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91.
Xiao-Chun Wang Lei Zhang Qing-Tao Gong Lu Zhang Lan Luo Zhen-Quan Li 《Journal of Dispersion Science and Technology》2013,34(1):137-143
Foaming properties and the dynamic surface tension (DST) were carried out with aqueous solutions of sodium branched-alkyl benzene sulfonates to elucidate the relationship between foaming properties and surfactant structures. The parameters of the DST (t*, n, R 1/2 ) are correlated with the foaming ability for alkyl benzene sulfonates with benzene ring substituting at positions 2, 4, and 8 of hexadecane. The parameters of the DST (t*, n, R 1/2 ) are correlated with the foaming ability of the same surfactant solutions. The results indicated that the molecular diffusion in the solution, adsorption, and arrangement at the air/water interface were changed with different molecular structures: changing the substituted position of benzene ring from 2 to 8 of hexadecane, the value of t* and n decrease, and the value of R 1/2 increases, which lead to the high dynamic surface activity and high foam volume. The foam stability is correlated with the high surface dilational elasticity and the strength of surface monolayer: changing the substituted position of benzene ring from 2 to 8 of hexadecane, the branched-alkyl chain becomes more flexible, which is characterized by densely packed adsorbed molecules and high film elasticity of the adsorption film. Therefore, the foam stability increases. 相似文献
92.
LU Ke LIN Zhen-Quan SUN Yun-Fei 《理论物理通讯》2008,50(7):105-110
We proposed an aggregation model of two species aggregates of fitness and population to study the interaction between the two species in their exchange-driven processes of the same species by introducing the monomer birth of fitness catalyzed by the population, where the fitness aggregates perform self-death process and the population aggregates perform self-birth process. The kinetic behaviors of the aggregate size distributions of the fitness and population were analyzed by the rate equation approach with their exchange rate kernel K1(k,j) = K1kj and K2(k,j) = K2kj, the fitness aggregate's self-death rate kernel J1 ( k ) = J1 k, population aggregate's self-birth rate kernel J2( k ) = J2k and population-catalyzed fitness birth rate kernel I(k,j) = Ikj'. The kinetic behavior of the fitness was found depending crucially on the parameter v, which reflects the dependence of the population-catalyzed fitness birth rate on the size of the catalyst (population) aggregate. (i) In the v ≤ 0 case, the effect of catalyzed-birth of fitness is rather weak and the exchange-driven aggregation and self-death of the fitness dominate the process, and the fitness aggregate size distribution αk(t) does not have scale form. (ii) When v ≥0, the effect of the population-catalyzed birth of fitness gets strong enough, and the catalyzed-birth and self-death of the fitness aggregates, together with the self-birth of the population aggregates dominate the evolution process of the fitness aggregates. The aggregate size distribution αk (t) approaches a generalized scaling form. 相似文献
93.
YANG Shun-You ZHU Sheng-Qing KE Jian-Hong LIN Zhen-Quan 《理论物理通讯》2008,50(9):787-792
We propose a two-species infection model, in which an infected aggregate can gain one monomer from a healthy one due to infection when they meet together. Moreover, both the healthy and infected aggregates may lose one monomer because of self-death, but a healthy aggregate can spontaneously yield a new monomer. Consider a simple system in which the birth/death rates are directly proportional to the aggregate size, namely, the birth and death rates of the healthy aggregate of size k are J1 k and J2k while the self-death rate of the infected aggregate of size k is J3k. We then investigate the kinetics of such a system by means of rate equation approach. For the J1 〉 J2 case, the aggregate size distribution of either species approaches the generalized scaling form and the typical size of either species increases wavily at large times. For the J1 = J2 case, the size distribution of healthy aggregates approaches the generalized scaling form while that of infected aggregates satisfies the modified scaling form. For the J1 〈 J2 case, the size distribution of healthy aggregates satisfies the modified scaling form, but that of infected aggregates does not scale. 相似文献
94.
We further study the kinetic behavior of the exchange-driven
growth with birth and death for the case of birth rate kernel
being less than that of death based on the mean-field theory. The
symmetric exchange rate kernel is
K(k,j)=K'(k,j)=Ikjυ,
and the birth and death rates are proportional to the aggregate's
size. The long time asymptotic behavior of the aggregate size
distribution a_k(t) is found to obey a much unusual scaling law
with an exponentially growing scaling function Φ(x)=exp(x). 相似文献