Browsing by Issue Date, starting with "2019-06-21"

Now showing 1 - 20 of 7351

Correcting long-range electrostatics in DFTB
(2019-06-21)
Podeszwa, Rafal
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Jankiewicz, Wojciech
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Krzus, Magdalena
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Witek, Henryk A.
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交大名義發表
We demonstrate that the atom-based charge model implemented in the current versions of the density functional tight binding (DFTB) method fails to reproduce the correct charge distribution of a range of systems, including homonuclear molecules, graphene, and nanotubes, resulting in serious distortions in the electrostatic interactions for such systems caused by the missing quadrupole moments. In particular, this failure seriously impacts the long- and medium-range interaction energies of the DFTB plus dispersion (DFTB-D) model, leading to incorrect predictions of translational or rotational barriers in such systems. We show explicitly on examples of H-2 and N-2 that correct quadrupole momentsand consequently correct electrostatic interactionscan be restored in such systems by adding additional bond (ghost) sites to the homonuclear molecules. Attempts to determine the point charges associated with the additional sites using the usual Mulliken population analysis lead to unphysical results. Instead, these charges can be determined using the actual DFTB densities used in the parameterization process. For homonuclear molecules, we propose an extension to the DFTB-D model by adding charges that reproduce the physically correct quadrupolar charge distribution. The resulting DFTB-D-Q model greatly improves the rotational barriers for interactions of molecular hydrogen and nitrogen with benzene.
A functionalized membrane for lithium-oxygen batteries to suppress the shuttle effect of redox mediators
(2019-06-21)
Chen, Zi-Fang
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Lin, Xiaodong
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Xia, Hui
;
Hong, Yuhao
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Liu, Xiaoyu
Redox mediators (RMs) are widely applied in lithium-oxygen (Li-O-2) batteries since they offer an alternative way to avoid the direct electrochemical oxidization of Li2O2 during charging, and thus greatly reduce the charge overpotential. Unfortunately, the defenseless Li-metal anode is severely corroded by the oxidized RMs shuttled from the cathode side, resulting in the low utilization of RMs and poor cycling stability. Herein, a functionalized double-guaranteed NPG membrane with electrostatic repulsion and steric hindrance characteristics is proposed to suppress the shuttle effect of LiI RM. Benefiting from the interaction between the O atoms in PEO and the sulfonic acid groups in Nafion and the two-dimensional skeleton structure of graphene, Nafion, PEO and graphene can couple with each other, forming a large network barrier with multi-functional properties. As expected, the LiI-based Li-O-2 batteries with the NPG membrane exhibited a smooth, iodine-free Li anode surface after many cycles and delivered an ultrahigh discharge capacity of similar to 26 917 mA h g(-1) at a current density of 200 mA g(-1) and ultralong cycle life (472 cycles) at 500 mA g(-1) with a cutoff capacity of 500 mA h g(-1), which are far better than that of the bare batteries.
Direct generation of red and orange optical vortex beams from an off-axis diode-pumped Pr3+:YLF laser
(2019-06-24)
Ma, Yuanyuan
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Valles, Adam
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Tung, Jung-Chen
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Chen, Yung-Fu
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Miyamoto, Katsuhiko
We demonstrate the direct generation of visible vortex beams at 640 nm and 607 nm by employing an off-axis pumping scheme in a diode end-pumped Pr3+:YLF laser. A detailed numerical analysis, based on the coherent superposition of Hermite-Gaussian modes with different amplitudes and phases, is perfectly consistent with the experimentally observed lasing modes. The maximum vortex output powers have been measured to be 808 mW and 211 mW at a pump power of 3.16 W, for the wavelengths of 640 nm and 607 nm, respectively. We also demonstrate the handedness control of the generated vortex beam. Such a visible vortex laser can potentially be applied in super-resolution fluorescent microscopes and micro-fabrication research. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Electrochemical Properties of CNT/MnO2 Hybrid Nanostructure with Low-Temperature Hydrothermal Synthesis as High-Performance Supercapacitor
(2019-06-25)
Li, Wei-Shuo
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Chang, Man-Lin
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Chuang, Kai-Chi
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Li, Yi-Shao
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Luo, Jun-Dao
Multi-walled carbon nanotubes (CNTs)/manganese dioxide (MnO2) nanocomposites were fabricated using the low-temperature hydrothermal method with no oxidant addition as hybrid supercapacitors. The electrochemical behaviors of CNTs-MnO2 were systematically investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The specific capacitance was promoted from 30.3 F g(-1) to 405.15 F g(-1) with a hydrothermal reaction time of 5 min. Compared to pristine CNTs, the improvement ratio of the specific capacitance of a hydrothermal reaction time of 5 min was 13.4 times under the condition of a 1 M Na2SO4 electrolyte at a scan rate of 100 mVs(-1). The CNTs-MnO2 electrode also demonstrated better cycling stability after 1000 cycles. Moreover, this study demonstrates that CNTs-MnO2 electrodes have a low-temperature facile synthesis, high specific capacitance, and good cycle stability. Thus, these good supercapacitors electrodes are promising for the development in energy-storage devices in the future. (c) 2019 The Electrochemical Society.
