Browsing by Issue Date, starting with "2011-01-11"

Now showing 1 - 20 of 42360

Manifestation of quantum-billiard eigenvalue statistics from subthreshold emission of vertical-cavity surface-emitting lasers
(2011-01-11)
Chen, Y. F.
;
Yu, Y. T.
;
Chiang, P. Y.
;
Tuan, P. H.
;
Huang, Y. J.
We report that the subthreshold emission spectra of vertical-cavity surface-emitting lasers (VCSELs) can be analogously used to manifest the quantum-billiard energy spectra. The Fourier-transformed distributions of the subthreshold emission spectra are demonstrated to display various peak structures that are in good agreement with the results of the quantum-billiard model. We also verify that the statistical analyses of the nearest-neighbor eigenvalue spacing distributions obey a Poisson distribution for an equilateral-triangular device and a Wigner distribution for a stadium-shaped device.
適用於多重載波通訊系統的通道估測方法
(2011-01-11)
吳文榕
;
林宛儀
;
高祥倫
一種通道估測方法，適用經過一通道的多重載波訊號。此方法先從多重載波訊號取出嚮導訊號，其中取出的嚮導訊號包括估測單元所在之當前符元的嚮導訊號以及前一個與後一個符元的嚮導訊號取平均值的額外嚮導訊號。接著，根據取出的嚮導訊號及原先置入的嚮導訊號，估測取出的嚮導訊號之子通道響應。最後，根據這些估測的子通道響應，估測該通道之響應。
跳躍式遞迴複雜圖形構圖法及具有可執行此構圖法之電腦程式的儲存媒體
(2011-01-11)
陳明璋
一種跳躍式遞迴複雜圖形構圖法及具有可執行此構圖法之電腦程式的儲存媒體。首先，設置起始物件及生成物件。經數次疊代形成過渡物件。再以此過渡物件為基礎進行跳躍遞迴；跳躍遞迴時，每次疊代的生成物件是用前次疊代後的結構性結果轉化為單一圖案，加上基準物件後所設計；每次疊代後的結果仍保留原來的結構，因此以結構為輸入的起始物件；第一次疊代的起始物件可以是不同的疊代物件的表徵。由於每次疊代的輸入結構相同，生成物件又是單一的圖案構成，因此每次疊代耗費計算資源相同，可避免計算資源指數成長，也節省大量計算資源、及避免系統運算量負荷過重。
Three-Dimensional Reconstruction of Brain-wide Wiring Networks in Drosophila at Single-Cell Resolution
(2011-01-11)
Chiang, Ann-Shyn
;
Lin, Chih-Yung
;
Chuang, Chao-Chun
;
Chang, Hsiu-Ming
;
Hsieh, Chang-Huain
Background: Animal behavior is governed by the activity of interconnected brain circuits. Comprehensive brain wiring maps are thus needed in order to formulate hypotheses about information flow and also to guide genetic manipulations aimed at understanding how genes and circuits orchestrate complex behaviors. Results: To assemble this map, we deconstructed the adult Drosophila brain into approximately 16,000. single neurons and reconstructed them into a common standardized framework to produce a virtual fly brain. We have constructed a mesoscopic map and found that it consists of 41 local processing units (LPUs), six hubs, and 58 tracts covering the whole Drosophila brain. Despite individual local variation, the architecture of the Drosophila brain shows invariance for both the aggregation of local neurons (LNs) within specific LPUs and for the connectivity of projection neurons (PNs) between the same set of LPUs. An open-access image database, named FlyCircuit, has been constructed for online data archiving, mining, analysis, and three-dimensional visualization of all single neurons, brain-wide LPUs, their wiring diagrams, and neural tracts. Conclusion: We found that the Drosophila brain is assembled from families of multiple LPUs and their interconnections. This provides an essential first step in the analysis of information processing within and between neurons in a complete brain.
Analyses and experimental confirmation of removal performance of silicon oxide film in the chemical-mechanical polishing (CMP) process with pattern geometry of concentric groove pads
(2011-01-12)
Wei, Chin-Chung
;
Horng, Jeng-Haur
;
Lee, An-Chen
;
Lin, Jen-Fin
;
機械工程學系
A Reynolds equation that considers both the smoothing hydrodynamic pressure and the pattern of surface topography at the polishing pads was used to solve the distribution of the hydrodynamic field. A three-body abrasion wear model for solving the removed thickness of silicon oxide films was also introduced to obtain the removal rate of SiO(2) film in a chemical-mechanical polishing (CMP) process. The suction hydrodynamic pressure field expands its region with increasing groove width and decreasing depth of grooves. The flow rate of the slurry was thus increased, and the removal rate also increased with an increased number of abrasive particles. The solid contact pressure was much higher than the hydrodynamic pressure. The three-body abrasion for the wear depth of a particle arises from the solid contacting pressure and is hence more important than the hydrodynamic pressure. The removal rate of the SiO(2) film was dominated by the number of abrasive particles, which was affected by the variation of the hydrodynamic pressure in addition to the wear depth controlled by the solid contact pressure. The thickness of the silicon oxide films removed increased with decreasing grooving width and depth. (C) 2010 Elsevier B.V. All rights reserved.
