Browsing by Author "Huang, Yi-Jen"

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An Error Resilient Multiple Description Video Coder
(2011)
Huang, Yi-Jen
;
Hsiao, Hsu-Feng
;
資訊工程學系
;
Department of Computer Science
The idea of multiple description video coding has been introduced to deal with the issues of bandwidth/path diversity and packet loss due to network congestion and/or error-prone channels which might cause serious quality degradation in video applications such as multimedia streaming and video conferencing services. In this paper, two approaches to description generation are proposed to produce multiple descriptions at higher coding efficiency. One of them is motivated by the multiple description scalar quantizer to reduce the distortion and the other is the coefficient partition in transform domain in order to balance the descriptions better. An estimation mechanism is further proposed to alleviate the drifting problem due to description fluctuation by synchronizing the reference frames at the encoder and the decoder as much as possible. The experiments show that the proposed methods offer substantial improvement at the event of description loss.
Artificial Synthesis of Platelet-Like Kassite and Its Transformation to CaTiO(3)
(2010-03-01)
Huang, Yi-Jen
;
Tsai, Min-Chiao
;
Chiu, Hsin-Tien
;
Sheu, Hwo-Shuenn
;
Lee, Chi-Young
Platelet-like kassite, a rare mineral CaTi(2)O(4)(OH)(2), wits synthesized by a wet chemical route using Ca(OH)(2) and TiO(2) as reagents in base Solution. The microstructure of the obtained kassite examined by synchrotron radiation and Rietveld refinement are hexagonal (P312) with a = b = 0.52451(2) and c = 0.47844(3) nm. This cell is slightly different from JCPDS No. 88-1722. At heating above 500 degrees C, the layered crystalline kassite rearranges to form disk-like CaTiO(3) and amorphous TiO(2) by removing H(2)O completely. Furthermore, transmission electron microscopy analysis reveals that the vertical axis of disk-like CaTiO(3) along the [0 (2) over bar1] direction converts from that of [001] orkassite.
Artificial Synthesis of Platelet-Like Kassite and Its Transformation to CaTiO3
(2010-03-01)
Huang, Yi-Jen
;
Tsai, Min-Chiao
;
Chiu, Hsin-Tien
;
Sheu, Hwo-Shuenn
;
Lee, Chi-Young
Platelet-like kassite, a rare mineral CaTi2O4(OH)(2), wits synthesized by a wet chemical route using Ca(OH)(2) and TiO2 as reagents in base Solution. The microstructure of the obtained kassite examined by synchrotron radiation and Rietveld refinement are hexagonal (P312) with a = b = 0.52451(2) and c = 0.47844(3) nm. This cell is slightly different from JCPDS No. 88-1722. At heating above 500 degrees C, the layered crystalline kassite rearranges to form disk-like CaTiO3 and amorphous TiO2 by removing H2O completely. Furthermore, transmission electron microscopy analysis reveals that the vertical axis of disk-like CaTiO3 along the [0 (2) over bar1] direction converts from that of [001] orkassite.
Growth of CaTiO(3) dendrites and rectangular prisms through a wet chemical method
(2009-01-01)
Huang, Yi-Jen
;
Chiu, Hsin-Tien
;
Lee, Chi-Young
;
應用化學系
;
Department of Applied Chemistry
Dendrites and rectangular prisms of orthorhombic CaTiO(3) were synthesized massively by reacting titanium tetraisopropoxide with Ca(OH)(2) in basic solutions at 120 degrees C. Dendrites were formed in dilute base solution with moderate stirring while rectangular prisms were formed in concentrated base solution or with vigorous stirring. The 3-D hierarchical dendrites are constructed by a main branch, from which two side branches grow 48 degrees to the trunk. The growth directions of the branches were identified to be {102} and {012). On the other hand, the CaTiO(3) rectangular prisms have {110}, and {001} facets and a longitudinal direction along the normal vector of the {001} planes. The formation of the two distinct morphologies results from different growth behavior. Under non-equilibrium conditions, interface kinetics markedly affects the reaction, resulting from pressure field, heat flow, and crystal orientation, which leads to the formation of complex morphology dendrite. Under equilibrium conditions, thermodynamics dominates the reaction, resulting in exposing of the most stable plane, which leads to the formation of rectangular prisms.
