Browsing by Issue Date, starting with "2012-07-19"

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Electroabsorption and Electrophotoluminescence of Poly(2,3-diphenyl-5-hexyl-p-phenylene vinylene)
(2012-07-19)
Mehata, Mohan Singh
;
Hsu, Chain-Shu
;
Lee, Yuan-Pern
;
Ohta, Nobuhiro
;
應用化學系
Electric-field-induced changes of the absorption, photoluminescence, and photoluminescence excitation spectra and the photoluminescence decay profile have been measured for poly(2,3-diphenyl-5-hexyl-p-phenylene vinylene). The magnitudes of the change of electric dipole moment and molecular polarizability of this compound have been determined for excitation into the first excited state having a strong absorption, and a large charge-separated character, which is relevant for photovoltaic devices, is confirmed. The photoluminescence of this compound is quenched by application of an electric field, and the quenching efficiency increases with decreasing excitation wavelength. Field-assisted dissociation is considered to occur from the photoexcited Franck-Condon state, resulting in the field-induced decrease in the population of the emitting state, which induce the quenching of photoluminescence.
Frame Prediction System and Prediction Method Thereof
(2012-07-19)
PENG WEN-HSIAO
;
CHEN YI-WEN
The present invention discloses a frame prediction system and a prediction method thereof. An initializing module initializes a first image block having a plurality of pixels. A providing module provides a first centroid and a first motion vector of a second image block. The location lookup module finds a location according to the first centroid, and generates a first weight and a second weight respectively according to a relationship between each of the pixels, the first centroid and the location. A vector lookup module finds a second motion vector, which gives a minimum pixel intensity error for the plurality of pixels in the first image block according to the first centroid, the first motion vector, the location, the first weight and the second weight. A processing module sequentially calculates a plurality of predictive intensity values according to the motion vectors and the weights.
Method for smoothing group lll nitride semiconductor substrate
(2012-07-19)
Lee Wei-I
;
Chen Kuei-Ming
;
Wu Yin-Hao
;
Yeh Yen-Hsien
The invention discloses a smoothing method to decrease bowing of group III nitride semiconductor substrate. The certain face of group III nitride semiconductor substrates is etched under the appropriate etching recipe and time, the certain morphology such as rod-type and other structures are appeared at the certain face. And such structures releases the compressive stresses at these certain faces, resulting in clearly increasing the bowing radius of the group III nitride semiconductor substrates, finally decreasing the bowing phenomenon of the group III nitride semiconductor substrate.
Fracture responses of microstructures of electron beam-welded D6AC
(2012-07-20)
Wu, Shyh-Chi
;
Wen, Hua-Chiang
;
Wu, Ming-Jhang
;
Chou, Chang-Pin
;
機械工程學系
In this study, D6AC steel was produced from flow forming (wall thickness reduction: 67%) and then it was subjected to electron beam welding and tempering treated. We characterized the specimens in terms of their microstructures and nanotribological properties. After tempering treatment at 315 degrees C, the yield strength increased from 381 to 1334 MPa and the percentage elongation increased remarkably from 0.5 to 7.8%. We performed these mechanical studies for the samples subjected to each set of experimental conditions, and determined the tribological characteristics from the heat-affected zone and the fusion zone. Lower degrees of adhesion reflected the presence of interlinks and rearrangements of indenter tip at lateral force that have been responsible for fluctuations in the coefficients of friction. (C) 2012 Elsevier Ltd. All rights reserved.
交大e-News第122期
(2012-07-20)
Secretariat
;
國立交通大學秘書室
A novel peristaltic micropump with low compression ratios
(2012-07-20)
Tsui, Yeng-Yung
;
Chang, Tso-Chang
;
機械工程學系
;
Department of Mechanical Engineering
It is common for peristaltic micropumps to have large compression ratios. In the limit, the chamber of the pump is completely blocked by the membrane to prevent back flow. Different from this kind of pump, a micropump with small compression ratios is proposed in this study. With small oscillation amplitudes the membrane of the pump can reciprocate at high frequencies to improve its pumping flow. Both the multidimensional method and the lumped-element method are employed for analysis. For this kind of peristaltic micropump the working fluid is allowed to flow freely in the forward and backward directions. Therefore, the operating sequences for the high-compression ratio type of pumps are not appropriate. It is shown that the theoretical net flow rate is zero for the four-phase and six-phase modes of sequence and becomes negative for the three-phase mode unless regulators, such as the nozzle/diffusers, are incorporated to rectify the flow. However, this pump becomes very attractive by reversing the operating sequence of the three-phase mode because positive net flow is yielded. It is seen that with the reversed three-phase mode and the nozzle/diffuser as connecting channels, the pumping effectiveness is greatly enhanced. The pumps with both two chambers and three chambers are under consideration in the study. Copyright (c) 2011 John Wiley & Sons, Ltd.
