Browsing by Issue Date, starting with "2011-01-13"

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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.
Epitaxial growth of titanium oxycarbide on MgO (001) substrates by pulsed laser deposition
(2011-01-15)
Do, Hien
;
Yen, Tzu-Chun
;
Tian, Chih-Sheng
;
Wu, Yue-Han
;
Chang, Li
Epitaxial TiC(x)O(y) thin films were grown on MgO (0 0 1) substrates by using pulsed laser deposition method. High-resolution X-ray diffraction and transmission electron microscopy were used to examine crystallinity and microstructure of epitaxial TiC(x)O(y) film on MgO. The chemical composition of the film is determined to be x similar to 0.47 and y similar to 0.69 by X-ray photoelectron spectroscopy. Atomic force microscopy revealed that the surface of TiC(x)O(y) film is very smooth with roughness of 0.18 nm. The resistivity of the TiC(x)O(y) film measured by four-point-probe method was about 137 mu Omega cm. (C) 2010 Elsevier B.V. All rights reserved.
Label free sub-picomole level DNA detection with Ag nanoparticle decorated Au nanotip arrays as surface enhanced Raman spectroscopy platform
(2011-01-15)
Lo, Hung-Chun
;
Hsiung, Hsin-I
;
Chattopadhyay, Surojit
;
Han, Hsieh-Cheng
;
Chen, Chia-Fu
Label free optical sensing of adenine and thymine oligonucleotides has been achieved at the sub-picomole level using self assembled silver nanoparticles (AgNPs) decorated gold nanotip (AuNT) arrays. The platform consisting of the AuNTs not only aids in efficient bio-immobilization, but also packs AgNPs in a three dimensional high surface area workspace, assisting in surface enhanced Raman scattering (SERS). The use of sub-10 nm AgNPs with optimum inter-particle distance ensures amplification of the chemically specific Raman signals of the adsorbed adenine, thymine, cytosine and guanine molecules in SERS experiments. High temporal stability of the Raman signals ensured reliable and repeatable DNA detection even after three weeks of ambient desk-top conservation. This facile architecture, being three dimensional and non-lithographic, differs from conventional SERS platforms. (C) 2010 Elsevier B.V. All rights reserved.
Nonpolar a-plane GaN grown on r-plane sapphire using multilayer AlN buffer by metalorganic chemical vapor deposition
(2011-01-15)
Chiang, C. H.
;
Chen, K. M.
;
Wu, Y. H.
;
Yeh, Y. S.
;
Lee, W. I.
Mirror-like and pit-free non-polar a-plane (11-20) GaN films are grown on r-plane (1-102) sapphire substrates using metalorganic chemical vapor deposition (MOCVD) with multilayer high-low-high temperature AlN buffer layers. The buffer layer structure and film quality are essential to the growth of a flat, crack-free and pit-free a-plane GaN film. The multilayer AlN buffer structure includes a thin low-temperature- deposited AlN (LT-AlN) layer inserted into the high-temperature-deposited AlN (HT-AlN) layer. The results demonstrate that the multilayer AlN buffer structure can improve the surface morphology of the upper a-plane GaN film. The grown multilayer AlN buffer structure reduced the tensile stress on the AlN buffer layers and increased the compressive stress on the a-plane GaN film. The multilayer AlN buffer structure markedly improves the surface morphology of the a-plane GaN film, as revealed by scanning electron microscopy. The effects of various growth V/III ratios was investigated to obtain a-plane GaN films with better surface morphology. The mean roughness of the surface was 1.02 nm, as revealed by atomic force microscopy. Accordingly, the multilayer AlN buffer structure improves the surface morphology and facilitates the complete coalescence of the a-plane GaN layer. (C) 2010 Elsevier B.V. All rights reserved.
Using silicon nanowire devices to detect adenosine triphosphate liberated from electrically stimulated HeLa cells
(2011-01-15)
Chen, C. C.
;
Chen, Y-Z
;
Huang, Y-J
;
Sheu, J-T
;
材料科學與工程學系奈米科技碩博班
In this study, we used a biosensor chip featuring Abl tyrosine kinase-modified silicon nanowire field-effect transistors (SiNW-FETs) to detect adenosine triphosphate (ATP) liberated from HeLa cells that had been electrically stimulated. Cells that are cultured in high-ionic-strength media or buffer environments usually undermine the sensitivity and selectively of SiNW-FET-based sensors. Therefore, we first examined the performance of the biosensor chip incorporating the SiNW-FETs in both low- and high-ionic-strength buffer solutions. Next, we stimulated, using a sinusoidal wave (1.0V, 50 Hz, 10 min), HeLa cells that had been cultured on a cell-culture chip featuring interdigitated electrodes. The extracellular ATP concentration increased by ca. 18.4-fold after electrical stimulation. Finally, we detected the presence of extracellular ATP after removing a small amount of buffer solution from the cell-cultured chip and introducing it into the biosensor chip. (C) 2010 Elsevier B.V. All rights reserved.
分心腦波量測分析方法及其應用系統
(2011-01-16)
林進燈
;
柯立偉
;
陳世安
;
邱添丁
;
王俞凱
本發明提供一種分心腦波量測分析方法及其應用系統，其係透過腦波量測與分析系統取得車輛駕駛者的數個腦波訊號，再使用主成分分析法(PCA)、獨立成分分析法(ICA)與傅立葉轉換對數個腦波訊號進行演算分析，以獲得一腦波誘發電位與/或觀測事件相關頻譜擾動(ERSP)圖表，分析腦波誘發電位與/或觀測事件相關頻譜擾動圖表是否有能量改變，如果是，則表示受測者正處於分心狀態，則由回饋系統提醒受測者，以避免受測者因分心所可能產生的反應延遲；以及如果否，則表示受測者無分心，繼續受測者的腦波量測與分析。