Browsing by Issue Date, starting with "2006-05-25"

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Extrusion analysis and workability prediction of three-layer composite hexagonal clad rods
(2006-05-25)
Wu, CW
;
Hsu, RQ
;
機械工程學系
;
Department of Mechanical Engineering
This study uses upper bound method to predict the workability for the extrusion of three-layer composite hexagonal clad rods. A velocity field is generated with the assistance of a product's cross-section profile functions. The velocity component in the extrusion axis is expressed as a convex distribution. The simultaneous deformation of each constituent material with quite different mechanical properties may lead to fracture. A criterion for fracture based on the velocity deviation existing on the layer interface was proposed. Material fractures under extrusion are affected by a set of independent process parameters, including the initial area percentage of each layer, friction condition of die, mechanical characteristics of three constituent materials and reduction of area of billet. Finally, figures of extrusion limits containing safety and fracture zones for each process parameter are obtained for extrusion of three-layer composite hexagonal clad rods. (c) 2006 Elsevier B.V. All rights reserved.
Comment on "Atomistic view of the recombinative desorption of H-2 from H/Si(100)" - Reply
(2006-05-26)
Lin, DS
;
Chiang, TC
;
物理研究所
;
Institute of Physics
與世界在管管裡重逢,讀管管詩畫集《腦袋開花》
(2006-05-28)
鴻鴻
Polymer space-charge-limited transistor
(2006-05-29)
Chao, YC
;
Meng, HF
;
Horng, SF
;
物理研究所
;
電子工程學系及電子研究所
A metal grid is sandwiched between poly(3-hexylthiophene) to form a solid-state version of vacuum tube triode, where the vertical space-charge-limited current is modulated by the grid potential. The Al grid contains random submicron openings formed by a nonlithographic method. The multilayer polymer structure is made by spin coating. The operating voltage of the polymer space-charge-limited transistor is 3 V, and the current gain of 506 is obtained. The characteristics of the transistor can be tuned by the diameters and the density of the openings on the grid. Similar to the vacuum tube triode, the current follows a power law voltage dependence.
Analytical technique for simplification of the encoder-decoder circuit for a perfect five-qubit error correction
(2006-05-30)
Hsieh, JY
;
Li, CM
;
Chuu, DS
;
電子物理學系
;
Department of Electrophysics
Simpler encoding and decoding networks are necessary for more reliable quantum error-correcting codes (QECCs). The simplification of the encoder-decoder circuit for a perfect five-qubit QECC can be derived analytically if the QECC is converted from its equivalent one-way entanglement purification protocol. In this work, the analytical method to simplify the encoder-decoder circuit is introduced and a circuit that is as simple as the existing simplest circuits is presented as an example. The encoder-decoder circuit presented here involves nine single- and two-qubit unitary operations, only six of which are controlled-NOT gates.
Synthesis and characterization of rod-coil polymers based on poly(ethylene oxide)s sand novel luminescent aromatic cores
(2006-05-30)
Lin, HC
;
Lee, KW
;
Tsai, CM
;
Wei, KH
;
材料科學與工程學系
A novel conjugated aromatic core containing direct-coupled fluorene, thiophene, and biphenyl groups via Suzuki coupling reaction was synthesized. The asymmetrical molecules contain two kinds of poly( ethylene oxide)s (PEO, M-n = 750 and 2000, n = 17 and 44) on one side of the rigid cores. Asymmetrical FOC8PEO17 and FOC16PEO17 contain flexible PEO chains (n = 17) displaying the smectic phases. However, FOC8PEO44 and FOC16PEO44 consisting of flexible PEO chains ( n = 44) exhibit two kinds of columnar phases, Col(h) and Col(r). Besides, alkoxy groups with different lengths (- OC(8)H(17)and - OC16H33) on both sides of the rigid cores were used as another flexible chain to form symmetrical molecules. Symmetrical FOC8 and FOC16 exhibit the nematic and smectic mesophases, respectively. Optical textures (POM) and XRD patterns have confirmed the structure of the mesophases and the molecular arrangements. The photophysical characteristics of all luminescent compounds were studied by photoluminescence and UV-vis absorption. In addition, a series of double-layered PLED devices with the configuration of PVK: emitters( 100: 8 by weight)/TPBI/MgAg/Ag were fabricated and investigated.
