Browsing by Issue Date, starting with "2008-08-26"

Now showing 1 - 20 of 54791

Solar-pumped active device
(2008-08-26)
Chi
;
Sien
;
Chen
;
Nan-Kuang
;
Shy
The present invention provides a solar-pumped active device which utilizes a holographic antenna grating on a solar energy silicon substrate to select specific diffracted wavelength and couple pump wavelength in an approximately vertical way and converge the pump wavelength to excite an optical gain medium so that an optical amplifier or a laser can be obtained. The present invention requires no big size and is flexible over the surface shape and is suitable for free space optical communications on the ground and satellite optical communications. It means that the holographic antenna grating can be applied on the top floor of a building or on the glass surface of an outer wall. If it is applied to a satellite, the present invention can be deposited on a solar energy cell substrate to form a high optical amplification so that not only the electricity required in satellite optical communications can be reduced, but also a high-speed and large capacity of data can be transferred between satellites.
Synthesis and characterization of amorphous octakis-functionalized polyhedral oligomeric silsesquioxanes for polymer nanocomposites
(2008-08-26)
Sheen, Yuung-Ching
;
Lu, Chu-Hua
;
Huang, Chih-Feng
;
Kuo, Shiao-Wei
;
Chang, Feng-Chih
We have synthesized the polyhedral oligomeric silsesquioxane (POSS) derivatives OS-POSS and OA-POSS through the hydrosilylation of styrene and 4-acetoxystyrene, respectively, with octakis(dimethylsiloxy)-silsesquioxane (Q(8)M(8)(H)). We then prepared OP-POSS through acetoxyl hydrazinolysis of OA-POSS with hydrazine monohydrate. The chemical structures of these POSS derivatives were characterized using FTIR and H-1 NMR spectroscopy and MALDI-TOF mass spectrometry. Unlike Q(8)M(8)(H), which is crystalline, these three hydrosilylated POSS derivatives are liquids at 25 degrees C. Through DSC and XRD analyses, we found that they exhibit polymer-like glass transitions and amorphous halos. These octakis-functionalized POSS derivatives can be regarded as amorphous glasses possessing low glass transition temperatures, the values of which depend on the intermolecular interactions of their outer organic groups. To investigate the dispersion of these POSS derivatives in polymer nanocomposites, we blended OS-POSS, OA-POSS, and OP-POSS with polystyrene, poly(4-acetoxystyrene), and poly(4-vinylpyridine), respectively, and investigated the effects of the resulting intermolecular aromatic hydrophobic, dipole-dipole, and hydrogen-bonding interactions, respectively. Dipole-dipole interactions provided the best dispersion of OA-POSS in poly(4-acetoxystyrene), in which the POSS-polymer intermolecular interactions were of similar strength to the POSS-POSS interactions. (C) 2008 Elsevier Ltd. All rights reserved.
Application of m-CNTs/NaClO4/Ppy to a fast response, room working temperature ethanol sensor
(2008-08-28)
Wu, Ren-Jang
;
Huang, Yu-Ching
;
Yu, Ming-Ru
;
Lin, Tzu Hsuan
;
Hung, Shih-Lin
A new blended material, m-CNTs/NaClO4/Ppy, was developed as a gas sensor to detect ethanol concentrations at room temperature. The sensing material polypyrrole (Ppy) was synthesized in situ by UV-photo-polymerization. The multiwall carbon nanotubes (m-CNTs) added enhanced the short-term repeatability of the Ppy-sensing material. The relative resistance variation (R-ethanol/R-air) of mCNTs/NaClO4/Ppy was 1.193 when exposed to ethanol of 30,000 ppm. The sensor response and recovery times (both 20s) were very short to this concentration. An unstable baseline of the sensor was explained by theoretical calculation of molecular dynamics made for ethanol adsorption on polypyrrole, which revealed formation of a new bond, N-H center dot center dot center dot O. Adsorption energy decreased with increasing the number of ethanol molecules adsorbed and was 0.8 kcal/mol at eight adsorbed molecules. Sensor responses of three different Ppy samples were measured to ethanol concentrations of 18,000-40,000 ppm. (C) 2008 Elsevier B.V. All rights reserved.
