Browsing by Issue Date, starting with "2009-06-23"

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Thermodynamic Characterization of Polymorphs in Bulk-Crystallized Syndiotactic Polystyrene via Small/Wide-Angle X-ray Scattering and Differential Scanning Calorimetry
(2009-06-23)
Su, C. H.
;
Jeng, U.
;
Chen, S. H.
;
Cheng, C. -Y.
;
Lee, J. -J.
By means of in situ small/wide-angle X-ray scattering (SAXS/WAXS) and differential scanning calorimetry (DSC), we examined evolutions of lamellar crystal thickness for alpha and beta crystals, respectively, in bulk-crystallized syndiotactic polystyrene (sPS) during the partial melting-reorganization process upon progressive heating up to 290 degrees C. For the SAXS data analysis, the Kratky-Porod approximation proves to be particularly helpful in extracting the crystal thickness when approaching final melting where crystalline lamellae (near equilibration with the melt) exist in low concentrations as dispersed entities instead of in arrays. On the basis of the crystal thicknesses at elevated temperatures under solid-melt equilibration, we constructed melting lines of the two separate forms in the Gibbs-Thomson phase plane. The extrapolated (to infinite lamellar thickness) equilibrium melting temperature T(m,alpha)* approximate to 294 degrees C of the a form is moderately lower than T(m,beta)* approximate to 306 degrees C of the beta form. The two melting lines intercept at a crossover temperature T(Q) approximate to 284 degrees C and crystal thickness l(Q) approximate to 9.6 nm, where the relative thermal stability of the two phases inverses. For crystals thicker than l(Q) (practically hard to reach for bulk crystallization under ambient pressure), the beta form is the stable phase; for crystals thinner than I(Q) (the commonly accessible case), the a form is circumstantially more stable. With crystallinity-corrected values of the heat of fusion Delta H(f,alpha) approximate to 82 MJ m(-3) and Delta H(f,beta) approximate to 146 MJ m(-3) obtained from a combination of DSC and WAXS results, we determined from the slope (= 2 sigma(e)/Delta H(f)) of the melting line that basal surface energy sigma(e,alpha) approximate to 8.2 mJ m(-2) and sigma(e,beta) approximate to 26.8 mJ m(-2) which are considerably lower than those expected for tight folds, indicative of nonadjacently re-entered or loosely looped folds. The combination of lower T(m)*, Delta H(f), Delta S(f), and sigma(e) values renders the a phase highly competitive in the rate of nucleation at low temperatures but much less so at high temperatures as compared to the beta phase. The higher sigma(e,beta) value is also consistent with the observation that the beta phase is more responsive to externally added heterogeneous nucleation agents.
A 2 Ma record of explosive volcanism in southwestern Luzon: Implications for the timing of subducted slab steepening
(2009-06-25)
Ku, Yueh-Ping
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Chen, Chang-Hwa
;
Song, Sheng-Rong
;
Iizuka, Yoshiyuki
;
Shen, Jason Jiun-San
New chemical and isotopic analyses of the tephra layers plus deep-sea tephrostratigraphic record from two cores from either side of Luzon Island (Philippines) have allowed the identification of two periods of explosive volcanic activity originating from the Macolod Corridor in the southwestern part of the Luzon. The first period extended from prior to 1355 ka to 1977 ka, and the second period extended from 478 ka to the present, separated by a period of relative quiescence. The time intervals between large explosive eruption events in each period were 31 +/- 15 ka and 156 +/- 52 ka, respectively. Combined with published chronological and geochemical data from onshore volcanic deposits, the tephrostratigraphic record shows that the locus of large explosive eruptions has migrated southwestward from the northeastern section to the middle and southwestern sections of the Macolod Corridor. The period of relative quiescence is characterized by monogenetic volcanism in the central section of the corridor. The migration of active volcanism across the southwestern part of Luzon during the Quaternary is used to infer the evolution of the subducting South China Sea crust. The period of relative quiescence represents a period of adjustment of the subducted slab by steepening, which began around 1355 ka or shortly thereafter and finished at around 478 ka.
