关于理工科大学生理解反证法问题的调查

通过问卷调查，了解到理工科学生理解反证法的状况，绝大多数人会用反证法，但他们不知道反证法的理论依据．本文分析产生这种状况的原因，建议给学生介绍逻辑知识、反证法发展的来龙去脉及反证法在科学研究与实践中的作用等知识来改变这种情况。     

重视反证法思想的早期渗透

反证法是有效的数学证明方法之一,它不仅对数学科学体系自身的完善有促进作用,而且对人的思维能力的培养和提高也有极其重要的作用.反证法教学历来是中学数学教学的难点,这为诸多因素所致,如有些数学教师对反证法原理不完全理解,误以为“反证法就是证明逆否命题”,学生对学习反证法所涉及的知识掌握不牢固等,没有重视和搞好早期渗透也是一重要方面.本文在总结反证法教学现状的基础上,提出了早期渗透的观点,并对其必要性和可行性作了一些探究.     

浅谈反证法在高等数学中的应用

反证法是一种间接证法,其思维特点是逆向思维,这种方法不从命题的题设出发,而是从命题题断的反面入手,通过合理论证找出矛盾,从而确认命题的真实性.反证法的思想非常深刻,方法也相当灵活.但因它是一个逆向思维,初学者常常不习惯,也不得要领,有的甚至避而不用,其实反证法是证题术中一个有力的论证手段,它除了论证的功能外,还有发现的功能,本文就高等数学中几类常见的例题谈谈反证法在高等数学中的应用.     

反证法在静电学教学中的应用

讨论了反证法在静电学中的应用问题，说明反证法是训练学生思维品质的重要方式之一．     

几种反证法的转换问题

引言反证法是数学证明的重要方法之一。也是中学数学教学的难点之一。反证法与直接证法在一定条件下能否互相转化,怎样使学生在熟悉直接证法的基础上,很快地理解和掌握反证法,都是应当探讨的问题。本文将从数理逻辑角度探讨几种类型的反证法与直接证法之间、反证法与反证法之间的一些互相转化问题。并在这个基础上,谈谈个人对改进反证法教学方面的几点建议。为了便于叙述,先来观察几个具体的例子。     

几种反证法的转换问题

引言反证法是数学证明的重要方法之一,也是中学数学教学的难点之一。反证法与直接证法在一定条件下能否互相转化,怎样使学生在熟悉直接证法的基础上,很快地理解和掌握反证法,都是应当探讨的问题。本文将从数理逻辑角度探讨几种类型的反证法与直接证法之间、     

《机械设计基础》课程教学内容改革的探讨——谈关于在教学过程中引入相关先进制造技术知识的思索

针对目前学生在学习<机械设计基础>课程时缺乏兴趣和主动性这种状况,探讨在教学中采用引入相关先进制造技术知识大力开展计算机辅助设计的方法,调动学生的学习兴趣、增强实用性意识,创造一个学生主动学习基本知识、基本技能的局面.     

反证法在高等代数解题中的应用

高等代数是数学专业的一门重要基础课程,其解决问题的方法千变万化,而反证法是对数学命题进行间接证明的一种有效方法,在高等代数一些解题中,灵活运用反证法,往往会使用解题变得简洁明快.本文对反证法在高等代数解题中的应用进行了研究,通过一些实例总结了反证法在解高等代数问题的几个方面的应用.     

运用反证法应注意的几个问题

运用反证法应注意的几个问题邱育锋在数学论证中，被人誉为最精良武器之一的反证法在学生中却往往感到既方便，又难以驾驭。一方面数学中的许多定理和命题经常运用反证法证之，另一方面，什么样的问题适宜用反证法解决，使用该方法的关键如何把握却常叫人为难。本文从反证...     

谈谈反证法的教学

反证法是初等数学中重要的推理方法之一，它在数学中有广泛的应用。但比较抽象，容易造成思维定式，教学中应注意不失时机地渗透反证法的依据和原理，才能使学生灵活掌握，提高应用反证法去解决代数、几何中的一些问题的能力。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the