Browsing by Issue Date, starting with "2014-10-13"

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Characteristics of electrolyte supported micro-tubular solid oxide fuel cells with GDC-ScSZ bilayer electrolyte
(2014-10-13)
Hsieh, Wen-Shuo
;
Lin, Pang
;
Wang, Sea-Fue
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In this study, a gadolinia-doped ceria (GDq-supported micro tubular SOFC (T-SOFC) was fabricated using extrusion and dip-coating techniques (Cell A). The effects of inserting a scandium-stabilized zirconia (ScSZ) layer as an electron blocking layer between the GDC layer and the GDC-Ni anode layer were also explored (Cell B). The microstructures and electrochemical performances of Cell A and Cell B were investigated and compared. The layer thicknesses of the GDC and ScSZ bi-layer electrolytes were approximately 285 mu m and 8 mu m respectively. With the inserted ScSZ layer, both the ohmic resistance and the polarization resistance significantly increased at all the operating temperatures. The increase in the ohmic resistance of Cell B was predominantly due to the interfacial resistance, while the substantial escalation in the polarization resistance was mainly because of the low bulk oxygen diffusion process in the ScSZ layer and the smaller charge transfer processes occurring at the interfaces. The OCV of Cell B showed a slight decrease from 1.06 to 0.98 V and that of Cell A experienced an obvious decline from 0.92 to 0.76 V as the temperature rose from 650 to 800 degrees C. The ScSZ layer of Cell B successfully inhibited the OCV loss caused by the electronic conduction in GDC. The maximum power densities (MPDs) of Cell A at 650, 700, 750, and 800 degrees C were 0.20, 0.27, 0.33, and 0.36 Wcm(-2), and those of Cell B 0.16, 0.23, 0.32, and 0.42 Wcm(-2). The MPD of Cell B was improved at temperatures above 750 degrees C but remained inferior to that of Cell A below 750 degrees C. This is due to the fact that, as operating temperature increased above 750 degrees C, the benefit of the higher OCV in Cell B surpassed the deficiency of the higher cell resistance, thereby leading to a higher MPD. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Developing an EEG-based on-line closed-loop lapse detection and mitigation system
(2014-10-13)
Wang, Yu-Te
;
Huang, Kuan-Chih
;
Wei, Chun-Shu
;
Huang, Teng-Yi
;
Ke, Li-Wei
In America, 60% of adults reported that they have driven a motor vehicle while feeling drowsy, and at least 15-20% of fatal car accidents are fatigue-related. This study translates previous laboratory-oriented neurophysiological research to design, develop, and test an On-line Closed-loop Lapse Detection and Mitigation (OCLDM) System featuring a mobile wireless dry-sensor EEG headgear and a cell-phone based real-time EEG processing platform. Eleven subjects participated in an event-related lane-keeping task, in which they were instructed to manipulate a randomly deviated, fixed-speed cruising car on a 4-lane highway. This was simulated in a 1st person view with an 8-screen and 8-projector immersive virtual-reality environment. When the subjects experienced lapses or failed to respond to events during the experiment, auditory warning was delivered to rectify the performance decrements. However, the arousing auditory signals were not always effective. The EEG spectra exhibited statistically significant differences between effective and ineffective arousing signals, suggesting that EEG spectra could be used as a countermeasure of the efficacy of arousing signals. In this on-line pilot study, the proposed OCLDM System was able to continuously detect EEG signatures of fatigue, deliver arousing warning to subjects suffering momentary cognitive lapses, and assess the efficacy of the warning in near real-time to rectify cognitive lapses. The on-line testing results of the OCLDM System validated the efficacy of the arousing signals in improving subjects\' response times to the subsequent lane-departure events. This study may lead to a practical on-line lapse detection and mitigation system in real-world environments.
Development of an Anti-Methoxy Poly(ethylene glycol) (alpha-mPEG) Cell-Based Capture System to Measure mPEG and mPEGylated Molecules
(2014-10-14)
Chuang, Kuo-Hsiang
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Kao, Chien-Han
;
Roffler, Steve R.
