Generation of strongly chaotic beats

The letter proposes a procedure for generation of strongly chaotic beats that have been hardly obtainable hitherto. The beats are generated in a nonlinear optical system governing second-harmonic generation of light. The proposition is based on the concept of an optical coupler but can be easily adopted to other nonlinear systems and Chua's circuits.Comment: 10 pages, 4 figures, accepted for publication in Int.J.Bif.Chao

Nanostructured poly(benzimidazole) membranes by N-alkylation

Modification of poly(benzimidazole) (PBI) by N-alkylation leads to polymers capable of undergoing microphase separation. Polymers with different amounts of C18 alkyl chains have been prepared. The polymers were analyzed by spectroscopy, thermal analysis, electron microscopy and X-ray scattering. The impact of the amount of alkyl chains on the observed microphase separation was analyzed. Membranes prepared from the polymers do show microphase separation, as evidenced by scattering experiments. While no clear morphology could be derived for the domains in the native state, evidence for the formation of lamellar morphologies upon doping with phosphoric acid is provided. Finally, the proton conductivity of alkyl-modified PBI is compared with that of pure PBI, showing that the introduction of alkyl side chains does not result in significant conductivity changes

Main-chain poly(ionic liquid)-derived nitrogen-doped micro/mesoporous carbons for CO₂ capture and selective aerobic oxidation of alcohols

Sustainable development and the recent fast-growing global demands for energy and functional chemicals urgently call for effective methods for CO2 remediation and efficient metal-free catalysts for selective oxidation of aromatic alcohol. Herein, a unique main-chain poly(ionic liquid) (PIL) is employed as the precursor to prepare nitrogen-doped micro/mesoporous carbons via simultaneous carbonization and activation, which bear high yield, large specific surface area above 1700 m2 g−1 and rich nitrogen dopant. The porous carbon products deliver a high CO2 adsorption capacity up to 6.2 mmol g−1 at 273 K and 1 bar with outstanding reversibility and satisfactory selectivity. Besides, they work excellently as metal-free carbocatalysts for the selective aerobic oxidation of benzyl alcohol to benzaldehyde with high selectivity. It is believed that this work not only provides a facile approach to prepare nitrogen-doped porous carbon, but also advances the related research in the fields of environment and catalysis

On Uniquely Closable and Uniquely Typable Skeletons of Lambda Terms

Uniquely closable skeletons of lambda terms are Motzkin-trees that predetermine the unique closed lambda term that can be obtained by labeling their leaves with de Bruijn indices. Likewise, uniquely typable skeletons of closed lambda terms predetermine the unique simply-typed lambda term that can be obtained by labeling their leaves with de Bruijn indices. We derive, through a sequence of logic program transformations, efficient code for their combinatorial generation and study their statistical properties. As a result, we obtain context-free grammars describing closable and uniquely closable skeletons of lambda terms, opening the door for their in-depth study with tools from analytic combinatorics. Our empirical study of the more difficult case of (uniquely) typable terms reveals some interesting open problems about their density and asymptotic behavior. As a connection between the two classes of terms, we also show that uniquely typable closed lambda term skeletons of size $3n+1$ are in a bijection with binary trees of size $n$.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

Diversidad genética de cepas españolas de Xanthomonas arboricola pv. pruni agente causal de la mancha bacteriana de los frutales de hueso y del almendro

PublishedTrabajo financiado por el Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, proyecto RTA2011-00140-d03-0