Browsing by Issue Date, starting with "2019-03-05"

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Sensitivity Enhancement of Acetone Gas Sensor using Polyethylene Glycol/Multi-Walled Carbon Nanotubes Composite Sensing Film with Thermal Treatment
(2019-03-05)
Chiou, Jin-Chern
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Wu, Chin-Cheng
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Lin, Tse-Mei
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電子工程學系及電子研究所
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電控工程研究所
There is a need to develop a chemiresistive gas sensor equipped with a thermostat over a wide area for the sensor, which can protect the sensor from the influence of ambient temperature due to the uniform temperature of the thermostat. In this paper, we demonstrated an acetone gas sensor based on a polyethylene glycol (PEG)/Multi-walled Carbon Nanotubes (MWCNTs) composite film, which was equipped with a thermostat. The sensor was operated at modest working temperatures for sensor sensitivity enhancement. The optimum design of the polyimide-based thermostat with widely uniform thermal distribution was investigated in detail. It was found that the temperature uniformity of the thermostat was achieved using double spiral geometry. The experimental results of the sensor response showed that the PEG/MWCNTs composite film with a moderate working temperature revealed a higher sensitivity than that without thermal treatment. Moreover, the sensing mechanisms of the PEG/MWCNTs composite gas sensor to acetone vapor were studied as well.
交大e-News第273期-多項首創學習途徑！交大「跨域學習∞共創無限」聯展呈現創新教學成果
(2019-03-05)
國立交通大學秘書室
;
Secretariat
磚木取夥　每次轉彎都是一道風景
(國立交通大學傳播與科技學系, 2019-03-06)
田詠葳
新竹縣新埔鎮的「磚木取夥故事劇場」，有別於一般人對劇場要有著華麗裝潢、氣派觀眾席的印象，走進磚木取夥彷彿是回家一樣。期許這樣的空間能夠創造出更多活動，為新埔注入一股藝文新活力。
Cooperative Carrying Control for Multi-Evolutionary Mobile Robots in Unknown Environments
(2019-03-06)
Jhang, Jyun-Yu
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Lin, Cheng-Jian
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Young, Kuu-Young
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電控工程研究所
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Institute of Electrical and Control Engineering
This study provides an effective cooperative carrying and navigation control method for mobile robots in an unknown environment. The manager mode switches between two behavioral control modes-wall-following mode (WFM) and toward-goal mode (TGM)-based on the relationship between the mobile robot and the unknown environment. An interval type-2 fuzzy neural controller (IT2FNC) based on a dynamic group differential evolution (DGDE) is proposed to realize the carrying control and WFM control for mobile robots. The proposed DGDE uses a hybrid method that involves a group concept and an improved differential evolution to overcome the drawbacks of the traditional differential evolution algorithm. A reinforcement learning strategy was adopted to develop an adaptive WFM control and achieve cooperative carrying control for mobile robots. The experimental results demonstrated that the proposed DGDE is superior to other algorithms at using WFM control. Moreover, the experimental results demonstrate that the proposed method can complete the task of cooperative carrying, and can realize navigation control to enable the robot to reach the target location.
Thermopneumatic suction integrated microfluidic blood analysis system
(2019-03-07)
Yang, Chiao-Hsun
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Hsieh, Yu-Ling
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Tsou, Ping-Hsien
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Li, Bor-Ran
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交大名義發表
Blood tests provide crucial diagnostic information regarding several diseases. A key factor that affects the precision and accuracy of blood tests is the interference of red blood cells; however, the conventional methods of blood separation are often complicated and time consuming. In this study, we devised a simple but high-efficiency blood separation system on a self-strained microfluidic device that separates 99.7 +/- 0.3% of the plasma in only 6 min. Parameters, such as flow rate, design of the filter trench, and the relative positions of the filter trench and channel, were optimized through microscopic monitoring. Moreover, this air difference-driven device uses a cost-effective and easy-to-use heater device that creates a low-pressure environment in the microchannel within minutes. With the aforementioned advantages, this blood separation device could be another platform choice for point-of-care testing.
