Browsing by Issue Date, starting with "2005-05-15"

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Strong anisotrpoic maganetoresistance and magnetic interaction in La0.7Ce0.3Mn0.3/La0.7Ca0.3MnO3 p-n junction
(2005-05-15)
Chou, H
;
Hong, ZY
;
Sun, SJ
;
Juang, JY
;
Chang, WJ
The p-n junction made by colossal magnetoresistance materials, such as La0.7Ce0.3MnO3/La0.7Ca0.3MnO3, has great interest for its potential applications. However, the physics of the magnetic state and transport properties of the interface still remains open. In this article, bilayer La0.7Ce0.3MnO3/La0.7Ca0.3MnO3/STO films with a nearly perfect interface were studied. The p-n interface possibly becomes an antiferromagnetion-insulating layer as their parent compound, LaMnO3, and confines the bias current flowing only on the top layer. The top and bottom layers interact with each other in a way that a strong anisotropy tin magnetoresistance measurements was observed. (c) 2005 American Institute of Physics.
Magnetic force-induced damping effect for magnetic bearing motor
(2005-05-15)
Wang, CC
;
Yao, YD
;
Chang, YH
;
Tung, PC
;
Xiao, RB
An innovative damping induced by magnetic force was designed successfully for a totally passive magnetic bearing motor. A magnetic ring of high permeability and an annular-shaped rubber pad were mounted on the stator 0.55 mm below the permanent magnet of the rotor. Computer simulations were compared with experimental measurements to decide on the material and configuration of the critical components. The natural frequencies for lateral and rotational modes of the rotor are around 22 Hz measured by impulse method. Both the magnetic bearing motor with and without magnetic damping are rotated at a rated speed of 3840 rpm, which is far above the first critical speed of 1305 rpm. Without magnetic damping, the natural damping ratio in the radial direction of the rotor is 0.0655. After damping, it increases to 0.1401. We have demonstrated by both experimental measurement and theoretical calculation that the antishock performance is significantly improved by the innovative damping technology in a passive magnetic bearing motor. (c) 2005 American Institute of Physics.
Pattern formations and spatial entropy for spatially discrete diffusion equations
(2005-05-15)
Cheng, CY
;
Shih, CW
;
應用數學系
;
Department of Applied Mathematics
Formation of mosaic patterns for spatially discrete diffusion equations with cubic nonlinearity is investigated. We construct feasible basic patterns in each parameter region and combine these basic patterns into large patterns on one- and two-dimensional lattices. The basic patterns are characterized and constructed through formulating parameter conditions based on a geometrical setting. Spatial entropy associated with these patterns are computed or estimated. We also consider three typical boundary conditions and investigate their influences on pattern formations and spatial entropy. Several numerical computations are performed to illustrate such a formation of patterns. (c) 2005 Elsevier B.V. All rights reserved.
Temperature dependence of vortex configuration by honeycomb hole arrays in a superconducting Nb film
(2005-05-15)
Wu, TC
;
Wang, JC
;
Horng, L
;
Wu, JC
;
Yang, TJ
A honeycomb array of submicrometer holes in a Nb superconducting thin film has been fabricated to investigate the flux pinning effect. It is found that the minima positions reveal two regimes characterized by the matching fields and the fractional ones. It is believed that the complex behavior may come from more than one vortex being captured per pinning site. Furthermore, the temperature dependence of the saturation number of vortices per pinning site together with vortex-vortex interaction gives the complex vortex configurations. (c) 2005 American Institute of Physics.
Current-assisted magnetization switching in submicron permalloy S-shape wires with narrow junctions
(2005-05-15)
Chen, YC
;
Lin, YA
;
Chen, DC
;
Yao, YD
;
Lee, SF
We report the results of the current-assisted magnetization switching in submicron permalloy S-shape wires with narrow junctions (or notches). Domain walls were initially formed and pinned in the vicinity of the notches. Two distinct behaviors are observed in the current-assisted magnetization reversal process. When the applied field is near switching field (Delta H < 7 Oe), the injected current directly switched the wire magnetization, and the needed critical current varied linearly and significantly with the field intensity. In contrast, when the field is relatively far from the switching field (Delta H > 7 Oe), the current only moves the domain wall to a local stable state, and the critical current varied slightly with the field. Moreover, two resistance jumps during current scanning are observed in the cases with magnetization reversals. These results reveal that the current driven effect is closely related to the initial domain states, and are explained by a theoretical model based on spin transfer effect. (c) 2005 American Institute of Physics.
