No abstract

A rough-thin-film system, deposited on silicone oil drop surfaces by a rf-magnetron sputtering method, has been fabricated and its structure as well as I-V characteristics have been studied. A characteristic surface morphology at the micrometer scale is observed. The anomalous deposition rate, which strongly depends on the nominal film thickness, can be interpreted under the assumption of the second evaporating and the penetrating effects. We find I c ϰR 0 Ϫ␣ , with ␣ϭ0.52Ϯ0.06, where R 0 and I c are the zero power resistance and the breakdown current, respectively. The importance of the liquid substrates is discussed.

We propose an exchange-driven aggregation growth model of population and assets with mutually catalyzed birth to study the interaction between the population and assets in their exchange-driven processes. In this model, monomer (or equivalently, individual) exchange occurs between any pair of aggregates of the same species (population or assets). The rate kernels of the exchanges of population and assets are K(k,l) = Kkl and L(k,l) = Lkl , respectively, at which one monomer migrates from an aggregate of size k to another of size l. Meanwhile, an aggregate of one species can yield a new monomer by the catalysis of an arbitrary aggregate of the other species. The rate kernel of asset-catalyzed population birth is I(k,l) = Iklmu [and that of population-catalyzed asset birth is J(k,l) = Jklnu], at which an aggregate of size k gains a monomer birth when it meets a catalyst aggregate of size l . The kinetic behaviors of the population and asset aggregates are solved based on the rate equations. The evolution of the aggregate size distributions of population and assets is found to fall into one of three categories for different parameters mu and nu: (i) population (asset) aggregates evolve according to the conventional scaling form in the case of mu < or = 0 (nu < or = 0), (ii) population (asset) aggregates evolve according to a modified scaling form in the case of nu = 0 and mu > 0 (mu = 0 and nu > 0 ), and (iii) both population and asset aggregates undergo gelation transitions at a finite time in the case of mu = nu > 0.

The diffusion behavior of silver islands on charged silicone oil surfaces has been studied. Compact Ag islands with an average diameter of 1.2 m form after thermal deposition of silver on a charged silicone oil surface. In contrast to the behavior of the uncharged oil surface, no aggregation of the Ag islands is observed. Instead the average distance of the islands increases as the islands diffuse toward the edge of the oil substrate. This process is driven by the repulsive Coulomb interaction. An exponential decay of the island density n with time t results everywhere on the oil surface, and the corresponding time constant O f ranges between 1.0 ϫ10 Ϫ4 and 2.0ϫ10 Ϫ4 s Ϫ1 . In the central area of the substrate, the relative speed V between two islands increases linearly with their distance L according to V f it ϭHL, where V f it is the linear fit speed of V. The slope H is of the order of 2.0ϫ10 Ϫ4 -3.0ϫ10 Ϫ4 s Ϫ1 after the deposition, and decreases with time. Our theoretical analysis indicates that O f ϷH, in agreement with the experimental finding. The experiment also shows that this nonequilibrium expansive diffusion already starts at the early stage of deposition. During their motion, the islands must carry a small fraction of the electron charge on the oil surface. After the islands reach the sample edge, they form a band-shaped silver film along the border. This results in the accumulation of charge, which slows down the speed of the remaining islands, which diffuse toward the edge.