Browsing by Issue Date, starting with "2007-03-15"

Now showing 1 - 20 of 60004

A highly sensitive system for urea detection by using CdSe/ZnS core-shell quantum dots
(2007-03-15)
Huang, Chin-Ping
;
Li, Yaw-Kuen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
An original and novel assay system with urease as a catalyst and CdSe/ZnS quantum dots (QDs) as an indicator has been developed for quantitative analysis of urea. By mixing urease and QDs, the determination of urea can be performed in a quantitative manner. The detection is based on the enhancement of QD photoluminescence (PL) intensity, which is correlated to the enzymatic degradation of urea. By controlling the buffer concentration and pH, PL enhancement due to the degradation of urea is linear in the urea concentration ranging from 0.01 to 100 mM. This property makes the urease/QDs system to be a promising urea-biosensing system. The newly developed system is a superior design and possesses many advantages, including its simple preparation, low cost, no enzyme immobilization required, high flexibility, and good sensitivity. (c) 2006 Elsevier B.V. All rights reserved.
Exploring the missing link among d-separable, d-separable and d-disjunct matrices
(2007-03-15)
Chen, Hong-Bin
;
Hwang, Frank K.
;
應用數學系
;
Department of Applied Mathematics
d-Disjunct matrices, (d) over bar -separable matrices and d-separable matrices are well studied in various problems including group testing, coding, extremal set theory and, recently, DNA sequencing. The implications from the first two matrices to the last one are well documented. This paper gives an implication of the other direction for the first time. (c) 2006 Elsevier B.X. All rights reserved.
管管作品六首
(2007-03-15)
管管
Acceleration of microwave-assisted enzymatic digestion reactions by magnetite beads
(2007-03-15)
Chen, Wei-Yu
;
Chen, Yu-Chie
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
In this study, we demonstrated that microwave-assisted enzymatic digestion could be greatly accelerated by multifunctional magnetite beads. The acceleration of microwave-assisted enzymatic digestion by the presence of the magnetite beads was attributable to several features of the beads. Their capacity to absorb microwave radiation leads to rapid heating of the beads. Furthermore, their negatively charged functionalities cause adsorption of proteins with opposite charges onto their surfaces by electrostatic interactions, leading to a concentration on the surfaces of the beads of proteins present in trace amounts in the solution. The adsorbed proteins are denatured and hence rendered vulnerable to enzymatic digestion and are digested on the beads. For microwave heating, 30 s was sufficient for carrying out the tryptic digestion of cytochrome c, in the presence of magnetite beads, while 1 min was adequate for tryptic digestion of myoglobin. The digestion products were characterized by MALDI-MS. This rapid enzymatic digestion allowed the entire time for identification of proteins to be greatly reduced. Furthermore, specific proteins present in trace quantities were enriched from the sample on the magnetite beads and could be rapidly isolated from the sample by employing an external magnetic field. These multiple roles of magnetite beads, as the absorber for microwave irradiation, the concentrating probe, and the agent for unfolding proteins, contributed to their capability of accelerating microwave-assisted enzymatic digestion. We also demonstrated that trypsin immobilized magnetite beads were suitable for use in microwave-assisted enzymatic digestion.
管管作品六首
(2007-03-15)
管管
管管作品六首
(2007-03-15)
管管
The use of sensitivity analysis in on-line aquifer parameter estimation
(2007-03-15)
Huang, Yen-Chen
;
Yeh, Hund-Der
;
環境工程研究所
;
Institute of Environmental Engineering
Generally, a pumping test requires a lot of effort and expense to perform the test and the drawdown is measured and analyzed for determining the aquifer parameters. The estimated aquifer parameters obtained from graphical approaches may not be in good accuracy if the pumping time is too short to give a good visual fit to the type curve. Yet, the problems of tong pumping time and required efforts can be significantly reduced if the drawdown data are measured and the parameters are simultaneously estimated on-Line. However, the drawdown behavior of the Leaky and unconfined aquifers in response to the pumping may have a time tag and the time to terminate the estimation may not be easily and quickly to decide when applying a parameter estimation model (PEM) on-Line to analyze the parameters. This study uses the sensitivity analysis to explore the influence period of each aquifer parameter to the pumping drawdown and the influence period is used as a guide in terminating the estimation when applying the PEM for on-line parameter identification. In addition, the sensitivity analysis is also used to study the effects of different value of S-y and the distance between pumping well and observation well on the influence time of S-y during the pumping. (c) 2006 Elsevier B.V. All rights reserved.
