Browsing by Issue Date, starting with "2019-03-02"

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Perovskite CsPbBr3 Quantum Dots Prepared Using Discarded Lead-Acid Battery Recycled Waste
(2019-03-02)
Chen, Lung-Chien
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Tien, Ching-Ho
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Ou, Sin-Liang
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Lee, Kun-Yi
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Tian, Jianjun
Perovskite CsPbBr3 quantum dot (CsPbBr3-QD) recovery was performed using lead scrap from lead storage batteries. The perovskite CsPbBr3-QD characteristics were analyzed using different PbO/recycled PbO2 ratios. Scanning electron microscopy (SEM) was used to observe the film surface morphology and cross-section. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were used to observe the perovskite CsPbBr3-QDs' structural characteristics. A photoluminescence (PL) measurement system was used to analyze the optical properties. The results show that lead scrap from lead-acid batteries as a material for perovskite CsPbBr3-QD production can be successfully synthesized. This saves material and also proves that recycling is valuable. The proposed approach is helpful for future material shortages and materials not easily accessible. Although the efficiency is not very high, this process will be purified using recycled lead in the future to achieve higher quantum yield.
Dielectric Spectroscopy Using Dual Reflection Analysis of TDR Signals
(2019-03-02)
Ngui, Yin Jeh
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Lin, Chih-Ping
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Wu, Tsai-Jung
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土木工程學系
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Department of Civil Engineering
Time-domain reflectometry (TDR) has been a powerful tool for measuring soil dielectric properties. Initiating from apparent dielectric constant (Ka) measurement up until apparent and complex dielectric spectroscopies, the embedded information in the TDR signal can be extracted to inspire our understanding of the underlying dielectric behaviors. Multiple full waveform inversion techniques have been developed to extract complex dielectric permittivity (CDP) spectrum, but most of them involved prior knowledge of input function and tedious calibration. This rendered the field dielectric spectroscopy challenging and expensive to conduct. Dual reflection analysis (DRA) is proposed in this study to measure CDP spectrum from 10 MHz to 1 GHz. DRA is a simple, robust, model-free, and source-function free algorithm which requires minimal calibration effort. The theoretical framework of DRA is established and the necessary signal processing procedures are elaborated in this study. Eight materials with different dielectric characteristics are selected to evaluate DRA's performance, by using both simulated and experimental signals. DRA is capable of measuring non-dispersive materials very well, whereas dispersive materials require the assistance of a long-time-window (LTW) extraction method to further extend the effective bandwidth. The DRA approach is suitable for field applications that can only record a limited amount of data points and in-situ dielectric spectroscopy.
Sampling efficiency of low-volume PM10 inlets with different impaction substrates
(2019-03-04)
Thi-Cuc Le
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Shukla, Krishna Kumar
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Sung, Jung-Che
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Li, Ziyi
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Yeh, Huajun
The louvered 16.7 L min(-1) PM10 inlet is commonly used in PM10 and PM2.5 FRM samplers or FEM monitors. Its sampling efficiency is influenced by particle bounce, re-entrainment, and overloading since the PM10 inlet contains a PM10 impactor with an uncoated impaction surface. In this study, a modified PM10 (M-PM10) inlet with an oil-soaked glass fiber filter substrate supported by an oil-soaked porous metal disc was developed to eliminate the particle bounce and overloading effects. The oiled M-PM10 inlet and the traditional PM10 inlets with and without grease coating were collocated at the field for long-term comparison tests. The results show that the traditional uncoated PM10 inlet which is cleaned initially but not cleaned daily afterwards oversamples PM10 concentration after one 24-h sampling day and has the high positive average sampling bias during 14 sampling days due to particle bounce and re-entrainment. The grease-coated PM10 inlet without daily cleaning shows a better performance with a smaller sampling bias, but it still oversamples PM10 concentrations after the first three 24-h sampling days and then undersamples after 10 sampling days due to particle bounce and overloading effects, respectively. In comparison, the M-PM10 inlet shows a good performance with a small average sampling bias during 35 sampling days since vacuum oil wicks up through the deposit to eliminate particle bounce and overloading. It is suggested that the oiled M-PM10 inlet can be used to replace the traditional EPA PM10 inlet and for long-term sampling of over 1 month without the frequent maintenance need. Copyright (c) 2019 American Association for Aerosol Research
