Browsing by Issue Date, starting with "2006-06-05"

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Strain relaxation and induced defects in InAsSb self-assembled quantum dots
(2006-06-05)
Chen, J. F.
;
Hsiao, R. S.
;
Huang, W. D.
;
Wu, Y. H.
;
Chang, L.
The onset of strain relaxation and induced defects in InAs0.94Sb0.06 quantum dots are investigated. We show that the relaxation causes partial carrier depletion in the dots and drastic carrier depletion in the top GaAs layer due to the introduction of two defect traps At 0.35 and 0.64 eV. This result is consistent with transmission electron microscopy data which show misfit dislocations on the edges of the dot upper boundary and threading dislocations in the top GaAs layer. The bottom GaAs layer is dislocation-free, and thus the strain relaxation may initially occur on the edges of the dots. (c) 2006 American Institute of Physics.
Trap-state density in continuous-wave laser-crystallized single-grainlike silicon transistors
(2006-06-05)
Lin, Yu-Ting
;
Chen, Chih
;
Shieh, Jia-Min
;
Lee, Yao-Jen
;
Pan, Ci-Ling
This investigation characterizes electrical characteristics of continuous-wave green laser-annealed single-grainlike silicon thin-film transistors in relation to trap-state densities. As laser power increases, highly crystalline channels form, reducing tail-state densities to as low as 3 X 10(19) eV-' cm(-3). This occurrence is responsible for high field-effect electron mobility of 284 cm(2)/Vs. In contrast, increasing laser power initially reduces the deep-state density and then increases it to 3 X 1016 eV(-1) cm(-3). This reversal in deep-state density and thus in the subthreshold slope as well as a saturating reduction in threshold voltage are associated with the formation of extra interface defects caused by laser-crystallization-enhanced surface roughness. (c) 2006 American Institute of Physics.
Convalently bonded polyhedral oligomeric silsesquioxane/polyimide nanocomposites and process for synthesizing the same
(2006-06-08)
Wei, Kung-Hwa
;
Leu, Chyi-Ming
Polyhedral oligomeric silsesquioxane/polyimide nanocomposites with certain mechanical properties and low dielectric constant is synthesized by covalently tethering functionalized polyhedral oligomeric silsesquioxane molecules to polyimide. These nanocomposites appear to be self-assembled systems. A process for synthesizing said polyhedral oligomeric silsesquioxane/polyimide nanocomposites also is provided, comprising a step of forming porous type polyhedral oligomeric silsesquioxane, and a subsequent step of reacting with dianhydride or directly reacting with synthesized polyimide.
管管詩畫腦袋開花自然書詩集形式展現異想童趣風格
(2006-06-08)
劉郁青
Power gating structure having data retention and intermediate modes
(2006-06-08)
Hua, Chung-Hsien
;
Hwang, Wei
The present invention provides a power gating structure having data retention and intermediate modes and able to operate under multiple modes. A conventional power gating structure has only turn-on and turn-off functions, and is used to suppress a leakage current problem which has become more and more serious in advance manufacture processes, under a turn-off mode. However, in a memory circuit, such as latch, register and SRAM, when the power gate is turned off, a new power gating structure is required for data retention. The power gating structure of the present invention can be set into one of 4 different operational modes: a data retention mode for maintaining the static noise margin of the memory, an intermediate mode for reducing the interference on ground and power levels, an active mode used when the circuit operates in normal condition, and a standby mode used when the circuit does not operate.
