Browsing by Issue Date, starting with "2016-01-27"

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Single-crystalline aluminum film for ultraviolet plasmonic nanolasers
(2016-01-27)
Chou, Bo-Tsun
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Chou, Yu-Hsun
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Wu, Yen-Mo
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Chung, Yi-Cheng
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Hsueh, Wei-Jen
Significant advances have been made in the development of plasmonic devices in the past decade. Plasmonic nanolasers, which display interesting properties, have come to play an important role in biomedicine, chemical sensors, information technology, and optical integrated circuits. However, nanoscale plasmonic devices, particularly those operating in the ultraviolet regime, are extremely sensitive to the metal and interface quality. Thus, these factors have a significant bearing on the development of ultraviolet plasmonic devices. Here, by addressing these material-related issues, we demonstrate a low-threshold, high-characteristic-temperature metal-oxide-semiconductor ZnO nanolaser that operates at room temperature. The template for the ZnO nanowires consists of a flat single-crystalline Al film grown by molecular beam epitaxy and an ultrasmooth Al2O3 spacer layer synthesized by atomic layer deposition. By effectively reducing the surface plasmon scattering and metal intrinsic absorption losses, the high-quality metal film and the sharp interfaces formed between the layers boost the device performance. This work should pave the way for the use of ultraviolet plasmonic nanolasers and related devices in a wider range of applications.
Control of the Metal-Insulator Transition at Complex Oxide Heterointerfaces through Visible Light
(2016-01-27)
Lin, Jheng-Cyuan
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Vu Thanh Tra
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Tsai, Dung-Sheng
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Lin, Tai-Te
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Huang, Po-Cheng
The coupling of the localized surface plasmon resonance of Au nanoparticles is utilized to deliver a visible-light stimulus to control conduction at the LaAlO3/SrTiO3 interface. A giant photoresponse and the controllable metal-insulator transition are characterized at this heterointerface. This study paves a new route to optical control of the functionality at the heterointerfaces.
Intrinsic coordination for revealing local structural changes in protein folding-unfolding
(2016-01-28)
Shiu, Ying-Jen
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Hayashi, Michitoshi
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Shih, Orion
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Su, Charlene
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Tsai, Min-Yeh
With a deformed object of a rigid rod inside, the local dislocations may be tracked relatively easily with respect to the internal rigid rod. We apply this concept on protein folding-unfolding to track the internal structural changes of an unfolded protein in solution. Proposed here is a protein internal coordination based on the major axis X of an ellipsoidal protein and the stable intrinsic transition dipole moment mu of the protein during unfolding. In this methodology, small-angle X-ray scattering (SAXS) is used to provide the protein global morphologies in the native and unfolded states. Furthermore, time-resolved fluorescence anisotropy (TRFA) provides the relative orientation between X and mu of Trp59 of the model protein cytochrome c. Hence observed in the protein unfolding with denaturants, acid, urea, or GuHCl, is the elongation of the native protein conformation along a reoriented protein major axis; accompanied are the different extents of relocations of the terminal a helices and loop structures of the protein in the corresponding unfolding.
Measurement of heart rate variability using off-the-shelf smart phones
(2016-01-29)
Huang, Ren-You
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Dung, Lan-Rong
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電機工程學系
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電控工程研究所
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Department of Electrical and Computer Engineering
Background: The cardiac parameters, such as heart rate (HR) and heart rate variability (HRV), are very important physiological data for daily healthcare. Recently, the camera-based photoplethysmography techniques have been proposed for HR measurement. These techniques allow us to estimate the HR contactlessly with low-cost camera. However, the previous works showed limit success for estimating HRV because the R-R intervals, the primary data for HRV calculation, are sensitive to noise and artifacts. Methods: This paper proposed a non-contact method to extract the blood volume pulse signal using a chrominance-based method followed by a proposed CWT-based denoising technique. The R-R intervals can then be obtained by finding the peaks in the denoised signal. In this paper, we taped 12 video clips using the frontal camera of a smart phone with different scenarios to make comparisons among our method and the other alternatives using the absolute errors between the estimated HRV metrics and the ones obtained by an ECG-accurate chest band. Results: As shown in experiments, our algorithm can greatly reduce absolute errors of HRV metrics comparing with the related works using RGB color signals. The mean of absolute errors of HRV metrics from our method is only 3.53 ms for the static-subject video clips. Conclusions: The proposed camera-based method is able to produce reliable HRV metrics which are close to the ones measured by contact devices under different conditions. Thus, our method can be used for remote health monitoring in a convenient and comfortable way.