Welding flux for use in arc-welding of stainless steels, method of welding stainless steel members using the welding flux
(2006-05-30)
Chou
;
Chang-Pin
;
Huang
;
Her-Yueh
;
Shyu
A welding flux for use in welding stainless steel parts to increase welding penetration, consisting essentially a base material obtained from manganese peroxide (MnO2), and an activator selected from a material group that includes zinc oxide (ZnO), silicon dioxide (SiO2), chromium oxide (CrO2), titanium dioxide (TiO2), molybdenum dioxide (MoO2), and iron oxide (Fe2O2).
Dynamic multicast routing under delay constraints in WDM networks with heterogeneous light splitting capabilities
(2006-05-31)
Chen, MT
;
Tseng, SS
;
Lin, BMT
;
資訊工程學系
;
資訊管理與財務金融系註：原資管所+財金所
Because optical WDM networks will be realized as network backbone in the near future, multicasting in WDM networks needs to be supported for various network applications. In this paper, we propose a new dynamic multicast routing problem under delay constraints (DMR-DC) for finding an optimal light-forest with the minimum multicast cost from these links with available wavelengths for routing a multicast request that arrives in random with a given delay bound in a WDM network with heterogeneous light splitting capabilities, where a light-forest is a set of light-trees used to set up switches to route the request. Multicast cost is defined by communication cost ratio and wavelength consumption ratio. The problem is to determine a light-forest with less wavelength consumption and less communication cost. This problem is NP-hard because it can be reduced from the minimum Steiner tree problem. In this paper, we propose an efficient three-phase (generation, refinement, and conversion) solution model to find approximate solutions in a reasonable time. (C) 2005 Elsevier B.V. All rights reserved.
Synthesis and characterization of polybenzoxazine networks nanocomposites containing multifunctional polyhedral oligomeric silsesquioxane (POSS)
(2006-05-31)
Lee, Yuan-Jyh
;
Kuo, Shiao-Wei
;
Huang, Chih-Feng
;
Chang, Feng-Chih
;
應用化學系
A new class of polybenzoxazine/POSS nanocomposites with network structure is prepared by reacting multifunctional benzoxazine POSS (MBZ-POSS) with benzoxazine monomers (Pa and Ba) at various compositional ratios. Octafunctional cubic silsesquioxane (MBZ-POSS) is used as a curing agent, which is synthesized from eight organic benzoxazine tethers through hydrosilylation of vinyl-terminated benzoxazine monomer (VP-a) with octakis(dimethylsiloxy)silsesquioxane (Q(8)M(8)(H)) using a platinum complex catalyst (Pt-dvs). Incorporation of the silsesquioxane core into polybenzoxazine matrix could significantly hinder the mobility of polymer chains and enhance the thermal stability of these hybrid materials. For these nanocomposites, increasing the POSS content in the hybrids is expected to improve its thermal properties with respect to the neat polybenzoxazine. The morphology feature is useful to explain the thermal property changes (T-g and T-d) and AFM images show that the presence of POSS aggregation in larger scales occurs at higher POSS contents. The reason of the heterogeneous phase separation may be from the less compatibility of the inorganic silsesquioxane core with organic benzoxazine species and the homopolymerization of MBZ-POSS. In the course of the formation of the polybenzoxazine/POSS hybrids, POSS particles were separated from the polybenzoxazine rich region, leading to POSS rich domains in the range of 50-1000 nm. (c) 2006 Elsevier Ltd. All rights reserved.
Stable new bound soliton pairs in a 10 GHz hybrid frequency modulation mode-locked Er-fiber laser
(2006-06-01)
Hsiang, WW
;
Lin, CY
;
Lai, YC
;
光電工程學系
;
Department of Photonics
We report what is, to our knowledge, the first experimental observation of stable new bound soliton pairs at the 10 GHz repetition rate in a hybrid FM harmonic mode-locked Er-fiber laser (1177 soliton pairs simultaneously in the laser cavity). The two solitons in the soliton pair have the identical pulse shape and are with the antiphase (pi phase difference). Their time separation is about three times the FWHM soliton width and varies with the phase modulation strength. The corresponding mechanism for explaining the formation as well as the superior stability of these closely bound soliton pairs is also given. (c) 2006 Optical Society of America.
