Browsing by Issue Date, starting with "2020-05-01"

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Effect of Rainfall, Runoff and Infiltration Processes on the Stability of Footslopes
(2020-05-01)
Chen, Hung-En
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Chiu, Yen-Yu
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Tsai, Tung-Lin
;
Yang, Jinn-Chuang
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防災與水環境研究中心
To analyze the effect of runoff on shallow landslides, a model coupling one-dimensional rainfall-runoff and two-dimensional infiltration was established to simulate rainfall, infiltration, and runoff processes. Based on Bishop's limit equilibrium method, the slope failure of a hypothetical footslope was studied. First, conditions with and without inflow were compared. The results reveal a remarkable difference in factors of safety (FS) between the two conditions, suggesting that considering the effect of runoff is crucial for landslide modeling. In terms of a series of tests of the various magnitudes, durations, lag-time, and peak position of the hydrograph, analyses show that larger inflow leads to more accumulated infiltration and triggers landslides earlier. A long-term duration inflow decreases the stability more than short intensive inflow does. With subsequent surface inflow, slope failure may occur after rainfalls stop, owing to the inflow, and the shape of inflow hydrographs could slightly affect the variance in FS. Results also indicate the necessity of considering the surface runoff when using a numerical model to analyze landslide, particularly on a footslope.
A highly selective fluorescent anthracene-based chemosensor for imaging Zn2+ in living cells and zebrafish
(2020-05-01)
Minh-Hai Nguyen
;
Thi-Nguyet Nguyen
;
Danh-Quang Do
;
Hung-Huy Nguyen
;
Quan-Manh Phung
A new fluorescent chemosensor (An3) bearing anthracenyl rings was designed and developed for detection of Zn2+. Addition of Zn2+ into An3 gave rise to a fluorescent turn-on response at 424 nm whereas Al3+, Cd (2+), Co2+, Cu2+, K+, Mg2+, Zn2+, Ca2+, Fe3+, Mn2+, Ni2+, Pb2+, and Hg2+ did not induce any emission intensity enhancement. Furthermore, the probe exhibited high selectivity toward Zn2+ and a very low detection limit (36 nM) based on chelation-enhanced fluorescence. Theoretical calculations revealed the possible formation of 1:1 and 1:2 complexes between An3 and Zn2+. In bioimaging experiments, the chemosensor displayed low cytotoxicity and good biocompatibility, rendering it an effective tool for fluorescent visualization of Zn2+ in living cells and zebrafish models.
Design Strategies for Mesa-Type GaN-Based Schottky Barrier Diodes for Obtaining High Breakdown Voltage and Low Leakage Current
(2020-05-01)
Jia, Xingyu
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Chen, Sung-Wen Huang
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Liu, Yajin
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Hou, Xu
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Zhang, Yonghui
In this article, we have systematically investigated the impact of different structural parameters on the breakdown voltage for GaN-based trench MIS barrier-controlled Schottky (TMBS) rectifier. Compared with the planar Schottky rectifier, the TMBS rectifier has field plates on the mesa sidewalls so that the drift region can be depleted in a 2-D manner, which helps to decrease the electric field at the metal/mesa interface. However, the adoption of mesas can make the electric potential lines at the mesa corner dense and has large curvatures. Therefore, the premature breakdown can occur when the electric field therein reaches the critical condition. We find that the electric field profiles can be affected by insulation layer thickness, mesa width, trench depth, and different types of insulation layers. Then, we increase the breakdown voltage by homogenizing the electric field distribution in the mesa region, e.g., the electric field at mesa corners can be decreased by adopting properly thick sidewall insulator and small trench depth. Meanwhile, TMBS rectifier using sidewall insulating material with a large dielectric constant more favors a large breakdown voltage.
