比较两种分析化学实验方法的实验

分析化学实验课是分析化学课程的重要组成部分 ,它与理论课教学密切配合 ,教给学生分析化学的基本理论、基本知识和基本实验技能。现有的分析化学实验在测定方法、实验原理等方面与理论课中各章对应的原理有很好的配合。但是如何将数据处理一章的有些内容与实验结合起来 ,加深学生对这部分内容的理解是实验教材中应该加以考虑的。但至今实验内容中基本是以测定样品中组分含量为目的的 ,能涉及到数据处理的很少。特别是数据的检验部分 ,现在的实验内容都无法用上。为此我们认为适当安排一些能进行数据检验的实验很有必要。这样通过分析实验学…     

一种酸碱滴定的综合实验及计算程序

在分析化学实验教学中,安排pH滴定的实验,有助于学生加深对酸碱滴定理论的理解。我们曾在分析化学实验教学中安排了pH滴定和缓冲容量的实验,但是数据处理较繁琐。为此,我们在原有实验的基础上设计了一种酸碱滴定的综合实验和计算程序。通过本实验希望达到以下目的:(1)熟悉pH计的使用方法;(2)了解滴定的基本原理,并掌握用一级差商和二级差商法确定终点的方法;(3)对缓冲容量的有关理论进行验证;(4)运用计算机处理实验结果等。     

大学化学综合实验教学实践——紫草药材提取实验

常见中药材紫草的主要活性成分为羟基萘醌类化合物，其具有多种药理作用。将紫草中羟基萘醌类化合物的提取引入有机化学基础实验课程，对于可变参数——提取时间和加醇倍量进行研究，学生自行设计并实施实验。该实验综合使用有机化学及分析化学实验基础操作的同时，提升学生学习兴趣，提高学生实验设计、数据处理及分析的能力。     

以分析全过程为导向的分析化学综合实验：石墨炉原子吸收光谱法测定大米中的镉含量

目前高校开展的分析化学实验内容较单一,忽视了培养学生对分析全过程的质量保证和质量控制的能力,缺乏对学生探究能力和综合素质的培养。因此,我们设计了一项包含样品的制备、方法的适用性验证、样品前处理、上机分析和数据处理以及实验过程中如何做好质量保证和质量控制等步骤的分析化学综合实验。该实验以大米为试样,指导学生利用石墨炉原子吸收光谱仪器、基于外标法定量、综合运用多种质量保证和质量控制措施对大米中的镉含量进行准确测定。本实验涉及到分析的全过程,综合性较强,既有利于学生将所学的理论知识应用于实践分析中,也有利于提高学生分析问题和解决问题的能力,能更好地培养学生的探究性思维。本实验易于操作,实验过程安全性较高,且能在8学时内完成,适合高校中分析化学教研组以小组制、项目化的形式向本科二、三年级的学生开设。     

分析化学综合实验中的软件实验教学设计——以Excel为例

以Excel为例, 从实验设计原则、实验内容、教学手段等方面系统介绍了分析化学综合实验中软件实验的教学设计, 对提高学生实验数据分析能力及处理效率具有重要作用, 是分析化学实验教学的有益探索。     

普通化学实验辅助教学系统简介

为提高实验教学质量,减轻教师的工作负担,提高工作效率,增强和激发学生的学习兴趣,我们将PC-1500袖珍计算机逐步应用于实验教学,当堂检查学生的实验结果,进行数据处理及作图.又将各个实验程序结合、联系在一起,组成了该系统.此系统由两部分组成:第一部分是学生成绩管理,包括建立学生档案、成绩存贮、档案检索、修改、缺课名单、全优名单,打印成绩单、排名次等功能.第二部分是实验数据处理     

分析化学实验的绿色化及废液处理

分析化学实验过程中使用的试剂用量大,产生的废液较多,会对环境造成较大污染,影响教师和学生的身体健康。因此,分析化学实验的绿色化及废液的绿色化处理具有重要意义。以湖南师范大学化学化工国家级实验教学示范中心分析化学基础实验为例,采取微型化等方式对分析实验项目进行了绿色化改革,并以资源再利用等方式对分析实验废液进行处理。     

分析化学综合实验：分光光度法测定工业油品加氢脱硫催化剂中镍和钼的含量

针对目前高校开展的分析化学实验内容单一、项目陈旧等问题,将创新综合性实验教学项目引入到课堂教学中,能够增强学生独立思考、主动探索和解决问题的能力。因此,我们设计了包括样品制备、分析测试、数据处理及结果对比等步骤的实验教学方案。该实验以分光光度法测定Ni、Mo金属含量为目的,通过对工业油品加氢脱硫催化剂(Ni-Mo/γ-Al₂O₃)进行制备及金属含量测定,使学生既能了解负载型催化剂制备的常规实验方法,又能掌握分光光度法定量分析技术。     

基于问题导向学习法的分析化学实验与理论知识融合的教学改革——以“水硬度的测定”为例

分析化学实验是一门兼具理论性、实践性和应用性的课程,主要训练学生规范操作并培养学生运用分析化学理论知识解决实际问题的能力。目前普遍存在着分析化学实验课程教学与理论教学严重脱节的问题,学生习惯“照方抓药”。本文将问题导向学习法应用于分析化学实验教学,通过改进教学模式、完善课程内容和优化考核方式开展教学改革,促进实验与理论教学的有效融合,充分调动学生的学习自主性,培养学生观察、思考、分析和解决问题的能力,有效提高实验课的教学效果。     

生物质吸附剂的制备表征及其对水中Cu~(2+)吸附性能的研究

介绍一个集物理化学、分析化学于一体的综合性实验——生物质吸附剂对水体中Cu~(2+)吸附性能研究。首先制备出生物质吸附剂,并运用红外光谱仪分析其结构;考察了pH、时间、温度等条件对吸附剂吸附Cu~(2+)的影响,研究其吸附机理。该实验涉及物理化学的表面吸附原理和分析化学中分析方法的运用、大型仪器的使用,以及数据处理方法,既锻炼了学生的动手操作能力,又提高了学生对实验数据的处理分析能力。     

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.     

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。     

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.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。