Browsing by Issue Date, starting with "2004-08-09"

Now showing 1 - 20 of 69676

Defect-enhanced photoconductive response of silicon-implanted borosilicate glass
(2004-08-09)
Lin, GR
;
Lin, CJ
;
Lin, CK
;
光電工程學系
;
Department of Photonics
The E' (delta)-defect-enhanced photoconductivity of a metal-semiconductor-metal photodetector (MSM-PD) made on Si-implanted borosilicate glass (BSO:Si+) substrate is reported. The dark current of as-implanted BSO:Si+ MSM-PD is only 0.1 nA at bias of 70 V. The photocurrent of as-implanted BSO:Si+ MSM-PD illuminated at 488 nm is 0.91 nA, corresponding to photoconductive gain of 9.1 dB. The E' (delta)-defects luminescent at 520 nm are activated after 2 h annealing, which enhances the photocurrent of BSO:Si+ MSM-PD by one order of magnitude. Optimized responsivity, noise equivalent power, and detectivity of BSO:Si+ MSM-PD are 4.0 muA/W, 1.2x10(-9) W/Hz(1/2), and 3.5x10(5) cm Hz(1/2)/W, respectively. The electron paramagnetic resonance and etching-dependent photocurrent analysis corroborate the E' (delta)-defect-related photoconductivity of the BSO:Si+ glass. (C) 2004 American Institute of Physics.
Pumping intensity dependent surface charge accumulation and redshifted microphotoluminescence of silicon-implanted quartz
(2004-08-09)
Lin, GR
;
Yu, KC
;
Lin, CJ
;
Kuo, HC
;
Ou-Yang, MC
The pumping-intensity dependency of nanocrystallite silicon (nc-Si) related microphotoluminescence (mu-PL) from multirecipe Si-implanted quartz is characterized. After annealing at 1100degreesC for 3 h, themu-PL at 724 nm contributed by nc-Si with a diameter of about 4 nm is maximized. By increasing the pumping intensity from 10 kW/cm(2) to 300 kW/cm(2), the mu-PLs of 1 and 3-h-annealed Si-implanted quartz samples are redshifted by <1.2 and 11 nm, respectively. The mu-PL of 3-h-annealed sample further redshifts by 2.5 nm after pumping at 300 kW/cm(2) for h. Such a redshift in PL is attributed to the anomalous quantum Stark effect under strong illumination, which photoionizes the buried nc-Si and initiates an electric field beneath the surface of Si-implanted quartz. The measurement of accumulating charges and voltage drop during illumination primarily elucidate the correlation between redshift in PL and the photoionized nc-Si induced surface electric field. (C) 2004 American Institute of Physics.
Preventive effect of Thea sinensis melanin against acetaminophen-induced hepatic injury in mice
(2004-08-11)
Hung, YC
;
Sava, VM
;
Makan, SY
;
Hong, MY
;
Huang, GS
The preventive effect of Thea sinensis melanin (TSM) against overdoses of N-acetyl-p-aminophenol (NAPAP) was studied on ICR mice. Animals were given 400 mg/kg intraperitoneally (i.p.) of NAPAP, and TSM was injected i.p. in doses 10-40 mg/kg 2 h before intoxication. The protective effects were evidenced by a complete blockage of the NAPAP-induced elevation of plasma alanine aminotransferase (ALT) activity, decreased concentration of thiobarbituric acid reactive substances (TBARS) to the control level, and a partial prevention of reduced glutathione (GSH) depletion in the liver tissue. Preadministration of TSM also caused restoration of superoxide dismutase (SOD) activity and resumed content of coenzymes 09 and Q10. TSM by itself, however, did not affect the hepatic functional parameters, including serum ALT, TBARS, GSH, SOD, or coenzymes Q in the liver. Administration of TSM caused a dose-dependent inhibition of N-nitrosodimethylamine demethylase activity with ED50 of 15.8 mg/kg. Activities of ethoxyresorufin O-dealkylase and pentoxyresorufin O-alkylase isozymes were changed insignificantly. The immune suppressive effect of NAPAP on the in vivo antibody-forming cell responses was demonstrated using ICR-sensitized mice with sheep red blood cells. The joint effect of TSM and NAPAP indicated the capability of TSM to recover immunity of the animals to the level of intact mice. Results obtained demonstrate that TSM preadministration can prevent the multiple toxic effects of NAPAP.
