Browsing by Issue Date, starting with "2006-04-17"

Now showing 1 - 20 of 63390

General method to solution-process multilayer polymer light-emitting diodes
(2006-04-17)
Tseng, SR
;
Lin, SC
;
Meng, HF
;
Liao, HH
;
Yeh, CH
An intermediate liquid buffer layer is introduced to overcome the dissolution problem of solution-processed multilayer conjugated polymer light-emitting diodes. This method can be applied to arbitrary combinations of polymers with no restriction on solvents. As an example, a hole-blocking layer is successfully spin coated on the common p-type emissive polymer layers. One green- and two blue-emitting polymers are chosen as the emissive layers. The electron-hole balance and efficiency are significantly improved by the addition of hole-blocking layer. The electroluminescence efficiency can be increased up to nine times, while the luminance up to seven times. In particular, 1.5 cd/A is obtained for deep blue emission from poly(9,9-dioctyl-fluorene) with 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene spin coated as the hole-blocking material. (c) 2006 American Institute of Physics.
Ultrafast carrier capture and relaxation in modulation-doped InAs quantum dots
(2006-04-17)
Sun, KW
;
Kechiantz, A
;
Lee, BC
;
Lee, CP
;
應用化學系
We report investigations on carrier capture and relaxation processes in undoped and modulation-doped InAs/GaAs self-assembled quantum dots (QDs) by using time-resolved spectroscopy technique with a time resolution of similar to 200 fs. We find that carrier capture and relaxation in the ground state of the charged QD are faster compared to the undoped dots even at an excitation level as low as 1x10(10) cm(-2). It is attributed to the triggering of the vibrating polarization field induced by the presence of cold carriers in the doped dots. The rate of an electron been captured by a positively charged QD is also calculated based on our proposed model. (c) 2006 American Institute of Physics.
Toxicity assessment of pesticides to Pseudokirchneriella subcapitata under air-tight test environment
(2006-04-17)
Yeh, HJ
;
Chen, CY
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環境工程研究所
;
Institute of Environmental Engineering
This paper presents the toxicity data of seven pesticides including atrazine, parathion, dichlorvos, malathion, fenthion, 2-methyl-4-chiorophenoxyacetic acid, and pentachlorophenol on Pseudokirchneriella subcapitata based on a new algal toxicity testing technique conducted under air-tight environment. The dissolved oxygen production and the cell density were adopted as the response endpoints. Median effective concentrations (EC50) range from 0.0035 to 3.40 mg/L (DO production) and from 0.0067 to 3.12 mg/L (cell density). No-observed-effect concentration (NOEC) was determined using the Dunnett's test. NOEC values are with in the range of 0.001-1.20 mg/L. In general, the two test endpoints revealed similar sensitivities. From comparisons of literature data also based on Pseudokirchneriella subcapitata, it is clear that conventional batch tests tend to underestimate the toxicity of pesticides due to their open test environment. Closed-system tests, i.e., microplate test, respirometer test, and our BOD-bottle test, generally provide better assessment to the effects of pesticides. Data based on our test method reveals much higher toxicity (3-100 times) than that from the conventional batch tests. Furthermore, for organophosphorus insecticides, results from the present study show that Pseudokirchneriella subcapitata is less sensitive than Daphnia magna and rainbow trout, but is more susceptible than fathead minnow. The closed-system test applied in this study provides more adequate assessment for the toxicity of pesticides than the conventional batch tests. (c) 2005 Elsevier B.V. All rights reserved.
Field propagation of a metallic grid slab that acts as a metamaterial
(2006-04-24)
Tsao, CH
;
Chern, JL
;
光電工程學系
;
Department of Photonics
A metallic grid slab has been shown to work as a novel metamaterial which can shape the divergent field emitted from an embedded monopole microwave antenna into a directive transmission at a specific frequency. The transmission of such subwavelength slab remains an issue of challenge. In this work, we experimentally investigate the transmitted behavior of such subwavelength grid slab to explore the underlying mechanism of wave propagation. It is found that there is a large tolerance of directive emission even with a tilted slab. The deviation along the directive emission direction is analyzed based on the interference theory. (c) 2005 Elsevier B.V. All rights reserved.
