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

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Improving Interface State Density and Thermal Stability of High-kappa Gate Stack Through High-Vacuum Annealing on Si0.5Ge0.5
(2019-05-01)
Lee, Wei-Li
;
Yu, Cheng-Yu
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Zhang, Jun-Lin
;
Luo, Guang-Li
;
Chien, Chao-Hsin
We fabricated HfO2-based gate stacks on epi-Si0.5Ge0.5 substrates and investigated the effect of thermal treatment on their structural and electrical properties at varying temperatures and pressures in oxygen ambient. The thermal treatment process led to severe degradation of interface quality as the temperature increased. Material analyses indicated that annealing in oxygen ambient resulted in oxygen diffusion from the high-k material to the SiGe surface, causing undesirable SiGe reoxidation. In high-vacuum annealing, an interface state density of approximately 1.4 x 10(11) eV(-1) cm(-2) and a thermal stability of up to 500 degrees C were achieved for the gate stack on SiGe.
Motivations, Usage, and Perceived Social Networks Within and Beyond Social Media
(2019-05-01)
Lai, Chih-Hui
;
傳播與科技學系
;
Department of Communication and Technology
This study addresses the questions of how individuals use social media (SM) to build awareness of social networks (network perceptions) within and beyond SM, and how motivations and SM behaviors differentiate individuals' ability to build such awareness. The analysis of the 2017 Taiwan Communication Survey (TCS) identifies three types of users based on their motivations for SM use: omnivores, time-killers, and social-groomers, who are differentiated from one another in terms of different types of SM behaviors as well as perceived network structures on SM and beyond. For example, omnivores, who use SM for diverse purposes, tend to engage in SM browsing and reacting more than time-killers, who use SM to pass time. Compared to time-killers, social-groomers, those who use SM for social purposes, are more likely to perceive that they have a larger SM response network, a response network containing close ties, and that they have maintained diverse social relationships in the form of mixed-media relationships (MMRs). Moreover, SM posting is associated with the size and the diverse composition of the perceived response network on SM. More frequent SM posting is also associated with perceptions of having diverse social contacts maintained through MMRs, but such association depends on the size and composition of the perceived SM response network.
再現客家戲曲之風華：榮興客家採茶劇團
(國立交通大學客家文化學院, 2019-05)
鄭榮興
;
Rom-shing Cheng
這篇文章介紹榮興客家採茶劇團。
Synchronized multi-spot scanning strategies for the laser powder bed fusion process
(2019-05-01)
Tsai, Chun-Yu
;
Cheng, Chung-Wei
;
Lee, An-Chen
;
Tsai, Mi-Ching
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機械工程學系
The laser powder bed fusion (LPBF) process can produce parts with complex internal geometries that cannot be easily manufactured using a material removal process. However, owing to the different heat transfer efficiencies of a laser melting process, the optimal process parameters are limited to a small range. This study used galvanometric scanner technology and a diffractive optical element (DOE) to build an experimental multi-spot LPBF system. Adjustable characteristics were the angle and the lateral distance between spots. An adjustable multispot method was used to modulate the temperature field on the powder bed and enhance the processing quality and throughput. The results from the synchronized three-spot method using different scanning strategies improved the layer surface roughness Ra by 3.2 mu m. Moreover, the scanning time was decreased by 38.1% of the single-spot method.
Stretches across for chaos
(2019-05-01)
Li, Ming-Chia
;
應用數學系
;
Department of Applied Mathematics
In 2001, Kennedy et al. [Amer. Math. Mon. 108, 411-423 (2001) and Trans. Amer. Math. Soc. 353, 2513-2530 (2001)] showed a chaos lemma and stated the pseudoconjecture "stretches across implies existence of an invariant set." In this paper, we give a suitable definition of stretches across in topological sense so that the conjecture has an affirmative answer. More precisely, we show that there must be an orbit through a sequence of stretches across. In particular, a closed loop of stretches across implies existence of a periodic orbit. We also give the geometric meaning of stretches across and its relation with the global implicit function theorem.
On-line coupling of fizzy extraction with gas chromatography
(2019-05-01)
Yang, Hao-Chun
;
Urban, Pawel L.
