Yu-Lin Kuo

A study of parameter setting and characterization of visible-light driven nitrogen-modified commercial TiO2 photocatalysts.

An optimal condition applied to the Taguchi method with an L(9) orthogonal array for preparing a visible-light driven nitrogen-modified TiO(2) (N-TiO(2)) photocatalyst by a simple hydrolysis method has been examined for material characteristics and a photodecolorization test of methyl blue (MB) under various visible light source (fluorescent and blue LED lamps) irradiations. Results of the material characterization showed that the absorption of prepared N-TiO(2) powder exhibited a significant extension into visible light regimes with an optical bandgap (Eg) of around 2.96 eV, which subsequently improved the visible-light photocatalytic activity of N-TiO(2) samples. The superior photocatalytic properties, the pseudo first-order reaction rate constants (k) and photodecolorization efficiency (η%) of a N-TiO(2) photocatalyst during the photodecolorization test of methyl blue (MB) under two different visible light irradiations were very evident compared to those for pure TiO(2). For photodecolorization of practical dyeing from the waste water from the dyeing and finishing industry, a higher photodecolorization efficiency of N-TiO(2) powder toward Direct blue-86 (DB-86) (Direct Fast Turquoise Blue GL) dye was also achieved.

Mineralization of reactive Black 5 in aqueous solution by ozone/H2O2 in the presence of a magnetic catalyst

Particles are often too small to be separated from a reaction system and recycled, especially in wastewater treatment via a catalytic ozonation process. Thus, the objective of this study was to prepare a magnetic catalyst (SiO(2)/Fe(3)O(4)) that can be recycled by using an external magnetic field. The effects of the characteristics of the magnetic catalyst, pH values, catalyst dosage, and initial concentration of Reactive Black 5 (RB5) on mineralization efficiency of the magnetic catalyst/H(2)O(2)/O(3) process were also investigated. The mineralization efficiency of RB5 under various conditions followed the sequence: SiO(2)/Fe(3)O(4)/H(2)O(2)/O(3)>SiO(2)/Fe(3)O(4)/O(3)>Fe(3)O(4)/O(3) approximately H(2)O(2)/O(3)>O(3)>SiO(2)/Fe(3)O(4)/H(2)O(2). Given the results of our reuse and recovery experiments, the magnetic catalyst shows considerable promise for use in water treatment.

Diffusion barrier properties of sputtered TaNx between Cu and Si using TaN as the target

TaNx films sputtered from a TaN target were used as diffusion barriers between Cu thin films and Si substrates. Material characteristics of TaNx films and metallurgical reactions of Cu/TaN x /Si systems annealed in the temperature range 400–900 ◦ C for 60 min were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, cross-sectional transmission electron microscopy, and sheet resistance measurements. We found that the deposition rate decreased with increasing bias. TaN, -Ta, and Ta2N phases appeared and/or coexisted in the films at specific biases. A step change in N/Ta ratio was observed whenever a bias was applied to the substrate. After depositing a copper overlayer, we observed that the variation percentage of sheet resistance for Cu (70 nm)/TaN x (25 nm, x = 0.37 and 0.81)/Si systems stayed at a constant value after annealing up to 700 ◦ C for 60 min; however, the sheet resistance increased dramatically after annealing above 700 and 800 ◦ C for Cu/TaN0.37/Si and Cu/TaN0.81/Si systems, respectively. At that point, the interface was seriously deteriorated and formation of Cu3Si was also observed.

Characteristics of sputtered TaBx thin films as diffusion barriers between copper and silicon

Abstract Ta–B–N thin films were prepared by rf-magnetron sputtering from a TaB2 target in N2/Ar reactive gas mixtures and then used as diffusion barriers between Cu and Si substrates. In order to investigate the performance of Cu/Ta–B–N/Si contact systems, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), four-point probe measurement, scanning electron microscopy (SEM), cross-sectional transmission electron microscopy (XTEM), and Auger electron spectroscopy (AES) depth profile were used. Results of this study indicate that the barrier characteristics are significantly affected by the nitrogen content. In addition, the failure mechanism for the Cu/Ta–B–N/Si contact systems is also discussed herein.

Diffusion of Copper in Titanium Zirconium Nitride Thin Films

Honeywell Electronic Materials Star Center, Sunnyvale, California, USAThe diffusion coefficient of Cu in~Ti, Zr!N was measured by X-ray diffraction~XRD! and four-point probe~FPP! analyses afterannealing Cu/~Ti, Zr!N/Si multilayered samples in the temperature range of 500-900°C. Cu diffusion in~Ti, Zr!N had componentsfrom both the grain boundaries and the lattice based on diffusional analysis. This study suggests that for the measurement of thediffusion coefficient of Cu, FPP analysis is more precise and sensitive than XRD analysis. Additionally,~Ti, Zr!N has better Cudiffusion barrier properties than those of TaN and TiN.© 2004 The Electrochemical Society. @DOI: 10.1149/1.1644355# All rights reserved.Manuscript received May 1, 2003. Available electronically January 22, 2004.

Application of back-propagation Neural Network Fuzzy Clustering in textile texture automatic recognition system

This study proposed to use wavelet transfer to acquire image hue and value as image features, and use Back-propagation Neural Network Fuzzy Clustering analysis to recognize type of textile texture. Firstly, the RGB color space of original color image is transferred to HSV color space; secondly, wavelet transfer is applied to obtain vertical, horizontal and diagonal images of hue and value, and compute its wavelet energy to take them as texture features of this image. Finally, the back-propagation neural network is adopted to make fuzzy clustering analysis of this image texture feature. As indicated by experimental result, this system can recognize accurately plain weave, twill weave and satin weave textures in woven fabric, single and double textures in knitted fabric, and nonwoven texture in nonwoven fabric. Among 300 test samples in total where there are 50 samples each kind of fabric texture, the general recognition rate amounts to 97.67%. Therefore, this study succeeded in building the automatic computer visual inspection system to recognize textile texture type, which can greatly improve and avoid current low efficiency, non-objective judgment and labor waste due to human inspection.