Fine-grained bandwidth control arbiter and the method thereof
(2008-08-28)
Huang, Juinn-Dar
;
Lin, Bu-Ching
;
Lee, Geeng-Wei
;
Jou, Jing-Yang
A fine-grained bandwidth control arbiter manages the shared bus usage of the requests of the masters which have real-time and/or bandwidth requirements, moreover, the masters are preset a ticket respectively. The arbiter consists of three components, a real-time handler, a bandwidth regulator, and a lottery manager with tuned weight. The real-time handler grants the most urgent request. The bandwidth regulator handles the bandwidth allocation and blocks the requests of masters that have met the bandwidth requirement. The lottery manager with tuned weight stochastically grants one of the contending masters according to the ticket assignment.
Maximal sets of Hamilton cycles in Dn
(2008-08-28)
Pu, Liqun
;
Fu, Hung-Lin
;
Shen, Hao
;
應用數學系
;
Department of Applied Mathematics
In this paper, we prove that there exists a maximal set of in directed Hamilton cycles in D(n) if and only if [n/2] <= m <= n -1 for n >= 7. (C) 2007 Elsevier B.V. All rights reserved.
Identification and characterization of two novel cytosolic sulfotransferases, SULT1 ST7 and SULT1 ST8, from zebrafish
(2008-08-29)
Liu, Tzu-An
;
Bhuiyan, Shakhawat
;
Snow, Rhodora
;
Yasuda, Shin
;
Yasuda, Tomoko
Cytosolic sulfotransferases (SULTs) constitute a family of Phase 11 detoxification enzymes that are involved in the protection against potentially harmful xenobiotics as well as the regulation and homeostasis of endogenous compounds. Compared with humans and rodents, the zebrafish serves as an excellent model for studying the role of SULTs in the detoxification of environmental pollutants including environmental estrogens. By searching the expressed sequence tag database, two zebrafish cDNAs encoding putative SULTs were identified. Sequence analysis indicated that these two putative zebrafish SULTs belong to the SULT1 gene family. The recombinant form of these two novel zebrafish SULTs, designated SULT1 ST7 and SULT1 ST8, were expressed using the pGEX-2TK glutathione S-transferase (GST) gene fusion system and purified from transformed BL21 (DE3) cells. Purified GST-fusion protein form of SULT1 ST7 and SULT1 ST8 exhibited strong sulfating activities toward environmental estrogens, particularly hydroxylated polychlorinated biphenyls (PCBs), among various endogenous and xenobiotic compounds tested as substrates. pH-dependence experiments showed that SULT1 ST7 and SULT1 ST8 displayed pH optima at 6.5 and 8.0, respectively. Kinetic parameters of the two enzymes in catalyzing the sulfation of catechin and chlorogenic acid as well as 3-chloro-4-biphenylol were determined. Developmental expression experiments revealed distinct patterns of expression of SULT1 ST7 and SULT1 ST8 during embryonic development and throughout the larval stage onto maturity. (C) 2008 Elsevier B.V. All rights reserved.
Semi-analytical solution for a slug test in partially penetrating wells including the effect of finite-thickness skin
(2008-08-30)
Yeh, Hund-Der
;
Chen, Yen-Ju
;
Yang, Shaw-Yang
;
環境工程研究所
;
Institute of Environmental Engineering
This paper presents a new semi-analytical solution for a slug test in a well partially penetrating a confined aquifer, accounting for the skin effect. This solution is developed based on the solution for a constant-flux pumping test and a formula given by Peres and co-workers in 1989. The Solution agrees with that of Cooper and co-workers and the KGS model when the well is fully penetrating. The present Solution can be applied to simulate the temporal and spatial head distributions in both the skin and formation zones. It can also be used to demonstrate the influences of skin type or skin thickness on the well water level and to estimate the hydraulic parameters of the skin and formation zones using a least-squares approach. The results of this study indicate that the determination of hydraulic conductivity using a conventional slug-test data analysis that neglects the presence of a skin zone will give an incorrect result if the aquifer has a skin zone. Copyright (C) 2008 John Wiley &, Sons. Ltd.