Structure-stability-activity relationship in covalently cross-linked N-carbamoyl D-amino acid amidohydrolase and N-acylamino acid racemase
(2006-06-09)
Chiu, WC
;
You, JY
;
Liu, JS
;
Hsu, SK
;
Hsu, WH
N-Acylamino acid racemase (NAAAR) and N-carbamoyl-D-amino-acid amidohydrolase (D-NCAase) are important biocatalysts for producing enantiopure a-amino acids. NAAAR forms an octameric assembly and displays induced fit movements upon substrate binding, while D-NCAase is a tetramer that does not change conformation in the presence of a ligand. To investigate the effects of introducing potentially stabilizing S-S bridges in these different multimeric enzymes, cysteine residues predicted to form inter or intra-subunit disulfide bonds were introduced by site-directed mutagenesis. Inter-subunit S-S bonds were formed in two NAAAR variants (A68C-D72C and P60C-Y100C) and two D-NCAase variants (A302C and P295C-F304C). Intra-subunit S-S bonds were formed in two additional NAAAR variants (E149C-A182C and V265C). Crystal structures of NAAARs variants show limited deviations from the wild-type overall tertiary structure. An apo A68C-D72C subunit differs from the wild-type enzyme, in which it has an ordered lid loop, resembling ligand-bound NAAAR. The structures of A222C and A302C D-NCAases are nearly identical to the wild-type enzyme. All mutants with inter-subunit bridges had increases in thermostability. Compared with the wild-type enzyme, A68C-D72C NAAAR showed similar k(cat)/K-m ratios, whereas mutant D-NCAases demonstrated increased k(cat)/K-m ratios at high temperatures (A302C: 4.2-fold at 65 degrees C). Furthermore, molecular dynamic simulations reveal that A302C substantially sustains the fine-tuned catalytic site as temperature increases, achieving enhanced activity. (c) 2006 Elsevier Ltd. All rights reserved.
Strategy of packet detection for burst-mode OFDM systems
(2006-06-10)
Peng, Chia-Sheng
;
Chuang, Yuan-Shin
;
Wen, Kuei-Ann
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
An efficient method on selecting threshold values according to minimax test for packet detection in burst-mode OFDM systems is proposed. Packet detection decides whether a packet is coming or not by comparing a threshold value in the wireless receiver. Related with sliding window size and SNR, the threshold value affects receiving performance including probabilities of false alarm and miss. The minimax test for detection based on empirical CDF and survival functions is proposed. Also the performances of two general used detection methods are surveyed and compared.
Multiple-process performance analysis chart based on process loss indices
(2006-06-10)
Pearn, W. L.
;
Chang, Y. C.
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Wu, Chien-Wei
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Control chart techniques have been widely used in the manufacturing industry for controlling and monitoring process performance and are practical tools for quality improvement. When dealing with variable data, one usually employs the (X) over bar chart and R chart ( or S chart) to detect the process mean and process variance change. These charts are easy to understand and effectively communicate critical process information without using words and formulae. In this paper, we develop a new multiple-process performance analysis chart (MPPAC), using the process loss index L-e to control the product quality and/or reliability for multiple manufacturing processes. Upper confidence bounds are applied to the L-e MPPAC to ensure the capability groupings are accurate, which is essential to product quality assurance. The L-e MPPAC displays the multiple-process relative inconsistency and process relative off-target degree on one single chart in order to provide simultaneous capability control for multiple processes. We demonstrate the applicability of the proposed L-e MPPAC incorporating the upper confidence bounds by presenting a case study on some liquid-crystal display module manufacturing processes, to evaluate the factory performance.
The formation of perovskite PbTiO3 powders by sol-gel process
(2006-06-10)
Lee, CY
;
Tai, NH
;
Sheu, HS
;
Chiu, HT
;
Hsieh, SH
Nano-sized cubic Pb2Ti2O6 and monoclinic PbTi3O7 were obtained as the first stage products, by sol-gel process using anhydrous lead acetate and titanium(IV) isopropoxide as precursors; then, as the powder was heated, Pb2Ti2O6 gradually transformed to perovskite PbTiO3 around 673 K. (c) 2005 Elsevier B.V. All rights reserved.
Analytical solutions of the azimuthal deviation of a polarizer and an analyzer by polarizer-sample-analyzer ellipsometry
(2006-06-10)
Chao, YF
;
Lee, KY
;
Lin, YD
;
光電工程學系
;
Department of Photonics
The analytical solutions of the azimuthal deviation of a polarizer and an analyzer were obtained by polarizer-sample-analyzer ellipsometry with a three-intensity measurement technique. By performing two sets of this three-intensity measurement with the polarizer's azimuth set at 45 degrees and at -45 degrees, we were able to obtain a set of ellipsometric parameters free from the azimuthal deviations of the polarizer and the analyzer. (c) 2006 Optical Society of America.
