“普通化学”小组合作学习研究与实践

合作学习是以生生互动为主要途径促进学生学习的教学方式和学习策略.结合教学实践,针对目前“普通化学”教学现状不足,介绍了在普通化学教学中开展合作学习的具体措施,并阐述了合作学习的重要意义.     

充分利用《化学与生活》模块的活动性栏目转变学生学习方式的一些尝试

《普通高中化学课程标准(实验)》明确指出“转变学生的学习方式是课程改革的基本要求。教师要更新教学观念,在教学中引导学生进行自主学习、探究学习和合作学习,帮助学生形成终身学习的意识和能力。”针对《化学与生活》选修模块中“活动.探究”、“动手空间”、“角色扮演”、“学以致用”等活动性栏目功能和特点的不同,在教学中采取了不同的教学策略,促进了学生的自主学习、探究学习及合作学习。     

合作学习--一种有效学习的策略

合作学习是新课程大力倡导的主要学习方式之一,结合化学教学实际从精心设计讨论问题、把握合作学习时机、明确个人责任和转变教师角色等方面进行了论述,以促进学生有效地合作学习。     

高中化学合作学习有效性调研报告

课题研究以问卷形式,调查高中化学合作学习,就合作学习的开展形式和有效性所存在的问题,从个案角度进行分析.表明:合作学习提高了学生在课堂上交流与合作的意愿与能力,促进了师与生、生与生之间的交流,有助于学生的团结协作和课堂教学质量的提高;学生从单一的知识接受个体转变为效率优先、方法并重的开放式学习个体.推进合作学习,教师应从两个有利入手:一是有利于学生从无意识合作转化为有意识的合作;二是有利于知识与理论问题的解决.     

“合作学习”应用于化学教学的一次实验报告

“合作学习”教学一改传统教学中教师和学生的冲突关系,立足学生个性的全面和主动发展,通过学生间的合作—教师不直接参与学生的学习活动—自主学习。     

基于学生自主、合作学习过程的元素化合物课型教学实践——以“铁盐和亚铁盐的性质”为例

在“国培计划”高中化学观摩课“铁盐和亚铁盐的性质”的教学设计和教学实践中,通过向学生提供具有一定开放性和综合性的学习任务,学生在自主、合作学习过程中对元素化合物性质的学习内容产生深度思考,并对学习过程产生深度体验。教学结束后,通过问卷调查学生对自主、合作学习过程的自我评价,对元素化合物课型中促进学生自主、合作学习能力发展的教学理念和教学方法进行讨论。     

新课程中学生自我认知能力检测初探

新课程强调,教师是学生学习的合作者、引导者和参与者,教学过程是师生交往、共同发展的互动过程,强调了学生主体性,注重了实践和创新,以学生的发展为本.广大教师还注重了学生的合作学习,培养合作这一现代人的基本素质.心理学研究表明：同龄伙伴的影响大大超过成年人对他们的影响.中学生天性喜好伙伴间的交流,他们十分欢迎用讨论与合作的方式学习,共同感受探索的焦急,承受失败的失望,一起分享成功的快乐和喜悦,学生的自信心十足,自我感觉良好.而自我认知是个体对自己的认知过程和结果的意识,或者说是个体对自己学习状态的内部调节.它是一种极为重要的认知策略,是化学学习的重要组成部分.在化学学习中培养学生的自我认知能力,一方面有利于学生对学习实行自我监控,使其成为能自我导学的人,减轻了被动学习的重负.另一方面,教师亦可引导学生进行针对性复习,使学生从浩瀚的题海中解脱出来.尤为重要的是培养学生自我认知能力将有利于形成学生“自主”、“自立”的良好人格特征.     

化学新课程探究教学受阻原因例析

新课程在我省已经实施近3年,新课程教学的主导文化是探究学习、合作学习和自主学习.探究学习是否已经成为广大师生在课堂上的普遍行为?答案是肯定的:没有.是什么原因导致我们的课堂仍然"涛声依旧",探究教学进入中学课堂何以如此之难?下面我们通过一个教学实例进行简单分析.     

基于互动和合作学习的无机化学教学模式

在分析无机化学课堂教学现状和采纳学生建议的基础上提出了构建互动和合作学习的无机化学教学模式。着重介绍了"分组互动、读书报告会、尝试讲课和评判纠错"互动和合作学习的过程。教学实践表明,这种互动和合作学习正是学生需要和喜欢的无机化学教学模式。     

化学教学中培养学生合作学习能力的实验研究

学生合作学习能力高低直接影响到合作学习的质量和效率。如何在学科教学中培养学生的合作学习能力并对它进行发展性评价,是许多教育工作者所要面对和探讨的问题。本文通过实验对这一问题进行了研究,得出了高中化学教学中运用合作学习教学策略和合作学习能力发展性评价,能有效地提高学生的合作学习能力和学习成绩;使独生子女与非独生子女的合作学习能力水平缩小到无显著性差异;对不同性别高中生的合作学习能力发展水平没有显著性影响等结论。     

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。