共查询到20条相似文献，搜索用时 171 毫秒
1.
利用热分析法研究苯甲酸在氮气流中以不同的升温速率(β=3、6、10、20、30℃.min-1)时的热分解过程与热分解动力学.确定了苯甲酸的平衡起始热分解温度T0=392 K;由Kissinger与Coats-Redfern两种经验公式求得该热分解反应的表观活化能E=70.4 kJ.mol-1.用32种常用的热分解机理函数对该分解过程进行计算,推算出一系列活化能,与经验公式得出的表观活化能比较,确定苯甲酸的热分解机理函数为:g(α)=α. 相似文献
2.
对-叔丁基杯[6]热力学及热分析动力学研究 总被引：1，自引：0，他引：1
用热重TG和DSC对对-叔丁基杯[6]的热分解过程进行了研究,用"DSC-TG"结合法推断出了对-叔丁基杯[6]热分解的可能过程,求出了其热分解反应动力学方程及热分析动力学参数;其热分解的过程为四号机理函数,为球型三维扩散过程.其动力学方程为:f(a)=3/2[(1-a)1/3-1],活化能为168.7KJ.mol-1,指前因子为8.54×1037S-1. 相似文献
3.
利用数学工具软件Mathcad2001,对4Na2SO4·2H2O2·NaCl加合物的热分解动力学方程模型中的参数进行优化,得到了其热分解动力学方程式,优化的结果能准确地模拟4Na2SO4·2H2O2·NaCl的实际分解过程.Mathcad的使用大大减少了计算工作量.对于其它物质的热分解过程、非均相及均相体系反应的动力学方程式参数都可用Mathcad2001工具软件进行优化. 相似文献
4.
用热重TG和DSC对—叔丁基杯[6]的热分解过程进行了研究,用“DSC—TG”结合法推断出了对—叔丁基杯[6]热分解的可能过程,求出了其热分解反应动力学方程及热分析动力学参数;其最概然机理函数为21号,为一级反应过程。表观活化能为101.79 KJ.mol-1,指前因子的对数为51.64 S-1。 相似文献
5.
熊辉 《黄冈师范学院学报》1993,(2)
本文通过TG—DTG—DTA实验方法,对氯酸钾催化热分解反应动力学及其反应过程进行了研究,并与氯酸钾的非催化热分解反应比较,结果是:分解反应都是连续一次进行完毕;催化剂二氧化锰降低了反应的活化能,使反应起始温度下降,反应速度常数提高了三个数量级。对于可能的反应机理亦作了初步推断。 相似文献
6.
用TG-DTG(热重-微分热重)联用技术研究了氨茶碱片剂在氮气气氛中的热分解行为。首先运用普适法Kissinger和Ozawa法计算了氨茶碱片剂的表观活化能E和指前因子lnA,然后运用一般积分法Coats-Redfern法和Satava-Sestak法推测了主分解阶段的最佳热分解机理,推测出热分解机理为相边界反应,求出了热分解反应的表观活化能和指前因子。几种方法求得的表观活化能和指前因子的平均值分别为113.933KJ/mol,lnA为22.101(1/min).用malek法对所得结果进行了验证,进一步证明所得动力学参数和机理函数的正确性。 相似文献
7.
目的:研究了氨基甲酸甲酯类的甲苯咪唑和丙硫咪唑热分解特征.方法:应用TG、DTA、%TG方法进行热分析及动力学研究.结果:对甲苯咪唑和丙硫咪唑在空气介质中的热分解特征进行了定性、定量表征.结论:热分析方法可作为氨基甲酸甲酯类驱虫药的一种快速、简便的检验方法. 相似文献
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9.
采用TG-DTA分析研究了一水邻苯二甲酸钙热分解过程,对其中的脱水过程进行了动力学计算. 由Friedman和Ozawa-Flynn-Friedman法得到脱水过程的活化能和指前因子,用Archar方法计算拟合了几种机理函数,确定了脱水过程的优化动力学参数及最佳机理模型. 脱水过程的活化能Ea为141.1576 kJ/mol,反应的机理模型为Bna,即f(α) =(1-α)n*αn. 相似文献
10.
采用热重法(TG)和差示扫描量热法(DSC)测定了拉米夫定(LMVD)在氮气氛中的热分解过程,结果表明LMVD的热分解过程是一个二阶段过程,运用量子化学GAMESS软件计算了LMVD分子的键级,测定了LMVD及其在热分解过程中不同阶段残留物的红外光谱,推测了LMVD的热分解机理.根据不同升温速率下的热重曲线计算得到LMVD第一阶段热分解反应动力学参数,表现活化能Eα=126.5 kJ·mol-1,指前因子A=2.88×1011min-1.推算了不同使用温度下LMVD的预期寿命. 相似文献
11.
从认知科学及其脑科学的前沿，探讨了大脑神经网络巨系统的功能特点。知觉及思维的产生正是大脑复杂的神经网络巨系统中各子系统的协同综合作用的结果。基于这一机制和特点，初步提出了大脑协同学的一些基本原理和方法。由协同学的基本方程，我们定量导出Lorenz方程和Lorenz模型。其中的两翼对应于大脑的两个半球，两翼之间的跳来跳去形象地描述思维。由此说明生命在于混沌中的协同。大脑协同学具有三个层次：大脑的结构、活动和思维，及进一步的心身协同学。在此，我们尝试以一种新的理论模型对认知科学及脑科学进行某些探讨。 相似文献
12.
