Browsing by Issue Date, starting with "2019-10-28"

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Characterization of the spatially anamorphic phenomenon and temporal fluctuations in high-speed, ultra-high pixels-per-inch liquid crystal on silicon phase modulator
(2019-10-28)
Yang, Jhou-Pu
;
Wu, Feng-Ping
;
Wang, Pei-Sin
;
Chen, Huang-Ming Philip
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光電工程學系
High-birefringence liquid crystal (LC) in ultrathin LCOS panels was adopted to prepare high phase precision (mSTD =lambda/50) and phase accuracy (mAPAE%similar to 8%) with suppressed pixel-level crosstalk effects. In conjunction with optimized digital driving scheme, the zero order light loss was found directly related to the phase accuracy error. Meanwhile, the world's fastest pure phase modulation LCOS with a response time of similar to 0.87 ms at 45 degrees C was also achieved. The low-temporal flicker (P-P similar to 2.0%) with high-speed LC responses was demonstrated by applying new digital driving scheme. Finally, the 4K2 K LCOS-SLM (similar to 7000 PPI) was evaluated its difficulties and opportunities. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Electrically tunable gradient-index lenses via nematic liquid crystals with a method of spatially extended phase distribution
(2019-10-28)
Wang, Yu-Jen
;
Hsieh, Huai-An
;
Lin, Yi-Hsin
;
光電工程學系
;
Department of Photonics
The dilemma between tunable range of a lens power and an aperture size in gradient-index (GRIN) type of liquid crystal (LC) lenses is well known due to the limitation of birefringence of LC martials and the nature of soft matters. In order to overcome the dilemma of the power law, a multi-layered LC lens was previously proposed by us. However, the aperture size of GRIN LC lenses is still difficult to exceed 10 mm. In this paper, we proposed an electrically tunable GRIN LC lens via nematic liquid crystals with a method of spatially extended phase distribution. A GRIN LC lens with an aperture size of 20 mm is achieved. The proposed GRIN LC lens consists of two LC elements modulating wavefronts at different regions of the lens aperture extending to 20 mm. The lens power of the GRIN LC lens is continuously tunable, while the LC lens can function as a positive lens, a negative lens, and a bifocal lens. The proposed GRIN LC lens not only overcomes the dilemma of the power law but also provides a more practical approach that could benefit the ophthalmic applications and augmented reality systems. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Suppressing the Initial Growth of Sidewall GaN by Modifying AlN-Coated Patterned Sapphire with KOH-Based Etchant
(2019-10-29)
Hsu, Wen-Yang
;
Lian, Yuan-Chi
;
Wu, Pei-Yu
;
Yong, Wei-Min
;
Sheu, Jinn-Kong
Micron-sized patterned sapphire substrates (PSSs) with an ex situ sputtered AlN nucleation layer (NL) have been used to improve the performance of GaN-based light-emitting diodes (LEDs). The growth of GaN was enhanced not only from bottom c-plane, but also from the sidewall of the micron-sized patterns. In this study, KOH solution was used to etch AlN (especially sidewall AlN) for the first time. The additional etching process is very simple. It was found that KOH etching 1 min did enhance the light output power (LOP) of LED. However, with the increase of etching time to 4 min, the LOP decreased. Besides, the effect of remained AlN on GaN growth mechanism was investigated in detail. (C) The Author(s) 2019. Published by ECS.
Electron Beam Irradiation-Induced Deoxidation and Atomic Flattening on the Copper Surface
(2019-10-30)
Lin, Ting-Yi
;
Lee, Shih-Kuang
;
Huang, Guan-Min
;
Huang, Chun-Wei
;
Tai, Kuo-Lun
Electron beam (e-beam) has been developed for nanomaterial observation and moreover to induce structural evolutions in atomic scale. In this work, we demonstrate the deoxidation of cuprous oxide (Cu2O) and the formation of an atomically flat surface on a Cu nanowire by e-beam irradiation. To develop e-beam irradiation applications, the relation between e-beam radiation and the atomic surface is significant. Through the density functional theory simulation of atomic sputtering, an obvious disparity in the sputtering threshold has been found under different structural conditions, which leads to different structural evolutions. Both surface deoxidation and atomic surface flattening reactions have been identified as self-limiting and irreversible processes via in situ transmission electron microscope observation. Under e-beam irradiation, the dynamic mechanism of atomic surface flattening is driven by the convergence of total surface energy and confirmed by climbing-image nudged elastic band (ci-NEB) calculations. With precise control, e-beam irradiation reveals enormous potentials in atomic surface engineering.
