Browsing by Issue Date, starting with "2014-11-14"

Now showing 1 - 20 of 24992

Enhanced thermal radiation in terahertz and far-infrared regime by hot phonon excitation in a field effect transistor
(2014-11-14)
Chung, Pei-Kang
;
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 demonstrate the hot phonon effect on thermal radiation in the terahertz and far-infrared regime. A pseudomorphic high electron mobility transistor is used for efficiently exciting hot phonons. Boosting the hot phonon population can enhance the efficiency of thermal radiation. The transistor can yield at least a radiation power of 13 mu W and a power conversion efficiency higher than a resistor by more than 20%. (C) 2014 AIP Publishing LLC.
An ultra-efficient energy transfer beyond plasmonic light scattering
(2014-11-14)
Fu, Sze-Ming
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Zhong, Yan-Kai
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Lin, Albert
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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
The energy transfer between nano-particles is of great importance for, solar cells, light-emitting diodes, nano-particle waveguides, and other photonic devices. This study shows through novel design and algorithm optimization, the energy transfer efficiency between plasmonic and dielectric nano-particles can be greatly improved. Using versatile designs including core-shell wrapping, supercells and dielectric mediated plasmonic scattering, 0.05 dB/mu m attenuation can be achieved, which is 20-fold reduction over the baseline plasmonic nano-particle chain, and 8-fold reduction over the baseline dielectric nano-particle chain. In addition, it is also found that the dielectric nanoparticle chains can actually be more efficient than the plasmonic ones, at their respective optimized geometry. The underlying physics is that although plasmonic nano-particles provide stronger coupling and field emission, the effect of plasmonic absorption loss is actually more dominant resulting in high attenuation. Finally, the group velocity for all design schemes proposed in this work is shown to be maintained above 0.4c, and it is found that the geometry optimization for transmission also boosts the group velocity. (C) 2014 AIP Publishing LLC.
CaY2Si2S8:Ce3+: a novel green-emitting thiosilicate phosphor for white light-emitting diodes
(2014-11-14)
Lee, Szu-Ping
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Huang, Chien-Hao
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Chen, Teng-Ming
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應用化學系
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應用化學系分子科學碩博班
A novel green-emitting Ce3+-doped CaY2Si2S8 thiosilicate phosphor was synthesized by using solid-state methods in a sealed silica ampoule. This compound could be excited over a broad range from UV to blue light (400-450 nm) and generated a broadband emission peaking at similar to 495 nm, with a quantum efficiency of similar to 57%, which is promising for solid-state lighting applications. Temperature-dependent optical measurements of CaY2Si2S8:Ce3+ from 25 to 225 degrees C were performed. In addition, a white LED device was fabricated by using the green-emitting CaY2Si2S8:Ce3+ phosphor and commercially-available red-emitting CaAlSiN3:Eu2+ pumped with a 450 nm blue chip. The CRI value and CCT were measured to be 91-95 and 3800-8600 K, respectively, showing promising potential for solid-state lighting applications. The preparation, spectroscopic characterization, quantum efficiency, decay lifetime, thermal stability, and related LED device data are also presented.
Efficient cooperative access class barring with load balancing and traffic adaptive radio resource management for M2M communications over LTE-A
(2014-11-14)
Hsu, Yi-Huai
;
Wang, Kuochen
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
We propose two efficient cooperative access class barring with load balancing (CACB-LB) and traffic adaptive radio resource management (TARRM) schemes for M2M communications over LTE-A. The proposed CACB-LB uses the percentage of the number of Machine-Type Communication (MTC) devices that can only access one eNB between two adjacent eNBs as a criterion to allocate those MTC devices that are located in the overlapped coverage area to each eNB. Note that an eNB is a base station of LTE-A. In this way, the proposed CACB-LB can achieve better load balancing among eNBs than CACB, which is the best available related work. The proposed CACB-LB also uses the ratio of the channel quality indication that an MTC device received from an eNB over the number of MTC devices that attach to the eNB as a criterion to adjust the estimated number of MTC devices that may access the eNB. As a result, the proposed CACB-LB can have a better set of barring rates of access class barring than CACB and can reduce random access delay experienced by an MTC device, which is also applicable to user equipment (UE). After an MTC device successfully accesses to an eNB, the eNB needs to allocate radio resources for the MTC device. In addition, the proposed TARRM allocates radio resources for an MTC device based on the random access rate of the MTC device and the amount of data uploaded and downloaded by the MTC device in a homogeneous MTC device network, and the priority of an MTC device in a heterogeneous MTC device network. Furthermore, we use the concept from cognitive radio networks such that if there are unused physical resource blocks (PRBs) of UEs, an eNB can schedule MTC devices to use these PRBs to enhance the throughput performance. Simulation results show that either in a homogeneous MTC device network or in a heterogeneous MTC device network, the proposed CACB-LB\'s average access delay of UEs/MTC devices and average throughput from UEs/MTC devices are better than CACB\'s. The proposed CACB-LB with TARRM\'s average throughput from UEs/MTC devices is also higher than CACB\'s. Therefore, the proposed CACB-LB with TARRM is feasible for M2M communications over LTE-A. (C) 2014 Elsevier B.V. All rights reserved.
