Browsing by Issue Date, starting with "2013-08-07"

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The formation mechanisms and optical characteristics of GaSb quantum rings
(2013-08-07)
Lin, Wei-Hsun
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Wang, Kai-Wei
;
Liao, Yu-An
;
Pao, Chun-Wei
;
Lin, Shih-Yen
The growth mechanisms and optical characteristics of GaSb quantum rings (QRs) are investigated. Although As-for-Sb exchange is the mechanism responsible for the dot-to-ring transition, significant height difference between GaSb quantum dots (QDs) and QRs in a dot/ring mixture sample suggests that the dot-to-ring transition is not a spontaneous procedure. Instead, it is a rapid transition procedure as long as it initiates. A model is established to explain this phenomenon. Larger ring inner diameters and heights of the sample with longer post Sb soaking time suggest that As-for-Sb exchange takes places in both vertical and lateral directions. The decreasing ring densities, enlarged ring inner/outer diameters and eventually flat GaSb surfaces observed with increasing growth temperatures are resulted from enhanced adatom migration and As-for-Sb exchange with increasing growth temperatures. (C) 2013 AIP Publishing LLC.
DECISION METHOD CONSIDERING TIME AND POWER CONSUMPTION FOR OFFLOADING COMPUTATION AND COMPUTING SYSTEM
(2013-08-08)
Lin Ying-Dar
;
Huang Ting-Jun
;
Lai Yuan-Cheng
;
Chu Tsung-Hsien
A decision method considering time and power consumption for offloading computations is provided. The method includes: obtaining a computing mission; obtaining a plurality of static effect factors from an effect factor table; collecting a plurality of dynamic effect factors. The method also includes: generating power consumptions and computing time that each of the computing unit and each of the server consumes according to the dynamic effect factors and the static effect factors; calculating cost values of executing the computing mission according to the power consumptions and the computing time; determining a target unit to execute the computing mission according to the cost values, in which the target unit is a computing unit or a server; executing the computing mission by the target unit. Therefore, the power consumptions and the computing time are simultaneously considered, and computations are adequately allocated to one of the computing unit and the servers.
EDUCATIONAL GAMING DEVICE FOR LEARNING EVOLUTIONISM
(2013-08-08)
Cheng Meng-Tzu
;
Lin Yu-Wen
;
She Hsiao-Ching
An educational gaming device for learning evolutionism comprises a display device, a storage device and an operation unit. The storage device stores at least one scene and a plurality of corresponding representative creatures. The storage device and the display device are coupled to the operation unit. The operation unit selects at least two creatures from the representative creatures to respectively function as at least one player character and at least one non-player character. The operation unit drives the display device to show the process of interactivity and evolution of the player character and the non-player character in the scene. The game of the present invention features clear rules, instant feedbacks and competitions, and has much more interaction with the users than common instructional activities or common educational animations.
Nonequilibrium transport of helical Luttinger liquids through a quantum dot
(2013-08-08)
Chao, Sung-Po
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Silotri, Salman A.
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Chung, Chung-Hou
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電子物理學系
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Department of Electrophysics
We study a steady-state nonequilibrium transport between two interacting helical edge states of a two-dimensional topological insulator, described by helical Luttinger liquids, through a quantum dot. For a noninteracting dot, the current is obtained analytically by including the self-energy correction to the dot's Green function. For an interacting dot, we use the equation-of-motion method to study the influence of weak on-site Coulomb interaction on the transport. We find the metal-to-insulator quantum phase transition for attractive or repulsive interactions in the leads when the magnitude of the interaction strength characterized by a charge sector Luttinger parameter K goes beyond a critical value. The critical Luttinger parameter K-cr depends on the hopping strengths between the dot and the leads, as well as the energy level of the dot with respect to the Fermi levels of the leads, ranging from the weak-interaction regime for the dot level off-resonance to the strong-interaction regime for the dot in resonance with the equilibrium Fermi level. Near the transition, there are various singular behaviors of current noise, dot density of state, and the decoherence rate (inverse of lifetime) of the dot, which are briefly discussed.
