Browsing by Issue Date, starting with "2019-06-10"

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Flexible light valves using polymer-dispersed liquid crystals and TiO2/Ag/TiO2 multilayers
(2019-06-10)
Chiou, Chung Chin
;
Hsu, Fan Hsi
;
Petrov, Stefan
;
Marinova, Vera
;
Dikov, Hristosko
The era of flexible optoelectronics demands development of wearable and bendable structures, foldable touch screens, paper-like displays, and curved and flexible solid-state lighting devices. Here, we demonstrate the fabrication of highly flexible light valves using polymer-dispersed liquid crystal (PDLC) and TiO2/Ag/TiO2 transparent conductive films. TiO2/Ag/TiO2 multilayers were prepared by magnetron sputtering technique on polyethylene terephthalate (PET) substrates at room temperature. By keeping the equivalent TiO2 layers and varying the deposition time of the Ag layer, proper metal nanograins on TiO2 planar plane were formed, providing the best tradeoff between the transmittance, sheet resistance and bending ability. The results are validated by numerical simulations that suggest the best match between the deposition time and individual layer thickness. Based on the performed characteristics of TiO2/Ag/TiO2/PET structures, several flexible light valves are fabricated and characterized. The sheet resistance values of TiO2/Ag/TiO2/PET remain unchanged over 1000 bending cycles. The measured driving voltage and response time values open great potential of TiO2/Ag/TiO2/PET for integration into next-generation ITO-free flexible and stretchable devices. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Protein-protein interaction prediction using a hybrid feature representation and a stacked generalization scheme
(2019-06-10)
Chen, Kuan-Hsi
;
Wang, Tsai-Feng
;
Hu, Yuh-Jyh
;
交大名義發表
;
分子醫學與生物工程研究所
BackgroundAlthough various machine learning-based predictors have been developed for estimating protein-protein interactions, their performances vary with dataset and species, and are affected by two primary aspects: choice of learning algorithm, and the representation of protein pairs. To improve the performance of predicting protein-protein interactions, we exploit the synergy of multiple learning algorithms, and utilize the expressiveness of different protein-pair features.ResultsWe developed a stacked generalization scheme that integrates five learning algorithms. We also designed three types of protein-pair features based on the physicochemical properties of amino acids, gene ontology annotations, and interaction network topologies. When tested on 19 published datasets collected from eight species, the proposed approach achieved a significantly higher or comparable overall performance, compared with seven competitive predictors.ConclusionWe introduced an ensemble learning approach for PPI prediction that integrated multiple learning algorithms and different protein-pair representations. The extensive comparisons with other state-of-the-art prediction tools demonstrated the feasibility and superiority of the proposed method.
Memristor effect in GeO[SiO2] and GeO[SiO] solid alloys films
(2019-06-10)
Volodin, V. A.
;
Kamaev, G. N.
;
Gritsenko, V. A.
;
Gismatulin, A. A.
;
Chin, A.
The p-Si(or n-Si)/GeO[SiO2] (or GeO[SiO])/indium-tin-oxide (ITO) structures were fabricated by simultaneous evaporation of GeO2 and SiO2 (or SiO) powders in high vacuum and further deposition of ITO contacts using the magnetron sputtering technique. The structural properties of the GeO[SiO2] and GeO[SiO] films were studied using FTIR and Raman spectroscopy. According to Raman data, the GeO[SiO] films deposited at a temperature of 100 degrees C contain amorphous Ge clusters. Their current-voltage characteristics were measured in the air atmosphere, and resistive switching (memristor effect) was observed in structures without a preliminary forming procedure. The Shklovskii-Efros percolation model gives a consistent explanation for the charge transport in the high-resistive state and the low-resistive state of memristors based on GeO[SiO2] or GeO[SiO] films.
Characterization of the charge density wave transition and observation of the amplitude mode in LaAuSb2
(2019-06-10)
Kuo, C. N.
;
Shen, D.
;
Li, B. S.
;
Nguyen Nhat Quyen
;
Tzeng, W. Y.
