Browsing by Issue Date, starting with "2019-02-25"

Now showing 1 - 20 of 8133

《逐步東行》，說些關於家鄉的「東西」。
(國立交通大學傳播與科技學系, 2019-02-25)
Hsien Chuang
《逐步東行》--一本竹東的在地刊物中，編輯群是跌破眾人眼鏡、來自竹東國中美術班的幾位學生。從背著相機記錄竹東在地風景、採訪店家，到刊物中細緻的插畫和清新的文字，每期《逐東》都是學生們花了將近八個月的心血，從甄選、學習相關課程、到交稿、退稿、再改稿，才堆砌出這本在地刊物獨有的溫度。
Sunny-Side-Up Egg-Shaped Structures: Surface Modification To Form Anisotropic Polymer Particles Driven by the Plateau-Rayleigh Instability as Fluorescence Manipulation Platforms
(2019-02-26)
Chiu, Yu-Jing
;
Liu, Chih-Ting
;
Weng, Chang-Ching
;
Chiu, Tang-Yao
;
Li, Jia-Wei
The Plateau-Rayleigh instability is a phenomenon driven by the reduction of the surface energies, in which a liquid cylinder transforms to a series of droplets with distinct spacing. This instability phenomenon is also applied broadly for the transformation of cylindrical materials to spherical particles in homogeneous environments. The demonstration of the instability in heterogeneous environments, however, has been less studied. Here, we study the Plateau-Rayleigh instability of electrospun polystyrene (PS)/poly(methyl methacrylate) (PMMA) core-shell fibers annealed on n-octadecyl-trichlorosilane (ODTS)-modified glass substrates with toluene vapors. After the annealing procedures, the PS/PMMA core-shell fibers transform to anisotropic sunny-side-up egg-shaped polymer structures, driven by the reduction of the total surface and interfacial energies. Quantitative analyses are performed on the sizes of the structures. Fluorescent fibers are also prepared by electrospinning and annealed on the ODTS-modified substrates, demonstrating the potential application as fluorescence manipulation platforms.
Enhanced photoelectrochemical hydrogen generation in neutral electrolyte using non-vacuum processed CIGS photocathodes with an earth-abundant cobalt sulfide catalyst
(2019-02-28)
Wang, Mingqing
;
Chang, Yung-Shan
;
Tsao, Chun-Wen
;
Fang, Mei-Jing
;
Hsu, Yung-Jung
This work reports the novelty of using eco-friendly and cost-effective non-vacuum Electrostatic Spray-Assisted Vapour Deposited Cu(In, Ga) SSe (CIGS) thin films as photocathodes, combined with the earth abundant cobalt sulfide (Co-S) as a catalyst to accelerate the kinetics of photogenerated electron transfer and hydrogen generation for photoelectrochemical water splitting. CdS and ZnO layers were subsequently deposited on top of the selenised CIGS films to increase the charge separation and lower the charge recombination for the photocathodes. In order to improve the lifetime and scalability of the CIGS photocathode and the other cell components, a photoelectrochemical test was conducted in a neutral electrolyte of 0.5 M Na2SO4 under simulated sunlight (AM 1.5G). Both the photocurrent densities and the onset potentials of the photocathodes were significantly improved by the electro-deposition of the low cost and earth-abundant Co-S catalyst, with a photocurrent density as high as 19.1 mA cm(-2) at -0.34 V vs. reversible hydrogen electrode (RHE), comparable with and even higher than that of the control photocathode using rare and precious Pt as a catalyst.
