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901.
Akpofure E. Taigbenu 《Numerical Methods for Partial Differential Equations》2010,26(6):1300-1315
This article presents the derivation and implementation of the normal directional flux compatibility equation (relationship) at internal nodes when the Green element formulation that consistently provides accurate estimates of the primary variable, and its normal directional derivative (normal flux) is applied in 2D heterogeneous media to steady and transient potential problems. Such a relationship is required to resolve the closure problem due to having fewer integral equations than the number of unknowns at internal nodes. The derivation of the relationship is based on Stokes' theorem, which transforms the contour integral of the normal directional fluxes into a surface integral that is identically zero. The numerical discretization of the compatibility equation is demonstrated with four numerical examples using the six‐node quadratic triangular and the four and eight‐node rectangular elements. The incorporation of triangular elements into the current formulation demonstrates that the internal compatibility equation can be successfully implemented on irregular grids. The direct calculation of the fluxes significantly enhances the accuracy of the formulation, so that high accuracy, exceeding that of the finite element method, is achieved with very coarse spatial discretization. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010 相似文献
902.
Samah Ben Atia Anis Messaoud Ridha Ben Abdennour 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2018,24(1):26-43
In this paper, an online algorithm is proposed for the identification of unknown time-varying input delay in the case of discrete non-linear systems described by decoupled multimodel. This method relies on the minimization of a performance index based on the error between the real system and the partial internal models outputs. In addition, a decoupled internal multimodel control is proposed for the compensation of discrete non-linear systems with time-varying delay. This control scheme incorporates partial internal model controls. Each partial controller is associated to a specified operating zone of the non-linear system. The switching between these controllers is ensured by a supervisor that contains a set of local predictors. A simulation example is carried out to illustrate the significance of the proposed time-varying delay identification algorithm and the proposed internal multimodel control scheme. 相似文献
903.
This paper presents the investigation of tuning the color and photoluminescence of a range of triphenylamine‐ based derivatives with various substituent groups. The ultraviolet/visible absorption and fluorescence spectroscopy of the derivatives showed remarkable difference. The molecular geometry optimization demonstrated that the properties of the ground state and the excited state of the compounds have a close relationship with the substituent groups. Therefore, it is possible to tune the color and photoluminescence of the derivatives at molecular level. The cyclic voltammograms of these compounds were detected in methylene chloride at various scan rates. The thermal stabilities of the compounds were analyzed with the different scanning calorimetry and the thermogravimetry. 相似文献
904.
D Narasimha 《Pramana》1999,53(6):1039-1042
Spiral galaxies at moderate redshifts and oriented optimally could form characteristic multiple images of extended background
sources from which the mass distribution in the galaxy can be estimated. The absorption profile due to the galaxy provides
a reliable tool for the chemical and thermal diagnostic of the lens. 相似文献
905.
T. Pöschel T. Schwager N.V. Brilliantov 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,10(1):169-174
The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction
coefficient reveals strongly non-linear dependence on the cylinder's velocity. For low velocity the rolling-friction coefficient
rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity
according to decreasing contact area and deformation of the surface.
Received 24 December 1998 and Received in final form 14 January 1999 相似文献
906.
R. Arnold C. Augier J. Baker A. Barabash D. Blum V. Brudanin A.J. Caffrey J.E. Campagne E. Caurier D. Dassié V. Egorov T. Filipova R. Gurriaran J.L. Guyonnet F. Hubert Ph. Hubert S. Jullian O. Kochetov I. Kisel V.N. Kornoukhov V. Kovalenko D. Lalanne F. Laplanche F. Leccia I. Linck C. Longuemare Ch. Marquet F. Mauger H.W. Nicholson I. Pilugin F. Piquemal J-L. Reyss X. Sarazin F. Scheibling J. Suhonen C.S. Sutton G. Szklarz V. Timkin R. Torres V.I. Tretyak V. Umatov I. Vanyushin A. Vareille Yu. Vasilyev Ts. Vylov 《The European Physical Journal A - Hadrons and Nuclei》1999,6(3):361-366
The Pauli Exclusion Principle (PEP) was tested with the NEMO-2 detector. Limits at the 90% C.L. on the violation of PEP for
p-shell nucleons in 12C were obtained. Specifically, transitions to the fully occupied 1s
1/2-shell yielded a limit of 4.2 · 1024 y for the process with emission of a γ-quantum. Similarly limits of 3.1 · 1024 y for β− and 2.6 · 1024 y for β+ Pauli-forbidden transitions of 12C →12?12B) are reported here.
Received: 25 August 1999 相似文献
907.
This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric perturbation theory combined with elliptic regularity and Agmon-Combes-Thomas uniform exponential decay estimates. 相似文献
908.
909.
910.
The higher internal perfluoroak-2-enes react with ammonium hydroxide at atmospheric pressure to give the corresponding iminoenamines,
whose further transformations yield heptafluoroacetylacetone analogs.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1710–1712, September, 1999. 相似文献