Browsing by Issue Date, starting with "2015-09-29"

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Instabilities of Layers of Deposited Molecules on Chemically Stripe Patterned Substrates: Ridges versus Drops
(2015-09-29)
Honisch, Christoph
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Lin, Te-Sheng
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Heuer, Andreas
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Thiele, Uwe
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Gurevich, Svetlana V.
A mesoscopic continuum model is employed to analyze the transport mechanisms and structure formation during the redistribution stage of deposition experiments where organic molecules are deposited on a solid substrate with periodic stripe-like wettability patterns. Transversally invariant ridges located on the more wettable stripes are identified as very important transient states and their linear stability is analyzed accompanied by direct numerical simulations of the fully nonlinear evolution equation for two-dimensional substrates. It is found that there exist two different instability modes that lead to different nonlinear evolutions that result (i) at large ridge volume in the formation of bulges that spill from the more wettable stripes onto the less wettable bare substrate and (ii) at small ridge volume in the formation of small droplets located on the more wettable stripes. In addition, the influence of different transport mechanisms during redistribution is investigated focusing on the cases of convective transport with no-slip at the substrate, transport via diffusion in the film bulk and via diffusion at the film surface. In particular, it is shown that the transport process does neither influence the linear stability thresholds nor the sequence of morphologies observed in the time simulation, but only the ratio of the time scales of the different process phases.
Microchannel Wetting for Controllable Patterning and Alignment of Silver Nanowire with High Resolution
(2015-09-30)
Yang, Bo-Ru
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Cao, Wu
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Liu, Gui-Shi
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Chen, Hui-Jiuan
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Noh, Yong-Young
Patterning and alignment of conductive nanowires are essential for good electrical isolation and high conductivity in various applications. Herein a facile bottom-up, additive technique is developed to pattern and align silver nanowires (AgNWs) by manipulating wetting of dispersions in microchannels. By forming hydrophobic/hydrophilic micropatterns down to 8 mu m with fiuoropolymer (Cytop) and SiO2, the aqueous AgNW dispersions with the optimized surface tension and viscosity self-assemble into microdroplets and then dry to form anisotropic AgNW networks. The alignment degree characterized by the full width at half-maximum (FWHM) can be well-controlled from 39.8 degrees to 84.1 degrees by changing the width of microchannels. A mechanism is proposed and validated by statistical analysis on AgNW alignment, and a static model is proposed to guide the patterning of general NWs. The alignment reduced well the electrical resistivity of AgNW networks by a factor of 5 because of the formation of efficient percolation path for carrier conduction.
Tailor: a computational framework for detecting non-templated tailing of small silencing RNAs
(2015-09-30)
Chou, Min-Te
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Han, Bo W.
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Hsiao, Chiung-Po
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Zamore, Phillip D.
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Weng, Zhiping
Small silencing RNAs, including microRNAs, endogenous small interfering RNAs (endo-siRNAs) and Piwi-interacting RNAs (piRNAs), have been shown to play important roles in fine-tuning gene expression, defending virus and controlling transposons. Loss of small silencing RNAs or components in their pathways often leads to severe developmental defects, including lethality and sterility. Recently, non-templated addition of nucleotides to the 3' end, namely tailing, was found to associate with the processing and stability of small silencing RNAs. Next Generation Sequencing has made it possible to detect such modifications at nucleotide resolution in an unprecedented throughput. Unfortunately, detecting such events from millions of short reads confounded by sequencing errors and RNA editing is still a tricky problem. Here, we developed a computational framework, Tailor, driven by an efficient and accurate aligner specifically designed for capturing the tailing events directly from the alignments without extensive post-processing. The performance of Tailor was fully tested and compared favorably with other general-purpose aligners using both simulated and real datasets for tailing analysis. Moreover, to show the broad utility of Tailor, we used Tailor to reanalyze published datasets and revealed novel findings worth further experimental validation. The source code and the executable binaries are freely available at https://github.com/jhhung/Tailor.
