Browsing by Issue Date, starting with "2005-06-20"

Now showing 1 - 20 of 66461

Study of thermal stability of nickel monogermanide on single- and polycrystalline germanium substrates
(2005-06-20)
Hsu, SL
;
Chien, CH
;
Yang, MJ
;
Huang, RH
;
Leu, CC
We have investigated the thermal stability of nickel monogermanide (NiGe) films formed by rapid thermal annealing on both single- and polycrystalline Ge substrates. We found that the NiGe phase is the only one present after nickel germanidation in the temperature range 400-700 degrees C. A fairly uniform NiGe film formed on the single-crystalline Ge; it possessed excellent resistivity (15.6 mu Omega cm) and was thermally stable up to 550 degrees C, but it degraded rapidly at higher temperatures as a result of agglomeration. In contrast, the NiGe film formed on the polycrystalline Ge exhibited much poorer thermal stability, possibly because of polycrystalline Ge grain growth, which resulted in columnar NiGe grains interlaced with Ge grains that had a dramatically increased sheet resistance. As a result, we observed that the sheet resistances of NiGe lines subjected to annealing at 500 degrees C depended strongly on the linewidth when this width was comparable with the grain size of the polycrystalline Ge. (c) 2005 American Institute of Physic's.
Highly efficient top-emitting white organic electroluminescent devices
(2005-06-20)
Hsu, SF
;
Lee, CC
;
Hwang, SW
;
Chen, CH
;
應用化學系
We have developed highly efficient white top-emitting organic light-emitting devices with broad emission by modifying both the anode and cathode. To alleviate the undesirable microcavity effect and obtain "broad" white emission, a CFx-coated Ag anode and an index-matching layer (SnO2) capped on a thin Ca/Ag cathode with a maximum transparency of 80% were employed. A top-emitting broad white-light device, based on the dual-layer architecture of light blue and yellow emitters with one of the highest EL efficiencies of 22.2 cd/A (9.6 1m/W) at 20 mA/cm(2) and 7.3 V with Commission Internationale d'Eclairage coordinates of (x = 0.31, y = 0.47), has been demonstrated. (c) 2005 American Institute of Physics.
一種光強度與分波多工之光纖布拉格光柵感測系統
(2005-06-21)
祁甡
;
曾弘毅
;
彭朋群
;
林加和
一種光強度與分波多工之光纖布拉格光柵感測系統其包括一具有收發端部及感測端部之分光裝置、耦合於收發端部之光產生裝置及光接收裝置、複數耦合於感測端部且具有光纖布拉格光柵之感測光纖及一連接光接收裝置之資訊處理裝置，該分光裝置係將收發端部之光源以不同能量比例分配至感測端部，因此，由光產生裝置輸出之可調波長光訊號，經分光裝置以不同能量比例配置至感測光纖，而對應光波長之光柵係以不同能量比例反射光訊號，經光接收裝置擷取其能量資訊，並資訊處理裝置依光訊號能量比例決定感測結果，可形成光強度多工機制，提升感測容量。
Experimental and theoretical studies of rate coefficients for the reaction O(P-3)+CH3OH at high temperatures
(2005-06-22)
Lu, CW
;
Chou, SL
;
Lee, YP
;
Xu, SC
;
Xu, ZF
Rate coefficients of the reaction O(P-3)+CH3OH in the temperature range of 835-1777 K were determined using a diaphragmless shock tube. O atoms were generated by photolysis of SO2 with a KrF excimer laser at 248 nm or an ArF excimer laser at 193 nm; their concentrations were monitored via atomic resonance absorption excited by emission from a microwave-discharged mixture of O-2 and He. The rate coefficients determined for the temperature range can be represented by the Arrhenius equation, k(T)=(2.29 +/- 0.18)x10(-10) exp[-(4210 +/- 100)/T] cm(3) molecule(-1) s(-1); unless otherwise noted, all the listed errors represent one standard deviation in fitting. Combination of these and previous data at lower temperature shows a non-Arrhenius behavior described as the three-parameter equation, k(T)=(2.74 +/- 0.07)x10(-18)T(2.25 +/- 0.13) exp[-(1500 +/- 90)/T] cm(3)molecule(-1) s(-1). Theoretical calculations at the Becke-3-Lee-Yang-Parr (B3LYP)/6-311+G(3df,2p) level locate three transition states. Based on the energies computed with coupled clusters singles, doubles (triples) [CCSD(T)]/6-311+G(3df,2p)//B3LYP/6-311+G(3df,2p), the rate coefficients predicted with canonical variational transition state theory with small curvature tunneling corrections agree satisfactorily with the experimental observations. The branching ratios of two accessible reaction channels forming OH+CH2OH (1a) and OH+CH3O (1b) are predicted to vary strongly with temperature. At 300 K, reaction (1a) dominates, whereas reaction (1b) becomes more important than reaction (1a) above 1700 K. (c) 2005 American Institute of Physics.
