Browsing by Issue Date, starting with "2008-01-15"

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Improvement of luminescence from Si nanocrystals with thermal annealing in CO2
(2008-01-15)
Yang, M. D.
;
Chu, A. H. M.
;
Shen, J. L.
;
Huang, Y. H.
;
Yang, T. N.
Photoluminescence (PL) of Si nanocrystals with annealing in CO2 was studied using the continuous and time-resolved PL measurements. The PL intensity enhances as annealing temperature increases, which is attributed to passivation of the nonradiative recombination centers. As the annealing temperature is 950 degrees C the PL intensity has a maximum value, which increases about a factor of 3 than that of the untreated sample. Based on the emission energy dependence of the PL decay time, the depth of carrier localization is found to increase after the annealing in CO2. We suggest that the oxygen atoms desorbed from CO2 diffuse to react with Si nanocrystals and introduce localized states at the Si/SiO2 interface. (C) 2007 Elsevier B.V. All rights reserved.
管管作品兩首
(2008-01-15)
管管
Indoor sound field feature matching for robot's location and orientation detection
(2008-01-15)
Hu, Jwu-Sheng
;
Liu, Wei-Han
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Cheng, Chieh-Cheng
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this work, an indoor sound field feature matching method is proposed and is applied to detect a mobile robot's location and orientation. The sound field feature, captured from a sound source to a pair of microphones, contains the dynamic of the propagation path. Because of the complexity of indoor environment, the features from different path can be distinguished using appropriate models. Gaussian mixture models are utilized in this paper to characterize the phase difference and magnitude ratio distributions between the microphone pair in consecutive data frames. The application provides an alternative thinking compared with traditional methods such as direction of arrival (DOA) using propagation delay. They usually suffer from reverberation, non-line-of-sight and microphone mismatch problems. The experimental results show the method not only has a high recognition rate for robot's location and orientation, but also is robust against environmental noise. (c) 2007 Elsevier B.V. All rights reserved.
Active 433 MHz-W UHF RF-powered chip integrated with a nanocomposite m-MWCNT/polypyrrole sensor for wireless monitoring of volatile anesthetic agent sevoflurane
(2008-01-15)
Chavali, Murthy
;
Lin, Tzu-Hsuan
;
Wu, Ren-Jang
;
Luk, Hsiang-Ning
;
Hung, Shih-Lin
Tiny remote sensors capable of monitoring gases and vapors are having greatest demand due to their potential applications in diverse research fields. In the present work, design and fabrication of an active wireless UHF (433 MHz) RF-powered sensing system for monitoring volatile organic compounds is presented. The developed sensor chip consists of a thin film of gas-responsive composite material, based on modified multiwalled carbon nanotubes (m-MWCNTs) and polypyrrole (Ppy), coated over two comb-like interdigitated gold electrodes. Wireless modules have been integrated with the chemical sensor chip (composite m-MWCNTs/Ppy) and RF components to detect volatile anesthetic agent, fluoromethyl 2,2,2,-trifluoro-1-(trifluoromethyl) ethyl ether (sevoflurane) is demonstrated. (c) 2007 Elsevier B.V. All rights reserved.
管管作品兩首
(2008-01-15)
管管
Novel reactive compatibilization strategy on immiscible polypropylene and polystyrene blend
(2008-01-15)
Hung, Chen-Jui
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Chuang, Hung-Yang
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Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
Polypropylene (PP) and polystyrene (PS) are immiscible and incompatible. Since both PP and PS components possess no reactive functional group, reactive compatibilization of a PP/PS blend is impossible unless certain reactive functional groups are imparted to either PP or PS. In this study we provide a simple approach to reactively compatibilize the nonreactive PP/PS blend system by physically functionalizing PP and PS with the addition of maleic anhydride grafted PP (PP-g-MA) and styrene maleic anhydride random copolymer (SMA), respectively. An epoxy monomer, serving as a coupler and possessing four epoxy groups able to react with the maleic anhydride of PP-g-MA and SMA, was then added during melt blending. Observations of the finer PS domain sizes and improved mechanical properties support the plausibility of reactive compatibilization of this nonreactive PP/PS blend by combining physically functionalized PP and PS with tetra-glycidyl ether of diphenyl dian-Lino methane (TGDDM) in a one-step extrusion process. (C) 2007 Wiley Periodicals, Inc.
管管作品兩首
(2008-01-15)
管管
管管作品兩首
(2008-01-15)
管管
Nonlinear current-voltage characteristics of oxygen-deficient La(0.67)Ca(0.33)MnO(3-y) films
(2008-01-15)
Liu, S. J.
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Juang, J. Y.
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Lin, J. -Y.
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Wu, K. H.
;
Uen, T. M.
