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51.
Maderna A Huertas R Hawthorne MF Luguya R Vicente MG 《Chemical communications (Cambridge, England)》2002,(16):1784-1785
A boron-rich, water-soluble porphyrin conjugate was synthesized by coupling of two carboranyl alcohols with 2-chlorophenoxyphosphorus dichloride, followed by conjugation to an amine-functionalized tetraphenyl-porphyrin via an amide linkage. 相似文献
52.
Escuer A Vicente R Mautner FA Goher MA Abu-Youssef MA 《Chemical communications (Cambridge, England)》2002,(1):64-65
Novel 3D topologies combining diazine and azido bridges between MnII magnetic centres have been obtained and characterised by low-temperature magnetic measurements. 相似文献
53.
[reaction: see text] An unprecedented endo-selective and regioselective intermolecular Pauson-Khand reaction takes place when heterobimetallic (Mo-Co) complexes derived from N-(2-alkynoyl)oxazolidinones or sultams are heated in the presence of norbornadiene. 相似文献
54.
A generalised Hohenberg–Kohn theorem is described in terms of the sign of the secondorder energy variation. Independently, it is also corroborated within the perturbation theoretical framework. An alternative formulation of the Hohenberg–Kohn theorem, based on the relationships involving the matrix representations of density functions and the Hamiltonian operator variations, is shown to extend the validity of the theorem to the excited states of the Hamiltonian operators possessing nondegenerate spectra. Finally, a connection with Brillouin's theorem when energy variation becomes stationary is also outlined. 相似文献
55.
E.?DintwaEmail author M.?van?Zeebroeck E.?Tijskens H.?Ramon 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,39(1):77-85
The theory of elastic contact between two spherical bodies according to Hertz, Mindlin and others is used as a basis for an extension to include the contribution of the viscous effects to the total stress for viscoelastic spheres subjected to twisting moments. Expressions relating twisting moment to the radius of a stick region of the contact surface and the radius of the stick region to twist angle are derived. Two term power series truncations of the relations are then used to derive approximate expressions for torsional stiffness of the bodies. Validation of the model was by experiments utilising a rheometer device. Applications for the model in post-harvest agriculture include extraction of material surface properties for use in discrete element modelling of mechanical interactions of fruits and other spheroidal produce during machine handling.Received: 6 January 2004, Published online: 18 June 2004PACS:
46.35. + z Viscoelasticity, plasticity, viscoplasticity - 46.55. + d Tribology and mechanical contacts - 62.20.Dc Elasticity, elastic constants 相似文献
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Every compact symmetric bilinear form B on a complex Hilbert space produces, via an antilinear representing operator, a real spectrum consisting of a sequence decreasing to zero. We show that the most natural analog of Courant's minimax principle for B detects only the evenly indexed eigenvalues in this spectrum. We explain this phenomenon, analyze the extremal objects, and apply this general framework to the Friedrichs operator of a planar domain and to Toeplitz operators and their compressions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
59.
Oscar García Josep Vehí Jose Campos e Matos António Abel Henriques Joan Ramon Casas 《Journal of Computational and Applied Mathematics》2008
An efficient health monitoring system for damage detection in civil engineering structures using on-line monitoring data is being developed to identify any possible damage in short time. The present work is based on the treatment of uncertainties, which is one of the basic common difficulties faced when modelling structures. A methodology, based on interval analysis (IA) theory [R.E. Moore, Interval Analysis, Prentice-Hall, Englewood Cliffs, NJ, 1966] applied to a numerical constraint satisfaction problem (CSP) [J.R. Casas, J.C. Matos, J.A. Figueiras, J. Vehí, O. García, P. Herrero, Bridge monitoring and assessment under uncertainty via interval analysis, in: Ninth International Conference On Structural Safety And Reliability—ICOSSAR2005, 2005. pp. 487–494], is implemented in the damage detection [J.R. Casas, J.C. Matos, J.A. Figueiras, J. Vehí, O. García, P. Herrero, Bridge monitoring and assessment under uncertainty via interval analysis, in: Ninth International Conference On Structural Safety And Reliability—ICOSSAR2005, 2005. pp. 487–494] and modelling system of a long-term monitoring project in order to achieve such an objective. An algorithm is being developed for using such methodology with the obtained data. 相似文献
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