[DOUBLE-TRIGGERED SILICON CONTROLLING RECTIFIER AND ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT THEREOF]
(2005-06-23)
Ker, Ming-Dou
;
Hsu, Kuo-Chun
A double-triggered silicon controller rectifier (SCR) comprises a plurality of N+ diffusion areas, a plurality of P+ diffusion areas, a first N-well region, a second N-well region and a third N-well region formed in a P-substrate. The N+ diffusion areas and the P+ diffusion areas are isolated by shallow trench isolation (STI) structures. Two of the N+ diffusion areas are N-type trigger terminals. Two of the P+ diffusion areas are the P-type trigger terminal.
Comment on "Formation of repetitively nanosecond spatial solitons in a saturable absorber Q-switched laser" - Reply
(2005-06-24)
Chen, YF
;
Huang, KF
;
電子物理學系
;
Department of Electrophysics
EXTRACTION OF CORONARY ARTERIAL TREE USING CINE X-RAY ANGIOGRAMS
(2005-06-25)
Lin, Chih-Yang
;
Ching, Yu-Tai
;
資訊工程學系
;
Department of Computer Science
An efficient and robust method for identification of coronary arteries and evaluation of the severity of the stenosis on the routine X-ray angiograms is proposed. It is a challenging process to accurately identify coronary artery due to poor signal-to-noise ratio, vessel overlap, and superimposition with various anatomical structures such as ribs, spine, or heart chambers. The proposed method consists of two major stages: (a) signal-based image segmentation and (b) vessel feature extraction. The 3D Fourier and 3D Wavelet transforms are first employed to reduce the background and noisy structures in the images. Afterwards, a set of matched filters was applied to enhance the coronary arteries in the images. At the end, clustering analysis, histogram technique, and size filtering were utilized to obtain a binary image that consists of the final segmented coronary arterial tree. To extract vessel features in terms of vessel centerline and diameter, a gradient vector-flow based snake algorithm is applied to determine the medial axis of a vessel followed by the calculations of vessel boundaries and width associated with the detected medial axis.
吃茶圖卷
(2005-06-28)
管管
Using a solution crystal growth method to grow arrays of aligned, individually distinct, single-crystalline TiO2 nanoneedles within nanocavities
(2005-06-28)
Weng, CC
;
Chen, CP
;
Ting, CH
;
Wei, KH
;
材料科學與工程學系
Preparation and properties of polyacrylate/clay photocured nanocomposite materials
(2005-06-28)
Wang, YY
;
Hsieh, TE
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A functionalized surfactant, GME-N-C-10 containing a C=C double bond, was synthesized to modify clays such as montmorillonite (MMT) and mica for the preparation of organic-inorganic composite resins via radical photoinduced polymerization. As revealed by X-ray diffraction (XRD) analysis of the organophilic samples, the synthesized surfactant was successfully intercalated into the layers of clay by its full molecular length and such an intercalation generated a paraffin-like structure in the modified clays. By forming the C-C bonds between surfactants and oligomers/monomers during subsequent radical photoinduced polymerization, the hybrid comprising organophilic clay/oligomers/monomers became an intercalated nanocomposite resin. The thickness of the dispersed lamellae was less than 100 nm, as revealed by transmission electron microscopy (TEM). For the composite sample containing 5.0 wt.% of organophilic clay, the decomposition temperatures raised at least 15 degrees C; the transmittance detected by UV-visible spectrometer showed a less than 15% loss in the visible light region but a satisfactory transparency was still retained, and the degree of moisture absorption decreased from 3.4% to about 1% due to dispersive organophilic clay in the polymer matrix.
