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1.
Conclusions As the result of a change in the deformation characteristics of the elementary layers, which is asymmetric with respect to the middle plane of the composite, and caused by imperfections of technical character, aging, the effect of temperature, moisture content, corrosive media, and other factors, the balancing of the laminated polymeric composites is disturbed. Formulas were obtained for determining all the pliability and rigidity matrix components of a nonbalanced monoclinic composite from known deformation characteristics, volume, and order of packing of the elementary layers.Institute of Wood Cellulose Chemistry, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1030–1035, November–December, 1976.  相似文献   

2.
The contributions to the philosophy and history of mathematics of one of the most eminent contemporary mathematicians, A. N. Kolmogorov, are analyzed. Although these contributions are not numerous, they contain discussions of the gradual generalization of the subject of mathematics, a partition of the development of mathematics—in particular, of the theory of probability—into periods, and, also, an evaluation of the works of a number of great savants, such as Newton, Lobatchevsky, etc.  相似文献   

3.
Mathematical writers, above all, Euclid, tend to present their theorems as decontextualized, abstract propositions, which has become the standard modus of textual presentation in theoretical mathematics. Mathematical commentators, however, provide their readers with personal names and historical facts in order to elucidate problems, provide contexts of discovery, or construct doxographies, among other things. Modern readers have used such information for the construction of histories of science. When we look at these passages, however, we see that personal names and information about mathematicians of the past can serve quite a range of different objectives, such as the strategic self-positioning of the commentator vis-à-vis the past or present of mathematics, the education of the reader, mathematical or moral, the construction of the history of the field, etc. Not only does the commentator present a persona of himself to the reader, he can also turn colleagues and predecessors into personae. This paper attempts to elucidate the practice, by offering four examples of such plays of and with personae, in Pappus, Eutocius, al-Nayrīzī, and Proclus.  相似文献   

4.
In this paper, the authors review origins, motivations, and generalizations of a series of inequalities involving finitely many exponential functions and sums. They establish three new inequalities involving finitely many exponential functions and sums by finding convexity of a function related to the generating function of the Bernoulli numbers. They also survey the history, backgrounds, generalizations, logarithmically complete monotonicity, and applications of a series of ratios of finitely many gamma functions, present complete monotonicity of a linear combination of finitely many trigamma functions, construct a new ratio of finitely many gamma functions, derive monotonicity, logarithmic convexity, concavity, complete monotonicity, and the Bernstein function property of the newly constructed ratio of finitely many gamma functions. Finally, they suggest two linear combinations of finitely many trigamma functions and two ratios of finitely many gamma functions to be investigated.  相似文献   

5.
Based on the study of the kinetics of deformation or rigidity, of the rise in temperature, and of the fracture surfaces, the article describes the mechanism of failure of plastics. It as found that in a cyclically loaded solid there occur two processes: strengthening and loss of strength. The main factors affecting strengthening in fatigue were discovered. Among them are the structure of the material, the degree of crystallinity, the load level, conditions of deformation, etc. The kinetics of rigidity can yield the most accurate information providing an idea of the process of fatigue failure of plastics.Paper read at the 9th International Conference on the Mechanics of Composite Materials, Riga, October, 1995.Kaunas Technological University, Lithuania. Translated from Mekhanika Kompozitnykh Materialov, Vol. 32, No. 2, pp. 279–285, March–April, 1996.  相似文献   

6.
Author's summary of a dissertation submitted for the degree of Doctor of Physicomathematical Sciences. The dissertation was defended February 10, 1970, at a meeting of the Scientific Council of the Institute of Applied Mathematics, Academy of Sciences of the USSR. Official opponents: B. V. Gnedenko, Academician of the Academy of Sciences of the USSR, Yu. V. Prokhorov, Corresponding Member of the Academy of Sciences of the USSR, and N. N. Chentsov, Doctor of Physicomathematical Sciences.Translated from Matematicheskie Zametki, Vol. 8, No. 3, pp. 393–407, September, 1970.  相似文献   