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應用化學系
;
Department of Applied Chemistry
Fizzy extraction (FE) is carried out by first dissolving a carrier gas (typically, carbon dioxide) in a liquid sample at a moderate pressure (typically, 150kPa) and then rapidly depressurizing the sample. The depressurization leads to instant release of numerous microbubbles in the liquid matrix. The abruptly released gas extracts the volatile solutes and elutes them toward a detector in a short period of time. Here, we describe on-line coupling of FE with gas chromatography (GC). The two platforms are highly compatible and could be combined following several modifications of the interface and adjustments of the extraction sequence. The analytes are released within a short period of time (1.5s). Thus, the chromatographic peaks are satisfactorily narrow. There is no need to trap the extracted analytes in a loop or on a sorbent, as it is done in standard headspace and microextraction methods. The approach requires only minor sample pretreatment. The main parameters of the FE-GC-mass spectrometry (MS) method were optimized. The results of FE were compared with those of headspace flushing (scavenging headspace vapors), and the enhancement factors were in the order of 2 to 13 (for various analytes). The limits of detection for some of the tested analytes were lower in the proposed FE-GC-MS method than in FE combined with atmospheric pressure chemical ionization MS. The method was further tested in analyses of selected real samples (apple flavor milk, mixed fruit and vegetable juice drink, mango flavored drink, pineapple green tea, toothpaste, and yogurt).
Using numerical weather model outputs to forecast wind gusts during typhoons
(2019-05-01)
Yang, Tsun-Hua
;
Tsai, Chin-Cheng
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土木工程學系
;
Department of Civil Engineering
Numerical weather prediction (NWP) models are commonly used to predict mean wind speeds. However, methods for predicting gust wind speeds in NWP models are still lacking due to limitations of computer resources. This study develops two models to provide gust wind speed forecasts during a typhoon event (1) a linear regression-based model and (2) a micro-genetic algorithm (MGA)-based model. This study also proposes a successively accumulated regression process that can adaptively update the parameters in the models and thereby improve the forecasts. The performance was evaluated by comparing observations from gauge stations in Taiwan during six typhoons that occurred between 2015 and 2016. The results of the models were compared to a statistical model from a previous study. The results showed that the successively accumulated regression process improves the mean error of the linear regression-based model to 5.23 m/s, compared with 7.08 m/s from the previous study. Meanwhile, the MGA-based model provides the best performance, with a 6.26 m/s time-averaged root mean squared errors for lead times of 7-54 h. This result is superior to the 9.37 m/s obtained with the statistics-based model and the 8.22 m/s obtained with the linear regression-based model.
Alkenylation and Allylation Reactions of Alkyl Halides Using Photo Catalyst
(2019-05-01)
Sumino, Shuhei
;
Ryu, Ilhyong
;
應用化學系
;
Department of Applied Chemistry
Radical addition/beta-fragmentation sequence has long been utilized for alkenylation and allylation of alkyl halides, in which key alkyl radicals are generated from alkyl halides by S(H)2 reaction typically using tributyltin radical. In this article, we describe modernized alkenylation and allylation of alkyl halides, in which alkyl radical generation is carried out by electron transfer under photoirradiation with the use of transition metal catalyst, which enables us to carry out the radical alkenylation and allylation without the use of radical initiators nor chain transfer reagents. Indeed, radical alkenylation of alkyl iodides using alkenyl bromides proceeded well by the use of a Pd/light combined system involving Hantzsch ester. Alkenyl and allyl sulfones worked better, since the system can obviate the use of Hantzsch ester. Mechanistically spontaneous reductive elimination of PhSO2I is suggested to recover the Pd catalyst. We also discuss allylation of gem-difluoromethylene-containing alkyl halides using allyl sulfones, which is best performed by the use of a visible light photoredox system based on Ru-catalyst.
Neuroimaging evidence for sensitivity to orthography-to-phonology conversion in native readers and foreign learners of Chinese
(2019-05-01)
Yu, Anya
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Chen, Makayla S. Y.
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Cherodath, Sarika
;
Hung, Daisy L.
;
Tzeng, Ovid J. L.
Through recent neuroimaging research into brain mechanisms of proficient reading and literacy acquisition in different languages, a common neural network supporting reading has been identified in native readers across various writing systems. However, whether the same or different brain regions are involved in learning to read a foreign language is largely unexplored. To investigate (1) neural correlates of literacy acquisition of Chinese in adults whose learning of this logographic language was relatively late, and (2) to examine which cognitive factors might be predictors of literacy acquisition that would modulate the computation demands on reading-related brain regions, native and non-native Chinese readers were recruited to participate in pronunciation and color verification tasks using Chinese pseudo-phonograms in fMRI while their sensitivity to extracting systematic regularity in nonverbal materials, as well as their IQ and working memory, was measured in a visual statistical learning (VSL) task. The results indicated that native participants activated a left lateralized reading network that is consistent with previous research on orthography-to-phonology conversion (OPC) of Chinese, while a similar but extensive network that also includes regions in the right hemisphere was engaged in the non-natives. Within this network, left inferior frontal sites were found to be crucial to the mapping of Chinese pseudo characters to potential sounds especially in non-natives. More important, only the VSL scores of native and non-native participants, but not their general cognitive abilities, were negatively correlated with the brain activities in the left inferior parietal and left inferior frontal regions, respectively, suggesting that the fundamental capacity of SL supports literacy acquisition through modulating computation demands on the brain regions associated with OPC processing, which is critical to Chinese character recognition.