Effect of incorporated CdS nanoparticles on the crystallinity and morphology of poly (styrene-b-ethylene oxide) diblock copolymers
(2005-05-15)
Yeh, SW
;
Wu, TL
;
Wei, KH
;
Sun, YS
;
Liang, KS
Surface-modified CdS nanoparticles selectively dispersed in hexagonally packed poly(ethylene oxide) (PEO) cylinders of poly(styrene-b-ethylene oxide) (PSEO) block copolymers were prepared. The photoluminescence and ultraviolet-visible characteristics of the presynthesized CdS nanoparticles in N,N-dimethylformamide and in PEO domains of the PSEO block copolymers were determined. Because of strong interactions between the CdS nanoparticles and PEO chains, as shown by Fourier transform infrared spectroscopy, the incorporation of the CdS nanoparticles prevented the PEO cylinders from properly crystallizing; this was confirmed by differential scanning calorimetry and wide-angle X-ray diffraction measurements. The intercylinder distance between the swollen and reduced-crystallinity CdS/PEO cylinders in turn increased, as confirmed by small-angle X-ray scattering and transmission electron microscopy. At a high CdS concentration (43 wt % or 8.3 vol % with respect to PEO), however, the hexagonally packed cylindrical nanostructure of the PSEO diblock copolymers was destroyed. (c) 2005 Wiley Periodicals, Inc.
Optimal design of fine magnetic pole pitch fabricated on printed circuit board
(2005-05-15)
Chiu, KC
;
Huang, DR
;
Shieh, HPD
;
光電工程學系
;
Department of Photonics
Using traditional methods, a permanent magnet multipole component magnetized with a magnetic pole pitch of less than 1 mm is very difficult to achieve and a costly, complicated magnetization system is required. In this paper, the optimal design of a fine magnetic pole pitch of less than 1 mm fabricated on a printed circuit board has been successfully investigated and demonstrated. An optimal magnetic pole pitch having large variation and strength in magnetic-flux density was obtained. The characteristics of the optimal magnetic pole pitch are good for signal detection and processing. The measured values of the magnetic-flux density in the z component are in agreement with the calculated values. (c) 2005 American Institute of Physics.
Perpendicular interface resistance in Co/NbxTi1-x multilayers for normal and superconducting NbTi alloy with x=0.4, 0.6
(2005-05-15)
Huang, SY
;
Lee, SF
;
Huang, JC
;
Hwang, GH
;
Yao, YD
We report here the resistance of Co/NbxTi1-x multilayers, for x=0.4 and 0.6, with current flowing perpendicular to the layer plane at 4.2 K. When NbTi films are sandwiched between Co, we found that there are critical thicknesses of 20 nm for x=0.4 and 27 nm for x=0.6, below which no superconducting transition could be found. Using a series resistor model, we extracted the unit area resistance of one pair of Co/NbTi interfaces and compared with the pure Nb case we have reported. The influence of mean free paths and superconducting coherence lengths is analyzed. (c) 2005 American Institute of Physics.
Fiber Bragg grating sequential UV-writing method with real-time interferometric side-diffraction position monitoring
(2005-05-16)
Hsu, KC
;
Sheu, LG
;
Chuang, KP
;
Chang, SH
;
Lai, YC
This work presents a new sequential UV-writing procedure for fabricating long fiber Bragg grating (FBG) devices. To real-time accurately align the position of every exposed FBG section prior to UV exposure, a single-period reference fiber grating with strong refractive index modulation is probed by applying an interferometric side-diffraction method to measure the grating phase as the position reference. In this way the overlapped FBG sections can be connected section-by-section without obvious phase errors, even when the written index-modulation is weak. (C) 2005 Optical Society of America.
Highly efficient blue organic light-emitting devices incorporating a composite hole transport layer
(2005-05-16)
Liao, CH
;
Lee, MT
;
Tsai, CH
;
Chen, CH
;
應用化學系
Organic light-emitting devices (OLEDs) incorporating the copper phthalocyanine (CuPc)/N,N-'-bis-(1-naphthyl)-N,N-'-diphenyl-1,1(')-biphenyl-4,4(')-diamine composite hole transport layer have been fabricated. Under optimal condition, the highly efficient sky-blue OLED based on the aminosubstituted distyrylarylene fluorescent dye, doped in the stable diphenyanthracene blue host achieved a luminance efficiency of 16.2 cd/A with a Commission Internationale d' Eclairage (CIE)(x,y) color coordinate of [0.15, 0.29] at 6.4 V (20 mA/cm(2)) and an external quantum efficiency of 8.7%. (c) 2005 American Institute of Physics.