7.
给出了判断单形五"心"的一组向量形式的充要条件,并以单形ΣA={A0,A1,…,An}的重心为坐标起点,以此单形的n个顶点A0,A1,…,Ak-1,Ak+1,…,An(k=0,1,…,n)为终点的向量为基底,给出了单形中关于超球的心距向量公式,同时进一步研究了这些特征向量的有趣的几何性质.  相似文献   

8.
This paper is a review by the author of his dissertation, presented in competition for the academic degree of Doctor of Physicomathematical Sciences. This dissertation was defended on December 20, 1973 at the Scientific Council of the Institute of Mathematics, Siberian Branch, Academy of Sciences of the USSR. The examining committee consisted of Professor A. G. Kostyuchenko, Doctor of Physicomathematical Sciences; Professor A. F. Leont'ev, Corresponding Member of the Academy of Sciences of the USSR; and Professor M. K. Fage, Doctor of Physicomathematical Sciences.Translated from Matematicheskie Zametki, Vol. 16, No. 4, pp. 669–680, October, 1974.  相似文献   

9.
Specific features of SHS materials as the objects of rheology are discussed, various types of viscosimetric flows and the choice of rheological variables are delineated, a technique of constructing isochoric rheological curves for porous bodies is illustrated, and their possible types are reported. Such factors as nonuniformity of the porosity distribution external friction, and nonisothermality of the process are considered. A compression rheometer intended for studying the compaction kinetics and rheological properties of the SHS materials is described.Presented at the Ninth International Conference on the Mechanics of Composite Materials, Riga, October, 1995.Institute of Structural Macrokinetics, Russian Academy of Sciences, Moscow Region. Institute of Chemical Physics. Russian Academy of Sciences. Moscow Region. Translated from Mekhanika Kompozitnykh Materialov, Vol. 32, No. 2, pp. 265–269, March–April, 1996.  相似文献   

10.
Brown和McCoy在文[1]中建立了(F,Ω)-群的根理论,并由此考察了环的BrownMcCoy-根及其它一些根,根据这一方法,Szsz在文[2]中引进了环的(k,l,m,n)-根,其中k,l,m,n是任意的非负整数,并证明了环的Brown-McCoy根与(1,1,1,1)-根,(1,1  相似文献   

11.
当多值随机微分方程的扩散及漂移系数满足利普希兹连续性条件时,我们考虑其解的无穷小生成元问题.为了找出该无穷小生成元的核,我们研究了对应的多值椭圆方程及其粘性解.  相似文献   

12.
This paper contains a survey of papers on the geometry of differential equations, which appeared no earlier than 1972, continuing the general survey (RZhMat, 1974, 11A800), and considers in more detail a special cycle of investigations of the geometry of systems of partial differential equations, distinguished by the presence of practical applications. Then we continue the survey of new results on the geometry of an ordinary differential equation of arbitrary order, started in (RZhMat, 1978, 1A645). There is constructed a general theory of invariants of equations, and classes of equations admitting a simplified coordinate representation are invariantly distinguished.Translated from Itogi Nauki i Tekhniki, Seriya Problemy Geometrii, Vol. 12, pp. 127–164, 1981.  相似文献   

13.
本文提出岭回归估计的向量参数方法,选择均方误差函数的负梯度方向作为参数向量方向,根据均方误差与拟合误差的预期约束条件选择确定参数向量模长.文中获得了两个单调性结论,向量参数岭回归估计的均方误差是参数向量模长的单调减函数,而拟合误差是参数向量模长的单调增函数.基于两类误差的单调性结论,本文创建了关于两类误差的预期约束条件,预期条件约束下的向量参数岭回归方法有望成为兼备均方误差次优与拟合误差适度的双赢估计.文章最后是一个应用实例.  相似文献   

