基于合作学习的化学课堂导学

阐述了基于合作学习的化学课堂导学,应适时地在学习目标处、概念关键处、认知冲突处、知识衔接处、实验失败处、思维障碍处和课堂生成处给学生引导和帮助。     

新课程标准实施后化学学习兴趣的评价和培养

利用兴趣积分调查量表对222名初三学生进行调查,评价基于新课程标准的教学实施前后初三学生化学学习兴趣水平的差异,半定量地评价化学课程标准实施以来初三学生化学学习兴趣水平,并探讨培养化学学习兴趣、提高化学学习兴趣水平的方法和途径。     

"同分异构体"错误概念的调查与分析

同分异构体是有机化学中的一个重要化学概念。通过问卷调查,发现学生头脑中存在着许多错误概念,而错误概念对学生学习有机化学产生严重的障碍。在教学中,教师应根据教学实际,及时纠正学生头脑中的错误概念,从而提高教学质量。     

民办中学学生学习化学主动性及其影响因素的调查研究

通过对河北省唐山地区和石家庄地区的6所民办中学的837名学生进行问卷调查,及对该调查结果进行统计处理,揭示了民办中学学生学习化学主动性的现状,分析了影响学生主动学习化学的因素以及影响因素与化学学习主动性的关系。在此基础上,为民办中学化学教师优化教学、培养学生学习化学的主动性提出了一些教学建议。     

新课程背景下高中生化学学习障碍调查及成因分析

为了解高中生化学学习障碍程度,采用问卷调查的方式在湖北省武汉市2所省重点中学展开调查,从“教材原因”“教师原因(教学策略、评价策略)”“实验原因”3个层面对现阶段高中生化学学习障碍成因进行初步分析,并从教学策略、评价策略、实验策略等方面提出相关教学建议.     

大学生化学实验学习障碍的调查报告

根据自行编制的学习障碍诊断工具,对大学生化学实验学习情况进行了调查,探查出“获取信息面狭窄”、“难以进行信息加工”、“实验信息储存求同不求异”、“难以迁移、类比实验方法”、“实验操作缺乏协调性与敏捷性”等实验学习障碍,这些障碍极大地影响着大学生实验能力和创新能力的形成。     

初中生化学符号学习能力的差异研究

化学符号知识是初中生化学学习启蒙阶段的关键内容,是学生进行一系列化学思维活动的基础。通过问卷调查、访谈等方法,对不同学业水平学生化学符号知识学习的差异及其原因进行了分析探讨。     

初三化学教学要重视对学生进行学习目的和辩证唯物主义观点的教育

初三化学是中学生学习化学的开端.??教师要引导学生爱好化学,学好化学,可以通过多种途径.现就对学生进行学习目的教育和辩证唯物主义观点教育,谈点看法. 一、明确教学目的,结合实际对学生进行学习目的教育. 为了使学生学习化学有个良好的开端,必须让他们明确学习化学的目的和重要性,这一点非常重要. 在化学的第一堂课——绪言上,就要使学生清楚地知道:世界是物质的,化学研究的对象就是物质.所以,化学研究的范围是非常广泛的,化学与各门科学、工农业生产、国防建设和     

初中化学概念形成与教学策略

化学基本概念的学习往往成为初中学生成绩的分化点,在教学中帮助学生克服这一学习障碍,体现新课程所强调的过程、方法、情感等的教学理念是亟待解决的课题,本文通过对概念结构以及概念形成的细化分析,探讨了概念教学中培养学生掌握与应用概念的能力以及降低概念理解难度的途径。     

高三学生化学选择学习能力现状的实证研究

培养受教育者具有选择意识和科学的选择能力是培养人的主体性的重要内容,是现代教育的特征。从选择学习的心理机制出发,探究选择学习能力的本质与构成要素,以高三学生的化学学习为基础,综合运用问卷调查法、问卷测试法以及访谈法分析高三学生化学选择学习能力的现状。结果表明:相当一部分学生自主选择意识薄弱;识别选择条件能力欠缺;不能根据自身情况做出科学合理的选择学习判断;在实施选择活动过程中,不能勇敢地面对和克服学习中遇到的困难和障碍、学生认知结构不够完善、思维品质较低、算法优化意识和能力严重缺失,不能保质保量地完成学习任务;缺乏反思意识,后续学习效率低下。     

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。     

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。     

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.     

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。