Study of trap states in polyfluorene based devices by using TSC technique
(2008-08-30)
Renaud, C.
;
Huang, C. H.
;
Lee, C. W.
;
Le Rendu, P.
;
Nguyen, T. P.
The trap states in poly(9,9-dihexylfluorene-co-N,N-di(9,9-dihexyl-2-fluorenyl)-N-phenylamine) (PF-N-Ph) based light emitting diodes have been investigated by using the thermally stimulated current (TSC) technique in the temperature range of 90-320 K. The studied structure consisted of indium-tin-oxide/polyethylene-dioxythiophene: polystyrene-sulfonate/PF-N-Ph/Al. Four traps centers denoted as A, B, C, and D trap types have been identified with densities in the range of 10(16)-10(17) cm(-3). Study of the dependence of TSC characteristics on the device polarity suggested that the A, C and D type traps are electron traps while the B type traps are hole traps. They can be described by Gaussian distributions centered on mean trap levels. (c) 2008 Elsevier B.V. All rights reserved.
反哲學的讀書論：三木清〈讀書論〉
(國立陽明交通大學出版社, 2008-09-01)
子安宣邦
;
馮啓斌
High field emission efficiency surface conduction electron emitters
(2008-09-01)
Li, Yiming
;
Chao, Hsueh-Yung
;
Lo, Hsiang-Yu
;
電信工程研究所
;
Institute of Communications Engineering
Two different surface conduction electron-emitter (SCE) structures with the nanogap of 90 nm wide fabricated by hydrogen embrittlement (HE) and focused ion beam techniques are simulated for the first time. We employ a three-dimensional particle-in-cell method coupling with finite-difference time-domain scheme to simulate the property of electron emission in these SCEs. Our calibrated simulation predicts high emission efficiency of the SCE structure which is fabricated by HE. Compared with the other SCE structure, it is observed that the proposed structure possesses low power consumption at the fixed emission current when the width of nanogap becomes narrower. The current-voltage characteristics including conducting mechanisms are investigated and explained.
Three-dimensional simulation of field emission triode structure using carbon-nanotube emitters
(2008-09-01)
Li, Yiming
;
Yeh, Ta-Ching
;
電信工程研究所
;
Institute of Communications Engineering
Field emission (FE) triode arrays with the anodic aluminum oxide (AAO) template carbon nanotubes (CNTs) as the field emitters are successfully fabricated and analyzed. Both the experimental measurement and numerical calculation are conducted to examine the electron conduction properties of AAO-CNTs. Using a three-dimensional finite-difference time-domain particle-in-cell method, a set of Maxwell equations and Lorentz equation is solved self-consistently, where the FE current is computed with Fowler-Nordheim equation. We explore the FE characteristics of AAO-CNTs in the triode structure. After calibration with the measured data, we study the evolution of current density and the convergence of the electron beams on anode plate with different gate voltages, anode heights, and SiO2 thickness. The current density and focus performance maintain a trade-off relationship, where a larger current density accompanies more divergent electron beam.
Effective Decap Insertion in Area-Array SoC Floorplan Design
(2008-09-01)
Lu, Chao-Hung
;
Chen, Hung-Ming
;
Liu, Chien-Nan Jimmy
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
As VLSI technology enters the nanometer era, supply voltages continue to drop due to the reduction of power dissipation, but it makes power integrity problems even worse. Employing decoupling capacitances (decaps) in floorplan stage is a common approach to alleviating supply noise problems. Previous researches overestimate the decap budget and do not fully utilize the empty space of the floorplan. A floorplan usually has a lot of available space that can be used to insert the decap without increasing the floorplan area. Therefore, the goal of this work is to develop a better model to calculate the required decap to solve the power supply noise problem in area-array based designs, and increase the usage of available space in the floorplan to reduce the area overhead caused by decap insertion. The experimental results of this work are encouraging. Compared with previous approaches, our methodology reduces 38% of the decap budget in average for MCNC benchmarks but can still meet the power supply noise requirements. The final floorplan areas with decap are also smaller than the numbers reported in previous works.
