问题情境的有效教学与思考

古语云：“学起源思，思起源疑．”数学问题情境是学生掌握知识，形成能力，培养理性思维，发展良好心理品质的重要源泉，是沟通现实生活与学习的桥梁．创设良好的“问题情境”，能激发学生的学习兴趣和动机，使学生产生“疑而未解，又欲解之”的强烈愿望，进而转化为一种对知识的渴求，为课堂教学创设一种紧张、活跃、和谐、生动、张驰有道的理想氛围．而在实际教学中，有些教师对问题情境设计关注不够、认识模糊，认为只有生活实例才是情境，似乎每节课都要实际情境引入，因而频频出现低效、无效、多余，乃至干扰学习的“假情境”．     

例谈数学概念教学中的和谐关系

一、探究与接受的和谐 探究学习比较开放，重点培养学生的问题意识和创新精神，更强调过程，在积累直接经验、培养学生的实践能力方面有其独到之处．但是，过分强调之，教学就会走向无目标的误区，演变为信马由缰的活动，概念教学中，在探究的基础上，教师适时地讲解，可以让学生在较短的时间内让学生积累更多的间接经验，针对学生个体中存在较大的差异，必要时教师充分利用多媒体、板演、强调、订正强化学生的认知水平．     

高考专题复习系列讲座（2）——数列、极限和数学归纳法

近几年高考试题中，数列、极限和数学归纳法始终占有比较大的比重，2007年全国高考19套（37份）数学试卷中，涉及这部分内容的题目共70道（小题34道，大题36道），分值平均占卷面总分的12％左右，大大超过了课时所占比重（仅约8％）．小题重点考查等差数列、等比数列以及数列的极限，大题则突出对递推思想、归纳方法、运算能力和推理论证能力的考查，常考的知识点有：数列的概念，数列的表示方法，数列的通项公式，等差（比）数列的定义、通项公式、前n项和公式、性质，递推数列，数列极限的定义，两个重要极限，无穷递缩等比数列的各项和公式，数学归纳法．此外，函数方程思想、从一般到特殊的思想、归纳与转化思想、递推方法等数学思想方法也是命题者关注的热点．     

他乡遇君分外亲

1983年深秋，一群已过而立之年的民办教师，怀着高考拼搏获胜后的欣喜，抖落掉满身的粉笔细末，从太行山麓的柿林，黄河两岸的竹乡，从九朝古都、二七煤城、中原油海，从殷墟之地、韩愈桑梓、岳鹏举家乡、朱载靖故里，沿着伏牛山的小径，追着红旗渠的浪花，跨过洪水上的小桥，汇聚到了一所高等师范专科学校。     

《高等数学研究》稿约

一、宗旨、内容、对象1、本刊是国家科技部批准，国内外公开发行的数学期刊。其宗旨主要是配合大学的数学教育，研究高等数学的理论、方法及应用，指导和帮助大学生更好地学习和理解大学数学的内容、方法和思想，提高大学生的数学素质，促进大学数学教学和素质教育水平的提高，为培养高素质的科技人才服务；同时，也为从事数学教学的一线教师和数学工作者，提供一片数学创作的园地，为繁荣我国数学事业服务。     

谈数学课堂教学中思维热点的组织

所谓思维热点，就是能够引起学生积极思维，对问题产生共鸣、诱发思维情趣的问题，教师组织课堂思维热点的关键，在于教师在教学设计时，要根据教材的内容、学生的实际和本人的教学特点．做到精心选材、精心设计、精心安排．一般地说，思维热点的组织安排，可以从以下几个方面来考虑。     

双剑合璧彰显数学之美

数学中，有一些概念、定义、定理在结构上、性质上、用途上颇为相似，存在紧密联系．它们就像数学大家庭中的一对对“伴侣”一样，相互融合、相互渗透又相互作用、相互对比，共同诠释着数学的奥妙．笔者以高中数学几个经典知识为例，从分析数学的角度，让这一对对数学伴侣“双剑合璧”，以彰显数学别样之美．一、正、余弦定理“双剑合璧”，彰显数学“证明”之美     

