Browsing by Issue Date, starting with "2020-08-12"

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Intrinsic Ultralow-Threshold Laser Action from Rationally Molecular Design of Metal-Organic Framework Materials
(2020-08-12)
Bera, Krishna Prasad
;
Kamal, Saqib
;
Inamdar, Arif I.
;
Sainbileg, Batjargal
;
Lin, Hung-, I
Metal-organic frameworks (MOFs) are superior for multiple applications including drug delivery, sensing, and gas storage because of their tunable physiochemical properties and fascinating architectures. Optoelectronic application of MOFs is difficult because of their porous geometry and conductivity issues. Recently, a few optoelectronic devices have been fabricated by a suitable design of integrating MOFs with other materials. However, demonstration of laser action arising from MOFs as intrinsic gain media still remains challenging, even though some studies endeavor on encapsulating luminescence organic laser dyes into the porous skeleton of MOFs to achieve laser action. Unfortunately, the aggregation of such unstable laser dyes causes photoluminescence quenching and energy loss, which limits their practical application. In this research, unprecedently, we demonstrated ultralow-threshold (similar to 13 nJ/cm(2)) MOF laser action by a judicious choice of metal nodes and organic linkers during synthesis of MOFs. Importantly, we also demonstrated that the white random lasing from the beautiful microflowers of organic linkers possesses a porous network, which is utilized to synthesize the MOFs. The highly luminescent broad-band organic linker 1,4-NDC, which itself exhibits a strong white random laser, is used not only to achieve the stimulated emission in MOFs but also to reduce the lasing threshold. Such white lasing has multiple applications from bioimaging to the recently developed versatile Li-Fi technology. In addition, we showed that the smooth facets of MOF microcrystals can show Fabry-Perot resonant cavities having a high quality factor of similar to 10(3) with excellent photostability. Our unique discovery of stable, nontoxic, high-performance MOF laser action will open up a new route for the development of new optoelectronic devices.
Light-Induced Nanowetting: Erasable and Rewritable Polymer Nanoarrays via Solid-to-Liquid Transitions
(2020-08-12)
Lin, Kuan-Ting
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Chen, Yu-Jia
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Huang, Meng-Ru
;
Karapala, Vamsi Krishna
;
Ho, Jhih-Hao
Template wetting methods have been widely applied in the preparation of one-dimensional (1D) polymer nanomaterials. The pattern control using the template wetting methods, however, still remains a great challenge, mainly due to the nonselectivity of the polymers toward the environmental triggering. In this work, we present a facile light-induced nanowetting (LIN) method to fabricate patterned nanoarrays using anodic aluminum oxide (AAO) templates. Photoresponsive azobenzene-containing polymers (azopolymers) that exhibit light-induced reversible solidto-liquid transitions are used. Upon exposure to ultraviolet lights, the azopolymer chains can wet the nanopores of the AAO templates in a liquid state via capillary force. The azopolymer chains are then solidified by illuminating them with visible lights, resulting in the formation of azopolymer nanoarrays. Notably, using designed photomasks, the patterns of the nanoarrays can be ingeniously controlled with the characteristic of erasable and rewritable nanostructures.
New gravimetric-only and hybrid geoid models of Taiwan for height modernisation, cross-island datum connection and airborne LiDAR mapping
(2020-08-12)
Hwang, Cheinway
;
Hsu, Hung-Jui
;
Featherstone, W. E.
