讨论式教学在仪器分析课程中的实践探索

为提高课堂教学质量,发挥专业课程育人功能,基于仪器分析课程特点,尝试探索小组讨论式教学在仪器分析课程中的教学实践。从课程简介、教学设计、教学过程、教学评价等方面对讨论式教学进行总结,为化学专业课堂教学探索提供借鉴。     

培养学生绘制实验仪器装置图的能力

高考《考试说明》指出,绘制典型的实验仪器装置图(以下简称制图)的能力是实验能力的一个重要方面。结合本人多年教学实践,笔者就如何培养学生制图能力谈一点认识和做法。1　基本认识绘制规范、美观的实验仪器装置图是化学实验基本功之一。通过培养学生的制图能力,不仅能使学生这方面的能力得以提高,具备一项较好的化学实验基本功;而且,在教师的指导下,学生经过观察和绘图,还能激发学习兴趣,加深对仪器构造与用途的了解,巩固对装置组合原理与应用的认识,强化相关实验操作知识,促进观察能力和形象思维的发展,训练心眼手的配合,培养科学素质,提…     

高师“化学教学论”课堂教学改革与实践

"化学教学论"是高师院校化学教育专业中最能体现师范性,与基础教育化学教育教学联系最为紧密的一门专业必修课程,但没有得到师范生应有的重视。为此,内蒙古师范大学的"化学教学论"课程从教学内容、教学模式及教学评价3个方面进行了课堂教学改革,并取得了一定的成效,既促进了学生的学习积极性和课堂参与度,又训练并提高了学生的课堂教学技能。     

基于一流课程建设的分析化学实验教学改革与实践

分析化学是化学的四大基础课程之一,通常包含化学分析和仪器分析两门课程。我校自1983年建系以来即面向化学类专业开设了与理论课程向对应的分析化学(含仪器分析)实验课程。面向目前我校的化学和应用化学专业的学生,我们以精选教学内容、设计渐进式课程和采用多维度教学模式为主要改革方向,建设分析化学(含仪器分析)实验一流本科课程。     

基于不同专业背景的仪器分析教学改革初探

仪器分析课程是很多专业的基础课,在东北林业大学,除化学、化工和应用化学专业开设仪器分析课程之外,还有材料化学、轻化工程、林产化学、环境科学等专业也相继开设了仪器分析必修课或选修课。针对不同专业背景,选择不同教学内容及实验项目,以适应专业需求并结合专业的科研特色进行仪器分析探索性教学改革。     

在化学课堂教学中践行陶行知教育思想——“3S+L”教学模式的创建与实践

以陶行知教育思想和高中化学课程理念为理论支撑,创建"3S+L"教学模式。通过"从生活(S)走进化学"、"用实验(S)探究真相"、"用理论(L)提升认识"、"从化学走向社会(S)"等4个教学环节,在化学课堂教学中践行陶行知"生活即教育"、"社会即学校"、"教学做合一"的教育思想。用"二氧化硫"的课堂教学为案例诠释"3S+L"教学模式。     

线上线下混合式"仪器分析实验" 课程实践与思考——以气相色谱实验为例

在新型冠状病毒肺炎疫情期间,由于学生无法返校,中国科学技术大学化学实验教学中心仪器分析实验课程组利用自主开发的大型仪器虚拟仿真软件,应用"智慧课堂"教学模式,进行了线上教学与实验;在学生返校后,又开展了真实实验。本文介绍了该次实验课程开展过程中的线上线下教学活动及教学效果总结,提出了对于线上线下混合式一流课程建设的一些思考。     

案例教学模式在工科化学教学中的应用

结合"工科化学"课程的特点和存在的问题,从体现专业特色、与生活实践紧密结合、紧跟学科前沿和与探索性实验结合等4个方面探索在理论教学中引入应用案例教学模式,激发学生学习积极性和主动性,提升"工科化学"的课堂教学效果。     

新课程背景下化学课堂教学设计的实践与思考

化学课程标准下的化学课堂教学怎样才能体现出课程改革的新理念?从课堂教学的理念、课堂教学的宗旨、课堂教学的资源、课堂教学的过程等角度,探讨了新课程背景下化学课堂教学的设计与实施的准则与案例。     

