Browsing by Issue Date, starting with "2009-09-09"

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Journey from Mo-Mo Quadruple Bonds to Quintuple Bonds
(2009-09-09)
Tsai, Yi-Chou
;
Chen, Hong-Zhang
;
Chang, Chie-Chieh
;
Yu, Jen-Shiang K.
;
Lee, Gene-Hsiang
Heating K(4)Mo(2)Cl(8) and 2 equiv of Li[RC(NDipp)(2)] (R = H, Ph; Dipp = 2,6-i-Pr(2)C(6)H(3)) in tetrahydrofuran (THF) at 60 degrees C gives two paddlewheel type quadruply bonded dimolybdenum complexes, Mo(2)(mu-Cl)[Cl(2)Li(OEt(2))][mu-eta(2)-RC(N-2,6-i-Pr(2)C(6)H(3))(2)](2) (R = H (1), Ph (2)). The Mo-Mo bond lengths of 1 and 2 are 2.0875(4) and 2.0756(8) angstrom, respectively, indicating typical Mo-Mo quadruple bonds. Reduction of 1 and 2 by two electrons results in the isolation of their corresponding Mo-Mo quintuple bonded complexes, Mo(2)[mu-eta(2)-RC(N-2,6-i-Pr(2)C(6)H(3))(2)](2) (R = H (3), Ph (4)), and the Mo-Mo bond lengths dramatically decrease to 2.0187(9) angstrom (3) and 2.0157(4) angstrom (4), a consequence of the formation of the second delta bond and representing the shortest metal-metal bonds beyond the first row elements. The Mo-Mo quintuple bonding characters are corroborated by DFT calculations at the level of BP86/def2-TZVP and BP86/def2-TZVPP.
A Bipolar Host Material Containing Triphenylamine and Diphenylphosphoryl-Substituted Fluorene Units for Highly Efficient Blue Electrophosphorescence
(2009-09-09)
Hsu, Fang-Ming
;
Chien, Chen-Han
;
Shu, Ching-Fong
;
Lai, Chin-Hung
;
Hsieh, Cheng-Chih
Highly efficient blue electrophosphorescent organic light-emitting diodes incorporating a bipolar host, 2,7-bis(diphenylphosphoryl)-9-[4-(N,N-diphenylamino)phenyl]-9-phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C(2)]picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron-donating (p-type) triphenylamine group and an electron-accepting (n-type) 2,7-bis(diphenylphosphoryl)fluorene segment linked through the sp(3)-hybridized C9 position of the fluorene unit. The lack of conjugation between these p- and n-type groups endows POAPF with a triplet energy gap (ET) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue-emitting guest. In addition, the built-in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF-based device doped with 7 wt% FIrpic exhibits a very low turn-on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W(-1)). Even at the practical brightnesses of 100 and 1000cd m(-2), the efficiencies remain high (20.2%/33.8 lm W(-1) and 18.8%/24.3 lm W(-1), respectively), making POAPF a promising material for use in low-power-consumption devices for next-generation flat-panel displays and light sources.