APPARATUS OF MULTI-STAGE NETWORK FOR ITERATIVE DECODING AND METHOD THEREOF
(2009-06-25)
WONG, Cheng-Chi
;
LEE, Yung-Yu
;
LAI, Ming-Wei
;
LIN, Chien-Ching
;
CHANG, Hsie-Chia
An apparatus and method of multi-stage network for iterative network are disclosed. The apparatus has M stages, and each stage uses N multiplexers to transmit N codeword partitions simultaneously. Every starting terminal, either the output port of memories, soft-in soft-out decoders, or multiplexers, has two paths to couple with two different multiplexers at next stage. One path connects the source to the first data port of one multiplexer; the other connects the source to the second data port of another multiplexer. The two multiplexers will be controlled with the same 1-bit signal, so each source has only one valid path to next stage. The invention can guarantee that the transmission of N data blocks is free from contention.
Leakage current cut-off device for ternary content addressable memory
(2009-06-25)
Huang, Po-Tsang
;
Liu, Wen-Yen
;
Hwang, Wei
A leakage current cut-off device for a ternary content addressable memory is provided. The storage cell of a ternary content addressable memory may be in the active mode, data-retention mode and cut-off mode. This invention applies a multi-mode data retention power gating device to the storage cell of the ternary content addressable memory to reduce the leakage current through the storage cell in the data-retention mode and the cut-off mode, and support the full speed operation in the active mode.
MULTI-PERSON POSE RECOGNITION SYSTEM USING A ZIGBEE WIRELESS SENSOR NETWORK
(2009-06-25)
Chen, Chun-Wei
;
Song, Kai-Tai
In the present invention, a multi-person pose recognition system has been developed. This system includes a body pose detection module, a CC2420DBK board and a multi-person pose monitoring software module. The body pose detection module includes a triaxial accelerometer, a Zigbee chip and an 8-bit microcontroller. Several body pose detection modules and the CC2420DBK board form a Zigbee wireless sensor network (WSN). The CC2420DBK board functions as the receiver of the Zigbee WSN and communicates with a robot onboard computer or a host computer through a RS-232 port. The multi-person pose monitoring software monitors and records activities of multiple users simultaneously. The present invention provides a pose recognition algorithm by combining time-domain analysis and wavelet transform analysis. This algorithm has been implemented in the microcontroller of a body pose estimation module. Through the algorithm, the system can recognize seven body poses: falling, standing, sitting, lying, walking, going upstairs and going downstairs.
PHOSPHORS AND LIGHTING APPARATUS USING THE SAME
(2009-06-25)
CHEN, Teng-Ming
;
Chen, Po-Ju
A phosphor has a chemical formula of: (X1-mEum)4Y(BO3)3, wherein X is at least one of the group consisting of Ca, Sr and Ba, and Y is at least one of the group consisting of Li, Na and K, while 0
RUN-TIME RECONFIGURABLE FABRIC FOR 3D TEXTURE FILTERING SYSTEM
(2009-06-25)
WANG, Wei-Ting
;
YANG, Hui-Chin
;
HSU, R-Ming
;
CHUNG, Chung-Ping
The present invention discloses a texture filtering system, comprising a sequence generator, a retrieve unit and a dispatch unit. The sequence generator generates an execution sequence in each duty cycle. The execution sequence is the priority of respectively retrieving multiple pixels from multiple queues. The retrieve unit outputs multiple Boolean signals based on the limitation of the total number of all-purpose texture filters and the above priority in a duty cycle for determining from which queues the pixels are retrieved to perform a texture filtering process, and the dispatch unit assigns the multiple texture filter formats of the pixels to be processed and the anisotropic ratios thereof to multiple address generators. Besides, the present invention utilizes Brute force method to enable multiple bilinear texture filters to satisfy the various texture filter formats of a pixel, thereby markedly reducing the space occupied by the texture filter in a 3D graphic processing unit, provided that the specifications of the address generators and texture cache memory are unchanged.
Super leakage current cut-off device for ternary content addressable memory
(2009-06-25)
Huang, Po-Tsang
;
Liu, Wen-Yen
;
Hwang, Wei
A super leakage current cut-off device for a ternary content addressable memory (TCAM) is provided. For various operations of the TCAM, the device uses the high-end and low-end power gating control transistors to turn on/off the don't-care cells to reduce the leakage current passing through the don't-care cells.