14.
Saunders Mac Lane has drawn attention many times, particularly in his book Mathematics: Form and Function, to the system of set theory of which the axioms are Extensionality, Null Set, Pairing, Union, Infinity, Power Set, Restricted Separation, Foundation, and Choice, to which system, afforced by the principle, , of Transitive Containment, we shall refer as . His system is naturally related to systems derived from topos-theoretic notions concerning the category of sets, and is, as Mac Lane emphasises, one that is adequate for much of mathematics. In this paper we show that the consistency strength of Mac Lane's system is not increased by adding the axioms of Kripke–Platek set theory and even the Axiom of Constructibility to Mac Lane's axioms; our method requires a close study of Axiom H, which was proposed by Mitchell; we digress to apply these methods to subsystems of Zermelo set theory , and obtain an apparently new proof that is not finitely axiomatisable; we study Friedman's strengthening of , and the Forster–Kaye subsystem of , and use forcing over ill-founded models and forcing to establish independence results concerning and ; we show, again using ill-founded models, that proves the consistency of ; turning to systems that are type-theoretic in spirit or in fact, we show by arguments of Coret and Boffa that proves a weak form of Stratified Collection, and that is a conservative extension of for stratified sentences, from which we deduce that proves a strong stratified version of ; we analyse the known equiconsistency of with the simple theory of types and give Lake's proof that an instance of Mathematical Induction is unprovable in Mac Lane's system; we study a simple set theoretic assertion—namely that there exists an infinite set of infinite sets, no two of which have the same cardinal—and use it to establish the failure of the full schema of Stratified Collection in ; and we determine the point of failure of various other schemata in . The paper closes with some philosophical remarks.  相似文献   

15.
On the basis of the solution of a series of problems of the distribution of static and dynamic fields of various physical kinds in the microstructure of composite materials reinforced with dispersed particles or fibers analogies are established between the stress, displacement, temperature, electromagnetic, and other fields subject to certain similarity criteria imposed on the properties of the components.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1028–1037, November–December, 1969.  相似文献   

16.
Lebesgue proved in 1940 that each 3-polytope with minimum degree 5 contains a 5-vertex for which the set of degrees of its neighbors is majorized by one of the following sequences(6, 6, 7, 7, 7), (6, 6, 6, 7, 9), (6, 6, 6, 6, 11)(5, 6, 7, 7, 8), (5, 6, 6, 7, 12), (5, 6, 6, 8, 10), (5, 6, 6, 6, 17)(5, 5, 7, 7, 13), (5, 5, 7, 8, 10), (5, 5, 6, 7, 27), (5, 5, 6, 6,∞), (5, 5, 6, 8, 15), (5, 5, 6, 9, 11)(5, 5, 5, 7, 41), (5, 5, 5, 8, 23), (5, 5, 5, 9, 17), (5, 5, 5, 10, 14), (5, 5, 5, 11, 13).We prove that each 3-polytope with minimum degree 5 without vertices of degree from 7 to 10 contains a 5-vertex whose set of degrees of its neighbors is majorized by one of the following sequences: (5, 6, 6, 5, ∞), (5, 6, 6, 6, 15), and (6, 6, 6, 6, 6), where all parameters are tight.  相似文献   

17.
Summary We consider the numerical solution of indefinite systems of linear equations arising in the calculation of saddle points. We are mainly concerned with sparse systems of this type resulting from certain discretizations of partial differential equations. We present an iterative method involving two levels of iteration, similar in some respects to the Uzawa algorithm. We relate the rates of convergence of the outer and inner iterations, proving that, under natural hypotheses, the outer iteration achieves the rate of convergence of the inner iteration. The technique is applied to finite element approximations of the Stokes equations.The work of this author was supported by the Office of Naval Research under contract N00014-82K-0197, by Avions Marcel Dassault, 78 Quai Marcel Dassault, 92214 St Cloud, France, and by Direction des Recherches Etudes et Techniques, 26 boulevard Victor, F-75996 Paris Armées, FranceThe work of this author was supported by Avions Marcel Daussault-Breguet Aviation, 78 quai Marcel Daussault, F-92214 St Cloud, France and by Direction des Recherches Etudes et Techniques, 26 boulevard Victor, F-75996 Paris Armées, FranceThe work of this author was supported by Konrad-Zuse-Zentrum für Informationstechnik Berlin, Federal Republic of Germany  相似文献   