;
Lu, Ssu-Jung
;
Cheng, Ta-Chun
Quantitative pharmacokinetic analysis of methoxy-poly(ethylene glycol) (mPEG) and mPEGylated molecules is important for clinical drug development. Here we developed sensitive sandwich and competitive ELISAs by expressing an anti-mPEG antibody on the surface of fibroblasts for effective capture of mPEG molecules in biological samples. alpha-mPEG sandwich ELISA could quantify the higher-molecular-weight of mPEG (2, 5, and 20 kDa) and mPEGylated molecules. alpha-mPEG cell-based competitive ELISA was developed to measure the lower-molecular-weight of mPEG molecules (559, 750, and 1000 Da) at nanomolar levels. In addition, alpha-mPEG cell-based ELISA was unaffected by the presence of 10% human serum or murine serum. We further demonstrate that the alpha-mPEG cell-based ELISA determined similar pharmacokinetics of mPEG(5K) as traditional gamma counting of I-131-mPEG(5K). The alpha-mPEG cell-based ELISA may provide an accurate, high sensitivity and easy-to-use tool for directly measuring mPEG and mPEGylated molecules in complex biological samples to accelerate the clinical development of mPEG drugs.
High efficiency buck-boost power converter
(2014-10-14)
Chen Ke-Horng
;
Wu Wei-Quan
;
Ho Hsin-Hsin
A buck-boost power converter switches the switches thereof with a novel sequence and extends the switching periods of the switches to reduce the switching loss and conduction loss when the input voltage thereof approaches the output voltage thereof. The influence of the load current of the power converter on the duty thereof is taken into account to switch the power converter between modes at correct time points, so as to prevent the output voltage from being affected by the mode switching.
Phase-locked loop with loop gain calibration, gain measurement method, gain calibration method and jitter measurement method for phase-locked loop
(2014-10-14)
Chen Wei-Zen
;
Chuang Shu-Chin
The invention provides a phase-locked loop with loop gain calibration and methods for measuring an oscillator gain, gain calibration and jitter measurement for a phase-locked loop. The method for measuring an oscillator gain of a phase-locked loop includes the steps of providing a varying code at an input end of the oscillator; outputting excess reference phase information by a reference phase integral path and outputting excess feedback phase information based on the varying code by a feedback phase integral path; and obtaining an estimated gain information of the oscillator based on the excess reference phase information and the excess feedback phase information.
Estimation and Suppression of Dispersion-Induced Phase Noise in W-band Direct-Detection OFDM Radio-Over-Fiber Systems
(2014-10-15)
Wei, Chia-Chien
;
Lin, Chun-Ting
;
Huang, Hou-Tzu
;
Liang, Wan-Ling
;
Chi, Sien
This study experimentally investigated the impact of dispersion-induced phase noise (DPN) on the transmission performance of a 100-GHz DD OFDM-RoF system. We sought to extend the transmission distance through the reduction of DPN using two digital phase noise suppression (PNS) schemes, based on the assumption that all subcarriers suffer from common DPN. The decision-aided PNS (DA-PNS) scheme treats the OFDM signal as feedback to aid in the calculation of DPN without incurring additional overhead. Pilot-aided PNS (PA-PNS) estimates the common DPN by inserting an additional optical pilot tone with guard band. Although both schemes are able to extend fiber transmission distance to beyond 150 km, the PA-PNS scheme tends to be outperformed by the DA-PNS scheme due to additional power required for the pilot tone. Nonetheless, in the DA-PNS scheme, the bandwidth of the estimated DPN must be truncated to avoid error propagation, which can result in the relatively faster increment in the transmission penalty. In contrast, the PA-PNS scheme maintains the variation in penalty to <1 dB, thereby achieving the performance that is insensitive to transmission distance.
Power partial isometry index and ascent of a finite matrix
(2014-10-15)
Gau, Hwa-Long
;
Wu, Pei Yuan
;
交大名義發表
;
應用數學系
;
National Chiao Tung University
We give a complete characterization of nonnegative integers j and k and a positive integer n for which there is an n-by-n matrix with its power partial isometry index equal to j and its ascent equal to k. Recall that the power partial isometry index p(A) of a matrix A is the supremum, possibly infinity, of nonnegative integers j such that I, A, A(2), . . . , A(j) are all partial isometries while the ascent a(A) of A is the smallest integer k >= 0 for which ker A(k) equals ker A(k)+1. It was known before that, for any matrix A, either p(A) <= min{a(A), n - 1} or p(A) = infinity. In this paper, we prove more precisely that there is an n-by-n matrix A such that p(A) = j and a(A) = k if and only if one of the following conditions holds: (a) j = k <= n - 1, (b) j <= k - 1 and j+k <= n - 1, or (c) j <= k - 2 and j+ k = n. This answers a question we asked in a previous paper. (C) 2014 Elsevier Inc. All rights reserved.