Polarization-dependent XEOL: Comparison of peculiar near-band-edge emission of non-polar alpha-plane GaN and ZnO wafers
(2019-03-04)
Lin, Bi-Hsuan
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Wu, Yung-Chi
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Lee, Jyh-Fu
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Tang, Mau-Tsu
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Hsieh, Wen-Feng
Polarization-dependent hard X-ray excited optical luminescence (XEOL) spectroscopy was used to study the properties of near-band-edge (NBE) emission of non-polar alpha-GaN and alpha-ZnO wafers. We found similar behaviors of alpha-GaN with alpha-ZnO that include the positive intensity jump and the blue shift of the NBE emission peak in the XEOL spectrum following the polarization-dependent X-ray absorption near-edge structure (XANES) as the X-ray energy is tuned across the Ga or Zn K-edge. Furthermore, as the X-ray energy is set above the K-edges, different oscillations of XEOL, also following the XANES, were observed depending upon the directions of the excitation X-ray electric field. However, the blue shift of alpha-ZnO is about two times larger than that of alpha-GaN that results from the larger polar field in alpha-ZnO than that in alpha-GaN. For both alpha-GaN and alpha-ZnO, the above K-edge excited oscillations in XANES and XEOL spectra, where the polarization is set parallel to the pi-axis, are attributed to simultaneous excitations of the p-bond along the pi-axis and in-plane sigma-bonds, whereas only the in-plane sigma-bonds are excited for the polarization perpendicular to the pi-axis. Therefore, these polarization dependent oscillation features of XEOL yields that follow the fluorescence yields can be used as an alternative way to determine the crystallographic orientations. Published under license by AIP Publishing.
A note on Group Selection with multiple quality characteristics: power comparison of two methods
(2019-03-04)
Pearn, W. L.
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Lin, Chen-ju
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Chen, Y. H.
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Huang, J. Y.
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工業工程與管理學系
The Group Selection problem is an essential problem in the supplier selection process. The objective of the problem is to select a subset of suppliers containing the best among multiple candidate suppliers. Manufacturers should procure parts from the selected suppliers to produce high-quality products. Lin, C.J., W.L. Pearn, J.Y. Huang, and Y.H. Chen [2017. "Group Selection for Processes with Multiple Quality Characteristics." Communications in Statistics - Theory and Methods. doi:] considered the problem under multiple quality characteristics, and proposed the Modified Bonferroni method and the Multiple Comparisons with the Best (MCB) method to tackle the problem. The two methods, however, may select different subset containing the best depending on the magnitude of the differences among the k estimated index values. In this paper, we derive the power function for the Modified Bonferroni method, and compare the power of the two methods with extensive simulations. The results show that the MCB method is more powerful than the Modified Bonferroni method when the actual number of the best process is one. On the other hand, the Modified Bonferroni method significantly outperforms the MCB method when the actual number of the best process is greater than one. The results provide practitioners with useful reference about the properties of the two methods for supplier selection.
Impact of barrier layer on HfO2-based conductive bridge random access memory
(2019-03-04)
Lin, Chun-An
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Huang, Chu-Jie
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Tseng, Tseung-Yuen
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this letter, we report the impact of the barrier layer on the performance of HfO2-based conductive bridge RAM (CBRAM) devices with TeTiW as the source layer. The considerable improvement of retention in the CBRAM device using TiW as the barrier layer is attributed to the lower amount of oxygen vacancies in the switching layer, which is justified from the O1s core level in X-ray photoelectron spectroscopy analyses. Therefore, the diffusion of Te in the resistive layer of the device with the TiW barrier layer is limited even at high temperature. The TeTiW/TiW/HfO2/TiN CBRAM device provides an excellent endurance of more than 10(4) cycles, with an on/off ratio of 200. Such a device also features long retention for up to 10(4) s at 200 degrees C.