含壓電管致動器之讀寫頭
(2009-09-11)
呂宗熙
;
湯逸君
一種具壓電管致動器之讀寫頭,係包含有一懸臂單元;一與懸臂單元一端連接且為管狀壓電材料之壓電管,該壓電管係分成至少四等分之外部電極,亦即至少兩對電極;以及一與壓電管另一端連接之讀寫頭單元。藉此,可施加電壓於其中一對電極使其包覆的部分壓電材料伸長,而同一對的另一電極施加反向電壓使其縮短,使壓電管產生一維方向的撓曲位移,同理施加電壓於別對電極,也能產生別的方向的撓曲位移,如此利用壓電管進行小行程之多方向位移,以使壓電管達到同時快速、高準確性執行對焦與尋軌的動作,而作為讀寫頭單元之雙軸致動器。
Effects of Ti top electrode thickness on the resistive switching behaviors of rf-sputtered ZrO2 memory films
(2009-09-14)
Wang, Sheng-Yu
;
Lee, Dai-Ying
;
Tseng, Tseung-Yuen
;
Lin, Chih-Yang
;
電子工程學系及電子研究所
In this study, we propose a simple method to produce the various interface thicknesses within Ti/ZrO2 by changing the thickness of the Ti top electrode. As the Ti thickness increases, the induced interface thickness also increases to degrade the dielectric strength of the ZrO2, further lowering the forming voltage. However, when the interface layer is thick enough, it will trap sufficient charges to build up an opposite electric field to increase the forming voltage. The induced interface thickness is found to obviously affect the bias polarity of the resistive switching behavior and the device reliability. A fluctuant ON process is also demonstrated to be attributed to the competition between the formation and rupture of the conducting filaments. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3231872]
Effects of Ti top electrode thickness on the resistive switching behaviors of rf-sputtered ZrO(2) memory films
(2009-09-14)
Wang, Sheng-Yu
;
Lee, Dai-Ying
;
Tseng, Tseung-Yuen
;
Lin, Chih-Yang
;
電子工程學系及電子研究所
In this study, we propose a simple method to produce the various interface thicknesses within Ti/ZrO(2) by changing the thickness of the Ti top electrode. As the Ti thickness increases, the induced interface thickness also increases to degrade the dielectric strength of the ZrO(2), further lowering the forming voltage. However, when the interface layer is thick enough, it will trap sufficient charges to build up an opposite electric field to increase the forming voltage. The induced interface thickness is found to obviously affect the bias polarity of the resistive switching behavior and the device reliability. A fluctuant ON process is also demonstrated to be attributed to the competition between the formation and rupture of the conducting filaments. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3231872]
Detecting HER2 on Cancer Cells by TiO2 Spheres Mile Scattering
(2009-09-15)
Tsai, Min-Chiao
;
Tsai, Tsung-Lin
;
Shieh, Dar-Bin
;
Chiu, Hsin-Tien
;
Lee, Chi-Young
This work is the first to describe a bioimaging method that uses highly uniformly sized TiO2 submicrometer and micrometer spheres based on Mie scattering. Transmembrane proteins (HER2) located on the surface of cancer cells were detected by bonded antibody-linked TiO2 spheres using optic microscopy and UV-vis spectroscopy. A particular HER2 bond on cancer cells, which has a weaker binding affinity than the biotin/avidin interaction, can be identified between TiO2 spheres that are linked to anti-HER2 antibodies and those that are linked to nonspecific mouse IgG antibodies by observing the cells under an optical microscope or by measuring absorbance from a UV-vis spectrum. The TiO2 spheres used in this work was prepared by reacting TTIP with carboxylic acid, as described elsewhere and the uniformity of the TiO2 sphere was further improved by adjusting the amount of water used. The water content was inversely related to particle size and the size distribution: as more water was used, smaller spheres with a narrower size distribution were obtained. The most uniform sphere obtained had a diameter of about 1 mu m with a size variation of 3%.
Method for promoting light emission efficiency of LED using nanorods structure
(2009-09-15)
Huang
;
Hung-Wen
;
Lu
;
Tien-Chang
;
Chiu
Method for the light emitting diode (LED) having the nanorods-like structure is provided. The LED employs the nanorods are subsequently formed in a longitudinal direction by the etching method and the PEC method. In addition, the plurality of the nanorods is arranged in an array so that provide the LED having much greater brightness and higher light emission efficiency than the conventional LED.
A refined cellular automaton model to rectify impractical vehicular movement behavior
(2009-09-15)
Lan, Lawrence W.
;
Chiou, Yu-Chiun
;
Lin, Zih-Shin
;
Hsu, Chih-Cheng
;
運輸與物流管理系註：原交通所+運管所
When implementing cellular automata (CA) into a traffic simulation, one common defect yet to be rectified is the abrupt deceleration when vehicles encounter stationary obstacles or traffic jams. To be more in line with real world vehicular movement, this paper proposes a piecewise-linear movement to replace the conventional particle-hopping movement adopted in most previous CA models. Upon this adjustment and coupled with refined cell system, a new CA model is developed using the rationale of Forbes' et al. car-following concept. The proposed CA model is validated on a two-lane freeway mainline context. It shows that this model can fix the unrealistic deceleration behaviors, and thus call reflect genuine driver behavior in the real world. The model is also capable of revealing Kerner's three-phase traffic patterns and phase transitions among them. Furthermore, the proposed CA model is applied to simulate a highway work zone wherein traffic efficiency (maximum flow rates) and safety (speed deviations) impacted by various control schemes are tested. (C) 2009 Elsevier B.V. All rights reserved.