Use of Spinel Nickel Aluminium Ferrite as Self-Supported Oxygen Carrier for Chemical Looping Hydrogen Generation Process

ABSTRACTChemical looping hydrogen generation (CLHG), as a new technology involved in chemical looping combustion (CLC) process and steam-iron process, has attracted attention for clean energy generation and efficient energy conversion. A systematic investigation of spinel NiFeAlO4 has led to characterization of a well-defined self-supported oxygen carrier which was prepared by solid state reaction. The redox behavior of NiFeAlO4 shows the enhancement on the resistance to agglomeration exceeding previously reported CLC process using similar compositions including Fe2O3, NiO and NiFe2O4 without any inert support. Moreover, the high CO2 conversion and H2 generation by NiFeAlO4 oxygen carrier under a fixed-bed reactor (FxBR) were obtained. The reaction mechanism of NiFeAlO4 subjected to the isothermal stepwise reduction in a sequence of varying durations by XRD was also demonstrated, which provided with a novel function of self-supported and agglomeration-resistant characteristic in the oxygen carrier system.

Preparation of platinum- and silver-incorporated TiO2 coatings in thin-film photoreactor for the photocatalytic decomposition of o-cresol

Platinum-incorporated TiO2 (Pt-TiO2) and silver-incorporated TiO2 (Ag-TiO2) coatings on sapphire tubes of a thin-film photoreactor were prepared using a photoreduction process. Results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the Ag-TiO2 coatings consisted of a mixture of Ag2O, Ag and TiO2 particles, owing to the partial oxidization of silver particles on the TiO2 coatings, while the Pt-TiO2 coating contained a mixture of Pt and TiO2 particles. Diffuse reflectance UV-Vis spectra (DRS) showed that metal particles (Ag or Pt) incorporated into the TiO2 coatings promoted optical absorption in the visible region and made it possible for the coatings to be excited by visible light. Photoluminescence (PL) spectra showed that the PL intensity of the Pt-TiO2 coating was lower than that of the Ag-TiO2 and TiO2 coatings, indicating that the Pt-TiO2 coating had a higher efficiency of charge carrier trapping, immigration and transfer, which subsequently promoted the pseudo-first-order rate constants after the UV/TiO2 process. The Pt-TiO2 coatings for the photocatalytic decomposition of o-cresol under UV light irradiation corresponded to a higher pseudo-first-order rate constant (k) of 0.02 min−1 when compared with the photocatalytic decomposition rates of pure TiO2 coatings (k=0.0062 min−1) and Ag-TiO2 coatings (k=0.01 min−1). The experimental results also indicated that the photodegradation rate of the Pt-TiO2 coating under visible light irradiation was significantly higher than the photodegradation rates of the Ag-TiO2 and pure TiO2 coatings.

Growth of (Ti,Zr)N Films on Si by DC Reactive Sputtering of TiZr in N 2 / Ar Gas Mixtures Effect of Flow Ratio

Titanium zirconium nitride [(Ti,Zr)N] films were prepared on Si substrates by dc reactive magnetron sputtering from a Ti-5 atom % Zr alloy target in N 2 /Ar gas mixtures. Material characteristics of the (Ti,Zr)N films were investigated by X-ray photoelectron spectroscopy, four-point probe, X-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy. According to those results, the deposition rate, chemical composition, crystalline structure, and film resistivity of the deposited films correlate with the N 2 /Ar flow ratio. The microstructure of the (Ti,Zr)N films was an assembly of very small columnar crystallites with a rock-salt (NaCI) structure and an enlarged lattice constant (over pure TiN). A minimum film resistivity of 59.3 μΩ cm was obtained at an N 2 /Ar flow ratio of 2.75, corresponding to near stoichiometric film composition [N/(Ti,Zr) = 0.96] and crystalline structure.

Characteristics of DC Reactively Sputtered (Ti,Zr)N Thin Films as Diffusion Barriers for Cu Metallization

(Ti,Zr)N films were prepared by dc reactive magnetron sputtering from a Ti-5 atom % Zr alloy target in N 2 /Ar gas mixtures and then employed as diffusion barriers between Cu thin films and Si substrates. Material characteristics of the (Ti,Zr)N film were investigated by X-ray photoelectron spectroscopy and cross-sectional transmission electron microscopy (XTEM). The (Ti,Zr)N film microstructure was an assembly of Very small columnar crystallites with a rock-salt (NaCI) structure. Metallurgical reactions of Cu/(Ti,Zr)N 0 . 9 5 /Si, Cu/(Ti,Zr)N 0 . 7 6 /Si, and Cu/TaN 0 . 7 1 /Si were studied by X-ray diffraction and sheet resistance measurements. The variation percentage of sheet resistance for all Cu/barrier/Si systems stayed at a constant value after annealing up to 500°C for 30 min. However, the sheet resistance increased dramatically after annealing above 750°C for Cu/(Ti,Zr)N 0 . 9 5 /Si, and 500°C for both Cu/(Ti,Zr)N 0 . 7 6 /Si and Cu/TaN 0 . 7 1 /Si. For these samples, the interface deteriorated seriously and formationof Cu 3 Si was observed by XTEM. Our results suggest thai the refractory binary metal nitride film, (Ti,Zr)N, can be used as a diffusion barrier for Cu metallization as compared to the well-known TaN film.