顯示器
(2012-07-21)
范士岡
;
邱誠樸
;
莫啟能
;
江美昭
一種顯示器包括一第一基板、一第一電極、一第二基板、一第二電極與一混合溶液。其中，第一電極配置於第一基板上，而第二電極配置於第二基板上。此外，混合溶液配置於第一電極與第二電極之間。本發明之混合溶液包括一溶液與多個配置於溶液中之第一中性微粒子。
Evidence of Sharp and Diffuse Domain Walls in BiFeO3 by Means of Unit-Cell-Wise Strain and Polarization Maps Obtained with High Resolution Scanning Transmission Electron Microscopy
(2012-07-25)
Lubk, A.
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Rossell, M. D.
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Seidel, J.
;
He, Q.
;
Yang, S. Y.
Domain walls (DWs) substantially influence a large number of applications involving ferroelectric materials due to their limited mobility when shifted during polarization switching. The discovery of greatly enhanced conduction at BiFeO3 DWs has highlighted yet another role of DWs as a local material state with unique properties. However, the lack of precise information on the local atomic structure is still hampering microscopical understanding of DW properties. Here, we examine the atomic structure of BiFeO3 109 degrees DWs with pm precision by a combination of high-angle annular dark-field scanning transmission electron microscopy and a dedicated structural analysis. By measuring simultaneously local polarization and strain, we provide direct experimental proof for the straight DW structure predicted by ab initio calculations as well as the recently proposed theory of diffuse DWs, thus resolving a long-standing discrepancy between experimentally measured and theoretically predicted DW mobilities.
Prediction of Carbohydrate Binding Sites on Protein Surfaces with 3-Dimensional Probability Density Distributions of Interacting Atoms
(2012-07-25)
Tsai, Keng-Chang
;
Jian, Jhih-Wei
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Yang, Ei-Wen
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Hsu, Po-Chiang
;
Peng, Hung-Pin
Non-covalent protein-carbohydrate interactions mediate molecular targeting in many biological processes. Prediction of non-covalent carbohydrate binding sites on protein surfaces not only provides insights into the functions of the query proteins; information on key carbohydrate-binding residues could suggest site-directed mutagenesis experiments, design therapeutics targeting carbohydrate-binding proteins, and provide guidance in engineering protein-carbohydrate interactions. In this work, we show that non-covalent carbohydrate binding sites on protein surfaces can be predicted with relatively high accuracy when the query protein structures are known. The prediction capabilities were based on a novel encoding scheme of the three-dimensional probability density maps describing the distributions of 36 non-covalent interacting atom types around protein surfaces. One machine learning model was trained for each of the 30 protein atom types. The machine learning algorithms predicted tentative carbohydrate binding sites on query proteins by recognizing the characteristic interacting atom distribution patterns specific for carbohydrate binding sites from known protein structures. The prediction results for all protein atom types were integrated into surface patches as tentative carbohydrate binding sites based on normalized prediction confidence level. The prediction capabilities of the predictors were benchmarked by a 10-fold cross validation on 497 non-redundant proteins with known carbohydrate binding sites. The predictors were further tested on an independent test set with 108 proteins. The residue-based Matthews correlation coefficient (MCC) for the independent test was 0.45, with prediction precision and sensitivity (or recall) of 0.45 and 0.49 respectively. In addition, 111 unbound carbohydrate-binding protein structures for which the structures were determined in the absence of the carbohydrate ligands were predicted with the trained predictors. The overall prediction MCC was 0.49. Independent tests on anti-carbohydrate antibodies showed that the carbohydrate antigen binding sites were predicted with comparable accuracy. These results demonstrate that the predictors are among the best in carbohydrate binding site predictions to date.