In order to elucidate the charge density wave (CDW) nature in LaAuSb2, we have carried out the electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, as well as ultrafast pump-probe spectroscopy measurements on single crystalline LaAuSb2. The CDW phase transition has been characterized by marked features near T-C similar or equal to 88 K. In particular, the obtained Hall carrier concentration and electronic thermal conductivity exhibit significant reduction as T-C drops, providing strong evidence for partial gapping of the Fermi surfaces during the CDW phase transition. Furthermore, the ultrafast pump-probe spectroscopy reveals pronounced oscillatory features in the photoinduced transient reflectivity in the CDW ordered state. A characteristic oscillation mode with frequency of about 0.32 THz was extracted. The comparison of the obtained oscillation frequency with the frequencies of the amplitude mode in the well-studied CDW analogue LaAgSb2 allows us to ascribe the observation to the amplitude mode of CDW collective excitations in LaAuSb2.
Impact of the surface recombination on InGaN/GaN-based blue micro-light emitting diodes
(2019-06-10)
Kou, Jianquan
;
Shen, Chih-Chiang
;
Shao, Hua
;
Che, Jiamang
;
Hou, Xu
In this work, the size-dependent effect for InGaN/GaN-based blue micro-light emitting diodes (mu LEDs) is numerically investigated. Our results show that the external quantum efficiency (EQE) and the optical power density drop drastically as the device size decreases when sidewall defects are induced. The observations are owing to the higher surface-to-volume ratio for small mu LEDs, which makes the Shockley-Read-Hall (SRH) non-radiative recombination at the sidewall defects not negligible. The sidewall defects also severely affect the injection capability for electrons and holes, such that the electrons and holes are captured by sidewall defects for the SRH recombination. Thus, the poor carrier injection shall be deemed as a challenge for achieving high-brightness mu LEDs. Our studies also indicate that the sidewall defects form current leakage channels, and this is reflected by the current density-voltage characteristics. However, the improved current spreading effect can be obtained when the chip size decreases. The better current spreading effect takes account for the reduced forward voltage. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
A metafrontier pollution efficiency analysis of Taiwan's administrative regions
(2019-06-10)
Chang, Ming-Chung
;
Hu, Jin-Li
;
Chen, Ching-Hsin
;
經營管理研究所
;
Institute of Business and Management
This study proposes a two-stage approach to perform metafrontier analysis of the pollution efficiency of administrative regions in Taiwan during 2004-2015. The empirical research shows that New Taipei City and Taipei City have the best performances in terms of metafrontier efficiency and the technology gap ratio. In addition, the average score for pollution efficiency in municipalities is higher than that in non municipalities for three environmental management indices. However, the metropolitan and non metropolitan regions face different environmental problems in that the former should pay attention to sewage treatment, while the latter should focus attention on preventing air pollution. Finally, Taiwan presents disparity in the environmental technology gap ratio between these two types of regions. (C) 2019 Elsevier Ltd. All rights reserved.
Application of a two-dimensional Butler matrix antenna array for tile-based beamforming
(2019-06-10)
Hsieh, Cheng-Hung
;
Lin, Yi-Ting
;
Jhan, Hsaing-Chieh
;
Tsai, Zuo-Min
;
電機工程學系
This paper proposes a new two-dimensional (2D) Butler matrix antenna array with 16 switching beams for tile-based beamforming. This study fabricated and assembled a 3.5-GHz Butler switching antenna array using multilayer Rogers printed circuit board technology. It adopted a new design concept and layer-by-layer vertical connection architecture. This 2D Butler matrix antenna array does not require long coaxial cables to connect functional circuit interfaces, which is an improvement over the traditional Butler matrix beamforming network (BFN) antenna array and may facilitate considerable reductions in circuit volume and complexity.