理工科院校仪器分析课程教学改革探索

仪器分析是理工科院校化学及相关学科本科生的专业基础课程。本文针对仪器分析课程具有的前沿性、发展性、实践性和应用性等特点及在教学中存在的问题,提出了仪器分析课程教学改革的思路。     

ICP-AES测定铀污染土壤植物中铀的研究

采用电感耦合等离子体发射光谱(ICP-AES)对铀污染土壤植物中铀的测定方法进行了研究.在λU385.958 nm处,选择了仪器的最佳工作条件,考察了酸度和常见共存元素对测定的干扰情况,并且对比了干灰化消解和湿式消解对测定的影响.研究发现2%硝酸溶液为最佳介质,干扰离子对测定没有显著影响,干灰化消解比湿式消解得彻底.在选定条件下,方法检出限为0.18 mg·L-1,测定下限为0.61 mg·L-1,5.0000 mg·L-1的铀标准溶液的相对标准偏差RSD(n=10)为0.81%,方法回收率为96.2%～106.2%.该方法操作简单,快速.结果表明,用ICP-AES测定铀污染土壤植物样品中的铀是可行的.     

测定血清中Na 含量不确定度的评定

对血清中Na离子含量的测量不确定度进行评定。不确定度的来源主要包括Na离子标准工作液的配制过程、血清样品的定容消化制备、标准曲线拟合、钠离子各分量不确定度的合成等引入的不确定度计算出各分量的不确定度,通过合成得到测量结果的合成不确定度、扩展不确定度及测试结果的报告形式。     

Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat

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 (As_i). In order to document the methylation process in humans, the kinetics of As_i, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of As_i. 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 As_i 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 As_i 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.     

Kinetics of dehydration in chelates of quinones involved in photosystem-II

The solid-state deaquation of thetrans- andcis-oximates of lawsone (I) and phthiocol (II) with cobalt(II) was investigated by means of non-isothermal thermogravimetry. The modes of deaquation during the thermolyses of hydrated oximates of (I) and (II) with compositions CoL₂·2H₂O were compared. The weight lossvs. temperature data were treated by using the Coats and Redfern relations. The kinetic data support a rearrangement-type mechanism for the deaquation of the oximate of phthiocol. TheE _a values for both the ligands and water molecules were found to be 23 kJ/mol.

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Zusammenfassung Mittels nichtisothermer Thermogravimetrie wurde die Dehydratation der trans- und cis-Kobalt(II)-oximate von Lawson (I) und Phthiokol (II) untersucht. Die Arten der Dehydratation während der Thermolyse der hydratierten Oximate von (I) und (II) mit der Zusammensetzung CoL₂·2H₂O wurden verglichen. Bei der Auswertung der Massenverlust-Temperatur-Daten wurden Coats-Redfern Beziehungen angewendet. Die kinetischen Daten bekräftigen einen Umlagerungsmechanismus für die Dehydratation des Oximates von Phthiokol. DieE _a Werte betragen sowohl für die Liganden als auch für Wasser etwa 23 kJ/mol.

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- - (I) (II) . I II CoL₂ · 2₂ . -. . _a , 23 · ^–1

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Production of radicals in the ozonolysis of propene in air

Radical production in the ozonolysis of propene in air was monitored directly by a peroxy radical chemical amplification (PERCA) instrument at room temperature (298±2 K) and atmospheric pressure (1×105 Pa). The ozonolysis reactions were conducted in a flow tube under pseudo-first-order conditions for ozone. The decay in ozone was calculated based on reaction time tr and effective rate constant keff (keff = k1[C3H6]0)) for the ozone-propene reaction. The total radical yields relative to consumed ozone were d...     

Use of matrix-modifiers in atomic-absorption determination of chromium in argillites

The direct atomic-absorption determination of chromium in argillites, without preliminary concentration and separation, has been studied. A map of selective flame zones for determining Cr in argillites has been designed. An express method for determining Cr in Estonian argillites has been suggested.     

Effect of vibration in processes of structure formation in polymers

It was shown that the strength characteristics of the samples produced from thermoplastics (low density polyethylene, polyamide 6, Armamid, and polyethylene terephthalate) increase as a result of short vibration treating with a frequency close to that of natural vibrations of the structural elements.