HARNACK'S INEQUALITIES FOR ANALYTIC OPERATOR FUNCTIONS

IllltllodllCtIOllLetHdenoteacomplexHllbertspace．LetB（H）beacomplexBanachspaceofallboundedlinearoperatorsonH，andB（H）”，thecolljugatespaceofB（H）．TherealandimaginarypartsofanoperatorAonXaredenotedbyReAandImA，respectively，l．e。D。A一T，、、A＿一Ti，＊＊，。、．．＿TT。－＿，。，、，、＿＿。、、。＿、。＾。＿，、、＿。，，、。＿＾。nireH”一十，lmH“＝－－－－－－．rortWOInirm1LlanOperaLOrSH．nOllrr。weWriteH5otoIndicatethatB—AIsapositiveoperator．i．e，（（B—A）。，…     

算盘功劳大 古今中外夸

珠算是以算盘为计算工具的一种实用科学技术，是我国古代五大发明之一，渊源流长，距今已有三千多年的历史。不论是过去、现在乃至未来都是人类不可缺少的科技，具有极其重要的战略意义。在其创建发展的历史长河中，为我国的政治、经济、军事、科学、文化、教育、心理、生理、卫生和人民日常生活等诸多方面，长期地发挥着巨大的作用。打算盘打出了许多绝活与奇迹，建立了许多丰功与伟绩。     

争鸣

本刊自2002年开办“争鸣”栏目以来，得到了广大读者的热情支持，提出了不少好的问题，本刊表示衷心感谢!为了进一步办好“争鸣”栏目，繁荣教学研究的大好局面，尽量避免在一些具体问题上因自然语言方面的歧义而导致的争论不清，本刊除了希望广大读者继续大力支持本刊，提供有关教学上的具体问题之外，还特别希望就一些大的方面也提出自己的问题，开展百家争鸣，如教学思想、理念、观点，对新课标、新教材、素质教育与高考等的不同意见，通过探讨，各抒己见，防止一种倾向掩盖另一种倾向，推动新一轮课改健康、深入地开展．     

Properties of the normset relating to the class group

In a recent paper by the author the normset and its multiplicative structure was studied. In that paper it was shown that under certain conditions (including Galois) that a normset has unique factorization if and only if its corresponding ring of integers has unique factorization. In this paper we shall examine some of the properties of a normset and describe what it says about the class group of the corresponding ring of integers.

     

正则化δ函数对浸入边界法精度的影响

浸入边界法是对流固耦合系统进行数学建模和数值模拟的有效工具,在生物力学领域的应用尤为广泛．正则化δ函数对精度的影响是研究浸入边界法本身性质的一个重要课题．采用虚拟解法对此展开分析．首先使用光滑虚拟解证明程序的正确性,然后使用压力存在跳跃的虚拟解研究浸入边界法的精度．通过分析使用4种不同的正则化δ函数时整个流场的离散误差,得到以下结论:浸入边界法只具有1阶精度;选用不同的正则化δ函数,不能提高浸入边界法的精度,但会影响整个流场的离散误差值．     

Textbooks revealing the development of a concept—the case of the number line in the analytic geometry (1708–1829)

The purpose of this paper is to use historical textbooks to explore the number line, a mathematical object common to our time, contextualizing its use during its initial development period in the seventeenth century until its current use as in the nineteenth century. Relevant analytic geometry textbooks are explored, mainly from France and from Germany of that time, to understand when and how this notion was used. Additionally, pertinent entries from encyclopedias of that time are used to contrast with what was not sufficiently explained in the aforementioned textbooks, until, finally, we can identify this object as it is currently characterized. I analyze how the negative numbers were used to constitute the number line and survey several number line diagrams, which were sometimes similar, but most often quite different from each other. The intention is to understand the historical contexts that configure the emergence and development of the notion of the number line.     