Growth of CaTiO3 dendrites and rectangular prisms through a wet chemical method
(2009-01-01)
Huang, Yi-Jen
;
Chiu, Hsin-Tien
;
Lee, Chi-Young
;
應用化學系
;
Department of Applied Chemistry
Dendrites and rectangular prisms of orthorhombic CaTiO3 were synthesized massively by reacting titanium tetraisopropoxide with Ca(OH)(2) in basic solutions at 120 degrees C. Dendrites were formed in dilute base solution with moderate stirring while rectangular prisms were formed in concentrated base solution or with vigorous stirring. The 3-D hierarchical dendrites are constructed by a main branch, from which two side branches grow 48 degrees to the trunk. The growth directions of the branches were identified to be {102} and {012). On the other hand, the CaTiO3 rectangular prisms have {110}, and {001} facets and a longitudinal direction along the normal vector of the {001} planes. The formation of the two distinct morphologies results from different growth behavior. Under non-equilibrium conditions, interface kinetics markedly affects the reaction, resulting from pressure field, heat flow, and crystal orientation, which leads to the formation of complex morphology dendrite. Under equilibrium conditions, thermodynamics dominates the reaction, resulting in exposing of the most stable plane, which leads to the formation of rectangular prisms.
Optical second harmonic generation from the twin boundary of ZnO thin films grown on silicon
(2008-03-03)
Lo, Kuang-Yao
;
Lo, Shih-Chieh
;
Yu, Chang-Feng
;
Tite, Teddy
;
Huang, Jung-Y.
The symmetry of the twin boundaries of ZnO epitaxial film was detected with reflective second harmonic generation (RSHG). The twin boundaries exhibit mirror symmetry with a polar configuration across the boundary plane and yield a nonvanishing polar contribution to RSHG. The nonvanishing second-order susceptibility supports the notion that the measured RSHG originates from the planar defect, which depends on the residual stress in the thin film. We analyzed our RSHG result by correlating the macroscopic data from optic probe with the microscopic data from tunneling electron microscope.
Simple chemical preparation of perovskite-based materials using alkali treatment
(2012)
Chen, Po-Chin
;
Tsai, Min-Chiao
;
Huang, Yi-Jen
;
Chiu, Hsin-Tien
;
Lee, Chi-Young
In this work, a simple alkali treatment process was introduced to synthesize ABO(3) perovskite related materials: CaTiO3 (CTO), SrTiO3 (STO), BaTiO3 (BTO) and BaxSr1-xTiO3 (BST). The perovskite materials, synthesized by using stoichiometric amounts of corresponding alkaline solutions Ba(OH)(2), Sr(OH)(2), Ca(OH)(2) and powdered TiO2, are pure phase and well-crystallized. The obtained powders are round, round-edged cubes and cubes with sharp edges for BaTiO3, SrTiO3 and CaTiO3 respectively. What's more, the Ba content (x) in BST can be directly and precisely modified to be any value between one and zero. And, the morphology of SrTiO3 can be manipulated by altering the reaction time. As time is prolonged, the morphology of the product changes from round to round-edged cubes to sharp-edged cubes. In the future, materials with such specific microstructure and morphologies may be used in electro-optical and photocatalytic applications.
SrTiO3/TiO2 Hybridstructure as Photoanode in Dye-Sensitized Solar Cell
(2013-12-01)
Wang, Yu-Shiuan
;
Chen, Ting-Ting
;
Huang, Yi-Jen
;
Huang, Tzu-Ping
;
Lee, Yin-Yu
In dye-sensitized solar cells (DSSCs), the charge recombination at the TiO2/dye/electrolyte interface greatly influences the photoelectron conversion efficiency. Hybrid semiconductor materials with matched band potentials are designed to reduce the charge recombination. In this study, SrTiO3/TiO2 hybridstructure was synthesized by using TiO2 nanoparticles as template in a hydrothermal, showing a negative shift in the flat band potential. The DSSC with the SrTiO3/TiO2 anode exhibits an increased photovoltage and a reduced photocurrent. The suppression of charge recombination at the TiO2/dye/electrolyte interface was observed in the electrochemical impedance spectroscopy, causing an improvement in the photovoltage. However, the SrTiO3/TiO2 system shows an obstructed electrons injection from the dye to SrTiO3/TiO2, limiting the photocurrent performance. The photoelectrochemical properties of the SrTiO3/TiO2 system are discussed in detail herein.