Browsing by Author "Wu, Chia-Tien"

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An enzymatic kinetics investigation into the significantly enhanced activity of functionalized gold nanoparticles
(2008)
Wu, Chung-Shu
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Wu, Chia-Tien
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Yang, Yuh-Shyong
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Ko, Fu-Hsiang
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材料科學與工程學系
Kinetic and thermodynamic studies reveal that the property of significantly enhanced catalytic activity with colloidal stability is attributed to an efficacious means of tuning enzyme-substrate association by varying with the rate constants in the presence of functionalized gold nanoparticles.
Application of physical vapor deposition process to modify activated carbon fibers for ozone reduction
(2008-05-01)
Lin, Yu-Chih
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Chang, Chung-Liang
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Lin, Tser-Sheng
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Bai, Hsunling
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Yan, Ming-Gu
This study utilized the activated carbon fiber (ACF) modified with metal catalyst via physical vapor deposition (PVD) process (ACF/PVD) to diminish ozone. Furthermore, the ozone removal efficiency of ACF/PVD was compared with that of original ACF and ACF modified with metal catalyst via impregnation process (ACF/impregnation). In addition to the kinds of coated metal and the inlet ozone concentrations, the effects of the coating thickness and the reaction temperature on ACF/PVD for ozone removal were also examined. The results indicate that the ozone removal efficiency of ACF/PVD is better than that of original ACF and ACF/impregnation. The ozone removal efficiency of different metal-coated ACF/PVD in the superior order is gold (Au), and manganese (Mn). The increase of Au-coated thickness (3 nm to 80 nm) on ACF/PVD will enhance the ozone removal. However, when the Mn-coated thickness on ACF/PVD is larger than 15 rim, the ozone removal efficiency displays a declining trend. Furthermore, a higher reaction temperature will result in a better ozone removal of ACF/PVD and the original ACF.
Broadband and wide angle antireflection of sub-20 nm GaAs nanograss
(2012-06-01)
Ravipati, Srikanth
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Shieh, Jiann
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Ko, Fu-Hsiang
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Yu, Chen-Chieh
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Chen, Hsuen-Li
GaAs nanograss with diameters of less than 20 nm has been fabricated using a simple, one-step, maskless plasma etching-based approach. GaAs nanograss exhibits remarkable broadband antireflection properties, which arise from the graded refractive index between air and the GaAs substrate by the nanograss layer. Moreover, GaAs nanograss shows less sensitivity to transverse electric polarized light and transverse magnetic polarized light over a wide range of incident angles compared to the strong variation in a bare GaAs substrate. These effects show that sub-20 nm GaAs nanograss with lengths of approximately 200 nm has an enhanced absorption of 98-100% when the incident energy is larger than the GaAs bandgap (lambda = 240-873 nm) and an enhanced absorption of 72-98% when the incident energy is less than the bandgap (lambda = 873-2400 nm). Our simple, one-step, and maskless plasma etching method opens a promising approach for the direct implementation of broad omnidirectional antireflective surfaces on solar cells and various optoelectronic devices to improve device performance.
Catalytic Behaviors in Modulating Enzymatic Activity through Different-sized Gold Nanoparticles
(2010)
Wu, Chung-Shu
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Wu, Chia-Tien
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Chen, Chieh
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Huang, Chung-Chih
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Yeh, Yu-Lin
We have demonstrated that gold nanoparticles (AuNPs) can effectively associate with enzyme through spontaneous adsorption to afford supramolecular complexes, resulting in a significant increase of its enzymatic activity. In this work, we embarked on a study of the interactions between the different-sized AuNPs and the substrate through quantifying the kinetic parameters (K(cat) and K(m)). The diversity of size allows us to probe the role of catalytic behaviors in modulating enzymatic activity.
Design of Artificial Hollow Moth-Eye Structures Using Anodic Nanocones for High-Performance Optics
(2010-12-28)
Wu, Chia-Tien
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Lin, Chun-Hung
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Cheng, Chieh
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Wu, Chung-Shu
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Ting, Huai-Chen
We demonstrated an innovative approach for the fabrication of self-organized, hollow-to-solid nanocone arrays, using a decoupling two-step anodization of an Al/Ta interlayer on a substrate. The porosity of the hollow nanostructures was tunable by the deposited thickness of Ta film. We also employed subwavelength nanocone arrays as Moth-eye structures for high-performance antireflection coatings. These oxide nanostructures greatly suppressed reflectance over a large range of wavelengths and angles of incidence and displayed a good mechanical stability. When a corresponding porosity was designed, these nanostructures could be applied to various substrates for an effective antireflection coating. In addition, we were able to customize antireflection coatings for various types of substrates or materials of interest based on the suitable coating of initial Ta thickness.
Self-organized tantalum oxide nanopyramidal arrays for antireflective structure
(2007-04-23)
Wu, Chia-Tien
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Ko, Fu-Hsiang
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Lin, Chun-Hung
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材料科學與工程學系
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材料科學與工程學系奈米科技碩博班
A self-organized tantalum oxide nanopyramidal structure without tedious semiconductor processing is proposed in this letter. Construction of pyramid arrays with a close-packed periodicity of 200 nm and a height of 200 nm was achieved by the anodic alumina template method directly on the substrate. The tantalum oxide nanopyramidal structure was formed as the underlying tantalum film oxidized and localized precisely by the pore of alumina. The reflectance from the spectroscopic measurement suggests that the nanopyramidal array structures have more broadband antireflection (< 2%) than the nanodot arrays and thin film structures. (c) 2007 American Institute of Physics.
Size-modulated catalytic activity of enzyme-nanoparticle conjugates: a combined kinetic and theoretical study
(2011)
Wu, Chung-Shu
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Lee, Cheng-Che
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Wu, Chia-Tien
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Yang, Yuh-Shyong
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Ko, Fu-Hsiang
A series of experiments were performed to systematically analyze the effect of nanoparticle (NP) size on the catalytic behavior of enzyme-NP conjugates, and a shielding model based on diffusion-collision theory was developed to explain the correlation between the size effects and the kinetic responses.
Soft-mold-induced self-construction of polymer patterns under microwave irradiation
(2007-05-07)
Ko, Fu-Hsiang
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Wu, Chia-Tien
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Chen, Mei-Fen
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Chen, Jem-Kun
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Chu, Tieh-Chi
In this study, the authors used a soft-mold-induced self-construction method to fabricate three-dimensional patterns under microwave irradiation for 1 min. The authors estimated the actual pattern growth temperature using a fluorescence probe technique. The temperature at which pattern growth originated was, by necessity, higher than the glass transition temperature of the novolak resist. Electrostatic forces and surface tension effects under the electromagnetic field contributed significantly to the pattern growth, and the use of an antisticking agent allowed easy demolding. (C) 2007 American Institute of Physics.