Key Laboratory of Acoustic and Photonic Materials and Devices

Wuhan, China

Key Laboratory of Acoustic and Photonic Materials and Devices

Wuhan, China
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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.


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.


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.


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.


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.


Zhang K.,Hong Kong Polytechnic University | Zhao L.,Key Laboratory of Acoustic and Photonic Materials and Devices | Guo S.,Key Laboratory of Acoustic and Photonic Materials and Devices | Shi B.,Hong Kong Polytechnic University | And 3 more authors.
Microelectronic Engineering | Year: 2010

A microfluidic system with acoustic wave sensor employing quartz crystal microbalance embedded in the microfluidic channel was developed by soft-lithography technique and characterized by measuring resonance frequency of the sensor under different service conditions. Detections of dynamic fluids in various concentrations and flow rates showed that shift of resonant frequency was observed when there was variation in mass or viscosity of the fluid passing through the microchannels. Through a calibration experiment by monitoring continuous flowing fluids with suspended microparticles, the sensitivity of the system was found to be ∼15 Hz cm2/ng. All these results suggest that the microfluidic system can be employed in in situ monitoring of chemical and biochemical processes involving mass and/or viscosity changes within the microfluidic system. © 2009 Elsevier B.V. All rights reserved.


Chen Z.-Q.,Key Laboratory of Acoustic and Photonic Materials and Devices | Lian C.,Key Laboratory of Acoustic and Photonic Materials and Devices | Zhou D.,Key Laboratory of Acoustic and Photonic Materials and Devices | Xiang Y.,Key Laboratory of Acoustic and Photonic Materials and Devices | And 4 more authors.
Chemical Physics Letters | Year: 2010

Stable and water-soluble ZnCdS:Mn/ZnS core/shell quantum dots (QDs) with quantum yields over 20% have been synthesized via a one-spot aqueous route. Compared with the ZnCdS:Mn cores, the ZnCdS:Mn/ZnS core/shell QDs exhibited approximately 21.0 times stronger photoluminescence due to the greatly decreased nonradiative decay rate. A corresponding synthetic mechanism for such enhancement is discussed in detail. Furthermore, the bandgap energy of the ZnCdS:Mn/ZnS QDs is tuned to a lower level by increasing the Cd concentration in the cores, and the applicability for preparing QD-LEDs with high lumen efficiency is also described. © 2010 Elsevier B.V. All rights reserved.


Wang X.,Key Laboratory of Acoustic and Photonic Materials and Devices | Wang X.,City University of Hong Kong | Mao L.,Key Laboratory of Acoustic and Photonic Materials and Devices | Luo M.,Key Laboratory of Acoustic and Photonic Materials and Devices | And 3 more authors.
Progress in Organic Coatings | Year: 2010

Fullerene-containing epoxy membranes with tunable ultraviolet (UV) optical properties were prepared by adding various amounts of aminated-fullerene derivatives into an epoxy resin/ethylenediamine system. The influences of content and chemical structure (e.g., amine kind and addition degree) of aminated-fullerene on the mechanical, optical and thermal properties of the cured epoxy membranes were investigated systematically. Dynamic mechanical analysis (DMA) indicates that the aminated-fullerene participates in the epoxy curing process and that a star-like crosslinking structure is formed. A higher cross-link density results in a higher glass transition temperature and storage module. The UV-Vis absorbance spectra reveal that the cutoff wavelength λc of the aminated-fullerene/epoxy membranes can be changed over almost the entire UV region simply by varying the fullerene derivative content. The charge-transfer complexes formed between the fullerene derivatives and the epoxy-amine complex may be responsible for the UV light-filtering behaviors. The result of thermogravimertic analyses (TGA) reveals that a higher amount (0.48 wt%) of fullerene derivative obviously leads to the better thermal stability of the cured epoxy membrane. © 2009 Elsevier B.V. All rights reserved.


Mei J.,Key Laboratory of Acoustic and Photonic Materials and Devices | Qiu C.,Key Laboratory of Acoustic and Photonic Materials and Devices | Shi J.,Key Laboratory of Acoustic and Photonic Materials and Devices | Liu Z.,Key Laboratory of Acoustic and Photonic Materials and Devices
Wave Motion | Year: 2010

We theoretically investigate the emission of a point source placed inside a square array of rigid cylinders standing in water. It is shown that a highly directional water wave source can be realized at the band-edge frequency. The angular distribution and signal strength of the emission field depend strongly on the position of the point source relative to the unit cell within which it is placed. Highly directional emission field with half-power angular width of only 8° can be obtained by a simple realization. © 2009 Elsevier B.V. All rights reserved.


Zhao S.,Key Laboratory of Acoustic and Photonic Materials and Devices | Shi Y.,Key Laboratory of Acoustic and Photonic Materials and Devices | Li H.,Key Laboratory of Acoustic and Photonic Materials and Devices | He Q.,Key Laboratory of Acoustic and Photonic Materials and Devices
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

The electrical and optical characteristics of Zn+ ion-implanted Ni/Au ohmic contacts to p-GaN were investigated. After the preparation of Ni/Au electrode on the surface of p-GaN, the metal/p-GaN contact interface was doped by 35 keV Zn+ implantation with fluences of 5 × 1015-5 × 1016 cm-2. Subsequent rapid thermal annealing of the implanted samples were carried in air at 200-400 °C for 5 min. Obvious improvements of the electrode contact characteristics were observed, i.e. the decrease of specific contact resistance and the increase of light transmittance. The lowest specific contact resistance of 5.46 × 10-5 Ω cm2 was achieved by 1 × 1016 cm-2 Zn+ implantation. The transmission enhancement of the electrodes was found as the annealing temperature rises. Together with the morphology and structure analyses of the contacts by scanning and transmission electron microscope, the corresponding mechanism for such an improvement was discussed. © 2010 Elsevier B.V. All rights reserved.

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