Robust visual tracking control system of a mobile robot based on a dual-Jacobian visual interaction model
(2009-06-30)
Tsai, Chi-Yi
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Song, Kai-Tai
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Dutoit, Xavier
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Van Brussel, Hendrik
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Nuttin, Marnix
This paper presents a novel design of a robust visual tracking control system, which consists of a visual tracking controller and a visual state estimator. This system facilitates human-robot interaction of a unicycle-modeled mobile robot equipped with a tilt camera. Based on a novel dual-Jacobian visual interaction model, a robust visual tracking controller is proposed to track a dynamic moving target. The proposed controller not only possesses some degree of robustness against the system model uncertainties, but also tracks the target without its 3D velocity information. The visual state estimator aims to estimate the optimal system state and target image velocity, which is used by the visual tracking controller. To achieve this, a self-tuning Kalman filter is proposed to estimate interesting parameters and to overcome the temporary occlusion problem. Furthermore, because the proposed method is fully working in the image space, the computational complexity and the sensor/camera modeling errors can be reduced. Experimental results validate the effectiveness of the proposed method, in terms of tracking performance, system convergence, and robustness. (C) 2009 Elsevier B.V. All rights reserved.
Size-Dependent Strain Relaxation and Optical Characteristics of InGaN/GaN Nanorod LEDs
(2009-07-01)
Wu, Yuh-Renn
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Chiu, Chinghua
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Chang, Cheng-Yu
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Yu, Peichen
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Kuo, Hao-Chung
In this paper, InGaN/GaN nanorod LEDs with various sizes are fabricated using self-assembled Ni nanomasks and inductively coupled plasma-reactive ion etching. Photoluminescence (PL) characteristics exhibit size-dependent, wavelength blue shifts of the emission spectra from the nanorod LEDs. Numerical analyses using a valence force field model and a self-consistent Poisson, Schrodinger, and drift-diffusion solver quantitatively describe the correlation between the wavelength blue shifts and the strain relaxation of multiple quantum wells embedded in nanorods with different averaged sizes. Time-resolved PL studies confirm that the array with a smaller size exhibits a shorter carrier lifetime at low temperature, giving rise to a stronger PL intensity. However, the PL intensity deteriorates at room temperature, compared to that of a larger size, possibly due to an increased number of surface states, which decreases the nonradiative lifetime, and hence reduces the internal quantum efficiency.
Wideband LNA Compatible for Differential and Single-Ended Inputs
(2009-07-01)
Kuo, Ming-Ching
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Kuo, Chien-Nan
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Chueh, Tzu-Chan
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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
This letter presents a wideband low-noise amplifier (LNA) that supports both differential and single-ended inputs, while providing differential output. The LNA is implemented in 0.13 mu m. CMOS technology. For sub-1 GHz wideband applications, this LNA achieves 22.5 dB voltage gain, +1 dBrn IIP3, and 2.5 dB NF in the differential receiving mode, while achieving 23 dB voltage gain, -0.5 dB m IIP3, and 2.65 dB NF in the single-ended receiving mode. The LNA core circuit draws 2.5 mA from 1.2 V supply voltage, and occupies a small chip area of 0.06 mm(2).
Astigmatic diffractive optical element for swing-arm-type optical pickup head
(2009-07-01)
Lee, Chi-Hung
;
Chiu, Yi
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Shieh, Han-Ping D.