SeQuery: an interactive graph database for visualizing the GPCR superfamily
(2019-06-25)
Hu, Geng-Ming
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Secario, M. K.
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Chen, Chi-Ming
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應用化學系
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Department of Applied Chemistry
The rate at which new protein and gene sequences are being discovered has grown explosively in the omics era, which has increasingly complicated the efficient characterization and analysis of their biological properties. In this study, we propose a web-based graphical database tool, SeQuery, for intuitively visualizing proteome/genome networks by integrating the sequential, structural and functional information of sequences. As a demonstration of our tool's effectiveness, we constructed a graph database of G protein-coupled receptor (GPCR) sequences by integrating data from the UniProt, GPCRdb and RCSB PDB databases. Our tool attempts to achieve two goals: (i) given the sequence of a query protein, correctly and efficiently identify whether the protein is a GPCR, and, if so, define its sequential and functional roles in the GPCR superfamily; and (ii) present a panoramic view of the GPCR superfamily and its network centralities that allows users to explore the superfamily at various resolutions. Such a bottom-up-to-top-down view can provide the users with a comprehensive understanding of the GPCR superfamily through interactive navigation of the graph database. A test of SeQuery with the GPCR2841 dataset shows that it correctly identifies 99 out of 100 queried protein sequences. The developed tool is readily applicable to other biological networks, and we aim to expand SeQuery by including additional biological databases in the near future.
A Novel AURKA Mutant-Induced Early-Onset Severe Hepatocarcinogenesis Greater than Wild-Type via Activating Different Pathways in Zebrafish
(2019-06-26)
Su, Zhong-Liang
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Su, Chien-Wei
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Huang, Yi-Luen
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Yang, Wan-Yu
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Sampurna, Bonifasius Putera
Aurora A kinase (AURKA) is an important regulator in mitotic progression and is overexpressed frequently in human cancers, including hepatocellular carcinoma (HCC). Many AURKA mutations were identified in cancer patients. Overexpressing wild-type Aurka developed a low incidence of hepatic tumors after long latency in mice. However, none of the AURKA mutant animal models have ever been described. The mechanism of mutant AURKA-mediated hepatocarcinogenesis is still unclear. A novel AURKA mutation with a.a.352 Valine to Isoleucine (V352I) was identified from clinical specimens. By using liver-specific transgenic fish overexpressing both the mutant and wild-type AURKA, the AURKA(V352I)-induced hepatocarcinogenesis was earlier and much more severe than wild-type AURKA. Although an increase of the expression of lipogenic enzyme and lipogenic factor was observed in both AURKA(V352I) and AURKA(WT) transgenic fish, AURKA(V352I) has a greater probability to promote fibrosis at 3 months compared to AURKA(WT). Furthermore, the expression levels of cell cycle/proliferation markers were higher in the AURKA(V352I) mutant than AURKA(WT) in transgenic fish, implying that the AURKA(V352I) mutant may accelerate HCC progression. Moreover, we found that the AURKA(V352I) mutant activates AKT signaling and increases nuclear beta-catenin, but AURKA(WT) only activates membrane form beta-catenin, which may account for the differences. In this study, we provide a new insight, that the AURKA(V352I) mutation contributes to early onset hepatocarcinogenesis, possibly through activation of different pathways than AURKA(WT). This transgenic fish may serve as a drug-screening platform for potential precision medicine therapeutics.
Fluorescent B-10 embedded nanodiamonds as B-10 delivery agent for boron neutron capture therapy
(2019-06-26)
Lin, Bo-Rong
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Kunuku, Srinivasu
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Chen, Tzung-Yuang
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Chang, Yu-Jen
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Liao, Li-Chuan
Boron neutron capture therapy is a potentially powerful anti-cancer treatment, the success of which depends heavily on the boron delivery agent. Enabling the real-time tracing of delivery agents as they move through the body is crucial to the further development of boron neutron capture therapy. In this study, we fabricate fluorescent B-10 embedded nanodiamonds using physical ion implantation in conjunction with a two-step annealing process. Fluorescent B-10 embedded nanodiamonds perform well in cell viability test. The red fluorescence of the B-10 embedded nanodiamonds allows their use in fluorescence microscopy and in vivo imaging systems, thereby making it possible to conduct tracking in real time. The proposed fluorescent B-10 embedded nanodiamonds, combining optical visibility and B-10 transport capability, might be a promising boron delivery agent suitable for a wide range of biomedical applications.
