氧化镁用于制备氢氧化铁胶体的实验设计

Fe（OH）3胶体的制备是中学重要的课堂演示实验,由于实验过程需要加热而耗时较长。从理论与实验的角度证实了使用MgO可促进Fe3+水解形成Fe（OH）3胶体。该方法在常温下即可进行,无需加热,实验成功率高及实验现象明显,符合绿色化学理念,非常适合课堂演示实验与学生自主实验。     

采用自制教具演示氯水光解实验

鉴于传统的氯水光解实验装置存在诸多弊端,且在短时间内难以观察到预期的实验现象,结合教学实践采用生活中常见废弃物自制一套演示氯水光解实验的教具,能在课堂上成功地演示,光照5 min便可观察到较为明显的实验现象,取得了较好的课堂演示效果。     

压强对化学平衡影响的实验改进

化学是以实验为基础的自 然科学, 而课堂演示实验的好坏直接影响着化学教学的效果和质量。     

压强对化学平衡影响的实验改进

化学是以实验为基础的自然科学,而课堂演示实验的好坏直接影响着化学教学的效果和质量.     

课堂演示型CAI的探讨

化学教学中,课堂演示型 CAI和交互型 CAI应有所不同。课堂演示型 CAI,要求教师把CAI定位在辅助地位,根据课堂教学的需要,适当选用辅助内容,而不是满堂都是屏幕、文字、声像并以此代替教师的教学 ;还要求教师精心设计板书,认真做好实验,而不是用“干实验”代替真实验 ;注重把节省出来的时间用在挖掘教材内涵、发展学生智能上,而不能仅仅用在加快教学进度上。     

压强对化学平衡影响的实验改进

化学是以实验为基础的自然科学,而课堂演示实验的好坏直接影响着化学教学的效果和质量.……     

聚苯胺的电化学合成实验

本文将新型有机固体导电材料聚苯胺的电化学合成引入大学高分子化学实验。合成方法简便易行。把高分子化学的新进展引入到高年级教学，有助于扩展学生的知识面。聚苯胺在外加电场变化时会发生颜色变化，使整个实验过程生动有趣，也可以用于课堂演示教学。     

化学演示实验的几点做法

化学是一门实验科学。而演示实验是化学教学最有效的方法之一。本文就化学演示实验的做法谈些浅见。一、演示实验的目的和要求一定要明确,教者必须做到心中有数,并交待给学生,演示前要做到:1.向学生说明演示的题目;2.向学生简要介绍实验装置;3.指出要求学生注意观察的部分;4.强调注意思考的问题.     

谈化学教学过程中生成性教学资源及利用

课堂生成性教学资源是教学活动前不能预设的、在教学过程中动态生成的有利于教学目标实现的各种因素。化学生成性教学资源产生于动态的化学教学过程;学生是化学教学资源的重要构成者和动态生成者;教师是化学生成性教学资源的开发者和课堂教学资源的重组者。化学教学过程中教师应对生成性教学资源加以识别、开发和利用。     

关于乙醛还原Cu(OH)_2实验的研究

乙醛还原Cu（OH）2是高中化学的一个重要实验，显示的是乙醛的还原性。反应按下式进行。2Cu（OH）2＋CH3CHO→Cu2O＋CH3COOH＋2H2O演示实验最重要的是现象准确，观察到的现象和预想的现象应严格一致，而且清晰、鲜明。根据反应式，该实验观察到的现象应该是有红色（也称砖红色）Cu2O沉淀生成。如果发生的就是这一个反应，现象应该是很清晰的。可是，在做此实验时往往看不到有红色沉淀生成，看到的却是一种黄褐色或红褐色浑浊，它和Cu2O的外观性质相差甚远。这种情况说明乙醇还原Cu（OH）2的反应不是一个简单的单一反应，而是有…     

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。