Browsing by Issue Date, starting with "2010-09-10"

Now showing 1 - 20 of 45387

A Fully Integrated Built-In Self-Test Sigma-Delta ADC Based on the Modified Controlled Sine-Wave Fitting Procedure
(2010-09-10)
Hong, Hao-Chiao
;
Su, Fang-Yi
;
Hung, Shao-Feng
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper demonstrates the first fully integrated built-in self-test (BIST) Sigma-Delta analog-to-digital converter (ADC) chip to the best of our knowledge. The ADC under test (AUT) comprises a second-order design-for-digital-testability Sigma-Delta modulator and a decimation filter. The purely digital BIST circuitry conducts single-tone tests for the signal-to-noise-and-distortion ratio (SNDR), the dynamic range, the offset, and the gain error of the AUT. The BIST design is based on the proposed modified controlled sine-wave fitting procedure to address the component overload issues, reduce the setup parameter numbers, and eliminate the need for parallel multipliers. The total gate count of the whole BIST circuitry is only 13 300. The hardware overhead is much less than the BIST design using the traditional fast Fourier transform (FFT) analysis. Measurement results show that the peak SNDR results of the proposed BIST design and the conventional FFT analysis are 75.5 and 75.3 dB, respectively. The subtle SNDR difference is already within analog test uncertainty. The BIST Sigma-Delta ADC achieves a digital test bandwidth higher than 17 kHz, very close to the rated 20-kHz bandwidth of the AUT.
應用於遞回式解碼法之多重檢測終止機制及其與方塊間重排渦輪碼解碼器之整合
(2010-09-11)
鄭延修
;
蘇育德
一種應用於遞回式解碼法之多重檢測終止機制及其與方塊間重排渦輪碼解碼器之整合。由於渦輪碼係為現代通訊系統中很有用的編碼技術，遞回解碼的概念應用範圍很廣，如渦輪等化器。然而，遞回次數影響功率消耗。因此，本發明係為一可應用於使用遞回式解碼法的解碼系統之多重檢測終止機制，且進而改善方塊間排列渦輪碼的效能。
Phosphor-converted LED modeling by bidirectional photometric data
(2010-09-13)
Hung, Chien-Hsiang
;
Tien, Chung-Hao
;
光電工程學系
;
顯示科技研究所
;
光電工程研究所
For the phosphor-converted light-emitting diodes (pcLEDs), the interaction of the illuminating energy with the phosphor would not just behave as a simple wavelength-converting phenomenon, but also a function of various combinations of illumination and viewing geometries. This paper presents a methodology to characterize the converting and scattering mechanisms of the phosphor layer in the pcLEDs by the measured bidirectional scattering distribution functions (BSDFs). A commercially available pcLED with conformal phosphor coating was used to examine the validity of the proposed model. The close agreement with the measurement illustrates that the proposed characterization opens new perspectives for phosphor-based conversion and scattering feature for white lighting uses. (C) 2010 Optical Society of America
Phonon thermal conductivity suppression of bulk silicon nanowire composites for efficient thermoelectric conversion
(2010-09-13)
Chen, Ting-Gang
;
Yu, Peichen
;
Chou, Rone-Hwa
;
Pan, Ci-Ling
;
光電工程學系
Vertically-aligned silicon nanowires (SiNWs) that demonstrate reductions of phonon thermal conductivities are ideal components for thermoelectric devices. In this paper, we present large-area silicon nanowire arrays in various lengths using a silver-induced, electroless-etching method that is applicable to both n- and p-type substrates. The measured thermal conductivities of nanowire composites are significantly reduced by up to 43%, compared to that of bulk silicon. Detailed calculations based on the series thermal resistance and phonon radiative transfer models confirm the reduction of thermal conductivity not only due to the increased air fraction, but also the nanowire size effect, suggesting the soundness of employing bulk silicon nanowire composites as efficient thermoelectric materials. (C) 2010 Optical Society of America
Improved optical transmission and current matching of a triple-junction solar cell utilizing sub-wavelength structures
(2010-09-13)
Chiu, M. -Y.