Swivel-HEPA-ETT (SHE) bougie and HEPA-ETT (HE) methods for safe intubation while managing patients with COVID-19
(2020-05-01)
Lin, Li-Wei
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Hung, Tzu-Yao
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交大名義發表
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National Chiao Tung University
Numerical Simulation of Thermal Conductivity of SiNW-SiGe0.3 Composite for Thermoelectric Applications
(2020-05-01)
Lee, Ming-Yi
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Li, Yiming
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Chuang, Min-Hui
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Ohori, Daisuke
;
Samukawa, Seiji
The electron band structure and phonon energy dispersion of the silicon nanowires (SiNWs) embedded in SiGe0.3 (SiNW-SiGe0.3 composite) are simulated by using the effective mass Schrodinger equation and the elastodynamic wave equation, respectively. Then, the TE properties of the SiNW-SiGe0.3 composite are investigated by the Landauer approach. The simulation shows the contribution from electrons/holes on both electrical conductance and thermal conductance increases few times by introducing SiNWs, but on the other hand, lattice thermal conductance reduces around two orders. These results are consistent with the experimental measurement and indicates that much lower lattice thermal conductance dominates the TE performance of the SiNW-SiGe0.3 composite.
Skin sympathetic nerve activity as a biomarker for syncopal episodes during a tilt table test
(2020-05-01)
Kumar, Awaneesh
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Wright, Keith
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Uceda, Domingo E.
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Vasallo, Peter A., III
;
Rabin, Perry L.
BACKGROUND Autonomic imbalance is the proposed mechanism of syncope during a tilt table test (TTT). We have recently demonstrated that skin sympathetic nerve activity (SKNA) can be noninvasively recorded using electrocardiographic electrodes. OBJECTIVE The purpose of this study was to test the hypothesis that increased SKNA activation precedes tilt-induced syncope. METHODS We studied 50 patients with a history of neurocardiogenic syncope undergoing a TTT. The recorded signals were band-pass filtered at 500-1000 Hz to analyze nerve activity. RESULTS The average SKNA (aSKNA) value at baseline was 1.38 +/- 0.38 mu V in patients without syncope and 1.42 +/- 0.52 mu V in patients with syncope (P = .77). On upright tilt, aSKNA was 1.34 +/- 0.40 mu V in patients who did not have syncope and 1.39 +/- 0.43 mu V in patients who had syncope (P = .65). In all 14 patients with syncope, there was a surge of SKNA before an initial increase in heart rate followed by bradycardia, hypotension, and syncope. The peak aSKNA immediately (<1 minute) before syncope was significantly higher than baseline aSKNA (2.63 +/- 1.22 vs 1.39 +/- 0.43 mu V; P = .0005). After syncope, patients were immediately placed in the supine position and aSKNA dropped significantly to 1.26 +/- 0.43 mu V; (P = .0004). The heart rate variability during the TTT shows a significant increase in parasympathetic tone during syncope (low-frequency/high-frequency ratio: 7.15 vs 2.21; P = .04). CONCLUSION Patients with syncope do not have elevated sympathetic tone at baseline or during the TTT except immediately before syncope when there is a transient surge of SKNA followed by sympathetic withdrawal along with parasympathetic surge.
水一分殊、界分江河：漢語東南方言水系通名使用之歷史層次與空間意涵
(國立交通大學客家文化學院, 2020-05)
程俊源
;
韋煙灶
;
Chun-yuan Cheng
;
Yen-tsao Wei
地理語言學時能觀察詞彙的地理空間分布，藉以說明語言社群相互間的此疆彼界。本文從漢語東南方言水系通名使用的角度進入議題，融合地理學、語言學與歷史學的科際整合研究途徑，考察吳、閩、粵、客、贛、徽、湘等方言族群中的水系通名使用狀況，針對江、河、溪、川、水、港、坑……等語源進行討論，並探究這些河流通名在臺、閩、粵之閩語區與客語區的空間分布特色及其形成之因果關係，提出學理與文獻的論證。
Nucleate Pool Boiling Heat Transfer from High-Flux Tube with Dielectric Fluid HFE-7200
(2020-05-01)
Kumar, Abhishek
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Hung, Kuo-Shu
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Wang, Chi-Chuan
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機械工程學系
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Department of Mechanical Engineering
