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In this paper, we introduce a class of predator-prey system with general functional response, whose harvesting policy is modeled by a discontinuous function. Based on the differential inclusions theory, topological degree theory in set-valued analysis and generalized Lyapunov approach, we analyze the existence, uniqueness and global asymptotic stability of positive periodic solution. In particular, a series of useful criteria on existence, uniqueness and global asymptotic stability of the positive equilibrium point are established for the autonomous system corresponding to the non-autonomous biological and mathematical model with a discontinuous right-hand side. Moreover, some new sufficient conditions are provided to guarantee the global convergence in measure of harvesting solution and convergence in finite time of any positive solution for the autonomous discontinuous biological system. The obtained results, which improve and generalize previous works on dynamical behavior in the literature, are of interest for understanding and designing biological system with not only continuous or even Lipschitz continuous but also discontinuous harvesting function. Finally, we give three examples with numerical simulations to show the applicability and effectiveness of our main results. [ABSTRACT FROM AUTHOR]

Conjugated polymers having good electrochemical and thermal stability are highly desired in optoelectronics. We report a new polythiophene consisting of alternating 4,4′-didodecyl-2,2′-bithiophene and terthiophene units (HPL1) synthesized via Stille coupling reaction. The optical band gap of HPL1 (1.92 eV) is similar to that of regioregular poly(3-hexylthiophene) (rr-P3HT, 1.89 eV). In comparison to rr-P3HT, the HPL1 when subjected to the cyclic voltammetry as thin film shows much superior electrochemical stability and a lower highest occupied molecular orbital energy level (−4.87 eV for rr-P3HT and −4.95 eV for HPL1). The transient photoluminescence study of HPL1 and rr-P3HT shows that both materials have two exciton decay processes, and the excitons of rr-P3HT are quenched more quickly. The onset decomposition, Td for rr-P3HT (465°C) is 4°C lower than HPL1 (469°C). Preliminary photovoltaic study disclosed that the polymer solar cell based on HPL1:[6,6]-phenyl-C61-butyric acid methyl ester blend showed a power conversion efficiency of 0.63%, with a Voc of 0.6 V, and a short circuit current ( Jsc) of 2.79 mA cm−2 under AM 1.5 illumination (100 mW cm−2). The whole study provided an important example to design new electrochemically and thermally stable polymers with longer exciton life time for application in bulk heterojunction polymer solar cells. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012 [ABSTRACT FROM AUTHOR]