;
Chang, C. -H.
;
Tsai, M. -A.
;
Chang, F. -Y.
;
Yu, Peichen
Sub-wavelength antireflective structures are fabricated on a silicon nitride passivation layer of a Ga(0.5)In(0.5)P/GaAs/Ge triple-junction solar cell using polystyrene nanosphere lithography followed by anisotropic etching. The fabricated structures enhance optical transmission in the ultraviolet wavelength range, compared to a conventional single-layer antireflective coating (ARC). The transmission improvement contributes to an enhanced photocurrent, which is also verified by the external quantum efficiency characterization of the fabricated solar cells. Under one-sun illumination, the short-circuit current of a cell with sub-wavelength structures is enhanced by 46.1% and 3.4% due to much improved optical transmission and current matching, compared to cells without an ARC and with a conventional SiN(x) ARC, respectively. Further optimizations of the sub-wavelength structures including the periodicity and etching depth are conducted by performing comprehensive calculations based on a rigorous couple-wave analysis method. (C) 2010 Optical Society of America
Examining the large-time wellbore flux of constant head test
(2010-09-14)
Yeh, Hund-Der
;
Wang, Chih-Tse
;
Smith, Stefan G. Llewellyn
;
環境工程研究所
;
Institute of Environmental Engineering
The function 1/[p ln (p/lambda)] comes from the wellbore flux solution in the Laplace domain for a constant head aquifer test when the Laplace variable p is small. The resulting inverse Laplace transform v(lambda t), representing the large-time wellbore flux, grows exponentially with time, which does not agree with the physical behavior of the wellbore flux. Based on this result, Chen and Stone (1993) asserted that the well-known relationship of small p-large t may fail to yield the correct large-time asymptotic solution. Yeh and Wang (2007) pointed out that the large-time wellbore flux is not n(lambda t) if the inversion of 1/[p ln (p/lambda)] is subject to the constraint Re p > lambda. Chen (2009) subsequently questioned the necessity of imposing this constraint on the Laplace transform in the inversion of the large-time wellbore flux. Motived by Chen's comment, we reexamine the inversion of 1/[p ln (p/lambda)] and demonstrate that this contradictory issue originates from a spurious pole introduced when applying the small p-large t correspondence to the Laplace domain solution. We explain why this occurs and why the actual wellbore flux at large times is proportional to the function N(lambda t), known as Ramanujan's integral. The function N(lambda t) does decay at large time, which agrees with the steady state wellbore flux of the constant head test.
A Thieno[3,4-c]pyrrole-4,6-dione-Based Donor-Acceptor Polymer Exhibiting High Crystallinity for Photovoltaic Applications
(2010-09-14)
Yuan, Mao-Chuan
;
Chiu, Mao-Yuan
;
Liu, Shih-Pin
;
Chen, Chia-Min
;
Wei, Kung-Hwa
Slope control device capable of predicting uniform-current-sharing level and method thereof
(2010-09-14)
Ho
;
Hsin-Hsin
;
Chen
;
Ke-Horng
;
Hsieh
The present invention discloses a slope control device capable of predicting uniform-current-sharing level and method thereof which can be applied in a redundancy or distributed power system for providing better uniform-current-sharing ability. The device comprises a high linearity transconductor circuit, a slope adjusting circuit and an incremental output voltage circuit. The invention applies either a transconductor parameter or a feedback resistor to increase the droop gain and therefore the current deviation between two power supply modules is reduced. The invention further raises the output voltage step by step to ensure that the output voltage meet the requirement of allowable minimum output voltage according to increment of load current.
