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1.
We propose a three-field formulation for efficiently solving a two-dimensional Stokes problem in the case of nonstandard boundary conditions. More specifically, we consider the case where the pressure and either normal or tangential components of the velocity are prescribed at some given parts of the boundary. The proposed computational methodology consists in reformulating the considered boundary value problem via a mixed-type formulation where the pressure and the vorticity are the principal unknowns while the velocity is the Lagrange multiplier. The obtained formulation is then discretized and a convergence analysis is performed. A priori error estimates are established, and some numerical results are presented to highlight the perfomance of the proposed computational methodology.
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E. Matsinos J. Guy E. Simopoulou W. Venus P. Allport M. Berggren M. Calicchio T. Coghen A. M. Cooper-Sarkar O. Erriquez N. Giannakopoulos G. T. Jones P. Marage M. M. Mobayyen D. R. O. Morrison S. O'Neale M. A. Parker J. Sacton R. A. Sansum N. Schmitz G. W. Van Apeldoorn K. Varvell A. Vayaki H. Wachsmuth W. Wittek BEBC WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,44(1):79-87
Backward proton and pion production is studied in ν and \(\bar v\) charged current interactions in neon. The results are compared with other experiments and theory. The complete backward proton data is compatible with protons produced by reinteractions in the nucleus. However in events with only one proton, muon variables appear correlated to those for the backward proton, as expected by the two-nucleon correlation model. 相似文献
4.
R. Cabrera‐Trujillo J. R. Sabin Y.
hrn E. Deumens 《International journal of quantum chemistry》2003,94(4):215-221
Under certain collision conditions, a swift ion projectile colliding with a target will gain rather than lose kinetic energy, contrary to the standard conception of stopping power. In this work, we consider the conditions for such a collision such that the energy loss is negative, that is, that there will be projectile kinetic energy gain. In particular, for a target initially in the ground state we find that the projectile gains kinetic energy only when charge exchange and de‐excitation processes are involved. This occurs when the electron affinity of the projectile is larger than the ionization potential of the target. Consequences of this effect are analyzed. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 215–221, 2003 相似文献
5.
P. Marage M. Aderholz P. Allport N. Armenise J. P. Baton M. Berggren D. Bertrand V. Brisson F. W. Bullock W. Burkot M. Calicchio E. F. Clayton T. Coghen A. M. Cooper-Sarkar O. Erriquez P. J. Fitch G. Gerbier J. Guy F. Hamisi P. O. Hulth G. T. Jones P. Kasper H. Klein R. P. Middleton D. B. Miller M. M. Mobayyen D. R. O. Morrison S. Natali M. Neveu S. W. O'Neale M. A. Parker P. Petiau J. Sacton R. A. Sansum E. Simopoulou C. Vallée K. Varvell A. Vayaki W. Venus H. Wachsmuth J. Wells W. Wittek BEBC WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,31(2):191-197
The cross section for coherent production of a single π? meson in charged current antineutrino interactions on neon nuclei has been measured in BEBC to be (175±25) 10?40 cm2/neon nucleus, averaged over the energy spectrum of the antineutrino wide band beam at the CERN SPS; this corresponds to (0.9±0.1) % of the total charged current \(\bar v_\mu \) cross section. The distributions of kinematical variables are in agreement with theoretical predictions based on the PCAC hypothesis and the meson dominance model; in particular, theQ 2 dependence is well described by a propagator containing a massm=(1.35±0.18) GeV. The absolute value of the cross section is also in agreement with the model. This analysis thus provides a test of the PCAC hypothesis in the antineutrino energy range 5–150 GeV. 相似文献
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The electron impact mass spectra of the 4-formyl-1, 3-dihydro-2H-imidazole-2-thione, its six 1-methyl(n-propyl, n-hexyl)-3-methyl(phenyl)-disubstptuted derivatives, and the 1,3-dihydro-1-phenyl-2H-imidazole-2-thiome are discussed. The fragmentation pattern is strongly influenced by the alkyl or phenyl N-substituents, as well as by the length of the alkyl chain. The odd-electron ions containing an N-phenyl substituent, but not a propyl or hexyl group, eject a hydrogen atom from the phenyl ring, while the presence of a long alkyl chain greatly enhances the loss of the sulphyhydryl radical and facilitates the expulsion of several alkenes, and alkyl and alkenyl radicals. 相似文献
9.
Jose G. Trujillo‐Ferrara Rosa Luisa Santilln‐Baca Norberto Farfn‐García Itzia I. Padilla‐Martínez Efrn V. García‐Bez 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(3):o125-o128
The molecular and supramolecular structures of 2‐(1,3‐dioxo‐2,3,3a,4,7,7a‐hexahydro‐1H‐isoindol‐2‐yl)phenyl acetate, C16‐H15NO4, (I), and its para isomer, 4‐(1,3‐dioxo‐2,3,3a,4,7,7a‐hexahydro‐1H‐isoindol‐2‐yl)phenyl acetate, (II), are reported. The torsion angle between the succinimide and benzene rings depends on the position of the acetoxy substitution [89.7 (1) and 61.9 (1)° for (I) and (II), respectively]. The twist of the acetoxy group relative to the mean plane of the benzene ring is almost independent of the acetoxy position [66.0 (1) and 70.0 (1)°]. Packing interactions for both compounds include soft C—H⋯X (X = O and Ph) interactions, forming chains of centrosymmetric dimers and interlinked chains for (I) and (II), respectively. In addition, three perpendicular dipole C=O⋯C=O interactions contribute to the supramolecular structure of (II). 相似文献
10.
Cristina Trujillo Goar Sánchez-Sanz Ibon Alkorta José Elguero 《Structural chemistry》2013,24(4):1145-1151
Theoretical calculations at the B3LYP/6-311++G(d,p) level have been carried out on the reaction path connecting a dipeptide to an imidazolinone as a model for the formation of GFP. In addition, we have studied the hydration effects on the processes, adding a water molecule to assist the cyclization. The solvent effects have been taken into account by introducing the monohydrated molecules into a solvent cavity with a polarized continuum model. Significant reductions of the energy barriers for the reaction path can be observed within the water-assisted processes. The solvent effects account for a barrier lowering of 4–5 kJ mol?1. 相似文献