Asymmetries in Porous Membranes: Fabrication of Anodic Aluminum Oxide Membranes with Double-Sized Nanopores and Controlled Surface Properties
(2019-06-13)
Liu, Chih-Ting
;
Lin, Yu-Liang
;
Chu, Chien-Wei
;
Chang, Chun-Wei
;
Chiu, Yu-Jing
Recently, anodic aluminum oxide (AAO) membranes with ordered and monodispersed nanopores have attracted significant attention because the pore sizes and lengths of the AAO membranes can be systematically controlled by changing the anodization parameters. Asymmetries of geometry, wettability, charge, and polarity in nanoporous AAO membranes are now highly desired for applications such as drug delivery, membrane filtration, and catalysis. Although the asymmetries in AAO membranes have been widely studied, AAO membranes whose nanopores simultaneously possess more than two asymmetric properties still need to be developed. In this work, we present a simple method to fabricate asymmetric AAO membranes by combining the post-treatments with the three-step anodization method. The asymmetries of the AAO membranes simultaneously possessing larger nanopores with higher hydrophobicity and smaller nanopores with lower hydrophobicity are characterized by scanning electron microscopy, water contact angle measurements, and energy-dispersive X-ray spectroscopy. Using the asymmetric AAO membranes, nanowires of polystyrene and poly(styreneb/ock-dimethylsiloxane) with double-sized diameters are also fabricated via the melt and solvent wetting methods, exhibiting that the AAO membranes with double-sized diameters can be used as the templates for generating double-sized polymer nanowires.
Cardiac characteristics and natural progression in Taiwanese patients with mucopolysaccharidosis III
(2019-06-13)
Lin, Hsiang-Yu
;
Chen, Ming-Ren
;
Lin, Shan-Miao
;
Hung, Chung-Lieh
;
Niu, Dau-Ming
BackgroundMucopolysaccharidosis type III (MPS III), or Sanfilippo syndrome, is caused by a deficiency in one of the four enzymes involved in the lysosomal degradation of heparan sulfate. Cardiac abnormalities have been observed in patients with all types of MPS except MPS IX, however few studies have focused on cardiac alterations in patients with MPS III.MethodsWe reviewed medical records, echocardiograms, and electrocardiograms of 26 Taiwanese patients with MPS III (five with IIIA, 20 with IIIB, and one with IIIC; 14 males and 12 females; median age, 7.4years; age range, 1.8-26.5years). The relationships between age and each echocardiographic parameter were analyzed.ResultsEchocardiographic examinations (n=26) revealed that 10 patients (38%) had valvular heart disease. Four (15%) and eight (31%) patients had valvular stenosis or regurgitation, respectively. The most prevalent cardiac valve abnormality was mitral regurgitation (31%), followed by aortic regurgitation (19%). However, most of the cases of valvular heart disease were mild. Three (12%), five (19%) and five (19%) patients had mitral valve prolapse, a thickened interventricular septum, and asymmetric septal hypertrophy, respectively. The severity of aortic regurgitation and the existence of valvular heart disease, aortic valve abnormalities and valvular stenosis were all positively correlated with increasing age (p<0.05). Z scores >2 were identified in 0, 38, 8, and 27% of left ventricular mass index, interventricular septal end-diastolic dimension, left ventricular posterior wall end-diastolic dimension, and aortic diameter, respectively. Electrocardiograms in 11 patients revealed the presence of sinus arrhythmia (n=3), sinus bradycardia (n=2), and sinus tachycardia (n=1). Six patients with MPS IIIB had follow-up echocardiographic data at 1.9-18.1years to compare with the baseline data, which showed some patients had increased thickness of the interventricular septum, as well as more patients had valvular abnormalities at follow-up.ConclusionsCardiac involvement in MPS III is less common and milder compared with other types of MPS. The existence of valvular heart disease, aortic valve abnormalities and valvular stenosis in the patients worsened with increasing age, reinforcing the concept of the progressive nature of this disease.