直列接続式の高電子移動度トランジスターデバイス及びその製造方法
(2016-01-29)
張翼
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許恒通
A computational study on the energetics and mechanisms for the dissociative adsorption of SiHx(x=1-4) on W(111) surface
(2016-01-30)
Lin, Y. H.
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Raghunath, P.
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Lin, M. C.
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應用化學系
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Department of Applied Chemistry
The adsorption and dissociation mechanisms of SiHx(x = 1-4) species on W(111) surface have been investigated by using the periodic density functional theory with the projector-augmented wave approach. The adsorption of all the species on four surface sites: top (T), bridge (B), shallow (S), and deep (D) sites have been analyzed. For SiH4 on a top site, T-SiH4(a), it is more stable with an adsorption energy of 2.6 kcal/mol. For SiH3, the 3-fold shallow site is most favorable with adsorption energy of 46.0 kcal/mol. For SiH2, its adsorption on a bridge site is most stable with 73.0 kcal/mol binding energy, whereas for SiH and Si the most stable adsorption configurations are on 3-fold deep sites with very high adsorption energies, 111.8 and 134.7 kcal/mol, respectively. The potential energy surfaces for the dissociative adsorption of all SiH species on the W(111) surface have been constructed using the CINEB method. The barriers for H-atom migration from SiHx(a) to its neighboring W atoms, preferentially on B-sites, were predicted to be 0.4, 1.0, 4.5 and, 8.0 kcal/mol, respectively, for x= 4, 3, 2, and 1, respectively. The adsorption energy of the H atom on a bridge site on the clean W(1 1 1) surface was predicted to be 65.9 kcal/mol, which was found to be slightly affected by the co-adsorption of SiHx-1 within +/- 1 kcal/mol. (C) 2015 Elsevier B.V. All rights reserved.
Making and animating transformable 3D models
(2016-02-01)
Huang, Yi-Jheng
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Chan, Shu-Yuan
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Lin, Wen-Chieh
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Chuang, Shan-Yu
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資訊工程學系
Transformable models are 3D models whose shapes can be changed by rotating or translating their component parts. They have a variety of applications in our daily lives, being used in film props and sets, robots, furniture, tools, and toys. Successful transformable models, however, are challenging to create. In this paper, we present a new approach to designing and animating a transformable model, in which a source model is optimally segmented based on a target model and skeleton provided by users, and the motion of transformation is mapped from the source to target models. Our experimental results indicate that our system can transform a 3D model plausibly. (C) 2015 Elsevier Ltd. All rights reserved.