Performance Enhancement for Tungsten-Doped Indium Oxide Thin Film Transistor by Hydrogen Peroxide as Cosolvent in Room-Temperature Supercritical Fluid Systems
(2019-06-26)
Ruan, Dun-Bao
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Liu, Po-Tsun
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Yu, Min-Chin
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Chien, Ta-Chun
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Chiu, Yu-Chuan
In this study, hydrogen peroxide (H2O2) cosolvent, which was dissolved into supercritical-phase carbon dioxide fluid (SCCO2), is employed to passivate excessive oxygen vacancies of the high-mobility tungsten-doped indium oxide without any essential thermal process. With the detailed material analysis, the internal physical mechanism of the cosolvent effect or the interaction between the cosolvent solution and supercritical-phase fluid is well discussed. In addition, the optimized result has been applied for the thin film transistor device fabrication. As a result, the device with SCCO2 + H2O2 treatment exhibits the lowest subthreshold swing of 82 mV/dec, the lowest interface trap density of 8.76 x 10(11) eV(-1) cm(-2), the lowest hysteresis of 47 mV, and an excellent reliability and uniformity characteristic compared with any other control groups. Besides, an extremely high field-effect mobility of 98.91 cm(2)/V s can also be observed, while there is even a desirable positive shift for the threshold voltage. Notably, compared with the untreated sample, the highest on/off current ratio of 5.11 x 10(7) can be achieved with at least four orders of magnitude enhancement by this unique treatment.
Electrical, Optical, and Thermal Transport Properties of Oxygen-Deficient Amorphous WOx (2.5 < x < 3) Films
(2019-06-27)
Kim, Gowoon
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Cho, Hai Jun
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Sheu, Yu-Miin
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Ohta, Hiromichi
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交大名義發表
Oxygen-deficient tungsten oxide (WOx) is known as an active material for various future applications such as smart displays, photocatalysts, Li-ion battery, and so on. WOx exhibits versatile properties depending on the valence state of W, which can vary from +6 to +4. Therefore, clarifying the relationship between x, the valence state of W ion, and the material properties of WOx is crucial for discovering more unique device applications. In case of crystalline WOx, since WOx has many different phases, the valence state of W cannot be modulated continuously from +6 to +4. On the other hand, there is no phase boundary in amorphous (a-) WOx, the valence state of W ion can be continuously modulated against x, and the effect of valence state of W on the material properties of WOx can be thoroughly examined. Here, we report the electrical, optical, and thermal properties of a-WOx films with several valence states of +6 (d(0)), +5 (d(1)), and +4 (d(2)) for x ranging from 2.511 to 2.982. Although the +6 dominant films were electrical insulators with optical transparency in the visible region, we found that both optical transmissivity and electrical resistivity decreased drastically with increase in the +5 concentrations, which also enhances the thermal conductivity because heat can be carried by additional conduction electrons. As the +4 state became dominant in the film, the resistivity slightly increased, whereas the low visible transmission was maintained. These results suggest that the redox of tungsten between +6 and +5 is attributed to all versatile properties of a-WOx, which would be of great use for developing unique devices in the future.
Contrapuntal Composition and Autonomous Style Development of Organum Motets by using AntsOMG
(2019-06-28)
Chang, Chun-yien
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Chen, Ying-ping
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資訊工程學系
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Department of Computer Science
球隊年度盛事——歡樂校友盃
(國立陽明大學, 2019-06-28)
陽明電子報編輯小組
本校各球隊每年最盛大的一場活動──校友盃球賽，即是邀請歷屆球隊的校友，撥冗回母校，與在校生攜手進行球賽交流！學長姐豐富的經驗與表現，都是學弟妹成長學習的典範，每年此時，在各球場揮汗打球與歡笑聲中，總能更拉近彼此間緊密的情誼！學弟妹們也非常感謝學長姐們一直以來的支持，以下就是今年各球隊所分享之108年排球 /男籃 /桌球 /女籃 /足球校友盃球賽精采回顧！他們也期盼明年，再次與學長姐切磋討教！
N,P co-coordinated Fe species embedded in carbon hollow spheres for oxygen electrocatalysis
(2019-06-28)
Zhu, Xiaofeng
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Tan, Xin
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Wu, Kuang-Hsu
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Chiang, Chao-Lung
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Lin, Yu-Chang
The increasing interest in fuel cell technology and metal-air batteries has led to the need for stable and effective catalyst materials to replace noble metal (such as Pt) based benchmarks for the oxygen reduction reaction (ORR). In this study, carbon hollow spheres with highly dispersed nitrogen and phosphorus co-coordinated iron atoms (FeNPC) on their surface have been successfully fabricated, exhibiting exceptional ORR activity in both alkaline and acidic solutions. Specifically, the obtained FeNPC catalyst is capable of catalyzing the ORR with an onset potential of 1.03 V and a half-wave potential of 0.88 V (both vs. the reversible hydrogen electrode) in alkaline solution, outperforming the commercial Pt/C catalyst under identical conditions. Experimental results and theoretical simulations reveal that the quasi-octahedral O-2-FeNxPy species are the active sites of the FeNPC composite. These species modify the electronic configuration of Fe centers and weaken the adsorption of the OH* intermediate, thereby promoting the ORR process. Additionally, the FeNPC catalyst also displays a catalytic activity towards the anodic oxygen evolution reaction (OER), making it an active air electrode catalyst in rechargeable Zn-air batteries with a high peak power density of 233.2 mW cm(-2) and an excellent cycling stability at 3 mA cm(-2) for over 15 h.
