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Thermal Model Based Power-Generated Prediction by Using Meteorological Data in BIPV System
(2011-01-01)
Huang, C. Y.
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Chen, H. J.
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Chan, C. C.
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Chou, C. P.
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Chiang, C. M.
Building integrated photovoltaic is an art and trend using PV module to replace building material on the outer wall. The semi-transparent c-Si PV module is installed to replace the tiled roof in this study. PV power generation prediction is follow with module performance, installation site and meteorological data. A simple model is created to simulate the power output using PV module thermal model. PV module thermal model is the relation of the module temperature, ambient temperature and solar radiation. In the present study, two parameter linearly regression model is to simulate the power generation in BIPV system. The monthly root-mean-square error (RMSE) is about 4.7%. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC).
Finite difference time domain analysis of 3-D sub-wavelength structured arrays
(2007-01-01)
Ting, C. J.
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Tsai, H. Y.
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Hsu, C. J.
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Chou, C. P.
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機械工程學系
Optimizing the Auto-brazing Process Quality via a Taguchi-Neural Network Approach in the Automotive Industry
(2009)
Lin, H. L.
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Chou, C. P.
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機械工程學系
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Department of Mechanical Engineering
Many parameters affect the quality of the auto-brazing process. It is not easy to obtain optimal parameters of this process. This paper applies an integrated approach using the Taguchi method and a neural network (NN) to optimize the lap joint quality of air conditioner parts. The proposed approach consists of two phases. First phase executes initial optimization via Taguchi method to construct a database for the NN. In second phase, we use a NN with the Levenberg-Marquardt back-propagation (LMBP) algorithm to provide the nonlinear relationship between factors and the response based on the experimental data. Then, a well-trained network model is applied to obtain the optimal factor settings. The experimental results showed that the tensile strength of specimens of the optimal parameters via the proposed approach is better than apply Taguchi method only.
Effects of sputtering pressure and Al buffer layer thickness on properties of AZO films grown by rf magnetron sputtering
(2010-08-20)
Tseng, C. H.
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Wang, W. H.
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Chang, H. C.
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Chou, C. P.
;
Hsu, C. Y.
Transparent and conductive Al-doped (2 wt.%) zinc oxide (AZO) films were deposited on inexpensive soda-lime glass substrates by using rf magnetron sputtering at room temperature. This study analyzed the effects of argon sputtering pressure, which varied in the range from 0.46 to 2.0 Pa, on the morphological, electrical and optical properties of AZO films. The only (0 0 2) diffraction peak of the film were observed at 20 similar to 34.45 degrees, exhibiting that the AZO films had hexagonal ZnO wurtzite structure, and a preferred orientation with the c-axis perpendicular to the substrate. By applying a very thin aluminum buffer layer with the thickness of 2 nm, findings show that the electrical resistivity was 9.46 x 10(-4) Omega-cm, and the average optical transmittance in the visible part of the spectra was approximately 81%. Furthermore, as for 10 nm thick buffer layer, the electrical resistivity was lower, but the transmittance was decreased. (C) 2010 Elsevier Ltd. All rights reserved.
GROWTH OF AZO FILMS ON BUFFER LAYERS BY RF MAGNETRON SPUTTERING
(2010-12-20)
Chen, C. W.
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Tseng, C. H.
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Hsu, C. Y.
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Chou, C. P.
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Hou, K. H.
Al(2)O(3)-doped zinc oxide (in AZO, the Al(2)O(3) contents are approximately 2 wt.%) films have been grown by radio frequency (RF) magnetron sputtering at room temperature under varied sputtering pressures ranging from 3.5-15 mTorr. The electrical resistivity of AZO films is about 2.22 x 10(-3) Omega cm (sheet resistance similar to 89 Omega/square for a thickness similar to 250 nm), and the visible range transmittance is a bout 80% at the argon sputtering pressure of 15 mTorr and a RF power of 100 W. This study analyzes the structural, morphological, electrical and optical properties of AZO thin films grown on soda-lime glass substrate with 2, 5, and 10 nm thick Al buffer layers (and SiO(2) buffer). For the films deposited on the 2 nm thick Al buffer layer, we obtained ac-axis-oriented AZO/Al thin film on glass with the XRD full-width at half maximum (FWHM) of 0.31 and root mean square (RMS) surface roughness of about 3.22 nm. The lowest resistivity of 9.46 x 10(-4) Omega cm (sheet resistance similar to 37.87 Omega/square for a thickness similar to 250 nm) and a high transmittance (80%) were obtained by applying a 2 nm thick Al buffer layer. In contrast, the resistivity was slightly increased by applying the SiO(2) buffer layer.
Structure and properties of GZO thin films grown on ZnO buffer layers
(2011-02-01)
Chu, C. Y.
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Huang, C. H.
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Kao, L. M.
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Chou, C. P.
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Hsu, C. Y.