In the present experimental study, nucleate pool boiling heat transfer measurements of two high-flux tubes (sample A and sample B) were conducted at atmospheric pressure with HFE-7200 as the working fluid. Both high-flux tubes were made from a sintered Cu-Ni (high-flux) alloy powder. The porous high-flux surface was coated inside the test tube and it is tested within the heat flux ranging from 2.6 to 86 kW/m(2). The major difference between sample A and sample B was the coating thickness, where sample B (0.6 mm) was much larger than that of sample A (0.07 mm). Both tubes showed about three times enhancement in heat transfer coefficient (HTC) when compared to plain tube. Even though sample B contained a higher HTC than sample A, it also revealed a faster level-off phenomenon regarding the HTC vs. wall superheat. The major parameter which characterizes the boiling performance of high-flux tube was the ratio of coating thickness to pore diameter which also yielded different trends upon HTC vs. wall superheat amid sample A and B. It was found that the porous based Nishikawa correlation can well predict the performance of sample A but not sample B. This is because the ratio of coating thickness to pore diameter is far outside the applicable range of the Nishikawa correlation. Hence, a modified Nishikawa correlation is proposed. The predicted capability of the proposed modified Nishikawa correlation against sample A and sample for HTC was within +/- 28% deviation. The standard mean deviation of the Nishikawa correlation with experimental data for sample A and sample B was 0.302 (12.48%) and 5.64 (73%), respectively.
全球政經變局下的苗栗客庄：土地、開發與地方重構
(國立交通大學客家文化學院, 2020-05)
傅偉哲
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林辰
;
Weiche Fu
;
Chen Lin
本文主張全球政治經濟轉變下的產業變遷，是解釋晚近苗栗北部客庄—竹南、頭份—地方重構的主要原因。1990與2000年代中期，苗栗的竹南、頭份在新興產業的擴張與既有產業外移下，地方政府與政治、經濟菁英，運用土地開發創造了以「土地」為資本積累核心的經濟活動；這一經濟活動，雖然造就短期繁榮，但卻也帶來產業結構變遷、所得分配變化，以及地方金融與財政債務化的風險與挑戰。在全球政經變遷驅動地方社會重構之際，本文也主張，苗栗因其地緣發展的時間與空間相對延遲位置，造就台灣戰後第二大客家聚落形成獨特經濟發展模式；這種模式正為既有客家族群聚落帶來嚴峻的衝擊。
Big Data Platform Configuration Using Machine Learning
(2020-05-01)
Yeh, Chao-Chun
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Lu, Han-Lin
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Zhou, Jiazheng
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Chang, Sheng-An
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Lin, Xuan-Yi
By ensuring well-developed complex big data platform architectures, data engineers provide data scientists and analysts infrastructure with computational and storage resources to perform their research. Based on such supports, data scientists are provided an opportunity to focus on their domain problems and design the required intelligent modules (i.e., prepare the data; select, train, and tune the machine-learning modules; and validate the results). However, there are still gaps between system engineering and data scientist/engineering teams. Generally, system engineers have limited knowledge on the application domains and the purposes of an analytical program. On the contrary, both data scientists and engineers are usually unfamiliar with the configuration of a computational system, file system, and database. However, the performance of an application can be affected by a system's configuration, and the data scientists and engineers have little information and knowledge about which of the system's properties can affect the application's performance. As a typical example, for Internet-scale applications that have thousands of computing nodes or billions of Internet of Things devices, even a slight improvement may have an enormous influence on energy management and environmental protection issues. To bridge the gap between system engineering and data scientist/engineering teams, we proposed the concept of a configuration layer based on a big data platform, Hadoop. We built a configuration tuner, BigExplorer, to collect and preprocess data. Furthermore, we also created golden configurations for performance improvement. Based on the processed data, we used a semi-automatic feature engineering technique to provide more features for data engineers and developed the performance model using three different machine learning algorithms (i.e., random forest, gradient boosting machine, and support vector machine). Using the commonly used benchmarks of Word-Count, TeraSort, and Pig workloads, our configuration tuner achieved a significant performance improvement of 28%-51% for different workloads than using the rule-of-thumb configuration.