Identification and characterization of the nuclear import and export signals of the mammalian Ste20-like protein kinase 3
(2004-08-13)
Lee, WS
;
Hsu, CY
;
Wang, PL
;
Huang, CYF
;
Chang, CH
Mst3, a human Ste20-like protein kinase, has been recently demonstrated to undergo a caspase-mediated cleavage during apoptosis. The proteolytic cleavage of the C-terminus of Mst3 caused nuclear translocation of its kinase domain. This work provides evidence that Mst3 may contain a bipartite-like nuclear localization sequence (NLS) at the C-terminus of its kinase domain (residues 278-292). The removal of NLS from the kinase domain of Mst3 led to the cytoplasmic accumulation of EGFP-Mst3 (Delta277). The presence of nuclear exporting signals in the Mst3 was also demonstrated by leptomycin B-treatment and serial deletion of the C-terminal regulatory domain of Mst3. A nuclear export signal was also postulated to be in the regions of amino acids 335-386. In conclusion, Mst3 contains both NLS and NES signals, which may cooperate to control the subcellular distribution of Mst3. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Spin and orbital magnetic moments of Fe3O4
(2004-08-13)
Huang, DJ
;
Chang, CF
;
Jeng, HT
;
Guo, GY
;
Lin, HJ
We present measurements of the spin and orbital magnetic moments of Fe3O4 by using SQUID and magnetic circular dichroism in soft x-ray absorption. The measurements show that Fe3O4 has a noninteger spin moment, in contrast to its predicted half-metallic feature. Fe3O4 also exhibits a large unquenched orbital moment. Calculations using the local density approximation including the Hubbard U method and the configuration interaction cluster-model suggest that strong correlations and spin-orbit interaction of the 3d electrons result in the noninteger spin and large orbital moments of Fe3O4.
Fluorescent conjugated polymer films as TNT chemosensors
(2004-08-13)
Chang, CP
;
Chao, CY
;
Huang, JH
;
Li, AK
;
Hsu, CS
Three prototypical light emitting conjugated polymers, two poly(p-phenylene vinylenes) (MEH-PPV and DP10-PPV) and a poly(diphenylacetylene), were examined for chemosensor applications to detect explosive compounds such as 2,4,6-trinitrotoluene (TNT) and 2,4- and 2,6-dinitrotoluene (DNTs). All polymer thin films showed high fluorescence quenching sensitivity towards TNT and DNTs, indicating that a wide range of emissive conjugated polymers are potentially useful chemosensor materials for detecting landmines. The relative sensitivity of fluorescence quenching of the polymers by the analytes has been rationalized in terms of the vapor pressure of the analytes, the solubility parameters of the polymers and the analytes, and the relative energy levels of the polymers. (C) 2004 Elsevier B.V. All rights reserved.
High-power diode-pumped actively Q-switched Nd : YVO4 self-Raman laser: influence of dopant concentration
(2004-08-15)
Chen, YF
;
電子物理學系
;
Department of Electrophysics
Efficient self-Raman frequency conversion from a diode-pumped actively Q-switched Nd:YVO4 laser at 1064 nm to Stokes emission. at 1176 nm is achieved for the first time to the author's knowledge. With a 0.2-at. % Nd:YVO4 crystal, greater than 1.5 W of power at a wavelength of 1176 nm at a repetition rate of 20 kHz was generated with a diode pump power of 10.8 W, corresponding to 4 conversion of 13.9%. Pulse width and peak power were 18 ns and 4.2 kW, respectively. (C) 2004 Optical Society of America.
Significantly enhanced coupling efficiency in 2D photonic crystal waveguides by using cabin-side-like tapered structures at two terminals
(2004-08-15)
Chau, YF
;
Yang, TJ
;
Gu, BY
;
電子物理學系
;
Department of Electrophysics
We report that using a cabin-side-like tapered structure, containing only one pair of defects, can markedly enhance the coupling efficiency at the entrance and exit terminals of planar photonic crystal waveguides (PPCWGs). The PPCWGs are composed of circular dielectric rods set in 2D triangular lattices. By means of simulations, we find that the transmission efficiency reaches up to 90%. Moreover, the suggested structures possess other advantages, such as the shortness of the taper, the ease of fabrication, and its low cost. It is anticipated that the proposed structures might be feasibly be applicable to the integrated optical circuits compatibility.