Invariance in the recurrence of large returns and the validation of models of price dynamics
(2013-08-09)
Chang, Lo-Bin
;
Geman, Stuart
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Hsieh, Fushing
;
Hwang, Chii-Ruey
;
應用數學系
Starting from a robust, nonparametric definition of large returns ("excursions"), we study the statistics of their occurrences, focusing on the recurrence process. The empirical waiting-time distribution between excursions is remarkably invariant to year, stock, and scale (return interval). This invariance is related to self-similarity of the marginal distributions of returns, but the excursion waiting-time distribution is a function of the entire return process and not just its univariate probabilities. Generalized autoregressive conditional heteroskedasticity (GARCH) models, market-time transformations based on volume or trades, and generalized (Levy) random-walk models all fail to fit the statistical structure of excursions.
High-efficiency wet electrocyclone for removing fine and nanosized particles
(2013-08-09)
Lin, Guan-Yu
;
Le-Thi Cuc
;
Lu, Wei
;
Tsai, Chuen-Jinn
;
Chein, Hung-Min
This study designed and tested a wet electrocyclone with high efficiency for long-term operation. The inner diameter of the collection electrode is 25 cm, and the discharge electrodes consist of seven circular discs with zigzag-shaped edges for particle charging and removal. The tip of the circular saw-type discs is 20 pin in diameter and the tip to the inner wall (collection electrode) spacing is 4 cm. Cleaning water near the inter wall was used to keep the collection electrodes clean. Experimental results showed that the collection efficiency of the present wet electrocyclone decreased with an increasing air flow rate. The efficiency for oleic acid (OA) particles was reduced only slightly from 78-92% to 75-90% for particles from 22.1 to 805 nm in electrical mobility diameter (d(p)) after 6 h of micro-Al2O3 loading test. In the field test, the collection efficiencies of the present wet electrocyclone for submicron SiO2 particles with mass concentration of 20-50 mg/m(3) were also found to keep higher than 93% for continuous 14-day operation. A modified Deutsch-Anderson model was developed to predict the charged particle collection efficiency (eta(elec,p), %) of nanoparticle as well as larger particles. The present model is eta(elec,p) (%) = 1 - exp{-[A(N-De(B)) + C(N-De) + D]} x 100%, where A, B, C and D are regression coefficients, and N-De is the modified Deutsch number. Good agreement was obtained between the present predictions and experimental data. (C) 2013 Elsevier B.V. All rights reserved.
New bounds on the average information rate of secret-sharing schemes for graph-based weighted threshold access structures
(2013-08-10)
Lu, Hui-Chuan
;
Fu, Hung-Lin
;
應用數學系
;
Department of Applied Mathematics
A secret-sharing scheme is a protocol by which a dealer distributes shares of a secret key among a set of n participants in such a way that only qualified subsets of participants can reconstruct the secret key from the shares they received, while unqualified subsets have no information about the secret key. The collection of all qualified subsets is called the access structure of this scheme. The information rate (resp. average information rate) of a secret-sharing scheme is the ratio between the size of the secret key and the maximum size (resp. average size) of the shares. In a weighted threshold scheme, each participant has his or her own weight. A subset is qualified if and only if the sum of the weights of participants in the subset is not less than the given threshold. Morillo et al. [19] considered the schemes for weighted threshold access structure that can be represented by graphs called k-weighted graphs. They characterized this kind of access structures and derived a result on the information rate. In this paper, we deal with the average information rate of the secret-sharing schemes for these structures. Two sophisticated constructions are presented, each of which has its own advantages and both of them perform very well when n/k is large. (C) 2013 Elsevier Inc. All rights reserved.