高解析度智慧型階次診斷系統及其診斷方法
(2005-05-16)
白明憲
;
洪銘宏
;
黃嘉閔
;
蘇富誠
本發明係關於一種高解析度智慧型階次診斷系統及其診斷方法，其係用於旋轉設備之頻率階次分析(order analysis)與診斷，包括：資料擷取裝置，機台資料建立裝置，時頻譜分析和再取樣分析裝置，卡氏濾波器(Kalman filter)或遞迴最小平方演算法(RLS)分析裝置，模糊判斷裝置，視窗介面(GUI)裝置，其中該系統係反覆施行前述各裝置之功能，以隨時獲取該旋轉設備之診斷結果。
Recombination distribution and color tuning of multilayer organic light-emitting diode
(2005-05-16)
Chen, CH
;
Meng, HF
;
物理研究所
;
Institute of Physics
The recombination distribution of an organic light-emitting diode with multiple emissive layers is studied theoretically. Due to the relatively low electron mobility, the recombination concentrates in the layer next to the cathode. As the voltage increases, the recombination extends to the subsequent layers because the electric field strongly enhances the electron mobility. Assume that the layers are arranged in the order of red, green, blue, and electron blocking from the cathode, the emission color can be continuously tuned by the voltage over a wide range. Taking typical material parameters and emission spectra for the layers, we show that Commission Internationale de L'Eclairage coordinate can move from (0.5,0.5) (orange) to (0.3,0.5) (green) to (0.2,0.3) (blue) as the voltage increases from 3 to 13 V. The ratio between the electron and hole mobilities of the green layer and the electron barrier between green and blue layers is found to be crucial for the wide range of color tunability. (c) 2005 American Institute of Physics.
Highly efficient blue organic light-emitting devices incorporating a composite hole transport layer
(2005-05-16)
Liao, CH
;
Lee, MT
;
Tsai, CH
;
Chen, CH
;
應用化學系
Organic light-emitting devices (OLEDs) incorporating the copper phthalocyanine (CuPc)/N,N-'-bis-(1-naphthyl)-N,N-'-diphenyl-1,1(')-biphenyl-4,4(')-diamine composite hole transport layer have been fabricated. Under optimal condition, the highly efficient sky-blue OLED based on the aminosubstituted distyrylarylene fluorescent dye, doped in the stable diphenyanthracene blue host achieved a luminance efficiency of 16.2 cd/A with a Commission Internationale d' Eclairage (CIE)(x,y) color coordinate of [0.15, 0.29] at 6.4 V (20 mA/cm(2)) and an external quantum efficiency of 8.7%. (c) 2005 American Institute of Physics.
含氟廢水之處理方式
(2005-05-16)
江萬豪
;
黃志彬
;
林昌隆
本發明是在提供一種含氟廢水之處理方式，係在進流之含氟廢水中提供碳酸根離子，如此可在提供鈣離子時，於反應槽中形成「氟化鈣-碳酸鈣」之共沉降，後續可視需求加入鋁鹽混凝，可進一步令廢水顆粒自數微米放大至數百甚至上千微米。
Threshold current density of electromigration in eutectic SnPb solder
(2005-05-16)
Yeh, YT
;
Chou, CK
;
Hsu, YC
;
Chen, C
;
Tu, KN
Electromigration has emerged as an important reliability issue in the microelectronics packaging industry since the dimension of solder joints has continued to shrink. In this letter, we report a technique that enables the precise measurement of the important parameters of solder electromigration, such as activation energy, critical length, threshold current density, effective charge numbers, and electromigration rate. Patterned Cu/Ti films in a Si trench were employed for eutectic SnPb solder to be reflowed on, and thus solder Blech specimens were fabricated. Atomic force microscope was used to measure the depletion volume caused by electromigration on the cathode end. The threshold current density is estimated to be 8.5x10(3) A/cm(2) at 100 degrees C, which relates directly to the maximum allowable current that a solder joint can carry without electromigration damage. This technique facilitates the scientifically systematic investigation of electromigration in solders. (c) American Institute of Physics.
