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991.
Gaelle Derrien Monique Tillard Laure Monconduit Claude Belin 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):e232-e232
KBa4Bi3O crystallizes in the centrosymmetric tetragonal space group I4/mcm. In this compound, bismuth is present as two anionic species, i.e. Bi24? dumbbells [Bi—Bi 3.113 (3) Å] and isolated Bi3?. Atom Bi1 (Bi3?) lies inside a bicapped square antiprism (2 × K and 8 × Ba). Atom Bi2, which forms the Bi24? dumbbell, sits inside a bicapped distorted trigonal prism (2 × K and 6 × Ba). O atoms occupy tetrahedral voids between Ba atoms. 相似文献
992.
Andres Weintraub Richard L. Church Alan T. Murray Monique Guignard 《Annals of Operations Research》2000,96(1-4):271-285
Linear Programming and Mixed Integer Linear Programs have been used for forest planning since the 60's to support decision
making on forest harvesting and management. In particular, during the last two decades of forest management there has been
an increased interest in spatial issues. Further, new environmental concerns, such as resource sustainability and wildlife
protection, impose that increased attention be paid to activities carried out on the ground. Road building needed for access
also requires spatial definiton. As a result, more complex models must be used. We discuss the issues which have led to the
combinatorial nature of some main forest management problems and the solution algorithms that have been proposed for these
problems, including local search heuristics, random search approaches, strengthening of mixed integer model formulations and
Lagrangian relaxation. In this survey, we discuss which of the proposed approaches have been used succesfully, the advantages
and shortcomings of each and what are still open research problems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
993.
Monique A. Mballa Mballa Ulrich S. Schubert Johan P. A. Heuts Alex M. van Herk 《Journal of polymer science. Part A, Polymer chemistry》2011,49(2):314-326
This article describes a method for carrying out emulsion copolymerization using an automated synthesizer. For this purpose, batch emulsion copolymerizations of styrene and butyl acrylate were investigated. The optimization of the polymerization system required tuning the liquid transfer method, sufficient oxygen removal from the reaction medium and setting a proper sampling procedure. The monomer conversion‐time plots obtained with gas chromatography revealed a good reproducibility of the automated reaction kinetics. Furthermore, the particle size distributions and the properties of the final products were found to be highly reproducible. The performance of the automated reactions was subsequently compared with the conventional ones: similar reproducibility of either synthetic method was observed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
994.
Priv.-Doz. Dr.-Ing. R. Harbord Dipl.-Ing. H. J. Becker 《Archive of Applied Mechanics (Ingenieur Archiv)》1981,50(4):237-252
Übersicht Bei stählernen Behältern treten in Bereichen mit polygonartig veränderlicher Schalenform, verstärkten Ausschnitten oder konstruktiven Verzweigungen Spannungsspitzen auf, die sich durch örtliches Fließen abbauen. Um diesen Vorgang für rotationssymetrische Geometrien rechnerisch verfolgen zu können, wurden elastisch-plastische Ringelemente entwickelt und deren Brauchbarkeit an Hand von Vergleichsbeispielen erprobt.
Diese Arbeit wurde aus Mitteln der Stiftung Volkswagenwerk und der Deutschen Forschungsgemeinschaft gefördert 相似文献
Summary Elasticplastic shell elements for axi-symmetric problems are developed, which enable the calculation of thin and thick vessel structures including those with varying geometry, holes and junctions. Comparisons of the present analysis with known solutions demonstrate the efficiency of the present elements.
Diese Arbeit wurde aus Mitteln der Stiftung Volkswagenwerk und der Deutschen Forschungsgemeinschaft gefördert 相似文献
995.
In this work, crack initiation in adhesive lap joints of arbitrary joint configuration is studied by means of a finite fracture mechanics approach. The analysis is based on a general stress solution for adhesive joints combined with a coupled stress and energy criterion. The instantaneous formation of a crack of finite size is predicted if a stress and energy criterion are satisfied simultaneously. The closed-form analytical solution of the stress field allows for an efficient evaluation of the crack initiation load and corresponding finite crack length. A comparison to experimental results from literature and to numerical results obtained with a cohesive zone model approach shows a good agreement. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
996.
In this work, stress singularities in isotropic bi-material junctions are investigated using Reissner-Mindlin plate theory by means of a complex potential formalism. The governing system of partial differential equations is solved employing methods of asymptotic analysis. The resulting asymptotic near-fields including the singularity exponent λ are obtained in a closed-form analytical manner as solutions of a corresponding eigenvalue problem. The singular solution character is discussed for different geometrical configurations. In particular, the present study investigates the influence of the material constants on the singularity exponent. It is shown, that the Reissner-Mindlin theory allows for distinguishing between singularities of the bending moments and the transverse shear forces. Further, stronger singularities than the classical crack-tip singularity are observed. The results allow for further application such as a combination with numerical methods. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
997.
998.
Monique Sablé-Tougeron 《Archive for Rational Mechanics and Analysis》1988,101(3):261-292
Sans résumé
Présenté par H. Brézis 相似文献
999.
Dr. Ing. W. Becker 《Archive of Applied Mechanics (Ingenieur Archiv)》1994,65(1):38-43
Summary For a symmetric [±]s-angle-ply laminate coupon within the framework of linear elasticity the free-edge effect is treated in a closed-form analytical way. To that end, for uniaxial tension the near-edge deformation is traced back to a complex-analytical potential. For the given boundary conditions the respective potential is determined and thus the resultant displacement field and the accompanying stresses. Thereby, in particular, a logarithmic singularity is obtained for the free-edge stress concentration. 相似文献
1000.
S. Loose H. Richard J. Bosbach M. Thimm W. Becker M. Raffel 《Experiments in fluids》2006,40(4):643-653
This article reports on experimental aerodynamic investigations on a generic high-speed train configuration performed within two different wind tunnels. Both wind tunnels are specialized facilities for high Reynolds number investigations and offer low turbulence levels. The wind tunnels are the cryogenic wind tunnel located in Cologne (KKK) and in the high-pressure wind tunnel located in Göttingen (HDG). Both facilities are part of the German–Dutch wind tunnel association (DNW). The adaptation and application of three optical measurement techniques for such high Reynolds number investigations is described in the article. The optical methods are: Particle Image Velocimetry for the measurement of velocity fields, Background Oriented Schlieren technique for density gradient measurements, and a white light Digital Speckle Photography technique for model deformation monitoring. 相似文献