Browsing by Issue Date, starting with "2017-02-20"

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交大e-News第226期-機車遊行嘉年華 2017年丁酉梅竹賽系列活動開跑
(2017-02-20)
國立交通大學秘書室
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Secretariat
Polarization- selective ultra-broadband super absorber
(2017-02-20)
Zhong, Yan Kai
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Fu, Sze Ming
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Huang, Weiming
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Rung, Ding
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Huang, Jian Yi-Wen
While a broadband metamaterial perfect absorber (MPA) has been implemented and proposed intensively in recent years, an ultra-broadband perfect absorber with polarization selectivity has not been realized in literature. In this work, we propose a configuration of polarization-selective (PS) MPA with ultra-wide absorption bandwidth. The aluminum wire grid is integrated on top of the ultrathin-metal-dielectric stacking. The transverse electric (TE) wave is blocked due to the requirement of zero tangential electric field at the metal surface. The transverse magnetic field can pass the aluminum wire-grids because the normal electric field can be supported by the surface charge density at the metal surface, and full absorption of the TM wave is accomplished by the metal-dielectric stacking beneath. Theoretical calculation using rigorously coupled wave analysis demonstrates the wavelength selectivity from lambda = 1.98 mu m to lambda = 11.74 mu m where the TE absorption is <0.04 while TM absorption is >0.95, using 300 nm thick aluminum (Al) wire grid with 16-pair SiO2/Ti stacking. Additionally, the design is wavelength scalable by adjusting the dielectric thickness (t(sio2)) and the wire grid period (P) and height (t). The experimental result is demonstrated using Al grids and Ti/SiO2, and the measured result fully supports the calculated prediction. (C) 2017 Optical Society of America
Recombination Pathways in Green InGaN/GaN Multiple Quantum Wells
(2017-02-21)
Lin, Tao
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Kuo, Hao Chung
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Jiang, Xiao Dong
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Feng, Zhe Chuan
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光電工程學系
This paper reports the transient photoluminescence (PL) properties of an InGaN/GaN multiple quantum well (MQW) light-emitting diode (LED) with green emission. Recombination of localized excitons was proved to be the main microscopic mechanism of green emission in the sample. The PL dynamics were ascribed to two pathways of the exciton recombination, corresponding to the fast decay and the slow decay, respectively. The origins of slow decay and fast decay were assigned to local compositional fluctuations of indium and thickness variations of InGaN layers, respectively. Furthermore, the contributions of two decay pathways to the green PL were found to vary at different emission photon energy. The fraction of fast decay pathway decreased with decreasing photon energy. The slow radiative PL from deep localized exciton recombination suffered less suppression from non-radiative delocalization process, for the higher requested activation energy. All these results supported a clear microscopy mechanism of excitation-emission process of the green MQW LED structure.
Extracting trajectory equations of classical periodic orbits from the quantum eigenmodes in two-dimensional integrable billiards
(2017-02-21)
Hsieh, Y. H.
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Yu, Y. T.
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Tuan, P. H.
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Tung, J. C.
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Huang, K. F.
The trajectory equations for classical periodic orbits in the equilateral-triangular and circular billiards are systematically extracted from quantum stationary coherent states. The relationship between the phase factors of quantum stationary coherent states and the initial positions of classical periodic orbits is analytically derived. In addition, the stationary coherent states with noncoprime parametric numbers are shown to correspond to the multiple periodic orbits, which cannot be explicable in the one-particle picture. The stationary coherent states are further verified to be linked to the resonant modes that are generally observed in the experimental wave system excited by a localized and unidirectional source. The excellent agreement between the resonant modes and the stationary coherent states not only manifests the importance of classical features in experimental systems but also paves the way to manipulate the mesoscopic wave functions localized on the periodic orbits for applications.