Two different types of nonlinear current-voltage characteristics are observed in oxygen-deficient La(0.67)Ca(0.33)MnO(3-y) (LCMO) films at temperatures below the insulator-metal transition. The paraboliclike dynamic conductance G(V), defined as dI/dV, curves near the zero bias observed in highly oxygen-deficient LCMO films implies the contribution from the spin-dependent tunneling transport between ferromagnetic clusters, with magnetic-disordered regions serving as tunneling barriers. On the other hand, for the slightly oxygen-deficient LCMO films, dips around the zero bias were observed in nonlinear G(V) curves and have been attributed to spin-flip scattering, with oxygen vacancies serving as scattering centers. (C) 2008 American Institute of Physics.
4-Port polarization-independent wavelength-interleaving bidirectional circulator
(2008-01-15)
Hsieh, Po-Jen
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Chen, Jing-Heng
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Hsieh, Hung-Chih
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Jian, Zhi-Cheng
;
Su, Der-Chin
This study develops an alternative type of 4-port polarization-independent wavelength-interleaving bidirectional circulator. In this circulator the even- and odd-channels circulate with opposite handedness regardless of the state of polarization of signals. It has a pair of orthogonal holographic spatial- and polarization modules (HSPMs) and a Lyot-Ohman filter (LOF). Each HSPM has two holographic spatial walk-off polarizers (HSWPs), two glass plates and two half-wave plates. The function of the HSWJP is firstly described. Next, the structures and the operating principles of the HSPM and the LOF are also described. Then, the operating principle and the performance of this circulator are discussed. It has such merits as polarization-independence, compactness, high isolation, lack of polarization mode dispersion and ease of fabrication. (c) 2007 Elsevier B.V. All rights reserved.
管管作品兩首
(2008-01-15)
管管
A variables sampling plan based on C-pmk for product acceptance determination
(2008-01-16)
Wu, Chien-Wei
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Pearn, W. L.
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工業工程與管理學系
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Department of Industrial Engineering and Management
Process capability indices are useful management tools, particularly in the manufacturing industry, which provide common quantitative measures on manufacturing capability and production quality. Most supplier certification manuals include a discussion of process capability analysis and describe the recommended procedure for computing a process capability index. Acceptance sampling plans have been one of the most practical tools used in classical quality control applications. It provides both vendors and buyers to reserve their own rights by compromising on a rule to judge a batch of products. Both sides may set their own safeguard line to protect their benefits. Two kinds of risks are balanced using a well-designed sampling plan. In this paper, we introduce a new variables sampling plan based on process capability index C-pmk to deal with product sentencing (acceptance determination). The proposed new sampling plan is developed based on the exact sampling distribution hence the decisions made are more accurate and reliable. For practical purpose, tables for the required sample sizes and the corresponding critical acceptance values for various producer's risk, the consumer's risk and the capability requirements acceptance quality level (AQL), and the lot tolerance percent defective (LTPD) are provided. A case study is also presented to illustrate how the proposed procedure can be constructed and applied to the real applications. (C) 2006 Elsevier B.V. All rights reserved.
Surface modified gold nanowires for mammalian cell transfection
(2008-01-16)
Kuo, Chiung-Wen
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Lai, Jun-Jung
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Wei, Kung Hwa
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Chen, Peilin
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材料科學與工程學系
Aminothiol modified gold nanowires have been used as vectors for the delivery of plasmid DNA into two different types of mammalian cells: 3T3 and HeLa. It was measured that positively charged gold nanowires with a diameter of 200 nm and a length around 5 mu m were capable of carrying 1 pg of plasmid DNA per nanowire into cells. Compared with other transfection reagents, the gold nanowires exhibited the highest transfection efficiency while almost no cytotoxicity was observed. In addition, it has been shown that individual nanowires can be visualized with sub-micrometer resolution, which may allow the use of functionalized multi-segment nanowires as local probes for the investigation of the microenvironment inside cells.
以結合半準位信號及多階層錯誤編碼的光碟防盜拷方法
(2008-01-16)
高銘盛
;
廖晨吟
;
葉人瑋
一種以結合半準位信號及多階層錯誤編碼的光碟防盜拷方法,本發明之方法是先於光碟設有加密鍵,再以設於光碟導入區之半準位信號及多階層錯誤編碼保護該加密鍵,使該加密鍵被正確解復之機率曲線產生明顯截止現象,達到防制盜拷之功效,而截止現象是依一定範圍之反射率而判斷。本發明係為一種低成本及防制各種方式盜拷之方法,並解決習用0位元與1位元被輕易複製的問題,且適用於一般播放器,不需複雜的配備及精密的檢測電路。
基板排序派工之方法
(2008-01-16)
巫木誠
;
陳德珊
本發明係揭露一種基板排序派工之方法,此方法包含提供卡匣配對關係、基板配對關係及排序機,並設置有輸入埠及輸出埠,且依據卡匣配對關係經演算法產生派工序列,將複數個第一卡匣依派工序列配送至輸入埠,且第一卡匣中的複數個第一基板,藉由排序機之機械手臂依基板配對關係移動與特定第二卡匣配對者至輸出埠,產出與第二卡匣內複數個第二基板完全配對的複數個第三卡匣,並將已配對的第二、第三卡匣送入壓合機進行壓合,藉此派工序列縮短第三卡匣產出時程,提昇壓合機之產能利用率。
Soluble phenanthrenyl imidazole for photo-electrical conversion of solar cell
(2008-01-17)
Wei, Kung-Hwa
;
Chang, Yao-Te
A novel material of phenanthrenyl imidazole is applied to a solar cell. A phenanthrenyl-imidazole moiety is introduced to reduce a power band of a polymer, so that a photocurrent and an optoelectrical transformation efficiency are improved. Thus, a polymer having the novel material is very suitable to be used in a solar cell to acquire a high optoelectrical transformation efficiency.