;
Cheng, Ching-Chung
;
Yang, Ming
This paper combines gravity data collected from airborne, shipborne and terrestrial surveys and those derived from satellite altimetry to determine a high-resolution gravimetric and hybrid geoid model (on a 30" x 30 '' grid) in and around Taiwan. Some 6000 new land gravity values at a 0.03-mGal precision make a notable contribution to the geoid modeling. Shipborne gravity data in waters 20 km offshore Taiwan were collected to improve the coastal geoid precision. In a circular area of 50 km around each of the five major tide gauges in Taiwan, gravity data were measured to improve vertical datum connections between Taiwan and its four offshore islands. Height anomalies were computed first and then converted to geoid heights. At > 2000 benchmarks, we obtained measured geoid heights to assess the gravimetric-only geoid and to create a hybrid geoid. Our assessments and formal errors from least-squares collocation indicate few cm of standard deviations for both geoid models, but the gravimetric geoid has mean differences of up to 20 cm with the measured geoidal heights. The hybrid geoid is used in RTK-VBS orthometric heighting, achieving a 5-cm precision. The gravimetric geoid is used to determine the relative differences in the ocean's mean dynamic topography (MDT) between Taiwan and the four offshore islands, which are also compared with those from oceanic and altimetric methods for estimating MDT. Differences in MDT help to identify 41.7 cm and 54.1 cm offsets in the current vertical datums of Penghu and Lanyu islands. In a low-lying, flood-prone region of southern Taiwan, the hybrid geoid improves LiDAR mapping of sub-zero elevation zones by 20 cm, corresponding to 70 years of sea level rise at an assumed rate of 0.286 cm/yr.
Fano feature induced by a bound state in the continuum via resonant state expansion
(2020-08-13)
Pankin, Pavel S.
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Maksimov, Dmitrii N.
;
Chen, Kuo-Ping
;
Timofeev, Ivan, V
;
影像與生醫光電研究所
We consider light scattering by an anisotropic defect layer embedded into anisotropic photonic crystal in the spectral vicinity of an optical bound state in the continuum (BIC). Using a resonant state expansion method we derive an analytic solution for reflection and transmission amplitudes. The analytic solution is constructed via a perturbative approach with the BIC as the zeroth order approximation. The solution is found to describe the collapsing Fano feature in the spectral vicinity of the BIC. The findings are confirmed via comparison against direct numerical simulations with the Berreman transfer matrix method.
Attention and Functional Connectivity Among Patients With Early-Stage Subcortical Ischemic Vascular Disease and Alzheimer's Disease
(2020-08-13)
Tu, Min-Chien
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Hsu, Yen-Hsuan
;
Yang, Jir-Jei
;
Huang, Wen-Hui
;
Deng, Jie Fu
The current study compared attention profiles and functional connectivity of frontal regions in patients with early-stage subcortical ischemic vascular disease (SIVD) and Alzheimer's disease (AD). Twenty patients with SIVD, 32 patients with AD, and 23 subjects with normal cognition (NC) received cognition and resting-state functional MRI (rs-fMRI) evaluations. The Cognitive Abilities Screening Instrument (CASI) was used to assess global cognition, and simple attention, processing speed, divided attention, and vigilance/sustained attention were evaluated using the Digit Span Forward, Trail Making Test, Symbol Digit Modality Test, and Conners Continuous Performance Test, respectively. Voxel-based regional homogeneity (ReHo) derived from rs-fMRI data was analyzed to identify significant clusters, which were further correlated with attention profiles. Although the patients with SIVD and AD had comparable global cognitive ability, those with SIVD exhibited worse divided attention and vigilance/sustained attention than those with AD. Compared with the NC group, the patients with SIVD exhibited decreased ReHo within the right middle frontal gyrus (MFG) and left anterior cingulate gyrus (ACG), whereas the patients with AD exhibited increased ReHo within the right orbital part of frontal regions. Correlations between these three clusters with attention exhibited distinct patterns according to the dementia subtype, as did attention indices with significance in predicting global cognition. In summary, our study suggested that worse attention performance was associated with functional disconnection within the frontal regions among patients with SIVD than in those with AD. Frontal functional disconnection may underlie the pathogenesis responsible for defective divided attention, vigilance/sustained attention, and notable within-group variations identified in SIVD.
