Browsing by Issue Date, starting with "2011-07-30"

Now showing 1 - 20 of 40809

An improved genetic programming to SSM/I estimation typhoon precipitation over ocean
(2011-07-30)
Chen, Li
;
Yeh, Keh-Chia
;
Wei, Hsiao-Ping
;
Liu, Gin-Rong
;
土木工程學系
This article proposes an improved multi-run genetic programming (GP) and applies it to estimate the typhoon rainfall over ocean using multi-variable meteorological satellite data. GP is a well-known evolutionary programming and data mining method used to automatically discover the complex relationships among nonlinear systems. The main advantage of GP is to optimize appropriate types of function and their associated coefficients simultaneously. However, the searching efficiency of traditional GP can be decreased by the complex structure of parse tree to represent the multiple input variables. This study processed an improvement to enhance escape ability from local optimums during the optimization procedure. We continuously run GP several times by replacing the terminal nodes at the next run with the best solution at the current run. The current method improves GP, obtaining a highly nonlinear meaningful equation to estimate the rainfall. In the case study, this improved GP (IGP) described above combined with special sensor microwave imager (SSM/I) seven channels was employed. These results are then verified with the data from four offshore rainfall stations located on islands around Taiwan. The results show that the IGP generates sophisticated and accurate multi-variable equation through two runs. The performance of IGP outperforms the traditional multiple linear regression, back-propagated network (BPN) and three empirical equations. Because the extremely high values of precipitation rate are quite few and the number of zero values (no rain) is very large, the underestimations of heavy rainfall are obvious. A simple genetic algorithm was therefore used to search for the optimal threshold value of SSM/I channels, detecting the data of no rain. The IGP with two runs, used to construct an appropriate mathematical function to estimate the precipitation, can obtain more favourable results from estimating extremely high values. Copyright. (C) 2011 John Wiley & Sons, Ltd.
Antibodies against Helicobacter pylori heat shock protein 60 aggravate HSP60-mediated proinflammatory responses
(2011-08-01)
Liao, Kuang-Wen
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Lin, Chen-Si
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Chen, Wen-Liang
;
Yang, Chu-Ting
;
Lin, Ching-Min
Anti-Helicobacter pylori heat shock protein 60 (HpHSP60) antibodies are Usually found in H. pylori-infected patients and are known to be associated with the progression of gastric diseases. However, the effects of these antibodies on the functions of HpHSP60 have not been identified. This study aims to investigate the effects of the interaction between anti-HSP60 antibodies and HpHSP60 on inflammatory responses. Anti-HpHSP60 polyclonal sera and monoclonal antibodies (mAbs) were produced to evaluate their effects on HpHSP60-induced IL-8 and TNF-alpha activity. The results indicated that anti-HpHSP60 polyclonal sera collected from patients infected with H. pylori or from rabbit and mice immunized with HpHSP60 could significantly enhance HpHSP60-mediated IL-8 and TNF-alpha secretion from monocytic THP-1 cells. Similar effects were also found with anti-HpHSP60 mAbs. Further analysis revealed that this phenomenon was only carried out by anti-HpHSP60 antibody but not by other non-specific mAbs. Moreover, the non-specific mAbs decreased the synergism of HpHSP60 and anti-HpHSP60 mAbs in proinflammatory cytokine induction. Herein, we have examined the role of anti-HpHSP60 antibody in host immune responses for the first time. This study demonstrated that H. pylori HSP60/mAbs could modulate helico-bacterial pathogenesis by increasing IL-8 and TNF-alpha production. The pathogen-specific antibodies may execute potential immune functions rather than recognize or neutralize microbes. (C) 2011 Elsevier Ltd. All rights reserved.