管管作品六首
(2007-03-15)
管管
Tunable fiber amplifier and laser
(2007-03-15)
Chi, Sien
;
Chen, Nan-Kuang
The present invention has a core and at least one cladding, where, by changing the temperature of the cladding, the material dispersion characteristic of the cladding is changed and a refractive index is varied to make fundamental-mode cutoff tunable as well; and the difference between dispersion slopes of core and cladding is crucial to the sharpness of the fundamental-mode cutoff.
Study on optimal growth conditions of a-plane GaN grown on r-plane sapphire by metal-organic chemical vapor deposition
(2007-03-15)
Ko, T. S.
;
Wang, T. C.
;
Gao, R. C.
;
Chen, H. G.
;
Huang, G. S.
Non-polar a-plane (1 1 (2) over bar 0) GaN thin films were grown on r-plane (1 (1) over bar 0 2) sapphire substrates by metal-organic chemical vapor deposition. In order to obtain a-plane GaN films with better crystal quality and surface morphology, detailed comparisons between different growth conditions were investigated. The results showed that high-temperature and low-pressure conditions facilitating two-dimensional growth could lead to a fully coalesced a-plane GaN layer with a very smooth surface. The best mean roughness of the surface morphology was 10.5 angstrom. Various thickness values of AlN nucleation layers and the V/III ratios for growth of the a-plane GaN bulk were also studied to determine the best condition for obtaining a smooth surface morphology of the a-plane GaN layer. (c) 2007 Elsevier B.V. All rights reserved.
Design of low-temperature CMOS-process compatible membrane fabricated with sacrificial aluminum layer for thermally isolated applications
(2007-03-15)
Chang, Kow-Ming
;
Lin, Ren-Jie
;
Deng, I-Chung
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In the surface micromachining technique, residual stress and sticking effect play an important role in determining whether a microstructure is suspended or collapse during a release process. In this paper, we propose a simpler method for making suspended membranes for thermally isolated application by using cheap processing steps and compatible with CMOS-process; also, there are some simulations done to predict stiction as function of the anchor profile. It is demonstrated by fabricating the test structures of CMOS-process compatible surface micromachined bolometer using aluminum sacrificial layer with high yield and high throughput. The aluminum sacrificial layer provides some benefits including rapid wet-etching and high wet-etching selectivity with respect to dielectric materials. The residual stress and gravity of the microstructures are evaluated with structural simulations, and the sticking effect can be alleviated by an appropriate structure design and a release process. Once the residual stress is known, we can successfully use Coventorware simulations to predict a suspended membrane by controlling the anchor profile which contains sidewall conformal factor and sidewall angle. The simulation results are in good agreement with the experiments. (c) 2006 Elsevier B.V. All rights reserved.
