Browsing by Issue Date, starting with "2019-07-20"

Now showing 1 - 20 of 7199

Combination of electrophoresis and electro-flocculation for the formation of adhering IrO2 pH sensing films
(2019-07-20)
Wang, Han-Yi
;
Hsieh, Yi-Chieh
;
Tso, Kuang-Chih
;
Chang, Chung-Kai
;
Cheng, Yu-Ting
We demonstrate a simple scheme to produce dense and adhering IrO2 thin films on ITO substrates via a bipolar pulsing process combining both electrophoresis and electro-flocculation. Our fabrication steps entail the synthesis of negatively-charged IrO2 nanoparticles in size of 3.5 nm using NaClO as an oxidizer in conjunction with Na3IrCl6, citric acid, and NaOH. Subsequently, multiple bipolar potentiostatic pulses are imposed in which alternating positive and negative potentials engender the electrophoresis of IrO2 nanoparticles, followed by their immediate coalescence facilitated by proton-catalyzed electro-floccu-lation. The resulting IrO2 thin films reveal impressive physical properties in surface uniformity, robust structural integrity, and strong adhesion to the substrate. The as-synthesized IrO2 thin film exhibits an amorphous nature with a pH sensing slope between -73.6 and -71.5 mV/pH, characteristic of super-Nernstian behavior. In contrast, the annealed IrO(2 )sample demonstrates a crystalline rutile phase with a pH sensing slope between -49.5 and -54.7 mV/pH, consistent with typical Nernstian response. Our approach provides a new route for the formation of strong and adhering oxide films from their colloidal constituents. (C) 2019 Elsevier Ltd. All rights reserved.
Hybrid electrolyte enables safe and practical 5 V LiNi0.5Mn1.5O4 batteries
(2019-07-21)
Rath, Purna Chandra
;
Wu, Chia-Jung
;
Patra, Jagabandhu
;
Li, Ju
;
Lee, Tai-Chou
Bis(trifluoromethylsulfonyl)imide (TFSI)-based ionic liquid (IL) has high thermal and electrochemical stability, but it is not an ideal battery electrolyte due to the poor rate capability of cells that use it, problematic anode compatibility, and high cost. The incorporation of a carbonate solvent could mitigate these problems, but it would also lead to serious Al current collector corrosion at high potential. This long-existing problem is overcome in this study by modulating the LiTFSI concentration and IL/carbonate ratio in the hybrid electrolyte. The Al corrosion and electrolyte decomposition side reactions at 5 V (vs. Li+/Li) can be suppressed in 3 M LiTFSI 25%-IL electrolyte, in which good performance of a high-voltage LiNi0.5Mn1.5O4 (LNMO) cathode is achieved. Capacities of 140 and 88 mA h g(-1) were measured at 0.1 and 2C, respectively (vs. 25 mA h g(-1) at 2C for a plain LiTFSI/PMP-TFSI IL electrolyte). After 300 charge-discharge cycles, 90% of the initial LNMO capacity was retained. This electrolyte also shows low flammability and great wettability toward a polyethylene separator. Moreover, this electrolyte allows elevated-temperature storage and operation of LNMO cells at 55 degrees C, which is not possible with the conventional carbonate electrolyte. Good compatibility of the electrolyte with a graphite anode is also demonstrated. The proposed electrolyte design concept has great potential for next-generation 5 V Li-ion batteries.
An optical system for augmented reality with electrically tunable optical zoom function and image registration exploiting liquid crystal lenses
(2019-07-22)
Wang, Yu-Jen
;
Lin, Yi-Hsin
;
光電工程學系
;
Department of Photonics
An optical-see-through augmented reality (AR) system assists our daily work by augmenting our sense with computer-generated information. Two of optical challenges of AR are image registration and vision correction due to fixed optical properties of the optical elements of AR systems. In this paper, we demonstrated an AR system with optical zoom function as well as a function of image registration via two LC lenses in order to help people see better by magnifying the virtual image and adjusting the location of virtual image. The operating principles are introduced, and experiments are performed. The concept demonstrated in this paper could be further extended to other electro-optical devices as long as the devices exhibit the capability of phase modulations. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Plug-and-play fiber to waveguide connector
(2019-07-22)
Gordillo, Oscar A. Jimenez
;
Chaitanya, Shriddha
;
Chang, You-Chia
;
Dave, Utsav D.