A 183-GHz InP/CMOS-Hybrid Heterodyne-Spectrometer for Spaceborne Atmospheric Remote Sensing
(2019-05-01)
Kim, Yanghyo
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Zhang, Yan
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Reck, Theodore James
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Nemchick, Deacon J.
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Chattopadhyay, Goutam
Acomplete 183-GHz CMOS/Indium Phosphide (InP) hybrid heterodyne-spectrometer is realized for spaceborne atmospheric remote sensing applications. It captures spontaneous emission from thermally populated pure rotational states for investigating Earth/planetary atmosphere and interstellar media. Recent missions such as the heterodyne instrument for far-infrared, the microwave limb sounder, and the microwave instrument for Rosetta orbiter highlighted the wealth of scientific knowledge that can be attained by utilizing heterodyne-spectrometers. However, major challenges still remain in mission cost, instrument size, weight, and power (SWaP). Highly integrated CMOS circuits are designed to prototype a low-cost/SWaP spectrometer system and conduct challenging science missions. Within the prototype system, a 183-GHz receiver with a frequency synthesizer is designed in the 28-nm CMOS, and a back-end 6-GS/s 4096-point spectrometer processor is designed in the 65-nm CMOS. The receiver's center frequency is tunable from 180 to 200 GHz. An external InP low-noise amplifier is added at the front-end to provide the required receiver sensitivity. The demonstrated 28-nm CMOS receiver and 65-nm CMOS spectrometer consume 515 mW under 1.5/1.15-V and 1500 mW under 1 V supply, respectively. The complete system achieves 700 to 1000 K noise temperature within the interested bandwidth and RMS uncertainty improvement up to 10 s integration according to the Allan deviation measurements. The spectrometer's capability in detecting gas phase molecular compounds is verified with laboratory trials employing water (H2O) and methyl-cyanide (CH3CN).
Virtual titration laboratory experiment with differentiated instruction
(2019-05-01)
Wu, Bo-Jyun
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Wong, Sai-Keung
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Li, Ta-Wei
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應用化學系
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資訊工程學系
This paper studies users' learning perception in a virtual titration experiment with differentiated instruction. We develop a virtual reality chemistry lab and use leap motion to detect users' hand gestures for operations. Users wear a head-mounted display and use their bare hands to interact with virtual objects to perform a titration experiment. Our system implements a complete titration process and provides assistance tools for learning and operating virtual items. We report the essential ideas for building the system. We applied differentiated instruction to study the learning effectiveness of users under different learning intensities. Two groups of students with and without chemistry background participated in a user study. Our results indicated that the virtual reality chemistry lab could enhance and promote users' learning confidence under suitable learning intensities.
A 4.2 nW and 18 ppm/degrees C Temperature Coefficient Leakage-Based Square Root Compensation (LSRC) CMOS Voltage Reference
(2019-05-01)
Huang, Chao-Jen
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Lai, Yan-Jiun
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Yang, Yu-Jheng Ou
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Chen, Hung-Wei
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Kuo, Chun-Chieh
State-of-the-art CMOS-based voltage reference suffer from a trade-off between power dissipation and temperature coefficient (TC) due to the limited order of compensation in an advanced process which features a low supplied voltage (1 similar to 1.2 V). The proposed voltage reference with leakage-based square root compensation (LSRC) technique bias the substrate to offset TC with ultra-low leakage current (100 similar to 300 pA). On the other hand, the architecture provides an extensible order of compensation which is independent of voltage headroom. The two LSRC branches voltage reference implemented in 40 nm CMOS process achieves a within-wafer sigma/mu of 0.204 and a TC of 18 ppm/degrees C with a power consumption of 4.2 nW.