Previously published drug interaction models predict loss of response for transoesophageal echocardiography sedation well but not response to oesophageal instrumentation
(2019-03-07)
Su, Fu-Wei
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Ting, Chien-Kun
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Liou, Jing-Yang
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Chen, Yi-Chang
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Tsou, Mei-Yung
Response surface models (RSMs) were used to predict effects of multiple drugs interactions. Our study was aimed to validate accuracy of the previous published volunteer models during transoesophageal echocardiography (TEE). This is a cross-sectional study with 20 patients scheduled for transesophageal echocardiography in Taipei Veterans General Hospital, Taiwan. Effect-site concentration pairs of alfentanil and propofol were recorded and converted to equivalent remifentanil and propofol effect-site concentrations. Observer's Assessment of Alertness/Sedation (OAA/S) scores were assessed every 2 minutes. Using these data, previous published models of loss of response (LOR), intolerable ventilatory depression (IVD), and loss of response to esophageal instrumentation (LREI) were then estimated. Accuracy of prediction is assessed by calculating the difference between the true response and the model-predicted probability. Clinical events such as interruption of TEE were recorded. The average procedure time was 11 minutes. Accuracy for prediction of LOR and LREI is 63.6% and 38.5%, respectively. There were four patients experienced desaturation for less than 1 minute, which were not predicted by IVD model, and one interruption of TEE due to involuntary movement. The previous published drug-interaction RSMs predict LOR well but not LREI for TEE sedation. Further studies using response surface methodology are needed to improve quality for TEE sedation and clinical implementation.
TACCO, a Database Connecting Transcriptome Alterations, Pathway Alterations and Clinical Outcomes in Cancers
(2019-03-07)
Chou, Po-Hao
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Liao, Wei-Chao
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Tsai, Kuo-Wang
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Chen, Ku-Chung
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Yu, Jau-Song
Because of innumerable cancer sequencing projects, abundant transcriptome expression profiles together with survival data are available from the same patients. Although some expression signatures for prognosis or pathologic staging have been identified from these data, systematically discovering such kind of expression signatures remains a challenge. To address this, we developed TACCO (Transcriptome Alterations in CanCer Omnibus), a database for identifying differentially expressed genes and altered pathways in cancer. TACCO also reveals miRNA cooperative regulations and supports construction of models for prognosis. The resulting signatures have great potential for patient stratification and treatment decision-making in future clinical applications. TACCO is freely available at http://tacco.life.nctu.edu.tw/.
A Light Guide Plate That Uses Asymmetric Intensity Distribution of Mini-LEDs for the Planar Illuminator
(2019-03-08)
Ye, Zhi-Ting
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Pai, Yung-Min
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Chen, Cheng-Huan
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Kuo, Hao-Chung
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Chen, Lung-Chien
Traditional backlights are designed with new dot patterns, and then injection molding, laser beam fabrication, or UV (Ultraviolet) roll-to-plate imprinting is used to apply dot patterns to a light guide plate-the process consumes considerable time and resources. Therefore, we propose a novel light guide design that does not use a dot pattern. We designed an asymmetric intensity distribution of mini-LEDs (Light Emitting Diode) and a light guide plate with a fully printed diffusion reflection on the bottom surface for a planar illuminator. The design rules for the proposed architecture are described in this paper. The archetype design with a 152.4 mm circular down-light has a diameter of 143 mm for the planar light source module. The experiment achieved a total efficiency of 85% and uniformity of 92.6%.
Atomically thin van der Waals tunnel field-effect transistors and its potential for applications
(2019-03-08)
Yang, Shih-Hsien
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Yao, You-Teng
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Xu, Yong
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Lin, Che-Yi
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Chang, Yuan-Ming
Power dissipation is a crucial problem as the packing density of transistors increases in modern integrated circuits. Tunnel field-effect transistors (TFETs), which have high energy filtering provided by band-to-band tunneling (BTBT), have been proposed as an alternative electronics architecture to decrease the energy loss in bias operation and to achieve steep switching at room temperature. Very recently, the BTBT behavior has been demonstrated in van der Waals heterostructures by using unintentionally doped semiconductors. The reason of the BTBT formation is attributed to a significant band bending near the heterointerface, resulting in carrier accumulations. In this work, to investigate charge transport in type-III transistors, we adopted the same band-bending concept to fabricate van der Waals BP/MoS2 heterostructures. Through analyzing the temperature dependence of their electrical properties, we carefully ruled out the contribution of metal-semiconductor contact resistances and improved our understanding of carrier injection in 2D type-III transistors. The BP/MoS2 heterostructures showed both negative differential resistance and 1/f(2) current fluctuations, strongly demonstrating the BTBT operation. Finally, we also designed a TFET based on this heterostructure with an ionic liquid gate, and this TFET demonstrated an subthreshold slope can successfully surmount the thermal limit of 60 mV/decade. This work improves our understanding of charge transport in such layered heterostructures and helps to improve the energy efficiency of next-generation nanoscale electronics.