Optical Properties of Ce-Doped ZnO Nanowires Directionally Grown by Hydrothermal Method
(2008-09-01)
Chen, Y. S.
;
Tseng, T. Y.
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Well directionally grown Ce-doped ZnO nanowires were successfully synthesized by a simple hydrothermal method. The Ce dopant plays a key role in evolving the morphology, affecting the crystalline size, and forming the uniform nanostructure of the ZnO nanowires. The amount of Ce dopant in the ZnO nanowires also affects the regions of blue-shift in the UV and green emission peaks and the intensities of emission peaks based on the cathodoluminescence spectra of the nanowires. Moreover, the effect of Ce doping amount on the microstructure of the nanowires is also presented.
A WSN-Based Intelligent Light Control System Considering User Activities and Profiles
(2008-09-01)
Pan, Meng-Shiuan
;
Yeh, Lun-Wu
;
Chen, Yen-Ann
;
Lin, Yu-Hsuan
;
Tseng, Yu-Chee
Recently, wireless sensor networks (WSNs) have been widely discussed in many applications. In this paper, we propose a WSN-based intelligent light control system for indoor environments. Wireless sensors are responsible for measuring current illuminations. Two kinds of lighting devices, namely, whole lighting and local lighting devices, are used to provide background and concentrated illuminations, respectively. Users may have various illumination requirements according to their activities and profiles. An illumination requirement is as the combination of background and concentrated illumination demands and users' locations. We consider two requirement models, namely, binary satisfaction and continuous satisfaction models, and propose two decision algorithms to determine the proper illuminations of devices and to achieve the desired optimization goals. Then, a closed-loop device control algorithm is applied to adjust the illumination levels of lighting devices. The prototyping results verify that our ideas are practical and feasible.
A compact RF CMOS modeling for accurate high-frequency noise simulation in sub-100-nm MOSFETs
(2008-09-01)
Guo, Jyh-Chyurn
;
Lin, Yi-Min
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A compact RF CMOS model incorporating an improved thermal noise model is developed. Short-channel effects (SCEs), substrate potential fluctuation effect, and parasitic-resistance-induced excess noises were implemented in analytical formulas to accurately simulate RF noises in sub-100-nm MOSFETs. The intrinsic noise extracted through a previously developed lossy substrate de-embedding method and calculated by the improved noise model can consistently predict gate length scaling effects. For 65- and 80-nm n-channel MOS with f(T) above 160 and 100 GHz, NF(min) at 10 GHz can be suppressed to 0.5 and 0.7 dB, respectively. Drain current noise S(id) reveals an apparently larger value for 65-nm devices than that for 80-nm devices due to SCE. On the other hand, the shorter channel helps reduce the gate current noise S(ig) attributed to smaller gate capacitances. Gate resistance R(g)-induced excess noise dominates in S(ig) near one order higher than the intrinsic gate noise that is free from R(g) for 65-nm devices. The compact RF CMOS modeling can facilitate high-frequency noise simulation accuracy in nanoscale RF CMOS circuits for low-noise design.
Relevance feedback for category search in music retrieval based on semantic concept learning
(2008-09-01)
Shan, Man-Kwan
;
Chiang, Meng-Fen
;
Kuo, Fang-Fei
;
資訊工程學系
;
Department of Computer Science
Traditional content-based music retrieval systems retrieve a specific music object which is similar to what a user has requested. However, the need exists for the development of category search for the retrieval of a specific category of music objects which share a common semantic concept. The concept of category search in content-based music retrieval is subjective and dynamic. Therefore, this paper investigates a relevance feedback mechanism for category search of polyphonic symbolic music based on semantic concept learning. For the consideration of both global and local properties of music objects, a segment-based music object modeling approach is presented. Furthermore, in order to discover the user semantic concept in terms of discriminative features of discriminative segments, a concept learning mechanism based on data mining techniques is proposed to find the discriminative characteristics between relevant and irrelevant objects. Moreover, three strategies, the Most-Positive, the Most-Informative, and the Hybrid, to return music objects concerning user relevance judgments are investigated. Finally, comparative experiments are conducted to evaluate the effectiveness of the proposed relevance feedback mechanism. Experimental results show that, for a database of 215 polyphonic music objects, 60% average precision can be achieved through the use of the proposed relevance feedback mechanism.