Redox fluctuations shape the soil microbiome in the hypoxic bioremediation of octachlorinated dibenzodioxin- and dibenzofuran-contaminated soil
(2019-05-01)
Wu, Jer-Horng
;
Chen, Wei-Yu
;
Kuo, Hung-Chih
;
Li, Yun-Ming
;
交大名義發表
The biodegradation of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs) has been recently demonstrated in a single reactor under hypoxic conditions. Maintaining hypoxic conditions through periodic aerations results in a marked fluctuation of reduction-oxidation (redox) potential. To further assess the effects of redox fluctuations, we operated two fed-batch continuously stirred tank reactors (CSTRs) with sophisticated redox controls at different anoxic/oxic fluctuations to reduce PCDD/Fs in contaminated soil. The results of long-term reactor operation showed that the CSTR with redox fluctuations at a narrow range (-63 +/- 68 mV) (CSTR_A) revealed a higher substrate hydrolysis level and PCDD/F degradation rate than did the CSTR with a redox potential that fluctuated at a broad range (-13 +/- 118 mV) (CSTR_B). In accordance with analyses of bacterial 16S rRNA genes, the designated hypoxic conditions with added compost supported survival of bacterial populations at a density of approximately 10(9) copies/g slurry. The evolved core microbiome was dominated by anoxic/oxic fluctuation-adapted Bacteroidetes, Alphaproteobacteria, and Actinobacteria, with higher species diversity and functionality, including hydrolysis and degradation of dioxin-like compounds in CSTR_A than in CSTR_B. Taken together, the overall results of this study expand the understanding of redox fluctuations in association with the degradation of recalcitrant substrates in soil and the corresponding microbiome. (C) 2019 Elsevier Ltd. All rights reserved.
Tunable Ge content and thickness in hemispherical-shell shaped SiGe recess channels created by proximal Ge nanospheres
(2019-05-01)
Chen, C. T.
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Peng, K. P.
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George, T.
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Lin, H. C.
;
Li, Pei-Wen
We report the novel tunability of Ge content, thickness, and even curvature/shape in self-aligned, hemispherical-shell shaped SiGe recess channels created in Si substrates by Ge nanospheres that are proximally located to these nanoshells. The hemispherical recess SiGe nanoshells arise from the migration of Ge interstitials through the intervening oxide layer between the Ge nanospheres and the Si substrate, and their Ge content, thickness, and curvatures exhibit a monotonic dependence on the depth of penetration of the Ge nanospheres into the Si substrate. Following a unique "explosion" phenomenon in which the Ge nanosphere breaks up into multiple nanocrystallites, both the Ge content and thickness of the SiGe nanoshells are significantly decreased by reverse migration of Ge interstitials from the SiGe nanoshells to the Ge nanocrystallites. (c) 2019 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Twisted Poincare series and zeta functions on finite quotients of buildings
(2019-05-01)
Kang, Ming-Hsuan
;
McCallum, Rupert
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應用數學系
;
Department of Applied Mathematics
In the case where G = SL2(F) for a non-archimedean local field F and Gamma is a discrete torsion-free cocompact subgroup of G, there is a known relationship between the Ihara zeta function for the quotient of the Bruhat-Tits tree of G by the action of Gamma, and an alternating product of determinants of twisted Poincare series for parabolic subgroups of the affine Weyl group of G. We show how this can be generalized to other split simple algebraic groups of rank two over F and formulate a conjecture about how this might be generalized to groups of higher rank.
A low-cost, portable and easy-operated salivary urea sensor for point-of-care application
(2019-05-01)
Wang, Kuan-Hsun
;
Hsieh, Ju-Chun
;
Chen, Chang-Chiang
;
Zan, Hsiao-Wen
;
Meng, Hsin-Fei
Salivary urea was reported to be a useful biomarker to reflect the blood urea nitrogen in chronic kidney disease patients. However, as a new biomarker, enormous clinical trials are required to define the intended-use and to verify the specification. In this report, we demonstrated a low-cost easy-operated real-time sensing system (optical fiber-urea-sensing, OFUS, system) to detect salivary urea. We aim to make the system easily reproduced by the community to stimulate abundant clinical tests worldwide. The OFUS system is composed of a simple three-dimensional printed tank to link with two optical fibers, one connecting with a commercial light-emitting diode to deliver the input light signal, the other connecting with a commercial cadmium sulfide photo-conductive cell to detect the sensing signal. To allow on-site detection without any sample pretreatment, only 1 mu l saliva is needed to be mixed with 10 mu l urease solution and 90 mu l pH indicator solution in the reaction tank and the detection time is only 20 s. A stable and reproducible calibration curve can be easily built with a detection range as 24-300 mg/dL. The OFUS system successfully detected saliva with added synthetic urea and samples from chronic kidney disease patients. A good agreement between the OFUS system and the commercial kit was obtained. A good correlation between salivary urea and the blood urea nitrogen was also confirmed.