Ag Doping of Organometal Lead Halide Perovskites: Morphology Modification and p-Type Character
(2017-02-23)
Shahbazi, Saeed
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Tsai, Cheng-Min
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Narra, Sudhakar
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Wang, Chi-Yung
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Shiu, Hau-Shiang
We report a simple synthetic approach to grow uniform CH3NH3PbI3 perovskite (PSK) layers free of pinholes via ciE varied portions of silver iodide (AgI) added to the precursor solution. XRD/EDS elemental mapping experiments demonstrated nearly uniform Ag distribution inside the perovskite film. When the 1% AgI- assisted perovskite films were fabricated into a p-i-n planar device, the a) photovoltaic performance was enhanced by similar to 30% (PCE increased from 9.5% to 12.0%) relative to the standard cell without added AgI. . Measurement of electronic properties using a hall setup indicated that perovskite films show p-type character after Ag doping, whereas the film is n-type without Ag. Transients of photoluminescence of perovskite films with and without AgI additive deposited on glass, p-type (PEDOT:PSS), and n-type (TiO2) contact layers were recorded with a time-correlated single-photon counting (TCSPC) technique. The TCSPC results indicate that addition of AgI inside perovskite in contact with PEDOT:PSS accelerated the hole-extraction motion whereas that in contact with TiO2 led to a decelerated electron extraction, in agreement with the trend observed from the photovoltaic results. The silver cationic dopant inside the perovskite films had hence an effect of controlling the morphology to improve photovoltaic performance for devices with p-i-n configuration.
The electronic structure, optical absorption and photocatalytic water splitting of (Fe plus Ni)-codoped TiO2: A DFT + U study
(2017-02-23)
Lin, Yanming
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Jiang, Zhenyi
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Zhu, Chaoyuan
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Zhang, Ruiqin
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Hu, Xiaoyun
The electronic and optical properties of Fe or/and Ni (co)doped anatase and rutile TiO2 were investigated using the spin-polarized density functional theory. Our calculated results indicate that the synergistic effect of (Fe + Ni) codoping can lead to a band gap narrowing and the hybridized states of Fe 3d and Ni 3d appearing in the forbidden gap, which enhances greatly the optical absorption of TiO2 nanomaterials from the ultraviolet-light to the infrared-light region and reduces the recombination of photogenerated electron hole pairs. In particular, (Fe + Ni) codoping can improve greatly the infrared-light absorption of TiO2 nanomaterials. Furthermore, the researches of electronegativity show that (Fe + Ni)codoped TiO2 system has a stronger redox power for hydrogen generation by photo catalytic water splitting compared with pure, Fe-doped, and Ni-doped TiO2 systems. These results lead to an outstanding solar energy photocatalytic water splitting for hydrogen generation in (Fe + Ni)-codoped TiO2 photocatalyst. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Honeysuckle aqueous extract and induced let-7a suppress dengue virus type 2 replication and pathogenesis
(2017-02-23)
Lee, Ying-Ray
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Yeh, Siao-Fen
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Ruan, Xiao-Ming
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Zhang, Hao
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Hsu, Sheng-Da
Ethnopharmacological relevance: Honeysuckle (Lonicera japonica Thunb.), a traditional Chinese herb, has widely been used to treat pathogen infection. However, the underlying-mechanism remains elusive. Aims of the study: To reveal the host microRNA (miRNA) profile with the anti-viral activity after honeysuckle treatment. Materials and methods: Here we reveal the differentially expressed miRNAs by Solexa (R) deep sequencing from the blood of human and mice after the aqueous extract treatment. Among these overexpressed innate miRNAs both in human and mice, let-7a is able to target the NS1 region (nt 3313-3330) of dengue virus (DENV) serotypes 1, 2 and 4 predicated by the target predication software. Results: We confirmed that let-7a could target DENV2 at the predicated NS1 sequence and suppress DENV2 replication demonstrated by luciferase-reporter activity, RT-PCR, real-time PCR, Western blotting and plaque assay. ICR-suckling mice consumed honeysuckle aqueous extract either before or after intracranial injection with DENV2 showed decreased levels of NS1 RNA and protein expression accompanied with alleviated disease symptoms, decreased virus load, and prolonged survival time. Similar results were observed when DENV2infected mice were intracranially injected with let-7a. Conclusion: We reveal that honeysuckle attenuates DENY replication and related pathogenesis in vivo through induction of let-7a expression. This study opens a new direction for prevention and treatment of DENY infection through induction of the innate miRNA let-7a by honeysuckle.