Synthesis and characterization of a vinyl-terminated benzoxazine monomer and its blends with poly(ethylene oxide)
(2007-03-15)
Huang, Jieh-Ming
;
Kuo, Shiao-Wei
;
Lee, Yuan-Jyh
;
Chang, Feng-Chiih
;
應用化學系
A vinyl-terminated benzoxazine (VB-a), which could be polymerized through ring-opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB-a monomer Was then subjected to blending with poly(ethylene oxide) (PEO), followed by thermal curing, to form poly(VB-a)/PEO blends. The specific interactions, miscibility, morphology, and thermal properties of these blends were investigated with Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). Before curing, we found that PEO was miscible with VB-a, as evidenced by the existence of a single composition-dependent glass transition temperature (T-g) for each composition. The FTIR spectra revealed the presence of hydrogen-bonding interactions between the hydroxyl groups of poly(VB-a) and the ether groups of PEO. Indeed, the ring-opening reaction and subsequent polymerization of the benzoxazine were facilitated significantly by the presence of PEO. After curing, DMA results indicated that the 50/50 poly(VB-a)/PEO blend exhibited two values of T-g: one broad peak appeared in the lower temperature region, whereas the other (at ca. 327 degrees C, in the higher temperature region) was higher than that of pristine poly (VB-a) (301 degrees C). The presence of two glass transitions in the blend suggested that this blend system was only partially miscible. Moreover, SEM micrographs indicated that the poly(VB-a)/PEO blends were heterogeneous. The volume fraction of PEO in the blends had a strong effect on the morphology. (c) 2007 Wiley Periodicals, lnc.
分離基態模截止可調式光纖放大器與雷射
(2007-03-16)
祁甡
;
陳南光
一種使用分離式基態模截止的可調式光纖放大器與雷射,其包含至少一光纖,而該光纖係分別具有一輸入端及一輸出端;以及至少一可間隔地分布於該光纖上以產生基態模截止波長(fundamental-mode cutoff wavelength)之濾波器,藉以形成一光纖放大器;另可於該光纖上設置至少一組共振腔藉以形成一雷射。藉此,可使本發明利用分離式基態模截止(discrete fundamental-mode cutoff)的方法來抑制摻鉺光纖在C頻帶的增益,使得較短波長的S頻帶能夠獲得足夠的光增益使信號放大。
主動式可調變電流之薄膜電晶體結構
(2007-03-16)
林彥仲
;
黃建智
;
楊佳峰
;
王俊雄
;
謝漢萍
本發明係為一主動式可調變電流之薄膜電晶體電路結構,特別是應用在主動式發光元件與其顯示陣列面板的畫素電路。本發明結構包括電流源、資料線、掃描線、直流電壓訊號線、複數儲存電容、複數開關電晶體與一驅動電晶體。其中複數儲存電容形成串聯結構,其功能為畫素電路由開啓期間轉為關閉期間時,其中一儲存電容因負回授效應而使得該等儲存電容間的節點的電位下降,進而使得流經發光元件之電流下降,以實現電流調變功能。複數開關電晶體功能為開關功能,以作為控制該電流源之電流方向。
Impacts of a polycrystalline-silicon buffer layer on the performance and reliability of strained n-channel metal-oxide-semiconductor field-effect transistors with SiN capping
(2007-03-19)
Lu, Ching-Sen
;
Lin, Horng-Chih
;
Huang, Jian-Ming
;
Lee, Yao-Jen
;
電子工程學系及電子研究所
Characteristics of n-channel metal-oxide-semiconductor field-effect transistors with SiN capping were investigated in this work. Although the SiN capping could dramatically enhance the carrier mobility and thus the device drive current, the resistance to hot-carrier degradation is compromised as well, owing to the large amount of hydrogen contained in the SiN layer which may diffuse into the channel region during the process. To eliminate this shortcoming, the insertion of an ultrathin (10 nm) polycrystalline-silicon buffer layer between the gate and the SiN capping was proposed and demonstrated to restore the hot-carrier reliability of the devices without compromising the current enhancement due to the SiN capping. (c) 2007 American Institute of Physics.
A pyroelectric infrared biometric system for real-time walker recognition by use of a maximum likelihood principal components estimation (MLPCE) method
(2007-03-19)
Fang, Jian-Shuen
;
Hao, Qi
;
Brady, David J.
;
Guenther, Bob D.
;
Hsu, Ken Y.
This paper presents a novel biometric system for real-time walker recognition using a pyroelectric infrared sensor, a Fresnel lens array and signal processing based on the linear regression of sensor signal spectra. In the model training stage, the maximum likelihood principal components estimation ( MLPCE) method is utilized to obtain the regression vector for each registered human subject. Receiver operating characteristic ( ROC) curves are also investigated to select a suitable threshold for maximizing subject recognition rate. The experimental results demonstrate the effectiveness of the proposed pyroelectric sensor system in recognizing registered subjects and rejecting unknown subjects. (c) 2007 Optical Society of America.
