从2015年陕西高考试题管窥“现在完成进行时态”的语用功能

"现在完成时态"的"完成"概念可分"未最终完成"与"最终完成"两个阶段。"进行时态"的语用功能从共时性角度可以分为"同时性"、"几乎同时性"以及"持续性"三个类型。当这些特性与现在完成时态结合的时候,就会依次表明,相关动词正在践行的时间与句子中的时间状语所反映的时间完全重合、相关动词正在践行的时间与言语双方的心里时间"几乎重叠"以及一个"一直持续且未完成"的行为过程。     

《大学数学》征稿启事

<正>一、《大学数学》是由教育部主管,大学数学课程教学指导委员会、高等教育出版社有限公司、合肥工业大学联合主办的全国性教学与科研相结合的数学刊物。二、本刊设有"理论与方法"、"数学应用"、"专题研究"、"教学研究与改革"、"计算机辅助教学"、"教材建设"、"思维与能力培养"、"数学建模"、"教学研究"等栏目。     

《大学数学》征稿启事

<正>一、《大学数学》是由教育部主管,大学数学课程教学指导委员会、高等教育出版社有限公司、合肥工业大学联合主办的全国性教学与科研相结合的数学刊物。二、本刊设有"理论与方法"、"数学应用"、"专题研究"、"教学研究与改革"、"计算机辅助教学"、"教材建设"、"思维与能力培养"、"数学建模"、"教学研究"等栏目。三、本刊的读者对象是数学工作者,大专院校师生,有关科技人员和其他数学爱好者。     

错题“改、变、串”的教学实践与研究

课堂教学的本质是以知识为基本媒介,引导学生学会"如何思"、"如何想",并走向"自觉地思"、"自觉地想"的过程,是一个不断把学生带入"思"的状态中去的过程.错题"改、变、串"的变式教学是对传统变式教学的继承与发展,"改"即为"改题","变"即为"变式","串"即为"串联",这些是对"变"的主权释放,是对课堂教学本质的很好体现,引导学生从"变"的现象中发现"不变"的本质,从"不变"     

“多1”与“少1”的“惑”和“祸”

几次珠心算质量分析会上,教师们不约而同谈得最多的是学生"多1"与"少1"方面的困惑。有经验的教师竭尽全力、想尽一切办法,对"多1"与"少1"进行围追堵截,但还是不尽人意;没经验的教师则被"多1"与"少1"捆绑住了手脚,不知所措。一、"多1""少1"带来的"惑"大部分教师认为难学易错的主要原因是"粗心、练习过少"所造成的,真的仅仅是因为这些原因吗?其实,错误反映出孩子认知上存在着偏差,也反映出孩子学习困难所在     

《大学数学》征稿启事

<正>一、《大学数学》是由教育部主管,大学数学课程教学指导委员会、高等教育出版社有限公司、合肥工业大学联合主办的全国性教学与科研相结合的数学刊物。二、本刊设有"理论与方法"、"数学应用"、"专题研究"、"教学研究与改革"、"计算机辅助教学"、"教材建设"、"思维与能力培养"、"数学建模"、"教学研究"等栏目。三、本刊的读者对象是数学工作者,大专院校师生,有关科技人员和其他数学爱好者。四、来稿要求和注意事     

积分型Cauchy中值函数若干分析性质

给出"积分型Cauchy中值函数"的定义,对"积分型Cauchy中值函数"的分析性质进行了系统讨论,证明了"积分型Cauchy中值函数"的单调性、可积性、连续性、可微性等分析性质.作为"积分型Cauchy中值函数"的特例,给出了"第一积分中值函数"的定义及"第一积分中值函数"相应的分析性质.     