Using protein-encapsulated gold nanoclusters as photoluminescent sensing probes for biomolecules
(2014-11-15)
Selvaprakash, Karuppuchamy
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Chen, Yu-Chie
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應用化學系
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Department of Applied Chemistry
In this study, we generated gold nanoclusters (AuNCs) using inexpensive chicken egg white proteins (AuNCs@ew) as reagents. AuNCs@ew were generated by reacting aqueous tetrachloroauric acid with diluted chicken egg white under microwave heating (90 W) through subsequent heating cycles (5 min/cycle). Within 10 cycles, red photoluminescent AuNCs@ew with maximum emission wavelength at similar to 640 nm (lambda(ex)=370 nm) were obtained. The quantum yield of the as-generated AuNCs was similar to 6.6%. The intact and the tryptic digest of AuNCs@ew were characterized by mass spectrometry. The results showed that the AuNCs@ew were mainly derived from ovalbumin, i.e., the major protein in egg white, encapsulated AuNCs. The AuNCs@ew also has the common features found in AuNCs@protein, which is sensitive to the presence of heavy metal ions such as Cu2+. The photoluminescence of the AuNCs@ew was quenched with the addition of Cu2+. Furthermore, the photoluminescence of the quenched AuNCs@ew can be restored in the presence of the molecules containing phosphate functional groups because of the strong binding affinity between Cu2+ and phosphates. We used the AuNCs@ew-Cu2+ conjugates as switch-on sensing probes for the detection of phosphate containing metabolites such as adenosine-5\'-triphosphate (ATP) and pyrophosphate (PPi). The results showed that the photoluminescence of the sensing probes increased as the concentration of the phosphate-containing molecules in the sample solution increased. The limits of detection achieved using the AuNCs@ew-Cu2+ for ATP and PPi were 19 and 5 mu M, respectively. Additionally, we also demonstrated the feasibility of using the AuNCs@ew as the sensing probes for lectins such as concanavalin A (Con A) based on the molecular recognitions between the glycan ligands on the AuNCs@ew and glycan binding sites on Con A. (C) 2014 Elsevier B.V. All rights reserved.
Preparation of superhydrophobic polyimide films modified with organosilicasol as effective anticorrosion coatings
(2014-11-15)
Lo, Teng-Yuan
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Huang, Yi-Chia
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Hsiao, Yi-Nan
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Chao, Chuen-Guang
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Whang, Wha-Tzong
In this study we prepared superhydrophobic polyimide (PI) hybrid coatings for anticorrosion application by adjusting their surface roughness and surface composition through spray-coating with silylated perfluoroalkylsilane-modified organosilicasol (silylated fluoro-organosilicasol), which increased the surface hydrophobicity. After silylation with 1,1,1,3,3,3-hexamethyldisilazane (HMDS), the silylated fluoro-organosilicasol further transformed the PI surface into a superhydrophobic state with a static water contact angle of greater than 1600 and a low hysteresis of 10 degrees. We examined the mechanism behind the enhancement in superhydrophobicity through analyses of the surface topology and chemical composition of the films, using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electron spectroscopy for chemical analysis (ESCA). These analyses suggested that both surface roughness and silylation of the fluoro-organosilicasol making more CF2 groups on the outmost surface rendered the surface hydrophobicity. The anticorrosion properties of these superhydrophobic coatings were also examined through Tafel measurement. These PI hybrid coatings demonstrated lower corrosion current density and nobler corrosion potential and higher polarization resistance. The enhancement in anticorrosion performance was believed to be contributed from the superhydrophobicity and dual barrier protection from the fully-covered fluoro-organosilicasol, insulating the metal from corrosive species in the medium. This superhydrophobic coating technique with good stability guaranteed better corrosion protection and also has great potential for application to other polymeric films. (C) 2014 Elsevier B.V. All rights reserved.