Improved Color Purity of Monolithic Full Color Micro-LEDs Using Distributed Bragg Reflector and Blue Light Absorption Material
(2020-05-01)
Chu, Shao-Yu
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Wang, Hung-Yu
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Lee, Ching-Ting
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Lee, Hsin-Ying
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Laing, Kai-Ling
In this study, CdSe/ZnS core-shell quantum dots (QDs) with various dimensions were used as the color conversion materials. QDs with dimensions of 3 nm and 5 nm were excited by gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with a size of 30 mu m x 30 mu m to respectively form the green and red lights. The hybrid Bragg reflector (HBR) with high reflectivity at the regions of the blue, green, and red lights was fabricated on the bottom side of the micro-LEDs to reflect the downward light. This could enhance the intensity of the green and red lights for the green and red QDs/micro-LEDs to 11% and 10%. The distributed Bragg reflector (DBR) was fabricated on the QDs color conversion layers to reflect the non-absorbed blue light that was not absorbed by the QDs, which could increase the probability of the QDs excited by the reflected blue light. The blue light absorption material was deposited on the DBR to absorb the blue light that escaped from the DBR, which could enhance the color purity of the resulting green and red QDs/micro-LEDs to 90.9% and 90.3%, respectively.
Pilot-scale ozone/biological activated carbon treatment of reverse osmosis concentrate: potential for synergism between nitrate and contaminant removal and potable reuse
(2020-05-01)
Zhang, Zhong
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King, Jacob F.
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Szczuka, Aleksandra
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Chuang, Yi-Hsueh
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Mitch, William A.
With limited budgets, utilities may forego potable reuse of municipal wastewater to meet regulations requiring nitrate and contaminant removal from discharges. At 85% recovery, reverse osmosis (RO)-based potable reuse rejects contaminants into a concentrate flowrate that is 6.7-fold lower than wastewater discharges. This study evaluated the footprint and cost savings associated with treating nitrate and contaminants in RO concentrate vs. wastewater effluent. Pilot-scale ozone and biological activated carbon (BAC) treatment of RO concentrate provided design parameters needed for this comparison. Addition of 60 mg C per L methanol as a carbon source was needed to achieve complete denitrification of 70 mg N per L nitrate within a 30 min BAC empty bed contact time. Combined with pre-ozonation at 0.5 mg O-3/mg DOC, this treatment removed >74% of fipronil, imidacloprid, atenolol, DEET and sulfamethoxazole. Estimates indicated that applying ozone/BAC treatment to RO concentrate rather than conventional wastewater effluent for contaminant removal prior to discharge would offset 60% of the footprint and 25% of the cost required for the RO-based potable reuse train. Considering these savings, the reuse train cost could be recouped if the product water were sold at rates below those current in southern California. These results suggest synergy rather than competition between potable reuse and contaminant removal.
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance
(2020-05-01)
Sun, Ching-Cherng
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Lin, Yi-Syuan
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Yang, Tsung-Hsun
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Lin, Shih-Kang
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Lee, Xuan-Hao
A luminaire with a light-emitting diode (LED) array can provide hotspot illumination in a short range. Therefore, a design of a luminaire with the largest central illuminance (LCI) and a high uniformity is warranted. In this paper, we present a study of illuminance variation with respect to the distance of an illumination target of a luminaire with LED array. The emission property of the luminous intensity is characterized by the cosine power law or the divergent angle of full width at half maximum (FWHM). A real LED module is designed to create the simulation for different luminaire types. The occurrence of the LCI and the far-field region are observed. Our results demonstrate that the LCI distance remains shorter than the starting distance of the far field (SDFF). To simplify the simulation, we propose the replacement of the real LED module with a point or flat-extended source. Such light sources must be equipped with the specific cosine power factor corresponding to the divergent angle of the FWHM of the LED module. These light sources are acceptable for describing illumination characteristics, including the SDFF. Our results may facilitate the design of LED-array luminaires operated at short working distances, such as reading lighting or illumination in microscopes.