《大学数学》征稿启事

<正>一、《大学数学》是由教育部主管,大学数学课程教学指导委员会、高等教育出版社有限公司、合肥工业大学联合主办的全国性教学与科研相结合的数学刊物。二、本刊设有"理论与方法"、"数学应用"、"专题研究"、"教学研究与改革"、"计算机辅助教学"、"教     

将浪漫诗意融入数学课堂

数学以缜密、严谨、规范著称,似乎与"僵化、刻板、枯燥"搭界,由此看来,数学真的与浪漫诗意"绝缘"了吗?我们说:不!一、"诗"和"诗意"首先需简单了解一下"诗"和"诗意"的无穷魅力、精神价值和存在意义《.现代汉语词典》说:"诗是反映生活、抒发感情的具有韵律性的文字."西南师范大学中国新诗研究所所长     

如何在数学概念教学中实现“过程性目标”

1提出问题《普通高中数学课程标准(实验)》(以下简称《标准》)首次将教学目标分成三个方面:即知识与技能目标,过程与方法目标,情感、态度与价值观目标,其中把"过程与方法"作为课程目标是本次课程改革的最大变化之一.在以前的《大纲》中,都在不同程度上强调了"过程与方法"的重要性,但是,这次课程改革把"过程与方法"作为课程目标.这样"过程与方法"不再是可有可无的东西,而是必须实现的基本目标.《标准》在"课程的基本理念"中涉及的"过程性目标"的论述有很多,我们不难发现,以"经历"、"体验"、"模仿"、"体会"、"发现"、"探索"等为标志的过程性目标,关注他们的学习过程、学习形式、学习方法、提高兴趣、树立信心、开拓视野、培养习     

围绕财经特色主题 加强《高等代数》精品课程建设

我校精品课程《高等代数》建设的思路是,围绕财经特色主题,坚持以高等代数理论为基础,以经济、管理类的专业为依托,以数学实验室为训练基地,将数学建模的思想融入到《高等代数》的教学活动中.这种教学模式的改变不仅有利于学生的培养,而且有助于培养出一支有较高水平的师资队伍.使我们的《高等代数》课程真正成为高水平、高质量的示范性课程.     

On the domain dependence of solutions to the two-phase Stefan problem

We prove that solutions to the two-phase Stefan problem defined on a sequence of spatial domains _n ^N converge to a solution of the same problem on a domain where is the limit of _n in the sense of Mosco. The corresponding free boundaries converge in the sense of Lebesgue measure on ^N.     

Positive commutators at the bottom of the spectrum

Bony and Häfner have recently obtained positive commutator estimates on the Laplacian in the low-energy limit on asymptotically Euclidean spaces; these estimates can be used to prove local energy decay estimates if the metric is non-trapping. We simplify the proof of the estimates of Bony-Häfner and generalize them to the setting of scattering manifolds (i.e. manifolds with large conic ends), by applying a sharp Poincaré inequality. Our main result is the positive commutator estimate

     

Uniqueness of the Kontsevich-Vishik trace

Let be a closed manifold. We show that the Kontsevich-Vishik trace, which is defined on the set of all classical pseudodifferential operators on , whose (complex) order is not an integer greater than or equal to , is the unique functional which (i) is linear on its domain, (ii) has the trace property and (iii) coincides with the -operator trace on trace class operators.

Also the extension to even-even pseudodifferential operators of arbitrary integer order on odd-dimensional manifolds and to even-odd pseudodifferential operators of arbitrary integer order on even-dimensional manifolds is unique.