眞實世界的消失：布希亞的現身
(國立陽明交通大學出版社, 2008-09-01)
S. Loehr
;
洪菁勵
Membrane translocation of small GTPase Rac1 and activation of STAT1 and STAT3 in pacing-induced sustained atrial fibrillation
(2008-09-01)
Tsai, Chia-Ti
;
Lin, Jiunn-Lee
;
Lai, Ling-Ping
;
Lin, Chih-Sheng
;
Huang, Sheoi K. Stephen
BACKGROUND Angiotensin II and its downstream mitogen-activated protein kinase signaling pathways are involved in the pathogenesis of AF. Pro-inflammatory JAK/STAT is another downstream signaling pathway of Angiotensin II, and its status in AF remains unknown. OBJECTIVE The aim of this study was to characterize the status of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways in pacing-induced sustained atrial fibrillation (AF). METHODS AF was induced by atrial pacing at 600/min in 10 adult pigs (AF group), while 10 sham-operated pigs served as the control group. RESULTS Significant structural and inflammatory changes were noted in the AF group. Atrial tissue angiotensin II level was elevated and STAT1 and STAT3 were activated in the AF group. Nuclear translocation of activated STAT3 and binding to STAT3 consensus DNA sequence were also increased in the AF group. Rac1, the molecular target of statin, which mediates the activation of STAT3 by angiotensin II, was also activated in the AF group. The tissue levels of interteukin-6, leukemia inhibitory factor (LIF) and cardiotrophin-1 (CT-1), which are known to activate STATs through membrane gp130 and JAKs, were not increased in the AF group. Membrane gp130 and JAKs were also not activated in the AF group. CONCLUSION Activated angiotensin II/Rac1/STAT may be associated with or perhaps contribute to the structural and inflammatory changes in pacing-induced sustained trial fibrillation. It may further imply the therapeutic option of combination of angiotensin receptor blocker and statin.
Optimal design of triple-gate devices for high-performance and low-power applications
(2008-09-01)
Chiang, Meng-Hsueh
;
Lin, Jeng-Nan
;
Kim, Keunwoo
;
Chuang, Ching-Te
;
電子工程學系及電子研究所
Pragmatic design of triple-gate (TG) devices is presented by considering corner effects, short-channel effects, and channel-doping profiles. A novel TG MOSFET structure with a polysilicon gate process is proposed using asymmetrical (n(+)/p(+)) polysilicon gates. CMOS-compatible V(T)'s for high-performance circuit applications can be achieved for both nFET and pFET. The superior subthreshold characteristics and device performance are analyzed and validated by 3-D numerical simulations. Comparisons of device characteristics with a midgap metal gate are presented.
Spin Hall effect in a Josephson contact
(2008-09-01)
Mal'shukov, A. G.
;
Chu, C. S.
;
電子物理學系
;
Department of Electrophysics
The spin Hall effect on the Josephson tunneling through a two-dimensional normal contact with a spin-orbit split conduction band has been studied in the diffusive regime and at the zero electric bias. Linearized Usadel equations for triplet components of the pairing function in the presence of intrinsic spin-orbit interaction have been derived. These equations have been employed for analysis of the spin Hall effect induced by the super-current. We predict that a nondissipative out-of-plane spin Hall polarization accumulates at lateral edges and an in-plane polarization is induced throughout the entire normal region. At the same time, in contrast to the spin Hall effect in normal systems, the spin current is absent in the considered case of the stationary Josephson effect.