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1.
配位氢化物材料储氢是近年来学术界研究的热点.对目前正在研究的三类主要配位氢化物的热力学性质,动力学性质,含氢量,吸放氢过程,以及各种材料的优缺点都作了阐述和比较.  相似文献   

2.
根据量子化学,探讨了氢化物HnA(n=1,2,3,4)的热力学性质与量子化学的Xa价轨道能,有效键电荷QA-H的相关关系,从而提出了一个定量研究氢化物一些热力学性质与其结构之间关系的新模型,并用它计算了17种氢化物的5种热力学性质,计算值同实验值吻合。  相似文献   

3.
金属氢化物包括离子型金属氢化物和过渡金属合金氢化物(储氢合金).离子型金属氢化物是指含有负氢离子(H^-)并显有类盐性质的金属二元化合物,包括碱金属、碱土金属及镧系金属氢化物.笔者也把一些络合金属氢化物(如LiAlH4NaBH4等)包括进来,因为它们的反应活性类似于碱金属氢化物.碱金属和碱土金属中的钙、锶、钡能跟氢气在高温下反应,生成离子型氢化物,如NaH、CsH2等,其中的氢以H^-离子形式存在.下面就盐型氢化物的制备、性质及其在高考题中的应用做一介绍.[第一段]  相似文献   

4.
在2011年新课标全国卷第28题中考查了氢化物CaH2的制备、性质、用途.氢化物是氢与其他元素形成的二元化合物,在周期表中,除稀有气体外的元素几乎都可以和氢形成氢化物,氢化物大体分为离子型、共价型和过渡型三类,它们的性质各不相同.离子型氢化物也称盐型氢化物,是氢和碱金属、碱土金属中  相似文献   

5.
介绍了应用纳米氢化物制备高分子聚醚的方法,同时测定了试制聚醚的性能.考察了起始剂、引发剂、聚合单体配比和反应时间温度等条件对高分子聚醚的性质影响,得到抗老化性、溶解性、逆溶性、淬火冷却性能、增粘性都十分优秀的高分子聚醚.  相似文献   

6.
根据Randic的分子连通性拓扑方法,提出了一个新的分子拓扑指数Y,将P区氢化物PKa与分子拓扑指数Y相关联,复相关系数为0.9991,标准偏差为1.01,其计算公式为:PKa=34.94Y 32.03(1-q)rA-H^-1-44.53,式中rA-H为氢化物(HnA-H)分子中A-H键键长,q为氢化物所带电荷数,对近20个P区氢化物分子的酸性强度PKa进行了计算,理论值与实验值符合程度度,平均偏差为0.53,小于前人所有的方法。  相似文献   

7.
本文为学生阅读材料,介绍直接硼氢化物燃料电池,帮助一线教师实施新课标高中化学教学.  相似文献   

8.
元素及其化合物的知识在中学化学教材中占有较大的比例,内容繁多琐碎,在学习时要尽可能以最佳的方法或方式总结成网络图,主线明确、脉络清晰.每族元素抓住代表物.重点讨论该元素的单质、氧化物、氢化物、酸、碱或盐等有关知识;注意该族元素与其代表物在结构、性质上的相似性、递变性和特殊性.高考重点考查各族元素的单质及其化合物的性质,学习非金属元素时要理清非金属元素的性质及递变规律等问题.  相似文献   

9.
本文在研究氢化物分子中A-H键键能耐变化规律的基础上,运用分子原子结构参数提出了一个新的A-H键键能计算公式:DA-H^0=38.87φ 52.05φ2 φ3 32.5(Kcal/mol)[R=0.9993]。用该式计算了34个氢化物A-H键的键能,其计算值与实际值较吻合,新公式物理意义明确,计算方便,可靠性强。  相似文献   

