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31.
S.?Didaoui-NemouchiEmail author A.?Ait-Kaci M.?Rogalski 《Journal of Thermal Analysis and Calorimetry》2005,79(1):85-88
Enthalpies of mixing H have been measured for liquid binary mixtures of diisopropylether (DIPE)+benzene or cyclohexane and for liquid ternary mixtures diisopropylether+benzene+cyclohexane at 303.15 K and constant pressure using a C80 calorimeter. A Redlich-Kister type equation was used to correlate experimental results. 相似文献
32.
The Landau-Lifshitz fluctuating fluxes in fluctuating hydrodynamics are derived from the deterministic Boltzmann equation with the aid of a reduction method developed by Fujisaka and Mori. Thus it is shown that the hydrodynamic fluctuations innonequilibrium systems are generated by the reduction of variables from the-space distribution function to its five momentum moments, i.e., the hydrodynamic variables. This differs from the Bixon-Zwanzig and Fox-Uhlenbeck theories, in which the Landau-Lifshitz fluctuating fluxes are derived from the molecular fluctuating force in thestochastic Boltzmann-Langevin equation, which is, however, negligible in nonequilibrium systems. Thus the present method improves the Chapman-Enskog reduction method so as to include the hydrodynamic fluctuations generated by the reduction of variables.Supported in part by the Scientific Research Fund of the Ministry of Education. 相似文献
33.
Akira Onuki 《Journal of statistical physics》1978,18(5):475-499
A master equation is derived microscopically to describe the fluctuating motion of the particle density in . space. This equation accounts for the drift motion of particles and is valid for any inhomogeneous gas. The Boltzmann equation is obtained from the first moment of this equation by neglecting the second cumulant (the pair correlation function). The successive moments form coarse-grained BBGKY-like hierarchy equations, in which small spatial regions with rij < the force range are smeared out. These hierarchy equations are convenient for investigating the nonequilibrium long-range pair correlation function, which arises mainly from sequences of isolated binary collisions and gives rise to the much-discussed long-time tail and the logarithmic term in the density expansion of transport coefficients. It is shown to have a spatial long tail, like the Coulombic potential, in a steady laminar flow. The stochastic nature of the nonlinear Boltzmann-Langevin equation is also investigated; the random source term is found to be expressed as a linear superposition of Poisson random variables and to become Gaussian in special cases. 相似文献
34.
Herbert Spohn 《Journal of statistical physics》1977,17(6):385-412
A single (nonrelativistic, spinless) electron subject to a constant external electric field interacts with impurities located on an infinitely extended lattice by a potential of random strength. The random strength is given by a field of Gaussian random variables. We show the existence of the averaged dynamics and prove that in the weak coupling limit, 0, 2
t= fixed, one obtains the usual transport equation for the velocity distribution.Work supported by a Max Kade Foundation fellowship.On leave of absence of the Fachbereich Physik der Universität München. 相似文献
35.
John L. Spouge 《Journal of statistical physics》1983,31(2):363-378
This paper gives the equilibrium distribution of polymer sizes for Flory'sA
g
RB
f–g model of polymerization. In this model, the polymers are composed of structural units withg functional groups of the typeA and (f-g) functional groups of the typeB. Reaction is subject to three conditions: (1) Functional groups of the typeA react only with those of typeB, and vice versa. (2) Intramolecular reactions do not occur [and therefore only branched-chain (noncyclic) polymers and formed]. (3) Subject to conditions (1) and (2), all functional groups are equally reactive. The derivation employs Stockmayer's statistical mechanical method (first used on Flory'sRA
f model), coupled with a recursion giving the number of distinct polymers which may be assembled fromk units of theA
g
RB
f–g type. We also give distributions for a limiting case of theA
g
RB
f–g model, the so-calledA
g
RB
model. This paper completes the solution of the Smoluchowski coagulation equation (monodisperse case) for the kernelsa
ij =A + B(i +j)+ Cij. The proof will be given in another publication. 相似文献
36.
