对调查情况,研究提出了在化学新课程中培养学生元认知能力的教学策略。     

基于元认知理论的化学实验教学策略

实验是化学学习中获取知识、培养创新思维和实践能力的主要渠道。把元认知理论应用于化学实验教学实践来指导学生的学习可以解决“如何教会学生学习”及“如何提高元认知能力”等问题。对在化学实验教学中如何提高学生元认知水平提出了几点教学策略,以期元认知理论能与化学实验教学真正结合,对培养学生全面发展产生积极的影响。     

农科基础化学实验研究性教学模式的构建与实践

针对农林高校化学实验教学中存在的问题, 提出以培养学生自主学习和创新能力为教学目标, 通过优化教学内容、改革教学方法, 提高学生学习兴趣, 形成了基础实验、综合设计性实验、研究性实验和创新实验等多层次实验教学体系, 构建了农科基础化学实验研究性教学模式。这对于提高学生的学习效率, 培养学生的自主学习能力与创新能力具有重要意义。     

中学化学教学中实施研究性学习的尝试

研究性学习既是一门课程,更是一种方法。在开发研究性学习课程的同时,必须注重学科课程在教学形式和内容上向研究性学习的借鉴。本文就中学化学教学中如何实施研究性学习提出具体思路,探讨了中学化学教学中实施研究性学习 的方法、步骤。     

引入源头活水激活高三化学教学

研究性学习能提高学生分析问题、解决问题的能力和创造能力,而高三化学的实际又决定了很难让学生开展研究性学习,本文探讨了如何将研究性学习融入到高三化学复习中,如何利用研究性学习优化高三复习、提高学生能力的一些做法。     

研究性学习中学生的体验

本文通过实践、调查、反馈,对研究性学习中学生的态度,学生对研究性学习中小组、选题、老师的要求,研究性学习的意义、基本特征,在研究性学习进行的过程中需要处理好的选题、建组、管理、评价以及与必修课的关系等问题,提出了一个比较清晰的认识。     

化学教学中认知策略的教学训练

认知策略是学习者内部组织起来的调控学习、思维等活动的内部定向技能。化学教学中认知策略的教学训练要经历认知策略价值认同、认知策略尝试、认知策略反思、认知策略迁移和应用、认知策略巩固等阶段。教师要在认知策略教学训练中结合化学教学内容,渗透元认知知识,丰富学生的元认知体验,引导学生进行元认知监控,坚持群体教学与个别指导相结合,引导学生进行合作学习。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

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.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

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.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

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。