On the remarkable values of the rational first integrals of polynomial vector fields

The remarkable values for polynomial vector fields in the plane having a rational first integral were introduced by Poincaré. He was mainly interested in their algebraic aspects. Here we are interested in their dynamic aspects; i.e. how they contribute to the phase portrait of the system, to its separatrices, to its singular points, etc. The relationship between remarkable values and dynamics mainly takes place through the inverse integrating factor.     

油田开发指标系统的概率模拟预测

基于油田开发指标系统的复杂性和其影响因素带有明显的随机特征,从理论和实用上研究了油田开发指标系统的不确定性预测方法.方法提出采用神经网络建立开发指标和影响因素的关联关系;利用微分模拟研究开发指标的影响因素的概率分布;使用蒙特卡罗方法对影响因素进行随机抽样;依据得到的关联关系和影响因素的随机样本建立油田开发指标的概率预测模型.此外,设计了概率模拟器.实例研究表明开发指标的预测值以某概率落在某个区间内,这可为决策者做出符合实际的决策和准备应急决策方案提供依据.     

Reaching the Unreachable: Technology and the Semantics of Asymptotes

This work is part of a larger attempt to explore the nature of symbolic understanding involving graphic technology. This study describes learning advanced mathematics that occurs through constructing qualitative reasoning methods using graphic technology. Data was gathered from a precalculus class who, for a few weeks, investigated and explored asymptotic behavior of rational functions. The analysis is based on observations of group discussions and written works. Learning about asymptotes using software which serves as tool box for numerical evaluation and graphic representation amplifies epistemological complexities related to the infinity concept. Using the software to watch examples of rational functions, generated by symbolic and graphic operations between polynomial functions, enabled students to leave their own traces on the formalization of asymptotes – on its definition, its symbolic structure, and its computational procedures. The discrepancy between technology as a support for visual perception but a tool that cannot support theconception of approaching infinities, makes the study of asymptotes an intriguing domain for investigating what is being manipulated with software and how.This revised version was published online in September 2005 with corrections to the Cover Date.     

Convexity of the Implicit Lagrangian

The implicit Lagrangian has attracted much attention recently because of its utility in reformulating complementarity and variational inequality problems as unconstrained minimization problems. It was first proposed by Mangasarian and Solodov as a merit function for the nonlinear complementarity problem (Ref. 1). Three open problems were also raised in the same paper. This paper addresses, among other issues, one of these problems by giving the properties of the implicit Lagrangian and establishing its convexity under appropriate assumptions.     

Letter to the editor

It is shown that the recent characterization of strong feasibility of interval linear equations by Karademir and Prokopyev was in fact published by this author 13 years earlier. The original result was difficult to discover, having been embedded, together with its proof, into the proof of another theorem.     

结构方程模型与联立方程模型的比较

本文首先介绍了结构方程模型和联立方程模型的一般形式、典型实例及其在我国的研究现状。通过将结构方程模型与联立方程模型进行比较,发现结构方程模型具有能直接处理潜变量和测量误差等优点,在管理学、心理学等社会科学中具有广泛应用;但是结构方程模型对样本量要求大、对抽样、问卷设计和调查过程的缺陷以及忽略变量等模型的设定错误不能弥补;而且,结构方程模型的参数不如联立方程模型的含义那么具体而直观。     

Evolution of Bounding Functions for the Solution of the KPP–Fisher Equation in Bounded Domains

The KPP–Fisher equation was proposed by R. A. Fisher as a model to describe the propagation of advantageous genes. Subsequently, it was studied rigorously by Kolmogorov, Petrovskii, and Piskunov. In this paper, we study the dynamics of the KPP–Fisher equation in bounded domains by giving bounds on its solution. The bounding functions satisfy nonlinear equations which are linearizable to the heat equation. In addition to describing the dynamics of the KPP–Fisher equation, we also recover some previous results concerning its asymptotic behavior. We perform numerical simulations to compare the solution of the Fisher equation and the bounding functions.