Blade coating of Tris(8-hydroxyquinolinato)aluminum as the electron-transport layer for all-solution blue fluorescent organic light-emitting diodes
(2016-02-01)
Chang, Yu-Fan
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Meng, Hsin-Fei
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Fan, Gang-Lun
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Wong, Ken-Tsung
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Zan, Hsiao-Wen
Organic light-emitting diodes (OLEDs) with a low driving voltage and efficient blue fluorescence were fabricated through blade coating. Tris(8-hydroxyquinolinato)aluminum (Alq(3)) is a relatively stable electron-transporting material commonly used in evaporation. However, depositing Alq(3) through a solution process is difficult because of its extremely low solubility organic solvents, a result of its symmetrical molecular structure. In this study, Alq(3) was successfully deposited through blade coating at a very low concentration below 0.1wt%. The OLEDs contained co-dopants BUBD-1 and p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-Ph), and a high-band-gap host 2-methyl-9,10-bis(naphthalen-2-yl) anthracene (MADN) as the emission layer with the following structure: ITO/PEDOT:PSS (40 nm)/VB-FNPD (30 nm)/MADN:2% BUBD-1:1% DSA-Ph (50 nm)/TPBI (30 nm)/LiF (0.8 nm)/Al (100 nm)or ITO/PEDOT:PSS (40 nm)/VB-FNPD (30 nm)/MADN:3% BUBD-1 (50 nm)tris(8-hydroxyquinolinato)aluminum (Alq(3); 10 nm)/LiF (0.8 nm)/Al (100 nm). 2,7-disubstituted fluorene-based triaryldiamine(VB-FNPD)is the cross-linking transporting material. The device exhibited a peak current efficiency of 5.67 cd/A for Alq(3) and 5.76 cd/A for TPBI. The device with Alq(3) has operated lifetime seven times higher than the device with TPBI. (C) 2015 Elsevier B.V. All rights reserved.
Traffic situation visualization based on video composition
(2016-02-01)
Hsieh, Cheng-You
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Wang, Yu-Shuen
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交大名義發表
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National Chiao Tung University
Vehicle detectors (VDs) are usually distributed in a road network to detect macroscopic traffic situations. These detectors provide global information such as vehicle flows, average speed, and road occupancy. Given that the collected statistic data are difficult for citizens to interpret, we visualize the data by providing users with realistic traffic videos. To achieve this aim, our system collects the surveillance videos and VD data that represent the traffic situation of a position. It then builds the connection between these two types of data. Considering the distribution of VDs is much denser than that of surveillance cameras, for those road segments with a VD but without a surveillance camera, one can utilize our system to synthesize videos for visually depicting the traffic situations over there. That is, we estimate vehicle flows from a video and apply the regression model to build the mapping between the flows and VD data. After that, given by a VD dataset, our system retrieves videos that match the VD data and seamlessly composes them to synthesize a traffic video. The evaluations and the experimental results demonstrate the feasibility of our system. (C) 2015 Elsevier Ltd. All rights reserved.
Optical Trapping Dynamics of a Single Polystyrene Sphere: Continuous Wave versus Femtosecond Lasers
(2016-02)
Liu, Tsung-Han
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Chiang, Wei-Yi
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Usman, Anwar
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Masuhara, Hiroshi
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應用化學系
Understanding of optical trapping dynamics of a single particle in the trapping site is important to develop its optical manipulation for molecular assembly and chemical application. For micrometer-sized Mie particles, similar trapping efficiency of the conventional continuous wave (cw) laser or high-repetition-rate femtosecond (fs) laser pulse train has been established [Dholakia et al., Opt. Express 2010, 18, 7554-7568], in contrast to higher efficiency of the laser pulses to trap dielectric Rayleigh particles. To further explore and clarify the switching phenomena of optical trapping efficiency with cw laser and fs laser pulse and to elucidate its nature, we study the immobilization dynamics of a single polystyrene sphere with 500 nm in diameter (which is comparable to focal beam size) in shallow potential well. By observing trapping events and immobilization time of the particle with a size in Lorenz-Mie regime, distinct from well-known Rayleigh particle and ray optics approximations, we found that immobilization time is only linearly related to the incident laser power <= 40 mW, and at higher laser powers cw laser is more efficient than fs laser pulses to immobilize the particle. This finding means that the dynamics of the particle in this size region is still affected by the strong transient force fields induced by high-repetition-rate ultrashort pulse train as usually observed for Rayleigh particles. This may provide an understanding that the dynamics of the target particle in the trapping site is size- and laser mode-dependent.