Nonlocal electrodynamics in Weyl semimetals
(2017-02-28)
Rosenstein, B.
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Kao, H. C.
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Lewkowicz, M.
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電子物理學系
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Department of Electrophysics
Recently synthesized three-dimensional materials with Dirac spectrum exhibit peculiar electric transport qualitatively different from its two-dimensional analog, graphene. By neglecting impurity scattering, the real part of the conductivity is strongly frequency dependent, while the imaginary part is nonzero unlike in undoped, clean graphene. The Coulomb interaction between electrons is unscreened as in a dielectric and hence is long range. We demonstrate that the interaction correction renders the electrodynamics nonlocal on a mesoscopic scale. The longitudinal conductivity sigma(L) and the transverse conductivity sigma(T) are different in the long-wavelength limit and consequently the standard local Ohm's law description does not apply. This leads to several remarkable effects in optical response. The p-polarized light generates in these materials bulk plasmons as well as the transversal waves. At a specific frequency the two modes coincide, a phenomenon impossible in a local medium. For any frequency there is a Brewster angle where total absorption occurs, turning the Weyl semimetals opaque. The effect of the surface, including the Fermi arcs, is discussed.
Time periodic saturated flow boiling heat transfer of R-134a in a narrow annular duct due to heat flux oscillation
(2017-03)
Chen, C. A.
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Lin, T. F.
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Yan, Wei-Mon
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機械工程學系
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Department of Mechanical Engineering
The time periodic saturated boiling heat transfer in a horizontal annulus was investigated experimentally where the walls are under an oscillating heat flux. The fluid enters the duct with zero vapor quality (saturated liquid state). The amplitude of the imposed heat flux oscillation Delta q varies from 0% to 50% of mean imposed heat flux (q) over bar and four different periods of heat flux oscillation t(p) including 20, 30, 60 and 120 s are applied to the system. The measured data display that when the applied heat flux is close to that for the onset of stable flow boiling, intermittent flow boiling appears in which nucleate boiling on the heated surface only exists in a partial interval of each periodic cycle and the heat flux oscillation does not noticeably affect the time-average boiling curves and heat transfer coefficients. Besides, the heated wall temperature and evaporating flow pattern are found to oscillate periodically in time as well and at the same frequency as the imposed heat flux oscillation. Furthermore, in the persistent boiling the resulting oscillation amplitudes of the heated surface temperature, heat transfer coefficient gets larger for a longer period and larger amplitude of the imposed heat flux oscillation and for a higher mean imposed heat flux. The substantial time lag in the heated surface temperature oscillation is observed. In the first half of the periodic cycle in which the heat flux reduces with time, after the time lag the heated wall temperature decreases with time. The inverse processes occur in the second half of the cycle in which imposed heat flux increases with time. Finally, flow regime maps are provided to explain the boundaries separating different boiling regimes for the R-134a saturated boiling in the duct. (C) 2016 Elsevier Ltd. All rights reserved.
