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M. Jankov G. Løvoll H. A. Knudsen K. J. Måløy R. Planet R. Toussaint E. G. Flekkøy 《Transport in Porous Media》2010,84(3):569-585
The effects of seismic stimulation on the flow of two immiscible fluids in an elastic synthetic porous medium is experimentally
investigated. A wetting fluid is slowly evacuated from the medium, while a pressure oscillation is applied on the injected
non- wetting fluid. The amplitude and frequency of the pressure oscillations as well as the evacuation speed are kept constant
throughout an experiment. The resulting morphology of the invading structure is found to be strongly dependent on the interplay
between the amplitude and the frequency of the applied pressure oscillations and the elasticity of the porous medium. Different
combinations of these properties yield morphologically similar structures, allowing a classification of structures that is
found to depend on a proposed dimensionless number. 相似文献
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A general configuration interaction (CI) algorithm incorporating one- and two-electron spin-orbit operators is presented.
The algorithm is determinant based and enables the use of highly vectorized non-relativistic algorithms in the most operation-intensive
part. Excitations between α and β spin orbitals are avoided in the time consuming parts by performing separate S
+ and S
− operations. The relativistic CI expansions are often very large, so the algorithms require only the presence of segments
of vectors in memory. Double-group symmetry is fully accounted for and time-reversal symmetry is exploited for both even and
odd numbers of electrons.
Received: 12 October 1996 / Accepted: 24 January 1997 相似文献
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G. L voll B. Sandnes Y. M heust K.J. M l y J.O. Fossum G.J. da Silva M.S.P. Mundim R. Droppa Jr. D.M. Fonseca 《Physica B: Condensed Matter》2005,370(1-4):90-98
We performed synchrotron X-ray scattering studies of the dynamics of the water intercalation front in a Na–Fluorohectorite clay. Like other smectite clays, fluorohectorite particles can swell due to intercalation of successive water layers. Monitoring the intensities of Bragg peaks of the known 1- and 2-water-layer hydration states at different positions in the sample enabled spatial and temporal measurement of the proportions of the different hydration states. From experiments with controlled temperature and an imposed humidity gradient on a quasi one-dimensional powder sample, we were able to localize the intercalation front and demonstrate that the width of this front was smaller than 2 mm after penetrating 9 mm into the sample. The speed at which the intercalation front advanced through the sample during the diffusion process was shown to decrease with time. The diffraction signature of random water intercalation in the vicinity of the intercalation front also provided information on the changes in the water content of the mesopores around clay particles. 相似文献
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Olav Aursj? Grunde L?voll Henning Arendt Knudsen Eirik G. Flekk?y Knut J?rgen M?l?y 《Transport in Porous Media》2011,86(1):125-134
We present here a direct comparison between a slow quasi-two-dimensional pore scale drainage experiment and a two-component 2D lattice Boltzmann simulation. An experimental setup consisting of approximately 10 × 10 pores is mapped onto the 2D lattice Boltzmann model with the aspiration of reproducing the behavior and dynamics of a slow drainage process on a pore scale. 相似文献
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Merethe Sjvoll Hilde Fagerli Odd Gropen Jan Almlf Jeppe Olsen Trygve U. Helgaker 《International journal of quantum chemistry》1998,68(1):53-64
The low-lying electronic states of PtH were studied by all-electron one- and two-component variational calculations on the multireference CI levels. The orbital optimization is performed within a one-component formalism, whereas the further refinement of the wave functions follows two different schemes: The most demanding approach introduces spin–orbit coupling in the CI optimization step, giving a simultaneous treatment of electron correlation and spin–orbit coupling. The second, considerably less demanding approach, corresponds almost to a perturbational treatment, introducing spin–orbit coupling as a final step after the CI optimization by diagonalizing the resulting Hamiltonian matrix over CI states. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 68: 53–64, 1998 相似文献
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Merethe Sjøvoll Hilde Fagerli Odd Gropen Jan Almlöf Bernd Schimmelpfennig Ulf Wahlgren 《Theoretical chemistry accounts》1998,99(1):1-7
Relativistic two-electron operators obtained by the Douglas-Kroll transformation contain p-dependent kinematic prefactors
which are not present in the corresponding Breit-Pauli operators. These factors are usually calculated using a resolution
of the identity approach, which requires integral transformations. In the present article we describe an alternative approach,
based on a local approximation, where the effect of the prefactors can be absorbed in the atomic contraction coefficients.
The effect of the local approximation is investigated in detail. The suggested approach is simple to implement in integral
codes that allow the use of a general contraction scheme.
Received: 27 June 1997 / Accepted: 1 October 1997 相似文献
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O. Gropen M. Sjøvoll H. Strømsnes E. Karlsen O. Swang K. Fægri Jr 《Theoretical chemistry accounts》1994,87(4-5):373-385
Summary Relativistic effective core potential calculations have been carried out for the reactions of Pt, Os, Ir, and Re with H2. The calculations demonstrate the importance of a singly occupied 6s orbital for forming a strong bond. Pt and Ir have low-lying states with such occupancy, whereas Os and Re only attains this through a rather costly excitation. In consequence, the reaction barriers are considerably smaller for Pt and Ir than for Os and Re. 相似文献
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G. Løvoll M. Jankov K. J. Måløy R. Toussaint J. Schmittbuhl G. Schäfer Y. Méheust 《Transport in Porous Media》2011,86(1):305-324
We report on results from primary drainage experiments on quasi-two-dimensional porous models. The models are transparent,
allowing the displacement process and structure to be monitored in space and time during primary drainage experiments carried
out at various speeds. By combining detailed information on the displacement structure with global measurements of pressure,
saturation and the capillary number Ca, we obtain a scaling relation relating pressure, saturation, system size and capillary
number. This scaling relation allows pressure–saturation curves for a wide range of capillary numbers to be collapsed on the
same master curve. We also show that in the case of primary drainage, the dynamic effect in the capillary pressure–saturation
relationship observed on partially water saturated soil samples might be explained by the combined effect of capillary pressure
along the invasion front of the gaseous phase, and pressure changes caused by viscous effects in the wetting fluid phase. 相似文献
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