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電控工程研究所
;
光電工程學系
Based on a finite-conjugate objective lens with numerical aperture of 0.62 for a 650-nm wavelength, an optical pickup head composed of a multifunction beamsplitter and a diffractive optical element is designed be used in a swing-arm-type optical pickup head. The diffractive optical element is a lens with an elliptical four-level phase profile to provide both focusing and astigmatism. It is also designed with the goal to simplify the overall optical configuration and provide linear characteristics for the focus error signal. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI:10.1117/1.3158944]
Computational identification of riboswitches based on RNA conserved functional sequences and conformations
(2009-07-01)
Chang, Tzu-Hao
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Huang, Hsien-Da
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Wu, Li-Ching
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Yeh, Chi-Ta
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Liu, Baw-Jhiune
Riboswitches are cis-acting genetic regulatory elements within a specific mRNA that can regulate both transcription and translation by interacting with their corresponding metabolites. Recently, an increasing number of riboswitches have been identified in different species and investigated for their roles in regulatory functions. Both the sequence contexts and structural conformations are important characteristics of riboswitches. None of the previously developed tools, such as covariance models (CMs), Riboswitch finder, and RibEx, provide a web server for efficiently searching homologous instances of known riboswitches or considers two crucial characteristics of each riboswitch, such as the structural conformations and sequence contexts of functional regions. Therefore, we developed a systematic method for identifying 12 kinds of riboswitches. The method is implemented and provided as a web server, RiboSW, to efficiently and conveniently identify riboswitches within messenger RNA sequences. The predictive accuracy of the proposed method is comparable with other previous tools. The efficiency of the proposed method for identifying riboswitches was improved in order to achieve a reasonable computational time required for the prediction, which makes it possible to have an accurate and convenient web server for biologists to obtain the results of their analysis of a given mRNA sequence. RiboSW is now available on the web at http://RiboSW.mbc.nctu.edu.tw/.
Possibility of direct exchange diffusion of hydrogen on the Cl/Si(100)-2X1 surface
(2009-07-01)
Hsieh, Ming-Feng
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Lin, Deng-Sung
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Tsay, Shiow-Fon
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物理研究所
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Institute of Physics
The diffusion behavior of hydrogen substitutional sites on the chlorine-terminated Si(100) surface was investigated at elevated temperatures using time-lapse scanning tunneling microscopy (STM). STM movies show that each hydrogen atom undergoes Brownian motion within a monochloride dimer row. The position of a hydrogen substitutional site is exchanged directly with that of an immediate neighboring chlorine atom in either the same dimer (intradimer diffusion) or in one of the two adjacent dimers in the same row (intrarow diffusion). Accordingly, conceptual direct exchange diffusion (DED) in a two-dimensional lattice was experimentally observed. Analysis of STM movies at various temperatures yielded rather low attempt frequencies and energy barriers, leading to the suggestion that the diffusion mechanism involves an intermediate low-energy molecular state. Density-functional theory (DFT) calculations were also performed and provided partial support for the proposed diffusion mechanism.
A target-specific approach for the identification of tyrosine-sulfated hemostatic proteins
(2009-07-01)
Liu, Tzu-An
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Yasuda, Shin
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Williams, Frederick E.
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Liu, Ming-Yih
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Suiko, Masahito
A simple methodology for the identification of hemostatic proteins that are subjected to post translational tyrosine sulfation was developed. The procedure involves sequence analysis of members of the three hemostatic pathways using the Sulfinator prediction algorithm, followed by [(35)S]sulfate labeling of cultured HepG2 human hepatoma cells, immunoprecipitation of targeted [(35)S]sulfate-labeled hemostatic proteins, and tyrosine O-[(35)S]sulfate analysis of immunoprecipitated proteins. Three new tyrosine-sulfated hemostatic proteins-protein S. prekallikrein, and plasminogen-were identified. Such a target-specific approach will allow investigation of tyrosine-sulfated proteins of other biochemical/physiological pathways/processes and contribute to a better understanding of the functional role of post-translational tyrosine sulfation. (C) 2009 Elsevier Inc. All rights reserved.
Optimization on MOS-Triggered SCR Structures for On-Chip ESD Protection
(2009-07-01)
Chen, Shih-Hung
;
Ker, Ming-Dou
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電機學院
;
College of Electrical and Computer Engineering
MOS-triggered silicon-controlled rectifier (SCR) devices have been reported to achieve efficient on-chip electrostatic discharge (ESD) protection in deep-submicrometer CMOS technology. The channel length of the embedded MOS transistor in the MOS-triggered SCR device dominates the trigger mechanism and current distribution to govern the trigger voltage, holding voltage, on resistance, second breakdown current, and ESD robustness of the MOS-triggered SCR device. The embedded MOS transistor in the MOS-triggered SCR device should be optimized to achieve the most efficient ESD protection in advanced CMOS technology. In addition, the layout style of the embedded MOS transistor can be adjusted to improve the MOS-triggered SCR device for ESD protection.