Optimal control algorithm and neural network for dynamic groundwater management
(2009-09-15)
Chu, Hone-Jay
;
Chang, Liang-Cheng
;
土木工程學系
;
Department of Civil Engineering
Researchers have found that obtaining optimal solutions for groundwater resource-planning problems, while simultaneously considering time-varying pumping rates, is a challenging task. This study integrates any artificial neural network (ANN) and constrained differential dynamic programming (CDDP) as simulation-optimization model, called ANN-CDDP. Optimal solutions for a groundwater resource-planning problem are determined while simultaneously considering time-varying pumping rates. A trained ANN is used as the transition function to predict ground water table under variable pumping conditions. The results show that the ANN-CDDP reduces computational time by as much as 94.5% when compared to the time required by the conventional model. The proposed optimization model saves a considerable amount of computational time for solving large-scale problems. Copyright (c) 2009 John Wiley & Sons, Ltd.
Utilization of four WDM channels with signal rernodulation of OFDM-QAM for 10 Gb/s uplink passive optical networks
(2009-09-15)
Yeh, Chien Hung
;
Chow, Chi Wai
;
光電工程學系
;
Department of Photonics
In this investigation, we experimentally investigate an extended reach (ER) time-division-multiplexed passive optical network (TDM-PON) using four wavelength-multiplexed channels to achieve 16Gb/s downlink and 10 Gb/s uplink traffic. Each downlink signal uses the highly spectral efficient 4 Gb/s OFDM-QAM, and each uplink signal is generated by signal remodulating the downlink signal via a reflective semiconductor amplifier (RSOA) at 2.5 Gb/s non-return-to-zero (NRZ). In addition, the performance of the proposed ER TDM-PON has also been analyzed and discussed. (c) 2009 Elsevier B.V. All rights reserved.
Application of TiO(2) photocatalytic oxidation and non-woven membrane filtration hybrid system for degradation of 4-chlorophenol
(2009-09-15)
Horng, Ren-Yang
;
Huang, Chihpin
;
Chang, Min-Chao
;
Shao, Hsin
;
Shiau, Be-Lain
A system coupling photocatalytic oxidation of titanium dioxide particles separated by non-woven membrane for the degradation of 4-chlorophenol in an aqueous solution was studied. Non-woven membranes with three different pore sizes were applied to compare their specific flux and permeate turbidity. The results showed that when the pore size was slightly smaller than secondary particles of photocatalyst, higher specific flux and lower turbidity permeate were obtained. Four different applied fluxes, 0.25, 0.5, 1.0 and 2.0 m(3)/m(2)/d, were used with a 2.0 mu m pore size non-woven membrane in a continuous system. The results revealed that the transmembrane pressure (TMP) was less than 10 kPa in all applied fluxes, due to the formation of a porous dynamic cake layer on the surface of the membrane. Based on the filtration characteristics of non-woven membranes, we found that cake formation, rather than pore blocking or pore narrowing, was the dominant factor. This phenomenon also resulted in permeate turbidity ranging from 0.5 to 1.5 NTU and non-detectable concentration of TiO(2) in the permeate. At the same time the experimental results indicated that the concentrations of TOC and 4-chlorophenol decreased with decreasing applied flux, and that the concentration of chloride ions increased with decreasing applied flux in a 4-chlorophenol photodegradation test. It showed that 4-chlorophenol could be effectively degraded by this hybrid system with lower TMP and stable applied flux.
Compact optical curvature sensor with a flexible microdisk laser on a polymer substrate
(2009-09-15)
Shih, M. H.
;
Hsu, K. S.
;
Kunag, Wan
;
Yang, Y. C.
;
Wang, Y. C.