Permutation polytopes corresponding to strongly supermodular functions
(2004-08-15)
Hwang, FK
;
Lee, JS
;
Rothblum, UG
;
應用數學系
;
Department of Applied Mathematics
Throughout, let p be a positive integer and let Sigma be the set of permutations over {1,....p}. A real-valued function lambda over subsets of {1,... p}, with lambda(theta)=0, defines a mapping of Sigma into R-p where delta is an element of Sigma is mapped into the vector lambda(delta) whose kth coordinate (lambda(delta))(k) is the augmented-value obtained from adding k to the coordinates that precede it, according to the ranking induced by sigma. The permutation polytope corresponding to is then the convex hull of the vectors corresponding to all permutations. We introduce a new class of strongly supermodular functions and for such functions we derive an isomorphic representation for the face-lattices of the corresponding permutation polytope. (C) 2003 Elsevier B.V. All rights reserved.
Electromagnetic resonance in deformed split ring resonators of left-handed meta-materials
(2004-08-15)
Hsu, YJ
;
Huang, YC
;
Lih, JS
;
Chern, JL
;
光電工程學系
Recently, structures called deformed split ring resonators have been proposed to achieve the smallest volume of a unit cell, while retaining negative permeability. With a combination of wire structures, the characteristics of a negative index of refraction, or left-handed meta-materials, can be seen from the transmission spectrum. This electromagnetic resonance, including its orientation tolerance and angular dependence on the incident beam, is explored in detail in the microwave range. (C) 2004 American Institute of Physics.
Soft breakdown enhanced hysteresis effects in ultrathin oxide silicon-on-insulator metal-oxide-semiconductor field effect transistors
(2004-08-15)
Chen, MC
;
Ku, SH
;
Chan, CT
;
Wang, TH
;
電子工程學系及電子研究所
The impact of oxide soft breakdown location on threshold voltage hysteresis in partially depleted silicon-on-insulator metal-oxide-semiconductor field effect transistors with an ultrathin oxide (1.6 nm) is investigated. Two breakdown enhanced hysteresis modes are identified. In a drain-edge breakdown device, excess holes result from band-to-band tunneling flow to the floating body, thus causing threshold voltage variation in drain bias switching. In contrast, in a channel breakdown device, enhanced threshold hysteresis is observed during gate bias switching because of increased valence band electron tunneling. Our findings reveal that soft breakdown enhanced hysteresis effect can be a serious reliability issue in silicon-on-insulator devices with floating body configuration. (C) 2004 American Institute of Physics.
無感測器之三相無刷直流馬達驅動相角自動調整裝置
(2004-08-16)
鄭光耀
;
鄒應嶼
本發明係揭露一種無感測器之三相無刷直流馬達驅動相角自動調整裝置，其係無需透過位置感測器回授，僅需利用量測三相無刷直流馬達任何一相之線電壓與功率級換流器之直流鏈電流作為回授訊號，利用軟體方式即時估算出馬達之旋轉速度及所連接負載之變動情形，並與根據該直流鏈電流所估算出的輸入功率進行比較，透過驅動相角補償器自動調整驅動相角。因此，本發明除了可使馬達運轉效能提高之外，同時亦可達到最佳效率及最大扭矩輸出之無感測驅動控制。
陽明電子報「天涯行旅」徵文及照片
(國立陽明大學, 2004-08-16)
陽明電子報編輯小組
就要Fun暑假了，驛動的心哪，也開始活蹦亂跳起來了吧？陽明電子報規劃新的專欄「天涯行旅」，請所有的陽明師生一起來投稿：無論國內、外的任何景點；文章長短、內容及形式不拘；若無文字僅附照片亦可，但須附圖片說明
Near-infrared femtosecond laser-induced crystallization of amorphous silicon
(2004-08-16)
Shieh, JM
;
Chen, ZH
;
Dai, BT
;
Wang, YC
;
Zaitsev, A
Amorphous silicon (a-Si) was crystallized by femtosecond laser annealing (FLA) using a near-infrared (lambdaapproximate to800 nm) ultrafast Ti:sapphire laser system. The intense ultrashort laser pulses lead to efficient nonlinear photoenergy absorption and the generation of very dense photoexcited plasma in irradiated materials, enabling nonlinear melting on transparent silicon materials. We studied the structural characteristics of recrystallized films and found that FLA assisted by spatial scanning of laser strip spot constitutes superlateral epitaxy that can crystallize a-Si films with largest grains of similar to800 nm, requiring laser fluence as low as similar to45 mJ/cm(2), and low laser shots. Moreover, the optimal annealing conditions are observed with a significant laser-fluence window (similar to30%). (C) 2004 American Institute of Physics.
