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Shui-Jinn Wang Shiue-Lung Chen Kai-Ming Uang Wei-Chi Lee Tron-Min Chen Chao-Hsuing Chen Bor-wen Liou 《Photonics Technology Letters, IEEE》2006,18(10):1146-1148
In this study, the performance of vertical-structured high-power GaN-based light-emitting diodes (VM-LEDs) with a transparent and low-resistant indium-zinc oxide (IZO) film as a current spreading layer (CSL) was investigated. Nickel electroplating and patterned laser liftoff techniques were employed for the transfer of sapphire substrate to nickel substrate. The novel IZO CSL atop n-side-up VM-LEDs offering benefits of superior current spreading ability, larger extraction efficiency, and lower forward voltage drop was demonstrated. As compared to the regular LED without IZO CSL, the use of an IZO CSL with an optimum thickness of around 300 nm leads to an increase in light output power by 97.1 (67.8)% and a decrease in forward voltage drop by 4.9 (15.5)% under an injection current of 350 (800) mA. 相似文献
13.
Posada J.F. Liou J.J. Miller R.N. 《IEEE transactions on instrumentation and measurement》1991,40(5):836-841
Population growth results in an increasing demand on water supply. Usually, growers determine how much water is needed to irrigate their fields on the basis of the amount of time elapsed since the last irrigation cycle. A soil moisture sensor enables the users (or an automated irrigation system) to monitor the relative soil moisture constantly at many different locations throughout the field in order to schedule irrigation cycles more precisely. An automated data acquisition system for measuring the characteristics of a soil moisture sensor under various moisture conditions is presented. Based on the measurement data, an empirical model for the soil moisture sensor is also developed. A comparison of the model and experimental data is included 相似文献
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The pitting behaviour of type 321 stainless steel in sulfide-containing chloride aqueous environments was studied using cyclic potentiodynamic polarization. A well-established correlation between H2S and Na2S2O3 in the study of corrosion was applied, that is, H2S was simulated by Na2S2O3. The major factors affecting the pitting corrosion of type 321 stainless steel are the Cl- concentration, solution pH and temperature. The results clearly indicate that both Epit and E
pp decrease with increasing Cl- concentration and temperature, while I
pass is more sensitive to temperature variation. E
pit decreased with decreasing pH in the range 2 < pH < 7.5. The surface morphology and chemistry of the corroded type 321 stainless steel resulting from anodic polarization in 0.01 M S2O
3
2-
-containing Cl- solution were analysed by XRD, SEM and EPMA. A higher concentration of sulfur was found in the pits, and the dark surface film was mainly composed of FeS and -Fe2O3. The results describe the pitting behaviour of type 321 stainless steel in sulfide-containing Cl- aqueous environments. 相似文献
16.
S.‐P. Rwei A.‐Y. Liu G.‐S. Liou K.‐C. Cheng W. Guo 《Polymer Engineering and Science》2004,44(2):376-387
This study investigates the curing kinetics, thermal properties and decomposition kinetics of cresol novolac epoxy (CNE) with two curing agents, 2‐(6‐oxido‐6H dibenz(c,e)(1,2) oxaphosphorin‐6‐yl)‐1,4‐benzenediol (ODOPN), and phenol novolac (PN). In comparison with the conventional PN system, introducing ODOPN, a phosphorus‐containing bulky pendant group, into CNE increases Tg by 33°C, char yield from 30% to 38%, and LOI from 22 to 31. The DSC curing study reveals that the Ea of the CNE/ODOPN epoxy can be obtained by Kissinger's method. The resulting Ea values indicate that the catalytic effect of EMI is insignificant on CNE/ODOPN but is marked on CNE/PN, whose Ea was reduced from 131.5 to 75.6 KJ/mole. This result may be caused by the fact that the symmetric diol attached to the 1 and 4 positions of the naphthalene ring in ODOPN sets up a steadily resonating structure and inhibits the catalytic action. Further investigating the conversion ratio with curing temperature yielded experimental data that agreed closely with Kaiser's model. The orders of the autocatalyzed reaction, m, and the crosslinking reaction, n, are close to 0.5 and 1.0, respectively, independently of the scan rate. Finally, the TGA decomposition study by Ozawa's method demonstrates that the mean Ea declines with the phosphorus content, because the easy decomposition of the phosphorus compound in the initiation stage facilitates the formation of an insulating layer. However, results in this study further reveal an increasing tendency for Ea with decomposition conversion for an ODOPN/PN mixture with the ODOPN content of over 50%, probably because of the retardation of gas diffusion by the insulating layer of phosphorus compound. 相似文献
17.
