Browsing by Issue Date, starting with "2014-05"

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Microtrenching-free two-step reactive ion etching of 4H-SiC using NF3/HBr/O-2 and Cl-2/O-2
(2014-05-01)
Tseng, Yuan-Hung
;
Tsui, Bing-Yue
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, the authors performed a reactive ion etch of a 4H-SiC substrate with a gas mixture of NF3, HBr, and O-2, resulting in a microtrenching-free etch. The etch rate was 107.8 nm/min, and the selectivity over the oxide hard mask was similar to 3.85. Cross-sectional scanning electron microscopy showed no microtrenching compared with etches using plasmas of NF3, NF3 /HBr, and NF3/O-2. Analyzing a variety of HBr/O-2 mixing ratios, the authors discuss the additive effect of each gas and their respective potential mechanisms for alleviating microtrenching. To increase the radius of gyration of the bottom corners, they introduced a second etch step with Cl-2/O-2 plasma. Fabricating simple metal-oxide-semiconductor capacitors on the two-step etched surface, the authors found that the electrical characteristics of the etched sample were nearly the same as the nonetched sample. (C) 2014 American Vacuum Society.
Simplified Interval Type-2 Fuzzy Neural Networks
(2014-05-01)
Lin, Yang-Yin
;
Liao, Shih-Hui
;
Chang, Jyh-Yeong
;
Lin, Chin-Teng
;
電控工程研究所
This paper describes a self-evolving interval type-2 fuzzy neural network (FNN) for various applications. As type-1 fuzzy systems cannot effectively handle uncertainties in information within the knowledge base, we propose a simple interval type-2 FNN, which uses interval type-2 fuzzy sets in the premise and the Takagi-Sugeno-Kang (TSK) type in the consequent of the fuzzy rule. The TSK-type consequent of fuzzy rule is a linear combination of exogenous input variables. Given an initially empty the rule-base, all rules are generated with on-line type-2 fuzzy clustering. Instead of the time-consuming K-M iterative procedure, the design factors q(l) and q(r) are learned to adaptively adjust the upper and lower positions on the left and right limit outputs, using the parameter update rule based on a gradient descent algorithm. Simulation results demonstrate that our approach yields fewer test errors and less computational complexity than other type-2 FNNs.
Dmail: A Globally Authenticated Email Service
(2014-05-01)
Cheng, Michael
;
Cho, Yi
;
Chen, Pokai
;
Shieh, Shiuhpyng Winston
;
交大名義發表
The global public-key authentication infrastructure standardized in the Domain Name System Security Extension (DNSSEC) paves the way for Dmail (DNSSEC-enabled email), a framework that allows secure email address authentication.
Efficiency Improvement of Blue LEDs Using a GaN Burried Air Void Photonic Crystal With High Air Filling Fraction
(2014-05-01)
Liu, Jia-Zhe
;
Charlton, Martin D. B.
;
Lin, Chung-Hsiang
;
Lee, Kang-Yuan
;
Krishnan, Chirenjeevi
In this paper, we investigate the efficiency enhancement of blue InGaN/GaN light-emitting diodes (LEDs) by incorporating a burried air void photonic crystal (BAVPC) layer within the epitaxial structure. As compared with the conventional patterned sapphire substrate (C-PSS) LEDs and flat sapphire substrate LEDs with BAVPC, the fabricated patterned sapphire substrate (PSS) LEDs with BAVPC exhibit the lowest full-width at half-maximum of (002) and (102) diffraction peaks, the highest light output power of 20.6 mW, and the highest external quantum efficiency of 37.4%. Remarkable performance improvement in the PSS LED with BAVPC is attributed to the better epitaxial quality with threading dislocations terminated by the BAVPC and the higher scattering at interface between GaN and air-void. By positioning the BAVPC directly below the multiple quantum wells (MQWs), it would cause the reduction in the number of trapped optical modes. The methodology optically isolates the MQWs from the underlying substrate and increases the optical output power. Moreover, threading dislocations are significantly suppressed using the BAVPC with high air filling fraction of similar to 50%. It is well proposed that this methodology provides a promising alternative to C-PSS LEDs.