台灣-菲律賓雙邊合作交流訪問簡報
(國立陽明大學, 2004-08-16)
陽明電子報編輯小組
國科會為了促進與鄰近國家的研究合作，在今年七月廿六日至廿八日組團到菲律賓訪問，藉此推動兩國的學術交流與合作。訪問團包括了工程與醫學兩個工作小組，本校是一所以醫學為主的大學，因此受邀參加這次的國民外交活動
技與藝的結合．武術
(國立陽明大學, 2004-08-16)
江華洲
;
錢玨琄
打卡鐘跳至五點半，行政大樓裡的人影逐漸散去，此時西下的夕陽正伴隨著歸巢的倦鳥隱沒，逐漸人去樓空的一樓大廳裡，出現了穿著運動服的一小撮人揮著汗水，迎合著如夏夜微風般的律動，沉浸於太極拳特有的柔順姿態，潑墨出陰與陽交疊變化的進境，在陽明的山景裡藏著有如煉丹隱士的人群，勾勒出如山水畫般的壯麗景象.....
南橫驚艷
(國立陽明大學, 2004-08-16)
楊振宇
;
邱智東
過了花蓮，我們換了車廂，享受坐在椅子上的幸福，並品嘗著遠近馳名的池上便當。茶餘飯飽之際，台東車站也悄悄地到來。此時遠眺遠方翠綠的南橫山區，真想大喊~~南橫，我們來了
國立陽明大學傳統醫藥研究所誠徵
(國立陽明大學, 2004-08-16)
陽明電子報編輯小組
專任教師一名一、資格：符合教育部助理教授級以上聘任資格。二、具中醫系學士背景及中醫師執照者為優先考慮對象。三、有研究經驗並有學術論文發表在SCI期刊者為佳。兼任教師數名一、資格：符合教育部助理教授級以上聘任資格。二、具中醫師執照及博士資格者為優先考慮對象。三、有研究經驗並有學術論文發表在SCI期刊者為佳。符合以上資格者，請將 (1)學位證件及經歷證件影本。 (2)推薦函二封。 (3)著作目錄及代表作。 (4)個人簡歷自傳。寄至「112台北市北投區立農街二段155號陽明大學傳統醫藥研究所教師遴聘委員會」收。截止日期：中華民國93年9月14日止(以郵戳為憑)。
邀你去旅行
(國立陽明大學, 2004-08-16)
陽明電子報編輯小組
有的人在國內，親子同往宜蘭冬山河參加童玩節；或是報名學校舉辦的自強活動，到澎湖一遊；或是三五好友興沖沖的跑去南橫，卻差點受困…… 有的人去國外，到香港三天兩夜，住五星級飯店也才一萬多，又可享受美食；再不然到布拉格消費也很便宜，景色又美；想想，北海道現在正盛開著夏季限定的薰衣草…… 真巧，這一期的電子報內容，好多都和旅行有關呢！＜焦點新聞＞中，生化所翟建富老師奉派至菲律賓訪問，藉此推動兩國的學術交流與合作。＜陽明人＞中，課輔組左智慧遠赴外蒙，為我們攜回她在「額爾登特」辦理青年夏令營的歷練。＜天涯行旅＞中，醫工所幾位研究生抽空登上南橫，卻差點受困山區；儀器中心蘇元澤從北海道捎來幸福。＜脈脈含青＞中，左智慧隨著登山社一步一腳印，踏上了奇萊北峰和主峰…… ＜脈脈含青＞和＜藝事型態＞是電子報這一期新闢的專欄，希望能呈現陽明人多變化的生活風貌。出遊回來，記得要投稿唷！
陽明歷史照片巡禮
(國立陽明大學, 2004-08-16)
陽明電子報編輯小組
發黃的照片是否可以讓你陷入時間的隧道中？在這時光隧道中是否勾起你想念的人物、想念的事情？在這初春的時節，電子報於本期起將分次把得來不易的百來張珍貴校園照片逐一向大家介紹，希望隨著這些圖像的重現，再次將大夥的情感凝聚起來！