Polystyrene‐clay nanocomposite (PsCN) materials were synthesized and their properties of crystallinity, thermal behavior, and dielectric characteristics were investigated. A polymerizable cationic surfactant, [2‐(dimethylamino)ethyl]triphenylphonium bromide, was used for the intercalation of montmorillonite (MMT). The organophilic MMT was prepared by Na+‐exchanged MMT and ammonium cations of a cationic surfactant in an aqueous medium. Organophilic styrene monomers were intercalated into the interlayer regions of organophilic clay hosts followed by a free‐radical polymerization. Exfoliation to 2 wt % MMT in the polystyrene (PS) matrix was achieved as revealed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal properties by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were also studied. The dielectric properties of PsCNs in the form of film with clay loading from 1.0 to 5.0 wt % were measured under frequencies of 100 Hz–1 MHz at 25–70°C. A decreased dielectric constant and low dielectric loss were observed for PsCN materials. The dielectric response at low frequency that originated from dipole orientation was suppressed due to the intercalation of clay materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1368–1373, 2004 相似文献
18.
Haythem?GajaEmail author Frank?Liou 《The International Journal of Advanced Manufacturing Technology》2016,86(9-12):2913-2925
Any shortfall in the required depth during milling machining can affect the dimensional accuracy of the part produced and can cause a catastrophic failure to the machine. Corrective remedies to fix the dimensions inaccuracy will increase the machining time and costs. In this work, a depth-of-cut monitoring system was proposed to detect depth of cut in real time using an acoustic emission sensor and prediction model. The characteristics of the sensor signal obtained in machining processes can be complex in terms of both nonlinearity and nonstationarity. To overcome this complexity, a regression model and an artificial neural network model were used to represent the relationship between the acoustic emission signal and the depth of cut. The model was tested under different machining cases and found to be efficient in predicting the depth of cut. 相似文献
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James J.H. Liou Jolanta Tamošaitienė Edmundas K. Zavadskas Gwo-Hshiung Tzeng 《国际生产研究杂志》2016,54(1):114-134
Greening the supply chain is an increasingly important concern for many business enterprises and a challenge for logistics management. Critical functions within green supply chain management are internal improvements and selection of green suppliers. This study proposes a novel, hybrid model that addresses dependent relationships between various criteria and the vague information coming from decision-makers. The Decision-making Trial and Evaluation Laboratory (DEMATEL) technique structures the relationships among criteria, thereby constructing an influential network relationship map (INRM). Meanwhile the DEMATEL-based, analytical network process (ANP) method aids in obtaining influential weights of the criteria. Decision-makers may hold diverse opinions and preferences due to incomplete information, differences in knowledge or simply conflicts that are inherent between various departments. This can make it difficult to judge the performance of alternatives. One remedy is to apply a modified COmplex PRoportional ASsessment of alternatives with Grey relations. Next, this is applied to improve each criterion for integration of the performance values obtained in closing the aspiration level from different expert opinions based on INRM. An empirical example using data from a Taiwanese electronics company is provided to demonstrate our proposed method. The results can provide firms with a knowledge-based understanding of the source of some problems, thus reducing the performance gaps and closing the aspiration levels. Finally, there is a discussion on certain managerial implications. 相似文献