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101.
102.
D. V. van Coevorden M. H. Ernst R. Brito J. A. Somers 《Journal of statistical physics》1994,74(5-6):1085-1115
FCHC lattice gases are the basic models for studying flow problems in three-dimensional systems. This paper presents a self-contained theoretical analysis and some computer simulations of such lattice gases, extended to include an arbitrary number of rest particles, with special emphasis on non-semi-detailed balance (NSDB) models. The special FCHC lattice symmetry guarantees isotropy of the Navier-Stokes equations, and enumerates the 12 spurious conservation laws (staggered momenta). The kinetic theory is based on the mean field approximation or the nonlinear Boltzmann equation. It is shown how calculation of the eigenvalues of the linearized Boltzmann equation offers a simple alternative to the Chapman-Enskog method or the multi-time-scale methods for calculating transport coefficients and relaxation rates. The simulated values for the speed of sound in NSDB models slightly disagree with the Boltzmann prediction. 相似文献
103.
Héctor Rosas Leidy Erika Sarmiento Vito Lubes María Goncalves Mary Lorena Araujo Felipe Brito 《Journal of solution chemistry》2008,37(5):701-711
The complex species formed between vanadium(III) cysteine and small blood serum bioligands: lactic, oxalic, citric and phosphoric
acids were studied in aqueous solution by means of electromotive force measurements, Emf(H), at 25 °C and 3.0 mol⋅dm−3 KCl as the ionic medium. The ternary complexes were studied by potentiometric measurements and the data analyzed using the
least-squares computational program LETAGROP to obtain the respective stability constants and stoichiometric coefficients.
The UV-Vis spectrophotometric measurements were done in order to make a qualitative characterization of the complexes formed
in aqueous solution. 相似文献
104.
A. Montero Alvarez J. R. Estévez Alvarez H. Iglesias Brito O. Pérez Arriba D. López Sánchez H. T. Wolterbeek 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(1):63-67
Summary An epiphytic lichen (Physcia alba sp.) grown over Roystonea regia tree was used as biomonitor of air quality in the Havana City west side. During the survey, 81 sampling sites were selected
according to traffic and industry conditions. The concentration for 14 elements (Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn,
Sr, Cd and Pb) was determined by flame atomic absorption spectrometry (FAAS) and anodic stripping voltammetry (ASV). Contents
of Cu, Zn, Cd and Pb obtained by both techniques were compared. Several biological reference materials (RM's) were analyzed
in order to assure the quality of analytical results. Some pollution sources were identified using principal component analysis.
A total of 5 factors were achieved, of which 4 could be interpreted in terms of anthropogenic pollution sources. However,
the expected correlation between traffic influence and lead concentration in lichen could not be demonstrated. The factor
values patterns are presented. 相似文献
105.
Humberto César Chaves Fernandes Davi Bibiano Brito 《International Journal of Infrared and Millimeter Waves》2007,28(8):651-661
Photonic band gap (PBG) crystals have been used as a perfectly reflecting substrate for many millimeter wave applications.
In this work the fin line directional coupler with substrate PBG was analyzed using the TTL - Transverse Transmission Line
- method. Compared to other full wave methods the TTL is an efficient tool to determine the coupler characteristics, making
possible a significant algebraic simplification of the equations involved in the process. In order to analyze this structure
the effective dielectric constant, the attenuation constant and the coupling were determined. The results obtained for this
application and the conclusions are presented.
This work was partially financed by CNPQ. 相似文献
106.
We study the disordered, multispiral solutions of two-dimensional oscillatory media for parameter values at which the single-spiral/vortex solution is fully stable. Using the complex Ginzburg-Landau (CGLE) equation, we show that these states, heretofore believed to be static, actually evolve extremely slowly. This is achieved via a reduction of the CGLE to the evolution of the sole vortex coordinates. This true defect-mediated turbulence occurs in two distinct phases, a vortex liquid characterized by normal diffusion of spirals, and a slowly relaxing, intermittent, "vortex glass." 相似文献
107.
Transport effects in a monolayer consisting of a binary granular mixture, confined in a horizontally vibrating circular dish, are studied experimentally and compared with a reduced theoretical model. Depending on the ratio of the particles' material density and size, migration of the larger particles occurs either towards the boundary or to the center of the circular container. These directed motions show similarities to the Brazil-nut effect and its reverse form. 相似文献
108.
We present a way of tiling the plane with a regular hexagonal network of defects. The network is stable and follows in consequence of the three-junctions that appear in a model of two real scalar fields that presents Z3 symmetry. The Z3 symmetry is effective in both the vacuum and defect sectors, and no supersymmetry is required to build the network. 相似文献
109.
A. Alves L. Brito M.H. Caldeira J.M. Domingos P. Martins H. Pascoal J. Da Providência M.C. Ruivo E.M. Silva C.A. De Sousa J. Urbano 《Nuclear Physics A》1977,284(3):420-424
A simple criterion for the approximate validity of the single projection Peierls-Yoccoz method is discussed. A procedure for chosing the generator coordinate is proposed. 相似文献
110.
Feifel R Gel'mukhanov F Baev A Agren H Piancastelli MN Bässler M Miron C Sorensen SL Naves De Brito A Björneholm O Karlsson L Svensson S 《Physical review letters》2002,89(10):103002
An interference quenching of the nu(")=1 vibrational line in the resonant Auger decay of N 1s-->pi(*) core-excited N2 is observed and analyzed. The intensity ratio between the nu(")=1 and nu(")=0 vibrational levels of the X2Sigma(+)(g) final state shows a surprising nonmonotonous variation as a function of frequency detuning, going through a minimum with a complete suppression of nu(")=1. We have developed a simple model which shows a linear relation between the value of the detuning frequency for this minimum and the equilibrium bond distance R(0)(c) of the core-excited state. A new way is thus established of determining the equilibrium bond distance for the core-excited state with a precision deltaR(0)(c)<10(-3) A. 相似文献