當史學遇到客家：解構後的重新認識
(國立交通大學客家文化學院, 2020-05)
林正慧
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Cheng-hui Lin
就歷史研究而言，史料文獻是立論的重要基石；而以後見之明來看，客家是晚近才形成的概念。但臺灣在戰後展開客家研究時，已普遍存在客家有著悠久的中原南遷歷史的成說。隨著研究的愈加深入，卻在歷史文獻中找不到客家，於是開始反思何謂客家，進而重新認識客家。本文擬以自身研究客家歷史的經驗，參照既有研究成果，觀察臺灣在戰後以來，以史學方法研究客家的歷程中，如何將由不同成說所堆砌的客家樣貌予以解構後，再重新認識的過程。史學反思客家的過程，同時見證了社會科學的邊緣理論、建構理論等在歷史上真實發生的過程。那些族源論述不能直接視為歷史事實，必須回到發生的時空脈絡，理清其形成的經過，才可能還原歷史的事實。因此，就客家研究而言，史學除了固守對史料的重視之外，已難閉門造車，必須多方與其他學科溝通對話，才能探究出比較真確的客家歷史。
Melanin production as a visual indicator of conjugal transfer in Streptomyces
(2020-05-01)
Chen, Ting-wen
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Chen, Carton W.
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生物資訊及系統生物研究所
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Institude of Bioinformatics and Systems Biology
To visualize transfer of plasmid in Streptomyces during conjugation, we constructed a conjugative plasmid that harbored melC operon encoding an extracellular tyrosinase and placed it in Streptomyces hosts which were defective in expressing the operon. Hyphae of these donors were mixed with hyphae of a plasmidless recipient, which could express melC, and plated on a solid medium supplemented with tyrosine. After 8 to 9 h of incubation, melanin started to appear in the mating mixture, indicating that the plasmid had entered the recipient and started to synthesize tyrosinase, which in turn catalyzed the formation of melanin. This visual monitoring system allows quick demonstration of conjugal transfer without tedious genetic or biochemical procedure commonly used. It may be applied to most Streptomyces species and may also be used for monitoring chromosome transfer.
Improved Charge Pump Design and Ex Vivo Experimental Validation of CMOS 256-Pixel Photovoltaic-Powered Subretinal Prosthetic Chip
(2020-05-01)
Kuo, Po-Han
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Wong, Oi-Ying
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Tzeng, Chi-Kuan
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Wu, Pu-Wei
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Chiao, Chuan-Chin
An improved design of CMOS 256-pixel photovoltaic-powered implantable chip for subretinal prostheses is presented. In the proposed subretinal chip, a high-efficiency fully-integrated 4x charge pump is designed and integrated with on-chip photovoltaic (PV) cells and a 256-pixel array with active pixel sensors (APS) for image light sensing, biphasic constant current stimulators, and electrodes. Thus the PV voltage generated by infrared (IR) light can be boosted to above 1V so that the charge injection is increased. The proposed chip adopts the 32-phase divisional power supply scheme (DPSS) to reduce the required supply current and thus the required area of the PV cells. The proposed chip is designed and fabricated in 180-nm CMOS image sensor (CIS) technology and post-processed with biocompatible IrOx electrodes and silicone packaging. From the electrical measurement results, the measured stimulation frequency is 28.3 Hz under the equivalent electrode impedance load. The measured maximum output stimulation current is 7.1 mu A and the amount of injected charges per pixel is 7.36 nC under image light intensity of 3200 lux and IR light intensity of 100 mW/cm(2). The function of the proposed chip has been further validated successfully with the ex vivo experimental results by recording the electrophysiological responses of retinal ganglion cells (RGCs) of retinas from retinal degeneration (rd1) mice with a multi-electrode array (MEA). The measured average threshold injected charge is about 3.97 nC which is consistent with that obtained from the patch clamp recording on retinas from wild type (C57BL/6) mice with a single electrode pair.