具有雙晶銅線路層之電路板及其製作方法
(2014-05-01)
陳智
;
蕭翔耀
本發明係有關於一種具有雙晶銅線路層之電路板及其製作方法,其中電路板包括下列步驟:(A)提供一基板,其一表面設有一第一線路層,且第一線路層係包括一電性連接墊;(B)形成一第一介電層於基板之表面上;(C)形成複數開口於第一介電層中,其中每一開口係貫穿第一介電層並對應於電性連接墊以顯露電性連接墊;(D)於開口中形成一銅晶種層;(E)以一電鍍法於開口中沉積一奈米雙晶銅層;以及(F)退火處理基板以轉換銅晶種層成奈米雙晶銅,且奈米雙晶銅層及轉換後之銅晶種層係形成一第二線路層,而第二線路層包括複數形成於開口中之第一導電盲孔。
The Concentrations of Ambient Burkholderia Pseudomallei during Typhoon Season in Endemic Area of Melioidosis in Taiwan
(2014-05-01)
Chen, Ya-Lei
;
Yen, Yu-Chuan
;
Yang, Chun-Yuh
;
Lee, Min Sheng
;
Ho, Chi-Kung
Background: Melioidosis is a severe bacterial infection caused by Burkholderia pseudomallei with a high case-fatality rate. Epidemiological and animal studies show the possibility of inhalation transmission. However, no B. pseudomallei concentrations in ambient air have been researched. Here, we developed a method to quantify ambient B. pseudomallei and then measured concentrations of ambient B. pseudomallei during the typhoon season and the non-typhoon season to determine the factors influencing ambient B. pseudomallei levels. Methods: We quantified ambient B. pseudomallei by using a filter/real-time qPCR method in the Zoynan Region in Kaohsiung, southern Taiwan. Twenty-four hour samples were collected at a sampling rate of 20 L/min every day from June 11 to December 21, 2012 including during the typhoon season (June to September) and reference season (October to December). Results: We successfully developed a filtration/real-time qPCR method to quantify ambient B. pseudomallei. To our knowledge, this is the first report describing concentrations of ambient B. pseudomallei. Ambient B. pseudomallei were only detected during the typhoon season when compared to the reference season. For the typhoons affecting the Zoynan Region, the positive rates of ambient B. pseudomallei were very high at 80% to 100%. During June to December, rainfall was positively correlated with ambient B. pseudomallei with a statistical significance. Sediment at a nearby pond significantly influenced the concentration of ambient B. pseudomallei. During the typhoon month, the typhoon was positively correlated with ambient B. pseudomallei whereas wind speed was reversely correlated with ambient B. pseudomallei. Conclusions: Our data suggest the possibility of transmission of B. pseudomallei via inhalation during the typhoon season.