Design and quasi-static characteristics study on a planar piezoelectric nanopositioner with ultralow parasitic rotation
(2015-10-01)
Lin, Hung-Ruei
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Cheng, Chiao-Hua
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Hung, Shao-Kang
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機械工程學系
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Department of Mechanical Engineering
This paper presents a particular mechanism design which is inherently inclined to have no parasitic rotation. The flexure-based stage comprises symmetric flexure guiding mechanism and two piezoelectric stack actuators. The layout of the stage is evaluated by finite element analysis, and the results indicate that the proposed design exhibits ultralow parasitic rotation. A prototype of the stage is then fabricated, and its performance is tested. Experimental results show that the stage has a stroke of 500 mu m x 500 mu m and the crosstalk is less than 1%. The maximum parasitic rotation is +/- 1.2 arcsec at a stroke of 500 mu m. (C) 2015 Elsevier Ltd. All rights reserved.
Exploring corporate citizenship and purchase intention: mediating effects of brand trust and corporate identification
(2015-10-01)
Tsai, Yuan Hui
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Joe, Sheng-Wuu
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Lin, Chieh-Peng
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Chiu, Chou-Kang
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Shen, Kuei-Tzu
Corporate citizenship represents various organizational activities and status related to the organization\'s societal and stakeholder obligations. This study develops five different dimensions of corporate citizenship and examines the relationship between the five dimensions and purchase intention by including two key mediators. In the proposed model of this study, purchase intention is indirectly affected by economic, legal, ethical, general philanthropic, and strategic philanthropic citizenship via the mediation of corporate identification and brand trust. Empirical testing using a survey of 353 consumers from various industries confirms most of our hypothesized effects. Last, managerial implications for corporate leaders and limitations of our findings are discussed in depth.
Approach to analytically minimize the LCD moire by image-based particle swarm optimization
(2015-10-01)
Tsai, Yu-Lin
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Tien, Chung-Hao
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光電工程學系
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Department of Photonics
In this paper, we proposed a methodology to optimize the parametric window of a liquid crystal display (LCD) system, whose visual performance was deteriorated by the pixel moire arising in between multiple periodic structures. Conventional analysis and minimization of moire patterns are limited by few parameters. With the proposed image-based particle swarm optimization (PSO), we enable a multivariable optimization at the same time. A series of experiments was conducted to validate the methodology. Due to its versatility, the proposed technique will certainly have a promising impact on the fast optimization in LCD design with more complex configuration. (C) 2015 Optical Society of America
Forecasting the purchase intention of IT product: Key roles of trust and environmental consciousness for IT firms
(2015-10-01)
Lin, Chieh-Peng
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Tsai, Yuan-Hui
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Chiu, Chou-Kang
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Liu, Chia-Ping
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經營管理研究所
The dramatic deviations between a firm\'s CSR statements and its actual business practices show negative effects on consumers\' trust and purchase intention. This study assesses consumers\' purchase intention of IT product from the aspect of trust and environmental consciousness. The empirical results of this study show that the positive relationship between trust and purchase intention is positively moderated by environmental consciousness. Materialism increases the positive interaction effect of trust and environmental consciousness on purchase intention, such that the positive relationship between trust and purchase intention is stronger when both environmental consciousness and materialism are higher. Materialism increases the negative interaction effect of hypocrisy and environmental consciousness on trust, such that the negative relationship between hypocrisy and trust is stronger when both environmental consciousness and materialism are higher. (C) 2015 Elsevier Inc All rights reserved.