18.
BOOK REVIEWS     
Book reviewed in this article: Atoms in Action, by George Russell Harrison Earth's Adventures, by Carroll Lane Fenton Hackh's Chemical Dictionary, Third Edition, revised and edited by Julius Grant Physics of the 20th Century, by Pascual Jordan. Translated by Eleanor Oshry. Our Air-Ace Would, by Leonard O. Packard, Head of the Department of Geography, Teachers College, of the City of Boston, Bruce Overton, formerly of the Male High School, Louisville, Kentucky, and Ben Wood Columbia College, Columbia University. Organic Chemistry for the Laboratory, by C. W. Porter and T. D. Stewart Vital Mathematics, by Edwin Brown Allen, Head of The Department of Mathematics, Rensselaer Polytechnic Institute, Troy, N. Y., Dis Maly, Instructor in Mathematics, Rensselaer Polytechnic Institute, and S. Herbert Starkey, Jr., Head of Mathematics Department, Madison High School, Madison, N. J. Plane and Spherical Trigonometry, by William C. Brenke, University of Nebraska. Spherical Trigonometry With Tables, by Donald H. Ballou, Ph.D. Assistant Professor of Mathematics, Middlebury College, and Frederick H. Steen, Associate Professor of Mathematics, Allegheny College. Riddles in Mathematics, A Book of Paradoxes, by Eugene P. Northrop. Mathematics For Mariners, by Chester E. Dimick, Captain USGG; and Cuthbert C. Hurd, Lieutenant, USCGR Basic Mathematics, by Paul H. Daus, Professor of Mathematics, University of California, Los Angeles; John M. Gleason, Assistant Professor of Mathematics, San Diego State College, San Diego; and William M. Whyburn, Professor of Mathematics and Educational Supervisor, ESMWT, University of California, Los Angeles. Biology and Man, by Benjamin C. Gruenberg, Consultant of Social Security; Formerly Chairman, Biology Departments, Commercial and Julia Richman High Schools, New York City; and N. Eldred Bingham, Horace Mann-Lincoln School Elements of Biology, by Perry D. Strausbaugh, Professor of Botany, West Virginia University and Bernal R. Weimer.  相似文献   

19.
In this paper, we give a barrier argument at infinity for solutions of an elliptic equation on a complete Riemannian manifold. By using the barrier argument, we can construct a nonnegative (bounded, respectively) solution of the elliptic equation, which takes the given data at infinity of each end. In particular, we prove that if a complete Riemannian manifold has finitely many ends, each of which is Harnack and nonparabolic, then the set of bounded solutions of the elliptic equation is finite dimensional, in some sense. We also prove that if a complete Riemannian manifold is roughly isometric to a complete Riemannian manifold satisfying the volume doubling condition, the Poincaré inequality and the finite covering condition on each end, then there exists a nonnegative solution of an elliptic equation taking the given data at infinity of each end of the manifold. These results generalize those of Yau, of Donnelly, of Grigor'yan, of Li and Tam, of Holopainen, and of the present authors, but with the barrier argument at infinity that enables one to overcome the obstacle due to the nonlinearity of solutions. Received: 11 November 1999  相似文献   

20.
令K_4(i,j,k,l,m,n)表示两两三度点间的路长分别为i,j,k,l,m,n的K_4-同胚图.对6条路的长均大于1且有4条路的长相等其余两条路互不相等的K_4-同胚图的着色进行了研究,得到了一类色唯一的K_4-同胚图.  相似文献   

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