Slanted n-ZnO/p-GaN nanorod arrays light-emitting diodes grown by oblique-angle deposition
(2014-05-01)
Lee, Ya-Ju
;
Yang, Zu-Po
;
Lo, Fang-Yuh
;
Siao, Jhih-Jhong
;
Xie, Zhong-Han
High-efficient ZnO-based nanorod array light-emitting diodes (LEDs) were grown by an oblique-angle deposition scheme. Due to the shadowing effect, the inclined ZnO vapor-flow was selectively deposited on the tip surfaces of pre-fabricated p-GaN nanorod arrays, resulting in the formation of nanosized heterojunctions. The LED architecture composed of the slanted n-ZnO film on p-GaN nanorod arrays exhibits a well-behaving current rectification of junction diode with low turn-on voltage of 4.7 V, and stably emits bluish-white luminescence with dominant peak of 390 nm under the operation of forward injection currents. In general, as the device fabrication does not involve passivation of using a polymer or sophisticated material growth techniques, the revealed scheme might be readily applied on other kinds of nanoscale optoelectronic devices. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
多孔鈣鋁氧化物結構的製造方法
(2014-05-01)
陳三元
;
張博學
;
張彥博
;
陳俞君
本發明提供一種多孔鈣鋁氧化物結構的製造方法，包括：將多孔氧化鋁、含鈣溶液以及尿素溶液混合成混合溶液；對混合溶液進行第一加熱處理，於多孔氧化鋁的表面上形成含鈣氫氧化物；於第一加熱處理後，對混合溶液進行離心處理，使形成有含鈣氫氧化物的多孔氧化鋁轉變成多孔鈣鋁層狀水滑石結構；以及對多孔鈣鋁層狀水滑石結構進行第二加熱處理，使多孔鈣鋁層狀水滑石結構轉變成多孔鈣鋁氧化物結構。
Kinesthesia in a sustained-attention driving task
(2014-05-01)
Chuang, Chun-Hsiang
;
Ko, Li-Wei
;
Jung, Tzyy-Ping
;
Lin, Chin-Teng
;
生物科技學系
This study investigated the effects of kinesthetic stimuli on brain activities during a sustained-attention task in an immersive driving simulator. Tonic and phasic brain responses on multiple timescales were analyzed using time-frequency analysis of electroencephalographic (EEG) sources identified by independent component analysis (ICA). Sorting EEG spectra with respect to reaction times (RT) to randomly introduced lane-departure events revealed distinct effects of kinesthetic stimuli on the brain under different performance levels. Experimental results indicated that EEG spectral dynamics highly correlated with performance lapses when driving involved kinesthetic feedback. Furthermore, in the realistic environment involving both visual and kinesthetic feedback, a transitive relationship of power spectra between optimal-, suboptimal-, and poor-performance groups was found predominately across most of the independent components. In contrast to the static environment with visual input only, kinesthetic feedback reduced theta-power augmentation in the central and frontal components when preparing for action and error monitoring, while strengthening alpha suppression in the central component while steering the wheel. In terms of behavior, subjects tended to have a short response time to process unexpected events with the assistance of kinesthesia, yet only when their performance was optimal. Decrease in attentional demand, facilitated by kinesthetic feedback, eventually significantly increased the reaction time in the suboptimal-performance state. Neurophysiological evidence of mutual relationships between behavioral performance and neurocognition in complex task paradigms and experimental environments, presented in this study, might elucidate our understanding of distributed brain dynamics, supporting natural human cognition and complex coordinated, multi-joint naturalistic behavior, and lead to improved understanding of brain-behavior relations in operating environments. (C) 2014 Elsevier Inc. All rights reserved.
Effects of cathode materials on the characteristics of electrolyte supported micro-tubular solid oxide fuel cells
(2014-05-01)
Hsieh, Wen-Shuo
;
Lin, Pang
;
Wang, Sea-Fue
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effects of the GDC-LSCF (Ce0.8Gd0.2O0-delta-La0.6Sr0.4Co0.2Fe0.8O3-delta) cathode layer and the GDC interlayer on the electrochemical performance of the ScSZ (Zr0.8Sc0.2O2-delta) electrolyte supported (approximate to 270 mu m) micro-tubular SOFC cells are investigated in this study. Material formulation and sintering profile for fabricating the micro-tubular SOFC cells are developed to avoid physical defects caused by the large sintering shrinkage mismatch among the layers. Cell B (with the LSCF-GDC composite cathode layer and the GDC interlayer) reports an ohmic resistance slightly higher than that of Cell A (with the GDC -La0.8Sr0 2MnO3-delta., i.e. LSM, composite cathode), while its polarization resistance emerges to be significantly smaller than that of Cell A. In terms of cell performance, Cell B demonstrates an OCV value (>1.07 V) similar to that of Cell A and a maximum power density (0.26W cm(-2)) 44.4% greater than that of Cell A (0.17 W cm(-2)) at 850 degrees C. It can thus be concluded that using the LSCF-GDC composite-cathode layer and inserting the GDC interlayer help reduce the total cell impedance, thereby improving the power density of the tubular cells. (C) 2013 Elsevier B.V. All rights reserved.