Effect of Al-trace dimension on Joule heating and current crowding in flip-chip solder joints under accelerated electromigration
(2006-04-24)
Liang, SW
;
Chang, YW
;
Chen, C
;
材料科學與工程學系
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Department of Materials Science and Engineering
Three-dimensional thermoelectrical simulation was conducted to investigate the influence of Al-trace dimension on Joule heating and current crowding in flip-chip solder joints. It is found that the dimension of the Al-trace effects significantly on the Joule heating, and thus directly determines the mean time to failure (MTTF). Simulated at a stressing current of 0.6 A at 70 degrees C, we estimate that the MTTF of the joints with Al traces in 100 mu m width was 6.1 times longer than that of joints with Al traces in 34 mu m width. Lower current crowding effect and reduced hot-spot temperature are responsible for the improved MTTF. (c) 2006 American Institute of Physics.
影子
(2006-04-24)
管管
Wireless LAN medium access controller supporting mode change and mode change method thereof
(2006-04-27)
Lin, Yen-Liang
;
Chang, Hsung-Pin
;
Chang, Ruei-Chuan
A wireless LAN medium access controller supporting mode change and the mode change method thereof are proposed. A physical layer detects signal strength in the environment and writes a mode index value of the stronger signal into a register. When the written mode index value is different from a mode index value in the communication system, a medium access controller is informed to perform mode change. The physical layer then sends out an interrupt signal to a central processor and sends the mode index value to the central processor for comparison via a DMA module and a memory. An interface module is used to access the mode index value in the memory for providing an external interface for the medium access control layer. When the mode index value doesn't conform to the signal in the environment, a software layer in the medium access controller is used for mode change.
A robust approach to t linear mixed models applied to multiple sclerosis data
(2006-04-30)
Lin, TI
;
Lee, JC
;
統計學研究所
;
資訊管理與財務金融系註：原資管所+財金所
;
Institute of Statistics
We discuss a robust extension of linear mixed models based on the multivariate t distribution. Since longitudinal data are successively collected over time and typically tend to be autocorrelated, we employ a parsimonious first-order autoregressive dependence structure for the within-subject errors. A score test statistic for testing the existence of autocorrelation among the within-subject errors is derived. Moreover, we develop an explicit scoring procedure for the maximum likelihood estimation with standard errors as a by-product. The technique for predicting future responses of a subject given past measurements is also investigated. Results are illustrated with real data from a multiple sclerosis clinical trial. Copyright (c) 2005 John Wiley & Sons, Ltd.
Detection of discriminative sequence motifs in proteins obtained from prokaryotes grown at various temperatures
(2006-04-30)
Wu, LC
;
Horng, JT
;
Huang, SL
;
Huang, HD
;
Liu, BJ
Recent investigations on the stability of proteins have demonstrated various structural factors, but few have considered sequence factors such as protein motifs. These motifs represent highly conserved regions and describe critical regions that may only exist on proteins that remain functional at high temperatures. This investigation presents a method for identifying and comparing corresponding mesophilic and thermophilic sequence motifs between protein families. Discriminative motifs that are conserved only in the mesophilic or thermophilic subfamily are identified. Analysis of the results shows that, although the subfamilies of most protein families share similar motifs, some discriminative motifs are present in particular thermophilic/mesophilic subfamilies. The thermophilic discriminative motifs are conserved only in thermophilic organisms, revealing that physiochemical principles support thermostability. (c) 2006 Wiley Periodicals, Inc.
Wavelength-interleaving bidirectional transmission system using unidirectional amplification in a 5 x 100 km recirculating loop
(2006-05-01)
Huang, MF
;
Feng, KM
;
Chen, JJ
;
Lin, TY
;
Wei, CC
This investigation presents a novel 50-GHz interleaved bidirectional transmission system with eight wavelengths that uses four-port interleavers in a bidirectional recirculating loop. This bidirectional configuration shares optical components in the fiber network and an interleaver is utilized to enable unidirectional amplification in an erbium-doped fiber amplifier to block noise associated with Rayleigh backscattering. After bidirectional transmission through 500-km LEAF fibers in the recirculating loop, power penalties of less than 2.5 dB, were achieved at 10 Gb/s for all channels.