Capacity-based compressed mode control method for inter-system handover in universal mobile telecommunication system
(2010-09-14)
Huang
;
Ching Yao
;
Chang
;
Cheng Ta
;
Ho
The Inter-System handover is one of the key features in the third generation cellular systems. The compressed mode, with variable transmission gaps and power levels, is standardized to support the inter-frequency system handover. To minimize the use of system resources while maintaining the border-cell handover quality, a capacity-based compressed mode control method of the present invention is proposed. Considering the tradeoff between the capacity and the communication quality, the control method can adaptively manage the compressed mode operation based on the potential impacts on the capacity and the effectiveness of the compressed mode measurement. The present invention will improve the effectiveness and performance of the compressed mode operation.
Optical element apparatus for two-dimensional controllable localized partition backlight module
(2010-09-14)
Tien
;
Chung-Hao
;
Lu
;
Yen-Hsing
;
Cheng
The optical element apparatus for two-dimensional controllable localized partition backlight module is disclosed. The optical element apparatus comprises of a plurality of optical units which include a plurality of point light sources, light guides and collimating sheets. The point light source is located at the center of the light guide. The light guide includes the incident surface, the bottom place connecting with the light incident surface, and the light output surface. There are micro structures on the bottom place of the light guide and the top surface of the collimating sheet.
Synthesis and Characterization of a Thiadiazole/Benzoimidazole-Based Copolymer for Solar Cell Applications
(2010-09-15)
Chen, Guan-yu
;
Lan, Shang-che
;
Lin, Po-yu
;
Chu, Chih-wei
;
Wei, Kung-hwa
In this study, we synthesized a new polymer, PCTDBI, containing alternating carbazole and thiadiazole-benzoimidazole (TDBI) units. This polymer (number-average molecular weight - 25,600 g mol(-1)), which features a planar imidazole structure into the polymeric main chain, possesses reasonably good thermal properties (T(g) = 105 degrees C; T(d) = 396 degrees C) and an optical band gap of 1.75 eV that matches the maximum photon flux of sunlight. Electrochemical measurements revealed an appropriate energy band offset between the polymer's lowest unoccupied molecular orbital and that of PCBM, thereby allowing efficient electron transfer between the two species. A solar cell device incorporating PCTDBI and PCBM at a blend ratio of 1: 2 (w/w) exhibited a power conversion efficiency of 1.20%; the corresponding device incorporating PCTDBI and PC(71)BM (1: 2, w/w) exhibited a PCE of 1.84%. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4456-4464, 2010
Characteristics of emission polarization in a-plane nanorods embedded with InGaN/GaN multiple quantum wells
(2010-09-15)
Li, J. C.
;
Lu, T. C.
;
Huang, H. M.
;
Chan, W. W.
;
Kuo, H. C.
Nonpolar (a-plane) GaN nanorod arrays with embedded In(x)Ga(1-x)N/GaN (x=0.09, 0.14, 0.24, and 0.30) multiple quantum wells (MQWs) grown on r-plane sapphire have been fabricated successfully by self-assembled Ni nanomasks and subsequent inductively coupled plasma reactive-ion etching. After nanorod fabrications, the polarization ratio of the emission from MQWs with lower indium composition (x=0.09 and 0.14) slightly decreases but apparently increases by at most 79% for the samples with higher indium composition (x=0.24 and 0.30). Competition between the effect of multiple scattering, strain relaxation and reduction in localized centers, expected in a-plane MQW samples, are attributed to the variations in the polarization ratios after the nanorod formation. (c) 2010 American Institute of Physics. [doi:10.1063/1.3483239]
Compensation effect and differential capacitance analysis of electronic energy band structure in relaxed InAs quantum dots
(2010-09-15)
Chen, J. F.
;
Chen, Ross C. C.
;
Chiang, C. H.
;
Hsieh, M. C.
;
Chang, Y. C.