CARRIER COMPONENT AND FABRICATION METHOD THEREOF
(2012-07-26)
Liu Dean-Mo
;
Chang Chun Yu
;
Chou Fu Hsuan
;
Yen Tin-Yo
The present invention provides a carrier component. The carrier component includes a carrier core body including a dispersive object and a dualistic self-assembly material for encapsulating the dispersive object, wherein the dualistic self-assembly material has an electric charge; and a first shell layer having an electric charge opposite to the electric charge of the dualistic self-assembly material, and coating the carrier core body, and thus avoids inactivation of a medicine, eliminates medicine leakage and reduces medicine releasing. The present invention further provides a method for forming a carrier component.
Encoding of Physics Concepts: Concreteness and Presentation Modality Reflected by Human Brain Dynamics
(2012-07-27)
Lai, Kevin
;
She, Hsiao-Ching
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Chen, Sheng-Chang
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Chou, Wen-Chi
;
Huang, Li-Yu
Previous research into working memory has focused on activations in different brain areas accompanying either different presentation modalities (verbal vs. non-verbal) or concreteness (abstract vs. concrete) of non-science concepts. Less research has been conducted investigating how scientific concepts are learned and further processed in working memory. To bridge this gap, the present study investigated human brain dynamics associated with encoding of physics concepts, taking both presentation modality and concreteness into account. Results of this study revealed greater theta and low-beta synchronization in the anterior cingulate cortex (ACC) during encoding of concrete pictures as compared to the encoding of both high and low imageable words. In visual brain areas, greater theta activity accompanying stimulus onsets was observed for words as compared to pictures while stronger alpha suppression was observed in responses to pictures as compared to words. In general, the EEG oscillation patterns for encoding words of different levels of abstractness were comparable but differed significantly from encoding of pictures. These results provide insights into the effects of modality of presentation on human encoding of scientific concepts and thus might help in developing new ways to better teach scientific concepts in class.
Tunable GHz pulse repetition rate operation in high-power TEM00-mode Nd:YLF lasers at 1047 nm and 1053 nm with self mode locking
(2012-07-30)
Huang, Y. J.
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Tzeng, Y. S.
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Tang, C. Y.
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Huang, Y. P.
;
Chen, Y. F.
We report on a high-power diode-pumped self-mode-locked Nd:YLF laser with the pulse repetition rate up to several GHz. A novel tactic is developed to efficiently select the output polarization state for achieving the stable TEM00-mode self-mode-locked operations at 1053 nm and 1047 nm, respectively. At an incident pump power of 6.93 W and a pulse repetition rate of 2.717 GHz, output powers as high as 2.15 W and 1.35 W are generated for the sigma- and pi-polarization, respectively. We experimentally find that decreasing the separation between the gain medium and the input mirror not only brings in the pulse shortening thanks to the enhanced effect of the spatial hole burning, but also effectively introduces the effect of the spectral filtering to lead the Nd: YLF laser to be in a second harmonic mode-locked status. Consequently, pulse durations as short as 8 ps and 8.5 ps are obtained at 1053 nm and 1047 nm with a pulse repetition rate of 5.434 GHz. (C) 2012 Optical Society of America
Pixel driving structure of displaying three colors of particle display and its displaying colors method
(2012-07-31)
Fan Shih-Kang
;
Chiu Cheng-Pu
;
Hsu Ching-Hsiang
;
Mo Chi-Neng
;
Chiang Mei-Tsao
A pixel driving structure of a particle display displaying three colors and a method for displaying colors thereof are provided. The pixel driving structure includes a first substrate; a first electrode layer disposed on a surface of the first substrate; a second substrate disposed opposite to the first substrate; a second electrode layer on the second substrate; a particle solution disposed between the first electrode layer and the second electrode layer and having a first color solution, a plurality of second color positive particles, and a plurality of third color negative particles; and an alternating/direct power supply connecting with the first and second electrode layers. A method for displaying color includes steps of applying an alternating voltage to display a first color; applying a first direct voltage to display a third color; and applying a second direct voltage to display a second color.
