Browsing by Issue Date, starting with "2012-03-29"

Now showing 1 - 20 of 36951

Wideband high-isolation and perfect-balance microstrip rat-race coupler
(2012-03-29)
Chang, W. S.
;
Liang, C. H.
;
Chang, C. Y.
;
電信工程研究所
;
Institute of Communications Engineering
A microstrip rat-race coupler with high isolation and perfect balance is presented. By modifying March's rat-race coupler with two additional short-circuited stubs, the isolation and the amplitude/phase balance of the proposed coupler improve significantly. The circuit can be easily fabricated on a single-layer substrate using the conventional printed circuit board process.
Reversible Hydrophobic/Hydrophilic Adhesive of PS-b-PNIPAAm Copolymer Brush Nanopillar Arrays for Mimicking the Climbing Aptitude of Geckos
(2012-03-29)
Chen, Jem-Kun
;
Wang, Jing-Hong
;
Fan, Shih-Kang
;
Chang, Jia-Yaw
;
材料科學與工程學系
Inspired by the adjustable adhesive ability of the gecko foot pad, alternately attaching to and detaching from where they climb, we used a fabrication process to generate well-defined pillar patterns of polymerized styrene and successively grafted n-isopropylacrylamide (NIPAAm) as thermally responsive terminating of the pillars. By varying the geometry of the patterns including aspect ratio and duty ratio (solid fraction), the respective roles of the geometry the pattern features on the static water contact angle (WCA), hysteresis, adhesive, and friction force at 25 and 50 degrees C have been systemically investigated. The fabrication strategy exploits surface textures of polystyrene (PS) and thermally responsive terminating of PNIPAAm as the artificial foot pad surface, which could generate alternately ca. 93.9 and 8.7 nN of adhesive force at 25 and 50 degrees C, respectively. The results indicate that the adjustable adhesive ability of the copolymer brushes could approach the climbing aptitude of a gecko much more closely. We develop a bioinspired artificial analog by using two common methods including atom-transfer radical polymerization (ATRP) and photolithography to adjust adhesion reversibly on a silicon surface. The advantage of the processing strategy described here is the potential to fabricate a device of an artificial foot pad to mimic the climbing aptitude of geckos vividly.
Possible lattice approach to B -> D pi (K) matrix elements
(2012-03-29)
Aubin, Christopher
;
Lin, C. -J. David
;
Soni, Amarjit
;
物理研究所
;
Institute of Physics
We present an approach for computing the real parts of the nonleptonic B -> DP and B -> (D) over barP (P = K. pi) decay amplitudes by using lattice QCD methods. While it remains very challenging to calculate the imaginary parts of these matrix elements on the lattice, we stress that their real parts play a significant role in extracting the angle gamma in the b-d unitarity triangle of the CKM matrix. The real part on its own gives a lower bound to the absolute magnitude of the amplitude which is in itself an important constraint for determining gamma. Also the relevant phase can be obtained by using B decays in conjunction with relevant charm decay data. Direct four-point function calculations on the lattice, while computationally demanding, do yield the real part as that is not impeded by the Maiani-Testa theorem. As an approximation, we argue that the chiral expansion of these decays is valid in a framework similar to that of hard-pion chiral perturbation theory. In addition to constructing the leading-order operators, we also discuss the features of the next-to-leading order chiral expansion. These include the contributions from the resonance states, as well as the generic forms of the chiral logarithms. (C) 2012 Elsevier B.V. All rights reserved.
Solar cell apparatus having the transparent conducting layer with the structure as a plurality of nano-level well-arranged arrays
(2012-03-29)
Tseng Ping-Chen
;
Yu Peichen
;
Kuo Hao-Chung
The invention discloses an apparatus for enhancing light absorption of solar cells and photodetectors by diffraction. The invention comprises the structure as the plurality of nano-level well-arranged arrays with a plurality of certain defect areas including the shapes of rod, tapered-cone, and cone, which diffracts incident light to oblique angles for light trapping. Surface reflection can also be reduced for either broadband or narrow band spectral absorption. The increased contact area between the transparent conducting layer and photoactive layer is beneficial for current extraction, which increases the internal quantum efficiency (IQE).
Hybrid OFDM-based multi-band wireless and baseband signal transmission in PON access
(2012-03-29)
Yeh, C. H.
;
Chow, C. W.
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Chen, H. Y.
;
Sung, J. Y.
;
光電工程學系
A hybrid OFDM-baseband (BB) signal and three-band OFDM wireless channels using the 2.5 GHz bandwidth directly modulated laser and 10 GHz bandwidth electroabsorption modulated laser in a passive optical network (PON) is investigated. Each 16-QAM OFDM wireless and 64-QAM OFDM-BB signals can achieve 11.2 and 15 Gbit/s traffic data rates, respectively, in 20 km fibre transmissions. Moreover, the network performance has also been analysed and discussed.