Highly efficient electrophosphorescent devices with saturated red emission from a neutral osmium complex
(2005-06-28)
Niu, YH
;
Tung, YL
;
Chi, Y
;
Shu, CF
;
Kim, JH
Highly efficient electrophosphorescent polymer light-emitting diodes (LEDs) with saturated red emission (Commission Internationale de L'Eclairage chromaticity coordinates exactly at x = 0.67, y = 0.33) are achieved by blending a novel neutral Osmium complex into a single-component bipolar polymer host that possesses balanced hole- and electron-transporting ability. By using a tetraphenylenebiphenyldiamine (TPD)-based cross-linkable hole-transport layer as well as a layer of 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) as an electron-tran sport layer, a device structure with both effective hole/electron injection and efficient carriers/excitons blocking or confinement at both electrode sides is constituted. In this way, external quantum efficiency 12.8% is reached the first time with an organometallic complex with heavy metal core other than iridium.
Band gap variation of size-controlled ZnO quantum dots synthesized by sol-gel method
(2005-06-30)
Lin, KF
;
Cheng, HM
;
Hsu, HC
;
Lin, LJ
;
Hsieh, WF
ZnO quantum dots were synthesized successfully via a simple sol-gel method. The average size of quantum dots can be tailored using well-controlled concentration of zinc precursor. Size-dependent blue shifts of photoluminescence and absorption spectra revealed the quantum confinement effect. The band gap enlargement is in agreement with the theoretical calculation based on the effective mass model. Furthermore, as the particle size decreases, we observed an increase in the size-dependent Stokes shift of the photoluminescence peak relative to the absorption onset. (c) 2005 Elsevier B.V. All rights reserved.
Sol-gel-derived Zn((1-x))Mg(x)O thin films used as active channel layer of thin-film transistors
(2005-07-01)
Lee, JH
;
Lin, P
;
Lee, CC
;
Ho, JC
;
Wang, YW
Sol-gel derived n-type Zn((1-x))Mg(x)O (x = 0-0.45) thin films and thin-film transistors (TFTs) with active channel layers made of the films were investigated. The films were prepared at 500 degrees C. The effects of Mg doping on the crystallinity, optical transparency, grain size, and charge-carrier concentration (n) of the films were examined. The Fermi level of the films, as derived from the temperature dependence of n, was similar to 0.12eV below the conduction band. The donor concentration and donor level (E(d)) were derived by a curve fitting method based on the electrical neutrality condition. Ed was found to be similar to 0.3 eV below the conduction band. The composition dependence of the TFT output characteristics was interpreted and correlated to the width of the depletion region adjacent to the grain boundaries. When the grains were almost depleted at x = 0.2, the TFT showed an enhancement mode and an on/off ratio of 10(6).
A convenient solver for solving optimal control problems
(2005-07-01)
Huang, CH
;
Tseng, CH
;
機械工程學系
;
Department of Mechanical Engineering
This paper focuses on the development of a solver for solving optimal control problems. A developed numerical optimal control module integrated with the Sequential Quadratic Programming method is introduced. An optimal control problem solver based on the proposed method is implemented to solve optimal control problems efficiently in engineering applications. In addition, a systematic procedure for solving optimal control problems by using the optimal control problem solver is also proposed. A time-optimal benchmark problem presented in the literature is used to illustrate for the capability and facility of solving optimal control problems. The numerical results demonstrate the proposed method and the procedure suggested in this paper are helpful to engineers in solving optimal control problems in a systematic and efficient manner.
A robust high-Q micromachined RF inductor for RFIC applications
(2005-07-01)
Lin, JW
;
Chen, CC
;
Cheng, YT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a robust micromachined spiral inductor with a cross-shaped sandwich membrane support is proposed and fabricated with fully CMOS compatible post-processes for radio frequency integrated circuit (RFIC) applications. Via the incorporation of a sandwich dielectric membrane (0.7 mu M SiO2/0.7 mu M Si3N4/0.7 mu m TEOS) to enhance the structure rigidity, the inductor can have better signal stability. In comparison, the new design of a similar to 5-nH micromachined inductor can have 45% less inductance variation than the one without the dielectric support while both devices are operated with 10 m/s(2) acceleration. Meanwhile, using a cross shape instead of blanket membrane can also effectively eliminate the inductance variation induced by the working temperature change (20 degrees C to 75 degrees C). The measurement results show the robust inductor can have similar electrical performance to the as-fabricated freely suspended inductor, which has five times Q (quality factor) improvement than the inductor without the substrate removal. It is our belief that the new micromachined inductors can have not only high-Q performance but also better signal stability suitable for wide-range RFIC applications.
