Browsing by Author "Lee, JF"

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A distributed charge storage with GeO2 nanodots
(2004-04-05)
Chang, TC
;
Yan, ST
;
Hsu, CH
;
Tang, MT
;
Lee, JF
In this study, a distributed charge storage with GeO2 nanodots is demonstrated. The mean size and aerial density of the nanodots embedded in SiO2 are estimated to be about 5.5 nm and 4.3x10(11) cm(-2), respectively. The composition of the dots is also confirmed to be GeO2 by x-ray absorption near-edge structure analyses. A significant memory effect is observed through the electrical measurements. Under the low voltage operation of 5 V, the memory window is estimated to similar to0.45 V. Also, a physical model is proposed to demonstrate the charge storage effect through the interfacial traps of GeO2 nanodots. (C) 2004 American Institute of Physics.
Gallium K-edge EXAFS study of GaN : Mg films
(2000)
Pan, YC
;
Wang, SF
;
Lee, WH
;
Lin, WC
;
Shu, CK
Ga K-edge extended X-ray absorption fine structure (EXAFS) measurement was employed to investigate the local structure of GaN:Mg films grown by metalorganic vapor phase epitaxy (MOVPE) with various Cp,Mg dopant flow rates using both in-plane and out-of-plane polarization modes of X-ray. The near edge absorption spectra were found to depend on X-ray polarization strongly for undoped GaN sample and weakly to minutely for heavily Mg-doped and amorphous films. The results indicate Mg incorporation modifies the local structure around the absorber Ga atom and, hence, alters the molecular orbital electron transition of GaN sample. EXAFS analysis showed both vacancy and Mg-interstitial defects contribute to the reduction of coordination numbers along the hexagonal c-axis of GaN:Mg film.
Gallium K-edge x-ray absorption study on Mg-doped GaN
(2001-01-01)
Pan, YC
;
Wang, SF
;
Lee, WH
;
Lee, MC
;
Chen, WK
Ga K-edge x-ray absorption measurements were employed to investigate Mg-doping effects in GaN samples. Strong polarization-dependent x-ray absorption near-edge structures become less pronounced with increasing doping concentration, indicating the formation of a mixing-phase structure of cubic and hexagonal phases. Analysis of the extended x-ray absorption region of the spectra revealed doping-related defects such as vacancies, substitutions, and interstitial occupations. They were formed anisotropically in the crystal c axis direction and its perpendiculars. Disorderliness arising from phase mix and defects is believed to have lowered the Debye temperature of the doped GaN films and caused the destructive interference of the absorption fine-structure oscillation functions. These effects were taken into account for the observed large coordination number reductions in our samples. (C) 2001 American Institute of Physics.
Liquid crystal display industry in Taiwan
(1997)
Liu, SJ
;
Lee, JF
;
交大名義發表
;
科技管理研究所
;
National Chiao Tung University
This paper presents an overview of Taiwan's LCD (Liquid crystal display) industry to illustrate the emergence of competitive advantages of Taiwan's high-tech development. It shows that Taiwanese firms are evolving from manufacturing labour-intensive items of LCDs to more technology intensive TFT LCD. The worldwide LCD demands are growing at a fast pace and Japan leads both in technology and economy of scale. South Korea is next to Japan in terms of market share and production scale, while the USA and European countries are trying to keep up with the world demands. A patent analysis was performed to analyze the technology trend and leading companies. Japan dominates the technology leadership and SHARP plays a key role of TFT technology development. The increase in Labour wages cause Taiwan's industry to be less competitive in the labour-intensive products of TN-LCDs. However, supportive industrial policy, experienced engineers, well-developed IC infrastructures, ample sources of capital investment, and quick response to market needs, serve as the vehicle ibr Taiwan's competitiveness in the international arena of LCD industry.
Robot learning schemes that trade motion accuracy for command simplification
(2000-03-16)
Young, KY
;
Lee, JF
;
Jou, HJ
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This study was inspired by the human motor control system in its ability to accommodate a wide variety of motions. By contrast, the biologically inspired robot learning controller usually encounters huge learning space problems in many practical applications. A hypothesis for the superiority of the human motor control system is that it may have simplified the motion command at the expense of motion accuracy. This tradeoff provides an insight into how fast and simple control can be achieved when a robot task does not demand high accuracy. Two motion command simplification schemes are proposed in this paper based on the equilibrium-point hypothesis for human motion control. Investigation into the tradeoff between motion accuracy and command simplification reported in this paper was conducted using robot manipulators to generate signatures. Signature generation involves fast handwriting, and handwriting is a human skill acquired via practice. Because humans learn how to sign their names after they learn how to write, in the second learning process, they somehow learn to trade motion accuracy for motion speed and command simplicity, since signatures are simplified forms of original handwriting. Experiments are reported that demonstrate the effectiveness of the proposed schemes. (C) 2000 Elsevier Science B.V. All rights reserved.