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The solubilities of methane, ethane, propane, and n-butane were measured in aqueous solutions of sodium dodecylsulfate (NaDS) (0–0.1M) from 15 to 27°C. From these measurements the standard Gibbs energies, entropies, and enthalpies for the process of transferring the solute molecules from the gaseous phase into the solutions were calculated. An approximate relationship was found relating the volume fraction of the micelles to NaDS concentration. 相似文献
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The ostwald absorption coefficient of argon was measured in aqueous solutions of two surfactants; sodium n-octanoate and in sodium dodecylsulfate, at several concentrations and at a few temperatures between 10–25°C. The free energies, entropies and enthalpies of solution were computed. A tentative interpretation of the results is given, based on a competition between the solubilization and the salting-out effects of the surfactants. 相似文献
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We find a general class of nontrivial stationary states in inelastic gases where, due to dissipation, energy is transferred from large velocity scales to small velocity scales. These steady states exist for arbitrary collision rules and arbitrary dimension. Their signature is a stationary velocity distribution f(v) with an algebraic high-energy tail, f(v) approximately v(-sigma). The exponent sigma is obtained analytically and it varies continuously with the spatial dimension, the homogeneity index characterizing the collision rate, and the restitution coefficient. We observe these stationary states in numerical simulations in which energy is injected into the system by infrequently boosting particles to high velocities. We propose that these states may be realized experimentally in driven granular systems. 相似文献
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We study experimentally statistical properties of the opening times of knots in vertically vibrated granular chains. Our measurements are in good qualitative and quantitative agreement with a theoretical model involving three random walks interacting via hard-core exclusion in one spatial dimension. In particular, the knot survival probability follows a universal scaling function which is independent of the chain length, with a corresponding diffusive characteristic time scale. Both the large-exit-time and the small-exit-time tails of the distribution are suppressed exponentially, and the corresponding decay coefficients are in excellent agreement with theoretical values. 相似文献
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Ben-Naim A 《The Journal of chemical physics》2008,128(8):084510
Two sets of quantities are calculated for two-component mixtures in one dimension. One consists of the traditional excess thermodynamic quantities which provide global information on the mixtures. The second, referred to as local properties, consists of the Kirkwood-Buff integrals, local composition, solvation, and preferential solvation quantities. In this part, we discuss simple particles interacting via either square-well potential or hard rod potential. It is shown that a host of new information can be obtained from the local properties of the mixtures which supplements the information conveyed by the global properties. 相似文献
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The paper presents a method for transforming a given sound and complete n-sequent proof system into an equivalent sound and complete system of ordinary sequents. The method is applicable to a large,
central class of (generalized) finite-valued logics with the language satisfying a certain minimal expressiveness condition.
The expressiveness condition decrees that the truth-value of any formula φ must be identifiable by determining whether certain
formulas uniformly constructed from φ have designated values or not. The transformation preserves the general structure of
proofs in the original calculus in a way ensuring preservation of the weak cut elimination theorem under the transformation.
The described transformation metod is illustrated on several concrete examples of many-valued logics, including a new application
to information sources logics. 相似文献
8.
E. Ben-Naim P. L. Krapivsky 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(5):145
We study the classic Susceptible-Infected-Recovered (SIR) model for the spread of an infectious disease. In this stochastic
process, there are two competing mechanism: infection and recovery. Susceptible individuals may contract the disease from
infected individuals, while infected ones recover from the disease at a constant rate and are never infected again. Our focus
is the behavior at the epidemic threshold where the rates of the infection and recovery processes balance. In the infinite
population limit, we establish analytically scaling rules for the time-dependent distribution functions that characterize
the sizes of the infected and the recovered sub-populations. Using heuristic arguments, we also obtain scaling laws for the
size and duration of the epidemic outbreaks as a function of the total population. We perform numerical simulations to verify
the scaling predictions and discuss the consequences of these scaling laws for near-threshold epidemic outbreaks. 相似文献
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E. Ben-Naim F. Vazquez S. Redner 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,49(4):531-538
We model the dynamics of social structure by a simple interacting particle
system. The social standing of an individual agent is represented by an
integer-valued fitness that changes via two offsetting processes. When two
agents interact one advances: the fitter with probability p and the less
fit with probability 1-p. The fitness of an agent may also decline with
rate r. From a scaling analysis of the underlying master equations for
the fitness distribution of the population, we find four distinct social
structures as a function of the governing parameters p and r. These
include: (i) a static lower-class society where all agents have finite
fitness; (ii) an upwardly-mobile middle-class society; (iii) a hierarchical
society where a finite fraction of the population belongs to a middle class
and a complementary fraction to the lower class; (iv) an egalitarian
society where all agents are upwardly mobile and have nearly the same
fitness. We determine the basic features of the fitness distributions in
these four phases. 相似文献
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We study domain distributions in the one-dimensional Ising model subject to zero-temperature Glauber and Kawasaki dynamics. The survival probability of a domain, S(t)~t ?ψ, and an unreacted domain, Q 1(t)~t ?δ, are characterized by two independent nontrivial exponents. We develop an independent interval approximation that provides close estimates for many characteristics of the domain length and number distributions including the scaling exponents. 相似文献