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梳理了部分国内综合性院校本科化学类实验的课程设置及所用化学实验教材,同时简单介绍了科学仪器的分类。针对各类化学实验教材中分析仪器部分的内容重复、更新不及时、深度不够等问题,提出了解决方案,希望能对今后化学实验教材的编写提供不同的视角和有益的借鉴。 相似文献
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以大学化学系新生为实验对象,以分析天平为实验材料,对化学实验操作技能的遗忘进程进行了实验研究,讨论了化学实验操作技能遗忘曲线理论,对实验结果进行了探讨,提出了改进化学实验教学,提高学习质量的看法和建议,从而补充了动作操作遗忘进程在化学实验操作技能中的遗忘规律。 相似文献
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举例分析了中学化学"纸笔实验"试题中常见的4种错误是实验内容不真实、实验结论不可靠、实验方法不现实、涉及物质不实际,并阐述了由此带来的问题。 相似文献
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以“二氧化碳的性质和用途”为教学案例,设计了家庭实验和分组实验等实验探究活动,改进了传统的演示实验与板书,并对上述内容进行了整合研究,形成了基于实验探究的整合教学模式。 相似文献
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物理化学实验改革探讨 总被引:11,自引:0,他引:11
计算机技术的发展和先进仪器的应用给物理化学实验增添了新的活力和更大的发展空间。为了顺应时代的要求,我们将计算机技术应用于物理化学实验,不仅提高了实验的技术与手段,提高了实验结果的准确度和精确度,而且增加了实验的内容和信息含量,提高了学生的实验兴趣。根据“新世纪高等教育教学改革工程”的设计方案,化学专业的化学基础实验课内容分3个层次:基本实验,综合实验和研究型实验。在保留和完善基本的经典实验的基础上,增加了综合实验和设计实验,这类实验涉及的知识面宽,要求学生综合运用所学的知识思考并解决实验中的问题。现将物理化… 相似文献
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提高高分子化学实验效果的尝试 总被引:4,自引:0,他引:4
以丙烯酰胺的水溶液聚合为例,探讨如何提高高分子化学实验的作用:一是将验证性实验扩展为研究性实验,即将同一实验内容改变实验条件分给不同组进行,而后汇总讨论;二是引导学生认真观察实验现象,广泛地与生产实际相联系,和后续课程进行衔接,丰富了实验内涵.研究性实验和丰富实验内涵极大地激发了学生学习兴趣与潜能,从而提高了实验效果. 相似文献
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微型实验的最大特点是突出了实验设计的简约性原则,即采用简单的实验装置,用较少的实验步骤和实验药品,在较短的时间内取得较明显的实验结果.这一优点使其容易推广为学生分组探究实验,也更有利于发挥学生探究学习的主动性. 相似文献
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对农林大学“有机化学实验”课程教学的模式进行了探索.采用了第一课堂教学平台加第二课堂教学平台的教学模式.充分有效利用第一课堂平台的同时也积极拓展第二课堂的教学功能,既解决学时不足,又达到了教学目的.本课程教学模式的改革与实践给学生提供了个性发展的空间,满足了不同层次不同专业学生的需求,使学生建立了初步的科学研究的基本方法和思想.进一步激发了学生自主的、积极的思考意识,教学实践表明,新的有机化学实验体系的形成,综合性、设计性和开放性实验的开设,使有机化学实验课程更适合高素质人才培养的需要. 相似文献
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The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (Asi). In order to document the methylation process in humans, the kinetics of Asi, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of Asi. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As2O3) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of Asi metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of Asi uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems. 相似文献
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Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain. 相似文献
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A. P. Grimanis N. Kalogeropoulos V. Kilikoglou M. Vassilaki-Grimani 《Journal of Radioanalytical and Nuclear Chemistry》1997,219(2):177-185
Neutron activation analysis (NAA) is a very sensitive and accurate multielement analytical method that is widely applied to the investigation of environmental and archaeological problems. The first part of this paper is a review of pollution studies of toxic trace elements in sediments, seawater and marine organisms of Saronikos Gulf, Greece by NAA. The second part of this paper is a review of provenance studies based on minor and trace element research in ancient ceramics, obsidian, flint, limestone, marble and lead by Instrumental NAA, performed at the NCSR Demokritos. 相似文献
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In situ generation of reactive species within confined geometries, such as nanopores or nanochannels is of significant interest in overcoming mass transport limitations in chemical reactivity. Solvent electrolysis is a simple process that can readily be coupled to nanochannels for the electrochemical generation of reactive species, such as H(2). Here the production of hydrogen-rich liquid volumes within nanofluidic structures, without bubble nucleation or nanochannel occlusion, is explored both experimentally and by modeling. Devices comprised of multiple horizontal nanochannels intersecting planar working and quasi-reference electrodes were constructed and used to study the effects of confinement and reduced working volume on the electrochemical reduction of H(2)O to H(2) and OH(-). H(2) production in the nanochannel-embedded electrode reactor output was monitored by fluorescence emission of fluorescein, which exhibits a pH-dependent emission intensity. Initially, the fluorescein solution was buffered to pH 6.0 prior to stepping the potential cathodic of E(0)' for the generation of OH(-) and H(2). Because the electrochemical products are obtained in a 2:1 stoichiometry, local measurements of pH during and after the cathodic potential steps can be converted into H(2) production rates. Independent experimental estimates of the local H(2) concentration were then obtained from the spatiotemporal fluorescence behavior and current measurements, and these were compared with finite element simulations accounting for electrolysis and subsequent convection and diffusion within the confined geometry. Local dissolved H(2) concentrations were correlated to partial pressures through Henry's Law and values as large as 8.3 atm were obtained at the most negative potential steps. The downstream availability of electrolytically produced H(2) in nanochannels is evaluated in terms of its possible use as a downstream reducing reagent. The results obtained here indicate that H(2) can easily reach saturation concentrations at modest overpotentials. 相似文献
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Reactions in droplets in microfluidic channels 总被引:5,自引:0,他引:5
Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights. 相似文献
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