Asymmetric design of photonic crystal surface-emitting lasers with low-threshold characteristics
(2013-08-10)
Hung, Chih-Tsang
;
Ho, Tsung-Lin
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Lu, Tien-Chang
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光電工程學系
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Department of Photonics
We present AlGaAs-InGaAs multiquantum wells photonic crystal surface-emitting lasers by using the transfer matrix method and coupled wave method to achieve a low-threshold operation. The extremely low-threshold gain is achieved by adopting an asymmetric cladding layer design to enhance both of the vertical optical confinement factors for the quantum wells and photonic crystal (PC). By modifying the composition of the AlGaAs layer to raise the refractive index in the p-type cladding, optical field distribution will obviously be shifted to the p side. Hence, it results in a significant coupling enhancement between the optical mode profile and the PC layer. The optimized value of the vertically optical confinement factor of the PC layer is 13.94%, and the corresponding threshold gain can be as low as 19.45 cm(-1). (C) 2013 Optical Society of America
無線感測網路中具省電效果之骨幹導向結構、建立方法及修復方法
(2013-08-11)
黃貴笠
;
吳昭男
;
王瑞堂
;
曾建超
本發明提供一種無線感測網路中具省電效果之骨幹導向結構、建立方法及修復方法，其係利用具電節點建立連接伺服器之骨幹網路，並將有限電量之一般節點連接至骨幹網路，當有一具電節點損壞時，後端之具電節點會搜尋通訊範圍內是否有其他骨幹之具電節點可重新連線，若沒有則透過一般節點建立臨時通道，等待損壞之具電節點修好即可還原無線感測網路。由具電節點所構成之骨幹網路可舒緩熱點問題對一般節點之影響，增加骨幹網路之韌性，延長無線感測網路之壽命。
顯示裝置之畫素驅動電路
(2013-08-11)
劉柏村
;
竹立煒
本發明係有關於一種顯示裝置之畫素驅動電路，其由一第一開關耦接一供應電壓，並受控於一切換訊號而提供供應電壓，一第二開關耦接該第一開關，並受控於一第一掃描訊號；一第三開關耦接第二開關與一資料線，並受控於一第二掃描訊號；一驅動元件耦接第三開關與一發光元件，並用以驅動發光元件；一儲存電容之第一端耦接於第一開關與第二開關之間，儲存電容之第二端耦接驅動元件；一第四開關耦接於儲存電容之第二端，並耦接驅動元件與發光元件之間，且受控於第二掃描訊號。如此，本發明藉由使用與臨界電壓無關之驅動電流，而增加驅動電流的均勻性使面板可長時間操作，而減少亮度不均勻的特性。
Multi-functional stacked light-trapping structure for stabilizing and boosting solar-electricity efficiency of hydrogenated amorphous silicon solar cells
(2013-08-12)
Huang, Wen-Hsien
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Shieh, Jia-Min
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Pan, Fu-Ming
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Shen, Chang-Hong
;
Huang, Jung Y.
A sandwiched light-trapping electrode structure, which consists of a capping aluminum-doped ZnO (AZO) layer, dispersed plasmonic Au-nanoparticles (Au-NPs), and a micro-structured transparent conductive substrate, is employed to stabilize and boost the conversion-efficiency of hydrogenated amorphous silicon (a-Si:H) solar cells. The conformal AZO ultrathin layer (5 nm) smoothened the Au-NP-dispersed electrode surface, thereby reducing defects across the AZO/a-Si:H interface and resulting in a high resistance to photo-degradation in the ultraviolet-blue photoresponse band. With the plasmonic light-trapping structure, the cell has a high conversion-efficiency of 10.1% and the photo-degradation is as small as 7%. (C) 2013 AIP Publishing LLC.
Chemo-, Regio- and Stereoselective Tricyclohexylphosphine-Catalyzed [3+2] Cycloaddition of Enynes with [60]Fullerene Initiated by 1,4-Michael Addition: Synthesis of Cyclopenteno[60]fullerenes and their Electrochemical Properties
(2013-08-12)
Tseng, Po-Yen
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Chuang, Shih-Ching
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應用化學系
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Department of Applied Chemistry
Herein we demonstrate a tricyclohexylphosphine-catalyzed cycloaddition of (E)- or (Z)-alkyl 5-substituted phenylpent-2-en-4-ynoates with [60]fullerene to give cyclopentenofullerenes in good to excellent yields, through initial chemo- and regioselective 1,4-addition of phosphines at the -carbon of the enyne substrates. The nucleophilic addition pattern of P(cHx)(3) is found to be different from that of Gilman or Grignard reagents toward the studied enynes. The resulting cyclopentenofullerenes, characterized with spectrometric methods and single crystal X-ray diffraction analysis, exhibit comparable or higher LUMO energy levels than a typical n-type material, [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM).
Exciton wave function localization and exciton diamagnetic coefficient in semiconductor quantum rings without reflection symmetry
(2013-08-12)
Voskoboynikov, Oleksandr
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Chiu, W. T.
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Thu, L. M.
