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111.
The sloshing problem is considered in a half-space covered by a rigid dock with apertures. The dependence of the fundamental sloshing frequency on the shape of the free surface region is studied. It is proved that the inequality holds between the fundamental eigenvalues corresponding to two different regions if some conditions are fulfilled. These conditions are verified for particular classes of regions of a fixed area in order to demonstrate that the disk yields the maximum of the fundamental eigenvalue for each of these classes. On the other hand, examples of regions are constructed for which the fundamental eigenfrequency is larger than that for the circular aperture of the same area and even as large as one wishes. To cite this article: V. Kozlov, N. Kuznetsov, C. R. Mecanique 330 (2002) 723–728. 相似文献
112.
Nearly repetitive structures can present at least two kinds of vibration modes: localized modes and modulated ones. In this Note, the multiple scale method is applied to characterize a packet of modulated modes. In this respect, only small size problems are to be solved: periodic problems posed on a few basic cells and amplitude equations, which define a sort of homogenized model for this type of modes. It is established that the influence of the non-repetitive part of the structure is accounted by a boundary condition. To cite this article: E.M. Daya et al., C. R. Mecanique 331 (2003). 相似文献
113.
El Mostafa Daya Bouazza Braikat Noureddine Damil Michel Potier-Ferry 《Comptes Rendus Mecanique》2002,330(5):333-338
By homogenization theory, one can predict the vibrations of long repetitive structures in the low frequency range. Beyond this range, many modes have a modulated shape. Based on a multiple scale analysis, a continuum model is presented, that is able to account for this class of modes. This model involves a real coefficient that can be computed from the finite element resolution of problems defined on a few basic cells. An application in 2D elasticity is presented. To cite this article: E.M. Daya et al., C. R. Mecanique 330 (2002) 333–338. 相似文献
114.
115.
Let T be an extension of a one to one normal operator A by a nilpotent operator N. In this paper we calculate the defect of reflexivity of T. We give a necessary and sufficient condition to insure the reflexivity of such extensions. In particular, it is shown that T is reflexive when N is reflexive. 相似文献
116.
Peter Heering 《Physics in Perspective (PIP)》2006,8(1):52-63
I discuss our replication of the wire-torsion experiments that Charles Augustin Coulomb (1736–1806) reported in a session
of the Paris Académie des Sciences in 1784. I first explain the nature and purpose of the replication method and then apply it to an analysis of Coulomb’s experiments.
I conclude by placing Coulomb’s presentation of his memoir into its specific historical contest. 相似文献
117.
Alexandre Delye de Clauzade de Mazieux Michel Marot Monique Becker 《Comptes Rendus Mecanique》2006,334(11):669-673
d-dominating sets in graphs are very important in system and network engineering. Their constructions is thus an important research topic. An heuristic which forms such sets by using a given criterion is proposed. We simplify the heuristic presented elsewhere. We extend it and prove the correctness of the extended heuristic. This heuristic has the advantage of being distributed and scalable. To cite this article: A. Delye de Clauzade de Mazieux et al., C. R. Mecanique 334 (2006). 相似文献
118.
获得了广义 Liénard系统dxdt=p(y) -F(x) , dydt=-g(x) q(y)所有正半轨线有界的若干充分条件 ,推广改进了已有文献 [1— 1 2 ]中的相应结果 . 相似文献
119.
A series of High-Cycle Fatigue (HCF) criteria for polycrystalline materials is based on a multiscale interpretation, proposed initially by Dang Van, in which the principal concepts are a two scales model and a shakedown condition. The purpose of this Note is to extend the study of the different dissipative regimes during cyclic loading within this framework by using a self consistent homogenization scheme in coupled thermoplasticity. It is shown that the Sachs and Lin-Taylor schemes are not able to represent the thermal evolutions observed during fatigue tests. To cite this article: E. Charkaluk, A. Constantinescu, C. R. Mecanique 334 (2006). 相似文献
120.
W. van der Eijk 《Fresenius' Journal of Analytical Chemistry》1979,297(1):10-12
Summary In 1973 a research programme Community Bureau of Reference — BCR has been started in the Commission of the European Communities. Its task is to group, harmonize, dovetail and supplement national efforts in the field of reference materials and methods. Its terms of reference and working methods are explained. As a result of the BCR activities so far 26 CRMs are produced, covering several sectors of technical and scientific activities (e.g. ferrous and non-ferrous metallurgy, organic chemistry and clinical laboratory sciences). Organization of the measurement campaigns and the procedures for certification are outlined.
Die Aktivitäten des Europäischen Referenzbüros der Gemeinschaft — BCR
Zusammenfassung Im Jahre 1973 wurde von der Kommission der Europäischen Gemeinschaften ein Forschungsprogramm über Referenzmaterialien aufgestellt, das seinen Ausdruck im Europäischen Referenzbüro der Gemeinschaft (BCR) fand. Seine Aufgabe ist es, die nationalen Bemühungen auf diesem Gebiet zu stärken, zu harmonisieren und zu ergänzen. Zur Zeit sind 26 verschiedene Referenzmaterialien verfügbar, die mehrere technisch-wissenschaftliche Gebiete umfassen (Eisen- und Nichteisen-Metallurgie, organische Chemie, klinische Analyse). Organisation, Arbeitsprogramm und Zertifizierungsverfahren des Büros werden beschrieben.
Presented at Euroanalysis III conference, Dublin, August 20–25, 1978 相似文献