Pole-Like Road Object Detection From Mobile Lidar System Using a Coarse-to-Fine Approach
(2015-10-01)
Teo, Tee-Ann
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Chiu, Chi-Min
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土木工程學系
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Department of Civil Engineering
The requirements of three-dimensional (3-D) road objects have increased for various applications, such as geographic information systems and intelligent transportation systems. The use of mobile lidar systems (MLSs) running along road corridors is an effective way to collect accurate road inventories, but MLS feature extraction is challenged by the blind scanning characteristics of lidar systems and the huge amount of data involved; therefore, an automatic process for MLS data is required to improve efficiency of feature extraction. This study developed a coarse-to-fine approach for the extraction of pole-like road objects from MLS data. The major work consists of data preprocessing, coarse-to-fine segmentation, and detection. In data preprocessing, points from different trajectories were reorganized into road parts, and building facades alongside road corridors were removed to reduce their influence. Then, a coarse-to-fine computational framework for the detection of pole-like objects that segments point clouds was proposed. The results show that the pole-like object detection rate for the proposed method was about 90%, and the proposed coarse-to-fine framework was more efficient than the single-scale framework. These results indicate that the proposed method can be used to effectively extract pole-like road objects from MLS data.
LIMIT BEHAVIOR OF MAXIMA IN GEOMETRIC WORDS REPRESENTING SET PARTITIONS
(2015-10-01)
Fuchs, Michael
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Javanian, Mehri
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應用數學系
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Department of Applied Mathematics
We consider geometric words omega(1) ... omega(n) with letters satisfying the restricted growth property omega(k) <= d max{omega(0), ..., omega(k-1)}, where omega(0) := 0 and d >= 1. For d = 1 these words are in 1-to-1 correspondence with set partitions and for this case, we show that the number of left-to-right maxima (suitable centered) does not converge to a fixed limit law as n tends to infinity. This becomes wrong for d >= 2, for which we prove that convergence does occur and the limit law is normal. Moreover, we also consider related quantities such as the value of the maximal letter and the number of maximal letters and show again non-convergence to a fixed limit law.
Observation of an Excitonic Quantum Coherence in CdSe Nanocrystals
(2015-10-01)
Dong, Shuo
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Trivedi, Dhara
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Chakrabortty, Sabyasachi
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Kobayashi, Takayoshi
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Chan, Yinthai
Recent observations of excitonic coherences within photosynthetic complexes suggest that quantum coherences could enhance biological light harvesting efficiencies. Here, we employ optical pump-probe spectroscopy with few-femtosecond pulses to observe an excitonic quantum coherence in CdSe nanocrystals, a prototypical artificial light harvesting system. This coherence, which encodes the high-speed migration of charge over nanometer length scales, is also found to markedly alter the displacement amplitudes of phonons, signaling dynamics in the non-Born-Oppenheimer regime.
Effects of commercial video games on cognitive elaboration of physical concepts
(2015-10-01)
Sun, Chuen-Tsai
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Ye, Shu-Hao
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Wang, Yu-Ju
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資訊工程學系
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Department of Computer Science
The authors use physical concepts to investigate cognitive elaboration using a commercial game-based review teaching method versus a lecture-based method. Experiments involved two popular casual games: Cut the Rope (pendulum concept) and Angry Bird Space (circular motion), with concept maps and multiple-choice tests used as assessment tools. Our goal was to analyze concept reinforcement and reorganization via commercial games for a group of junior high school students. A total of 83 students (15-16 years old), were randomly assigned to an experimental group (review using commercial casual games) or a control group (lecture-based review). Our results suggest that (a) the games supported the elaboration potential of learned physical concepts as measured by concept maps, and (b) concept maps are more suitable than multiple-choice tests for estimating the effects of commercial games on cognitive elaboration. Three key design features of commercial games that can support cognitive elaboration of physical concepts are discussed. (C) 2015 Elsevier Ltd. All rights reserved.