Simple 2 x 2 MIMO 60-GHz Optical/Wireless System With Extending Fiber Transmission Distance
(2014-10-15)
Huang, Hou-Tzu
;
Lin, Chun-Ting
;
Chiang, Ya-Tang
;
Wei, Chia-Chien
;
Ho, Chun-Hung
This paper presents a simple 2 x 2 multiple-input multiple-output (MIMO) 60-GHz radio-over-fiber system. Due to the proposed specific frequency arrangement of driving signals, each optical transmitter requires only a single-drive Mach-Zehnder modulator with 3-dB bandwidth of less than 35 GHz. This arrangement of frequencies can increase the tolerance of optical signals to dispersion-induced RF fading, thereby extending fiber transmission distance. Unfortunately, this scheme leads to signal-to-signal beating interference (SSBI), which can deteriorate system performance. Thus, we employed a 2 x 2 MIMO scheme to enhance data capacity by combining two data streams and two corresponding SSBIs prior to signal demodulation. We also developed a novel iterative equalization technique to mitigate SSBI in the MIMO system. The proposed system achieved a maximum capacity of 55.9-Gb/s in the transmission of 7-GHz orthogonal frequency division multiplexing signals over 12-km fiber and 3.5-m air transmission using a bit-loading algorithm.
Ab initio chemical kinetics for the N2H4 + NOx (x=1-3) reactions and related reverse processes
(2014-10-15)
Raghunath, P.
;
Lin, Y. H.
;
Lin, M. C.
;
交大名義發表
;
應用化學系
The kinetics and mechanisms for N2H4 + NOx, (x = 1-3) reactions and the related reverse reactions have been investigated by ab initio molecular orbital theory based on the CCSD(T)/CBS/ICCSD/6-31G(d,p), CCSD(T)//B3LYP and CCSD(T)//BH&HLYP methods with the 6-311++G(3df,2p) basis set. These reactions are important to the propulsion chemistry of the N2H4-N2O4 propellant system. The results show that the reactions of N2H4 with NO and NO2 producing N2H3 + HNO and N2H3 + c-HONO by H-abstraction with 33.7 and 10.3 kcal/mol barriers, respectively, are dominant. For the N2H4 + NO3(D-3h) reaction via two pre-reaction van der Waals complexes with 0.5 kcal/mol and -1.6 kcal/mol binding energies produces HNO3 + N2H3 by H-abstraction and t-HONO + N2H3O by concerted O- and H-atom transfers, respectively. The predicted enthalpies of formation of various products at 0 K are in good agreement with available experimental data within reported errors. Furthermore, the rate constants for the forward and some key reverse reactions have been predicted in the temperature range 300-2000 K with tunneling corrections using transition state theory (for direct abstraction) and variational Rice-Ramsperger-Kassel-Marcus theory (for association! decomposition) by solving the master equation. (C) 2014 Elsevier B.V. All rights reserved.
Accurate gradient approximation for complex interface problems in 3D by an improved coupling interface method
(2014-10-15)
Shu, Yu-Chen
;
Chern, I-Liang
;
Chang, Chien C.
;
應用數學系
;
Department of Applied Mathematics
Most elliptic interface solvers become complicated for complex interface problems at those "exceptional points" where there are not enough neighboring interior points for high order interpolation. Such complication increases especially in three dimensions. Usually, the solvers are thus reduced to low order accuracy. In this paper, we classify these exceptional points and propose two recipes to maintain order of accuracy there, aiming at improving the previous coupling interface method [26]. Yet the idea is also applicable to other interface solvers. The main idea is to have at least first order approximations for second order derivatives at those exceptional points. Recipe 1 is to use the finite difference approximation for the second order derivatives at a nearby interior grid point, whenever this is possible. Recipe 2 is to flip domain signatures and introduce a ghost state so that a second-order method can be applied. This ghost state is a smooth extension of the solution at the exceptional point from the other side of the interface. The original state is recovered by a post-processing using nearby states and jump conditions. The choice of recipes is determined by a classification scheme of the exceptional points. The method renders the solution and its gradient uniformly second-order accurate in the entire computed domain. Numerical examples are provided to illustrate the second order accuracy of the presently proposed method in approximating the gradients of the original states for some complex interfaces which we had tested previous in two and three dimensions, and a real molecule (1D63) which is double-helix shape and composed of hundreds of atoms. (C) 2014 Elsevier Inc. All rights reserved.
Femtosecond laser-induced nanoperiodic structures and simultaneous crystallization in amorphous indium-tin-oxide thin films
(2014-10-15)
Cheng, C. W.
;
Lee, I. M.
;
Chen, J. S.