Erbium doped GaSe crystal for mid-IR applications
(2006-06-12)
Hsu, YK
;
Chen, CW
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Huang, JY
;
Pan, CL
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光電工程學系
We reported a type-I difference-frequency generator (DFG), based on erbium doped GaSe (Er: GaSe) crystals as a coherent infrared source tunable from 2.4 mu m to 28 mu m. The two mixing beams used for the DFG are a tunable near infrared output (1.1-1.8 mu m) from an optical parametric amplifier (OPA) and the fundamental beam of a picosecond Nd: YAG laser at 1.064 mu m. The system can produce a maximum output pulse energy of 5 mu J at wavelength of 3.5 mu m, corresponding to a photon conversion efficiency of 8% at a pump intensity of 1.7 GW/cm(2). The nonlinear coefficient (d(eff)) of 0.5 atom % erbium doped GaSe crystal was found to be 55.3 pm/V or 24 % higher than that of a pure GaSe crystal. The improvement of deff is attributed to the substitutive and interstitial doping of Er ion in GaSe unit cell. The optical properties of GaSe influenced by the erbium doping are also presented. (c) 2006 Optical Society of America.
Optically heterodyne diagnosis of a high-saturation-power undoped InP sandwiched InGaAs p-i-n photodiode grown on GaAs
(2006-06-12)
Liao, YS
;
Shi, JW
;
Wu, YS
;
Kuo, HC
;
Feng, M
We demonstrate the optical heterodyne diagnostics and high saturation power characteristics of a novel undoped InP sandwiched In0.53Ga0.47As p-i-n photodiode with a partially p-doped photoabsorption layer, which is grown on a linearly graded metamorphic InxGa1-xP buffered GaAs substrate layer and exhibits an excellent low dark current density of 3.6 x 10(-7) A/cm(2). Such a top-illuminated optical receiver exhibits an illuminating window of 60-mu m diameter, which performs ultra-linear power handling capability up to 18 dBm at 1550 nm, providing a maximum photocurrent of 35 mA under a reverse bias of 9 volts. These result in extremely high current bandwidth and bandwidth-responsivity products of 350 mA center dot GHz and 4.8 GHz center dot A/W, respectively, at receiving frequency of up to 10 GHz. (c) 2006 Optical Society of America.
Energy-tunable transmission x-ray microscope for differential contrast imaging with near 60 nm resolution tomography
(2006-06-12)
Yin, GC
;
Tang, MT
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Song, YF
;
Chen, FR
;
Liang, KS
An energy-tunable transmission hard x-ray microscope with close to 60 nm spatial resolution in three dimensions (3D) has been developed. With a cone beam illumination, a zone plate of 50 nm outmost zone width, a stable mechanical design, and software feedback, we obtained tomographic data sets that are close to 60 nm spatial resolution. Meanwhile, the element specific imaging was also obtained by a differential absorption contrast technique used below and above the absorption of the element. Examples of advanced intergraded circuit devices are used to demonstrate the element selectivity and spatial resolution in 3D of the microscope.
Single-longitudinal-mode, tunable dual-wavelength, CWNd : YVO4 laser
(2006-06-12)
Lin, YY
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Chen, SY
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Chiang, AC
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Tu, RY
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Huang, YC
We report a single-longitudinal-mode CW diode-pumped Nd:YVO4 laser emitting at both 1064 and 1342 nm with 10% optical efficiency at 20-W pump power. The measured spectral widths at 1064 and 1342 nm were less than 450 MHz and 400 MHz, respectively. The two emission wavelengths can be independently tuned over the lasing bandwidths of the dual-wavelength laser. (c) 2006 Optical Society of America.
