A periodic elastic medium in which periodicity is relevant

We analyze, in both (1+1)- and (2+1)- dimensions, a periodic elastic medium in which the periodicity is such that at long distances the behavior is always in the random-substrate universality class. This contrasts with the models with an additive periodic potential in which, according to the field theoretic analysis of Bouchaud and Georges and more recently of Emig and Nattermann, the random manifold class dominates at long distances in (1+1)- and (2+1)-dimensions. The models we use are random-bond Ising interfaces in hypercubic lattices. The exchange constants are random in a slab of size $L^{d-1} \times \lambda$ and these coupling constants are periodically repeated along either {10} or {11} (in (1+1)-dimensions) and {100} or {111} (in (2+1)-dimensions). Exact ground-state calculations confirm scaling arguments which predict that the surface roughness $w$ behaves as: $w \sim L^{2/3}, L \ll L_c$ and $w \sim L^{1/2}, L \gg L_c$, with $L_c \sim \lambda^{3/2}$ in $(1+1)$-dimensions and; $w \sim L^{0.42}, L \ll L_c$ and $w \sim \ln(L), L \gg L_c$, with $L_c \sim \lambda^{2.38}$ in $(2+1)$-dimensions.Comment: Submitted to Phys. Rev.

Wall forces on a sphere in a rotating liquid-filled cylinder

We experimentally study the behavior of a particle slightly denser than the surrounding liquid in solid body rotating flow. Earlier work revealed that a heavy particle has an unstable equilibrium point in unbounded rotation flows. In the confinement of the rotational flow by a cylindrical wall a heavy sphere with density 1.05 g/cm$^3$ describes an orbital motion in our experiments. This is due to the effect of the wall near the sphere, i.e. a repulsive force ($F_w$). We model $F_w$ on the sphere as a function of the distance from the wall ($L$): $F_W \propto L^{-4}$ as proposed by Takemura and Magnaudet (2003). Remarkably, the path from the model including $F_w$ reproduce the experimentally measured trajectory. In addition during an orbital motion the particle does not spin around its axis, and we provide a possible explanation for this phenomenon.Comment: 11 pages, 11 figure

Revision der Gattung Oncophorus (Musci, Dicranaceae)

The 12 species so far comprised in the genus Oncophorus are reduced to 6. Oncophorus fauriei Card. ex Ihs. and O. muratae Broth. ex Ihs. are synonymous with C. crispifolius, O. decumbens (Thwait. & Mitt.) Broth. is a species of Dicranum, O. gracilentus Zeng is a species of Dicranella, O. gracillimus Dix. is a synonym of O. wahlenbergii, O. sardous Herz. a synonym of O. virens.Von den 12 bisher in der Gattung Oncophorus eingeschlossenen Arten werden 6 anerkannt. Oncophorus fauriei Card. ex Ihs. und O. mutratae Broth. ex Ihs. sind ein Synonyme von C. crispifolius, O. decumbens (Thwait. & Mitt.) Broth. ist ein Dicranum, O. gracilentus Zeng gehört zu Dicranella, O. gracillimus Dix. ist ein Synonym von O. wahlenbergii, O. sardous Herz. ein Synonym von O. virens

2D-Delocalized vs Confined Diradicals

Resumen de la comunicación oral seleccionadaDiradicals are beautiful chemical objects where the more basic and intricate aspects of the chemical bonding are revealed.1 Not this being important enough, nowadays, diradical-based substrates are becoming very appealing for new organic electronic applications. We focus here in conjugated organic diradicals formed by competition between non-aromatic quinoidal structures and their canonical aromatic forms. How this quinoidal(closed-shell)-vs-aromatic(open-shell) energetic balance producing the diradical is affected by several situations has been our objective in the last few years.2 Now, we focusses on how the properties of diradicals are influenced when several diradical canonical forms are available in such a way that create a 2D (i.e., bidimensional) electron delocalization surface in which the diradical substructures are in cross-conjugation mode producing the curious effect of diradical confinement.3 Herein, the diradical molecular properties of compound 1 in Figure 1 will be discussed in connection with 2D delocalization, cross-conjugation and surface confinement. 1. Rajca, A., Chem. Rev., 1994, 94, 871; Abe, M., Chem. Rev. 2013, 113, 7011. 2. Zeng, Z.; X. Shi, L.; Chi, C.; Casado, J.; Wu, J. Chem. Soc. Rev. 2015, 44, 6578. 3. Yuan, D.; Huang, D.; Medina Rivero, S.; Carreras, A.; Zhang, C.; Zou, Y.; Jiao, X.; McNeill, C.R.; Zhu, X.; Di, C.; Zhu, D.; Casanova, D.; Casado, J. CHEM, 2019, accepted.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Non equilibrium dynamics below the super-roughening transition

The non equilibrium relaxational dynamics of the solid on solid model on a disordered substrate and the Sine Gordon model with random phase shifts is studied numerically. Close to the super-roughening temperature $T_g$ our results for the autocorrelations, spatial correlations and response function as well as for the fluctuation dissipation ratio (FDR) agree well with the prediction of a recent one loop RG calculation, whereas deep in the glassy low temperature phase substantial deviations occur. The change in the low temperature behavior of these quantities compared with the RG predictions is shown to be contained in a change of the functional temperature dependence of the dynamical exponent $z(T)$, which relates the age $t$ of the system with a length scale ${\cal L}(t)$: $z(T)$ changes from a linear $T$-dependence close to $T_g$ to a 1/T-behavior far away from $T_g$. By identifying spatial domains as connected patches of the exactly computable ground states of the system we demonstrate that the growing length scale ${\cal L}(t)$ is the characteristic size of thermally fluctuating clusters around ``typical'' long-lived configurations.Comment: RevTex

Interfaces, Volume 7, Issue 1 - Winter 2004

Facility Focus (I): Multipurpose X-Ray System Zeng Named Guggenheim Fellow Sigma Xi Honors to CMRA Faculty, Staff and Students Best Paper Awards Degree of Doctor Honoris Causa Recent Patents Facility Focus(II): Equipment Upgrade in Electron Microscopy CMRA Welcomes Fereydoon Namavar Research Spotlight: Stephen Ducharme Spinning Continuous Fibers for Nanotechnolog

Stability of Mann and Ishikawa iterative processes with errors for a class of nonlinear variational inclusions

Under the lack of the condition , some new convergence and stability theorems of Mann and Ishikawa iterative processes with errors for solutions to variational inclusions involving accretive mappings in real reflexive Banach spaces are established. The main results of this paper extend and improve the corresponding results obtained by Chang, Ding, Hassouni and Moudafi, Huang, Kazmi, Noor, Siddiqi and Ansari and Zeng