Third-Order Polynomial Normal Transform Applied to Multivariate Hydrologic Extremes
(2019-03-08)
Tung, Yeou-Koung
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You, Lingwan
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Yoo, Chulsang
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防災與水環境研究中心
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Disaster Prevention and Water Environment Research Center
Hydro-infrastructural systems (e.g., flood control dams, stormwater detention basins, and seawalls) are designed to protect the public against the adverse impacts of various hydrologic extremes (e.g., floods, droughts, and storm surges). In their design and safety evaluation, the characteristics of concerned hydrologic extremes affecting the hydrosystem performance often are described by several interrelated random variables-not just one-that need to be considered simultaneously. These multiple random variables, in practical problems, have a mixture of non-normal distributions of which the joint distribution function is difficult to establish. To tackle problems involving multivariate non-normal variables, one frequently adopted approach is to transform non-normal variables from their original domain to multivariate normal space under which a large wealth of established theories can be utilized. This study presents a framework for practical normal transform based on the third-order polynomial in the context of a multivariate setting. Especially, the study focuses on multivariate third-order polynomial normal transform (TPNT) with explicit consideration of sampling errors in sample L-moments and correlation coefficients. For illustration, the modeling framework is applied to establish an at-site rainfall intensity-duration-frequency (IDF) relationship. Annual maximum rainfall data analyzed contain seven durations (1-72 h) with 27 years of useable records. Numerical application shows that the proposed modeling framework can produce reasonable rainfall IDF relationships by simultaneously treating several correlated rainfall data series and is a viable tool in dealing with multivariate data with a mixture of non-normal distributions.
A general analytical model for head response to oscillatory pumping in unconfined aquifers: effects of delayed gravity drainage and initial condition
(2019-03-08)
Huang, Ching-Sheng
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Tsai, Ya-Hsin
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Yeh, Hund-Der
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Yang, Tao
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環境工程研究所
Oscillatory pumping tests (OPTs) provide an alternative to constant-head and constant-rate pumping tests for determining aquifer hydraulic parameters when OPT data are analyzed based on an associated analytical model coupled with an optimization approach. There are a large number of analytical models presented for the analysis of the OPT. The combined effects of delayed gravity drainage (DGD) and the initial condition regarding the hydraulic head are commonly neglected in the existing models. This study aims to develop a new model for describing the hydraulic head fluctuation induced by the OPT in an unconfined aquifer. The model contains a groundwater flow equation with the initial condition of a static water table, Neumann boundary condition specified at the rim of a partially screened well, and a free surface equation describing water table motion with the DGD effect. The solution is derived using the Laplace, finite-integral, and Weber transforms. Sensitivity analysis is carried out for exploring head response to the change in each hydraulic parameter. Results suggest that the DGD reduces to instantaneous gravity drainage in predicting transient head fluctuation when the dimensionless parameter a(1) = epsilon S(y)b/K-z exceeds 500 with empirical constant epsilon, specific yield S-y, aquifer thickness b, and vertical hydraulic conductivity K-z. The water table can be regarded as a no-flow boundary when a(1) < 10(-2) and P < 10(4) s, with P being the period of the oscillatory pumping rate. A pseudo-steady-state model without the initial condition causes a time-shift from the actual transient model in predicting simple harmonic motion of head fluctuation during a late pumping period. In addition, the present solution agrees well with head fluctuation data observed at the Savannah River site. Highlights. An analytical model of the hydraulic head due to oscillatory pumping in unconfined aquifers is presented. Head fluctuations affected by instantaneous and delayed gravity drainages are discussed. The effect of the initial condition on the phase of head fluctuation is analyzed. The present solution agrees well with head fluctuation data taken from field oscillatory pumping.