GaInP/GaAs HBT wideband transformer Gilbert downconverter with low voltage supply
(2008-01-17)
Tseng, S. -C.
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Meng, C. C.
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Wu, C. -K.
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電信工程研究所
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Institute of Communications Engineering
A low-voltage wideband downconverter along with an integrated transformer RF balun using the 2 mu m GaInP/GaAs HBT technology is demonstrated. This transformer is a symmetric type and plays a role as a single-to-differential balun. Without the parasitic between the transformer and the substrate, the transformer can work at higher frequencies. This transformer downconverter operates from 1.5 to 14 GHz with around 20 dB conversion gain and 1.8 GHz IF 3 dB bandwidth. The frequency range of the mixing operation is wide and covers the digital video broadcasting via satellite (DVB-S) bands. This mixer is therefore useful for DVB-S applications.
Illuminance formation and color difference of mixed-color light emitting diodes in a rectangular light pipe: an analytical approach
(2008-01-20)
Cheng, Chu-Ming
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Chern, Jyh-Long
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光電工程學系
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Department of Photonics
We developed an analytical method of illuminance formation for mixed-color LEDs in a rectangular light pipe in order to derive American National Standards Institute (ANSI) light uniformity, ANSI color uniformity, and color difference of light output using photometry, nonimaging, and colorimetry. The analytical results indicate that the distributions of illuminance and color difference vary with different geometric structures of light pipes and the location of the light sources. It was found that both the ANSI light and the ANSI color uniformity on the exit plane of the light pipe are reduced exponentially with the increase in length of the light pipe. It is evident that a length scale L/A greater than unity assures that the mixed-color LED sources on the entrance plane are uniformly illuminated with acceptable uniform brightness and color on the exit plane of the rectangular light pipe, where L is the length of the light pipe, and A is a constant, which is a geometric parameter for the scale unit of the light pipe's input face. Furthermore, the ANSI light uniformity can be minimized, and the ANSI color uniformity can be maximized under the condition of multilight-source locations P = Q = +/- A/4, where P and Q are the coordinates along the long axis and the short axis, respectively, with one being the entrance plane of the light pipe. We can conclude that the optimum form factor of the light pipe is a square shaped cross section, with the length scale L/A being equal to unity and with multilight sources located individually on positions of A/4 in order to achieve very uniform illuminations with the highest light efficiency and compact package for the optical system with mixed-color LEDs, where L is the length of the light pipe. (C) 2008 Optical Society of America.
Carrier-mediated exchange coupling and fermi surface topology
(2008-01-20)
Huang, Wen-Min
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Lai, Hsin-Hua
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Chang, Cheng-Hung
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Lin, Hsiu-Hau
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物理研究所
We investigate the carrier-mediated exchange coupling between two ferromagnets, sandwiching an intermediate thin layer with Rashba interaction. The effective exchange coupling is obtained by integrating out the itinerant carriers. It turns out that the magnetic trends depend sensitively upon the topology of the Fermi surface. As the topology changes from "wedding cake" to "donut", the mediated exchange goes from the oscillatory Ruderman-Kittel-Kasuya-Yosida to the non-collinear spiral interactions accordingly. It is rather surprising that the Fermi surface topology determines which type of magnetic interaction becomes dominant. Finally, we also discuss potential applications for carrier-mediated exchange coupling across the junction.
The cutoff phenomenon for ergodic Markov processes
(2008-01-20)
Chen, Guan-Yu
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Saloff-Coste, Laurent
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應用數學系
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Department of Applied Mathematics
We consider the cutoff phenomenon in the context of families of ergodic Markov transition functions. This includes classical examples such as families of ergodic finite Markov chains and Brownian motion on families of compact Riemannian manifolds. We give criteria for the existence of a cutoff when convergence is measured in L(p)-norm, 1 < p < infinity. This allows us to prove the existence of a cutoff in cases where the cutoff time is not explicitly known. In the reversible case, for 1 < p <= infinity, we show that a necessary and sufficient condition for the existence of a max-L(p) cutoff is that the product of the spectral gap by the max-L(p) mixing time tends to infinity. This type of condition was suggested by Yuval Peres. Illustrative examples are discussed.