;
Mohanty, Aseema
The mass production and commercialization of integrated photonics have been slowed down by the high cost of packaging its optical interfaces. We show a plug-and-play connector between a fiber and a nanophotonic waveguide consisting of a 3D polymer structure with a fiber entrance port that simultaneously achieves mechanical and optical passive alignment with tolerance beyond +/- 10 mu m to the fiber input position. We take advantage of a mechanical and optical co-design, analogous to commercial fiber-to-fiber connectors. We fabricate the plug-and-play couplers using 3D nanoprinting directly on foundry fabricated diffraction grating couplers. We measure an average of only 0.05 dB excess coupling loss between a single mode fiber and a high confinement silicon waveguide in addition to the inherent grating coupler loss. Our coupling platform offers a passive plug-and-play solution for scalable integrated photonics fiber-chip packaging. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Liquid crystal beyond displays: feature introduction
(2019-07-22)
Lin, Yi-Hsin
;
Hu, Wei
;
Lin, Tsung-Hsien
;
d'Alessandro, Antonio
;
交大名義發表
The editors introduce the feature issue on liquid crystal beyond displays. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Large-Area and Strain-Reduced Two-Dimensional Molybdenum Disulfide Monolayer Emitters on a Three-Dimensional Substrate
(2019-07-24)
Chang, Chiao-Yun
;
Lin, Hsiang-Ting
;
Lai, Ming-Sheng
;
Yu, Cheng-Li
;
Wu, Chong-Rong
Atomically thin membranes of two-dimensional (2-D) transition-metal dichalcogenides (TMDCs) have distinct emission properties, which can be utilized for realizing ultrathin optoelectronic integrated systems in the future. Growing a large-area and strain-reduced monolayer 2-D material on a three-dimensional (3-D) substrate with microstructures or nanostructures is a crucial technique because the electronic band structure of TMDC atomic layers is strongly affected by the number of stacked layers and strain. In this study, a large-area and strain-reduced MoS2 monolayer was fabricated on a 3D substrate through a two-step growth procedure. The material characteristics and optical properties of monolayer TMDCs fabricated on the nonplanar substrate were examined. The growth of monolayer MoS2 on a cone-shaped sapphire substrate effectively reduced the tensile strain induced by the substrate by decreasing the thermal expansion mismatch between the 2-D material and the substrate. Monolayer MoS2 grown on the nonplanar substrate exhibited uniform strain reduction and luminescence intensity. The fabrication of monolayer MoS2 on a nonplanar substrate increased the light extraction efficiency. In the future, large-area and strain-reduced 2-D TMDC materials grown on a nonplanar substrate can be employed as novel light-emitting devices for applications in lighting, communication, and displays for the development of ultrathin optoelectronic integrated systems.
Oxide Heteroepitaxy-Based Flexible Ferroelectric Transistor
(2019-07-24)
Tsai, Meng-Fu
;
Jiang, Jie
;
Shao, Pao-Wen
;
Lai, Yu-Hong
;
Chen, Jhih-Wei
With the rise of Internet of Things, the presence of flexible devices has attracted significant attention owing to design flexibility. A ferroelectric field-effect transistor (FeFET), showing the advantages of high speed, nondestructive readout, and low-power consumption, plays a key role in next-generation technology. However, the performance of these devices is restricted since conventional flexible substrates show poor thermal stability to integrate traditional ferroelectric materials, limiting the compatibility of wearable devices. In this study, we adopt flexible muscovite mica as a substrate due to its good thermal properties and epitaxial integration ability. A flexible FeFET composed of oxide heteroepitaxy on muscovite is realized by combining an aluminum-doped zinc oxide film as the semiconductor channel layer and a Pb(Zro7Ti0.3)03 film as the ferroelectric gate dielectric. The excellent characteristics of the transistor together with superior thermal stability and mechanical flexibility are demonstrated through various mechanical bending and temperature measurements. The on/off current ratio of the FeFET is higher than 103, which based on the field effect in the transfer curve. The smallest bending radius that can be achieved is 5 mm with a cyclability of 300 times and a retention of 100 h. This study opens an avenue to use oxide heteroepitaxy to construct a FeFET for next-generation flexible electronic systems.
Hydrogen Abstraction/Addition Tunneling Reactions Elucidate the Interstellar H2NCHO/HNCO Ratio and H-2 Formation
(2019-07-24)
Haupa, Karolina A.
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Tarczay, Gyorgy
;
Lee, Yuan-Pern
;
交大名義發表
;
應用化學系
Formamide (H2NCHO) is the smallest molecule possessing the biologically important amide bond. Recent interstellar observations have shown a strong correlation between the abundance of formamide and isocyanic acid (HNCO), indicating that they are likely to be chemically related, but no experiment or theory explains this correlation satisfactorily. We performed H + H2NCHO reactions in a para-hydrogen quantum-solid matrix host and identified production of H2NCHO and HNCO from hydrogen-abstraction reactions. We identified also D2NCO, DNCO, HDNCO, and HDNCHO from the reaction H + D2NCHO, indicating the presence of hydrogen-addition reactions of DNCO and HDNCO. From the observed temporal profiles of H2NCHO, H2NCO, HNCO, and their deuterium isotopologues, we showed that a dual-cycle consisting of hydrogen abstraction and hydrogen addition can satisfactorily explain the quasi-equilibrium between H2NCHO and HNCO and explain other previous experimental results. Furthermore, this mechanism also indicates that the catalytic formation of H-2 from H atoms might occur in interstellar ice grains.
【108年動物中心使用說明會】
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
Infrared Emission from Photodissociation of Methyl Formate [HC(O)OCH3] at 248 and 193 nm: Absence of Roaming Signature
(2019-07-25)
Lanfri, Lucia Y.