RcsB regulation of the YfdX-mediated acid stress response in Klebsiella pneumoniae CG43S3
(2019-02-28)
Liu, Chia-Jui
;
Lin, Ching-Ting
;
Chiang, Jo-Di
;
Lin, Chen-Yi
;
Tay, Yen-Xi
In Klebsiella pneumoniae CG43S3, deletion of the response regulator gene rcsB reduced the capsular polysaccharide amount and survival on exposure to acid stress. A comparison of the pH 4.4-induced proteomes between CG43S3 and CG43S3.rcsB revealed numerous differentially expressed proteins and one of them, YfdX, which has recently been reported as a periplasmic protein, was absent in CG43S3.rcsB. Acid survival analysis was then conducted to determine its role in the acid stress response. Deletion of yfdX increased the sensitivity of K. pneumoniae CG43S3 to a pH of 2.5, and transforming the mutant with a plasmid carrying yfdX restored the acid resistance (AR) levels. In addition, the effect of yfdX deletion was cross-complemented by the expression of the periplasmic chaperone HdeA. Furthermore, the purified recombinant protein YfdX reduced the acid-induced protein aggregation, suggesting that YfdX as well as HdeA functions as a chaperone. The following promoter activity measurement revealed that rcsB deletion reduced the expression of yfdX after the bacteria were subjected to pH 4.4 adaptation. Western blot analysis also revealed that YfdX production was inhibited by rcsB deletion and only the plasmid expressing RcsB or the nonphosphorylated form of RcsB, RcsBD56A, could restore the YfdX production, and the RcsB-mediated complementation was no longer observed when the sensor kinase RcsD gene was deleted. In conclusion, this is the first study demonstrating that YfdX may be involved in the acid stress response as a periplasmic chaperone and that RcsB positively regulates the acid stress response partly through activation of yfdX expression. Moreover, the phosphorylation status of RcsB may affect the YfdX expression under acidic conditions.
A curvature-tunable random laser
(2019-02-28)
Lee, Ya-Ju
;
Yeh, Ting-Wei
;
Yang, Zu-Po
;
Yao, Yung-Chi
;
Chang, Chen-Yu
The application of random lasers has been restricted due to the absence of a well-defined resonant cavity, as the lasing action mainly depends on multiple light scattering induced by intrinsic disorders of the laser medium to establish the required optical feedback that hence increases the difficulty in efficiently tuning and modulating random lasing emissions. This study investigated whether the transport mean free path of emitted photons within disordered scatterers composed of ZnO nanowires is tunable by a curvature bending applied to the flexible polyethylene terephthalate (PET) substrate underneath, thereby creating a unique light source that can be operated above and below the lasing threshold for desirable spectral emissions. For the first time, the developed curvature-tunable random laser is implemented for in vivo biological imaging with much lower speckle noise compared to the non-lasing situation through simple mechanical bending, which is of great potential for studying the fast-moving physiological phenomenon such as blood flow patterns in mouse ear skin. It is expected that the experimental demonstration of the curvature-tunable random laser can provide a new route to develop disorder-based optoelectronic devices.
Bromine-Radical-Mediated Site-Selective Allylation of C(sp(3))-H Bonds
(2019-03-01)
Ueda, Mitsuhiro
;
Maeda, Ayami
;
Hamaoka, Kanako
;
Sasano, Mika
;
Fukuyama, Takahide
The C(sp(3))-H allylation of alkanes is investigated by using allyl bromides under radical reaction conditions. In many cases, methine C-H allylation preceded methylene and methyl C-H allylation with complete or a high degree of site selectivity. The C-H allylation of allylic compounds, such as allylbenzene, gives 1,5-dienes with the S(H)2' reactions of the allyl radicals occurring at the less hindered carbon.
Hexanoyl chitosan/ENR25 blend polymer electrolyte system for electrical double layer capacitor
(2019-03-01)
Winie, Tan
;
Jamal, Asheila
;
Saaid, Farish Irfal
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
Single salt polymer electrolytes based on hexanoyl chitosan-ENR25 were prepared by employing LiN (CF3SO2)(2) or LiCF3SO3 as the doping salt. Elastic property of hexanoyl chitosan was enhanced with the incorporation of ENR25. DSC studies revealed immiscibility of hexanoyl chitosan and ENR25, and dissolution of salt was favored in ENR25 phase. Conductivity enhancement was observed in the blends as compared with the neat hexanoyl chitosan. The maximum conductivities achieved for LiCF3SO3- and LiN (CF3SO2)(2)-comprising electrolyte systems were 1.6 x 10(-8) and 5.0 x 10(-7) S cm(-1), respectively. Deconvolution of spectra bands in the v(as) (SO2-) mode of LiN (CF3SO2)(2) and v(s) (SO3-) mode of LiCF3SO3 has been carried out to estimate the relative percentage of free ions and associated ions. The findings were in good agreement with conductivity results. Electrical double layer capacitor (EDLC) was fabricated with hexanoyl chitosan/ENR25 (90:10)-LiN (CF3SO2)(2)-EmImTFSI electrolyte and activated carbon-based electrodes. The conductivity and electrochemical stability window of hexanoyl chitosan/ENR25-LiN (CF3SO2)(2)-EmImTFSI were similar to 10(-6) S cm(-1) and 2.7 V, respectively. The performance of the EDLC was analyzed by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). From GCD, the specific capacitance of EDLC was 58.0 F g(-1) at 0.6 mA cm(-2). The specific capacitance was found to decrease with increasing current density.