Stretched Contact Printing of One-Dimensional Nanostructures for Hybrid Inorganic-Organic Field Effect Transistors
(2012-03-29)
Hsieh, Gen-Wen
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Wang, JinJin
;
Ogata, Ken
;
Robertson, John
;
Hofmann, Stephan
We demonstrate a stretched contact printing technique to assemble one-dimensional nanostructures with controlled density and orientation from either dry or wet sources. The random, chaotically arranged nanostructures can gradually transform to a highly aligned configuration. Our results show that up to 90% of the printed nanowires are aligned within +/- 15 degrees of the primary stretching direction. This approach is easily applicable to a variety of nanowires and nanotubes on different substrates, and we demonstrate various field effect transistors with nanowire and hybrid nanowire-polymer networks. The hybrid inorganic-organic transistors based on a parallel aligned nanowire network and a semiconducting polymer revealed a significant enhancement in transistor mobility, a 10-fold reduction in subthreshold slope (similar to 0.26 V decade(-1)), and superior air stability compared to a pristine polymer host.
Formation, Dissolution, and Transfer Dynamics of a Millimeter-Scale Thin Liquid Droplet in Glycine Solution by Laser Trapping
(2012-03-29)
Yuyama, Ken-ichi
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Rungsimanon, Thitiporn
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Sugiyama, Teruki
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Masuhara, Hiroshi
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應用化學系
The formation, dissolution, and transfer of a millimeter-scale dense liquid droplet are demonstrated by focusing a CW near-infrared laser beam into a thin film of glycine solution in heavy water. The entire process is investigated by directly monitoring the temporal change in the two-dimensional surface profile using a laser displacement meter. Upon laser irradiation, the surface depression is initially induced by laser heating, followed by the formation of the shallow convex-shaped droplet around the focal spot, in which the droplet is always in contact with the surrounding solution through the ultrathin solution layer. After the laser is switched off, the dissolution occurs through the recovery from the ultrathin layer toward the original solution film. When the laser is set to the outside of the droplet, the solution depression is similarly induced, and subsequently the droplet starts moving toward the focal spot. These processes are summarized and discussed in view of laser-induced effects of concentration increase and temperature elevation.
Influence of microstructure and its evolution on the mechanical behavior of modified MAR-M247 fine-grain superalloys at 871 degrees C
(2012-03-30)
Liao, Jian-Hong
;
Bor, Hui-Yun
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Wei, Chao-Nan
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Chao, Chuen-Guang
;
Liu, Tzeng-Feng
This study added Re to Mar-M247 fine-grain superalloy and investigated the influence of microstructure and its evolution on the mechanical behavior at 871 degrees C. Mar-M247 and modified Mar-M247 alloys consisted of dual precipitation of primary and secondary gamma' particles in the gamma matrix. An increase in Re content led to a reduction in the primary gamma' phase with the gamma' phase becoming finer; however, the addition of Re did not have an obvious influence the secondary gamma' phase. Tensile and creep tests (871 degrees C/379 MPa) showed that both tensile and creep strength increased with an increase in Re content up to a maximum of 3 wt%. In the early creep stage, the addition of Re improved creep resistance by increasing the strength of the gamma matrix and decreasing the inter-particle spacing. In the later creep stage, the linear fraction of the gamma' raft in stress axial direction increased following the addition of Re, resulting in improved creep resistance. Observation of microstructure evolution indicated that only secondary gamma' phase coarsened directionally into a rafting structure and the primary gamma' phase was unaffected by creep. An interrupted creep tests verified that the gamma' rafting structure initiated in the primary creep stage and completed in the secondary creep stage. The addition of excessive quantities of Re, such as 5 wt%, resulted in the formation of needle-like P phase, which damaged the tensile and creep properties. During tensile and creep tests, cracks initiated and propagated along grain boundary (GB) in alloys containing 0-3 wt% Re; and propagated along both the GB and P/gamma interface in an alloy containing 5 wt% Re. In conclusion, optimal results were obtained for fine-grain Mar-M247 following the addition of 3 wt% Re. (C) 2012 Elsevier B.V. All rights reserved.
