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Hu Y.,Hong Kong Polytechnic University | Hu Y.,Hubei University | Gu H.,Hubei University | Chen W.,Hong Kong Polytechnic University | And 2 more authors.
Materials Chemistry and Physics | Year: 2010

In this work, we report the preparation of lead titanate (PT) nanoceramics (with an average grain size of ∼200 nm in diameter) by using hydrothermal PT nanoparticles as start materials and characterized the dielectric and ferroelectric properties. The dielectric constant of the ceramic was found to be ∼180 (at 1 kHz) at room temperature and reached a maximum value of 8330 at ∼490 °C, suggesting that the Curie temperature of the nanoceramics is consistent with the known value of PT crystals. Ferroelectric domains and hysteresis loops were obtained through piezoelectric force microscopy measurements, which provide direct and clear evidence for the ferroelectricity in the nanoceramic samples. © 2010 Elsevier B.V. All rights reserved. Source


Shen Y.,Nanchang University | Fu J.,Nanchang University | Yu G.,Key Laboratory of Acoustic and Photonic Materials and Devices | Yu G.,Wuhan University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2011

One-dimensional chirped photonic crystals composed of alternating dielectric slabs are proposed to realize rainbow trapping. We theoretically and numerically demonstrate that not only significantly reduced group velocity can be achieved in the proposed chirped structures, but different wavelengths can be localized in different spatial positions, indicating trapped rainbow. Our results imply a feasible way to slow or even trap light in simple systems, which can be used for optical buffer, memory, data processor and filter, sorter, etc. © 2011 Elsevier B.V. All rights reserved. Source


Wang Y.-Q.,Hubei University | Wang Y.-Q.,Hubei University of Education | Jiang X.-D.,Hubei University | Pan C.-X.,Hubei University | Pan C.-X.,Key Laboratory of Acoustic and Photonic Materials and Devices
Jinshu Rechuli/Heat Treatment of Metals | Year: 2010

This paper introduces a novel approach for growing a TiO2 photocatalytic film by using a micro-arc oxidation ( MAO) technique. The experimental process, growth mechanism, influencing factors and relationship between microstructure and property of the film were reviewed. It is proposed that the TiO2 film with semiconductor compound, metal and non-metal doping during micro-arc oxidation can effectively improve the photochemical catalysis property. Source


Yang H.,Key Laboratory of Acoustic and Photonic Materials and Devices | Pan C.,Key Laboratory of Acoustic and Photonic Materials and Devices | Pan C.,Wuhan University
Journal of Alloys and Compounds | Year: 2010

This work describes the diameter-controlled growth of the TiO2 nanotube arrays by anodization of Ti foils in the ethylene glycol/HF electrolytes with variant fluoride concentration under a constant applied voltage (30 V). The results reveal synthesis of TiO2 arrays of nanotubes with diameters ranging from 20 to 41 nm when fluoride concentration varied from 0.1 to 0.5 M in the electrolytes. The influence of the fluoride concentration on the diameter and the wall thickness of the TiO2 nanotubes was discussed. The photocurrent response experiments indicate that the TiO2 arrays of nanotubes with diameter of 20 nm had the superior photoelectric property. © 2009 Elsevier B.V. All rights reserved. Source


Zhang J.,Key Laboratory of Acoustic and Photonic Materials and Devices | Pan C.,Key Laboratory of Acoustic and Photonic Materials and Devices | Pan C.,Wuhan University
Journal of Alloys and Compounds | Year: 2010

A novel process is introduced for controlling diameter of carbon nanofibers by changing electric field in a chemical vapor deposition system. It was found that an increase in electric field produced a smaller diameter and narrower diameter distribution of carbon nanofibers, that is, the carbon nanofiber diameter varied in series of 19.2 ± 8.6, 13.8 ± 4.7, and 8.0 ± 2.4 nm corresponding to the electric field of 0, 25,000, and 50,000 V/m, respectively. The theoretical calculation reveals that the mechanism for this change is because Ni catalyst particles become liquid at the reaction temperature and the diameter of the Ni catalyst becomes smaller under the electric field. © 2010 Elsevier B.V. All rights reserved. Source

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