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Pan Z.-K.,Guangzhou Quality Supervision and Testing Institute | Lin W.-X.,South China University of Technology | Chu Q.-X.,South China University of Technology
IEEE Transactions on Antennas and Propagation | Year: 2014

A compact single-feed circularly-polarized (CP) wide beam microstrip antenna is proposed for CNSS application. The antenna is designed with a double-layer structure, comprising a circular patch with two rectangular stubs along the diameter direction and a parasitic ring right above it. The resonance frequency and the CP characteristics are mainly controlled by the circular patch and the rectangular stubs, respectively. The vertical HPBW (half power beam width) could be widened by the parasitic ring. Experimental results show that the measured vertical HPBW is approximately 140°and the measured out-of-roundness for the horizontal radiation pattern is only 1.1 dB. Besides, it could maintain good low-profile characteristics. © 2014 IEEE.

Wu W.-Q.,Sun Yat Sen University | Rao H.-S.,Sun Yat Sen University | Feng H.-L.,Sun Yat Sen University | Guo X.-D.,Guangzhou Quality Supervision and Testing Institute | And 2 more authors.
Journal of Power Sources | Year: 2014

The present work establishes a facile process for one-step hydrothermal growth of vertically aligned anatase cactus-like branched TiO2 (CBT) arrays on a transparent conducting oxide (TCO) substrate. Various CBT morphologies are obtained by adjusting the potassium titanium oxide oxalate (PTO) reactant concentration (from 0.05 M to 0.15 M) and this yields a morphologically-controllable branched TiO2 arrays geometry. The CBT arrays consist of a vertically oriented nanowire (NW) or nanosheet (NS) stem and a host of short nanorod (NR) branches. The hierarchical CBT arrays demonstrate their excellent candidatures as photoanodes, which are capable of exhibiting high light-harvesting efficiency in dye-sensitized solar cells (DSSCs). Consequently, DSSCs based on 7 μm long optimized CBT arrays (0.05 M PTO), which are assembled with high density and high aspect-ratio NR branches, exhibit an impressive power conversion efficiency of 6.43% under AM 1.5G one sun illumination. The high performance can be attributed to the prominent light-harvesting efficiency, resulting from larger surface area and superior light-scattering capability. © 2014 Elsevier B.V. All rights reserved.

Hu J.,CAS Guangzhou Institute of Chemistry | Rong T.,Guangzhou Quality Supervision and Testing Institute | Rong M.-Z.,CAS Guangzhou Institute of Chemistry | Zhang M.-Q.,CAS Guangzhou Institute of Chemistry
Acta Polymerica Sinica | Year: 2014

The castor oil was converted into maleic acid ester (i. e. maleated castor oil, MACO) by the reaction with maleic anhydride. Afterwards, the resultant MACO was free-radically copolymerized with reactive diluents (styrene, St) and cured to form foam plastics through conventional foaming technique. By changing MACO/St ratio, mechanical properties and aerobic biodegradability of MACO foams can be easily adjusted. To understand the biodegradation mechanism of the castor oil based plastic foam, various characterization techniques were employed in a systematic way. Compost tests in laboratory soil combined with molecular characterizations demonstrated that the bio-foam has acquired excellent biodegradability. Destruction of the network structure of the castor oil based polymer resulted from fission of ester groups due to attack of microorganisms. The final product of compost tests proved to be carbon dioxide. Inoculation of fungi on the castor oil based polymer further revealed that the vegetable oil acted as carbon source of growth of aspergillus niger. Under the catalysis of lipase, castor oil, MACO and its foam were hydrolyzed to produce fatty acids. The results of different degradation tests matched each other, which not only confirmed biodegradability of MACO plastics, but also preliminarily revealed molecular mechanism of the biodegradation process.

Feng H.-L.,Sun Yat Sen University | Wu W.-Q.,Sun Yat Sen University | Rao H.-S.,Sun Yat Sen University | Wan Q.,Guangzhou Quality Supervision and Testing Institute | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2015

The development of a novel nanoarray photoanode with a heterostructure on a transparent conducting oxide substrate provides a promising scheme to fabricate efficient energy conversion devices. Herein, we successfully synthesize the vertically aligned hierarchical TiO2 nanowire/ZnO nanorod or TiO2 nanowire/ZnO nanosheet hybrid arrays, which are proven to be excellent anode candidates for superior light utilization. Consequently, the quantum-dot-sensitized solar cells based on such hybrid arrays exhibit an impressive power conversion efficiency (PCE) under AM 1.5G one sun illumination with improved short-circuit current density (JSC) and fill factor compared to pristine TiO2 nanowire arrays. Combined with the chemical-bath-deposited Cu2S counter electrode, the eventual PCE can be further optimized to as high as 4.57% for CdS/CdSe co-sensitized quantum dot solar cells. © 2015 American Chemical Society.

Mo M.,South China Normal University | Ye C.,South China Normal University | Lai K.,South China Normal University | Huang Z.,Guangzhou Quality Supervision and Testing Institute | And 5 more authors.
Applied Surface Science | Year: 2013

In this work, gelatin is for the first time utilized to conduct polymer-assisted synthesis of LiNi0.5Mn1.5O4 as the cathode material for 5 V lithium rechargeable batteries. The effect of different amounts of gelatin on structural and morphological properties, electrochemical characterization of the obtained products are investigated by XRD, SEM, charge/discharge testing, cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS), respectively. It's found that with the addition of moderate amount of gelatin, the sample displays a higher degree of crystallinity and phase purity, more uniform shape and monodispersed nanometric size. As a result, electrochemical cycling stability and rate performance are significantly enhanced. CV and EIS measurements further demonstrate that using an optimal amount of gelatin can improve electrochemical performance due to the reversible reaction, faster insertion/extraction of Li ions in the spinel structure and decreased interface independence. © 2013 Elsevier B.V. All rights reserved.

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