Accessing Manufacturing Yield for Gamma Wafer Sawing Processes in COG Packaging
(2011-08-01)
Pearn, Wen-Lea
;
Tai, Yu-Ting
;
Huang, Kai-Bin
;
Ku, Pin-Lun
;
工業工程與管理學系
The technology of thin film transistor liquid crystal display (LCD) has become more popular due to great demand for worldwide consumer electronic products. Driver integrated circuit (IC) is a critical device that is embedded sophisticated circuits to drive panels. Since narrow border design on display products is current trend, dimensions of driver ICs are shrunken. In the high-density LCD driver ICs, the operation of wafer sawing is essential and needs accurate yield assessment. However, inevitable process variance changes could arise from sawing machine, material, operation, and workmanship, and may not be detected within short time. Conventionally, manufacturing yield is evaluated applying typical yield measure index method under the assumptions that the processes are stable and normal. To assess manufacturing yield for Gamma wafer sawing processes more accurately, we present a modified yield measure index method. Using the proposed method, the magnitudes of the undetected variance change, which are functions of the detection power of the S(2) chart, are incorporated into the evaluation of manufacturing yield. In addition, we demonstrate, mathematically, that the accommodation would not be affected by the scale parameter of Gamma distribution. For illustration purpose, a real-world case in a wafer sawing factory which is located on the Science-based Industrial Park in Hsinchu, Taiwan, is presented.
鎖相迴路頻率合成器及其迴路鎖定方法
(2011-08-01)
陳巍仁
;
李彥緯
一種鎖相迴路頻率合成器及其迴路鎖定方法，該鎖相迴路頻率合成器包括參考路徑和差調變器回授電路、耦接於該參考路徑和差調變器回授電路的輸出端之參考相位積分電路、耦接於該參考相位積分電路的輸出端之相位/頻率偵測器、耦接於該相位/頻率偵測器的輸出端及該參考路徑和差調變器回授電路的輸入端之迴路濾波器、耦接於該迴路濾波器輸出端之振盪器、以及耦接於該振盪器的輸出端及該相位/頻率偵測器的輸入端之回授相位積分電路。藉由本發明鎖相迴路頻率合成器，使振盪器能產生對應參考訊號之頻率訊號，並具有抗雜訊、提高解析度及易於整合之功效。
Low-Power and Highly Reliable Multilevel Operation in ZrO(2) 1T1R RRAM
(2011-08-01)
Wu, Ming-Chi
;
Lin, Yi-Wei
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Jang, Wen-Yueh
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Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
The Ti/ZrO(2)/Pt resistive memory devices with one transistor and one resistor (1T1R) architecture are successfully fabricated in this letter. The tested devices show low operation current (20 mu A), low switching voltage (set/reset, 0.8/-1 V), and reliable data retention for low-resistance state (LRS) with a 20-mu A set current at 80 degrees C (over ten years) via an excellent current limiter, namely, a metal-oxide-semiconductor field-effect transistor (MOSFET). In addition, multilevel storage characteristics are also demonstrated by modulating the amplitude of the MOSFET gate voltage. The various LRS levels obtained are possibly attributed to the formation of different numbers and sizes of conducting filaments consisting of oxygen vacancies caused by an external electric field. Moreover, reproducible resistive switching characteristics up to 2000 switching cycles are achieved in the same device. Our 1T1R ZrO(2)-based resistive switching access memory with low-power and highly reliable multilevel operation has high potential for practical applications.
Polyimide/Ta(2)O(5) nanocomposite gate insulators for enhanced organic thin-film transistor performance
(2011-08-01)
Chen, Liang-Hsiang
;
Lin, Pang
;
Ho, Jia-Chong
;
Lee, Cheng-Chung
;
Kim, Choongik
This study reports the preparation and characterization of polyimide/Ta(2)O(5) nanocomposite films as insulators for organic thin-film transistors (OTFTs). The degree of imidization, thermal, electrical, and surface properties of the nanocomposite films were characterized as a function of Ta(2)O(5) precursor contents. The nanocomposite films, with controlled/comparable insulator electrical characteristics and surface properties, have been found to enhance dielectric constant compared to pristine polyimide films, which resulted in improved pentacene TFT performance by a factor of 2-3 with carrier mobility values as high as 0.38 cm(2)/Vs. (C) 2011 Elsevier B.V. All rights reserved.