Method For Selecting Transmitting Points In A Communication System
(2011-01-13)
Huang, Chung-Jung
;
Sung, Chih-Sheng
;
Lee, Ta-Sung
The present invention provides a method for identifying a specific number of communicating points having relatively smallest accumulated path values from a plurality of transmitting points for a receiving point in a communication system. The method includes steps of: (a) defining a first coordination of each of the plurality of transmitting points and the receiving point on a complex plane; (b) transferring the first coordination of the receiving point to a second coordination thereof, in which the second coordination of the receiving point is near an origin of the complex plane; and (c) identifying the specific number of transmitting points having relatively smallest accumulated path values based on the second coordination of the receiving point.
CARRIER COMPRISING NANODIAMOND
(2011-01-13)
Chao, Jui-I
;
Chen, Chin-Piao
;
Cheng, Chia-Liang
The present invention provides a carrier including a nanodiamond (ND) particle and a linker covalently bound to the ND particle, in which the linker is presented by the formula: —R1—O(R2)m-Q-. In addition, the present invention further provides a carrier having an active unit covalently bound to the linker, in which the active unit is a drug, a vitamin or a biological molecule.
ANGLE-MEASURING METHOD AND ANGLE-MEASURING GYROSCOPE SYSTEM FOR IMPLEMENTING THE SAME
(2011-01-13)
CHEN, Tsung-Lin
;
CHI, Chien-Yu
An angle-measuring method includes: configuring a state observer to calculate a set of estimated signals based on a set of previously calculated estimated parameters; configuring the state observer to calculate a gain thereof using a dynamic equation associated with a gyroscope; configuring the state observer to calculate a set of currently calculated estimated parameters using the dynamic equation associated with the gyroscope based on the gain calculated by the state observer, a set of sensing signals generated by a sensing module, and the estimated signals calculated by the state observer; and configuring an angle calculator to calculate an angle of rotation of the gyroscope based on a position and a velocity in the currently calculated estimated parameters calculated by the state observer and a stiffness coefficient of the gyroscope. An angle-measuring gyroscope system that implements the angle-measuring method is also disclosed.
Surface doping is more beneficial than bulk doping to the photocatalytic activity of vanadium-doped TiO2
(2011-01-14)
Chang, Sue-min
;
Liu, Wei-szu
;
環境工程研究所
;
Institute of Environmental Engineering
In this study, we examined the effects of surface and bulk doping on the photocatalytic activity of vanadium (V)-doped TiO2 on the basis of charge trapping, separation, and interfacial transfer. Moreover, we characterized the microstructures and electronic structures of the two types of doped TiO2 and the chemical states of the doped V ions to elucidate the causes of the different physicochemical properties. The photocatalytic activity of the doped TiO2 was enhanced by 1.9 times when the V ions were doped only in the surface lattice at a surface V/Ti molar ratio of 3.0 x 10(-1), in contrast, bulk doping caused detrimental effects. Reduced species, including V3+ and V4+ ions, were formed in the interstitial anatase lattice. These impurities introduced occupied and unoccupied energy levels, which were close to and in the conduction band of TiO2, respectively. The V3+/V4+ ions within the TiO2 lattice inhibited charge diffusion to the surface through deep trapping. In contrast, the impurities present only in the surface lattice increased the number of surface trapped holes and facilitated the interfacial charge transfer from the photoactivated TiO2 to adsorbates. Heavy doping at the surface resulted in the formation of V2O5. The p-n junction between the TiO2 and V2O5 separated charge carriers and additionally promoted the photocatalytic activity of the surface-doped TiO2. (c) 2010 Elsevier B.V. All rights reserved.