A trading decision support model to maximize the sustainability of a self-financed guaranteed farmgate price program
(2019-03-01)
Chen, Wen-Chih
;
Wu, Cheng-Hung
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
We study a non-government organization (NGO) program that supports the household livelihood of small farmers by committing to purchase a fixed quantity at a guaranteed farmgate price of a storable agri-product under price fluctuation. Since the World Trade Organization (WTO) disciplines its members to limit and reduce domestic support for the agriculture, storing and trading (selling) the product on the spot market at a favorable price generates revenue to cover the cost of the program. The objective of this study is to develop a stochastic dynamic trading decision model that maximizes the sustainability of the NGO's supporting program, measured as the survival probability, i.e. the probability that the program can continue operating after a predetermined period of time. The results of a numerical study, based on the tilapia aquaculture in Taiwan, show that our model yields higher survival probability (after 4 years) than the profit-maximization policy by close to 10% in average. Moreover, the trading decision optimization is particularly suitable for market environments with high price fluctuation, i.e. the most challenging circumstances for small farmers.
Sheaf lines of Yang-Mills instanton sheaves
(2019-03-01)
Lai, Sheng-Hong
;
Lee, Jen-Chi
;
Tsai, I-Hsun
;
電子物理學系
;
Department of Electrophysics
We calculate a sheaf line in CP3 which is the real line supporting sheaf points on CP3 of SL(2, C) Yang-Mills (YM) instanton (or SU(2) complex YM instanton) sheaves for some given ADHM data we obtained previously. We found that this sheaf line is indeed a special jumping line over S-4 spacetime. In addition, we calculate the singularity structure of the connection A and the field strength F at the corresponding singular point on S-4 of this sheaf line. We found that the order of singularity at the singular point on S-4 associated with the sheaf line in CP3 is higher than those of other singular points associated with normal jumping lines. We conjecture that this is a general feature for sheaf lines among jumping lines.
Design Automation for Dilution of a Fluid Using Programmable Microfluidic Device-Based Biochips
(2019-03-01)
Gupta, Ankur
;
Huang, Juinn-Dar
;
Yamashita, Shigeru
;
Roy, Sudip
;
電子工程學系及電子研究所
Microfluidic lab-on-a-chip has emerged as a new technology for implementing biochemical protocols on small-sized portable devices targeting low-cost medical diagnostics. Among various efforts of fabrication of such chips, a relatively new technology is a programmable microfluidic device (PMD) for implementation of flow-based lab-on-a-chip. A PMD chip is suitable for automation due to its symmetric nature. In order to implement a bioprotocol on such a reconfigurable device, it is crucial to automate a sample preparation on-chip as well. In this article, we propose a dilution PMD algorithm (namely DPMD) and its architectural mapping scheme (namely generalized architectural mapping algorithm (GAMA)) for addressing fluidic cells of such a device to perform dilution of a reagent fluid on-chip. We used an optimization function that first minimizes the number of mixing steps and then reduces the waste generation and further reagent requirement. Simulation results show that the proposed DPMD scheme is comparative to the existing state-of-the-art dilution algorithm. The proposed design automation using the architectural mapping scheme reduces the required chip area and, hence, minimizes the valve switching that, in turn, increases the life span of the PMD-chip.