《文生去看海》（Vincent will Meer）
(國立陽明大學, 2019-06-28)
黃柏威
;
陽明電子報編輯小組
【高雄市陽明大學校友會】豫劇皇后王海玲的分享與傳承
(國立陽明大學, 2019-06-28)
陽明電子報編輯小組
【藥理所～藥品產業創新領域碩士學分班】
(國立陽明大學, 2019-06-28)
陽明電子報編輯小組
【與大師的對話】美國密蘇里大學張恩慈教授
(國立陽明大學, 2019-06-28)
陽明電子報編輯小組
Extraction of eight-band k . p parameters from empirical pseudopotentials for GeSn
(2019-06-28)
Liu, Shao-Qi
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Yen, Shun-Tung
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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
We extract the parameters for the eight-band k . p model for Ge 1 - x Sn x ( x <= 0.15 ) from the calculation of the nonlocal empirical pseudopotential method with the modified virtual crystal approximation. The atomic pseudopotential form factors of Ge are improved such that the calculated Ge band structure has the commonly accepted bandgap and effective masses. The improved Ge parameters are used in proper interpolation to derive the parameters of GeSn for empirical pseudopotential calculation. The calculated band structures suggest that the Ge 1 - x Sn x alloys exhibit a transition between an indirect bandgap semiconductor and a direct one at Sn composition x c = 0.071. From the calculation, we extract the bandgap, the split-off energy, the interband momentum matrix element, and the effective masses of Ge 1 - x Sn x ( x <= 0.15) as functions of x. From these results, we further derive the parameters used in the eight-band k . p model. These parameters are well expressed in quadratic form. The k . p model with the extracted parameters can give an interband tunneling current in a pin diode that is consistent with the current calculated by the empirical pseudopotential method.
「達文西」驚喜現身陽明，畢業生搶先體驗先進微創手術系統
(國立陽明大學, 2019-06-28)
陽明電子報編輯小組
全球最先進的微創手術系統──達文西機械手臂手術系統，在畢業週驚喜現身陽明，讓陽明師生實地體驗！這是造價上億元的「達文西機...
Conformal Deposition of RuO2 on Cu via a Galvanic Cementation Reaction
(2019-06-28)
Lin, Chun
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Chou, Shih-Cheng
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Tso, Kuang-Chih
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Hsieh, Yi-Chieh
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Chan, Ting-Shan
We develop a seedless wet chemical process to deposit uniform RuO2 on a Cu substrate. Our approach entails the synthesis of volatile RuO4 colloids in a pH 9 aqueous solution from the oxidation of RuCl52- by ClO-, followed by a galvanic cementation reaction in which the Cu undergoes a mild oxidation in conjunction with the reduction of RuO4 to produce a dense and conformal RuO2 thin film on the Cu surface. The nature for the chemical reactions and constituents involved are investigated by UV-Vis, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Both as-deposited and annealed RuO2 films are characterized by scanning electron microscope and X-ray diffractometer. The as-deposited RuO2 film, with a thickness of 199 nm, reveals an amorphous structure and after an Ar annealing, becomes crystalline in rutile phase. In between the RuO2 and Cu, there are presence of CuO from the displacement cementation reaction, and Cu2O from the parasitic Cu corrosion as expected from the Pourbaix diagram. These Cu oxides, with a thickness of 330 nm, provide sufficient adhesive bonding between RuO2 and Cu. (c) The Author(s) 2019. Published by ECS.
【暑假接駁車行駛路線時間表】
(國立陽明大學, 2019-06-28)
陽明電子報編輯小組