Amplitude and Phase Modulation of UWB Monocycle Pulses on a Silicon Photonic Chip
(2016-02-01)
Xu, Ke
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Wu, Xinru
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Sung, Jiun-Yu
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Cheng, Zhenzhou
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Chow, Chi Wai
We demonstrate both the amplitude and bi-phase modulation of ultrawideband (UWB) monocycle pulses using silicon microring modulator. The integrated silicon ring modulator generates the monocycle pulse train and modulates it simultaneously. By applying different driving voltages, the amplitude and phase-modulated UWB signal with a data rate of 2.5 Gb/s are achieved. The ring modulator can be thermally tuned for a free spectral range with a similar to 50-mW power consumption.
Distributed Emergency Guiding with Evacuation Time Optimization Based on Wireless Sensor Networks
(2016-02)
Chen, Lien-Wu
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Cheng, Jen-Hsiang
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Tseng, Yu-Chee
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資訊工程學系
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Department of Computer Science
This paper proposes a load-balancing framework for distributed emergency guiding based on wireless sensor networks. A load-balancing guiding scheme is designed and an analytical model is derived to reduce the total evacuation time of people indoors. The guiding scheme can provide the fastest path for people to reach an exit according to the evacuation time estimated using the analytical model. Based on thorough research, this is the first distributed solution in which corridor capacity and length, exit capacity, and the concurrent movement and distribution of people are considered in estimating the evacuation time and planning escape paths. Using the proposed framework, congestion in corridors and at exits can be eased to substantially reduce the total evacuation time. Analytical and simulation results show that this approach outperforms existing schemes and can prevent people from following local-optimal guiding directions that increase the evacuation time. A prototype called the Load-balancing Emergency Guiding System (LEGS) is implemented; this system can be used to compare the evacuation times and guiding directions provided by existing schemes and the proposed scheme for various distributions of people.
Facile Fabrication of a Sensor with a Bifunctional Interface for Logic Analysis of the New Delhi Metallo-beta-Lactamase (NDM)-Coding Gene
(2016-02)
Kuo, Tsui-Ming
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Shen, Mo-Yuan
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Huang, Shih-Ying
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Li, Yaw-Kuen
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Chuang, Min-Chieh
Surface functionalization has attracted considerable interest from researchers because of its capability for facilitating the interface communication between an energy transducer and a biological system. We report newly synthesized N-(4-aminobenzoyl)-N\'-(4-maleimidobenzoyl)1,2-ethylenediamine (AME) to promote the modification of the surface with thiolated DNA and 3-((4-aminophenyl)dimethylammonio)propane-1-sulfonate (APSB) for the facile formation of a bifunctional interface forming an antifouling surface. Through the formation of diazonium ion, electrochemically reductive deposition of the two arylamines can fabricate simultaneously and effectively a bifunctional surface on a gold electrode and install a DNA probe to form a sensor; the sensor was applied to detect three genetic fragments of the New Delhi Metallo-beta-Lactamase (NDM)-coding gene. Effects of the diazotization and the conditions of electrochemical deposition upon the sensing signals were investigated in connection with enumerating the accessible maleimide groups and assessing the diffusion resistance of the electroactive indicator. The detection limit given by the diazonium-constructed system was improved to attain the level of 54 pM, an advance over a conventional self assembled monolayer.