Decoding and encoding of visual patterns using magnetoencephalographic data represented in manifolds
(2014-11-15)
Kuo, Po-Chih
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Chen, Yong-Sheng
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Chen, Li-Fen
;
Hsieh, Jen-Chuen
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分子醫學與生物工程研究所
Visual decoding and encoding are crucial aspects in investigating the representation of visual information in the human brain. This paper proposes a bidirectional model for decoding and encoding of visual stimulus based on manifold representation of the temporal and spatial information extracted from magnetoencephalographic data. In the proposed decoding process, principal component analysis is applied to extract temporal principal components (TPCs) from the visual cortical activity estimated by a beamforming method. The spatial distribution of each TPC is in a high-dimensional space and can be mapped to the corresponding spatiotemporal component (STC) on a low-dimensional manifold. Once the linear mapping between the STC and the wavelet coefficients of the stimulus image is determined, the decoding process can synthesize an image resembling the stimulus image. The encoding process is performed by reversing the mapping or transformation in the decoding model and can predict the spatiotemporal brain activity from a stimulus image. In our experiments using visual stimuli containing eleven combinations of checkerboard patches, the information of spatial layout in the stimulus image was revealed in the embedded manifold. The correlation between the reconstructed and original images was 0.71 and the correlation map between the predicted and original brain activity was highly correlated to the map between the original brain activity for different stimuli (r = 0.89). These results suggest that the temporal component is important in visual processing and manifolds can well represent the information related to visual perception. (c) 2014 Published by Elsevier Inc.
Optimization of gefitinib analogues with potent anticancer activity
(2014-11-15)
Yin, Kai-Hao
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Hsieh, Yi-Han
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Sulake, Rohidas S.
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Wang, Su-Pei
;
Chao, Jui-I.
The interactions of gefitinib (Iressa) in EGFR are hydrogen bonding and van der Waals forces through quinazoline and aniline rings. However the morpholino group of gefitinib is poorly ordered due to its weak electron density. A series of novel piperazino analogues of gefitinib where morpholino group substituted with various piperazino groups were designed and synthesized. Most of them indicated significant anti-cancer activities against human cancer cell lines. In particular, compounds 52-54 showed excellent potency against cancer cells. Convergent synthetic approach has been developed for the synthesis of gefitinib intermediate which can lead to gefitinib as well as numerous analogues. (C) 2014 Elsevier Ltd. All rights reserved.
Gold nanoparticles conjugates-amplified aptamer immunosensing screen-printed carbon electrode strips for thrombin detection
(2014-11-15)
Yeh, Fang-Yuan
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Liu, Ting-Yu
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Tseng, I-Hua
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Yang, Chung-Wei
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Lu, Li-Che
Thrombin plays the role in cardiovascular diseases and regulates many processes in inflammation and could be a feature of many pathological conditions, including the thromboembolic disease, cancer and neurodegenerative diseases. An ultrasensitive and amplified electrochemical sandwich assay using screen-printed carbon electrode (SPCE) strips for thrombin detection was established in this study. The conductivity and sensing performance of the carbon electrodes were enhanced by using gold nanoparticles (AuNPs). The aptamer addressed on the strips was used as a primary probe to capture thrombin in the detected samples. An amplifier was invented for recognizing thrombin captured on the SPCE, which is the multiple molecules of anti-thrombin antibody (Ab) and horseradish peroxidase (HRP) co-modified AuNPs (AuNPs/Ab-HRP). Hydrogen peroxide was used as the substrate for HRP and then the response current (RC) could be detected. The optimization of these AuNPs conjugates-amplified aptamer immunosensing SPCE strips was conducted for thrombin detection. The detection sensitivity showed a linear relation between RC and thrombin concentration in the range of 10 pM-100 nM, and limit of detection (LOD) was 1.5 pM. The fabricated AuNPs/Ab-HRP-amplified aptamer immunosensing SPCE strips were further used to detect thrombin in human serum with a linear range of 100 pM-100 nM. This study provided the promising SPCE strips with highly sensitive and rapid detection for thrombin by the electrochemical aptasensor combined with AuNPs conjugates for amplifying the detection signal. (C) 2014 Elsevier B.V. All rights reserved.