"Dielectrophoretic placement of quasi-zero-, one-, and two-dimensional nanomaterials into nanogap for electrical characterizations"
(2012-08-01)
Lin, Yen-Fu
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Chiu, Shao-Chien
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Wang, Sheng-Tsung
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Fu, Sheng-Kai
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Chen, Chien-Hsiang
"DEP is one of promising techniques for positioning nanomaterials into the desirable location for nanoelectronic applications. In contrast, the lithography technique is commonly used to make ultra-thin conducting wires and narrow gaps but, due to the limit of patterning resolution, it is not feasible to make electrical contacts on ultra-small nanomaterials for a bottom-up device fabrication. Thus, integrating the lithography and dielectrophoresis, a real bottom-up fabrication can be achieved. In this work, the device with the nanogap in between two nanofinger-electrodes is made using electron-beam lithography from top down and the ultra-small nanomaterials, such as colloidal PbSe quantum dots, polyaniline nanofibers, and reduced-graphene-oxide flakes, are placed in the nanogap by DEP from bottom up. The threshold electric field for the DEP placement of PbSe nanocrystals was roughly estimated to be about 8.3 x 104 V/cm under our experimental configuration. After the DEP process, several procedures for reducing contact resistances are attempted and measurements of intrinsic electron transport in versatile nanomaterials are performed. It is experimentally confirmed that electron transport in both PbSe nanocrystal arrays and polyaniline nanofibers agrees well with Prof. Ping Sheng's model of granular metallic conduction. In addition, electron transport in reduced-graphene-oxide flakes follows Mott's 2D variable-range-hopping model. This study illustrates an integration of the electron-beam lithography and the DEP techniques for a precise manipulation of nanomaterials into electronic circuits for characterization of intrinsic properties."
A Cost-Effective Strategy for Road-Side Unit Placement in Vehicular Networks
(2012-08-01)
Wu, Tsung-Jung
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Liao, Wanjiun
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Chang, Chung-Ju
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, we study the Roadside Unit (RSU) placement problem in vehicular networks. We focus on the highway-like scenario in which there may be multiple lanes with exits or intersections along the road. In our model, each vehicle can access RSUs in two ways: 1) direct delivery, which occurs when the vehicle is in the transmission range of the RSUs, and 2) multi-hop relaying, which takes place when the vehicle is out of RSU transmission range. We account for both access patterns in our placement strategy and formulate this placement problem via an integer linear programming model such that the aggregate throughput in the network can be maximized. We also take into account the impact of wireless interference, vehicle population distribution, and vehicle speeds in the formulation. The performance of the proposed placement strategy is evaluated via ns-2 simulations together with VanetMobisim to generate vehicle mobility patterns. The results show that our strategy leads to the best performance as compared with the uniformly distributed placement and the hot spot placement. More importantly, our solution needs the least number of RSUs to achieve the maximal aggregate throughput in the network, indicating that our scheme is indeed a cost effective yet highly efficient placement strategy for vehicular networks.
Simulations of subsonic vortex-shedding flow past a 2D vertical plate in the near-continuum regime by the parallelized DSMC code
(2012-08-01)
Tseng, K. C.
;
Kuo, T. C.
;
Lin, S. C.
;
Su, C. C.
;
Wu, J. S.
A general-purpose Parallel Direct Simulation Monte Carlo Code, named PDSC, is used to simulate near-continuum subsonic flow past a 2D vertical plate for studying the vortex-shedding phenomena. An unsteady time-averaging sampling method and a post-processing procedure called DREAM (DSMC Rapid Ensemble Averaging Method) have also been implemented, reducing the overall computational expense and improving the sampling quality of time-dependent flow problems in the rarefied flow regime. Parametric studies, including the temporal variable time step (TVTS) factor, the number of particles per cell, the domain size, and the Reynolds number, have been conducted, obtaining the Strouhal number and various aerodynamic coefficients of the flow. Results are compared to experimental data in the continuum regime available in the literature, demonstrating the capacity of PDSC and DREAM to simulate near-continuum vortex-shedding problems within acceptable computational time. (C) 2012 Elsevier B.V. All rights reserved.
Optimal two-layer directive microphone array with application in near-field acoustical holography
(2012-08-01)
Bai, Mingsian R.