Polypoid endometriosis - A rare entity of endometriosis mimicking ovarian cancer
(2019-05-01)
Tsai, Cleo
;
Huang, Shih-Hung
;
Huang, Chia-Yen
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生物科技學系
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Department of Biological Science and Technology
Objective: To report a rare case of polypoid endometriosis with initial impression of ovarian cancer and review the published literature about this disease. Case report: A 23-year-old female presented with sudden onset of acute lower abdominal pain. Image studies revealed an irregular shaped, heterogeneous mass at the cul-de-sac, but without ascites or enlargement of pelvic or paraaortic lymph nodes. Blood tests showed an elevated CA-125 value (1317 U/ ml). Resection of the mass was performed by laparotomy and the frozen section and final pathology both revealed polypoid endometriosis. Post-operative gonadotropin-releasing hormone agonist was given for 6 months followed by oral contraceptives. She remained disease free 3 years after operation. Conclusion: Polypoid endometriosis is an uncommon and distinctive variant of endometriosis. Gynecologists should be aware of this rare form of a commonly benign disease to avoid excessive resection in younger patients of childbearing age. (C) 2019 Taiwan Association of Obstetrics & Gynecology. Publishing services by Elsevier B.V.
Prostasin Impairs Epithelial Growth Factor Receptor Activation to Suppress Dengue Virus Propagation
(2019-05-01)
Lin, Chun-Kuang
;
Tseng, Chin-Kai
;
Wu, Yu-Hsuan
;
Lin, Chun-Yu
;
Huang, Chung-Hao
Background. Dengue virus (DENV), a common and widely spread arbovirus, causes life-threatening diseases, such as dengue hemorrhagic fever or dengue shock syndrome. There is currently no effective therapeutic or preventive treatment for DENV infection. Methods. Next-generation sequencing analysis revealed that prostasin expression was decreased upon DENV infection. Prostasin expression levels were confirmed by real-time quantitative polymerase chain reaction in patients with dengue fever and a DENV-infected mice model. Short hairpin RNA against EGFR and LY294002 were used to investigate the molecular mechanism. Results. Based on clinical studies, we first found relatively low expression of prostasin, a glycosylphosphatidyl inositol-anchored membrane protease, in blood samples from patients with dengue fever compared with healthy individuals and a high correlation of prostasin expression and DENV-2 RNA copy number. DENV infection significantly decreased prostasin RNA levels of in vivo and in vitro models. By contrast, exogenous expression of prostasin could protect ICR suckling mice from life-threatening DENV-2 infection. Mechanistic studies showed that inhibition of DENV propagation by prostasin was due to reducing expression of epithelial growth factor receptor, leading to suppression of the Akt/NF-kappa B-mediated cyclooxygenase-2 signaling pathway. Conclusion. Our results demonstrate that prostasin expression is a noteworthy clinical feature and a potential therapeutic target against DENV infection.
On the Accumulated Loopback Self-Interference of Two-Way Full-Duplex AF Relaying Systems
(2019-05-01)
Chang, Min-Kuan
;
Chien, Feng-Tsun
;
Kuo, Chih-Hung
;
Chen, Yen-Chang
;
交大名義發表
Two-way full-duplex (TWFD) transmissions in cooperative amplify-and-forward (AF) relaying systems provide a promising way of communications with the improved spectral efficiency by concurrently transmitting/receiving data in the same frequency band and by the two-way transmission protocol. However, the loopback self-interference, caused by the imperfect channel estimation in the loopback link, at the AF relay accumulates and is forwarded to the end users recurrently, which substantially degrades the end users' error performance if this accumulated loopback self-interference (ALSI) does not converge. It is therefore of critical importance to analyze the convergence behavior of the ALSI in the TWFD systems with AF relaying. In this paper, we establish sufficient conditions on the relay power to ensure the convergence of the ALSI, with which the average limiting signal-to-interference-plus-noise ratio at the infinite time horizon is derived. In addition, we specify the relay power at which the signal-to-noise ratio reaches the maximal value under different scenarios and obtain an upper bound to the symbol error rate. Finally, extensive computer simulations results are provided to corroborate the analytic derivations.
Risk of incident hypertension, diabetes, and dyslipidemia after first posttraumatic stress disorder diagnosis: A nationwide cohort study in Taiwan
(2019-05-01)
Lin, Ching-En
;
Chung, Chi-Hsiang
;
Chen, Li-Fen
;
You, Ching-Hui
;
Chien, Wu-Chien