Investigation of the Capacitance-Voltage Electrical Characteristics of Thin-Film Transistors Caused by Hydrogen Diffusion under Negative Bias Stress in a Moist Environment
(2019-10-30)
Chen, Hong-Chih
;
Kuo, Chuan-Wei
;
Chang, Ting-Chang
;
Lai, Wei-Chih
;
Chen, Po-Hsun
In this study, the impact of moisture on the electrical characteristics of an amorphous In-Ga-Zn-O thin-film transistor (a-IGZO TFT) was investigated. In commercial applications of such TFTs, high stability and quality performance in humid environments are essential. During TFT operation under ambient moisture, the electrolysis of water molecules occurs via the tip electric field effect. Hydrogen diffuses from the etch-stop layer or back-channel into the main channel under a negative electric field. The hydrogen atoms act as shallow donors (which causes the carrier concentration in the channel to rise), causing the threshold voltage (V-TH) to shift in the negative direction. Hydrogen diffusion from the overlap of the source/drain and gate electrodes to the channel center caused by the tip electric field induces a significant barrier lowering and V-TH shifts in a short-channel device. However, under negative bias stress (NBS) in ambient moisture, the negative V-TH shift is more obvious in short- than in long-channel devices, indicating suppressed hydrogen diffusion in long-channel devices. This is attributed to the electrolysis of water by the tip electric field at the source, drain, and gate electrodes, which causes hydrogen to diffuse to the center of the channel. Here, a novel physical model of the capacitance-voltage (C-V) electrical property changes under ambient moisture is proposed, based on the early appearance of abnormalities in the C-V measurements. The electrolysis of water caused by the tip electric field and electrical abnormalities caused by hydrogen diffusion into the a-IGZO active layer are explained by this model. A secondary-ion mass spectrometry analysis shows that hydrogen content in the channel generally increases under NBS in ambient moisture. The degradation behavior due to moisture in a-IGZO is clarified. Thus, inhibiting the tip electric field may benefit future flexible-display and gas-sensing applications.
【11月生技咖啡館】再生醫學與3D列印的火花
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
環衛所發表首份國內警消調查報告，關懷警消高壓族群
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
陽明環境與職業衛生研究所日前公布國內第一份警消人員健康調查報告，研究發現，常處於高壓工作環境下的警消人員，每一百人中有七...
【FUN心住－居家消防安全講座】～災害省思及應變要領
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
【山腰電影院@大禮堂】《幸福綠皮書》電影放映與賞析會
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
【慈青Ｘ綠創聯合～拒菸反毒環保淨山】
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
【樂生在陽明】醫病、生活文物展
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
【IRB進階教育訓練】未成年研究對象及進入校園收案的倫理議題
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
護理學院研究證實，智慧光照可提升長者睡眠品質
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
陽明護理學院與南亞光電產學合作，建置智慧光照實驗室，探索各種光譜及照度在醫療應用的可行性。初步研究發現，高齡長者在模擬自...
陽明攜手交大主辦「海峽兩岸跨領域前瞻生醫研討會」
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
陽明與國立交通大學確定推動合校案後，兩校首度攜手主辦「第二屆海峽兩岸跨領域前瞻生醫研討會」，針對前瞻醫材、藥物傳輸、生物...
牙醫學院研究證實，咀嚼能力對預防失智的重要
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
經常咀嚼固態食物可刺激大腦，有助於預防失智！台灣前進文化發展協會10月22日舉辦的「常咀嚼，健康老；口靈活，樂生活」記者會，...
盛況空前的熱舞社迎新週
(國立陽明大學, 2019-10-31)
熱舞社
;
陽明電子報編輯小組
陽明熱舞社迎新社課文
【2019 陽明大學秋季智齡講堂】
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
【守仁樓教師休息室『Medicine Faculty Lounge』開幕典禮】
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
【學研攜手～醫材加速器服務平台暨影像檢測系統】實機展示說明會
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
功夫高手，人社外籍老師教哲學也教太極
(國立陽明大學, 2019-10-31)
陽明電子報編輯小組
很難想像一位從南非來的外籍老師，竟然說著一口流利的中文；更難想像的是，他最初來台灣，竟是為了學習武術！人文與社會教育...