【學術交流】華盛頓大學黃正能教授演講
(國立交通大學資訊學院, 2019-03)
黃粵丞/資科工博士生
黃正能教授，於1981 和1983 年在台灣大學取得電子工程學士與碩士學位，並於1988 年在University of Southern California 取得博士學位。在1989 年在華盛頓大學任職，研究的領域為多媒體訊號處理、多媒體網路、影像處理、電腦視覺及圖形識別，已在國際期刊、國際會議論文集、書籍和書籍章節發表超過300 篇研究論文。黃正能教授於10 月21 日應邀蒞臨資訊學院演講，講題為：Coordinated Visual 3D Physical World Exploration for Smart City，本次演講探討3D 視覺技術如何應用在未來的智慧城市發展，旁及一些有趣的研究方向，並討論相關的理論基礎及研究成果。
Control of plasmon dephasing time using stacked nanogap gold structures for strong near-field enhancement
(2019-03-01)
Ueno, Kosei
;
Yang, Jinghuan
;
Sun, Quan
;
Aoyo, Daisuke
;
Yu, Han
The construction of metallic nanostructures with strong near-field enhancement is becoming increasingly significant for the practical use of plasmonic devices, such as plasmonic sensors and light-energy conversion systems. Importantly, the near-field enhancement effect depends on the plasmon dephasing time. Here, we propose a method for controlling plasmon dephasing time by utilizing plasmonic coupling for stronger near-field enhancement. Ordered arrays of stacked nanogap gold (Au) structures composed of a metal/insulator/metal nanostructure were fabricated by electron beam lithography and dry etching processes on a niobium-doped titanium dioxide substrate. The dark plasmon mode was excited by the near-field coupling between the upper and lower Au nanostructures separated by an alumina layer with a thickness of 15 nm. A strong near-field enhancement effect was induced by the localization of the electromagnetic field between the upper and lower Au nanostructures and the longer plasmon dephasing time based on the excitation of the dark plasmon mode. It is noteworthy that the dephasing time of the dark plasmon mode measured by time-resolved photoemission electron microscopy was extended 3-fold compared with that of the plasmon mode of the Au nanoblock, which can be controlled by the structural design of the stacked nanogap Au structures. (C) 2018 Elsevier Ltd. All rights reserved.
Adhesion and Material Properties Between Polyimide and Passivation Layers for Polymer/Metal Hybrid Bonding in 3-D Integration
(2019-03-01)
Lu, Cheng-Hsien
;
Kho, Yi-Tung
;
Chen, Chiao-Pei
;
Tsai, Bin-Ling
;
Chen, Kuan-Neng
This paper investigates polymer/metal hybrid bonding structure using conventional polyimide and modified polyimide-like material. Adhesion properties between bonding material and passivation layer were evaluated by four-point bending method, atomic force microscopy, water contact angle measurement, and X-ray photoelectron spectroscopy. Various annealing temperatures were applied to verify the reliability under thermal stress. The results show that the modified polyimide-like material with the curing temperature below 250 degrees C has better adhesion than the conventional polyimide. This modified polyimide material can be used in low-temperature hybrid bonding technology for advanced integration.
Influence of basal stacking faults on luminescence of m-plane Mg0.19Zn0.81O/ZnO quantum wells grown on a two-step MgZnO-buffer layer
(2019-03-01)
Wu, Yung-Chi
;
Chang, Ning-An
;
Yang, Tsung-Han
;
Tsai, Chih-Ya
;
Chen, Hou-Ren
Different well widths of m-plane Mg0.19Zn0.81O/ZnO multiple quantum wells (MQWs) have been fabricated on the two-step pregrown MgZnO-buffered m-plane sapphires by a pulsed laser deposition and have a narrower linewidth on x-ray diffraction than ZnO-buffered MQWs. By using the variation method to calculate the band diagram and by corroborating the results of temperature-dependent photoluminescence, we confirm the binding energies of free exciton and basal-stacking-fault-bound exciton, which is composed of electrons in the barrier and confined hole in the narrow-width MQWs. The coupling of A1(LO) phonon with excitons in m-MQWs shows more sensitivity toward a decrease in well width than E2(low), due to the crystal symmetry and the reduced Bohr radius. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)
[2.2.2.2](2,7)-1-Bromonaphthalenophane from a Desymmetrized Building Block Bearing Electrophilic and Masked Nucleophilic Functionalities
(2019-03-01)
Cai, Guangke
;
Chatterjee, Shreyam
;
Hisaki, Ichiro
;
Tobe, Yoshito
;
應用化學系
In search of 2,7-ethylene-bridged naphthalenophanes with desymmetrized naphthalene cores as inherently chiral cyclophanes, nucleophilic substitution of 1-bromo-7-(bromomethyl)-2-[(trimethylsilyl)methyl]naphthalene, a desymmetrized building block bearing an electrophilic group (CH2Br) and a masked nucleophilic functionality (CH2TMS) which can be activated by fluoride anion, was examined. As a result, in contrast to the case of parent naphthalenophanes wherein the smallest [2.2]naphthalenophane was obtained as the major product, only [2.2.2.2](2,7)-1-bromonaphthalenophane was obtained albeit in low yields, whereas the corresponding [2.2]- or [2.2.2]naphthalenophanes were not obtained. Though the [2.2.2.2]-1-bromonaphthalenophane can adopt four idealized geometries of different symmetry, among which three are inherently chiral, theoretical calculations predict that three conformers have almost equal energy and may equilibrate in solution. The X-ray crystallographic study shows that it adopts a C-2 conformation with anti,anti,anti orientation of the C-Br bonds at least as a major component in crystal.