Microwave-assisted carbofuran degradation in the presence of GAC, ZVI and H(2)O(2): Influence of reaction temperature and pH
(2011-01-14)
Remya, Neelancherry
;
Lin, Jih-Gaw
;
環境工程研究所
;
Institute of Environmental Engineering
Carbofuran degradation in microwave (MW)-assisted granular activated carbon (GAC)/zero-valent iron (ZVI)/hydrogen peroxide (H(2)O(2)) system(s) was investigated under different reaction temperatures, i.e. 30 degrees C, 50 degrees C and 80 degrees C, and at varying pHs, i.e. 2, 4, 6, 8 and 10. Batch experiments were conducted using a modified-MW reactor (750W power and 2450 MHz frequency) at 100 mg L(-1) carbofuran concentration. The lower MW-reaction temperatures, i.e. 30 degrees C and 50 degrees C, have produced poor carbofuran degradation efficiencies whereas complete carbofuran degradation (100%) was observed at 80 degrees C and pH 6 in all the systems, i.e. MW with GAC, ZVI and H(2)O(2). Under the similar conditions, insignificant carbofuran removal/degradation (2-24%) was observed in the presence of GAC/ZVI/H(2)O(2) without MW. On the other hand, the carbofuran degradation rate was accelerated under the alkaline pHs, i.e. pH 8 and 10 (at 80 degrees C), and 100% carbofuran degradation was observed within 10 min in all the MW-assisted systems. However, the complete carbofuran degradation was accomplished rapidly (5 min) in the MW-assisted GAC and ZVI systems under pH 10 and 80 degrees C. Carbofuran removal in the MW-assisted systems was modeled using the first-order reaction kinetics and a maximum removal rate constant of 4.17 min(-1) was obtained in the MW-assisted ZVI system. A maximum of 86% carbofuran mineralization was achieved in the MW-assisted GAC system via hydrolysis and the removal of carbamate group. The comparison of energy consumption in MW-assisted systems with other processes reveals that the MW-assisted process is highly efficient and cost-effective for carbofuran degradation and mineralization. (C) 2010 Elsevier B.V. All rights reserved.
Synthesis and applications of novel acceptor-donor-acceptor organic dyes with dithienopyrrole- and fluorene-cores for dye-sensitized solar cells
(2011-01-14)
Sahu, Duryodhan
;
Padhy, Harihara
;
Patra, Dhananjaya
;
Yin, Jen-Fu
;
Hsu, Ying-Chan
Four novel symmetrical organic dyes (S1-S4) configured with acceptor-donor-acceptor (A-D-A) structures containing electron donating fluorene (S1 and S2) and N-alkyl dithieno[3,2-b:2',3'-d]pyrrole (DTP) (S3 and S4) cores terminated with two anchoring cyanoacrylic acids (as electron acceptors) were synthesized and applied to dye-sensitized solar cells (DSSCs). The DSSC device based on S2 dye showed the best photovoltaic performance among S1-S4 dyes: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 76%, a short circuit current (J(SC)) of 12.27 mA/cm(2), an open circuit voltage (V(OC)) of 0.61 V. a fill factor (FF) of 0.63, and an overall power conversion efficiency (eta) of 4.73%. Besides, the utilization of chenodoxycholic acid (CDCA) as a co-adsorbent in the DSSC device based on S3 dye showed a significant improvement in its eta value (from 3.70% to 4.31%), which is attributed to the suppression of dye aggregation on TiO(2) surface and thus to increase the J(SC) value eventually. (C) 2010 Elsevier Ltd. All rights reserved.
Surface doping is more beneficial than bulk doping to the photocatalytic activity of vanadium-doped TiO(2)
(2011-01-14)
Chang, Sue-min
;
Liu, Wei-szu
;
環境工程研究所
;
Institute of Environmental Engineering
In this study, we examined the effects of surface and bulk doping on the photocatalytic activity of vanadium (V)-doped TiO(2) on the basis of charge trapping, separation, and interfacial transfer. Moreover, we characterized the microstructures and electronic structures of the two types of doped TiO(2) and the chemical states of the doped V ions to elucidate the causes of the different physicochemical properties. The photocatalytic activity of the doped TiO(2) was enhanced by 1.9 times when the V ions were doped only in the surface lattice at a surface V/Ti molar ratio of 3.0 x 10(-1), in contrast, bulk doping caused detrimental effects. Reduced species, including V(3+) and V(4+) ions, were formed in the interstitial anatase lattice. These impurities introduced occupied and unoccupied energy levels, which were close to and in the conduction band of TiO(2), respectively. The V(3+)/V(4+) ions within the TiO(2) lattice inhibited charge diffusion to the surface through deep trapping. In contrast, the impurities present only in the surface lattice increased the number of surface trapped holes and facilitated the interfacial charge transfer from the photoactivated TiO(2) to adsorbates. Heavy doping at the surface resulted in the formation of V(2)O(5). The p-n junction between the TiO(2) and V(2)O(5) separated charge carriers and additionally promoted the photocatalytic activity of the surface-doped TiO(2). (c) 2010 Elsevier B.V. All rights reserved.