We demonstrate a chip-scale compact optical curvature sensor. It consists of a low threshold InGaAsP microdisk laser on a flexible polydimethylsiloxane polymer substrate. The curvature dependence of lasing wavelength was characterized by bending the cavity at different bending radii. The measurements showed that the lasing wavelength decreases monotonously with an increasing bending curvature. A good agreement between experiment and three-dimensional finite-difference time-domain simulation was also obtained. The sensitivity of the compact device to the bending curvature is -23.7 nm/mm from the experiment. (C) 2009 Optical Society of America
Detecting HER2 on Cancer Cells by TiO(2) Spheres Mile Scattering
(2009-09-15)
Tsai, Min-Chiao
;
Tsai, Tsung-Lin
;
Shieh, Dar-Bin
;
Chiu, Hsin-Tien
;
Lee, Chi-Young
This work is the first to describe a bioimaging method that uses highly uniformly sized TiO(2) submicrometer and micrometer spheres based on Mie scattering. Transmembrane proteins (HER2) located on the surface of cancer cells were detected by bonded antibody-linked TiO(2) spheres using optic microscopy and UV-vis spectroscopy. A particular HER2 bond on cancer cells, which has a weaker binding affinity than the biotin/avidin interaction, can be identified between TiO(2) spheres that are linked to anti-HER2 antibodies and those that are linked to nonspecific mouse IgG antibodies by observing the cells under an optical microscope or by measuring absorbance from a UV-vis spectrum. The TiO(2) spheres used in this work was prepared by reacting TTIP with carboxylic acid, as described elsewhere and the uniformity of the TiO(2) sphere was further improved by adjusting the amount of water used. The water content was inversely related to particle size and the size distribution: as more water was used, smaller spheres with a narrower size distribution were obtained. The most uniform sphere obtained had a diameter of about 1 mu m with a size variation of 3%.
Discriminant analysis of the geomorphic characteristics and stability of landslide dams
(2009-09-15)
Dong, Jia-Jyun
;
Tung, Yu-Hsiang
;
Chen, Chien-Chih
;
Liao, Jyh-Jong
;
Pan, Yii-Wen
Landslides can cause the formation of dams, but these dams often fail soon after lake formation. Thus, rapidly evaluating the stability of a landslide dam is crucial for effective hazard mitigation. This study utilizes discriminant analysis based on a Japanese dataset consisting of 43 well documented landslide dams to determine the significant variables, including log-transformed peak flow (or catchment area), and log-transformed dam height, width and length in hierarchical order, which affect the stability of a landslide dam. The high overall prediction power (88.4% of the 43 training cases are correctly classified) and the high cross-validation accuracy (86%) demonstrate the robustness of the proposed discriminant models PHWL (with variables including log-transformed peak flow, and log-transformed dam height, width and length) and AHWL (with variables including log-transformed catchment area, and log-transformed dam height, width and length). Compared to a previously proposed "DBI" index-based graphic approach, the discriminant model AHV - which uses the log-transformed catchment area, dam height, and dam volume as relevant variables - shows better ability to evaluate the stability of landslide dams. Although these discriminant models are established using a Japanese dataset only, the present multivariate statistical approach can be applied for an expanded dataset without any difficulty when more completely documented worldwide landslide-dam data are available. (C) 2009 Elsevier B.V. All rights reserved.
InGaAs-Capped InAs-GaAs Quantum-Dot Infrared Photodetectors Operating in the Long-Wavelength Infrared Range
(2009-09-15)
Lin, Wei-Hsun
;
Tseng, Chi-Che
;
Chao, Kuang-Ping
;
Mai, Shu-Cheng
;
Lin, Shih-Yen
A ten-period InAs-GaAs quantum-dot infrared photodetector (QDIP) with 8-nm In(0.15)Ga(0.85) As capping layer grown after quantum-dot (QD) deposition is investigated. With reduced InAs QD coverage down to 2.0 mono-layers, responses at 10.4 and 8.4 mu m are observed for the device under positive and negative biases, respectively. The phenomenon is attributed to the large Stark effect resulted from the asymmetric band diagrams of the device under different voltage polarities. The demonstration of long-wavelength infrared detections with the simple structures of the InGaAs-capped QDIP is advantageous for the development of multicolor QDIP focal-plane arrays.
High-Performance InGaN-Based Green Resonant-Cavity Light-Emitting Diodes for Plastic Optical Fiber Applications
(2009-09-15)
Huang, Shih-Yung
;
Horng, Ray-Hua
;
Shi, Jin-Wei
;
Kuo, Hao-Chung
;
Wuu, Dong-Sing
High-performance InGaN-based green resonant-cavity light-emitting diodes (RCLEDs) with a plating Cu substrate for plastic optical fiber communication applications are reported. Good stability of emission wavelength was obtained at 0.016 nm/mA. The RCLEDs presents low temperature dependence, showing only a 3% drop in light output power as the temperature increasing from 25 to 85 degrees C. The superior performance can be attributed to the decreased dynamic series resistance and the enhanced thermal dissipation of the heat sink substrate.