A Novel Stretch Energy Minimization Algorithm for Equiareal Parameterizations
(2019-03-01)
Yueh, Mei-Heng
;
Lin, Wen-Wei
;
Wu, Chin-Tien
;
Yau, Shing-Tung
;
應用數學系
Surface parameterizations have been widely applied to computer graphics and digital geometry processing. In this paper, we propose a novel stretch energy minimization (SEM) algorithm for the computation of equiareal parameterizations of simply connected open surfaces with very small area distortions and highly improved computational efficiencies. In addition, the existence of nontrivial limit points of the SEM algorithm is guaranteed under some mild assumptions of the mesh quality. Numerical experiments indicate that the accuracy, effectiveness, and robustness of the proposed SEM algorithm outperform the other state-of-the-art algorithms. Applications of the SEM on surface remeshing, registration and morphing for simply connected open surfaces are demonstrated thereafter. Thanks to the SEM algorithm, the computation for these applications can be carried out efficiently and reliably.
Major bleeding risk of endoscopic sphincterotomy versus endoscopic papillary balloon dilatation in hemodialysis patients
(2019-03-01)
Tsai, Ming-Chang
;
Wang, Chi-Chih
;
Wang, Yao-Tung
;
Yang, Tzu-Wei
;
Chen, Hsuan-Yi
Background/Aims: Endoscopic sphincterotomy (EST) and endoscopic papillary balloon dilatation (EPBD) are used for therapeutic endoscopic retrograde cholangiopancreatography (ERCP). The postprocedure bleeding rate for EPBD is low in the normal population; however, this bleeding rate in a group of patients prone to bleeding, such as patients with end-stage renal disease, is not well-established. We therefore evaluated the post-EST and post-EPBD bleeding rate among hemodialysis (HD) patients based on data from Taiwan's National Health Insurance Research Database (NHIRD). Patients and Methods: The NHIRD entries for a population of 2 million were screened for patients who had a catastrophic illness card for HD between 1st January 2004 and 31st December 2011 and these patients were enrolled as research subjects. The rates of major gastrointestinal tract bleeding events appearing within 14 days after EST or EPBD were compared between HD and non-HD patients. Results: A total of 3561 patients, over 18 years of age and without liver cirrhosis or hematologic diseases, underwent 3826 EST and 280 EPBD procedures during the 8 calendar years selected for our analysis. The total post-ERCP major bleeding rate was much higher in HD than in non-HD patients (8.64% vs. 2.16%, P < 0.0001). The rate of postprocedure major bleeding events was lower for non-HD patients who underwent EPBD than those who underwent EST (0.75% vs. 2.26%; P = 0.049), whereas the postprocedure major bleeding event rates were similar in HD patients who underwent either EPBD or EST (8.70% vs. 8.33%; P = 0.484). Conclusion: Post-ERCP, post-EST, and post-EPBD major bleeding rates were all higher in HD patients in this study. EPBD resulted in lower postprocedure major bleeding events than EST in the non-HD population, but it failed to provide the reduction in bleeding events needed to perform endoscopic hemostasis in HD patients.
