Browsing by Issue Date, starting with "2004-03-05"

Now showing 1 - 20 of 70519

Inhibitory effects on phospholipase A2 and antivenin activity of melanin extracted from Thea sinensis Linn
(2004-03-05)
Hung, YC
;
Sava, V
;
Hong, MY
;
Huang, GS
;
材料科學與工程學系奈米科技碩博班
Antivenin activity of melanin extracted from black tea (MEBT) was reported for the first time. The antagonistic effect of MEBT was evaluated for Agkistrodon contortrix laticinctus (broadbanded copperhead), Agkistrodon halys blomhoffii (Japanese mamushi), and Crotalus atrox (western diamondback rattlesnake) snake venoms administered i.p. to ICR mice. MEBT was injected i.p. immediately after the venom administration in dose of 3 mg per mouse in the same place of venom injection. MEBT demonstrated neutralization effect against all venoms tested. The greatest antivenin effect of MEBT was found against Japanese mamushi snake venom. In this case, half the mice died within 2.5 +/- 0.7 h after injection of 0.9 mg/kg of venom. An immediate injection of MEBT substantially reduced the toxic effect of venom and extended time at the 50% level of survival up to 52.3 +/- 2.3 h. The antivenin activity of MEBT is due to chelating of Ca++ and non-specific binding of phospholipase A2. The inhibitory effect of MEBT on phospholipase A2 assessed for different venoms was similar to that obtained with pure enzyme. Low toxicity of MEBT in combination with its antagonistic activity against different venoms may allow effective life-saving treatment against snakebites. Such application of MEBT is important when identification of the snake is impossible or if specific treatment is unavailable. (C) 2004 Elsevier Inc. All rights reserved.
Chaos synchronization and chaos anticontrol of a suspended track with moving loads
(2004-03-05)
Ge, ZM
;
Wu, HW
;
機械工程學系
;
Department of Mechanical Engineering
In this paper, we first study the chaotic synchronization phenomenon of the suspended track with moving load system and then the transient response of chaos synchronization. The Lyapunov exponent is utilized to prove the chaos synchronization, but under certain conditions it is more complicated. Next, we study the synchronization of autonomous and non-autonomous systems. We find that slave systems cannot be synchronized with master system for certain time excitations no matter how large A is. Next, the phase synchronization between them will be studied. An application of chaos synchronization and secure communication is presented. Finally, in order to increase the chaos phenomena, we use anticontrol. Constant torque, periodic torque, periodic impulse signal, time delay function, and adaptive control are used successfully to control the state from order to chaos. (C) 2003 Elsevier Science Ltd. All rights reserved.
Preconditioning multichannel adaptive filtering algorithms using EVD- and SVD-based signal prewhitening and system decoupling
(2004-03-05)
Bai, MR
;
Elliott, SJ
;
機械工程學系
;
Department of Mechanical Engineering
It is well known that the convergence rate of multichannel LMS-based algorithms is limited by the correlation properties of the reference signals and the cross-coupling within the plant dynamics. These factors give rise to excessive eigenvalue spread and slow convergence rate of a gradient descent algorithm. A preconditioning technique is developed in this study for the multichannel LMS algorithm so as to improve its convergence rate. Signal prewhitening and system decoupling are the two key elements of the proposed techniques. Preconditioning filters are first formulated in the frequency domain by using eigenvalue decomposition and singular value decomposition. These filters are then transformed into the time domain with causality taken into account. The preconditioning filters are incorporated into a multichannel LMS algorithm, where the reference signals are prewhitened and the plants are decoupled prior to the adaptation process. Simulations for a two-channel/one listener cross-talk cancellation problem illustrate the effectiveness of the preconditioning technique in improving the convergence rate of the adaptive algorithms. (C) 2003 Elsevier Science Ltd. All rights reserved.
