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1.
危机应对术     
陈缨 《珠算》2009,(4):45-45
回忆去年的情况,用一段比较流行的话来说,基本上眼睛一闭一睁,发现世界变了,箭头的方向变了,指标的颜色变了,公司的形势变了,经营业绩变了。  相似文献   

2.
老歪的礼物     
《数学大王》2009,(7):25-25
放暑假了,庄库欢天喜地地和爸爸妈妈旅游去了,贝卡在Q岛上乐不思蜀,卡卡西被她朋友拉去逛街,正好遂了她的意,柯西探长视休息为无聊。只有老歪,学生不用上课了,看着空荡荡的教室和空荡荡的校园,他突然不知道该干啥了。  相似文献   

3.
阿摹米德(Archimcdes)古希腊数学家、物理学家,生于叙拉古(公元前287~212),他用了毕生精力专研数学,发展了穷竭法,解决了许多复杂的曲线求长问题,及曲面或曲面体的求积问题,他的极微穷竭思想,埘后来微积分的产生奠定了基础,同时他撰写了《抛物线的求积》、《论螺线》、……等五部巨著,故许多人认为,阿基米德是世界...  相似文献   

4.
这个地方原是部队演习基地,去年部队开发了更好的基地以后,将这里交给了地方政府,后来有家公司买得了此地的使用权,将它开发成了一个集度假,拓展训练,探险于一体的野外活动基地。  相似文献   

5.
我校建筑经济设置的计算课程,按照教学大刚要求,珠算技术达标水平由原来的普通六级提高到五普通级,这就为教学工作提出了新的要求,增加了教学难度,为此,经过教学实践摸索,进行了因材施教.分类指导.普遍提高的教学方法的尝试,收到了较好的效果。  相似文献   

6.
猜想是数学发展的不竭动力,就如那哥德巴赫猜想,跨越了千年,而今仍旧无法完全证明,但正是有了“猜想”这个神奇的动力,才让它一点点的被完善,一点点韵进步.数学亦是如此,正因为有了数学猜想才让它更具魅力.数学猜想不但促进了数学的理论的发展,也促进了数学方法的应用和研究以及数学发展的历史,  相似文献   

7.
有幸听到了一节几何概型的公开课,学生配合默契投入,课堂气氛和谐愉快,师生互动风落水上。自然成纹,听课教师如沐春风,耳目一新,更坚定了我们开展探究性学习的信心.这节课通过学生自主学习、主动思考、合作交流、归纳总结,使学生对知识的发生、发展有了切身的感受和清晰的理解,同时也提高了课堂效率,培养了学生的创新能力和实践能力,学生的才智和各种潜能也得到了充分的展示和发挥.  相似文献   

8.
每文 《数学大王》2013,(12):15-17,39
晚上的一场大雨,让酷热的小镇稍微清凉了一些。不过,后半夜雨就停了,太阳照常升起,才8点钟,地面就已被烤干,完全看不出下过雨的痕迹了。福尔摩西刚到办公室,就接到了一起钻石失窃案的报警电话。  相似文献   

9.
2008年湖北高考数学试卷贯彻了《考试大纲》和《补充说明》的考试要求,融入了新课程理念,较好的体现了“平稳中重基础、朴实中显特色”的命题思想.全卷题型布局稳中求变,选择题、填空题坡度适当,解答题难易适中,应用题新旧兼顾,探究能力动态考查,合情推测之中隐含着深刻的数学背景.与2007年相比,笔者认为命题更加成熟、规范,正视了文理科考生的差异,合理的设计了文理科试卷的难度系数,  相似文献   

10.
《珠算》2011,(1):68-69
各位同仁:你们好! 过去十几年,是中国的高速发展时代。中国经济迅速崛起,创造了举世注目的经济奇迹。而大量的中国民营企业,历经多年艰难创业,也铸就了辉煌的事业,制造了无数的财富神话。百度,腾讯,携程,新东方,阿里巴巴这些耳熟能详的创业故事,又鼓舞了无数后来者继续在这个激动人心的时代续写更多辉煌创业篇章。  相似文献   

11.
In this research, we develop and introduce a theoretical and mathematical forecasting framework of immigrant integration using immigrant density as a single driver. First, we introduce the integration concepts we aim at forecasting. Thereafter, we introduce a theoretical and mathematical model of the relationship between integration and immigrant density. Based on this model, we develop a methodological forecasting framework. We test the framework using immigrant integration data from Spain. We produce the forecasts, and conduct the proper evaluation of them. Finally, we conclude with a brief discussion of the wider implications of our results.  相似文献   