E. Rotureau 《European Polymer Journal》2006,42(5):1086-1092
Amphiphilic polysaccharides have been obtained by hydrophobic modification of a neutral bacterial polysaccharide, dextran. Various amounts and types of aliphatic hydrocarbon groups have been attached to dextran.The solution behaviour of unmodified dextran samples and amphiphilic dextran derivatives is characterized by viscometric measurements. The overall viscosity behaviour of unmodified polysaccharides is described up to C × [η] = 3, using the equation of Fedors [Fedors RF. Polymer 1979;20:225] which involves only a concentration parameter. The latter is shown to depend on the hydrodynamic volume of the macromolecules in solution.The equation of Fedors is shown to conveniently estimate the viscosity behaviour of amphiphilic dextran derivatives up to C × [η] = 1. The interdependence between Fedors parameter and other viscometric characteristics (intrinsic viscosity, Huggins coefficient) is evidenced. These results are extended to the data of other authors. 相似文献
37.
A model of disordered medium is proposed to describe the monolayer adsorption isotherm on heterogeneous surfaces. The model
is based on the premise that adsorption medium consists of separate regions in each of which there is a permanent local equilibrium
constant, the character of the changes of which is determined by the disorder parameter of the medium.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 3, pp. 189–193, May–June, 2006. 相似文献
38.
Shinsaku Fujita 《Theoretical chemistry accounts》1990,78(1):45-63
Summary A coset representation (G(/G
i
)), which is defined algebraically by a coset decomposition of a finite groupG by its subgroupG
i
, is shown to be a method for the decomposition of a regular body into its point group orbits. This proof also shows that each member of theG(/G
i
) orbit belongs to theG
i
site-symmetry. In addition, a general equation concerning the multiplicities of such coset representations is derived and shown to involve Brester's equations and thek-value equations of framework groups as special cases. The relationship of the coset representation and the site-symmetry affords a general procedure for obtaining symmetry adapted functions. 相似文献
39.
Shuping Chen 《Applied Mathematics and Optimization》1992,26(1):95-110
Necessary and sufficient conditions are established in this paper for the existence of positive- and/or negative-definite solutions to the algebraic Riccati equation with indefinite coefficient. An iterative procedure is also given for computing such a solution.Project supported by the National Science Foundation of China and by the special program of the State Education Commission of China under grant 9033507. 相似文献
40.
Tomislav P. Živković 《Journal of mathematical chemistry》2002,32(1):39-71
Interaction of quantum system S
a
described by the generalised × eigenvalue equation A|
s
=E
s
S
a
|
s
(s=1,...,) with quantum system S
b
described by the generalised n×n eigenvalue equation B|
i
=
i
S
b
|
i
(i=1,...,n) is considered. With the system S
a
is associated -dimensional space X
a
and with the system S
b
is associated an n-dimensional space X
n
b
that is orthogonal to X
a
. Combined system S is described by the generalised (+n)×(+n) eigenvalue equation [A+B+V]|
k
=
k
[S
a
+S
b
+P]|
k
(k=1,...,n+) where operators V and P represent interaction between those two systems. All operators are Hermitian, while operators S
a
,S
b
and S=S
a
+S
b
+P are, in addition, positive definite. It is shown that each eigenvalue
k
i
of the combined system is the eigenvalue of the × eigenvalue equation
. Operator
in this equation is expressed in terms of the eigenvalues
i
of the system S
b
and in terms of matrix elements
s
|V|
i
and
s
|P|
i
where vectors |
s
form a base in X
a
. Eigenstate |
k
a
of this equation is the projection of the eigenstate |
k
of the combined system on the space X
a
. Projection |
k
b
of |
k
on the space X
n
b
is given by |
k
b
=(
k
S
b
–B)–1(V–
k
P})|
k
a
where (
k
S
b
–B)–1 is inverse of (
k
S
b
–B) in X
n
b
. Hence, if the solution to the system S
b
is known, one can obtain all eigenvalues
k
i
} and all the corresponding eigenstates |
k
of the combined system as a solution of the above × eigenvalue equation that refers to the system S
a
alone. Slightly more complicated expressions are obtained for the eigenvalues
k
i
} and the corresponding eigenstates, provided such eigenvalues and eigenstates exist. 相似文献