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Li J.,Shanghai Second Polytechnic University
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology

The glass fibre (GF)-reinforced polyimide (PI) composites filled with graphite powders were fabricated by means of hot press moulding technique. The friction and wear properties of the resulting composites sliding against GCr15 steel were investigated on a model ring-on-block test rig at dry sliding condition. The wear mechanisms were also discussed based on scanning electron microscopic examination of the worn surface of the PI composites and the transfer film formed on the counterpart. With the increasing normal loads, the friction coefficient of the composites decreased under the dry sliding, owing to inconsistent influences of shear strength and real contact areas. Experimental results revealed that the incorporation of graphite significantly improves the wear resistance of the GF-reinforced PI composites. For best combination of friction coefficient and wear rate, the optimal volume content of graphite in the composites appears to be 30 per cent. Source

Feng L.,Tongji University | Yan Y.,Tongji University | Chen Y.,Tongji University | Wang L.,Shanghai Second Polytechnic University
Energy and Environmental Science

Recently, the application of microbial fuel cells (MFCs) with cost-effective and long durable cathodic catalysts to generate electricity sustainably, has drawn much attention. This study investigated the use of nitrogen-doped carbon nanotubes (NCNTs) as the cathodic catalyst for oxygen reduction in MFCs to produce electricity efficiently and durably. The obtained maximum power density was 1600 ± 50 mWm-2, which was higher than the commonly used platinum (Pt) catalyst (Pt/C) (1393 ± 35mWm-2). Also, the drop percentage of power densities with NCNTs was lower than with Pt/C over 25 cycles, indicating that MFCs with NCNTs as the cathodic catalyst could generate electricity more durably than those with Pt/C. Further investigation of the mechanisms revealed that MFCs with the bambooshaped and vertically aligned NCNTs had lower internal resistance and higher cathode potentials. Rotating ring-disk electrode voltammogram, Raman microspectroscopy and X-ray photoelectron spectroscopic analyses suggested that NCNTs possessed a higher electrocatalytic activity for the oxygen reduction reaction (ORR) via a four-electron pathway in neutral pH phosphate buffer solution (PBS). Cyclic voltammograms on NCNTs and Pt/C electrodes before and after a continuous potentiodynamic swept in neutral PBS demonstrated that NCNTs had a better durability for cathodic ORR than Pt/C, which drove MFCs with NCNTs to generate electricity durably. © The Royal Society of Chemistry 2011. Source

Li J.,Shanghai Second Polytechnic University
Polymer - Plastics Technology and Engineering

Silane coupling agent SG-Si900 (SGS) modification and air-oxidation methods were used to improve the interfacial adhesion of the carbon fiber-reinforced polyimide (CF/PI) composite. The interfacial characteristics of the composites reinforced by the carbon fibers treated with different surface modification methods were comparatively investigated. Results showed that both SGS modification and air-oxidation method improved the adhesion between the reinforcement and matrix and SGS modification method was superior to air-oxidation method. For CF/PI composite the optimum interfacial adhesion was obtained at 0.3wt% SGS concentration. The fracture surfaces of samples were investigated by scanning electronic microscopy (SEM) to analyze the effects of different surface treatment methods. © Taylor & Francis Group, LLC. Source

Luo L.,Shanghai Second Polytechnic University
Physics Letters, Section A: General, Atomic and Solid State Physics

Based on the binary Bell polynomials, the bilinear form for the Boiti-Leon-Manna-Pempinelli equation is obtained. The new exact solutions are presented with an arbitrary function in y, and soliton interaction properties are discussed by the graphical analysis. Further, the bilinear Bäcklund transformation is derived by the binary Bell polynomials, and the corresponding Lax pair is obtained by linearizing the bilinear equation. © 2011 Elsevier B.V. All rights reserved. Source

Li J.,Shanghai Second Polytechnic University | Xie H.,Shanghai Second Polytechnic University
Materials Letters

Polypyrrole (PPy) nanowires have been successfully grown on the surface of graphene oxide (GO) nanosheets by using a facile chemical method. The GO/PPy composites exhibit a predominant specific capacitance of 633 F/g at a current density of 1 A/g by charge/discharge analysis, in comparison with 227 F/g for pure PPy. The composites also show superior electrochemical rate capability and cycle stability. The attenuation of the specific capacitance is less than 6% after 1000 charge/discharge processes. The high specific capacitance and good stability of the GO/PPy composites are very promising for applications in electrochemical supercapacitor devices. © 2012 Elsevier B.V. All rights reserved. Source

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