Highly reliable Si3N4-HfO2 stacked heterostructure to fully flexible poly-(3-hexylthiophene) thin-film transistor
(2011-08-01)
Meena, Jagan Singh
;
Chu, Min-Ching
;
Wu, Chung-Shu
;
Chang, Feng-Chih
;
Ko, Fu-Hsiang
A new and fully flexible Si3N4-HfO2 stacked poly-(3-hexylthiophene) p-type thin film transistor (P3HT-TFT) was successfully fabricated on thin semi-transparent polyimide (PI) substrate. The success of the TFT manufacturing adopts: (a) very simple and cost-effective sol-gel spin-coating technique to obtain 10-nm high-k HfO2 as dielectric layer over fully flexible PI substrate; (b) 50-nm silicon nitride (Si3N4) as the most efficient passivation layer on top of HfO2 film; (c) bendable 30-nm P3HT channel film by spin-coating method. Current-electric field characteristics of HfO2 layer in metal-insulator-metal (MIM) and TFT configurations, with or without Si3N4 passivation layer, were carefully evaluated. The origin of unsatisfactory leakage current in MIM and TFT structures could be effectively suppressed by means of Si3N4 film as the efficient passivation layer. The bottom-gate TFT demonstrated the on-to-off ratio 2 x 10(4) for drain current, -1.9 V threshold voltage and good saturation mobility (0.041 cm(2) V (1) s (1)). The proposed devices were examined in convex and concave types of various radii of curvature (R-C) in order to explore the manufacturing feasibility and electrical reliability of the fully flexible TFT for practical applications. In addition, various folding times and environmental stability on aforementioned devices with respective to electrical performances were also evaluated. (C) 2011 Elsevier B.V. All rights reserved.
Low-Power and Highly Reliable Multilevel Operation in ZrO2 1T1R RRAM
(2011-08-01)
Wu, Ming-Chi
;
Lin, Yi-Wei
;
Jang, Wen-Yueh
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
The Ti/ZrO2/Pt resistive memory devices with one transistor and one resistor (1T1R) architecture are successfully fabricated in this letter. The tested devices show low operation current (20 mu A), low switching voltage (set/reset, 0.8/-1 V), and reliable data retention for low-resistance state (LRS) with a 20-mu A set current at 80 degrees C (over ten years) via an excellent current limiter, namely, a metal-oxide-semiconductor field-effect transistor (MOSFET). In addition, multilevel storage characteristics are also demonstrated by modulating the amplitude of the MOSFET gate voltage. The various LRS levels obtained are possibly attributed to the formation of different numbers and sizes of conducting filaments consisting of oxygen vacancies caused by an external electric field. Moreover, reproducible resistive switching characteristics up to 2000 switching cycles are achieved in the same device. Our 1T1R ZrO2-based resistive switching access memory with low-power and highly reliable multilevel operation has high potential for practical applications.
Modeling the CO(2) emissions, energy use, and economic growth in Russia
(2011-08-01)
Pao, Hsiao-Tien
;
Yu, Hsiao-Cheng
;
Yang, Yeou-Herng
;
管理科學系
;
科技管理研究所
This paper applies the co-integration technique and causality test to examine the dynamic relationships between pollutant emissions, energy use, and real output during the period between 1990 and 2007 for Russia. The empirical results show that in the long-run equilibrium, emissions appear to be energy use elastic and output inelastic. This elasticity suggests high energy use responsiveness to changes in emissions. The output exhibits a negative significant impact on emissions and does not support EKC hypothesis. These indicate that both economic growth and energy conservation policies can reduce emissions and no negative impact on economic development The causality results indicate that there is a bidirectional strong Granger-causality running between output, energy use and emissions, and whenever a shock occurs in the system, each variable makes a short-run adjustment to restore the long-run equilibrium. The average speed of adjustment is as low as just over 0.26 years. Hence, in order to reduce emissions, the best environmental policy is to increase infrastructure investment to improve energy efficiency, and to step up energy conservation policies to reduce any unnecessary waste of energy. That is, energy conservation is expected to improve energy efficiency, thereby promoting economic growth. (C) 2011 Elsevier Ltd. All rights reserved.
Digital time-modulation pixel memory circuit in LTPS technology
(2011-08-01)
Chen, Szu-Han
;
Ker, Ming-Dou
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Wang, Tzu-Ming
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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
A digital time-modulation pixel memory circuit on glass substrate has been designed and verified for a 3-mu m low-temperature polysilicon (LTPS) technology. From the experimental results, the proposed circuit can generate 4-bit digital codes and the corresponding inversion data with a time-modulation technique. While the liquid-crystal-display (LCD) panel operates in the still mode, which means the same image is displayed on the panel, a data driver for an LCD panel is not required to provide the image data of the frame by the proposed pixel memory circuit. This pixel memory circuit can store the frame data and generate its corresponding inversion data to refresh a static image without activating the data driver circuit. Therefore, the power consumption of a data driver can be reduced in the LCD panel.
