Browsing by Issue Date, starting with "2016-01-25"

Now showing 1 - 20 of 18073

Improvement of light quality by ZrO2 film of chip on glass structure white LED
(2016-01-25)
Lin, Huang-Yu
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Ye, Zhi-Ting
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Lin, Chien-Chung
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Chen, Kuo-Ju
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Tu, Hsien-Hao
A novel combination of blue LED chips, transparent glass substrates and phosphors with PDMS thin film is demonstrated. The flip-chip bonding technology is applied to facilitate this design. The ZrO2 nanoparticles are also doped into the PDMS film to increase light scattering. The resultant luminous efficiency shows an 11% enhancement when compared to the regular COG device. The variation of correlated color temperature of such devices is also reduced to 132K. In addition to these changes, the surface temperature is reduced from 121 degrees C to 104 degrees C due to good thermal dissipation brought by ZrO2 nanoparticles. (C) 2015 Optical Society of America
Spectrally efficient polarization multiplexed direct-detection OFDM system without frequency gap
(2016-01-25)
Wei, Chia-Chien
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Zeng, Wei-Siang
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Lin, Chun-Ting
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光電系統研究所
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Institute of Photonic System
We experimentally demonstrate a spectrally efficient direct-detection orthogonal frequency-division multiplexing (DD-OFDM) system. In addition to polarization-division multiplexing, removing the frequency gap further improves the spectral efficiency of the OFDM system. The frequency gap between a reference carrier and OFDM subcarriers avoids subcarrier-to-subcarrier beating interference (SSBI) in traditional DD-OFDM systems. Without dynamic polarization control, the resulting interference after square-law direct detection in the proposed gap-less system is polarization-dependent and composed of linear inter-carrier interference (ICI) and nonlinear SSBI. Thus, this work proposes an iterative multiple-input multiple-output detection scheme to remove the mixed polarization-dependent interference. Compared to the previous scheme, which only removes ICI, the proposed scheme can further eliminate SSBI to achieve the improvement of similar to 7 dB in signal-to-noise ratio. Without the need for polarization control, we successfully utilize 7-GHz bandwidth to transmit a 39.5-Gbps polarization multiplexed OFDM signal over 100 km. (C) 2016 Optical Society of America
Rear interface engineering of hybrid organic-silicon nanowire solar cells via blade coating
(2016-01-25)
Lai, Yi-Chun
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Chang, Yu-Fan
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Tsai, Pei-Ting
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Chang, Jan-Kai
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Tseng, Wei-Hsuan
In this work, we investigate blade-coated organic interlayers at the rear surface of hybrid organic-silicon photovoltaics based on two small molecules: Tris(8-hydroxyquinolinato) aluminium (Alq(3)) and 1,3-bis(2-(4-tert- butylphenyl)-1,3,4-oxadiazol-5-yl) benzene (OXD-7). In particular, soluble Alq3 resulting in a uniform thin film with a root-mean-square roughness < 0.2nm is demonstrated for the first time. Both devices with the Alq3 and OXD-7 interlayers show notable enhancement in the open-circuit voltage and fill-factor, leading to a net efficiency increase by over 2% from the reference, up to 11.8% and 12.5% respectively. The capacitance-voltage characteristics confirm the role of the small-molecule interlayers resembling a thin interfacial oxide layer for the Al-Si Schottky barrier to enhance the built-in potential and facilitate charge transport. Moreover, the Alq3 interlayer in optimized devices exhibits isolated phases with a large surface roughness, in contrast to the OXD-7 which forms a continuous uniform thin film. The distinct morphological differences between the two interlayers further suggest different enhancement mechanisms and hence offer versatile functionalities to the advent of hybrid organic-silicon photovoltaics. (C)2016 Optical Society of America
Automatic and objective oral cancer diagnosis by Raman spectroscopic detection of keratin with multivariate curve resolution analysis
(2016-01-25)
Chen, Po-Hsiung
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Shimada, Rintaro
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Yabumoto, Sohshi
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Okajima, Hajime
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Ando, Masahiro
We have developed an automatic and objective method for detecting human oral squamous cell carcinoma (OSCC) tissues with Raman microspectroscopy. We measure 196 independent Raman spectra from 196 different points of one oral tissue sample and globally analyze these spectra using a Multivariate Curve Resolution (MCR) analysis. Discrimination of OSCC tissues is automatically and objectively made by spectral matching comparison of the MCR decomposed Raman spectra and the standard Raman spectrum of keratin, a well-established molecular marker of OSCC. We use a total of 24 tissue samples, 10 OSCC and 10 normal tissues from the same 10 patients, 3 OSCC and 1 normal tissues from different patients. Following the newly developed protocol presented here, we have been able to detect OSCC tissues with 77 to 92% sensitivity (depending on how to define positivity) and 100% specificity. The present approach lends itself to a reliable clinical diagnosis of OSCC substantiated by the "molecular fingerprint" of keratin.
Direct Synthesis and Practical Bandgap Estimation of Multilayer Arsenene Nanoribbons
(2016-01-26)
Tsai, Hsu-Sheng
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Wang, Sheng-Wen
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Hsiao, Ching-Hung
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Chen, Chia-Wei
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Ouyang, Hao
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
;
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