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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 theoretically study how reflection asymmetry affects the neutral exciton diamagnetic coefficient in self-assembled InGaAs/GaAs semiconductor wobbled quantum rings. The previously proposed mapping method is used to simulate the exciton wave function and energy in the rings. The description is suited to clarify the important question of the exciton diamagnetic coefficient stability in the rings with broken reflection symmetry. Our simulation results confirm that the exciton wave function of the reflection symmetrical (balanced) wobbled ring is distributed equally over two potential valleys corresponding to the hills in the ring's shape. At the same time, even a very small reflectional imbalance in the geometry and (or) material content of the wobbled rings destroys the ringlike shape of the exciton wave function and causes the localization of the function in one of the potential valleys of the ring (dotlike shape of the exciton wave function). This leads to a rapid decrease of the exciton diamagnetic coefficient. Our calculation results are in good agreement with recent experimental observations.
Microtubule-Associated Type II Protein Kinase A Is Important for Neurite Elongation
(2013-08-13)
Huang, Yung-An
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Kao, Jun-Wei
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Tseng, Dion Tzu-Huan
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Chen, Wen-Shin
;
Chiang, Ming-Han
Neuritogenesis is a process through which neurons generate their widespread axon and dendrites. The microtubule cytoskeleton plays crucial roles throughout neuritogenesis. Our previous study indicated that the amount of type II protein kinase A (PKA) on microtubules significantly increased upon neuronal differentiation and neuritogenesis. While the overall pool of PKA has been shown to participate in various neuronal processes, the function of microtubule-associated PKA during neuritogenesis remains largely unknown. First, we showed that PKA localized to microtubule-based region in different neurons. Since PKA is essential for various cellular functions, globally inhibiting PKA activity will causes a wide variety of phenotypes in neurons. To examine the function of microtubule-associated PKA without changing the total PKA level, we utilized the neuron-specific PKA anchoring protein MAP2. Overexpressing the dominant negative MAP2 construct that binds to type II PKA but cannot bind to the microtubule cytoskeleton in dissociated hippocampal neurons removed PKA from microtubules and resulted in compromised neurite elongation. In addition, we demonstrated that the association of PKA with microtubules can also enhance cell protrusion using the non-neuronal P19 cells. Overexpressing a MAP2 deletion construct which does not target PKA to the microtubule cytoskeleton caused non-neuronal cells to generate shorter cell protrusions than control cells overexpressing wild-type MAP2 that anchors PKA to microtubules. Finally, we demonstrated that the ability of microtubule-associated PKA to promote protrusion elongation was independent of MAP2 phosphorylation. This suggests other proteins in close proximity to the microtubule cytoskeleton are involved in this process.
Electrostatic discharge protection device
(2013-08-13)
Huang Yeh-Jen
;
Jou Yeh-Ning
;
Ker Ming-Dou
;
Chen Wen-Yi
;
Hung Chia-Wei
An electrostatic discharge (ESD) protection device including a substrate, a first doped region, a second doped region, and a third doped region, a gate and a plurality of contacts is disclosed. The substrate includes a first conductive type. The first doped region is formed in the substrate and includes a second conductive type. The second doped region is formed in the substrate and includes the second conductive type. The third doped region is formed in the substrate, includes the first conductive type and is located between the first and the second doped regions. The gate is formed on the substrate, located between the first and the second doped regions and comprises a first through hole. The contacts pass through the first through hole to contact with the third doped region.
Vehicle license plate recognition method and system thereof
(2013-08-13)
Hsieh Jun-Wei
;
Chen Sin Yu
A vehicle license plate recognition method and a system thereof are disclosed. A region where a vehicle license plate image exists is detected according to the edge densities of an input image and a vehicle license plate specification. A text area of the vehicle license plate image is divided into a plurality of character images. The character images are binarized to obtain a plurality of binarized character images. A plurality of characters is recognized from the binarized character images. The characters are recombined to form a character string. The abovementioned steps are repeated to obtain a new character string from another image of the same vehicle, which is captured at a next time point. The character string is compared with the new character string character by character to obtain a comparison result for verifying reliability of recognition through a voting technique.