Characterization and identification of essential residues of the glycoside hydrolase family 64 laminaripentaose-producing--1, 3-glucanase
(2011-08-01)
Shrestha, Keshab Lal
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Liu, Sheng-Wen
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Huang, Chin-Ping
;
Wu, Hsin-Mao
;
Wang, Wen-Ching
Laminaripentaose-producing -1,3-glucanase (LPHase) from Streptomyces matensis DIC-108 uniquely catalyzes the hydrolysis of -1,3-glucan to release laminaripentaose as the predominant product. For studying this novel enzyme, the gene of LPHase was reconstructed with polymerase chain reaction and over-expressed in Escherichia coli. The recombinant wild-type enzyme and various mutants were further purified to 90 homogeneity on an ion-exchange chromatograph. The catalysis of the recombinant LPHase is confirmed to follow a one-step single-displacement mechanism with (1)H-NMR spectrometry. To determine the amino-acid residues essential for the catalysis, more than ten residues, including five highly conserved residuesAsp(143), Glu(154), Asp(170), Asp(376) and Asp(377), were mutated. Among the mutants, E154Q, E154G, D174N and D174G significantly lost catalytic activity. Further investigation with chemical rescue using sodium azide on E154G and D174G confirmed that Glu(154) functions as the general acid whereas Asp(170) serves as the general base in a catalytic turnover. This work is the first report that provides direct information for the identification of the essential residues of GH-64 through kinetic examination.
Efficiency enhancement of the poly-silicon solar cell using self-assembled dielectric nanoparticles
(2011-08-01)
Huang, C. K.
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Lin, H. H.
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Chen, J. Y.
;
Sun, K. W.
;
Chang, W. -L.
In this study, silica nanospheres dispersed in a surfactant solution were spin-coated on commercially available silicon solar cells to form colloidal crystals on the surface. This self-assembled nanoparticle layer served as an anti-reflection (AR) layer for solar cell devices. The self-assembled layer exhibits excellent anti-reflection properties in the UV and NIR wavelength regions, and the reflectance spectra match the theoretical prediction done using the rigorous coupled-wave analysis model. We also showed that the overall conversion efficiency of polycrystalline Si solar cells coated with the silica nanospheres was increased from 11% to 12.3% when using optimized spin-coating parameters and nanoparticle concentrations. (C) 2011 Elsevier B.V. All rights reserved.
A Single-Walled Carbon Nanotube Network Gas Sensing Device
(2011-08-01)
Wang, Li-Chun
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Tang, Kea-Tiong
;
Teng, I-Ju
;
Kuo, Cheng-Tzu
;
Ho, Cheng-Long
The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT) networks. The SWCNT networks are synthesized on Al(2)O(3)-deposted SiO(2)/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD). The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO(2) and NH(3) vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO(2) and 24 ppm for NH(3).
ON ORDERS OF M(2, K) OVER A NON-ARCHIMEDEAN LOCAL FIELD
(2011-08-01)
Tu, Fang-Ting
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應用數學系
;
Department of Applied Mathematics
Let K be a non-Archimedean local field. In this paper, we first show that if an order in M(2, K) is the intersection of (finitely many) maximal orders in M(2, K), then it is the intersection of at most three maximal orders. Using this result, we obtain a complete classification of orders in M(2, K) that are intersections of maximal orders.
Detecting small lung tumors in mouse models by refractive-index microradiology
(2011-08-01)
Chien, Chia-Chi
;
Zhang, Guilin
;
Hwu, Y.
;
Liu, Ping
;
Yue, Weisheng
Refractive-index (phase-contrast) radiology was able to detect lung tumors less than 1 mm in live mice. Significant micromorphology differences were observed in the microradiographs between normal, inflamed, and lung cancer tissues. This was made possible by the high phase contrast and by the fast image taking that reduces the motion blur. The detection of cancer and inflammation areas by phase contrast microradiology and microtomography was validated by bioluminescence and histopathological analysis. The smallest tumor detected is less than 1 mm(3) with accuracy better than 1 x 10(-3) mm(3). This level of performance is currently suitable for animal studies, while further developments are required for clinical application.