Giant photothermal nonlinearity in a single silicon nanostructure
(2020-08-14)
Duh, Yi-Shiou
;
Nagasaki, Yusuke
;
Tang, Yu-Lung
;
Wu, Pang-Han
;
Cheng, Hao-Yu
Silicon photonics have attracted significant interest because of their potential in integrated photonics components and all-dielectric meta-optics elements. One major challenge is to achieve active control via strong photon-photon interactions, i.e. optical nonlinearity, which is intrinsically weak in silicon. To boost the nonlinear response, practical applications rely on resonant structures such as microring resonators or photonic crystals. Nevertheless, their typical footprints are larger than 10 mu m. Here, we show that 100nm silicon nano-resonators exhibit a giant photothermal nonlinearity, yielding 90% reversible and repeatable modulation from linear scattering response at low excitation intensities. The equivalent nonlinear index is five-orders larger compared with bulk, based on Mie resonance enhanced absorption and high-efficiency heating in thermally isolated nanostructures. Furthermore, the nanoscale thermal relaxation time reaches nanosecond. This large and fast nonlinearity leads to potential applications for GHz all-optical control at the nanoscale and super-resolution imaging of silicon.
Direct large-area growth of graphene on silicon for potential ultra-low-friction applications and silicon-based technologies
(2020-08-14)
Tseng, Wei-Shiuan
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Chen, Yen-Chun
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Hsu, Chen-Chih
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Lu, Chen-Hsuan
;
Wu, Chih-, I
Deposition of layers of graphene on silicon has the potential for a wide range of optoelectronic and mechanical applications. However, direct growth of graphene on silicon has been difficult due to the inert, oxidized silicon surfaces. Transferring graphene from metallic growth substrates to silicon is not a good solution either, because most transfer methods involve multiple steps that often lead to polymer residues or degradation of sample quality. Here we report a single-step method for large-area direct growth of continuous horizontal graphene sheets and vertical graphene nano-walls on silicon substrates by plasma-enhanced chemical vapor deposition (PECVD) without active heating. Comprehensive studies utilizing Raman spectroscopy, x-ray/ultraviolet photoelectron spectroscopy (XPS/UPS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and optical transmission are carried out to characterize the quality and properties of these samples. Data gathered by the residual gas analyzer (RGA) during the growth process further provide information about the synthesis mechanism. Additionally, ultra-low friction (with a frictional coefficient similar to 0.015) on multilayer graphene-covered silicon surface is achieved, which is approaching the superlubricity limit (for frictional coefficients <0.01). Our growth method therefore opens up a new pathway towards scalable and direct integration of graphene into silicon technology for potential applications ranging from structural superlubricity to nanoelectronics, optoelectronics, and even the next-generation lithium-ion batteries.
Realizing a Cosolvent System for Stable Tin-Based Perovskite Solar Cells Using a Two-Step Deposition Approach
(2020-08-14)
Shahbazi, Saeed
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Li, Meng-Yu
;
Fathi, Amir
;
Diau, Eric Wei-Guang
;
交大名義發表
Applying a two-step procedure and solvent engineering, we fabricated a stable tin-based perovskite, formamidinium tin triiodide (FASnI(3)), solar cell for lead-free photovoltaic applications. The first step was deposition of a SnI2 layer with the solvent dimethyl sulfoxide; the second step was application of a cosolvent system containing hexafluoro-2-propanol (HFP), isopropyl alcohol (IPA), and chlorobenzene (CB) in a 5:5:2 ratio to deposit the FAI layer on the SnI2 layer. The traditional IPA solvent prevented the formation of a stable FASnI(3) layer such that a stable device could not be fabricated. HFP was hence used to form hydrogen bonds with IPA and FM to retard the crystal growth of FASnI(3); CB served as the antisolvent. Ethylenediammonium dihypophosphite in the first step was an effective reducing agent to increase the efficiency of power conversion from similar to 5% to similar to 7% with great reproducibility and stability over 4000 h.
【實驗場所職業安全衛生教育訓練】
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
為提昇校園實驗場所安全衛生觀念，降低災害風險，加強實驗場所.
【IRB教育訓練Ｉ】醫療器材法規與管理制度簡介
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
日期：8月31日（一）時間：18:00-21:00（IRB時數：3）
陽明輔具中心主辦，2020全球首發輔具長照大展
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
由陽明「ICF暨輔助科技研究中心」與展昭國際公司共同主辦的「2020臺灣長期照護大展」，7月30日至8月2日在台北南港展覽館盛大登場..