Porous Polymer Nanostructures Fabricated by the Surface-Induced Phase Separation of Polymer Solutions in Anodic Aluminum Oxide Templates
(2013-08-13)
Wei, Tzu-Hui
;
Chi, Mu-Huan
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Tsai, Chia-Chan
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Ko, Hao-Wen
;
Chen, Jiun-Tai
We study the formation of porous polymer nanostructures fabricated by the surface-induced phase separation of polymer solutions in anodic aluminum oxide (AAO) templates. Poly(methyl methacrylate) (PMMA) and tetrahydrofuran (THF) are used to investigate the evolution process of the surface-induced phase separation. With the longer immersion time of the AAO template in the polymer solution, the size of the solvent-rich droplet is increased by the coarsening process, resulting in the formation of porous polymer nanostructures. The coarsening mechanism is further evaluated by changing the experimental parameters including the immersion time, the polymer concentration, the polymer molecular weight, and the solvent quality. Under conditions in which polymer solutions have higher viscosities, the coarsening process is slowed down and the formation of the porous nanostructures is prohibited. The prevention of the porous nanostructures can also be realized by adding water to the PMMA/THF solution before the immersion process.
Bonding method for three-dimensional integrated circuit and three-dimensional integrated circuit thereof
(2013-08-13)
Chen Kuan-Neng
;
Hsu Sheng-Yao
The present invention discloses a bonding method for a three-dimensional integrated circuit and the three-dimensional integrated circuit thereof. The bonding method comprises the steps of: providing a substrate; depositing a film layer on the substrate; providing a light source to light onto the film layer to form a graphic structure; forming a metal co-deposition layer by a first metal and a second metal that are co-deposited on the film layer; providing a first integrated circuit having the substrate, the film layer and the metal co-deposition layer sequentially; providing a second integrated circuit that having the metal co-deposition layer, the film layer and the substrate sequentially; and the first integrated circuit is bonded with the second integrated circuit at a predetermined temperature to form a three-dimensional integrated circuit.
Sharp variation in coercivity and magnetic interactions in patterned CoxNi1-x nanoarrays
(2013-08-14)
Yang, Chao-Yao
;
Wang, Liang-Wei
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Chen, Po-An
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Lin, Hong-Ji
;
Lai, Chih-Huang
We present a study concerning the unexpectedly large coercivity increase and associated magneto-structural properties of CoxNi1-x patterned arrays. An increase in x led to an face-center-cubic (FCC)-> hexagonal-close-packed (HCP) transition in CoxNi1-x arrays, accompanied by a 6-fold increase in coercivity and strong 3d exchange interactions probed by x-ray magnetic circular dichroism. Sum-rule analysis revealed that orbital moment involved very little in the variable coercivity and magnetic anisotropy; this is distinct from other nanostructures displaying variable coercivity. The sharp rise in coercivity can be attributed to the geometrical confinement of the arrays, causing the microstructure of the nano-clusters to switch magnetization reversal mechanism from fanning to coherent with increasing x, based on the chain-of-spheres model. First-order-reversal curves revealed that the FCC and HCP arrays comprised both soft and hard ferromagnetic components; however, the soft component of the FCC was much more pronounced, leading to differences in reversibility. This type of nanostructure provides a sharp control of magnetic hardness that could be tailored in related technologies. (C) 2013 AIP Publishing LLC.
Efficiency Enhancement of PEDOT:PSS/Si Hybrid Solar Cells by Using Nanostructured Radial Junction and Antireflective Surface
(2013-08-14)
Chen, Jheng-Yuan
;
Con, Celal
;
Yu, Ming-Hung
;
Cui, Bo
;
Sun, Kien Wen
We demonstrate the implementation of a hybrid solar cell that comprises a surface nanostructured n-type Si and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). The Si surface before deposition of the organic layer was nanostructured by using CsCl self-assembled nanoparticles as a hard mask and dry etching to form radial junction architectures and enhance light diffusion and absorption. Apart from the textured Si surface, processing parameters such as from metal-electrode shadow ratio, spin-coating rate, and surfactant addition were properly adjusted to improve overall cell performance. Our hybrid solar cells achieve the best performance under optimized cell parameters with a power conversion efficiency of 8.84% and short-circuit current density of 30.5 mA/cm(2). This combined technique provides a simple, scalable, and cost-effective process for fabricating hybrid solar cells.