;
Wang, Chunkai
;
Juan, Shen-Wei
;
機械工程學系
;
Department of Mechanical Engineering
Conventional near-field acoustical holography (NAH) is generally based on the free-field assumption, which can cause errors when interfering sources are present in practical environments. To cope with this problem, previous research suggested a combined pressure-velocity approach for NAH that provides certain advantages to rejection of interferences. This paper revisits this idea in a broader context of optimal array design and examines the feasibility of using unidirectional microphones in each channel of the array such that the robustness of inverse reconstruction is enhanced against interfering sources. As indicated in the simulation, the numerical noise in finite difference estimation of particle velocity can nullify the advantage of the well-conditioned velocity-based reconstruction. In the proposed approach, the characteristics of each array channel consisting of two microphones are tailored by taking into account not only the directivity, but also the robustness against self-noise. An objective function based on directivity index and white noise gain is exploited in a linear quadratic optimization of a two-element end-fire array. The proposed optimal array is validated in conjunction with the equivalent source model (ESM) -based NAH through numerical simulations, with an interfering source positioned behind the array. The results have shown the directive optimal array has yielded improved quality of images in comparison with conventional approaches in the presence of an interfering source and sensor noise. (C) 2012 Acoustical Society of America. [http://dx.doi.org/10.1121/1.4734238]
Generating tri-chaos attractors with three positive Lyapunov exponents in new four order system via linear coupling
(2012-08-01)
Li, Shih-Yu
;
Huang, Sheng-Chieh
;
Yang, Cheng-Hsiung
;
Ge, Zheng-Ming
;
機械工程學系
This paper presents a new hyperchaotic system with three positive Lyapunov exponents (called Tri-Chaos). Via linear coupling, Mathieu, and van der Pol systems are coupled with each other and then become a new four order system-Mathieu-van der Pol autonomous system. As we know, two positive Lyapunov exponents confirm hyperchaotic nature of its dynamics and it means that the system can present more complicated behavior than ordinary chaos. We further generate three positive Lyapunov exponents in a new coupled nonlinear system and anticipate the advanced application in secure communication. Not only a new chaotic system with three Lyapunov exponents is proposed, but also its implementation of an electronic circuit is put into practice in this article. The phase portrait, electronic circuit, power spectrum, Lyapunov exponents, and 2-D and 3-D parameter diagram of tri-chaos with three positive Lyapunov exponents of the new system will be shown in this paper.
交大資訊人
(2012-08)
College of Computer Science
;
資訊學院
[院長的話] P.1 [產學合作] P.2 交大「鑽石計畫」資通實驗室推展產學合作 [國際學術交流] P.3 資訊學院盛邀國際知名學者蒞校交流拓廣國際視野 [人物專訪] P.5 曾煜棋院長-大膽假設、勇於發想，化腐朽為神奇陳志成所長-培養獨立研究精神堅持不懈克服萬難 [資訊系友] P.7 台電董座黃重球：把握學習機會豐富生命內涵資工人永遠的家-「資訊系友會」 [獲獎捷報] P.9 [學生獲獎] P.10 魏綾音、張郡庭同學榮獲 Google 安妮塔博格紀念獎學金 [活動花絮] P.11 100 學年度資公小畢典：帶著資工精神飛往錦繡前程 [院系消息] P.13 資訊學院課程大翻新 101 學年度正式實施發行人 / 曾煜棋院長；顧問 / 莊榮宏副院長
New water-soluble highly selective fluorescent chemosensor for Fe (III) ions and its application to living cell imaging
(2012-08-01)
Liu, Shi-Rong
;
Wu, Shu-Pao
;
應用化學系
;
Department of Applied Chemistry
A new rhodamine-based chemosensor exhibits excellent selectivity for Fe3+ ions over a wide range of tested metal ions Ag+, Al3+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Fe2+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ in an aqueous solution. The binding of Fe3+ to chemosensor 1 produces an absorption band at 564 nm and an emission band at 588 nm because Fe3+-binding induces ring-opening of the spirolactam in 1. The binding ratio of the 1-Fe3+ complexes was determined to be 1:1 according to a Job plot. The association constant (K-a) of Fe3+ binding in chemosensor 1 was 6.9 x 10(3) M-1. The maximum fluorescence enhancement caused by Fe3+ binding in chemosensor 1 occurred at a pH range of 6-7.5. The fluorescence microscopy experiments in this study demonstrated that chemosensor 1 can be used as a fluorescent probe for detecting Fe3+- in living cells. (C) 2012 Elsevier B.V. All rights reserved.