Machine learning with automatic feature selection for multi-class protein fold classification
(2005-07-01)
Huang, CD
;
Liang, SF
;
Lin, CT
;
Wu, RC
;
電控工程研究所
In machine learning, both the properly used networks and the selected features are important factors which should be considered carefully. These two factors will influence the result, whether for better or worse. In bioinformatics, the amount of features may be very large to make machine learning possible. In this study we introduce the idea of feature selection in the problem of bioinformatics. We use neural networks to complete our task where each input node is associated with a gate. At the beginning of the training, all gates are almost closed, and, at this time, no features are allowed to enter the network. During the training phase, gates are either opened or closed, depending oil the requirements. After the selection training phase has completed, gates corresponding to the helpful features are completely opened while gates Corresponding to the useless features are closed more tightly. Some gates may be partially open, depending oil the importance of the corresponding features. So, the network can not only select features in an online manner during learning, but it also does some feature extraction. We combine feature selection with our novel hierarchical machine learning architecture and apply it to multi-class protein fold classification. At the first level the network classifies the data into four major folds: all alpha, all beta, alpha + beta and alpha/beta. In the next level, we have another set of networks which further classifies the data into twenty-seven folds. This approach helps achieve the following. The gating network is found to reduce the number of features drastically. It is interesting to observe that, for the first level using just 50 features selected by the gating network, we can get a test accuracy comparable to that using 125 features in neural classifiers. The process also helps us get a better insight into the folding process. For example, tracking the evolution of different gates, we call find which characteristics (features) of the data are more important for the folding process. Eventually, it reduces the computation time. The use of the hierarchical architecture helps LIS get a better performance also.
Histidine residue at position 234 of oxidosqualene-lanosterol cyclase from Saccharomyces cerevisiae simultaneously influences cyclization, rearrangement, and deprotonation reactions
(2005-07-01)
Wu, TK
;
Liu, YT
;
Chang, CH
;
應用化學系分子科學碩博班
;
Institute of Molecular science
Histidine Residue at Position 234 of Oxidosqualene-Lanosterol Cyclase from Saccharomyces cerevisiae Simultaneously Influences Cyclization, Rearrangement, and Deprotonation Reactions
雙觸發矽控整流元件與使用其之靜電保護電路
(2005-07-01)
柯明道
;
徐國鈞
一種雙觸發矽控整流元件與使用其之靜電保護電路。此種雙觸發矽控整流元件係在一個P型基底中配置了數個N＋擴散區域、數個P＋擴散區域、第一N型井區域、第二N型井區域和第三N型井區域。每一個N＋擴散區域和P＋擴散區域中間，都以淺溝渠結構加以隔離。在P＋擴散區域內的其中二個，係雙觸發矽控整流元件的P型觸發區。而在N＋擴散區域內的其中二個，係雙觸發矽控整流元件的N型觸發區。
Electron-phonon-impurity interference effect in disordered Au56Pd44 and IrO2 thick films
(2005-07-01)
Yeh, SS
;
Lin, JJ
;
Jing, XN
;
Zhang, DL
;
電子物理學系
We have fabricated a series of Au56Pd44 thick films with a wide range of residual resistivity rho(0) varying from 40 to 280 mu Omega cm. The resistivities of these films were measured between 15 and 300 K. We found that at temperatures below about 0.1 theta(D) (theta(D) is the Debye temperature), the interference mechanism between the elastic electron scattering and electron-phonon scattering (the electron-phonon-impurity interference effect) contributes significantly to the measured resistivities. Our results support the current theoretical idea that this interference-mechanism-induced resistivity varies with rho(0)T(2), where T is the temperature. Similar observation has also been made in disordered, conducting transition-metal oxide IrO2 thick films.
Punching shear strength of reinforced concrete slabs strengthened with glass fiber-reinforced, polymer laminates
(2005-07-01)
Chen, CC
;
Li, CY
;
土木工程學系
;
Department of Civil Engineering
This study investigates the punching shear strength and failure behavior of reinforced concrete slabs strengthened with glass fiber-reinforced polymer (GFRP) laminates. The parameters of the 18 specimens.studied herein are concrete compressive strength, steel reinforcement ratio, and the number of GFRP laminate layers. The specimens were tested simply supported along the four sides of the slabs and loaded through the stub column. The behavior of the concrete slabs reinforced with GFRP laminates in addition to steel reinforcement is compared to that of slabs with steel reinforcement. Experimental test results indicate that applying GFRP laminates markedly increases the punching shear capacity of slab-column connections. Based on these results, a design procedure is presented to calculate the ultimate punching shear strength of slab-column connections strengthened by the GFRP laminates. Good correlations between predicted and experimental results have been achieved.