個人電腦之麥克風陣列系統
(2006-06-01)
胡竹生
;
鄭价呈
;
康創閔
;
劉維瀚
本發明係為一個人電腦之麥克風陣列系統，其利用通用串列匯流排資料擷取系統將類比聲音訊號放大並通過一帶通濾波器，最後將之轉換成數位聲音訊號，再利用語音訊號增強系統將擷取到之數位聲音訊號中聲音雜訊部分加以抑制並純化成一語音訊號，其整套系統具有低成本、便利性、擴充性及高彈性等優點，可在吵雜及回音存在的環境下消除非語音雜訊，且可根據語者方位、環境及器材的變動自行調整參數，以達到自動化高效能之語音純化效果。
Fabrication of a flexible and disposable microreactor using a dry film photoresist
(2006-06-01)
Tsai, Yuan-Chien
;
Yang, Shung-Jim
;
Lee, Hsun-Tsing
;
Jen, Hsiu-Ping
;
Hsieh, You-Zung
In this paper, we demonstrate that a low-cost flexible microreactor can be manufactured using a dry film photoresist in conjunction with photolithographic and hot roll lamination techniques. A microfluidic flow path and sample reservoir patterns were prefabricated in a dry film photoresist tape using traditional photolithographic methods. This tape was sandwiched between two plastic films - wells were prepouched on the cover film - that were bonded upon passage through a hot roll laminator. A simple Plexiglas reactor holder was designed and constructed to use in evaluating the flexible microchip reactor. We demonstrate a chemical synthesis of polyaniline that was performed with this polymeric microreactor using a hydrodynamic flow control system. The fabrication of this microreactor suggests that there is great potential for designing and prototyping disposable microscale reaction systems using dry film photoresist for a range of chemical and biochemical syntheses.
Agility evaluation using fuzzy logic
(2006-06-01)
Lin, CT
;
Chiu, H
;
Tseng, YH
;
管理科學系
;
Department of Management Science
"Change" seems to be one of enterprises' major characteristics in this new competitive era. Agile enterprise whereby an organization can change and adapt quickly to changing circumstances is increasingly viewed as a winning strategy. However, in embracing agile enterprise, there are important questions to be asked: what precisely is agility and how can it be measured? How can one assist in achieving and enhancing agility effectively? Answers to such questions are critical to the practitioners and to the theory of agile enterprise design. The foundation of agile enterprise lies in the integration of information system/technologies, people, business processes and facilities. Due to the ill-defined and vague indicators which exist within agility assessment, most measures are described Subjectively by linguistic terms which are characterized by ambiguity and multi-possibility, and the conventional assessment approaches cannot suitably nor effectively handle such measurement. However, fuzzy logic provides a useful tool for dealing with decisions in which the phenomena are imprecise and vague. Thus, the novelty in the paper is development of the absolute agility index, a unique and unprecedented attempt in agility measurement, using fuzzy logic to address the ambiguity in agility evaluation. Details of the approach and a framework of a fuzzy agility evaluation will be presented. An example is also used to illustrate the approach developed. (c) 2005 Elsevier B.V. All rights reserved.
Effect of atomic geometry on shot noise in aluminum quantum point contacts
(2006-06-01)
Yao, J.
;
Chen, Y. -C.
;
Di Ventra, M.
;
Yang, Z. Q.
;
電子物理學系
We investigate the role of atomic geometry on shot-noise properties of aluminum atomic contacts using first-principles calculations. We study both the effect of atomic separation in the wire as well as the geometry of the contacts. We find that shot noise, as opposed to conductance, is very sensitive to atomic details. In particular, the Fano factor for the asymmetric contact structures is more than double that of the symmetric ones due to increased backscattering, and is within the experimental range. These results indicate that shot noise may be used as a tool to infer the atomic geometries of quantum point contacts.
Identifying a design management package to support concurrent design in building wafer fabrication facilities
(2006-06-01)
Dzeng, RJ
;
土木工程學系
;
Department of Civil Engineering
Concurrent design is commonly used in building a semiconductor wafer fabrication facilities to shorten projects. Current practice in managing a design schedule involves preset milestones that represent percentages of completion. Such a simple control scheme does not provide sufficient information to support concurrent design. This study presents an analytical model that applies a cluster identification algorithm to separate the work of designing a multisystem project into management packages that support concurrent design. Tasks within a package have strong informational dependency relationships on each other, and are not suited for concurrent design. Tasks of different packages have weak dependency relationships on each other, and are suited for concurrent design. Tendering design work based on these packages may reduce the number of design interfaces between participating design firms. Possible application of the model includes the management of design schedule, design contract tendering, and design information flow.
