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Expansive soil is mainly composed of hydrophilic minerals, and shows significant deformation characteristics after watering, which often causes great harm to engineering construction. In this study, numerical analyses were conducted to investigate the effects of anti-sliding piles on the deformation mechanisms of a bridge foundation in an expansive soil slope. It was found that deformation of the bridge foundation was affected not only by rainfall-induced swelling of expansive soil, decrease in strength, and sliding force, but also by indirect effects of anti-slide pile resistance and space constraints. Anti-slide piles on expansive soil slopes were likely to exacerbate the effect of slope deformation and/or landslides on the bridge foundation. When the distance from the bridge foundation was large, the effect of the anti-sliding piles on the bridge foundation was small; otherwise, the effect was large. [ABSTRACT FROM AUTHOR]

Remarkable and repeatable negative differential resistance (NDR) phenomenon was observed in a metal-polymer-metal structure diode based on bishexyloxy-divinyl-benzene-alt-diketopyrrolopyrrole (C6DPPPPV), a type of donor-acceptor (D-A) conjugated copolymer. Thickness dependence of the devices implied that the observed NDR characteristics were bulk-controlled. The device performance was considered to depend on the slow trapping and releasing processes related to the local deep states, which was enhanced by the growth and thermal rupture of conducting filaments through the organic layer. The results suggest that the D-A conjugated copolymer is a promising memory material based on NDR effect. [ABSTRACT FROM AUTHOR]

A novel organic electron acceptor, N,N′-dipyrimidinyl-3,4,9,10-perylene-tetracarboxylic diimide (DMP), was designed and synthesized. The molecular structure was characterized by FTIR spectrum and elemental analysis. By cyclic voltammetry measurements, DMP was found to possess a lower LUMO energy level than N,N′-diphenyl-3,4,9,10-perylene-tetracarboxylic diimide due to the stronger electron-withdrawing pyrimidinyl group than the phenyl group. Fluorescence quenching is observed in a dual-layer film consisting of a DMP layer and a C60 layer and was attributed to the charge transfer at the interface due to the energy level offset between DMP and C60. [ABSTRACT FROM AUTHOR]