Coordination-induced emission enhancement in gold-nanoclusters with solid-state quantum yields up to 40% for eco-friendly, low-reabsorption nano-phosphors
(2019-03-11)
Huang, Hsiu-Ying
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Cai, Kun-Bin
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Talite, Maria Jessabel
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Chou, Wu-Ching
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Chen, Po-Wen
Colloidal quantum dots (CQDs) have gained much attention as light-emitting materials for light-conversion nano-phosphors and luminescent solar concentrators. Unfortunately, those CQDs involve toxic heavy metals and frequently need to be synthesized in the hazardous organic solvent. In addition, they suffer from severe solid-state aggregation-induced self-quenching and reabsorption losses. To address these issues, here we prepare Zn-coordinated glutathione-stabilized gold-nanocluster (Zn-GSH-AuNCs) assemblies without involving heavy metals and organic solvent. Unlike GSH-AuNCs dispersed in an aqueous solution with poor photoluminescence quantum yields (PL-QYs, typically similar to 1%), those Zn-GSH-AuNCs powders hold high solid-state PL-QYs up to 40 +/- 5% in the aggregated state. Such Zn-induced coordination-enhanced emission (CEE) is attributed to the combined effects of suppressed non-radiative relaxation and enhanced charge-transfer interaction. In addition, they also exhibit a large Stokes shift, thus mitigating both aggregation-induced self-quenching and reabsorption losses. Motivated by these photophysical properties, we demonstrated white-light emission from all non-toxic, aqueous-synthesis nano-materials.
Effect of Metal Ions on Hybrid Graphite-Diamond Nanowire Growth: Conductivity Measurements from a Single Nanowire Device
(2019-03-11)
Shellaiah, Muthaiah
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Chen, Ying-Chou
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Simon, Turibius
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Li, Liang-Chen
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Sun, Kien Wen
Novel Cd2+ ions mediated reproducible hybrid graphite-diamond nanowire (G-DNWs; Cd2+-NDS1 NW) growth from 4-Amino-5-phenyl-4H-1,2,4-triazole-3-thiol (S1) functionalized diamond nanoparticles (NDS1) via supramolecular assembly is reported and demonstrated through TEM and AFM images. FTIR, EDX and XPS studies reveal the supramolecular coordination between functional units of NDS1 and Cd2+ ions towards NWs growth. Investigations of XPS, XRD and Raman data show the covering of graphite sheath over DNWs. Moreover, HR-TEM studies on Cd2+-NDS1 NW confirm the coexistence of less perfect sp(2) graphite layer and sp(3) diamond carbon along with impurity channels and flatten surface morphology. Possible mechanisms behind the G-DNWs growth are proposed and clarified. Subsequently, conductivity of the as-grown G-DNWs is determined through the fabrication of a single Cd2+-NDS1 NW device, in which the G-DNW portion L2 demonstrates a better conductivity of 2.31 x 10(-4) mS/cm. In addition, we investigate the temperature-dependent carrier transport mechanisms and the corresponding activation energy in details. Finally, comparisons in electrical resistivities with other carbon-based materials are made to validate the importance of our conductivity measurements.
Sample size calculations for model validation in linear regression analysis
(2019-03-12)
Jan, Show-Li
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Shieh, Gwowen
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管理科學系
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Department of Management Science
BackgroundLinear regression analysis is a widely used statistical technique in practical applications. For planning and appraising validation studies of simple linear regression, an approximate sample size formula has been proposed for the joint test of intercept and slope coefficients.MethodsThe purpose of this article is to reveal the potential drawback of the existing approximation and to provide an alternative and exact solution of power and sample size calculations for model validation in linear regression analysis.ResultsA fetal weight example is included to illustrate the underlying discrepancy between the exact and approximate methods. Moreover, extensive numerical assessments were conducted to examine the relative performance of the two distinct procedures.ConclusionsThe results show that the exact approach has a distinct advantage over the current method with greater accuracy and high robustness.