Analysis of circular genome rearrangement by fusions, fissions and block-interchanges
(2006-06-12)
Lu, Chin Lung
;
Huang, Yen Lin
;
Wang, Tsui Ching
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Chiu, Hsien-Tai
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生物科技學系
Background: Analysis of genomes evolving via block-interchange events leads to a combinatorial problem of sorting by block-interchanges, which has been studied recently to evaluate the evolutionary relationship in distance between two biological species since block-interchange can be considered as a generalization of transposition. However, for genomes consisting of multiple chromosomes, their evolutionary history should also include events of chromosome fusions and fissions, where fusion merges two chromosomes into one and fission splits a chromosome into two. Results: In this paper, we study the problem of genome rearrangement between two genomes of circular and multiple chromosomes by considering fusion, fission and block-interchange events altogether. By use of permutation groups in algebra, we propose an O(n(2)) time algorithm to efficiently compute and obtain a minimum series of fusions, fissions and block-interchanges required to transform one circular multi-chromosomal genome into another, where n is the number of genes shared by the two studied genomes. In addition, we have implemented this algorithm as a web server, called FFBI, and have also applied it to analyzing by gene orders the whole genomes of three human Vibrio pathogens, each with multiple and circular chromosomes, to infer their evolutionary relationships. Consequently, our experimental results coincide well with our previous results obtained using the chromosome-by-chromosome comparisons by landmark orders between any two Vibrio chromosomal sequences as well as using the traditional comparative analysis of 16S rRNA sequences. Conclusion: FFBI is a useful tool for the bioinformatics analysis of circular and multiple genome rearrangement by fusions, fissions and block-interchanges.
Common stabilizers for linear control systems in the presence of actuators outage
(2006-06-15)
Liang, Yew-Wen
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Liaw, Der-Cherng
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電控工程研究所
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Institute of Electrical and Control Engineering
Issue concerning the existence of common stabilizers for a linear control system experiences actuators. outage are presented. The possible outage of actuators examined in this study are not restricted to a pre-specified set. By finding Common quadratic-type Lyapunov functions. we obtain sufficient conditions for the existence of common stabilizers. For cases of which all the possible failed actuators belonged to a pre-specified set. the results presented in this paper agree with those obtained by Veillette in 1995. The control gain of common stabilizer for non-nested case is explicitly derived to guarantee system stability. A simplified checking condition for the existence of common stabilizers is also obtained for the extreme case when only single actuator can normally operate. (c) 2005 Elsevier Inc. All rights reserved.
管管作品三首
(2006-06-15)
管管
Epoxy/polyhedral oligomeric silsesquioxane nanocomposites from octakis(glycidyidimethylsiloxy)octasilsesquioxane and small-molecule curing agents
(2006-06-15)
Liu, YL
;
Chang, GP
;
Hsu, KY
;
Chang, FC
;
應用化學系
Epoxy/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were obtained from octakis(glycidyldimethylsiloxy)octasilsesquioxane (OG) and diglycidyl ether of bisphenol A cured with small-molecule curing agents of diethylphosphite (DEP) and dicyandiamide (DICY). An increase in the POSS contents of the nanocomposites and an improvement in the nanocomposite homogeneity were observed with the use of the small-molecule curing agents. Phosphorus in DEP and nitrogen in DICY also performed synergism with POSS for thermal stability enhancement and flammability improvement in the nanocomposites. The nanocomposites possessing high OG contents exhibited good thermal stability, improved flammability, and high storage moduli. (c) 2006 Wiley Periodicals, Inc.
管管作品三首
(2006-06-15)
管管
Tool replacement for production with a low fraction of defectives
(2006-06-15)
Pearn, WL
;
Hsu, YC
;
Wu, CW
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In manufacturing industry, the tool replacement cost is, in many cases, a significant portion of the production cost. Early tool replacement increases the production cost. Overdue tool replacement, however, results in poor production quality. Accordingly, improving production quality while maintaining a low production cost is essential. The index C-pk is regarded as a yield-based index. For a fixed C-pk value, the production yield and fraction of defectives can be calculated. In this paper, we present an analytical approach using C-pk to determine the optimal tool replacement time. An accurate process capability must be calculated, particularly when the data contain assignable cause variation. Tool wear is a dominant and inseparable component in many machining processes (a systematic assignable cause), and ordinary capability measures become inaccurate because process data are contaminated by the assignable cause variation. Considering process capability changes dynamically, an estimator of C-pk is investigated. The closed form of the exact sampling distribution is derived. An effective tool management procedure for determining the optimal tool replacement time is presented for processes with a low fraction of defectives. For illustrative purposes, an application example involving tool wear is presented.