Only-One-Victor Pattern Learning in Computer Go
(2017-03-01)
Wang, Jiao
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Xiao, Chenjun
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Zhu, Tan
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Hsueh, Chu-Husan
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Tseng, Wen-Jie
Automatically acquiring domain knowledge from professional game records, a kind of pattern learning, is an attractive and challenging issue in computer Go. This paper proposes a supervised learning method, by introducing a new generalized Bradley-Terry model, named Only-One-Victor, to learn patterns from game records. Basically, our algorithm applies the same idea with Elo rating algorithm, which considers each move in game records as a group of move patterns, and the selected move as the winner of a kind of competition among all groups on current board. However, being different from the generalized Bradley-Terry model for group competition used in Elo rating algorithm, Only-One-Victor model in our work simulates the process of making selection from a set of possible candidates by considering such process as a group of independent pairwise comparisons. We use a graph theory model to prove the correctness of Only-One-Victor model. In addition, we also apply the Minorization-Maximization (MM) to solve the optimization task. Therefore, our algorithm still enjoys many computational advantages of Elo rating algorithm, such as the scalability with high dimensional feature space. With the training set containing 115,832 moves and the same feature setting, the results of our experiments show that Only-One-Victor outperforms Elo rating, a well-known best supervised pattern learning method.
A Model for Neutral Defect Limited Electron Mobility in Strained-Silicon Inversion Layers
(2017-03-01)
Hsieh, Shang-Hsun
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Chen, Ming-Jer
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
On the strained silicon metal-oxide-semiconductor field-effect transistors (MOSFETs), we show how to derive a formalism dealing with the scattering of a 2-D electron by a neutral defect. The corresponding neutral defect limited inversion-layer electron mobility, mu(n), is calculated in the momentum relaxation time approximation. The calculated results lead to a new analytical model: mu(n) = cN(n)(-1) where N-n is the neutral defect density per unit area and c is the coefficient independent of the inversion-layer density, the strain, and the temperature. The validity and applicability of the model are confirmed by citing three independent experiments on strained silicon MOSFETs undergoing different implantation sources and different annealing budgets. Importantly, this paper clarifies for the first time that strain will not change neutral defect limited mobility unless changing the neutral defect density. This reasonably explains the two experimental observations during implantation and annealing: 1) the implantation-induced strain relaxation in strained sample does not occur and 2) the neutral defect density is much higher in strained sample than in unstrained sample.
Soft-Boosted Self-Constructing Neural Fuzzy Inference Network
(2017-03)
Prasad, Mukesh
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Lin, Chin-Teng
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Li, Dong-Lin
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Hong, Chao-Tien
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Ding, Wei-Ping
This correspondence paper proposes an improved version of the self-constructing neural fuzzy inference network (SONFIN), called soft-boosted SONFIN (SB-SONFIN). The design softly boosts the learning process of the SONFIN in order to decrease the error rate and enhance the learning speed. The SB-SONFIN boosts the learning power of the SONFIN by taking into account the numbers of fuzzy rules and initial weights which are two important parameters of the SONFIN, SB-SONFIN advances the learning process by: 1) initializing the weights with the width of the fuzzy sets rather than just with random values and 2) improving the parameter learning rates with the number of learned fuzzy rules. The effectiveness of the proposed soft boosting scheme is validated on several real world and benchmark datasets. The experimental results show that the SB-SONFIN possesses the capability to outperform other known methods on various datasets.
Novel non-contact control system of electric bed for medical healthcare
(2017-03-01)
Lo, Chi-Chun
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Tsai, Shang-Ho
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Lin, Bor-Shyh
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影像與生醫光電研究所
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電控工程研究所
A novel non-contact controller of the electric bed for medical healthcare was proposed in this study. Nowadays, the electric beds are widely used for hospitals and home-care, and the conventional control method of the electric beds usually involves in the manual operation. However, it is more difficult for the disabled and bedridden patients, who might totally depend on others, to operate the conventional electric beds by themselves. Different from the current controlling method, the proposed system provides a new concept of controlling the electric bed via visual stimuli, without manual operation. The disabled patients could operate the electric bed by focusing on the control icons of a visual stimulus tablet in the proposed system. Besides, a wearable and wireless EEG acquisition module was also implemented to monitor the EEG signals of patients. The experimental results showed that the proposed system successfully measured and extracted the EEG features related to visual stimuli, and the disabled patients could operate the adjustable function of the electric bed by themselves to effectively reduce the long-term care burden.