     

关于敏感动力系统以及从表观决定过程向完全随机过程的过渡

本文详细分析了掷硬币的动力学过程,通过计算研究了最终位形(即正、反面)究竟如何敏感地依赖于初始条件以及造成这种敏感性的原因.结果也表明,随着硬币质心初始高度h的增加,最终位形对于初始参数(初始方位.初始角速度等)、桌面的能量吸收因子以及空气阻力系数等变得越来越敏感.如果我们在初始时刻保持“正面”向上.但允许某些其它参数有一个微小的变化范围,那么,当h小(与硬币半径相比)时.最终位形为“正面”的频率为1:当h非常大时,该频率接近于1/2.一个有趣的问题是:当h从零开始连续增加时,这个频率怎样从1连续地过渡到1/2?仔细计算表明,这个“过渡”与从层流到湍流的过渡颇为相似.本文指出了“过渡阶段”与“完全随机阶段”的基本区别:在“完全随机阶段”,单个情形的决定性过程对初始条件和动力学参数极端敏感,而系综的统计性质则对初始条件和动力学参数的微小变化不敏感;与此相反,在“过渡阶段”,单个情形的决定性过程和系综的统计性质对初始条件和动力学参数都敏感.造成过渡阶段这一特点的机制是在参数空间中存在着“长链结构”.本文还讨论了这一分析对其它随机现象可能具有的启示.     

On the lack of null-controllability of the heat equation on the half-line

We consider the linear heat equation on the half-line with a Dirichlet boundary control. We analyze the null-controllability problem. More precisely, we study the class of initial data that may be driven to zero in finite time by means of an appropriate choice of the boundary control. We rewrite the system on the similarity variables that are a common tool when analyzing asymptotic problems. Next, the control problem is reduced to a moment problem which turns out to be critical since it concerns the family of real exponentials in which the usual summability condition on the inverses of the eigenvalues does not hold. Roughly speaking, we prove that controllable data have Fourier coefficients that grow exponentially for large frequencies. This result is in contrast with the existing ones for bounded domains that guarantee that every initial datum belonging to a Sobolev space of negative order may be driven to zero in an arbitrarily small time.

     

Order of the Epstein Zeta-Function in the Critical Strip

Let Q(x₁,...,x_k) be a positive quadratic form of k2 variables and let (s,Q) be the Epstein zeta-function of the form Q. The growth rate of (s,Q) on the line Re s = (k–1)/2 is investigated. For k4 and for an integral form Q, the problem is reduced to a similar problem on the behavior of the Dirichlet L-series on the line Re s = 1/2. In the case k=3, the diagonal form over is investigated by the van der Corput method. For k=2, the known result due to Titchmarsh is re-proved by using a variant of the van der Corput method given by Heath-Brown. Bibliography: 9 titles.     

On the non-smoothness of the vector fields for the dynamically invariant Beltrami coefficients

For \(\mu \in L^{\infty }(\Delta )\), the vector fields on the unit circle determined by \(\mu \) play an important role in the theory of the universal Teichmüller space. The aim of this paper is to give some characterizations of the vector fields induced by dynamically invariant \(\mu \). We show that those vector fields are not contained in the Sobolev class \(H^{3/2}\). At last, we give some results on dynamically invariant vectors to show that the vector fields, the quasi-symmetric homeomorphisms, and the quasi-circles are closely related.     

On the Modelling of the Adoption of Process Innovations

An alternative view on the modelling of diffusion processesof process innovations has been introduced by Nooteboom (1989). Thebasic idea in that paper is to model the process of adoption ofprocess innovations as a gambling model with odds in favourdepending on expected returns and odds against depending on risk.In this paper it is investigated under which theoretical conditions posed on the expected return function the usual adopted assumptions Nooteboom (1989) with respect to the parameters of the gambling model are in fact reasonable. It is shown that only under certainconditions the assumptions made on the gambling model are true ontheoretical grounds. In all other cases a nonexample shows that theresults as mentioned in literature are in general not true.     

On the derivatives of the Berezin transform

Improving upon a recent result of L. Coburn and J. Xia, we show that for any bounded linear operator on the Segal-Bargmann space, the Berezin transform of is a function whose partial derivatives of all orders are bounded. Similarly, if is a bounded operator on any one of the usual weighted Bergman spaces on a bounded symmetric domain, then the appropriately defined ``invariant derivatives' of any order of the Berezin transform of are bounded. Further generalizations are also discussed.