Hedonic and utilitarian shopping values in airport shopping behavior
(2015-10-01)
Chung, Yi-Shih
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This study aims to examine airport travelers\' shopping decision mechanisms based on a value-attitude-behavior framework. In particular, the proposed model investigates the complex relationships between pairs of shopping values (hedonic versus utilitarian), attitudes (cognitive versus affective), and behavior (repatronage intention versus retailer interest) to compare the relative importance between hedonicand utilitarian-oriented decision paths. A survey was administered at Taiwan Taoyuan International Airport, where 300 valid questionnaires were collected. Using structural equation modeling, this study finds that the direct effects of shopping values on shopping behavior are stronger than their indirect effects through attitudes. Compared with utilitarian shopping values, hedonic shopping values exert a stronger effect on airport shopping behavior, implying that airport shopping involves more multisensory decisions than cognitive decisions. In addition, avoiding negative feelings (e.g. regret) appears to be a stronger antecedent of airport shopping behavior than pursuing positive feelings (e.g. excitement). Marketing strategies of airport retailing are discussed. (C) 2015 Elsevier Ltd. All rights reserved.
Development of lattice-inserted 5-Fluorouracil-hydroxyapatite nanoparticles as a chemotherapeutic delivery system
(2015-10-01)
Tseng, Ching-Li
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Chen, Jung-Chih
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Wu, Yu-Chun
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Fang, Hsu-Wei
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Lin, Feng-Huei
Developing an effective vehicle for cancer treatment, hydroxyapatite nanoparticles were fabricated for drug delivery. When 5-Fluorouracil, a major chemoagent, is combined with hydroxyapatite nanocarriers by interclay insertion, the modified hydroxyapatite nanoparticles have superior lysosomal degradation profiles, which could be leveraged as controlled drug release. The decomposition of the hydroxyapatite nanocarriers facilitates the release of 5-Fluorouracil into the cytoplasm causing cell death. Hydroxyapatite nanoparticles with/without 5-Fluorouracil were synthesized and analyzed in this study. Their crystallization properties and chemical composition were examined by X-ray diffraction and Fourier transforms infrared spectroscopy. The 5-Fluorouracil release rate was determined by UV spectroscopy. The biocompatibility of hydroxyapatite-5-Fluorouracil extraction solution was assessed using 3T3 cells via a WST-8 assay. The effect of hydroxyapatite-5-Fluorouracil particles which directly work on the human lung adenocarcinoma (A549) cells was evaluated by a lactate dehydrogenase assay via contact cultivation. A 5-Fluorouracil-absorbed hydroxyapatite particles were also tested. Overall, hydroxyapatite-5-Fluorouracils were prepared using a co-precipitation method wherein 5-Fluorouracil was intercalated in the hydroxyapatite lattice as determined by X-ray diffraction. Energy dispersive scanning examination showed the 5-Fluorouracil content was higher in hydroxyapatite-5-Fluorouracil than in a prepared absorption formulation. With 5-Fluorouracil insertion in the lattice, the widths of the a and c axial constants of the hydroxyapatite crystal increased. The extraction solution of hydroxyapatite-5-Fluorouracil was nontoxic to 3T3 cells, in which 5-Fluorouracil was not released in a neutral phosphate buffer solution. In contrast, at a lower pH value (2.5), 5-Fluorouracil was released by the acidic decomposition of hydroxyapatite. Finally, the results of the lactate dehydrogenase assay revealed that 5-Fluorouracil-hydroxyapatite was highly toxic to A549 cells through direct culture, this phenomenon may result from lysosomal decomposition of particles causing 5-Fluorouracil releasing. The pH-responsive hydroxyapatite-5-Fluorouracil nanoparticles have the potential to be part of a selective drug-delivery system in chemotherapy for cancer treatment.
