In this work, effect of nano-sized SiO 2 and micro-sized hexagon boron nitride (h-BN) on charge transport behavior of low-density polyethylene (LDPE) has been investigated. LDPE based micro-nanocomposites samples were prepared through hot-press method by adding 20 nm-SiO 2 and 5 µm-h-BN as the fillers. Isothermal surface potential decay measurement was carried out with sample temperature of 40 °C and relative humidity of 23%-29% to obtain trap depth, carrier mobility and field dependent conductivity, by which the effect of fillers on charge transport manners could be estimated. In addition, thermal conductivity test, scanning electron microscopy and differential scanning calorimetry had been employed to assist the analysis of the filler effect. Test results indicated that the crystal structure of LDPE was changed by the doping of the fillers. With the increase of the micro-and nano-filler content, the trap depth tended to be deeper firstly then became shallower. Both band and hopping transport of charge occurred in the composite, and the carrier mobility was dependent upon the filler content. It is suggested that the addition of the nano-sized SiO 2 and the microsized h-BN particles has an effect to inhibit the charge transport, where a synergistic effect among the nano-sized and the micro-sized particles is expected to modify charge trapping and de-trapping behavior.

This paper briefly explains the food safety problems related to pesticide residues and introduces microfluidics technology as a pesticide residue detection method. Three mainstream microfluidic detection devices are detailed: one driven by liquid surface tension, one by motor siphon drive, and one by centrifugal force. The advantages and disadvantages of each are considered in an analysis of future trends in microfluidic technology for pesticide detection.

Chemical corrosion and gamma-ray irradiation appeared with the loss of coolant accident may seriously threaten the safe operation of a nuclear power plant, where epoxy resin (ER)-based materials are widely used. It is urgent to study the effects of the corrosion and the irradiation on the electrical performance in an ER-based nanocomposite. In this work, ER/Al 2 O 3 nanocomposite samples with 0, 1, 3, 5-wt% nano Al 2 O 3 filler content were prepared at the thickness of 2 mm, and the total gamma irradiation dose was 0, 500, and 1000 kGy. The samples were chemically corroded in a boric acid solution (pH = 4.7) and a trisodium phosphate alkaline solution (pH = 11) at 60°C and 100°C for 48 h. Charge transport behaviour in the samples was derived from the surface potential decay method. In addition, the sample structures were characterised to analyse the corrosion mechanism in the solutions. The results indicated that the depth and the density of the trap showed a temperature-dependent manner associated with the corrosion. With the addition of appropriate content of the filler, the trap centre was deepened and the carrier mobility was limited even after the corrosion. It is found that the appearance of hydroxyl and carboxyl groups during corrosion, the interaction between the nanoparticle and the matrix and the crosslinking reaction caused by the irradiation are responsible for the variation in charge transport behaviour.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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