;
Wang, Yen-Lin
;
Pham, Tien V.
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Nghia Trong Nguyen
;
Paci, Maxi Burgos
Following photodissociation at 248 nm of gaseous methyl formate (HC(O)OCH3, 0.73 Torr) and Ar (0.14 Torr), temporally resolved vibration-rotational emission spectra of highly internally excited CO (nu <= 11, J <= 27) in the 1850-2250 cm(-1) region were recorded with a step-scan Fourier-transform spectrometer. The vibration-rotational distribution of CO is almost Boltzmann, with a nascent average rotational energy (E-R(0)) of 3 +/- 1 kJ mol(-1) and a vibrational energy (E-v(0)) of 76 +/- 9 kJ mol(-1). With 3 Torr of Ar added to the system, the average vibrational energy was decreased to E-v(0) = 61 +/- 7 kJ mol(-1). We observed no distinct evidence of a bimodal rotational distribution for nu = 1 and 2, as reported previously [Lombardi et al., J. Phys. Chem. A 2016, 129, 5155], as evidence of a roaming mechanism. The vibrational distribution with a temperature of similar to 13000 +/- 1000 K, however, agrees satisfactorily with trajectory calculations of these authors, who took into account conical intersections from the S-1 state. Highly internally excited CH3OH that is expected to be produced from a roaming mechanism was unobserved. Following photodissociation at 193 nm of gaseous HC(O)OCH3 (0.42 Torr) and Ar (0.09 Torr), vibration-rotational emission spectra of CO (nu <= 4, J <= 38) and CO2 (with two components of varied internal distributions) were observed, indicating that new channels are open. Quantum-chemical calculations, computed at varied levels of theory, on the ground electronic potential-energy schemes provide a possible explanation for some of our observations. At 193 nm, the CO2 was produced from secondary dissociation of the products HC(O)O and CH3OCO, and CO was produced primarily from secondary dissociation of the product HCO produced on the S-1 surface or the decomposition to CH3OH + CO on the S-0 surface.
第九屆海峽兩岸醫學生交流活動
(國立陽明大學, 2019-07-25)
湯于萱
;
陽明電子報編輯小組
海峽兩岸醫學生交流活動，是一年一度為兩岸醫學生搭起的學術與文化交流活動，參加成員包括：北京大學醫學部、陽明大學、高雄醫學大學、中國醫藥大學與台灣大學醫學院。來自北京與台灣各地的醫學生在本活動相遇，分享彼此的所思、所學、所想；在學術上激盪出嶄新的思維，在文化上認識彼此的歷史故事與人生閱歷。
【學生餐廳8/31前暫停營業】
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
Enhanced photovoltaic performance of dye-sensitized solar cells by the adsorption of Zn-porphyrin dye molecule on TiO2 surfaces
(2019-07-25)
Lin, Yanming
;
Zhu, Chaoyuan
;
Jiang, Zhenyi
;
Zhao, Yali
;
Wang, Qi
The electronic structure, optical absorption and charge transfer performances of Zn-porphyrin (ZnPP) dye molecule adsorbed on anatase (101) and rutile (110) TiO2 surfaces have been investigated systematically using spin-polarized density functional theory calculations. The calculated results indicate that the strong interactions of ZnPP dye molecule and TiO2 surfaces cause an obvious variation of the conduction band minimum and valence band maximum for ZnPP dye molecule adsorbed on TiO2 surfaces, and the valence band of adsorption systems has a large bandwidth compared with that of the TiO2 bulk and surfaces, which induces a red-shift of the optical absorption edge and improves greatly the optical absorption of adsorption systems in the ultraviolet and visible light regions. Moreover, the change of charge density indicates that the photoelectrons transfer from the ZnPP dye molecule to TiO2 across the interface, and a built-in electric field is formed at the interface, which effectively enhances the separation of photogenerated electron-hole pairs. These results suggest that the sensitized actions of ZnPP dye molecule on TiO2 surfaces can generate an excellent photovoltaic performance of TiO2 photoanode in DSSCs. (c) 2019 Elsevier B.V. All rights reserved.
【生技醫療創新創業講座】～公司形象、議題設定與媒體風向
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
【108年實驗動物基本技術操作技能】
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
【108年暑期課程】個人電腦的安全防護
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
【2019畢業校友現況調查】102、104、106學年度畢業校友～填問卷三重好禮等著你！！！
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
2019北美費城生技展，陽明GLORIA團隊大放異彩
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
全球生技界每年最大產業活動──北美生技展（Bio International Convention），2019年6月在美國東岸費城盛大展開。陽明國際產學...
擺渡人
(國立陽明大學, 2019-07-25)
薛元智
;
陽明電子報編輯小組
亞洲首台小動物二合一影像儀落腳榮陽，加速新藥研發流程
(國立陽明大學, 2019-07-25)
陽明電子報編輯小組
高階醫療科技的正子與磁振二合一影像，現在小動物也可以做了。陽明採購市值超過一億的「小動物7T正子暨核磁共振影像儀」（7T micr...