10.
本文根据Randic的分子连通性拓扑方法,提出了一个新的分子拓扑指数Y,将P区氢化物酸性强度PKa与分子拓扑指数Y相关联,复相关系数为0.9991,标准偏差为1.01,其计算公式为:PKa=34.94Y 32.03(1-q)Y_(A-H)~(-1)-44.53式中Y_(A H)为氢化物(HnA一H)分子中A一H键键长,q为氢化物分子所带的电荷数.对近20个P区氢化物分子的酸性强度PKa进行了计算.理论值与实验值符合程度高,平均偏差为0.53,小于前人所有的方法.新方法形式简洁,计算方便,物理意义明确,很好地解释了P区氢化物酸性强度PKa的递变规律.  相似文献   

11.
What should be learned? How should it be organized for teaching? These seemingly simple questions are deceivingly political. Curriculum theorists are preoccupied with the politics of the first question at the expense of the realpolitik of the second. Instructional designers are preoccupied with the realpolitik of the second question at the expense of the politics of the first. I argue that conceptual distances between curriculum theory and instructional design are based on divisions of labour established during the 1960s. After decades of neglect, curriculum theorists, and specifically critical theorists, appear clueless when it comes to curriculum design and the realpolitik of their causes. When it comes to the realpolitik of practice their political causes are formless. Quite the opposite of critical theorists, instructional theorists nearly mastered the realpolitik of form but have no political causes. I argue that, to contradict the status quo of C&;I, curriculum theorists will have to dirty their hands with the realpolitik of form and instructional designers will have to clutter their heads with theory.  相似文献   

12.
理本论是朱熹哲学思想的核心和最高范畴,也是朱熹整个学术思想的核心和理论基础。这是一个具有客观唯心主义性质和伦理本位色彩的哲学范畴。其本体论哲学的构建是通过对传统文化中儒、道、佛三家思想的全面吸收和改造而完成的。具体讲:吸收佛学本体论的思维模式并将之改造为道德本体论;吸收儒学的道德学说并将之改造为伦理本位的哲学:吸收道家的认识论思想并将之改造为伦理体验的认识论。  相似文献   

13.
It is known by entropy theory that image is a source correlated with a certain characteristic of probability. The entropy rate of the source and ? entropy (rate-distortion function theory) are the information content to identify the characteristics of video images, and hence are essentially related with video image compression. They are fundamental theories of great significance to image compression, though impossible to be directly turned into a compression method. Based on the entropy theory and the image compression theory, by the application of the rate-distortion feature mathematical model and Lagrange multipliers to some theoretical problems in the H.264 standard, this paper presents a new the algorithm model of coding rate-distortion. This model is introduced into complete test on the capability of the test model of JM61e (JUT Test Model). The result shows that the speed of coding increases without significant reduction of the rate-distortion performance of the coder.  相似文献   

14.
A range of sociological work has theorized neoliberal regulative regimes, suggesting the contradictions contained in the enactment of policy and foregrounding the painful effects of these processes on subjectivities produced within performative school cultures. This paper contributes to this body of work by tracing the movement of desire in teaching assistants’ subjective relations to workplace practices of remuneration. We do this through an analysis of a series of group- and individual-free associative interviews with teaching assistants working in primary schools. Drawing on a Lacanian account of the way processes of identification channel affect, as desire, through signifying chains within a discursive field, we explore the associative chains of meaning that overdetermine the subjectivities produced within performative practices of remuneration. We suggest that the complex and contradictory chains of signification embodied in the school environment constitute a space where fragile teaching assistant subjectivities reiterate previous relations to an ambiguous Other.  相似文献   

15.
This article explores the question: Why are students of worth? Educationally, an answer often involves a Kantian response: They are of worth because they are always ends and never means. This response is usually connected to a notion of autonomy interpreted as individual, rational self-determination. The article argues for a different answer. The essay begins with a recent educational example of construing worth as rational autonomy. Meira Levinson, in her book The Demands of Liberal Education (1999), argues for a version of rational autonomy which is taken in the essay as a Kantian response to the question. The essay then turns to Kant’s own understanding of intrinsic human worth as ends. Although the essay agrees in general with the notion of end, it criticizes Kant’s version of rational autonomy. Instead, it argues for a notion of worth as irreplaceable singularity. Both the critique of the Kantian answer and theessay’salternative are shaped by the philosophy of Emmanuel Levinas. Here technical notions of “the other,” proximity and singularity are brought to bear on the question of human worth. The Levinasian alternative, so the essay argues, better answers the question of student worth by highlighting the incomparability of the student as a singular other.  相似文献   