12.
Optimal control of nonlinear evolution inclusions   总被引:1,自引:0,他引:1  
In this paper, we study the optimal control of nonlinear evolution inclusions. First, we prove the existence of admissible trajectories and then we show that the set that they form is relatively sequentially compact and in certain cases sequentially compact in an appropriate function space. Then, with the help of a convexity hypothesis and using Cesari's approach, we solve a general Lagrange optimal control problem. After that, we drop the convexity hypothesis and pass to the relaxed system, for which we prove the existence of optimal controls, we show that it has a value equal to that of the original one, and also we prove that the original trajectories are dense in an appropriate topology to the relaxed ones. Finally, we present an example of a nonlinear parabolic optimal control that illustrates the applicability of our results.This research was supported by NSF Grant No. DMS-88-02688.  相似文献   

13.
Orthogonal polynomials satisfy a recurrence relation of order two defined by two sequences of coefficients. If we modify one of these recurrence coefficients at a certain order, we obtain the so-called perturbed orthogonal sequence. In this work, we analyse perturbed Chebyshev polynomials of second kind and we deal with the problem of finding the connection coefficients that allow us to write the perturbed sequence in terms of the original one and in terms of the canonical basis. From the connection coefficients obtained, we derive some results about zeros at the origin. The analysis is valid for arbitrary order of perturbation.  相似文献   

14.
We develop a general setting for the treatment of extensions of categories by means of freely adjoined morphisms. To this end, we study what we call composition graphs, i.e. large graphs with a partial binary operation on which we impose only rudimentary requirements. The quasicategory thus obtained contains the quasicategory of all categories as a full reflective subquasicategory; we characterize composition graphs for which this reflexion is of a particularly simple nature.This leads to the concept of semicategory; we apply semicategories to solve characterization problems concerning absolutely initial sources, absolute monosources and potential sections. For instance, we show that in any category, the absolutely initial sources are precisely the sources that contain a section.  相似文献   

15.
In this paper, we introduce the concept of capability for crossed modules of Lie algebras, which is a generalization of capability in Lie algebras and groups. By using a special central ideal of a crossed module, we give a sufficient condition for the capability of a crossed module of Lie algebras. Also, we will extend the five-term exact sequence on homology of crossed modules of Lie algebras one term further and study the connection between the capability of crossed modules and this sequence. Finally, we study the relation between the capability and the center of a cover of a crossed module.  相似文献   

16.
何树红 《数学研究》1999,32(1):1-13
本文通过引入一类Frechet空间,证明了一类与流体力学有关的非线性发展方程的弱解存在着整体吸引子.  相似文献   

17.
Nonlinear fractional differential-algebraic equations often arise in simulating integrated circuits with superconductors. How to obtain the nonnegative solutions of the equations is an important scientific problem. As far as we known, the nonnegativity of solutions of the nonlinear fractional differential-algebraic equations is still not studied. In this article, we investigate the nonnegativity of solutions of the equations. Firstly, we discuss the existence of nonnegative solutions of the equations, and then we show that the nonnegative solution can be approached by a monotone waveform relaxation sequence provided the initial iteration is chosen properly. The choice of initial iteration is critical and we give a method of finding it. Finally, we present an example to illustrate the efficiency of our method.  相似文献   

18.
Summary We investigate the following problem: To influence a heat conduction process in such a way that the conductor melts in a prescribed manner. Since we treat a linear auxiliary problem, it suffices to deal with a linear-quadratic defect minimization problem with linear restrictions, where we use splines or polynomials as approximation spaces. In case of exact controllability we derive various order of convergence estimates, which we discuss for some numerical examples.  相似文献   

19.
Monoids and acts which may have zero elements are considered. In Section 1 we construct a O-wreath product of monoids. In 2 we prove the theorem that the endomorphism monoid of a free act over a monoid with zero can be represented as a O-wreath product. Considering monoids with tero we are interested in their annihilator properties. In 3 we give necessary and sufficient conditions for a O-wreath product of monoids to be a right (left) Baer (Rickart) monoid. In 4 we obtain as a consequence corresponding conditions for the endomorphism monoid of a free act over a monoid with zero.  相似文献   

20.
In this paper we shall present the optimization problem in a set of solutions of operator inclusion with the maximal monotone operator. Then we treat optimization problem by Galerkin method and we prove convergence of optimal values of approximated optimization problems to the one for the original problem. Finally, we apply the results to give a simple example.  相似文献   

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