Is immersion of any value? Whether, and to what extent, game immersion experience during serious gaming affects science learning
(2017-03)
Cheng, Meng-Tzu
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Lin, Yu-Wen
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She, Hsiao-Ching
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Kuo, Po-Chih
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教育研究所
Many studies have shown the positive impact of serious gaming on learning outcomes, but few have explored the relationships between game immersion and science learning. Accordingly, this study was conducted to investigate the effectiveness of learning by playing, as well as the dynamic process of game immersion experiences, and to further identify whether, and to what extent, immersion affects science learning through serious gaming by using the techniques of cluster analysis. A total of 63 seventh-grade students participated in the study, and a quasi-experimental research design was employed. The results demonstrated that the students gained a holistic understanding of the relevant scientific concepts because their performances on the scenario-based science assessment were significantly improved across serious gameplaying occasions, and the effect of learning was retained long term. Moreover, serious gaming provided students with the experience of immersion insofar as the students indicated a greater degree of immersion in the game over time. Furthermore, two core clusters presenting meaningful patterns, high gaming performance/high immersion and high science learning/low immersion, were revealed. Finally, various interpretations and implications of the obtained data are discussed.
Determinants of profiting from innovation activities: Comparisons between technological leaders and latecomers
(2017-03-01)
Hu, Mei-Chih
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Kang, Jin-Su
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Wu, Ching-Yan
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經營管理研究所
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Institute of Business and Management
While the remarkable economic growth of the East Asian latecomers reflects the success of technological catching-up strategies, few researchers have explored the extent to which the profits of innovation have been created and managed in their social contexts and how those profits are secured differently from that of technological leaders. This pioneer study offers empirical evidence and insights by exploring how different rents (value) were secured within the existing global technological regime by technological leaders and by latecomers over the period 1990 to 2009. Our results demonstrate that technological regimes, including technological congruence and social capabilities, affect technological leaders and latecomers in different ways resulting in a relationship where the two play complementary roles. The accumulation and utilization of social capabilities are essential for developing state-of-the-art technologies and securing profit from innovations in the global market. The insights and implications for both technological leaders and latecomers are discussed and elaborated. (C) 2016 Elsevier Inc. All rights reserved.
利用高維度子空間產生取樣之方法
(2017-03-01)
林進燈
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謝宗佑
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劉宇庭
本發明係為一種利用高維度子空間產生取樣之方法，包括將一向量資料值投影至複數高維度子空間上，以產生複數向量子空間資料值，並取其中具有最大值之向量子空間資料值為最佳向量子空間資料值，並取其所屬子空間的維度，設為基準維度並利用梯度演算，調整其餘子空間，以產生新高維度子空間，再投影出新向量子空間資料值，判斷新向量子空間資料值與向量資料值之比值是大於或等於一預設值，若是，新向量子空間資料值則成為取樣值，若否，則回覆至第一步驟。故，本發明可產生與原始資料相似的取樣資料。
自適性（ａｄａｐｔｉｖｅ）生理反應之參數預測方法及其預測裝置
(2017-03-01)
林進燈
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莊鈞翔
本發明係揭露一種自適性(adaptive)生理反應之參數預測方法及其預測裝置，首先，在生理狀態判斷流程中，先接收一生理資料與一第一生理訊號，據此計算出分別對應複數不同程度之生理狀態之複數生理權重值，生理權重值的總和等於1。然後，執行複數次預測流程，在每一預測流程中，係先接收一第二生理訊號，並據此計算出分別對應不同程度之生理狀態的複數生理反應值。接著，運算生理反應值與生理權重值，以產生一生理反應參數來完成預測流程。在完成複數次預測流程後，則會執行一次生理狀態判斷流程以更新生理權重值，藉此針對各種不同程度之生理狀態的使用者取得精準的預測結果。
Characterization of Temporary Bonding and Laser Release Using Polyimide and a 300-nm Photolysis Polymer System for High-Throughput 3-D IC Applications
(2017-03)
Cheng, Chuan-An
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Tsai, Tsung-Yen
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Huang, Yu-Hsiang
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Lin, Chien-Hung
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Lee, Chia-Lin
A new temporary bonding technology with an ultrafast laser-release process of less than 20 s is presented, where a 300-nm-thick photolysis polymer and polyimide are served as the release layer and adhesive layer, respectively. The submicrometer-thick polymer has the feature of high absorption of a 355-nm laser in contrast to polyimide during debonding procedures. In addition, the thin release layers of high chemical resistance and mechanical strength demonstrate their feasibility for handling process. Electrical characteristics of the devices before and after the laser-release process are investigated, showing no degradation. Thus, this technology scheme demonstrates its potential for temporary bonding and release in 3-D integration applications.