Modeling multizoned layer to improve light efficiency of organic light-emitting diode display
(2006-05-01)
Wei, AC
;
Shieh, HPD
;
光電工程學系
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顯示科技研究所
;
Department of Photonics
A multizoned light-enhanced layer (MZ-LEL) superimposed on an organic light-emitting diode (OLED) display has been demonstrated to increase the level of the light out-coupling efficiency in the normal direction. Such an MZ-LEL has a specific profile, which has been fabricated with sufficient accuracy. Simultaneously, this study has shown that by combining Fresnel's equation into an existing ray-tracing model, the level of accuracy in the construction of the model can be increased. Such a new model applied to a previous study has reduced the modeling deviation from 50 to 4%. It has been found that a 70 x 70 pixel OLED panel laminated with an array-patterned MZ-LEL (ALEL) exhibits a gain factor of 1.28. which is consistent with the simulated value of 1.32.
10-Gb/s modulator drivers with local feedback networks
(2006-05-01)
Li, DU
;
Tsai, CM
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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 novel intrinsic collector-base capacitance (C(CB)) feedback network (ICBCFN) was incorporated into the conventional cascode and series-connected voltage balancing (SCVB) circuit configurations to implement 10-Gb/s modulator drivers. The drivers fabricated in 0.35-mu m SiGe BiCMOS process could generate 9 V(PP) differential output swings with rise/fall time of less than 29 ps. Also, the ICBCFN was modified as an intrinsic drain-gate capacitance feedback network (IDGCFN) to implement drivers with differential output swing of 8 V(PP) in 0.18-mu m CMOS process. The power consumption is as low as 0.6 W. The present work shows that the driving capability is greater than that of the currently reported Silicon-based drivers.
Distribution and antifungal susceptibility of Candida species isolated from different age populations in Taiwan
(2006-05-01)
Yang, Yun-Liang
;
Cheng, Hsiao-Hsu
;
Lo, Hsiu-Jung
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生物科技學系
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Department of Biological Science and Technology
A total of 3926 yeast isolates were isolated from 24 hospitals participating in the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) from July to September 2002. Candida albicans (69.1%) was the most common species, followed by Candida tropicalis (12.9%), Candida glabrata (8.3%), Candida parapsilosis (2.7%), Candida krusei (0.6%), and others (6.4%). To study the distribution and antifungal susceptibility of Candida species according to sources and patient ages, we have collected and analyzed the clinical data of 861 isolates. Of those 861 isolates, urine was the most common source (40%) followed by sputum (22.1%), blood (13.5%), central venous catheter (5.5%), wound (5.2%), and others (13.7%). With increasing age, we observed a significant increase in the percentage of isolates from urine (P = 0.00005) and a parallel reduction from blood (P = 0.009). As expected, more elder patients were hospitalized than younger ones (P = 0.05). In total, 2.7% and 1.9% of isolates were resistant to amphotericin B and fluconazole, respectively. Antifungal susceptibilities of isolates from different age groups were not significantly different.
Asymmetric 2+1 pass stereo matching algorithm for real images
(2006-05-01)
Chu, C
;
Chang, CC
;
資訊工程學系
;
Department of Computer Science
An asymmetric 2+1 pass stereo matching algorithm is proposed for generating a depth map from the input of two real stereo images. In the first pass, the Canny edge detector is used to acquire edge images from the inputs. Component images are then generated from the edge images. The edges of each component in the left component image are cut to obtain asymmetric left and right component images. The concept of a disparity-space image (DSI) by components is introduced and dynamic programming (DP) techniques are applied to match the asymmetric left and right component images. In the second pass, the previous DSI is modified, applying the DP methods to acquire the matched pixel pairs of the matched component pairs, and to generate ground control pairs (GCPs). In the final pass, these GCPs are incorporated into the DP algorithms to determine the optimal path and acquire the depth image. The results show that the proposed approach produces reliable and efficient matching and preserves the shapes of objects effectively for real stereo images. The proposed algorithm makes contours clearer than other conventional methods for real stereo images. (C) 2006 Society of Photo-Optical Instrumentation Engineers.
Maximum likelihood estimates and confidence intervals of an M/M/R queue with heterogeneous servers
(2006-05-01)
Wang, TY
;
Ke, JC
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Wang, KH
;
Ho, SC
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工業工程與管理學系
This paper studies maximum likelihood estimates as well as confidence intervals of an M/M/R queue with heterogeneous servers under steady-state conditions. We derive the maximum likelihood estimates of the mean arrival rate and the three unequal mean service rates for an M/M/3 queue with heterogeneous servers, and then extend the results to an M/M/R queue with heterogeneous servers. We also develop the confidence interval formula for the parameter rho, the probability of empty system P-0, and the expected number of customers in the system E[N], of an M/M/R queue with heterogeneous servers.