Performance comparison of III-V//Si and III-V//InGaAs multi-junction solar cells fabricated by the combination of mechanical stacking and wire bonding
(2019-03-13)
Kao, Yu-Cheng
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Chou, Hao-Ming
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Hsu, Shun-Chieh
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Lin, Albert
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Lin, Chien-Chung
The integration of III-V and Si multi-junction solar cells as photovoltaic devices has been studied in order to achieve high photovoltaic conversion efficiency. However, large differences in the coefficients of thermal expansion and the lattice parameters of GaAs, Si, and InGaAs have made it difficult to obtain high-efficiency solar cells grown as epilayers on Si and InP substrates. In this paper, two types of devices, including GaInP/GaAs stacked on Si (GalnP/GaAs//Si) and GaInP/GaAs stacked on InGaAs (GaInP/GaAs//InGaAs), are fabricated via mechanical stacking and wire bonding technologies. Mechanically stacked GaInP/GaAs//Si and GaInP/GaAsllInGaAs triple-junction solar cells are prepared via glue bonding. Current-voltage measurements of the two samples are made at room temperature. The short-circuit current densities of the GaInP/GaAs//Si and GaInP/GaAs//InGaAs solar cells are 13.37 and 13.66 mA/cm(2), while the open-circuit voltages of these two samples are measured to be 2.71 and 2.52V, respectively. After bonding the GaInP/GaAs dual-junction with the Si and InGaAs solar cells, the conversion efficiency is relatively improved by 32.6% and 30.9%, respectively, compared to the efficiency of the GaInP/GaAs dual-junction solar cell alone. This study demonstrates the high potential of combining mechanical stacked with wire bonding and ITO films to achieve high conversion efficiency in solar cells with three or more junctions.
Colorimetric and Fluorescent Dual-Mode Immunoassay Based on Plasmon-Enhanced Fluorescence of Polymer Dots for Detection of PSA in Whole Blood
(2019-03-13)
You, Pei-Yun
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Li, Fang-Chu
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Liu, Ming-Ho
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Chan, Yang-Hsiang
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應用化學系
Although enormous efforts have been devoted to the development of new types of fluorometric immuno-chromatographic test strip (ICTS) with improved sensitivity over the past years, it still remains a big challenge to design ICTS with colorimetric and fluorescent bimodal signal readout for rapid yet accurate detection of cancer markers in a clinic. Scientists have tried to prepare bimodal reporters by combining fluorescent dyes with metal nanomaterials, but their fluorescence was easily quenched by metal nanomaterials through surface energy transfer, making dual colorimetric and fluorometric ICTS very difficult to be achieved. As compared to conventional fluorescent probes, semiconducting polymer dots (Pdots) exhibit extraordinary fluorescence brightness and facile surface functionalization, which are very suitable to be engineered as bimodal signal reporting reagents. Here, we integrated highly fluorescent Pdots with strongly plasmonic Au nanorods to form Pdot-Au hybrid nanocomposites with dual colorimetric and fluorescent readout abilities. We further utilized these nanohybrids in ICTS for qualitatively fast screening (colorimetry) as well as quantitatively accurate determination (fluorometry) of prostate-specific antigen (PSA) within 10 min. By taking advantage of the plasmon-enhanced fluorescence of Pdots on Au nanorods, this immunoassay possesses much better detection sensitivity of 1.07 pg/mL for PSA, which is at least 2 orders of magnitude lower than that of conventional fluorometric ICTS. Moreover, the direct detection of PSA from human whole blood collected without sample pretreatment makes this Pdot-based ICTS platform promising for on-site point-of-care diagnostics.
Boron Doped Graphene Quantum Structure and MoS2 Nanohybrid as Anode Materials for Highly Reversible Lithium Storage
(2019-03-13)
Riyanto
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Sahroni, Imam
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Bindumadhavan, Kartick
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Chang, Pei-Yi
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Doong, Ruey-an
Herein, the boron-doped graphene quantum structure (BGQS), which contains both the advantages of 0-D graphene quantum dot and 2-D reduced graphene oxide, has been fabricated by top-down hydrothermal method and then mixed with molybdenum sulfide (MoS2) to serve as an active electrode material for the enhanced electrochemical performance of lithium ion battery. Results show that 30 wt% of BGQS/MoS2 nanohybrid delivers the superior electrochemical performance in comparison with other BGQS/MoS2 and bare components. A highly reversible capacity of 3,055 mAh g(-1) at a current density of 50mA g(-1) is achieved for the initial discharge and a high reversible capacity of 1,041 mAh g(-1) is obtained at 100mA g(-1) after 50 cycles. The improved electrochemical performance in BGQS/MoS2 nanohybrid is attributed to the well exfoliated MoS2 structures and the presence of BGQS, which can provide the vitally nano-dimensional contact for the enhanced electrochemical performance. Results obtained in this study clearly demonstrate that BGQS/MoS2 is a promising material for lithium ion battery and can open a pathway to fabricate novel 2-D nanosheeted nanocomposites for highly reversible Li storage application.