清代番地治理與族群地權關係：以鳳山溪流域的竹塹社與客家佃戶為例
(2014-05)
李翹宏
;
Chiao-hung Lee
;
College of Hakka Studies
;
International Center for Hakka Studies
;
客家文化學院
本文首先透過重新理解相關歷史研究和文獻資料，釐析清帝國在臺番界的設定過程如何衍生各種番租地權，以及這些番租土地對地域社群的意義。其次藉著古文書資料分辨番租地的形成方式和歷史脈絡。以此為基礎，統計日治初期竹塹地區的土地申告書資料，分析鳳山溪流域（今新埔、關西，與部份竹北地區）的竹塹社平埔族人擁有的番租土地分布情形，以及同一個區域內客家佃戶的公共產業的分布。結論指出，番租地的重要意義在於它是地權關係的變動歷史過程的具現，這個歷史過程可分析為農業國家藉著番地地權的區劃，介入移墾漢人（多數為粵藉客家先民）與原住民番社之間基於不同生產模式的社會文化互動，而演變成帶有族群經濟特色的治理方式。從土地與社群關係的角度思考，番租地的形成和改變，以及公共產業的出現，可作為進一步探討藉著地權關係的歷史形構而建立的客家地域社會的基礎。
Monitoring Early First-Grade Reading Progress A Comparison of Two Measures
(2014-05-01)
Clemens, Nathan H.
;
Shapiro, Edward S.
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Wu, Jiun-Yu
;
Taylor, Aaron B.
;
Caskie, Grace L.
This study compared the validity of progress monitoring slope of nonsense word fluency (NWF) and word identification fluency (WIF) with early first-grade readers. Students (N = 80) considered to be at risk for reading difficulty were monitored with NWF and WIF on a 1-2 week basis across 11 weeks. Reading skills at the end of first grade were assessed using measures of passage reading fluency, real and pseudoword reading efficiency, and basic comprehension. Latent growth models indicated that although slope on both measures significantly predicted year-end reading skills, models including WIF accounted for more variance in spring reading skills than NWF, and WIF slope was more strongly associated with reading outcomes than NWF slope. Analyses of student growth plots suggested that WIF slope was more positively associated with later reading skills and discriminated more clearly between students according to successful or unsuccessful year-end reading outcomes. Although both measures may be used to monitor reading growth of at-risk students in early first grade, WIF may provide a clearer index of reading growth. Implications for data-based decision-making are discussed.
Total Synthesis of Quebrachamine through Macrolactamization
(2014-05-01)
Hsu, Shih-Wen
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Cheng, Hsiu-Yi
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Huang, An-Chi
;
Ho, Tse-Lok
;
Hou, Duen-Ren
The total synthesis of quebrachamine was achieved through the macrolactamization of cis-2-alkenylated indole 17, which was prepared by a Sonogashira reaction between indole 5b and piperidine 11 followed by cis-hydrogenation. We found that stoichiometric copper(I) iodide limited the undesired Glaser-type homocoupling of alkyne 11 that would otherwise take place during the Sonogashira coupling. This direct approach allowed the total synthesis in ten linear steps starting from commercially available chemicals. Conditions for the reduction of lactam 19 by lithium aluminiumhydride were adjustable, so that either (+/-)-quebrachamine or the analogue (+/-)-kopsiyunnanine D was prepared.