An all-optical 2R regenerator using a compact self-seeded Fabry-Perot laser diode incorporated in a bidirectional EDFA
(2006-05-01)
Chien, HC
;
Lee, CC
;
Chi, S
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光電工程學系
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Department of Photonics
An all-optical 2R regenerator, based on a compact self-seeded Fabry-Perot laser diode with a 10-mm-long embedded fiber Bragg grating cavity, and a bidirectional erbium-doped fiber amplifier, is proposed and experimentally demonstrated to execute all-optical 211 regeneration at 10 Gb/s. Compared with the conventional 111 regeneration, the proposed scheme has achieved significant 6.4-dB improvement of power penalty at bit-error ratio = 10(-9) in the transmission experiment over 100-km standard single-mode fiber.
反應性模板之製備方法、奈米材料之製備方法及奈米材料
(2006-05-01)
裘性天
;
李紫原
;
王隆昇
;
盛焙蓀
一種在一不干擾反應的惰性氣體氛圍下，將反應物A均勻塗佈於具特殊形貌的模板T上，以使形成一製備奈米材料用之具有反應物A的模板TA，於反應器中不干擾反應的惰性氣體氛圍下，使模板TA之反應物A與反應物B起反應，以製備一具有生成物C的反應性模板TC；以及於不干擾反應的惰性氣體氛圍下，使用該反應性模板，利用溶劑將具有生成物C的反應性模板TC中之模板T予以移除，使形成奈米材料之製備方法，及所製得的具有與模板T相同之特殊形貌的奈米材料。
Various analyses of specific heat for the order parameter of superconductor Na(0.35)coO(2) center dot 1.3H(2)O
(2006-05-01)
Sun, CP
;
Lin, JY
;
Kang, YC
;
Huang, CL
;
Takada, K
Low-temperature specific-heat data C(T) of two Na0.35CoO2. 1.3H(2)O samples (I and II) with temperature T down to 0.6 K without and with magnetic field of 8T are presented. The normal-state linear coefficient of specific heat gamma(n) Debye temperature Theta D, superconducting transition temperature T-c, specific heat jump at T-c, Delta C/T-gamma ns(c). and superconducting volume of fraction (SVF) are 14.89 mJ/mol K-2, 503, 4.7 K, 1.96, and 26.6% for sample I and 13.94 mJ/mol K-2, 362, 4.5 K, 1.45. and 47.4% for sample II, respectively. Because the superconducting properties may depend on the water content of sample, it is found that the better quality (higher SVF) of sample, the nodal order parameter is better than BCS isotropic s-wave model in describing the gap function of this interesting compound Na0.35CoO2. 1.3H(2)O. (c) 2006 Elsevier B.V. All rights reserved.
Strategies for technology platforms
(2006-05-01)
Yang, C
;
Jiang, S
;
經營管理研究所
;
Institute of Business and Management
This management framework permits integrating positioning, competencies and acquisitions in the context of a dynamic process of platform strategy. The integration method suggested is the platform-market matrix, which can be used to capture the market dynamics and the platform dynamics simultaneously. In addition, with the proposed framework a company can quickly choose the action ,odes or platform strategies in an appropriate setting, along with their supporting strategies.
Cascaded trellis-based rate-distortion control algorithm for MPEG-4 advanced audio coding
(2006-05-01)
Yang, CH
;
Hang, HM
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a few low-complexity and high-performance rate-distortion control algorithms for MPEG-4 Advanced Audio Coding (AAC) are proposed. One key element in producing good quality compressed audio particularly at medium and low rates is a high performance rate-distortion controller in the audio encoder. Although the trellis-based rate-distortion control algorithms previously proposed can achieve a praiseworthy performance, their computational complexity is extremely high. Therefore, for practical applications, it is very desirable to achieve a similar performance at a much lower complexity. Two types of techniques are proposed in this paper to reduce the computational burden of the trellis-based algorithms. One is splitting a very heavy calculation stage into two sequential steps with much less computation. The other is reducing the candidates in the trellis for parameter search. Together, when applicable, our approach achieves a similar coding performance (audio quality) but requires less than 1/1000 complexity in computation.