Microwave-assisted carbofuran degradation in the presence of GAC, ZVI and H2O2: Influence of reaction temperature and pH
(2011-01-14)
Remya, Neelancherry
;
Lin, Jih-Gaw
;
環境工程研究所
;
Institute of Environmental Engineering
Carbofuran degradation in microwave (MW)-assisted granular activated carbon (GAC)/zero-valent iron (ZVI)/hydrogen peroxide (H2O2) system(s) was investigated under different reaction temperatures, i.e. 30 degrees C, 50 degrees C and 80 degrees C, and at varying pHs, i.e. 2, 4, 6, 8 and 10. Batch experiments were conducted using a modified-MW reactor (750W power and 2450 MHz frequency) at 100 mg L-1 carbofuran concentration. The lower MW-reaction temperatures, i.e. 30 degrees C and 50 degrees C, have produced poor carbofuran degradation efficiencies whereas complete carbofuran degradation (100%) was observed at 80 degrees C and pH 6 in all the systems, i.e. MW with GAC, ZVI and H2O2. Under the similar conditions, insignificant carbofuran removal/degradation (2-24%) was observed in the presence of GAC/ZVI/H2O2 without MW. On the other hand, the carbofuran degradation rate was accelerated under the alkaline pHs, i.e. pH 8 and 10 (at 80 degrees C), and 100% carbofuran degradation was observed within 10 min in all the MW-assisted systems. However, the complete carbofuran degradation was accomplished rapidly (5 min) in the MW-assisted GAC and ZVI systems under pH 10 and 80 degrees C. Carbofuran removal in the MW-assisted systems was modeled using the first-order reaction kinetics and a maximum removal rate constant of 4.17 min(-1) was obtained in the MW-assisted ZVI system. A maximum of 86% carbofuran mineralization was achieved in the MW-assisted GAC system via hydrolysis and the removal of carbamate group. The comparison of energy consumption in MW-assisted systems with other processes reveals that the MW-assisted process is highly efficient and cost-effective for carbofuran degradation and mineralization. (C) 2010 Elsevier B.V. All rights reserved.
Topological dynamics for multidimensional perturbations of maps with covering relations and Liapunov condition
(2011-01-15)
Li, Ming-Chia
;
Lyu, Ming-Jiea
;
應用數學系
;
Department of Applied Mathematics
In this paper, we study topological dynamics of high-dimensional systems which are perturbed from a continuous map on R(m) x R(k) of the form (1(x), g(x, y)). Assume that f has covering relations determined by a transition matrix A. If g is locally trapping, we show that any small C(0) perturbed system has a compact positively invariant set restricted to which the system is topologically semi-conjugate to the one-sided subshift of finite type induced by A. In addition, if the covering relations satisfy a strong Liapunov condition and g is a contraction, we show that any small C(1) perturbed homeomorphism has a compact invariant set restricted to which the system is topologically conjugate to the two-sided subshift of finite type induced by A. Some other results about multidimensional perturbations of f are also obtained. The strong Liapunov condition for covering relations is adapted with modification from the cone condition in Zgliczynski (2009) [11]. Our results extend those in Juang et al. (2008) [1], Li et al. (2008) [2]. Li and Malkin (2006) [3]. Misiurewicz and Zgliczynski (2001) [4] by considering a larger class of maps f and their multidimensional perturbations, and by concluding conjugacy rather than entropy. Our results are applicable to both the logistic and Henon families. (C) 2010 Elsevier Inc. All rights reserved.
Study of the internal quantum efficiency of InGaN/GaN UV LEDs on patterned sapphire substrate using the electroluminescence method
(2011-01-15)
Wang, C. H.
;
Ke, C. C.
;
Chiu, C. H.
;
Li, J. C.
;
Kuo, H. C.