Understanding innovation performance and its antecedents: A socio-cognitive model
(2012-04-01)
Wang, Rong-Tsu
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Lin, Chieh-Peng
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經營管理研究所
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Institute of Business and Management
Little attention in the previous literature has been paid to understanding employees' factors that drive customer development knowledge and performance from the perspective of social psychology. Drawing on social cognitive theory, this study validates a research model that examines the above issue. In the setting of new product development across high-tech firms in Taiwan, this study postulates that innovation self-efficacy, role conflict, and role ambiguity influence innovation performance directly and indirectly via the mediation of customer knowledge development and innovation outcome expectation. This study contributes to the social science literature by applying social cognitive theory to the rarely explored area of innovation performance and by presenting an operationalization of role stressors (i.e., role ambiguity and role conflict) in the area. Lastly, managerial implications and limitations from the empirical findings are provided. (C) 2012 Elsevier BM. All rights reserved.
Diagnosability of star graphs with missing edges
(2012-04-01)
Chiang, Chieh-Feng
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Hsu, Guo-Huang
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Shih, Lun-Min
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Tan, Jimmy J. M.
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資訊工程學系
In this paper, we study the system diagnosis on an n-dimensional star under the comparison model. Following the concept of local diagnosability [3], the strong local diagnosability property [7] is discussed; this property describes the equivalence of the local diagnosability of a node and its degree. We prove that an n-dimensional star has this property, and it keeps this strong property even if there exist n - 3 missing edges in it. (C) 2011 Elsevier Inc. All rights reserved.
Development of biosensor for serine/threonine kinases
(2012-04-01)
Lee, Jhao-hong
;
Yuan, Chiun-Jye
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生物科技學系
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分子醫學與生物工程研究所
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Department of Biological Science and Technology
國片談
(2012-04-01)
陳奕儒
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Department of Communication and Technology
;
傳播與科技學系
2008年夏末的某個夜晚，天氣開始略帶一點秋涼，當時剛升上水深火熱的高三，筆者一邊算著數學，一邊聽著收音機播著曲子。每當電台進入廣告或音樂結束的時候，筆者都習慣性切換其他電台來聽，但那時候可能念書念到廢寢忘食，等回神過來，陳為民已經開始用他獨特的聲嗓在主持節目。
一種於太陽能電池裝置內形成透明光捕捉結構的方法
(2012-04-01)
蔡娟娟
;
徐振航
本發明揭露一種於太陽能電池裝置內形成透明光捕捉結構的方法，首先形成一層或多層透明薄膜於透明基板上，並藉由製程方法形成具有光捕捉層結構，接著再形成透明導電氧化物層於該光捕捉層上，續形成薄膜太陽能電池單元及薄透明導電氧化層，最後形成金屬電極層於薄透明導電氧化層上，藉以完成該於太陽能電池裝置內形成透明光捕捉結構的方法。
Synchronized oscillations in a mathematical model of segmentation in zebrafish
(2012-04-01)
Liao, Kang-Ling
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Shih, Chih-Wen
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Tseng, Jui-Pin
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應用數學系
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Department of Applied Mathematics
Somitogenesis is a process for the development of somites which are transient, segmental structures that lie along the anterior-posterior axis of vertebrate embryos. The pattern of somites is governed by the segmentation clock and its timing is controlled by the clock genes which undergo synchronous oscillation over adjacent cells in the posterior presomitic mesoderm (PSM). In this paper, we analyze a mathematical model which depicts the kinetics of the zebrafish segmentation clock genes subject to direct autorepression by their own products under time delay, and cell-to-cell interaction through Delta-Notch signalling. Our goal is to elucidate how synchronous oscillations are generated for the cells in the posterior PSM, and how oscillations are arrested for the cells in the anterior PSM. For this system of delayed equations, an iteration technique is employed to derive the global convergence to the synchronous equilibrium, which corresponds to the oscillation-arrested. By applying the delay Hopf bifurcation theory and the center manifold theorem, we derive the criteria for the existence of stable synchronous oscillations for the cells at the tail bud of the PSM. Our analysis provides the basic parameter ranges and delay magnitudes for stable synchronous, asynchronous oscillation and oscillation-arrested. We exhibit how synchronous oscillations are affected by the degradation rates and delays. Extended from the analytic theory, further numerical findings linked to the segmentation process are presented.