;
機械工程學系
;
Department of Mechanical Engineering
Fabrication of crystalline indium-tin-oxide (c-ITO) nanogratings and smooth line patterns on amorphous ITO (a-ITO) thin films by femtosecond laser-induced structuring and simultaneous crystallization followed by chemical etching is demonstrated. Three types of c-ITO structures are obtained merely by controlling the laser pulse energy of a high-repetition rate femtosecond laser at wavelength 532 nm: nanogratings perpendicular to laser polarization direction with period of 130 perpendicular to 11 nm, smooth c-ITO line patterns as well as nanogratings parallel to laser polarization direction with period of 390 +/- 10 nm. Large area c-ITO patterns and nanograting structures are fabricated, which are expected to be used in optoelectronic and micro-electronic devices. (C) 2014 Elsevier B.V. All rights reserved.
Optical Nyquist filters based on silicon coupled resonator optical waveguides
(2014-10-15)
Xu, Ke
;
Sung, Jiun-Yu
;
Wong, Chi Yan
;
Cheng, Zhenzhou
;
Chow, Chi Wai
We propose an integrated optical Nyquist filter based on silicon coupled resonator optical waveguides (CROW). The designed filter can shape the 28 Gbaud QPSK spectrum to a spectrum having 0.2 roll-off raised cosine shape with G-dB bandwidth equals to the baud rate. The impact of the fabrication tolerance induced coupling coefficients error on the figure of merits of the filter is considered. The filter overall performance is investigated in a Nyquist-WDM system and compared with a 4th order super Gaussian filter. (C) 2014 Elsevier B.V. All rights reserved.
Theoretical and Experimental Investigation of a 2 x 2 MIMO OFDM Radio-Over-Fiber System at 60-GHz With I/Q Imbalance Compensation
(2014-10-15)
Ho, Chun-Hung
;
Lin, Chun-Ting
;
Lu, Tsung-Hung
;
Huang, Hou-Tzu
;
Shih, Boris (Po-Tsung)
This paper investigates the efficacy of two methods for compensating I/Q imbalance, which causes serious performance problems in wideband (6.98-GHz spectrum) millimeter-wave systems employing MIMO signal transmission. A 60-GHz orthogonal frequency division multiplexing (OFDM) RoF system employing 2 x 2 MIMO technology is implemented using a commonly used training symbol arrangement and a proposed method. We experimentally demonstrate that the proposed training symbol arrangement performed significantly better than the commonly used approach. By combining the proposed training symbol arrangement with LMS I/Q compensation and bit-loading, we achieve an extremely high wireless data rate transmission of 75.211 Gb/s over both 50 km of standard single-mode fiber and 3.5-m wireless distance. The optical power penalty after 50-km fiber transmission was only similar to 1 dB.
Accurate gradient approximation for complex interface problems in 3D by an improved coupling interface method
(2014-10-15)
Shu, Yu-Chen
;
Chern, I-Liang
;
Chang, Chien C.
;
應用數學系
;
Department of Applied Mathematics
Most elliptic interface solvers become complicated for complex interface problems at those "exceptional points" where there are not enough neighboring interior points for high order interpolation. Such complication increases especially in three dimensions. Usually, the solvers are thus reduced to low order accuracy. In this paper, we classify these exceptional points and propose two recipes to maintain order of accuracy there, aiming at improving the previous coupling interface method [26]. Yet the idea is also applicable to other interface solvers. The main idea is to have at least first order approximations for second order derivatives at those exceptional points. Recipe 1 is to use the finite difference approximation for the second order derivatives at a nearby interior grid point, whenever this is possible. Recipe 2 is to flip domain signatures and introduce a ghost state so that a second-order method can be applied. This ghost state is a smooth extension of the solution at the exceptional point from the other side of the interface. The original state is recovered by a post-processing using nearby states and jump conditions. The choice of recipes is determined by a classification scheme of the exceptional points. The method renders the solution and its gradient uniformly second-order accurate in the entire computed domain. Numerical examples are provided to illustrate the second order accuracy of the presently proposed method in approximating the gradients of the original states for some complex interfaces which we had tested previous in two and three dimensions, and a real molecule (1D63) which is double-helix shape and composed of hundreds of atoms. (C) 2014 Elsevier Inc. All rights reserved.
On a piecewise-smooth map arising in ecology
(2014-10-15)
Huang, Chun-Ming
;
Juang, Jong
;
應用數學系
;
數學建模與科學計算所(含中心)
;
Department of Applied Mathematics
In this paper, we study a two-dimensional piecewise smooth map arising in ecology. Such map, containing two parameters d and beta, is derived from a model describing how masting of a mature forest happens and synchronizes. Here d is the energy depletion quantity and beta is the coupling strength. Our main results are the following. First, we obtain a "weak" Sharkovskii ordering for the map on its nondiagonal invariant region for a certain set of parameters. In particular, we show that its Sharkovskii ordering is the natural number (resp., the positive even number) for beta > 1 (resp., 0 < beta < 1). Second, we obtain a region of parameter space for which its corresponding global dynamics can be completely characterized. (C) 2014 Elsevier Inc. All rights reserved.