KSCN-activation of hydrogenated NiO/TiO2 for enhanced photocatalytic hydrogen evolution
(2020-05-01)
Wang, Tsai-Te
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Chiang, Chao-Lung
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Lin, Yu-Chang
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Srinivasadesikan, Venkatesan
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Lin, Ming-Chang
It was investigated the efficiency of hydrogen production from NiO-loaded TiO2 treated by methanol hydrogenation and functionalized by SCN ligand (SCN-M:(NiO/TiO2)). The effects of a p-n junction created between NiO and TiO2 were demonstrated to enhance significantly the overall photocatalytic performance. The optical and microstructural properties of SCN-M:(NiO/TiO2) were studied with ultraviolet-visible spectra (UV-Vis), photoluminescence (PL), Raman spectra, X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). The atomic and electronic configurations of SCN-M:(NiO/TiO2) were investigated with analysis of the X-ray absorption near-edge structure (XAS) in situ under irradiation with Xe lamp incorporating a filter (AM 1.5G). An effective quantum yield of 1.34% for hydrogen production was attained with SCN-M:(NiO/TiO2). Quantum-chemical calculations revealed a synergistic decrease of the band gap upon loading Ni, Ni-linked O-2 and anionic SCN-ligand binding. The optimal energy bandgap was decreased to 2.70 eV for (SCN/O-2)-3Ni@TiO2, which reasonably supported the enhancement of H-2 evolution.
An exact method for constrained maximization of the conditional value-at-risk of a class of stochastic submodular functions
(2020-05-01)
Wu, Hao-Hsiang
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Kucukyavuz, Simge
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管理科學系
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Department of Management Science
We consider a class of risk-averse submodular maximization problems (RASM) where the objective is the conditional value-at-risk (CVaR) of a random nondecreasing submodular function at a given risk level. We propose valid inequalities and an exact general method for solving RASM under the assumption that we have an efficient oracle that computes the CVaR of the random function. We demonstrate the proposed method on a stochastic set covering problem that admits an efficient CVaR oracle for the random coverage function. (C) 2020 Elsevier B.V. All rights reserved.
Integrated airline productivity performance evaluation with CO2 emissions and flight delays
(2020-05-01)
Huang, Fei
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Zhou, Dequn
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Hu, Jin-Li
;
Wang, Qunwei
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經營管理研究所
This paper evaluates the airline productivity change by applying a modified global Malmquist productivity index (GMPI) model, incorporating both CO2 emissions and flight delays. Statistical inference is also performed on the GMPI results using the bootstrapping method. Empirical research was conducted on 15 international airlines during 2011-2017. The obtained results showed that the productivity of all airlines had been fluctuating and experienced a slight increase over 2011-2017. Most of these 15 airlines made more progress in managing punctuality than CO2 emissions. High punctuality policy may not be the best choice for all airlines when considering financial constraints, while airlines in more liberalized aviation markets are more likely to improve productivity by reducing flight delays. Efficiency change and technological change were the major driving factors for the growth of airline productivity. European and US airlines benefitted more from superior technology, while most Asian and Oceanian airlines still benefitted from the advantage of efficiency. Based on the findings, specific management advice was given.
Growth, transfer printing and colour conversion techniques towards full-colour micro-LED display
(2020-05-01)
Zhou, Xiaojie
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Tian, Pengfei
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Sher, Chin-Wei
;
Wu, Jiang
;
Liu, Hezhuang
Micro light-emitting diode (micro-LED) display, mainly based on inorganic GaN-based LED, is an emerging technique with high contrast, low power consumption, long lifetime and fast response time compared to liquid crystal display (LCD) and organic light-emitting diode (OLED) display. Therefore, many research institutes and companies have conducted in-depth research on micro-LED in the full-colour display, gradually realizing the commercialization of micro-LED. And the current research results of micro-LED indicate that it can be widely used in display, visible light communication (VLC), biomedicine and other fields. Although micro-LED has broad commercial prospects, it still faces great challenges, such as the effect of size reduction on performance, the realization of high-density integration on a single wafer for independent addressing of full-colour micro-LED display, the improvement of repair technique and yield a al. This paper reviews the key solutions to the technical difficulties of the full-colour micro-LED display. Specifically, this review analyzes and discusses a variety of advanced full-colour micro-LED display techniques with a focus on three aspects: growth technique, transfer printing technique and colour conversion technique. This review demonstrates the opportunities, progress and challenges of these techniques, aiming to guide the development of full-colour micro-LED display.