Internal quantum efficiency (IQE) of InGaN/GaN UV LEDs with patterned sapphire substrates (PSS) was investigated using electroluminescence (EL) and photoluminescence (PL) methods. The physical mechanisms that affect temperature-dependent EL efficiency as a function of injected carrier density were deduced. In order to reduce the density of non-radiative recombination centers to improve quantum efficiency, improvement of crystal quality and reduction in the number of defects are necessary. PSS LEDs showed better EL characteristics than non-PSS LEDs because of the improved epitaxial quality. Contrary to PL IQE, EL IQE was significantly affected by carrier injection efficiency, especially at low temperature when high bias voltage was applied to the p-n junction. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
A survey of energy efficient MAC protocols for IEEE 802.11 WLAN
(2011-01-15)
Tsao, Shiao-Li
;
Huang, Chung-Huei
;
資訊工程學系
;
Department of Computer Science
In recent years, IEEE 802.11 wireless local area networks (WLANs) have been widely deployed, and more and more mobile devices have built-in WLAN interfaces. However, WEAN employs the carrier sense multiple access with collision avoidance (CSMA/CA) medium access control (MAC) protocol, which consumes a significant portion of the energy resources of a mobile device. Hence, minimizing the energy consumption of the WLAN interface in mobile devices has recently attracted considerable interest in both academia and industry. This article provides a survey and an experimental study of the energy consumption issues and energy-efficient technologies of the MAC protocol in IEEE 802.11 WLAN. (C) 2010 Elsevier B.V. All rights reserved.
Synthesis and characterization of semicarbazone of p-hydroxy-3-methoxy acetophenone (SPH3MA) single crystal
(2011-01-15)
Janarthanan, S.
;
Rajan, Y. C.
;
Umarani, P. R.
;
Selvakumar, S.
;
Pandi, S.
Single crystals of semicarbazone of p-hydroxy-3-methoxy acetophenone (SPH3MA) were grown by a slow evaporation solution growth technique at room temperature. This is the first report in the literature on the crystallization of SPH3MA. The cell parameters of the grown crystals were estimated by single crystal X-ray diffraction analysis. The various planes of reflection were identified from the XRD powder pattern. The presence of functional groups was identified from FTIR and (1)H NMR. The results were found to be in accordance with the structure of the crystal. The formation of charge transfer complex was confirmed by UV-vis-NIR spectroscopy. The thermal stability of the grown crystal was studied by thermal analysis. (C) 2010 Elsevier B.V. All rights reserved.
Octave-spanning carrier-envelope phase stabilized visible pulse with sub-3-fs pulse duration
(2011-01-15)
Okamura, Kotaro
;
Kobayashi, Takayoshi
;
電子物理學系
;
Department of Electrophysics
The visible second harmonic of the idler output from a noncollinear optical parametric amplifier was compressed using adaptive dispersion control with a deformable mirror. The amplifier was pumped by and seeded in the signal path by a common 400 nm second-harmonic pulse from a Ti:sapphire regenerative amplifier. Thus, both the idler output and the second harmonic of the idler were passively carrier-envelope phase stabilized. The shortest pulse duration achieved was below 3 fs. (C) 2011 Optical Society of America
Assessment of interface roughness during plasma etching through the use of real-time ellipsometry
(2011-01-15)
Han, Chien-Yuan
;
Lai, Chien-Wen
;
Chao, Yu-Faye
;
Leou, Ke-Ciang
;
Lin, Tsang-Lang
Real-time in situ ellipsometry was used to investigate the etching of SiO(2)/silicon wafers with a high concentration of Cl(2). We monitored the temporal trajectory of the ellipsometric parameter Delta and then selected several points for ex situ study using atomic force microscopy (AFM). There was a clearly observable transition period in the trajectory near the endpoint of the SiO(2)/Si interface. We studied the relationship between the ellipsometric parameter Delta and the same point in the AFM ex situ measurements. Three stages, thin film, the interface layer, and the substrate, were analyzed in this work. (C) 2010 Elsevier B.V. All rights reserved.
Material characteristics of InGaN based light emitting diodes grown on porous Si substrates
(2011-01-15)
Deng, Dongmei
;
Chiu, Ching-Hsueh
;
Kuo, Hao-Chung
;
Chen, Peng
;
Lau, Kei May
InGaN/GaN multiple quantum wells light emitting diodes (LEDs) with 2 mu m thick crack-free GaN buffer layers were grown on porous Si substrates by metalorganic chemical vapor deposition. The material properties of LEDs grown on porous Si were studied in comparison with LEDs grown on grid-patterned Si. The (1 0 (1) over bar 5) asymmetric reciprocal space mapping (RSM) results indicate that LEDs grown on porous Si have less lattice tilt or distortion than those grown on grid-patterned Si. Both RSM and micro-photoluminescence (micro-PL) measurements suggest that multiple quantum wells grown on porous Si are less stressed. Mechanisms behind this partial strain relaxation are discussed. (C) 2010 Elsevier B.V. All rights reserved.