The use of a differential capacitance technique for analyzing the effect of strain relaxation on the electronic energy band structure in relaxed InAs self-assembled quantum dots (QDs) is presented. Strain relaxation is shown to induce a deep defect state and compensate the ionized impurity in the bottom GaAs layer, leading to a double depletion width and a long emission time. An expression of capacitance at different frequency and voltage is derived for analyzing the experimental data. It has been shown that the relationship between the low-frequency and high-frequency capacitances can be well explained by a Schottky depletion model with a compensated concentration in the bottom GaAs layer. A simple expression is presented to account for the modulation of the free electrons in the top GaAs layer. This capacitance analysis shows a long low-energy tail for the electron ground state, suggesting not very uniform strain relaxation. The results of this study illustrate a carrier compensation effect of the defect state on the electronic energy band structure near the QDs. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467938]
Improvement in output power of a 460 nm InGaN light-emitting diode using staggered quantum well
(2010-09-15)
Liao, Chih-Teng
;
Tsai, Miao-Chan
;
Liou, Bo-Ting
;
Yen, Sheng-Horng
;
Kuo, Yen-Kuang
Staggered quantum well structures are studied to eliminate the influence of polarization-induced electrostatic field upon the optical performance of blue InGaN light-emitting diodes (LEDs). Blue InGaN LEDs with various staggered quantum wells which vary in their indium compositions and quantum well width are theoretically studied and compared by using the APSYS simulation program. According to the simulation results, the best optical characteristic is obtained when the staggered quantum well is designed as In(0.20)Ga(0.80)N (1.4 nm)-In(0.26)Ga(0.74)N (1.6 nm) for blue LEDs. Superiority of this novelty design is on the strength of its enhanced overlap of electron and hole wave functions, uniform distribution of holes, and suppressed electron leakage in the LED device. (C) 2010 American Institute of Physics. [doi:10.1063/1.3471804]
Stability of nanoscale twins in copper under electric current stressing
(2010-09-15)
Chen, Kuan-Chia
;
Wu, Wen-Wei
;
Liao, Chien-Neng
;
Chen, Lih-Juann
;
Tu, K. N.
Migration of {112} incoherent twin boundary (ITB) in nanotwinned Cu under electric current stressing has been observed using in situ high-resolution transmission electron microscopy. The current-driven ITB migration is found to be four orders of magnitude faster than that driven thermally. We propose that electric current plays a role of shuffling Cu atoms at ITB/coherent twin boundary junctions, which enhances nucleation of {112} steps and facilitates twin boundary migration in Cu. By understanding how twin boundaries respond to electric current force we shall be able to trace the property change in nanotwinned Cu under electric current stressing, which would be an essential assessment of interconnect reliability. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3483949]
Spectrofluorometric assay for monoamine-preferring phenol sulfotransferase (SULT1A3)
(2010-09-15)
Lu, Lu-Yi
;
Hsu, Yen-Chang
;
Yang, Yuh-Shyong
;
生物科技學系
;
Department of Biological Science and Technology
A continuous and real-time fluorometric assay for monoamine-preferring phenol sulfotransferase (SULT1A3) was developed. The methodology was based on the coupling of SULT1A1 to regenerate 3'-phosphoadenosine-5'-phosPhosulfate (PAPS) using 4-methylumbelliferyl sulfate (MUS) as a sulfuryl group donor. The fluorophore product (4-methylumbelliferone. MU) was continuously produced and monitored when SULT1A3 catalyzed dopamine sulfation with PAPS. The optimal conditions of this turnover reaction and substrate inhibition of SULT1A3 were also determined. This coupled-enzyme assay allows the continuous measurement of initial reaction velocity and the sensitivity is comparable to that of end-point radioactive isotope assay. (C) 2010 Elsevier Inc. All rights reserved.
Stability of nanoscale twins in copper under electric current stressing
(2010-09-15)
Chen, Kuan-Chia
;
Wu, Wen-Wei
;
Liao, Chien-Neng
;
Chen, Lih-Juann
;
Tu, K. N.