Optical assessment of the cardiac rhythm of contracting cardiomyocytes in vitro and a pulsating heart in vivo for pharmacological screening
(2014-05-01)
Lai, Yu-Cheng
;
Chang, Wei-Tien
;
Lin, Kuen-You
;
Liau, Ian
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應用化學系
Our quest in the pathogenesis and therapies targeting human heart diseases requires assessment of the contractile dynamics of cardiac models of varied complexity, such as isolated cardiomyocytes and the heart of a model animal. It is hence beneficial to have an integral means that can interrogate both cardiomyocytes in vitro and a heart in vivo. Herein we report an application of dual-beam optical reflectometry to determine noninvasively the rhythm of two representative cardiac models-chick embryonic cardiomyocytes and the heart of zebrafish. We probed self-beating cardiomyocytes and revealed the temporally varying contractile frequency with a short-time Fourier transform. Our unique dual-beam setup uniquely records the atrial and ventricular pulsations of zebrafish simultaneously. To minimize the cross talk between signals associated with atrial and ventricular chambers, we particularly modulated the two probe beams at distinct frequencies and extracted the signals specific to individual cardiac chambers with phase-sensitive detection. With this setup, we determined the atrio-ventricular interval, a parameter that is manifested by the electrical conduction from the atrium to the ventricle. To demonstrate pharmacological applications, we characterized zebrafish treated with various cardioactive and cardiotoxic drugs, and identified abnormal cardiac rhythms and atrioventricular (AV) blocks of varied degree. In light of its potential capability to assess cardiac models both in vitro and in vivo and to screen drugs with cardioactivity or toxicity, we expect this approach to have broad applications ranging from cardiopharmacology to developmental biology. (C) 2014 Optical Society of America
Zeta functions of complexes arising from PGL(3)
(2014-05-01)
Kang, Ming-Hsuan
;
Li, Wen-Ching Winnie
;
應用數學系
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Department of Applied Mathematics
In this paper we obtain a closed form expression of the zeta function Z(Xr,u) of a finite quotient Xr of the Bruhat-Tits building of PGL(3) over a nonarchimedean local field F by a discrete cocompact torsion-free subgroup Gamma of PGL3. Analogous to a graph zeta function, Z(Xr, u) is a rational function with two different expressions and it satisfies the Riemann hypothesis if and only if Xr is a Ramanujan complex. (C) 2014 Elsevier Inc. All rights reserved.
Hydrothermal Formation of Tungsten Trioxide Nanowire Networks on Seed-Free Substrates and Their Properties in Electrochromic Device
(2014-05-01)
Hung, Chung Jung
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Huang, Yi Hsuan
;
Chen, Chih Hao
;
Lin, Pang
;
Tseng, Tseung Yuen
Facile and cost-efficient hydrothermally grown 3-D tungsten trioxide (WO3) nanowires (NWs) network film on seed-free fluorine-doped tin oxide (FTO) substrates without using additive or capping agent is reported. The NW networks are hexagonal phase and the morphologies are changed by adjusting the pH of precursor solutions. Growth mechanism of WO3 NWs is also extensively discussed. The designed porous film exhibits remarkable enhancement of the electrochromic (EC) properties. In particular, a significant optical modulation (57% at 632 nm), fast color switching speed (bleaching: 7 s and coloration: 21 s), high coloration efficiency (120.3 cm(2) C-1 at 632 nm), high Li+ diffusion coefficient (2.14 x 10(-9) cm(2) s(-1)), and excellent cycling stability (87% after 1000 cycles) are achieved for the 3-D NWs film. The improved EC properties are mainly attributed to the highly porous film, which makes the Li+ diffusion becomes easier and provides larger specific surface area for charge-transfer reactions. Furthermore, we also reported an EC device (50 mm x 50 mm) with a simple two-electrode configuration showing high optical contrast. The 3-D WO3 NWs network film acts as an excellent EC material.