Luminescence material characterizations on laser-phosphor lighting techniques
(2019-03-04)
Yeh, Chih-Ting
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Chou, Yen-, I
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Yang, Kai-Shing
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Wu, Shih-Kuo
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Wang, Chi-Chuang
This study examines three different types of laser carriers, including the phosphors in silicone (PiS), the phosphor in glass (PiG), and alumina-based ceramic binders (CP), for laser-phosphor lighting characterizations via a laser projector light source module. The thermal influence of heat spreading on these phosphor materials and their luminescence performance is also investigated. The conversion efficiency of PiS, PiG and CP was found to be 29.7%, 34.6% and 31.8%, with their corresponding maximum laser power operations of 3.9 W, 7.9 W, and 17.2 W, respectively. This work further correlates the maximum laser operation power with the thermal conductivity of luminescence material. From the optical engine perspective, it was found that CP exhibits the superior thermal conductivity of 17.0 W/m.K for slight hot-spot IR observation and higher laser power operation. This work finally delivers a CP device for 50.2W maximum laser operation with the operating temperature below 100 degrees C. The simulation is also carried out in order to examine spreading resistance's influence, when subject to convective boundary condition. CP's response sensitivity to heat transfer coefficient was found to be rather small. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Linking safety knowledge to safety behaviours: a moderated mediation of supervisor and worker safety attitudes
(2019-03-04)
Kao, Kuo-Yang
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Spitzmueller, Christiane
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Cigularov, Konstantin
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Thomas, Candice L.
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管理科學系
The thousands of deaths and disabilities due to workplace accidents and injuries each year emphasize the importance of safety research. Despite occupational safety research that has contributed to identifying antecedents of safety, little is known about why and how safety knowledge leads to safety behaviours and how personal and situational factors interact to promote occupational safety. Using a multilevel, multisource, and time-lagged research design, the present study investigates whether safety knowledge affects safety behaviours through safety attitudes and further tests whether supervisory safety attitudes can impact the strength of these relationships and play a role as moderators of the proposed mediated relationship. Data were collected from workers (N = 177) and supervisors (N = 42) in a construction company in the energy industry at two time points. Results indicate full support for the moderated mediation model, demonstrating that worker safety attitudes partially mediate the relationship between safety knowledge and safety behaviours. Moreover, when supervisors had positive attitudes towards safety, both the direct relationship between worker safety attitudes and safety behaviours and the indirect relationship between safety knowledge and safety behaviours were more positive compared to when supervisors had negative safety attitudes. Theoretical and practical implications for occupational safety are discussed.
Enhanced bioconjugation on sputtered palladium nano-thin-film electrode
(2019-03-04)
Chang, Chia-Yu
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Chen, Wei
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Su, Chien-Hao
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Chang, Pang-Chia
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Huang, Yun-Tzu
A highly reactive surface with an enhanced ability for chemical bonding relies on the presence of specifically coordinated atoms and step edges at the surface. In this study, an electrode with a unique Stranski-Krastanov-like thin film, with an epitaxial sputtering of a palladium (Pd) nanoparticle double layer on the polyethylene terephthalate substrate, was developed. On the surface of this flexible Pd-nano-thin-film (NTF) electrode with a (1 1 1) containing surface, DNA probes can be quickly immobilized in as short a period as 20 min, which is 24 times faster than that on the gold electrode. A DNA-based anticancer compound (ACC) sensing and screening process that would use the DNA functionalized Pd-NTF electrode as the biosensor was then proposed. Interestingly, the developed biosensor could detect DNA and ACCs, such as doxorubicin, tetra-O-methyl nordihydroguaiaretic acid, and Taxol via interactions with solutions containing 1 mu l ACCs within 11 min, and the sensitivity of the ACC solution is similar to 0.1 mu M (similar to 36 pg per-test), as detected by electrochemical impedance spectroscopy. Moreover, this highly reactive surface can be used in regular sensors and other interfaces, in scientific applications. (C) 2019 Author(s).
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
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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.