Room temperature fabrication of titanium nitride thin films as plasmonic materials by high-power impulse magnetron sputtering
(2016-02-01)
Yang, Zih-Ying
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Chen, Yi-Hsun
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Liao, Bo-Huei
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Chen, Kuo-Ping
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照明與能源光電研究所
High-power impulse magnetron sputtering (HiPIMS) was used to deposit titanium nitride (TiN) thin films with high electron density as alternative plasmonic materials. TiN thin films with thicknesses of 20-40 nm were deposited with different average sputtering powers, and exhibited metallic-and dielectric-like optical properties. When the sputtering power was increased from 80 W to 300 W, denser polycrystalline TiN thin films were obtained at room temperature (RT) with a conductivity 25 times that of the low-sputtering-power film. With sufficient average power (>= 180 W), the films exhibited metallic-like optical properties, and a conductivity of >10(5) S/m. By using HiPIMS deposition, good-quality metallic-like TiN thin films could be fabricated at RT without heating the substrate. (C) 2016 Optical Society of America
Technology Evaluation and Selection of 3DIC Integration Using a Three-Stage Fuzzy MCDM
(2016-02-01)
Lee, Yen-Chun
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Chou, C. James
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科技管理研究所
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交大研究總中心
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Institute of Management of Technology
Reliability study of high-k La2O3/HfO2 and HfO2/La2O3 stacking layers on n-In0.53Ga0.47As metal-oxide-semiconductor capacitor
(2016-02)
Chu, Chung-Ming
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Lin, Yueh-Chin
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Lee, Wei-I
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Dee, Chang Fu
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Wong, Yuen-Yee
This study investigates the time-dependent dielectric breakdown (TDDB) characteristics of La2O3/HfO2 and HfO2/La2O3 stacking layers on an n-In0.53Ga0.47As metal-oxide-semiconductor capacitor. Both designs improved the reliability compared with a single layer of HfO2. The TDDB followed the thermochemical E model. The current transportation mechanism changed from thermionic emission to Frenkel-Poole emission because of the traps creation under voltage stress. Both designs resulted in similar lifespans and voltage accelerating factors. However, the La2O3/HfO2 design had a longer lifespan because of the lower interface trap density and insertion of the HfO2 diffusion barrier layer between La2O3 and n-In0.53Ga0.47As. The oxide stacks exhibited excellent reliability and achieved a lifespan of 28.4 years. (C) 2016 The Japan Society of Applied Physics
Traffic diversity and code coverage: a preliminary analysis
(2016-02-01)
Lin, Ying-Dar
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Lai, Yuan-Cheng
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Lu, Chun-Nan
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Hung, Jui-Tsun
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Shao, Chun-Pin
It is generally assumed that using more diverse traffic to test network devices could achieve larger code coverage. However, how to describe the diversity of traffic traces and the relationship between the traffic diversity and code coverage is still an issue. In this paper, the traffic diversity is defined using the number of packets and the size of the subnets involved, and traces having various diversity are used to evaluate the corresponding code coverage for the programs in a network device. Experiment results show that more number of packets or larger size of network segments can generate larger diversity indices and thus larger code coverage. For Snort, as the number of packets increases from 1 to 10,000,000, representative diversity index and the code coverage can increase from 0 to 0.95 on the basis of Simpson\'s index and from 19.1% to 32.2%, respectively. As the size of network segments increases, representative diversity index and the code coverage can increase from 0.41 to 0.82 and from 28.2% to 32.2%, respectively. Similar results can be obtained in the case of Linux kernel. If the mappings among different diversity indices and the corresponding code coverage can be built beforehand, the quality of the tests can improved. Copyright (c) 2014 John Wiley & Sons, Ltd.
