It was found that specific surface area of the obtained beads is strongly dependent on the diluent system and the type of cross-linker and achieves value from 27 to 845 m(2)/g. To determine the influence of chemical structure of cross-linkers on the selectivity and polarity of the copolymers, inverse gas chromatography was applied. In addition, VPDVB and VPDMN copolymers were modified by sulfonation into cation-exchangers with cation exchange capacity equal 1.98 and 2.31 mmol/g, respectively. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012″
“Using numerical
simulations, we investigate the realization of self-focusing media using two-dimensional graded photonic crystals and their applications for imaging and non-imaging purposes. The two-dimensional graded photonic crystals consist of spatially varying cylindrical holes
drilled in a dielectric host. By controlling the gradient Ro-3306 manufacturer of the refractive index and the thickness of the self-focusing medium, it is possible to selleck screening library obtain either a focusing lens with Fourier transforming capabilities or an imaging lens, which produces inverted images. Non-imaging applications include a simple antenna for directive emission obtained from the focusing lens, whereas a directional cloak is obtained by modifying the imaging lens. Graded photonic crystal based devices work well up to the Bragg frequencies. They are compact, made from lossless dielectrics, and compatible with planar lithographic techniques, so they can find applications in a broad frequency range, even at the optical frequencies. (C) 2011 American Institute of Physics. [doi:10.1063/1.3630116]“
“In natural ecosystems, hundreds of species typically share the same environment and are connected by a dense network of interactions such as predation or competition for resources. Much is known about how fixed ecological niches can determine species abundances in such systems, but far less attention has been paid to patterns of abundances in randomly varying environments.
Here, we study this question in a simple model DAPT nmr of competition between many species in a patchy ecosystem with randomly fluctuating environmental conditions. Paradoxically, we find that introducing noise can actually induce ordered patterns of abundance-fluctuations, leading to a distinct periodic variation in the correlations between species as a function of the phenotypic distance between them; here, difference in growth rate. This is further accompanied by the formation of discrete, dynamic clusters of abundant species along this otherwise continuous phenotypic axis. These ordered patterns depend on the collective behavior of many species; they disappear when only individual or pairs of species are considered in isolation.