為自己發聲　獨立音樂市集
(2012-04-01)
鄭巧琪
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Department of Communication and Technology
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傳播與科技學系
台灣獨立音樂網站iNDIEVOX與誠品合作，結合創意市集與獨立音樂，召集幾十位獨立音樂人販售自己的作品。別具創意的獨立音樂市集，讓喜愛獨立音樂的樂迷可以知道更多創作人，也讓這些創作人有機會為自己發聲。
傳統戲曲的蛻變　現代意象
(2012-04-01)
林儀
;
Department of Communication and Technology
;
傳播與科技學系
傳統戲曲的表現形式包含了程式化的生旦淨丑四大角色，及配樂、唱詞、臉譜等元素，經過幾百年的演變，才成為今日我們所見的現代化的京劇，有了貼近觀眾的特殊審美經驗，且蘊含著廣大歷史洪流的痕跡與嘗試突破的新意。
去年夏天　我在六龜
(2012-04-01)
洪欣慈
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Department of Communication and Technology
;
傳播與科技學系
2011年夏天，透過平日課輔的學校主任介紹，我來到了充滿歷史的六龜育幼院。這是一個簡單卻處處充滿愛的地方，牆上、走廊，隨處可見的是小朋友的童年塗鴉及作品，陪伴了許多人成長，也孕育出許多夢想，但09年的八八風災，也讓此地遭受重創。
DEMATEL-based model to improve the performance in a matrix organization
(2012-04-01)
Wang, Wei-Chih
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Lin, Yueh-Hua
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Lin, Chia-Li
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Chung, Chu-Hsuan
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Lee, Ming-Tsung
Carrying out a design project for a high-tech facility requires a large amount of special knowledge in order to deal with the specific requirements from the client. Often the client forms a matrix organization, structured with several interrelated functional and project divisions to dictate the various requirements and needs. However, an ill-defined matrix organization is likely to result in late and inadequate decisions. This in turn may result in a poorly performing design. Identifying those divisions within the organization that perform poorly in the way they provide information for the project is critical. Therefore, this study proposes an innovative model to identify those divisions that may be responsible for the poor performance of the design project. The proposed model integrates the satisfied importance analysis (SIA) and the decision making trial and evaluation laboratory technique (DEMATEL). The SIA evaluates the performance of each division, while the DEMATEL captures the causal relationships among divisions to generate an influence-relations map. The proposed model is applied to a real-world high-tech facility design project in Taiwan to demonstrate the strengths of the model. (C) 2011 Elsevier Ltd. All rights reserved.
NADPH oxidase-derived superoxide Anion-induced apoptosis is mediated via the JNK-dependent activation of NF-kappa B in cardiomyocytes exposed to high glucose
(2012-04-01)
Tsai, Kun-Hsi
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Wang, Wei-Jan
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Lin, Cheng-Wen
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Pai, Peiying
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Lai, Tung-Yuan
Hyperglycemia-induced generation of reactive oxygen species (ROS) can lead to cardiomyocyte apoptosis and cardiac dysfunction. However, the mechanism by which high glucose causes cardiomyocyte apoptosis is not clear. In this study, we investigated the signaling pathways involved in NADPH oxidase-derived ROS-induced apoptosis in cardiomyocytes under hyperglycemic conditions. H9c2 cells were treated with 5.5 or 33 mM glucose for 36?h. We found that 33 mM glucose resulted in a time-dependent increase in ROS generation as well as a time-dependent increase in protein expression of p22phox, p47phox, gp91phox, phosphorylated I?B, c-Jun N-terminal kinase (JNK) and p38, as well as the nuclear translocation of NF-kB. Treatment with apocynin or diphenylene iodonium (DPI), NADPH oxidase inhibitors, resulted in reduced expression of p22phox, p47phox, gp91phox, phosphorylated I?B, c-Jun N-terminal kinase (JNK) and p38. In addition, treatment with JNK and NF-kB siRNAs blocked the activity of caspase-3. Furthermore, treatment with JNK, but not p38, siRNA inhibited the glucose-induced activation of NF-?B. Similar results were obtained in neonatal cardiomyocytes exposed to high glucose concentrations. Therefore, we propose that NADPH oxidase-derived ROS-induced apoptosis is mediated via the JNK-dependent activation of NF-B in cardiomyocytes exposed to high glucose. J. Cell. Physiol. 227: 1347-1357, 2012. (C) 2011 Wiley Periodicals, Inc.
Enhancement of PZT embedded swing arm actuator using integrated read/write performance and actuation
(2012-04-01)
Lin, Yu-Cheng
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Chou, Po-Chien
;
Cheng, Stone
;
機械工程學系
;
Department of Mechanical Engineering
The current technological challenges associated with the rotary-type seesaw arm actuator for small-form-factor (SFF) disk drives are the small skew focusing, which causes off-axis aberrations and reduces optical quality. This article develops a novel design for a seesaw arm actuator and suspension assembly that is based on a micro-PZT actuator to position pickup head. Dual-stage actuation relaxes the dynamic requirement on the focusing stroke. The proposed actuator with a tilt-compensation mechanism uses a PZT bender to drive pickup head focusing. This combined system, optical module and dual stage actuator, is effectively self-aligned the optical axis for read/write performance in both experiment and simulation result. Finite element modeling and dynamic measurements reveal significant improvements in the actuator bandwidth with and without micro-PZT actuator compensation.