GaAs Polariton Interference in Magnetic Field: Oblique Incident Ellipsometry Measurement
(2014-11-15)
Su, Sheng-Kai
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Voskoboynikov, Oleksandr
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Li, Liang-Chen
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Suen, Yuen-Wuu
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Lee, Chien-Ping
The properties of GaAs polaritons propagating in a magnetic field have been investigated using a self-designed ellipsometry system with an oblique incident angle. Interesting fine structures, which have not been reported, have been observed and their magneto-optical behavior cannot be explained by the known properties of excitonic states. Treating the surface and the growth interface as boundaries, we attribute the fine structures to the interference among various polariton modes. A model considering the polariton spatial dispersion and exciton effective mass increase induced by its center of mass and relative motion coupling is proposed to explain the magnetic response of interference ellipsometry spectra.
博士做麵包　健康樂逍窯
(2014-11-16)
劉敏慈
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Department of Communication and Technology
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傳播與科技學系
黃俊傑放棄高薪工作轉行烘焙業，當時有人覺得他瘋了，但是他用自己的毅力證明他做的到，而且還做得很好。
販賣回憶　復刻戲劇感動
(2014-11-16)
鄭宇茹
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Department of Communication and Technology
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傳播與科技學系
為拍攝需求，劇組自造場景並將其保留，在改建之後販賣劇中回憶，成了吸引劇迷朝聖的景點。
棋如人生　人生如棋
(2014-11-16)
許翔
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Department of Communication and Technology
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傳播與科技學系
從小到大下象棋的心路歷程。棋如人生，人生如棋，隨著年紀的增長，對於象棋的體悟也有所不同。
兩年一度　賽夏矮靈祭登場
(2014-11-16)
黃馨儀
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Department of Communication and Technology
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傳播與科技學系
兩年一度的賽夏族矮靈祭盛大登場。賽夏族人為了感念矮靈，以虔敬的祭儀呈現懺悔且敬畏的傳統信仰。
美國夢　是野心還是貪婪
(2014-11-16)
賴坤猷
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Department of Communication and Technology
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傳播與科技學系
電影【黑金企業】被譽為近十年來美國電影裡最經典的作品，而其中資本主義的意涵值得不斷深省。
地方廟宇　王爺廟口鑑古今
(2014-11-16)
陳亞柔
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Department of Communication and Technology
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傳播與科技學系
位於新北市蘆洲區中正路舊社區巷弄內的保佑宮，是蘆洲的第一間廟宇，宮內供奉著池府王爺。
仇恨　讓愛沉睡的魔咒
(2014-11-16)
李恬芳
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Department of Communication and Technology
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傳播與科技學系
【黑魔女：沉睡魔咒】中，對公主下咒的反派梅菲瑟成為主角，有別於以往的詮釋為童話題材的電影帶來新氣象。
時代的回憶
(2014-11-16)
郭穎慈
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Department of Communication and Technology
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傳播與科技學系
應該是我阿嬤的故事。
光源導引結構及發光裝置
(2014-11-16)
徐瑞坤
;
魏紹華
一種發光裝置，其包括：一基座單元、一光源導引結構及一罩體單元。光源導引結構設置在基座單元上。罩體單元包括一設置在基座單元上且包覆光源導引結構的透光罩體。其中，光源導引結構包括一導光單元及一發光單元，導光單元包括一單件式導光元件，單件式導光元件具有一柱狀體及一從柱狀體一體成型地向上延伸而出的外擴體，柱狀體具有一入光面及一直立狀環繞周圍表面，外擴體具有一連接於直立狀環繞周圍表面的環繞下表面、一連接於環繞下表面的傾斜狀環繞周圍表面、及一連接於傾斜狀環繞周圍表面的喇叭狀上表面，且發光單元包括至少一鄰近柱狀體的入光面的發光模組。
新社花海　綻放自然的美
(2014-11-16)
余念竹
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Department of Communication and Technology
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傳播與科技學系
占地近三十五公頃的花田，種植著多種花草植栽，展區結合新社特色推廣，吸引許多民眾來殺底片拍照留念。