Chemical kinetics is an extremely important concept for introductory chemistry courses. The literature suggests that instruction in chemical kinetics is often teacher‐dominated at both the secondary school and tertiary levels, and this is the case in Thailand – the educational context for this inquiry. The work reported here seeks to shift students from passive learning to more active, student‐centred learning and involved some 413 first year undergraduate science students in Thailand. Drawing on inquiry‐based learning, the participants were asked to design an experiment investigating the reaction of acids and bases. The research findings suggest that participants were able to explain the changes of the rate of a chemical reaction, and developed good conceptual understanding of chemical kinetics both qualitatively and quantitatively. It also showed this more active teaching approach, which is radically different from normal teaching in Thailand, was an enjoyable experience for the students. 相似文献
13.
Traditionally the kinetics of a chemical reaction has been studied as a set of coupled ordinary differential equations. The law of mass action, a tried and tested principle for reactions involving macroscopic quantities of reactants, gives rise to deterministic equations in which the variables are species concentrations. In recent years, though, as smaller and smaller systems – such as an individual biological cell, say – can be studied quantitatively, the importance of molecular discreteness in chemical reactions has increasingly been realized. This is particularly true when the system is far from the ‘thermodynamic limit’ when the numbers of all reacting molecular species involved are several orders of magnitude smaller than Avogadro’s number. In such situations, each reaction has to be treated as a probabilistic ‘event’ that occurs by chance when the appropriate reactants collide. Explicitly accounting for such processes has led to the development of sophisticated statistical methods for simulation of chemical reactions, particularly those occurring at the cellular and sub-cellular level. In this article, we describe this approach, the so-called stochastic simulation algorithm, and discuss applications to study the dynamics of model regulatory networks. 相似文献
14.
从６个方面论述了动力学中有关化学反应速率方程、反应级数、反应分子数、反应机理、化学计量系数等之间的联系与区别。 相似文献
15.
"协同学"理论在成人教育教学中的应用 总被引：1，自引：0，他引：1
吕毅坚 《广东广播电视大学学报》2007,16(4):12-14
协同学理论是著名物理学家哈肯在70年代初研究激光理论时提出的.协同学是研究协同系统在外参量的驱动下和在子系统之间的相互作用下,以自组织的方式在宏观尺度上形成空间、时间或功能有序结构的条件、特点及其演化规律.本文通过对成人教学过程的分析和现代教学要求对比协同学理论,提出了运用协同原理进行教学,帮助学生形成学习的自组织,使其终身受用的一种教学理念及运用方法. 相似文献
16.
将协同理论应用于区域旅游发展存在合理的机理内核,旅游产业的协同发展是区域旅游发展的必然选择。协同发展是济宁市旅游产业发展的迫切要求,因此,分析济宁市旅游产业实现协同发展的现实基础,并据此提出实现协同发展的对策建议,对济宁市旅游产业的跨越式发展具有重要意义。 相似文献
17.
贺磊 《西安文理学院学报》2014,(4):95-99
以黄土为原料并从中提取粘土矿物,研究粘土矿物对氯吡硫磷的吸附行为,并从吸附等温线,动力学和热力学角度对其吸附机理进行探讨.吸附等温线模型研究表明,粘土矿物对氯吡硫磷的吸附属于Langmuir和Freundlich的复合型吸附;吸附动力学模型研究表明,该过程符合拟二级动力学方程;吸附热力学参数研究表明,该过程是一个自发的吸热反应,且主要作用为氢键吸附.研究结果有助于进一步探究土壤中残留农药的自净机理. 相似文献
18.
Elementarc Reaction(基元反应)是化学动力学中一种特殊类型的反应形式,其在化学动力学上具有三个显著的特征,笔者在文中对这三个动力学特征进行了揭示和分析。 相似文献
19.
A detailed mathematical model of a direct internal reforming solid oxide fuel cell (DIR-SOFC) incorporating with simulation of chemical and physical processes in the fuel cell is presented. The model is developed based on the reforming and electrochemical reaction mechanisms, mass and energy conservation, and heat transfer. A computational fluid dynamics (CFD) method is used for solving the complicated multiple partial differential equations (PDEs) to obtain the numerical approximations.The resulting distributions of chemical species concentrations, temperature and current density in a cross-flow DIR-SOFC are given and analyzed in detail. Further, the influence between distributions of chemical species concentrations, temperature and current density during the simulation is illustrated and discussed. The heat and mass transfer, and the kinetics of reforming and electrochemical reactions have significant effects on the parameter distributions within the cell. The results show the particularchar acteristics of the DIR-SOFC among fuel cells, and can aid in stack design and control. 相似文献
20.
The present paper discusses the conceptual demands of an apparently straightforward task set to secondary‐level students—completing chemical word equations with a single omitted term. Chemical equations are of considerable importance in chemistry, and school students are expected to learn to be able to write and interpret them. However, it is recognised that many students find them challenging. The present paper explores students’ accounts of their attempts to identify the missing terms, to illuminate why working with chemical word equations is so challenging from the learner’s perspective. Three hundred secondary‐age students responded to a five‐item exercise based on chemicals and types of reactions commonly met at school level. For each item they were asked to identify the missing term in a word equation, and to explain their answers. This provided a database containing more than 1,000 student accounts of their rationales. Analysis of the data led to the identification of seven main classes of strategy used to answer the questions. Most approaches required the coordination of chemical knowledge at several different levels for a successful outcome; and there was much evidence both for correct answers based on flawed chemical thinking, and appropriate chemical thinking being insufficient to lead to the correct answer. It is suggested that the model reported here should be tested by more in‐depth methods, but could help chemistry teachers appreciate learners’ difficulties and offer them explicit support in selection and application of strategies when working with chemical equations. 相似文献