Heteroepitaxial growth of sixfold symmetric osmium on Si (111) and Si (100)
(2007-03-19)
Peng, Tai-Yen
;
Lo, C. K.
;
Yao, Y. D.
;
Chen, San-Yuan
;
材料科學與工程學系
Growing sixfold symmetric osmium (Os) epitaxial films with suitable buffer layers was developed. Using a Cu buffer layer, the lattice mismatch between Os (0002) and Si (100) was significantly reduced from > 30% to similar to 7% to grow Os films with twin relationships and weak sixfold symmetries. On the other hand, the Cu/Au buffer layer was selected to form a fcc (111) surface mesh on H-Si (111)-1x1, and therefore sixfold symmetric Os films were grown due to the lower lattice mismatch. Such growth properties may be applied in the high density magnetic random access memory manufacturing processes to connect the magnetic tunnel junction growth and Cu metal line directly. (c) 2007 American Institute of Physics.
Nonvolatile polycrystalline silicon thin-film-transistor memory with oxide/nitride/oxide stack gate dielectrics and nanowire channels
(2007-03-19)
Chen, Shih-Ching
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Wu, Yung-Chun
;
Yeh, Ping-Hung
In this work, the authors study a polycrystalline silicon thin-film transistor (poly-Si TFT) with oxide/nitride/oxide (ONO) stack gate dielectrics and multiple nanowire channels for the applications of both nonvolatile silicon-oxide-nitride-oxide-silicon (SONOS) memory and switch transistor. The proposed device named as nanowire SONOS-TFT has superior electrical characteristics of a transistor such as on/off current ratio, threshold voltage (V-th), and subthreshold slope due to the good gate control ability originated from fringing electrical field effects. Moreover, the proposed device under adequate operation scheme can exhibit high program/erase efficiency and good retention time characteristics at high temperature. (c) 2007 American Institute of Physics.
Generation of supercontinuum bottle beam using an axicon
(2007-03-19)
Lin, Ja-Hon
;
Wei, Ming-Dar
;
Liang, Hui-Hung
;
Lin, Kuei-Huei
;
Hsieh, Wen-Feng
A supercontinuum bottle beam was successfully produced by focusing a supercontinuum laser beam after passing through an axicon. The supercontinuum radiation was generated from a microstructured fiber pumped by a self-kerr-lensmode-locked femtosecond Ti: sapphire laser. The cross-section intensity distributions of the generated bottle were recorded by a beam profiler. Using the line filters to select different central wavelengths, the different colors of bottle beams show slightly different bottle ranges and diameters due to the dispersion of axicon and focusing lens. The results consist with the theoretical prediction using the Fresnel-Kirchhoff's formula in considering an incident Gaussian beam. (c) 2007 Optical Society of America.
Time-domain and spectral-domain investigation of inflection-point slow-light modes in photonic crystal coupled waveguides
(2007-03-19)
Huang, Shih-Chieh
;
Kato, Masao
;
Kuramochi, Eiichi
;
Lee, Chien-Ping
;
Notomi, Masaya
We report on spectral-domain and time-domain measurements and numerical calculations of group velocities in a photonic crystal coupled waveguide, where the unique guided mode band structure has a flat band region within the photonic band gap allowing for slow light observation. The spectral dependence of group velocity, which is measured by interference method, indicates the existence of slow light modes around the inflection point of the unique flat band, rather than at the band edge. Time-domain observation of optical pulses propagating along two-dimension slab photonic crystal coupled waveguides is also demonstrated by using a high speed oscilloscope. By adjusting the wavelength of the input pulses toward the flat band of the coupled defect modes, an increasing duration time between reference and output pulses are clearly observed. An extremely small group velocity of 0.017c is thus obtained. Calculated group velocities show good agreement with our measured results. (c) 2007 Optical Society of America.