Reducing wireless multi-hop delay via RSU re-routing in vehicular wireless networks
(2015-10-01)
Wang, Kuo-Lung
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Wang, Tsan-Pin
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Tseng, Chien-Chao
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資訊工程學系
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Department of Computer Science
Vehicular wireless networks offer wireless multi-hop communications between vehicles and roadside units (RSUs). To reduce deployment cost, the distance between two RSUs could be long; that is,the communications between an RSU and a vehicle may be carried out through multi-hops among intermediate vehicles. When a vehicle is driven from one RSU to another, the wireless multi-hop delay becomes more serious as the number of multi-hop relays increases. The wireless multi-hop delay is critical for some emergency service. For instance, in a traffic accident, when a patient was sent to the hospital by ambulance, the life information of the patient must be transmitted to the hospital on time through the multi-hop wireless network. If the ambulance is moved from one RSU to another, the wireless multi-hop delay becomes more and more serious as the ambulance is closing to another RSU. In this paper, we propose an RSU re-routing strategy that dynamically alters multi-hop communications until the best RSU with the shortest path using location information is found. Moreover, we compare the proposed strategy with the existing strategy in terms of broadcasting costs, re-routing delay, and wireless multi-hop delay of data transmission. Performance results show that the proposed strategy can reduce the wireless multi-hop delay significantly. Copyright (c) 2014 John Wiley & Sons, Ltd.
Quantiferon TB-Gold conversion can predict active tuberculosis development in elderly nursing home residents
(2015-10-01)
Tsou, Ping-Hsien
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Huang, Wei-Chang
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Huang, Chen-Cheng
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Lin, Chen-Fu
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Wu, Kun-Ming
AimThe study was carried out on elderly nursing home residents in Taiwan. We assessed whether the serial QuantiFERON-TB Gold (QFT-G) assay and serial tuberculin skin test (TST) were reliable tools to predict or exclude the development of active tuberculosis (TB). MethodsThis prospective observational cohort study involved non-bacillus Calmette-Guerin-vaccinated 259 elderly nursing home residents free of active TB at baseline. Of these, 147 were eligible for follow up. Participants underwent serial QFT-G and TST at baseline and 2-year follow up, and were monitored for active TB over 5years. Agreement between QFT-G and TST, incidence rate ratio, positive predictive value, and negative predictive value for progression to active TB were measured. ResultsDuring 5-year follow up, three participants developed active TB. The agreement between these two tests was 54.13% (?=0.167, P=0.001). The incidence rate ratio was 15.8 (P=0.016) for the QFT-G-conversion group compared with the TST-positive group at baseline. Positive predictive value for QFT-G conversion groups was 25%. Negative predictive value was 100% for the TST-negative group at baseline. ConclusionIn the elderly nursing home residents, QFT-G conversion is a more reliable tool to predict the development of active TB. Meanwhile, TST is a valuable tool for predicting the chance of not developing active TB. Geriatr Gerontol Int 2015; 15: 1179-1184.
Optical and thermal design of light emitting diodes omnidirectional bulb
(2015-10-01)
Ye, Zhi Ting
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Kuo, Hao-Chung
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Chen, Cheng-Huan
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光電工程學系
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Department of Photonics
The penetration of LED light bulbs into the lighting market is growing quickly in recent years due to significant increase of LED efficiency and reduction of cost. One major issue to be improved is the overall light bulb efficiency, which can fulfill "Energy Star for Lamps" while keeping sufficiently high efficiency. The efficiency issue results mainly from the high directionality of the LED sources and the corresponding solutions to make the emission more diverse. In this paper, a diffusion white reflection sheet (DWRS) with an array of holes is proposed as a high efficiency solution for modulating a light emission profile with SMD type LED source. The hole size is adjusted with fixed hole pitch to both maximize the efficiency and meet the omnidirectional specification. In addition, the concept of thermal plastic insertion molding metal is proposed for thermal management without fins for cooling. The prototype demonstrates the efficiency (Ef.) of 87.6% and LED pad temperature of 85 degrees C, which shows the feasibility as a total solution for high efficiency LED omnidirectional bulbs. (C) 2015 Optical Society of America
Performance of bare-tube bundle having small diameter tube: With and without partial bypass
(2015-10-01)