Low-temperature direct copper-to-copper bonding enabled by creep on highly (111)-oriented Cu surfaces
(2014-05-01)
Liu, Chien-Min
;
Lin, Han-Wen
;
Chu, Yi-Cheng
;
Chen, Chih
;
Lyu, Dian-Rong
We achieve low-temperature Cu-to-Cu direct bonding using highly (1 1 1)-orientated Cu films. The bonding temperature can be lowered to 200 degrees C at a stress of 114 psi for 30 min at 10(-3) torr. The temperature is lower than the reflow temperature of 250 degrees C for Pb-free solders. Our breakthrough is based on the finding that the Cu (1 1 1) surface diffusivity is the fastest among all the planes of Cu and the bonding process can occur through surface diffusion creep on the (1 1 1) surfaces. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Optimization of Cyclic-Delay Diversity Aided Frequency-Selective Scheduling in OFDMA Downlink Systems
(2014-05-01)
Chen, Yu-Fan
;
Sheen, Wern-Ho
;
Wang, Li-Chun
;
電機資訊學士班
;
電信工程研究所
Cyclic-delay diversity (CDD)-aided frequency-selective scheduling has been known as an effective technique for increasing the system capacity of orthogonal frequency-division multiple-access (OFDMA) systems. By increasing the channels\' frequency selectivity with different cyclic delays applied on transmit antennas, the merit of multiuser diversity can be more effectively exploited in the system. In this paper, we aim to optimize the design of the CDD-aided frequency-selective scheduling for OFDMA downlink systems. Optimization is done from two aspects: cyclic-delay search and scheduling-information feedback. In the optimization of cyclic-delay search, three new methods are proposed, including antenna-wise sequential search for frequency-nonselective (AWSS-FNS) channels, AWSS for frequency-selective (AWSS-FS) channels, and a genetic-algorithm-based search (GAS). AWSS-FNS achieves the optimal performance if a channel is frequency nonselective over a subchannel, whereas AWSS-FS and GAS provide good tradeoffs between system performance and complexity for channels that are frequency selective over a subchannel. In the optimization of scheduling-information feedback, a new channel-dependent feedback (CDF) method is proposed, where the feedback resource is allocated to users according to their frequency-selectivity rates and a principle of proportional fairness. The optimized scheduler is shown to provide significant improvement in both system sum rate and user fairness over previous methods under fixed feedback overhead.
Numerical modeling of interconnect flow channel design and thermal stress analysis of a planar anode-supported solid oxide fuel cell stack
(2014-05-01)
Wei, S. -S.
;
Wang, T. -H.
;
Wu, J. -S.
;
機械工程學系
;
Department of Mechanical Engineering
In this paper, we propose a new design of flow channel and stack arrangement based on the numerical study considering the effect of the flow channel design on the stack performance and analyze the thermal stress of a planar anode-supported solid oxide fuel cell stack. We also attempt to simplify the cell stack design without affecting its performance and propose an easier sealing method of cell stacks through the study of the thermal stress distribution. The results indicate that the new design, created by changing the cathode flow channel to a porous current collector, with a 6.3% increase in power density. an 8.6% increase in electrical efficiency. Both more uniform flow and current density distribution can be obtained as compared with a conventional counter-flow design. In addition, we propose a new design direction of cell stack, which could be simpler and easier to fabricate, in which material can easily undertake the resulting stress based on the thermal stress analysis. (C) 2014 Elsevier Ltd. All rights reserved.
Feature issue introduction: optical materials for flat panel displays
(2014-05-01)
Lee, Wei
;
Park, Jongwook
;
Subramanian, Vivek
;
Takezoe, Hideo
;
光電學院
This feature issue on "Optical Materials for Flat Panel Displays" of Optical Materials Express spotlights recent advances in optical materials for information display applications. It comprises 12 papers primarily on liquid-crystal and light-emitting materials and their devices. It is hoped that the present special theme issue encourages and stimulates further research endeavors into novel optical materials with improved optical or electro-optical properties, their mechanisms of operation, and their promoted device performance for potential flat-panel-display applications. (C) 2014 Optical Society of America