Silicon nanowire field-effect-transistor based biosensors: From sensitive to ultra-sensitive
(2014-10-15)
Shen, Mo-Yuan
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Li, Bor-Ran
;
Li, Yaw-Kuen
;
應用化學系
;
Department of Applied Chemistry
Silicon nanowire field effect transistors (SiNW-FETs) have shown great promise as biosensors in highly sensitive, selective, real-time and label-free measurements. While applications of SiNW-FETs for detection of biological species have been described in several publications, less attention has been devoted to summarize the conjugating methods involved in linking organic bio-receptors with the inorganic transducer and the strategies of improving the sensitivity of devices. This article attempts to focus on summarizing the various organic immobilization approaches and discussing various sensitivity improving strategies, that include (I) reducing non-specific binding, (II) alignment of the probes, (III) enhancing signals by charge reporter, (IV) novel architecture structures, and (V) sensing in the subthreshold regime. (C) 2014 Elsevier B.V. All rights reserved.
Grain growth in electroplated (111)-oriented nanotwinned Cu
(2014-10-15)
Huang, Yi-Sa
;
Liu, Chien-Min
;
Chiu, Wei-Lan
;
Chen, Chih
;
材料科學與工程學系
The grain growth of pulse-plated (111)-oriented nanotwinned Cu (nt-Cu) was investigated at 200-350 degrees C. The results indicate that after the annealing, the nt-Cu exhibits good thermal stability, and columnar grains with a (111)-oriented nt-Cu structure are maintained up to 300 degrees C. The columnar grains consume the original fine-grained region at the bottom of the sample. In addition, these fine grains were converted into nanotwinned columnar grains with a (111) orientation. The electroplated Cu film possessed extremely high (111) preferred orientation after the annealing. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Vibrational effects on UV/Vis laser-driven pi-electron ring currents in aromatic ring molecules
(2014-10-17)
Mineo, H.
;
Lin, S. H.
;
Fujimura, Y.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
We present the results of a theoretical study of vibrational effects on UV/Vis laser-driven p-electron ring currents in aromatic ring molecules. We consider vibrational effects on both coherent and non-coherent (single quantum state) ring currents. The coherent ring current originates from an excitation of a pair of quasi-degenerate electronic states by an ultrashort linearly polarized UV/Vis laser pulse, while the non-coherent ring current originates from by an excitation of a degenerated electronic state of an aromatic ring molecule with high symmetry by a circularly polarized electric field of a UV/Vis laser pulse. The magnitude of a generated ring current can be expressed as an average of those of the bond currents for both the coherent and non-coherent cases. We derive an analytical expression for the magnitude of the bond currents in the adiabatic approximation. Using the expression, we performed calculations of a non-coherent ring current generated in the optically allowed excited state (E-1(1U)) of benzene and the time evolution of coherent ring current of (P)-2,2-biphenol. Vibrational effects on the non-coherent ring current of benzene were found to be negligibly small. We paid particular attention to the vibrational effects induced by the torsion mode on time evolution of the coherent ring current along the bond bridging between the two aromatic rings of (P)-2,2-biphenol. By comparing the time evolution of the coherent ring current with that in the frozen-nuclear approximation, we found that inclusion of the low-frequency torsion mode brings about modulations in the beating in the ring current. The modulations in the time evolution of the coherent ring current were brought about by contribution of several pairs of the coherently excited vibronic states. Coherent vibronic ring currents generated from pairs of the coherently excited vibronic states interfere each other. The existence of the pairs originates from relatively large potential displacement of the torsion mode between the two excited states for (P)-2,2-biphenol. Temperature effects on the time-dependent coherent ring current were also investigated. (C) 2014 Elsevier B.V. All rights reserved.
實踐知識力　自造全新世代
(2014-10-19)
洪雯倩
;
劉敏慈
;
Department of Communication and Technology
;
傳播與科技學系
不只學習知識，更要利用知識。台灣科學館與【自造世代】製作團隊將maker的成功秘訣告訴你。
情牽三十年　不變的羈絆
(2014-10-19)
劉雨婕
;
Department of Communication and Technology
;
傳播與科技學系
《最好的妳》描寫一對情同姊妹的好朋友，兩人情誼維繫三十年之久，一句「我需要妳」，她們便能形影不離。