Tunable dual-wavelength linear-cavity fiber laser by using an external injection-seeding scheme
(2004-03-05)
Peng, PC
;
Chi, S
;
光電工程學系
;
Department of Photonics
In this paper, we propose and demonstrate a tunable dual-wavelength fiber laser by using an external injection-seeding scheme with a Fabry-Perot laser diode. The wavelength tuning range of this tunable dual-wavelength fiber laser is 12.6 nm, and the optical side-mode suppression ratio (SMSR) is more than 27 dB. (C) 2004 Wiley Periodicals, Inc.
Effects of tertiary butyl substitution on the charge transporting properties of rubrene-based films
(2004-03-08)
Fong, HH
;
So, SK
;
Sham, WY
;
Lo, CF
;
Wu, YS
The charge transporting properties of rubrene (5,6,11,12-tetraphenylnaphthacene or RB), and a new rubrene-based complex, tetra(t-butyl)-rubrene [2,8-di(t-butyl)-5,11-di[4-(t-butyl)phenyl]-6,12-diphenylnaphthacene or TBRB], were examined in the form of amorphous films as functions of electric field and temperature by means of time-of-flight technique. At room temperature, the hole mobility mu for RB is 7-9 x 10(-3) cm(2) V-1 s(-1) whereas mu for the more bulky TBRB is about 2 x 10(-3) cm(2) V-1 s(-1). The microscopic conduction mechanism in both materials can be modeled by the Gaussian disorder model in which hopping conduction occurs through a manifold of sites with energetic and positional disorder. The energetic disorder in RB and TBRB is almost identical and is about 78 meV in each case, and is mainly controlled by van der Waals interaction. The t-butyl groups in TBRB induce large fluctuations in the spatial separation among TBRB molecules and result in an increase in the positional disorder, and hence a reduction in the hole mobility. (C) 2003 Elsevier B.V. All rights reserved.
Spirobifluorene-linked bisanthracene: An efficient blue emitter with pronounced thermal stability
(2004-03-09)
Shen, WJ
;
Dodda, R
;
Wu, CC
;
Wu, FI
;
Liu, TH
Spiro-FPA, a novel blue emitter, in which two identical anthracene luminophores are linked orthogonally around a spirobifluorene core, has been synthesized and characterized. The introduction of a spiro linkage into the structure of spiro-FPA leads to a reduction in crystallization tendency and an increase in glass transition temperature relative to the monomeric units. In addition, the tetrahedral nature of the carbon atom at the spiro center preserves the optical and electrochemical characteristics of the pristine anthracene units. As demonstrated by AFM measurements, high-quality amorphous films of spiro-FPA with good morphological stability can be prepared by vapor deposition. Organic EL devices constructed using a 1.0-wt % TBP-doped spiro-FPA emitting layer produce bright blue emissions with a high luminescence efficiency of 4.9 cd/A (2.07 lm/W).
赴巴黎參加<詩人之春>活動廖咸,羅智成,唱作俱佳
(2004-03-11)
蔡筱穎
Reactive resonance in a polyatomic reaction
(2004-03-12)
Shiu, W
;
Lin, JJ
;
Liu, KP
;
應用化學系
;
Department of Applied Chemistry
In the course of an extensive investigation aimed at understanding the detailed mechanisms of a prototypical polyatomic reaction, several remarkable observations were uncovered. To interpret these findings, we surmise the existence of a reactive resonance in this polyatomic reaction. The reaction of concern is F+CH4-->HF+CH3, and the abnormal attributes were revealed only near the reaction threshold. The discovery of reactive resonance in a polyatomic reaction is more than just an extension from a typical atom+diatom reaction. As shown here, it holds great promise to disentangle the elusive intramolecular vibrational dynamics of transient collision complex in the critical transition-state region.
Miscibility, specific interactions, and self-assembly behavior of phenolic/polyhedral oligomeric silsesquioxane hybrids
(2004-03-15)
Lee, YJ
;
Kuo, SW
;
Huang, WJ
;
Lee, HY
;
Chang, FC
The miscibility of a phenolic resin with polyhedral oligomeric silsesquioxane (POSS) hybrids and the specific interactions between them were investigated with Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray diffraction (WAXD). An analysis of the morphology and microstructure was performed with polarized optical microscopy and atomic force microscopy (AFM). The interassociation equilibrium constant between the phenolic resin and POSS (38.7) was lower than the self-association equilibrium constant of pure phenolic (52.3) according to the Painter-Coleman association model. This result indicated that POSS was partially miscible with the phenolic resin. A polarized optical microscopy image of a phenolic/POSS hybrid material (20 wt % POSS) indicated that the crystals of POSS were arranged evenly in the phenolic matrix; the self-assembled array of POSS crystals was also confirmed by AFM. This phenomenon was consistent with the FTIR spectroscopy and WAXD analyses. (C) 2004 Wiley Periodicals, Inc.