Brain tissue oxygen evaluation by wireless near-infrared spectroscopy
(2016-02-01)
Wang, Che-Chuan
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Kuo, Jinn-Rung
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Chen, Yu-Chih
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Chio, Chung-Ching
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Wang, Jhi-Joung
Background: Monitoring the partial pressure of oxygen in brain tissue (PbtO(2)) is an important tool for traumatic brain injury (TBI) but is invasive and inconvenient for real time monitoring. Near-infrared spectroscopy (NIRS), which can monitor hemoglobin parameters in the brain tissue, has been used widely as a noninvasive tool for assessing cerebral ischemia and hypoxia. Therefore, it may have the potential as a noninvasive tool for estimating the change of PbtO(2). In this study, a novel wireless NIRS system was designed to monitor hemoglobin parameters of rat brains under different impact strengths and was used to estimate the change of PbtO(2) noninvasively in TBI. Materials and methods: The proposed wireless NIRS system and a PbtO(2) monitoring system were used to monitor the oxygenation of rat brains under different impact strengths. Rats were randomly assigned to four different impact strength groups (sham, 1.6 atm, 2.0 atm, and 2.4 atm; n = 6 per group), and the relationships of concentration changes in oxyhemoglobin (HbO(2)), deoxyhemoglobin (HbR), and total hemoglobin (HbT), and PbtO(2) during and after TBI with different impact strengths were investigated. Triphenyltetrazolium chloride (TTC) staining was also used to evaluate infarction volume. Results: Concentration changes in HbO(2), HbR, and HbT dropped immediately after the impact, increased gradually, and then became stable. Changes in PbtO(2) had a similar tendency with the hemoglobin parameters. There was significant correlation between changes in PbtO(2) and HbO(2) (correlation = 0.76) but not with changes in HbR (correlation = 0.06). In triphenyltetrazolium chloride staining, the infarction volume was highly but negatively associated with oxygen-related parameters like PbtO(2) and HbO(2). Conclusions: Changes in HbO(2) under TBI was highly and positively correlated with changes in PbtO(2). By using the relative changes in HbO(2) as a reference parameter, the proposed
Incremental mining of temporal patterns in interval-based database
(2016-02-01)
Hui, Lin
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Chen, Yi-Cheng
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Weng, Julia Tzu-Ya
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Lee, Suh-Yin
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資訊工程學系
In several real-life applications, sequence databases, in general, are updated incrementally with time. Some discovered sequential patterns may be invalidated and some new ones may be introduced by the evolution of the database. When a small set of sequences grow, or when some new sequences are added into the database, re-mining sequential patterns from scratch each time is usually inefficient and thus not feasible. Although there have been several recent studies on the maintenance of sequential patterns in an incremental manner, these works only consider the patterns extracted from time point-based data. Few research efforts have been elaborated on maintaining time interval-based sequential patterns, also called temporal patterns, where each datum persists for a period of time. In this paper, an efficient algorithm, Inc_TPMiner (Incremental Temporal Pattern Miner) is developed to incrementally discover temporal patterns from interval-based data. Moreover, the algorithm employs some optimization techniques to reduce the search space effectively. The experimental results on both synthetic and real datasets indicate that Inc_TPMiner significantly outperforms re-mining with static algorithms in execution time and possesses graceful scalability. Furthermore, we also apply Inc_TPMiner on a real dataset to show the practicability of incremental mining of temporal patterns.
Laminar Flame Speeds of Gasoline Surrogates Measured with the Flat Flame Method
(2016-02)
Liao, Y-H.
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Roberts, W. L.
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機械工程學系
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Department of Mechanical Engineering
The adiabatic, laminar flame speeds of gasoline surrogates at atmospheric pressure over a range of equivalence ratios of Phi. = 0.8-1.3 and unburned gas temperatures of 298-400 K are measured with the flat flame method, Which produces a one-dimensional flat flame free of stretch. Surrogates used in the current work are the primary reference fuels (PRFs, mixtures of n-heptane and isooctane), the toluene reference fuels (TRFs; mixtures of toluene and PRFs), and the ethanol reference fuels (ERFs, mixtures of ethanol and PRFs). In general, there is good agreement between the present work and the literature data for single-component fuel and PRF mixtures. Surrogates of TRF mixtures are found to exhibit comparable flame speeds to a real gasoline, while there is discrepancy observed between isooctane and gasoline. Moreover, the laminar flame speeds of TRF mixtures with similar fractions of n-heptane are found to be insensitive to the quantity of toluene in the mixture. Mixtures of ERFs exhibit comparable flame speeds to those of TRF with similar mole fractions, of n-heptane and isooctane.