Enhancing thermoelectric performance by Fermi level tuning and thermal conductivity degradation in (Ge1-xBix)Te crystals
(2019-06-13)
Wei, Pai-Chun
;
Cai, Cheng-Xun
;
Hsing, Cheng-Rong
;
Wei, Ching-Ming
;
Yu, Shih-Hsun
In this work, a high thermoelectric figure of merit, zT of 1.9 at 740 K is achieved in Ge1-xBixTe crystals through the concurrent of Seebeck coefficient enhancement and thermal conductivity reduction with Bi dopants. The substitution of Bi for Ge not only compensates the superfluous hole carriers in pristine GeTe but also shifts the Fermi level (E-F) to an eligible region. Experimentally, with moderate 6-10% Bi dopants, the carrier concentration is drastically decreased from 8.7 x 10(20) cm(-3) to 3-5 x 10(20) cm(-3) and the Seebeck coefficient is boosted three times to 75 mu VK-1. In the meantime, based on the density functional theory (DFT) calculation, the Fermi level E-F starts to intersect with the pudding mold band at L point, where the band effective mass is enhanced. The enhanced Seebeck coefficient effectively compensates the decrease of electrical conductivity and thus successfully maintain the power factor as large as or even superior than that of the pristine GeTe. In addition, the Bi doping significantly reduces both thermal conductivities of carriers and lattices to an extremely low limit of 1.57W m(-1)K(-1) at 740 K with 10% Bi dopants, which is an about 63% reduction as compared with that of pristine GeTe. The elevated figure of merit observed in Ge1-xBixTe specimens is therefore realized by synergistically optimizing the power factor and downgrading the thermal conductivity of alloying effect and lattice anharmonicity caused by Bi doping.
傑出校友連加恩勉勵學弟妹：台灣需要像海盜的人才
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組
即將進入六月畢業季，在非洲行醫多年的連加恩校友，5月28日應陽明國際衛生學程邀請回到台灣。在對全校的演講中，他勉勵學生要當一...
【孟德爾之夢：遺傳的百年探索】展覽
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組
【2019醫藥發展暨新知研討會】
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組
【科創講堂 Tech-Talk FORUM 2019】智慧醫療
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組
首度參加龍舟競賽，陽明一戰成名
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組
陽明今年首度組隊參加「北投洲美龍舟競渡」，便締造出2分14秒73的佳績，在28支隊伍中名列第四。初次成軍就身手不凡，擊敗眾多隊伍...
Ex-situ soft X-ray absorption spectroscopic investigation of NiCo2O4 annealed in different gases for hydrogen generation by electrolysis of urea
(2019-06-14)
Chang, Han-Wei
;
Dong, Chung-Li
;
Lu, Ying-Rui
;
Huang, Yu-Cheng
;
Chen, Chi-Liang
Electrochemical and ex-situ X-ray absorption spectroscopic (XAS) measurements of NiCo2O4 that have been annealed in different gases (Ar and air) were made to evaluate the efficiency of its electrocatalysis of hydrogen generation by the electrolysis of urea. The electrochemical and XAS measurements demonstrated that NCO-Ar contain significant amounts of Co2+ in octahedral coordination was more favorable than NCO-air for urea electrolysis owing to the effective exposure of electrochemical active sites to participate in the Faradic redox reaction. Further insight into the electrocatalytic mechanism of NiCo2O4-based materials during urea electrolysis was obtained using ex-situ soft XAS. The results of ex-situ soft XAS revealed that the variation of the octahedral and tetrahedral coordinations of Co2+ in NCO-Ar and NCO-air importantly contributes to electrocatalytic behavior. NCO-Ar exhibits excellent electrocatalytic activity towards the Co redox couples in a repetitive cycling process owing to the creation of highly efficient active sites (octahedral Co2+). This study presents importantly x-ray spectroscopic determination of the change in electronic structure of catalyst for hydrogen production. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
《異星入境》（Arrival）
(國立陽明大學, 2019-06-14)
黃柏威
;
陽明電子報編輯小組
Ni and Pd N-confused porphyrin complexes as catalysts for the synthesis of cyclic carbonates from epoxides and CO2
(2019-06-14)
dela Cruz, Jay-ar B.
;
Ruamps, Mirko
;
Arco, Susan
;
Hung, Chen-Hsiung
;
應用化學系
We have demonstrated the design of a novel bifunctional catalyst that is based on an N-confused tetraphenylporphyrin (NCTPP) motif for the cycloaddition of an epoxide to carbon dioxide via cooperative activation of the epoxide through a Pd(II) or Ni(II) metal center and a peripheral benzoate moiety with percent conversions of up to 99% and TON = 7000.
【讀風──張曉風特展】
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組
【解剖所專題演講】
(國立陽明大學, 2019-06-14)
陽明電子報編輯小組