Dual-bandpass filters with serial configuration using LTCC technology
(2006-06-01)
Lin, KC
;
Chang, CF
;
Wu, MC
;
Chung, SJ
;
電信工程研究所
A dual-bandpass filter that utilizes a serial configuration of the inductive coupled-line (ICL) filter and the capacitive coupled-line (CCL) filter is investigated in this study. Numerical analysis is presented for the difference between the ICL and CCL filters. The dual-bandpass filter has a similar behavior to the individual single-band filter around the corresponding passband. An extra transmission zero can be generated between the two pass-bands of the dual-bandpass filter in that the ICL and CCL filters exhibit an out-of-phase response. Four architectures of dual-bandpass filters are proposed for the 2.4/5-GHz systems. Two of them are demonstrated by the low-temperature co-fired ceramic multilayer technology. Measurements results agree quite well with the simulation ones.
Repairing of etching-induced damage of high-k Ba0.5Sr0.5TiO3 thin films by oxygen surface plasma treatment
(2006-06-01)
Tsai, Kou-Chiang
;
Wu, Wen-Fa
;
Chao, Chuen-Guang
;
Lee, Jain-Tsai
;
Hsu, Jwo-Lun
Ba0.5Sr0.5TiO3 (BST) thin films were patterned for fabricating BST capacitors in a helicon-wave plasma system. The optimization conditions were an Ar (80%)/Cl-2 (20%) gas mixture with a helicon-wave plasma power and a substrate bias rf power of 1500 and 90 W, respectively. From results of X-ray photoelectron spectroscopy, physical ion bombardment is more effective than chemical reaction for removing Sr, while Ti can be removed by the formation of volatile TiClx. Ba was primarily removed by chemically assisted physical etching (such as that using BaClx) Some etching residues consisting of Ba and Sr were found after the BST films were etched and increased leakage current density. Oxygen surface plasma treatment can effectively repair surface damage caused by etching, and it reduced the leakage current density of the BST capacitor from 4.0 x 10(-7) to 3.0 x 10(-8) A/cm(2) at 1 MV/cm and increased the breakdown field to similar to 2 MV/cm at 1.0 x 10(-6) A/cm(2).
Doped poly(methyl methacrylate) photopolymers for holographic data storage
(2006-06-01)
Lin, Shiuan Huei
;
Lin, June-Hua
;
Chen, Po-Lin
;
Shiao, Yi -Nan
;
Hsu, Ken Y.
In this paper, we report our investigations on thick holographic recording material of the phenanthrenequinone doped poly(methyl methacrylate) (PQ:PMMA) photopolymer. The design strategy and fabrication technique for making thick polymer samples with negligible shrinkage and good optical quality are presented. The physical mechanism for holographic recording in PQ:PMMA material is described, and methods for improving are proposed. Based on these methods, photopolymer samples with different compositions are fabricated and experimentally characterized. The results show that by modifying compositions, the material sensitivity and dynamic range for volume holographic recording have been improved.
HfAlON n-MOSFETs incorporating low-work function gate using ytterbium silicide
(2006-06-01)
Wu, CH
;
Hung, BF
;
Chin, A
;
Wang, SJ
;
Yen, FY
The authors have fabricated low-temperature fully silicided YbSi2-x-gated n-MOSFETs that used an HfAION gate dielectric with a 1.7-nm EOT. After a 600 degrees C rapid thermal annealing, these devices displayed an effective work function of 4.1 eV and a peak electron mobility of 180 cm(2)/V(.)s. They have additional merit of a process compatible with current very large scale integration fabrication lines.
Direct observation of structure effect on ferromagnetism in Zn1-xCoxO nanowires
(2006-06-01)
Jian, WB
;
Wu, ZY
;
Huang, RT
;
Chen, FR
;
Kai, JJ
Diameter-controllable single-crystalline ZnO nanowires (NWs), with the [0001] growth direction in the plane, have been fabricated by using thermal evaporation method. The as-grown NWs with diameters of similar to 40 nm were implanted with various amounts of Co ions. These Zn1-xCoxO (x <= 0.11) NWs possessed a high density of bombardment-induced orientation variations and stacking faults, and exhibited paramagnetic behavior. After thermal annealing, the structural defects largely disappeared and noticeable hysteresis in the magnetization loops were observed, indicating the presence of apparent ferromagnetic ordering in the NWs. This result provides important insight into the role played by defects in relation to the occurrence of ferromagnetism in diluted magnetic semiconductor NWs.