An almost-linear time and linear space algorithm for the longest common subsequence problem
(2005-05-16)
Guo, JY
;
Hwang, FK
;
應用數學系
;
Department of Applied Mathematics
There are two general approaches to the longest common subsequence problem. The dynamic programming approach takes quadratic time but linear space, while the nondynamic-programming approach takes less time but more space. We propose a new implementation of the latter approach which seems to get the best for both time and space for the DNA application. (c) 2005 Elsevier B.V. All rights reserved.
生化感測方法及其感測裝置
(2005-05-16)
楊裕雄
;
吳重雨
;
盧武德
;
施育全
;
胡智朋
本發明係一種生化感測方法及其感測裝置，利用此生化感測方法之感測裝置係包括一感光二極體，其可感測特定化合物與特定酵素及顯光劑反應後所產生之光，並能將所感測之光訊號轉換為電流訊號；另有一電流／電壓轉換電路可將該電流訊號轉換為類比電壓訊號；且此類比電壓訊號經由一類比／數位轉換器可再轉換為數位電壓訊號；最後利用一電子裝置可接收此數位電壓訊號並對其加以分析，藉此分析動作以測定該特定化合物之含量多寡。本發明之方法及裝置可提供簡易、大量而即時之醫療檢測，可改善習知檢測技術而使用之光譜分析儀體積過大且價格過高之缺失。
An intelligent GGSN dispatching mechanism for UMTS
(2005-05-16)
Cheng, SM
;
Lin, P
;
Tu, GH
;
Fu, LC
;
Liang, CF
3GPP proposed the Universal Mobile Telecommunication System (UMTS) to provide high-speed wireless transmission services to mobile users. To efficiently route the packets, the PDP contexts are maintained in the UE, SGSN, and GGSN in the UMTS network. Before beginning a session, the PDP Context Activation procedure is exercised to create the PDP contexts, where the SGSN selects one GGSN to serve the UE based on an IP list (for all GGSNs that can serve the UE). If the selected GGSN does not accept the request due to exception events, the SGSN chooses another GGSN until the list is exhausted, which may cause unbalance-loaded GGSNs, redundant traffic load to the network, introduce delay for the PDP context activation procedure, and thus decrease QoS for the UNITS network. To resolve the above issues, this paper proposes an intelligent GGSN dispatch mechanism 'IGD' with different sorting algorithms. The proposed mechanism is considered practical and easily installed in the existing UMTS network. We also conduct simulation experiments to investigate the performance of the IGD mechanism. (c) 2004 Elsevier B.V. All rights reserved.
UV-LIGA interferometer biosensor based on the SU-8 optical waveguide
(2005-05-17)
Shew, BY
;
Kuo, CH
;
Huang, YC
;
Tsai, YH
;
機械工程學系
SU-8 resist was used as a core/cladding waveguide material to fabricate a Mach-Zehnder interferometer (MZI) for biochemical sensing. The refractive index of the SU-8 resist was fine-tuned with a Delta n of 0.004 for single-mode transmission. The UV lithography processes of the SU-8 resist were also optimized to pattern the high resolution (1 mu m) and high aspect ratio (A(R) = 6) Y-branch structure of the optical interferometer. Optical measurements reveal that the SU-8 MZI chip can efficiently transmit the NIR laser (lambda = 13 10 mu) with a total loss less than 6 dB. When one branch of the MZI is in contact with the analyte, the interfered intensity stabilizes after the soaking time exceeds 5 min. NaCl solution with a concentration of 10(-9) g/l can be detected using the SU-8 MZI chip. In the future, the polymer MZI chip can be mass-produced by molding process (or the LIGA process). The low-cost, label-free, real-time and high-sensitivity MZI chip will benefit many applications related to biological, environmental and industrial detection. (c) 2005 Elsevier B.V. All rights reserved.
聆聽趙寧老師的「亞馬遜生活二十年」
(國立陽明大學, 2005-05-17)
陽明電子報編輯小組
第一眼看到生科系發出趙寧老師演講「亞馬遜生活二十年」的訊息時，我立刻去電聯絡人楊助教：「這個趙寧老師是不是那個趙寧老師？」在獲得否定的答案後，我還是很好奇的想要聽聽看演講的內容