High-power AlGaInP light-emitting diodes with metal substrates fabricated by wafer bonding
(2004-03-15)
Peng, YCS
;
Wu, YS
;
材料科學與工程學系
;
Department of Materials Science and Engineering
High-power light-emitting diodes (LEDs) fabricated on Cu substrates were investigated in this study. The AlGaInP LED structure was bonded to a Cu substrate by using indium-tin-oxide as the diffusion barrier layer. It was found that Cu-substrate-bonded LED devices could be operated in a much higher injection forward current, 800 mA, which was eight times higher than that used in traditional GaAs-substrate LEDs. The luminous intensity of the Cu-substrate LEDs could reach as high as 1230 mcd, which was three times higher than that of the GaAs-substrate LEDs. (C) 2004 American Institute of Physics.
The influence of oxygen and nitrogen doping on GeSbTe phase-change optical recording media properties
(2004-03-15)
Dimitrov, D
;
Shieh, HPD
;
光電工程學系
;
Department of Photonics
Nitrogen and oxygen doped and co-doped GeSbTe (GST) films for phase-change optical recording are investigated. It is found that the crystallization temperature increased as well as the crystalline microstructure refined by doping. The carrier-to-noise ratio (CNR) and erasability of phase-change optical disks are improved being up to 52 and 35 dB, respectively, by using an appropriate nitrogen doping or co-doping concentration in the recording layer. Optical disks with co-doped recording layer are found to be superior in the recording characteristics then the single doped recording layer disks. (C) 2003 Elsevier B.V. All rights reserved.
Implantable neuromorphic vision chips
(2004-03-18)
Chiang, CT
;
Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The implantable neuromorphic vision chips are analysed and implemented. These proposed analogue integrated circuits are to implement four cell functions of the retina for implant. These retinal cells are photoreceptor cells, horizontal cells, bipolar cells, and ganglion cells. All simulation results are successfully verified and consistent with researches on biological retinas.
僑生週系列展覽活動 ─ 寰宇風情
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
時間：93年3月1 7、18、19 日（三、四、五）內容：今年的展覽的主軸是「寰宇風情」旅遊資訊展
本校與馬偕醫院進行研究交流研討會
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
時間：93年3月13日（六）地點：馬偕紀念醫院台北院區福音樓第一講堂
本校師長赴台中榮民總醫院進行訪問暨座談
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
時間：93 年 3 月 9 日（二）行程：15:30-17:30 與陽明實習學生座談、17:00-19:00 與陽明校友晚餐及座談
本校接受陽明牙醫校友會捐贈新臺幣一佰萬元
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
時間：93 年 3 月 10 日（三）捐贈地點：陽明牙醫館 105 視聽教室捐贈項目：陽明牙醫館 110 室、 201 室、 203 室、 304 室整建工程
生化所專題演講系列
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
時間： 93 年 3 月 29 日 ( 一 ) 10:30-11:30 地點：生化所 501 教室
人生的選擇－談留學英倫
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
交通大學就業與升學輔導組訂於 3/22(一)晚上6:30，舉辦台灣聯大四校視訊演講，講題為「人生的選擇－談留學英倫」.....
醫學系演講公告
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
時間： 93年3月24日(三)中午12:00-13:30 地點：護理館一樓傳醫所 118室
基因體研究中心分子細胞遺傳學技術研習會
(國立陽明大學, 2004-03-20)
陽明電子報編輯小組
線上報名截止日期 : 2004 年 3 月 23 日 (額滿為止) 活動日期 : 2004 年 3 月 29 - 30 日