Thin gallium-doped zinc oxide (in GZO the Ga(2)O(3) contents are approximately 3 wt%) films having different ZnO buffer layers were deposited using radio frequency (rf) magnetron sputtering. The use of a grey-based Taguchi method to determine the processing parameters of ZnO buffer layer deposition has been studied by considering multiple performance characteristics. A Taguchi method with an L(9) orthogonal array, signal-to-noise (S/N) ratio, and analysis of variance (ANOVA) is employed to investigate the performance characteristics in the deposition operations. The effect and optimization of ZnO buffer deposition parameters (rf power, sputtering pressure, thickness, and annealing) on the structure, morphology, electrical resistivity, and optical transmittance of the GZO films are studied. Annealing treatment and reduction in thickness resulted in a decrease in root-mean-square (RMS) surface roughness of the ZnO buffer layer. Using the optimal ZnO buffer layer obtained by the application of the grey-based Taguchi method, the electrical resistivity of GZO films was decreased from 2.94 x 10(-3) to 9.44 x 10(-4) Omega cm and the optical transmittance in the visible region was slightly increased from 84.81% to 85.82%. (C) 2010 Elsevier Ltd. All rights reserved.
Hot Cracking in AZ31 and AZ61 Magnesium Alloy
(2011-07-01)
Huang, C. J.
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Cheng, C. M.
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Chou, C. P.
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Chen, F. H.
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機械工程學系
This paper examined the impact of the number of thermal cycles and augmented strain on hot cracking in AZ31 and AZ61 magnesium alloy. Statistical analyses were performed. Following observation using a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS) was used for component analysis. Results showed that Al content in magnesium alloy has an effect on hot cracking susceptibility. In addition, the nonequilibrium solidification process produced segregation in Al content, causing higher liquid Mg-alloy rich Al content at grain boundaries, and resulting into liquefied grain boundaries of partially melted zone (PMZ). In summary, under multiple thermal cycles AZ61 produced serious liquation cracking. AZ61 has higher (6 wt%) Al content and produced much liquefied Mg(17)Al(12) at grain boundaries under multiple thermal cycles. The liquefied Mg(17)Al(12) were pulled apart and hot cracks formed at weld metal HAZ due to the augmented strain. Since AZ31 had half the Al content of AZ61, its hot-cracking susceptibility was lower than AZ61. In addition, AZ61 showed longer total crack length (TCL) in one thermal cycle compared to that in three thermal cycles. This phenomenon was possibly due to high-temperature gasification of Al during the welding process, which resulted in lower overall Al content. Consequently, shorter hot cracks exhibited in three thermal cycles. It was found the Al content of AZ31 and AZ61 can be used to assess the hot-cracking susceptibility.
Characterization of Hot Cracking Due to Welding of High-Strength Aluminum Alloys
(2012)
Chang, C. C.
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Chen, C. L.
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Wen, J. Y.
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Cheng, C. M.
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Chou, C. P.
The "Spot-Varestraint Test'' was applied to assess the sensitivity of three aluminum alloys-A2024-T351, A2219-T87, and A7050-T6 to hot cracking from welding. The results indicate that the number of cracks increases with increasing augmented strain. This phenomenon occurs in both the fusion and the heat-affected zones. The number of thermal cycles also has a significant influence on the heat-affected zone; the number of hot cracks increases, especially in the heat-affected zone of the metal weld, with increasing number of thermal cycles. The compositions of these three alloys show that A2024 and A7050 have similar tendencies to be subject to hot cracking, greater than A2219. With increasing number of thermal cycles, the hot cracks show the same tendency, A2024 > A7050 > 2219.
Influence of oxygen flow rate on photocatalytic TiO2 films deposited by rf magnetron sputtering
(2012-02-01)
Chiou, A. H.
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Kuo, C. G.
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Huang, C. H.
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Wu, W. F.
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Chou, C. P.
Titanium dioxide (TiO2) thin films having anatase (1 0 1) crystal structure were prepared on non-alkali glass substrates by rf (13.56 MHz) magnetron sputtering using a TiO2 ceramic target under various oxygen partial pressures. At a fixed substrate temperature of 400 A degrees C and total gas pressure of 1 Pa after 3 h deposition. Effects of oxygen partial pressure on the structural, surface morphology, and photocatalytic activities of the TiO2 thin films were investigated. We performed both photoinduced decomposition of methylene blue (MB) and photoinduced hydrophilicity under UV light illumination. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO2 thin films. The results showed that when the [O-2/(Ar + O-2)] flow rate increased to 50%, the photoinduced decomposition of MB and photoinduced hydrophilicity were enhanced. The water contact angle after 9 min UV illumination was approximately 4.5A degrees, and the methylene blue (MB) solution decomposition from 12 down to 3.34 mu mol/L for 240 min UV irradiation.
The Influence of Aluminum Content of AZ61 and AZ80 Magnesium Alloys on Hot Cracking
(2011)
Huang, C. J.
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Cheng, C. M.
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Chou, C. P.
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機械工程學系
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Department of Mechanical Engineering
This study aims to investigate how aluminum content in magnesium alloys AZ61 and AZ80 impacts the hot cracking susceptibility of magnesium alloys. Differences in aluminum content are known to influence the total crack length of hot cracking. Magnesium alloy AZ61's total crack length was the longest in one thermal cycle, while AZ80's total crack length increased as the number of thermal cycles increased. The most significant difference between AZ61 and AZ80 was the hot crack at the heat-affected zone (HAZ). As the number of heat inputs increased, the grain would coarsen in the HAZ and precipitation started, which resulted in the accumulation of hot cracks at weld metal HAZ (W. M. HAZ). During the solidification of AZ80, which has higher aluminum content, the segregation of aluminum at the grain boundary caused Mg17Al12 to liquefy, increasing the length of hot cracks. Augmented strain caused miniature cracks between Mg17Al12 and grains. Therefore, aluminum content and augmented strain were found causes of hot cracking susceptibility in magnesium alloys.

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