16.
高校文化的内部功能有:(1)影响成员意识和规范成员行为,(2)增强学校凝聚力,(3)调节学校内部的社会关系;外部功能有:(1)利用组织意识指导学校与环境互动,(2)利用高校文化特征树立学校形象,(3)利用特定的高校文化适应环境。高校文化的内容包括:意识体系,制度性规范,行为基本模式,象征性符号和模范人物故事和传说等。高校文化的主要特征应与各校特有专业相联系。高校文化内部传播的目的是维持学校内部统一、实现整体协调和整体运作;外部传播的目的是突出本校的文化个性,给公众留下深刻的识别印象,扩大本校对,公众的影响力。  相似文献   

17.
本文主要讨论平移集合的最基本性质,即集合的并,合的平移性,集合的基数的平移性,集合的有界性的平移性,极值性的平移性,可数集合的平移性等问题。  相似文献   

18.
Theodore Dreiser is now regarded as one of the pre-eminent American realistic novelists of the first half of the twentieth century.an anatomist of the American Dream.In his great work An American Tragedy,Dreis- er exposes and criticizes mercilessly the corruption and black side of American society.The disillusionment of the American Dream is an important theme of the fiction.This paper illustrates "An American Tragedy" is the re- flection of disillusionment of the American Dream in the perspectives of the tragedy of a mortal,the tragedy of American society,and the tragedy of the American Dream.  相似文献   

19.
This paper discusses the most persistent controversial issue that occurred in Western educational philosophy ever since Socrates questioned the Sophists: the role of truth in teaching. Ways of teaching these kinds of controversy issues are briefly considered to isolate their epistemic characteristics, which will enable the interpretation of Plato and Dewey as exemplars of rationalism and empiricism regarding the role of knowledge in the curriculum and thus include their partial truths in the epistemic ethos of teaching. The consideration of pedagogy will then include the partial truths of rationalism and empiricism in the epistemic ethos of teaching by following Kant's 'Concepts without percepts are empty; perceptions without conceptions are blind'.
This claim, however, is narrowed down in two ways compatible with postmodernism and the heavy emphasis on constructionism in faculties of education. After quoting Harry Broudy's statement that the educational epistemic ethos should be domain-specific, guided by the experts' inquiry protocols in each curricular area, it is narrowed down further with Maxine Greene's explication that it should be pluralistic and lesson-specific. This epistemic ethos is not argued as a synthesis but as an aggregate of the partial truths of various epistemologies in the spirit of the postmodern doubt in any one theory of knowledge without throwing out the baby with the dirty bath water.
Finally, the streams of consciousness involved in teaching and learning good knowledge are described phenomenologically to disclose how truth can be disclosed in teaching, thereby grounding propositional knowledge, for example, ontologically in the being of the student and in the being of the world.  相似文献   

20.
Students have to be punished if they have made a serious transgression. Avoidance of punishment will lead to serious complications. But punishment is inseparably linked with guilt and forgiveness. The inability of individuals to forgive themselves was regarded by Kierkegaard to be an emanation of individual false pride, a kind of vanity. This type of despair, a psychological and spiritual disorder, is a serious and debilitating problem. The inability to escape this despair of forgiveness can lead to a loss of genuine humanness. Unchecked, this despair can lead to unrelatedness of self to itself and fear of the possibility of freedom. Thus the self-knowledge attainable in despair over the forgiveness of an offense would lead to what we would call a successful rehabilitation of the individual and his or her conjunct reintegration into society. Kierkegaard's ideas on punishment are interesting — historically and philosophically speaking — because they represent a softening of a harsh view of punishment by stressing the humanizing aspects of guilt and forgiveness.  相似文献   

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