An Effective Scheduling Approach for Maximizing Polyimide Printing Weighted Throughput in Cell Assembly Factories
(2009-07-01)
Chung, S. H.
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Tai, Y. T.
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Pearn, W. L.
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工業工程與管理學系
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Department of Industrial Engineering and Management
Polyimide printing (PI) is an important process operation but also often the cause of bottlenecks in capital-intensive cell assembly factories. Therefore, the development of an effective scheduling method to maximize throughput in this PI process is essential and difficult. In the polyimide printing scheduling problem (PISP), jobs are given weights and clustered by their product types, which must be processed on identical parallel PI machines. The setup times for two consecutive jobs between different product types in the PI machines are sequence-dependent. In this paper, the PISP is formulated as a mixed integer linear programming model. The PISP is also transformed into a multiple tour maximum collection problem (MTMCP), a well-known network problem which has been investigated extensively. Based on this transformation, one can therefore solve the PISP near-optimally using the efficient algorithm.
三元內容可定址記憶體漏電流截斷裝置
(2009-07-01)
黃柏蒼
;
劉文彥
;
黃威
一種應用於三元內容可定址記憶體漏電流截斷裝置。三元內容可定址記憶體之儲存記憶胞區分為運轉模式、待機模式及截止模式,本發明利用多模式閘極電源控制裝置降低三元電晶體可定址記憶體之儲存記憶胞在待機模式及截止模式之漏電流並維持運轉模式執行效能。
A Comparative Study of Carrier Transport for Overlapped and Nonoverlapped Multiple-Gate SOI MOSFETs
(2009-07-01)
Lee, Wei
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Su, Pin
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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
This paper provides a comparative study of carrier transport characteristics for multiple-gate silicon-on-insulator MOSFETs with and without the nonoverlapped source/drain structure. For the overlapped devices, we observed Boltzmann law in subthreshold characteristics and phonon-limited behavior in the inversion regime. For the nonoverlapped devices, however, we found insensitive temperature dependence for drain current in both subthreshold and inversion regimes. Our low-temperature measurements indicate that the intersubband scattering is the dominant carrier transport mechanism for narrow overlapped multigate field-effect transistors (MuGFETs). For the nonoverlapped MuGFETs, the voltage-controlled potential barriers in the nonoverlapped regions may give rise to the weak localization effect (conductance reduction) and the quantum interference fluctuations.
Low-Complexity ICI Mitigation Methods for High-Mobility SISO/MIMO-OFDM Systems
(2009-07-01)
Hsu, Chao-Yuan
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Wu, Wen-Rong
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電信工程研究所
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Institute of Communications Engineering
In orthogonal frequency-division multiplexing (OFDM) systems, it is generally assumed that the channel response is static in an OFDM symbol period. However, the assumption does not hold in high-mobility environments. As a result, intercarrier interference (ICI) is induced, and system performance is degraded. A simple remedy for this problem is the application of the zero-forcing (ZF) equalizer. Unfortunately, the direct ZF method requires the inversion of an N x N ICI matrix, where N is the number of subcarriers. When N is large, the computational complexity can become prohibitively high. In this paper, we first propose a low-complexity ZF method to solve the problem in single-input-single-output (SISO) OFDM systems. The main idea is to explore the special structure inherent in the ICI matrix and apply Newton's iteration for matrix inversion. With our formulation, fast Fourier transforms (FFTs) can be used in the iterative process, reducing the complexity from O(N(3)) to O( N log(2) N). Another feature of the proposed algorithm is that it can converge very fast, typically in one or two iterations. We also analyze the convergence behavior of the proposed method and derive the theoretical output signal-to-interference-plus-noise ratio (SINR). For a multiple-input-multiple-output (MIMO) OFDM system, the complexity of the ZF method becomes more intractable. We then extend the method proposed for SISO-OFDM systems to MIMO-OFDM systems. It can be shown that the computational complexity can be reduced even more significantly. Simulations show that the proposed methods perform almost as well as the direct ZF method, while the required computational complexity is reduced dramatically.