Unusual Emission of Polystyrene-Based Alternating Copolymers Incorporating Aminobutyl Maleimide Fluorophore-Containing Polyhedral Oligomeric Silsesquioxane Nanoparticles
(2017-03-01)
Mohamed, Mohamed Gamal
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Jheng, Yu-Ru
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Yeh, Shu-Ling
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Chen, Tao
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Kuo, Shiao-Wei
In this study, we synthesized an unusual 2-aminobutyl maleimide isobutyl polyhedral oligomeric silsesquioxane (MIPOSS-NHBu) monomer lacking conventional fluorescent groups. We then prepared poly(styrene-alt-2-aminobutyl maleimide isobutyl POSS) [poly(S-alt-MIPOSS-NHBu)] and poly(4-acetoxystyrene-alt-2-aminobutyl maleimide isobutyl POSS) [poly(AS-alt-MIPOSS-NHBu)] copolymers through facile free radical copolymerizations using azobisisobutyronitrile as the initiator and tetrahydrofuran as the solvent. A poly(4-hydroxystyrene-alt-2-aminobutyl maleimide isobutyl POSS) [poly(HS-alt-MIPOSS-NHBu)] copolymer was prepared through acetoxyl hydrazinolysis of poly(AS-alt-MIPOSS-NHBu). We employed H-1, C-13, and Si-29 nuclear magnetic resonance spectroscopy; Fourier transform infrared spectroscopy; differential scanning calorimetry; and photoluminescence spectroscopy to investigate the structures and the thermal and optical properties of the monomers and novel POSS-containing alternating copolymers. Intramolecular hydrogen bonding between the amino and dihydrofuran-2,5-dione group and clustering of the locked C = O groups from the POSS nanoparticles in the MIPOSS-NHBu units restricted the intramolecular motion of the polymer chain, causing it to exhibit strong light emission. As a result, the MIPOSS-NHBu monomer and the poly(AS-alt-MIPOSS-NHBu) copolymer both have potential applicability in the detection of metal ions with good selectivity.
Damage detection of structures with detrended fluctuation and detrended crosscorrelation analyses
(2017-03-01)
Lin, Tzu-Kang
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Fajri, Haikal
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土木工程學系
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Department of Civil Engineering
Recently, fractal analysis has shown its potential for damage detection and assessment in fields such as biomedical and mechanical engineering. For its practicability in interpreting irregular, complex, and disordered phenomena, a structural health monitoring (SHM) system based on detrended fluctuation analysis (DFA) and detrended cross-correlation analysis (DCCA) is proposed. First, damage conditions can be swiftly detected by evaluating ambient vibration signals measured from a structure through DFA. Damage locations can then be determined by analyzing the cross correlation of signals of different floors by applying DCCA. A damage index is also proposed based on multi-scale DCCA curves to improve the damage location accuracy. To verify the performance of the proposed SHM system, a four-story numerical model was used to simulate various damage conditions with different noise levels. Furthermore, an experimental verification was conducted on a seven-story benchmark structure to assess the potential damage. The results revealed that the DFA method could detect the damage conditions satisfactorily, and damage locations can be identified through the DCCA method with an accuracy of 75%. Moreover, damage locations can be correctly assessed by the damage index method with an improved accuracy of 87.5%. The proposed SHM system has promising application in practical implementations.