The Development of CMOS Amperometric Sensing Chip with a Novel 3-Dimensional TiN Nano-Electrode Array
(2019-03-01)
Lien, Chun-Lung
;
Yuan, Chiun-Jye
;
交大名義發表
;
生物科技學系
;
分子醫學與生物工程研究所
An electrochemical sensing chip with an 8 x 8 array of titanium nitride three-dimensional nano-electrodes (TiN 3D-NEA) was designed and fabricated via a standard integrated complementary metal oxide semiconductor process. Each nano-electrode in 3D-NEA exhibited a pole-like structure with a radius of 100 nm and a height of 35 nm. The numeric simulation showed that the nano-electrode with a radius of around 100 nm exhibited a more uniformly distributed electric field and a much higher electric field magnitude compared to that of the microelectrode. Cyclic voltammetry study with Ru(NH3)(6)(3+) also revealed that the TiN 3D-NEA exhibited a much higher current density than that obtained from the microelectrode by two orders of magnitude. Further studies showed that the electrocatalytical reduction of hydrogen peroxide (H2O2) could occur on a TiN 3D-NEA-based sensing chip with a high sensitivity of 667.2 mAmM(-1)cm(-2). The linear detection range for H2O2 was between 0.1 M and 5 mM with a lowest detection limit of 0.1 M. These results indicated that the fabricated TiN 3D-NEA exhibited high catalytic activity and sensitivity to H2O2 and could be a promising sensor for H2O2 measurement.
Ribose-5-phosphate isomerase A overexpression promotes liver cancer development in transgenic zebrafish via activation of ERK and beta-catenin pathways
(2019-03-01)
Chou, Yu-Ting
;
Chen, Li-Yang
;
Tsai, Shin-Lin
;
Tu, Hsiao-Chen
;
Lu, Jeng-Wei
Dysregulation of the enzymes involved in the pentose phosphate pathway (PPP) is known to promote tumorigenesis. Our recent study demonstrated that ribose-5-phosphate isomerase (RPIA), a key regulator of the PPP, regulates hepatoma cell proliferation and colony formation. Our studies in zebrafish reveal that RPIA-mediated hepatocarcinogenesis requires extracellular signal-regulated kinase (ERK) and beta-catenin signaling. To further investigate RPIA-mediated hepatocarcinogenesis, two independent lines of transgenic zebrafish expressing human RPIA in the liver were generated. These studies reveal that RPIA overexpression triggers lipogenic factor/enzyme expression, steatosis, fibrosis and proliferation of the liver. In addition, the severity of fibrosis and the extent of proliferation are positively correlated with RPIA expression levels. Furthermore, RPIA-mediated induction of hepatocellular carcinoma (HCC) requires the ERK and beta-catenin signaling pathway but is not dependent upon transaldolase levels. Our study presents a mechanism for RPIA-mediated hepatocarcinogenesis and suggests that RPIA represents a valuable therapeutic target for the treatment of HCC.
Standardization Status of Immersive Video Coding
(2019-03-01)
Wien, Mathias
;
Boyce, Jill M.
;
Stockhammer, Thomas
;
Peng, Wen-Hsiao
;
資訊工程學系
Based on increasing availability of capture and display devices dedicated to immersive media, coding, and transmission of these media has recently become a highest-priority subject of standardization. Different levels of immersiveness are defined with respect to an increasing degree of freedom in terms of movements of the observer within the immersive media scene. The level ranges from three degrees of freedom allowing the user to look around in all directions from a fixed point of view to six degrees of freedom, where the user can freely alter the viewpoint within the immersive media scene. The moving pictures experts group (MPEG) of ISO/IEC is developing a standards suite on "Coded Representation of Immersive Media," called MPEG-I, to provide technical solutions for building blocks of the media transmission chain, ranging from architecture, systems tools, coding of video and audio signals, to point clouds and timed text. In this paper, an overview on recent and ongoing standardization efforts in this area is presented. While some specifications, such as high efficiency video coding or version 1 of the omnidirectional media format, are already available, other activities are under development or in the exploration phase. This paper addresses the status of these efforts with a focus on video signals, indicates the development timelines, summarizes the main technical details, and provides pointers to further points of reference.