Self-Assembly of H-Bonded Side-Chain and Cross-Linking Copolymers Containing Diblock-Copolymeric Donors and Single/Double H-Bonded Light-Emitting Acceptors
(2009-09-15)
Lin, Hong-Cheu
;
Jiang, Meng-Dan
;
Wu, Shen-Chang
;
Jou, Leng-Long
;
Chou, Kai-Pin
A series of diblock-copolymers were synthesized through anionic polymerization of styrene and tert-butyl methacrylate (tBuA) with different monomer ratios, and analogous block-copolymeric derivatives (PS-b-PAA)s with monofunctional carboxylic acid groups were obtained by further hydrolyzation as hydrogen-bonded (H-bonded) proton donors. Via H-bonded interaction, these diblock-coplymeric donors (PS-b-PAA)s were incorporated with luminescent mono-pyridyl/bis-pyridyl acceptors to form single/double H-bonded supramolecules, that is, H-bonded side-chain/cross-linking copolymers, respectively. The supramolecular architectures formed by donor polymers and light-emitting acceptors were influenced by the ratio of acid blocks in the diblock copolymeric donors and the type of single/double H-bonded light-emitting acceptors. Their thermal and luminescent properties can be adjusted by H-bonds, and more than 100 nm of red-shifted photoluminescence (PL) emissions were observed, which depend on the degrees of the H-bonding interactions. Self-assembled phenomena of amphiphilic dibolck copolymers and their H-bonded complexes were confirmed by TEM micrographs, and supramolecular microphase separation of spherical micelle-like morphology was demonstrated to affect the photophysical properties. Polymer light-emitting diode (PLED) devices containing H-bonded complexes showed electroluminescence (EL) emissions of 503-560 nm under turn-on voltages of 7.5-9.0 V, maximum power efficiencies of 0.23-0.37 cd/A (at 100 mA/cm(2)), and maximum luminances of 318-519 cd/m(2) (around 25 V). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4685-4702, 2009
An efficient algorithm for mining high utility itemsets with negative item values in large databases
(2009-09-15)
Chu, Chun-Jung
;
Tseng, Vincent S.
;
Liang, Tyne
;
資訊工程學系
;
Department of Computer Science
Utility itemsets typically consist of items with different values such as utilities, and the aim of utility mining is to identify the itemsets with highest utilities. In the past studies on utility mining, the values of utility itemsets were considered as positive. In some applications, however, an itemset may be associated with negative item values. Hence, discovery of high utility itemsets with negative item values is important for mining interesting patterns like association rules. In this paper, we propose a novel method, namely HUINIV (High Utility Itemsets with Negative Item Values)-Mine, for efficiently and effectively mining high utility itemsets from large databases with consideration of negative item values. To the best of our knowledge, this is the first work that considers the concept of negative item values in utility mining. The novel contribution of HUINIV-Mine is that it can effectively identify high utility itemsets by generating fewer high transaction-weighted utilization itemsets such that the execution time can be reduced substantially in mining the high utility itemsets. In this way, the process of discovering all high utility itemsets with consideration of negative item values can be accomplished effectively with less requirements on memory space and CPU I/O. This meets the critical requirements of temporal and spatial efficiency for mining high utility itemsets with negative item values. Through experimental evaluation, it is shown that HUINIV-Mine outperforms other methods substantially by generating much less candidate itemsets under different experimental conditions. (C) 2009 Elsevier Inc. All rights reserved.
調整光訊號傳輸時間之光放大器
(2009-09-16)
陳智弘
;
高偉哲
;
彭朋群
;
林俊廷
;
施伯宗
本發明揭露一種可調整光訊號傳輸時間之光放大器,其係採用彎曲光波導放大器的方式提高光訊號時間調整能力,只需調整光放大器的增益就可以達到時間調整的效果。
微型光學讀取頭光路裝置
(2009-09-16)
洪國永
;
曾繁根
;
施錫富
本發明為一種微型光學讀取頭(Optical Pickup Head)光路裝置模組,其特點為利用積體化之製程使多個反射微稜鏡將光束進行多次反射與偏折,以縮小光學頭之實體尺寸及省略人工組裝時間,進而達到微型積體化之目標。