陽明深耕創客教育，「3D列印工程師」認證率全國最高
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
今年「經濟部3D列印工程師」第一次認證考試，全國共有613人報考、獲證率僅3成。陽明「3D列印工程師認證班」考生獲證率卻高達七成...
陽明攜手醫療財經專家，探討新冠病毒對策
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
新冠病毒疫情為全世界帶來巨大衝擊，各國紛紛祭出因應對策。陽明大學防疫科學研究中心與台灣經濟學會、臺灣大學社會科學院，7月30.
《小丑》（Joker）
(國立陽明大學, 2020-08-15)
黃柏威
;
陽明電子報編輯小組
Oriented Si3N4 crystallites formed by plasma nitriding of SiO2/Si (111) substrate
(2020-08-15)
Yu, Chang-Hua
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Chiu, Kun-An
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Do, Thi-Hien
;
Chang, Li
;
材料科學與工程學系
We show that formation of oriented Si3N4 crystallites can be obtained by plasma nitriding of 20 nm thick SiO2 amorphous layer on Si (111) wafer. Nitriding is achieved at temperature in the range of 800-1000 degrees C with microwave plasma using gas mixture of N-2 and H-2. Results of x-ray diffraction and Raman spectroscopy show that both alpha-Si3N4 and beta-Si3N4 are formed on the nitrided substrate and are strongly oriented in {1 (1) over bar 00} for both phases. The morphologies of the nitrided surfaces as shown by scanning electron microscopy exhibit elongated Si3N4 crystallites aligned with Si < 110 >. Cross-sectional transmission electron microscopy image reveals that the Si3N4/Si interface is sharp without residual SiO2.
生化所王琬菁副教授榮獲科技部「吳大猷先生紀念獎」
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
「中心體纖毛複合體」是細胞不可或缺的構造，其結構或功能的異常會造成纖毛性病變，然而相關的分子機制至今仍有許多重要的議題未
【一般場所職業安全衛生教育訓練】
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
健康是人類幸福的基礎，人必須在生理、心理、社會方面達到基本
Hydrogel-based zinc ion sensor on optical fiber with high resolution and application to neural cells
(2020-08-15)
Tsai, May-Jywan
;
Cheng, Henrich
;
Ho, Hsin-Hsien
;
Lin, Peng-Wei
;
Liou, Dann-Ying
Solid-state zinc ion sensor is developed with high enough resolution and reproducibility for the potential application in brain injury monitoring. An optical diffuser is incorporated into the zinc ion sensor based on optical fiber and hydrogel doped with the fluorescent zinc ion probe molecule meso-2,6-Dichlomphenyltripyrrinone (TPN-Cl-2). The diffuser transforms the high-peak-intensity excitation light near the fiber end into a broad light with moderate local intensity to reduce the degradation of the probe molecule. Reversible detection can be reached for 1, 2, and 5 mu m (10(-6) Molar), with slopes 0.3, 0.6, and 0.8 respectively. This is the pathophysiological concentration range after brain injury. The sensor is applied to neuron-glial cultures and macrophage under the stimulation of lipopolysaccharide (LPS), KCl and oxygen/glucose deprivation (OGD) that reflect inflammation, depolarization and ischemia respectively, mimicking events after brain injury. The zinc ion level is raised to 4-5 mu m after LPS treatment, and then reduced to <3 mu m after the co-treatment with the herbal drug silymarin. The results suggest the conditions of the neural cells under stress can be monitored.
陽明防疫中心全球大數據研究：新冠肺炎死亡率與檢測數及政府效能相關
(國立陽明大學, 2020-08-15)
陽明電子報編輯小組
新冠肺炎在全球已造成超過1500萬人感染，超過60萬人死亡。面臨全球感染人數及死亡人數屢創新高，台灣也可能面對疫情再次來襲的風
Low temperature deposition of high quality single crystalline AlN thin films on sapphire using highly oriented monolayer MoS 2 as a buffer layer
(2020-08-15)
Chien, Hung-Yi
;
Kuo, Po-Chun
;
Kao, Hui-Ling
;
Chen, Jyh-Shin
;
Chen, Meei-Ru