Chang, Neng-Chieh
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Li, Chao-Jen
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Wang, Chi-Chuan
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機械工程學系
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Department of Mechanical Engineering
The present study experimentally investigates the air-side performance of the staggered bare tube bundle having a small diameter tube in association with the partial bypass design. A total of ten arrangements are made and tested with corresponding surface reduction of 5%, 10%, and 20%, respectively. The measured heat transfer and pressure drop results of the conventional bare tube bundle agree well with the existing predictions. For the typical tube bundle, both heat transfer rate and heat transfer coefficient (HTC) first increase with the tube row and peaks at the fourth row. The HTC then remains almost unchanged when the tube row is further increased. Through the partial bypass designs, the front part of the tube bundle suffers some heat losses for having some fewer available surfaces but the rear part of the tube bundle will achieve a higher heat transfer rate for a higher temperature difference. The phenomenon of losing heat transfer in the front part but gaining performance in the rear part becomes more pronounced with the surface area reduction. For the partial bypass design with the same area reduction, it appears that the vertical reduction designs are marginally better than those lateral reduction designs. For comparisons of the effective thermal resistance subject to the same pumping power. It is clearly seen that the convectional design still outperforms all partial designs. As the pumping power becomes larger, the performance of the "partial bypass" designs are slowly and gradually improved to close to the traditional tube bundle. The difference is comparative small with the 5% and 10% "partial bypass" design. This trend indicates that the "partial bypass" is more beneficial at the operating condition of higher pumping power especially for the 5% surface reduction design. (C) 2015 Elsevier Ltd. All rights reserved.
Guest Editorial: Multimedia Applications for Smart device and Equipment
(2015-10-01)
Kim, Tai-hoon
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Mohammed, Sabah
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Ramos, Carlos
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Fang, Wai-Chi
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交大名義發表
A dynamic data driven-based semi-distributed reputation mechanism in unknown networks
(2015-10-01)
Lin, Szu-Yin
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Chou, Ping-Hsien
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
Trust is a crucial concern related to unknown networks. A mechanism that distinguishes trustworthy and untrustworthy nodes is essential. The effectiveness of the mechanism depends on the accuracy of a node\'s reputation. The dynamics of trust often occurs in a trusted network and causes intoxication and disguises of the nodes, resulting in abnormal behaviors. This study proposes a semi-distributed reputation mechanism based on a dynamic data-driven application system. This mechanism includes two reputations, local reputation (LRep) and global reputation (GRep). LRep is dynamically and selectively injected into a central controller, and this controller collects the injected data to compute GRep, which contains the neural network prediction method, and returns it to provide reference to the distributed nodes. The proposed mechanism focuses on dynamics of trust and the balance between distributed nodes and the central controller. Experimental results showed that GRep was computable with only 52.21% (average) LReps upload and that GRep increased or reduced by 26.5% (average) in a short period, demonstrating that the proposed mechanism effectively handles the problem of dynamics of trust. (C) 2015 Elsevier B.V. All rights reserved.
GaN Layers on Si (111) from Nanocolumns to Nanorods by Plasma-Assisted Molecular Beam Epitaxy
(2015-10)
Yu, Ing-Song
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Liang, Wen-Han
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Yang, Dian-Long
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Yang, Chung-Pei
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Chang, Chun-Pu
In this report, the characterization of GaN layers grown on p-type Si (111) substrate by plasma-assisted molecular beam epitaxy was investigated. For different growth temperatures (750 degrees C, 800 degrees C and 850 degrees C) and N/Ga flux ratios (0.26, 0.46 and 0.92), we can find the GaN layers transition from nanocolumns to nanorods structures. During the epitaxy of GaN, nanocolumns in the thin films with poor crystal quality were obtained for the growth parameters of low substrate temperature or Ga-rich condition. However, the growth at high substrate temperature or N-rich condition formed GaN nanorods structure, and was beneficial to the crystallization of GaN layers with preferential orientation (0001). In the end, the possible growth mechanism of GaN nanocolumns and nanorods was discussed in the letter.