理科教师科学本质观发展策略的探索

帮助学生发展适当的科学本质观（VNOS）是科学教育的重要目标之一,而教师具有理想的科学本质观是实现这一目标的必要条件。有调查显示,现今理科教师的科学本质观基本处于较为朴素的水平,有待提高。鉴于此,本文在综合分析国内外相关研究的基础上,提出了一套符合中学理科教师实际情况的科学本质观发展策略。     

教科书中的元素周期律:科学本质的视角

教科书是影响学生理解科学本质的诸多因素中最重要的因素之一.知识呈现的逻辑线索、科学史内容的呈现以及语言的运用明确地表述或潜隐地渗透了特定的科学本质观.通过对不同类型高中化学教材中元素周期律呈现的比较分析,发现新版教科书更为重视学生对科学本质的理解,但由于传统沿袭、相关研究薄弱等原因,仍然没有很大突破.     

运用科学史培养初中生的科学本质观

通过科学教学使学生获得对科学本质的理解,建立起一定的科学本质观已越来越受到理科教育者的关注。科学本质的复杂性、丰富性决定了个人或社会对科学本质的理解与认识存在层次性和结构性。科学史教育是培养学生科学本质观的一个重要途径,如何在化学教学中运用化学史增强学生对科学本质的理解是摆在化学教育者面前的一个重要课题。从对科学本质和科学本质观的理解入手,初步确定了初中生应具有的科学本质观。通过一个具体化学教学案例的设计,介绍一种融合科学史培养学生科学本质观的化学教学模式。     

理科教师科学本质教学行为自我监控案例

培养学生适当理解科学本质观是科学教育的目标之一.本文以案例方式说明理科教师如何对于科学本质教学行为进行自我监控.     

认识论指导下的化学教学策略

什么可以被算作知识?知识是怎样发展的?知识受到哪些限制?谁拥有知识?知识的价值是什么?拥有或没有知识意味着什么?本文提出了认识论指导下的教学语言的选择、科学理论与模型教学策略、科学探究教学策略、全球化问题教学策略、科学知识的本质教学策略等,并进行了一学年的课堂教学实践,结果证明认识论指导下的科学教学有利于学生学习方式的改变,有利于培养学生的科学本质观、批判性与创造性。     

利用显性方法发展学生科学本质观的实践研究

理解科学本质的基本内涵是科学素养的核心,也是科学教育的重要目标。以106名初三学生为样本,设置对照组,研究在化学教学中用显性方法对发展学生的科学本质观的影响。     

中美高中化学教材中科学本质内容水平的比较及启示

理解科学本质是科学素养的核心成分,科学教材是影响学生和教师对科学本质理解的主要因素之一。通过对我国现行3套高中化学必修教材及美国主流化学教材《化学概念与应用》科学本质内容水平的比较,发现中美化学教材的科学本质内容水平都较低。建议教材编写以显性方式准确呈现科学本质内容,科学探究活动、化学史的编排需符合科学本质内涵,恰当设计反思性活动栏目,重构教科书文本话语。     

以微粒观促进学生对化学知识的深入理解——以“弱电解质的电离”教学为例

"微粒观"是化学学科的基本观念之一,具有微粒观能促进学生对化学知识深入系统地理解。在中学化学教学中,微粒观是从不同阶段、不同维度、不同水平进行建构的。"弱电解质的电离"教学设计基于学生"微粒观"的建构,以促进学生对"弱电解质的电离"的深层理解。分析了学生对"微粒观"的理解和认识基础,设计了"弱电解质的电离"的关键教学活动。     

“显性”科学本质教学与论证结合对学生科学本质观影响的研究综述*

科学教育文献建议运用“显性”教学提高学生对科学本质的理解,但其有效性仍有待加强。近年来,论证领域的新兴研究表明,学生参与论证对提高他们的科学本质观具有积极的促进作用。为了更好地提高学生的科学本质观,在梳理国际科学本质教育文献的基础上,探讨了“显性”科学本质教学与论证相结合的教学方法的研究脉络、研究方法及影响教学效果的因素。以期为教师进行有效的科学本质教学提供参考和建议,并对未来有关科学本质的有效教学的研究提供基础。     

论化学学习中想象思维的培养价值

想象是化学思维的基本形式,也是化学学习的基本方式。想象对于学生化学学习的价值主要在于帮助学生学习和理解化学的核心内容,形成“宏微符”3水平相结合的思维方式,进一步理解科学本质。     

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。     

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.     

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.     

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.     

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。