Migration of {112} incoherent twin boundary (ITB) in nanotwinned Cu under electric current stressing has been observed using in situ high-resolution transmission electron microscopy. The current-driven ITB migration is found to be four orders of magnitude faster than that driven thermally. We propose that electric current plays a role of shuffling Cu atoms at ITB/coherent twin boundary junctions, which enhances nucleation of {112} steps and facilitates twin boundary migration in Cu. By understanding how twin boundaries respond to electric current force we shall be able to trace the property change in nanotwinned Cu under electric current stressing, which would be an essential assessment of interconnect reliability. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3483949]
Characteristics of emission polarization in a-plane nanorods embedded with InGaN/GaN multiple quantum wells
(2010-09-15)
Li, J. C.
;
Lu, T. C.
;
Huang, H. M.
;
Chan, W. W.
;
Kuo, H. C.
Nonpolar (a-plane) GaN nanorod arrays with embedded In(x)Ga(1-x)N/GaN (x=0.09, 0.14, 0.24, and 0.30) multiple quantum wells (MQWs) grown on r-plane sapphire have been fabricated successfully by self-assembled Ni nanomasks and subsequent inductively coupled plasma reactive-ion etching. After nanorod fabrications, the polarization ratio of the emission from MQWs with lower indium composition (x=0.09 and 0.14) slightly decreases but apparently increases by at most 79% for the samples with higher indium composition (x=0.24 and 0.30). Competition between the effect of multiple scattering, strain relaxation and reduction in localized centers, expected in a-plane MQW samples, are attributed to the variations in the polarization ratios after the nanorod formation. (c) 2010 American Institute of Physics. [doi:10.1063/1.3483239]
Synthesis and Characterization of PEG-PCL-PEG Triblock Copolymers as Carriers of Doxorubicin for the Treatment of Breast Cancer
(2010-09-15)
Cuong, Nguyen-Van
;
Hsieh, Ming-Fa
;
Chen, Yung-Tsung
;
Liau, Ian
;
應用化學系分子科學碩博班
Triblock copolymers of monomethoxy poly(ethylene glycol) (mPEG) and epsilon-caprolactone (CL) were prepared with varying lengths of poly(E-caprolactone) (PCL) compositions and a fixed length of mPEG segment. The molecular characteristics of triblock copolymers were characterized by NMR, gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). These amphiphilic linear copolymers based on PCL hydrophobic chain and hydrophilic mPEG ending, which can self-assemble into nanoscopic micelles with their hydrophobic cores, encapsulated doxorubicin (DOX) in an aqueous solution. The particle size of prepared micelles was around 40-92 nm. The DOX loading content and DOX loading efficiency were from 3.7-7.4% to 26-49%, respectively. DOX-released profile was pH-dependent and faster at pH 5.4 than pH 7.4. Additionally, the cytotoxicity of DOX-loaded micelles was found to be similar with free DOX in drug-resistant cells (MCF-7/adr). The great amounts of DOX and fast uptake accumulated into the MCF-7/adr cells from DOX-loaded micelles suggest a potential application in cancer chemotherapy. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3694-3703, 2010
CONTROL METHOD OF TRANSMITTING STREAMING AUDIO/VIDEO DATA AND ARCHITECTURE THEREOF
(2010-09-16)
HUANG, Ching-Yao
;
CHEN, Zhi-Zhan
;
LI, Chun-Hsiao
A control method and architecture for controlling transmission of streaming audio/video data are disclosed. The method uses a report transmission rate on a transmitter to reduce the playback latency on a receiver. The report transmission rate is determined according to an actual transmission rate and the residual data amount of the previous period of a transmitter buffer. The actual transmission rate is the minimum of an available transmission rate and a required transmission rate, which depends on the residual data amount and the report transmission rate. Therefore, the report transmission rate is adjusted according to the accumulation of residual data of transmitter buffer, which improves the playback latency.