METHOD FOR MANUFACTURING WIDE-BANDGAP OXIDE EPITAXIAL FILM
(2019-03-14)
RAY-HUA HORNG
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YEN-CHU LI
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CHUN-YI TUNG
;
SI-HAN TSAI
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LI-CHUNG CHENG
The present invention provides a method for manufacturing a wide-bandgap oxide epitaxial film. An epitaxial film with superior physical properties, such as high saturated drift velocity of electrons, small dielectric constant, high thermal stability, and excellent high-temperature resistance, is formed on a substrate. In addition, because the oxide epitaxial film is grown by metal-organic chemical vapor deposition (MOCVD), the yield is improved significantly and defects in the epitaxy is reduced.
Femtosecond electronic relaxation and real-time vibrational dynamics in 2 '-hydroxychalcone
(2019-03-14)
Yamakita, Yoshihiro
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Yokoyama, Nanae
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Xue, Bing
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Shiokawa, Naoyuki
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Harabuchi, Yu
Femtosecond ultrafast electronic relaxation and vibrational dynamics in 2'-hydroxychalcone after deep ultraviolet (DUV) excitation were observed by two types of pump-probe spectroscopy experiments, i. e., DUV-pump pulse and visible-broadband-probe pulse (DUV/Vis) experiments and DUV-pump and DUV-probe (DUV/DUV) pulse experiments. Time-dependent density functional theory (TDDFT) calculations were performed to elucidate relaxation dynamics from the third singlet electronic excited state S-3. The DUV/Vis experiments and TDDFT calculations have disclosed the ultrafast dynamics of internal conversion from the initial S-3 state (tau(1) approximate to 35 fs) to the S-1 state via a rapid process through the S-3/S-2 conical intersection and proton transfer [OH: tau(2)(H) approximate to 93 and OD: tau(2)(D) approximate to 164 fs] before deactivation through the S-1/S-0 conical intersection (tau(3) approximate to 690 fs). Thanks to the ultrashort pump and probe pulses, real-time observation of vibrational modes coupled to the electronic excitation was realized providing both amplitudes and phases. Spectrogram analyses were performed based on the real-time spectra obtained by the DUV/Vis experiments, in which instantaneous vibrational frequencies reflecting molecular structural change after the impulsive excitation were visualized. The vibrational frequency of central C=C bond stretch decreases from similar to 1600 cm(-1) to similar to 1560 cm(-1) in about 200-500 fs and recovers in similar to 550 fs. Normal mode analyses along the decay path support the observed variation of the C=C stretching frequency. The temporal weakening of the central C=C bond is connected with the angle of the two aromatic rings which flip back to the initial conformation.
Effect of Etching Depth on Threshold Characteristics of GaSb-Based Middle Infrared Photonic-Crystal Surface-Emitting Lasers
(2019-03-14)
Li, Zong-Lin
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Lin, Shen-Chieh
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Lin, Gray
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Cheng, Hui-Wen
;
Sun, Kien-Wen
We study the effect of etching depth on the threshold characteristics of GaSb-based middle infrared (Mid-IR) photonic-crystal surface-emitting lasers (PCSELs) with different lattice periods. The below-threshold emission spectra are measured to identify the bandgap as well as band-edge modes. Moreover, the bandgap separation widens with increasing etching depth as a result of enhanced diffraction feedback coupling. However, the coupling is nearly independent of lattice period. The relationship between threshold gain and Bragg detuning is also experimentally determined for PCSELs and is similar to that calculated theoretically for one-dimensional distributed feedback lasers.