30,015 research outputs found
Contact values of the radial distribution functions of additive hard-sphere mixtures in d dimensions: A new proposal
The contact values of the radial distribution functions
of a -dimensional mixture of (additive) hard spheres are considered. A
`universality' assumption is put forward, according to which
, where is a common function for all
the mixtures of the same dimensionality, regardless of the number of
components, is the packing fraction of the mixture, and is a
dimensionless parameter that depends on the size distribution and the diameters
of spheres and . For , this universality assumption holds for the
contact values of the Percus--Yevick approximation, the Scaled Particle Theory,
and, consequently, the Boublik--Grundke--Henderson--Lee--Levesque
approximation. Known exact consistency conditions are used to express
, , and in terms of the radial distribution
at contact of the one-component system. Two specific proposals consistent with
the above conditions (a quadratic form and a rational form) are made for the
-dependence of . For one-dimensional systems, the proposals for
the contact values reduce to the exact result. Good agreement between the
predictions of the proposals and available numerical results is found for
, 3, 4, and 5.Comment: 10 pages, 11 figures; Figure 1 changed; Figure 5 is new; New
references added; accepted for publication in J. Chem. Phy
Fourth virial coefficients of asymmetric nonadditive hard-disc mixtures
The fourth virial coefficient of asymmetric nonadditive binary mixtures of
hard disks is computed with a standard Monte Carlo method. Wide ranges of size
ratio () and nonadditivity () are
covered. A comparison is made between the numerical results and those that
follow from some theoretical developments. The possible use of these data in
the derivation of new equations of state for these mixtures is illustrated by
considering a rescaled virial expansion truncated to fourth order. The
numerical results obtained using this equation of state are compared with Monte
Carlo simulation data in the case of a size ratio and two
nonadditivities .Comment: 9 pages, 7 figures; v2: section on equation of state added; tables
moved to supplementary material
(http://jcp.aip.org/resource/1/jcpsa6/v136/i18/p184505_s1#artObjSF
Comment on "Theory and computer simulation for the equation of state of additive hard-disk fluid mixtures"
A flaw in the comparison between two different theoretical equations of state
for a binary mixture of additive hard disks and Monte Carlo results, as
recently reported in C. Barrio and J. R. Solana, Phys. Rev. E 63, 011201
(2001), is pointed out. It is found that both proposals, which require the
equation of state of the single component system as input, lead to comparable
accuracy but the one advocated by us [A. Santos, S. B. Yuste, and M. L\'{o}pez
de Haro, Mol. Phys. 96, 1 (1999)] is simpler and complies with the exact limit
in which the small disks are point particles.Comment: 4 pages, including 1 figur
Organização da diversidade de acessos de mandioca com alta similaridade genética com base em marcadores SNPs e microssatélites.
O fato de a mandioca (Manihot esculenta Crantz) ser uma planta nativa do Brasil e a ampla gama de locais de cultivo no país amplificam a diversidade fenotípica observada nos acessos de germoplasma desta espécie. Por outro lado, muitos nomes são dados a um mesmo genótipo e ao mesmo tempo diferentes acessos possuem um mesmo nome
Magnetic Properties of the Metamagnet Ising Model in a three-dimensional Lattice in a Random and Uniform Field
By employing the Monte Carlo technique we study the behavior of Metamagnet
Ising Model in a random field. The phase diagram is obtained by using the
algorithm of Glaubr in a cubic lattice of linear size with values ranging
from 16 to 42 and with periodic boundary conditions.Comment: 4 pages, 6 figure
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