Nanoscale Control of Phase Variants in Strain-Engineered BiFeO3
(2011-08-01)
Vasudevan, Rama K.
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Liu, Yunya
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Li, Jiangyu
;
Liang, Wen-I
;
Kumar, Amit
Development of magnetoelectric, electromechanical, and photovoltaic devices based on mixed-phase rhombohedral-tetragonal (R-T) BiFeO3 (BFO) systems is possible only if the control of the engineered R phase variants is realized. Accordingly, we explore the mechanism of a bias induced phase transformation in this system. Single point spectroscopy demonstrates that the T -> R transition is activated at lower voltages compared to T -> - T polarization switching. With phase field modeling, the transition is shown to be electrically driven. We further demonstrate that symmetry of formed R-phase rosettes can be broken by a proximal probe motion, allowing controlled creation of R variants with defined orientation. This approach opens a pathway to designing next-generation magnetoelectronic and data storage devices in the nanoscale.
靜電放電保護裝置
(2011-08-01)
柯明道
;
許哲綸
;
周業甯
;
林耿立
;
黃曄仁
一種靜電放電保護裝置，包括一第一放電單元、一第二放電單元、一第一觸發單元以及一第二觸發單元。第一及第二放電單元串聯於一第一接觸墊與一第二接觸墊之間，用以釋放一靜電放電電流。當一靜電放電事件發生時，第一觸發單元觸發第一放電單元。當第一放電單元被觸發時，第二觸發單元觸發第二放電單元。
Fuzzy Modeling and Synchronization of Two Totally Different Chaotic Systems via Novel Fuzzy Model
(2011-08-01)
Li, Shih-Yu
;
Ge, Zheng-Ming
;
機械工程學系
;
Department of Mechanical Engineering
In this paper, a new fuzzy model is presented to simulate and synchronize two totally different and complicated chaotic systems, namely, 1) quantum cellular neural networks nanosystem (Quantum-CNN system) and 2) Qi system. Through the new fuzzy model, the following three main advantages can be obtained: 1) only two linear subsystems are needed; 2) the numbers of fuzzy rules can be reduced from 2(N) to 2 x N (comparing with the Takagi-Sugeno fuzzy model), where N is the number of nonlinear terms; 3) fuzzy synchronization of two different chaotic systems with different numbers of nonlinear terms can be achieved with only two sets of gain K. There are two examples in numerical simulation results to show the effectiveness and feasibility of our new model.
k center dot p Zincblende Hamiltonian and Optical Matrix with Bulk Inversion Asymmetry
(2011-08-01)
Chen, Chun-Nan
;
Su, Wei-Long
;
Lee, Meng-En
;
Jen, Jen-Yi
;
Li, Yiming
A conventional 8 x 8 k.p zincblende Hamiltonian is corrected to include the bulk (or intracell) inversion asymmetry. Meanwhile, a conventional 8 x 8 k.p zincblende optical matrix is also corrected to include this intracell asymmetry. (C) 2011 The Japan Society of Applied Physics
A Novel Tunable Green- to Yellow-Emitting beta-YFS:Ce3+ Phosphor for Solid-State Lighting
(2011-08-01)
Wu, Yun-Chen
;
Wang, De-Yin
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Chen, Teng-Ming
;
Lee, Chi-Shen
;
Chen, Kuo-Ju
A Ce3+-activated fluorosulfide phosphor (beta-YFS: Ce3+) was synthesized by solid-state reaction in a sealed tube. The crystal structure has been refined from the XRD profiles and there are two different crystallographic rare earth sites, namely, Y(1) and Y(2), where the Ce3+ ions occupied. The emission band with a maximum at 495 nm of beta-Y0.99Ce0.01 FS phosphor was characterized by the 4f-5d transitions of Ce3+ ion. With increasing Ce3+ concentration, the emission variations were observed from 495 to 547 nm. When beta-YFS:Ce3+ phosphors were utilized to incorporate with n-UV/blue chip, greenish-white light with color rendering index of 65-77 were obtained. The results indicate that the tunable green- to yellow-emitting beta-YFS:Ce3+ can serve as a potential phosphor for incorporation in fabrication for solid-state lighting. The preparation, spectroscopic characterization, quantum efficiency, thermal-quenching behavior, and related LED device data are also presented.