Browsing by Issue Date, starting with "2007-09-08"

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Protein subcellular localization prediction based on compartment-specific features and structure conservation
(2007-09-08)
Su, Emily Chia-Yu
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Chiu, Hua-Sheng
;
Lo, Allan
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Hwang, Jenn-Kang
;
Sung, Ting-Yi
Background: Protein subcellular localization is crucial for genome annotation, protein function prediction, and drug discovery. Determination of subcellular localization using experimental approaches is time-consuming; thus, computational approaches become highly desirable. Extensive studies of localization prediction have led to the development of several methods including composition-based and homology-based methods. However, their performance might be significantly degraded if homologous sequences are not detected. Moreover, methods that integrate various features could suffer from the problem of low coverage in high-throughput proteomic analyses due to the lack of information to characterize unknown proteins. Results: We propose a hybrid prediction method for Gram-negative bacteria that combines a one-versus-one support vector machines ( SVM) model and a structural homology approach. The SVM model comprises a number of binary classifiers, in which biological features derived from Gram-negative bacteria translocation pathways are incorporated. In the structural homology approach, we employ secondary structure alignment for structural similarity comparison and assign the known localization of the top-ranked protein as the predicted localization of a query protein. The hybrid method achieves overall accuracy of 93.7% and 93.2% using ten-fold cross-validation on the benchmark data sets. In the assessment of the evaluation data sets, our method also attains accurate prediction accuracy of 84.0%, especially when testing on sequences with a low level of homology to the training data. A three-way data split procedure is also incorporated to prevent overestimation of the predictive performance. In addition, we show that the prediction accuracy should be approximately 85% for non-redundant data sets of sequence identity less than 30%. Conclusion: Our results demonstrate that biological features derived from Gram-negative bacteria translocation pathways yield a significant improvement. The biological features are interpretable and can be applied in advanced analyses and experimental designs. Moreover, the overall accuracy of combining the structural homology approach is further improved, which suggests that structural conservation could be a useful indicator for inferring localization in addition to sequence homology. The proposed method can be used in large-scale analyses of proteomes.
Computing wave functions of nonlinear Schrodinger equations: A time-independent approach
(2007-09-10)
Chang, S.-L.
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Chien, C.-S.
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Jeng, B.-W.
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應用數學系
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Department of Applied Mathematics
We present a novel algorithm for computing the ground-state and excited-state solutions of M-coupled nonlinear Schrodinger equations (MCNLS). First we transform the MCNLS to the stationary state ones by using separation of variables. The energy level of a quantum particle governed by the Schrodinger eigenvalue problem (SEP) is used as an initial guess to computing their counterpart of a nonlinear Schrodinger equation (NLS). We discretize the system via centered difference approximations. A predictor-corrector continuation method is exploited as an iterative method to trace solution curves and surfaces of the MCNLS, where the chemical potentials are treated as continuation parameters. The wave functions can be easily obtained whenever the solution manifolds are numerically traced. The proposed algorithm has the advantage that it is unnecessary to discretize or integrate the partial derivatives of wave functions. Moreover, the wave functions can be computed for any time scale. Numerical results on the ground-state and excited-state solutions are reported, where the physical properties of the system such as isotropic and nonisotropic trapping potentials, mass conservation constraints, and strong and weak repulsive interactions are considered in our numerical experiments. (C) 2007 Elsevier Inc. All rights reserved.
White p-i-n organic light-emitting devices with high power efficiency and stable color
(2007-09-10)
Ho, Meng-Huan
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Hsu, Shih-Feng
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Ma, Jia-Wei
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Hwang, Shiao-Wen
;
Yeh, Pu-Cheng
Highly efficient p-i-n two-component white organic light-emitting devices have been fabricated with a thin dual emission layer system comprised of one codeposited emitting layer with blue and yellow dyes and one blue emitting layer, which gives rise to a balance white emission. The p-i-n white device achieved an electroluminescence efficiency of 10 cd/A and a power efficiency of 9.3 lm/W at 1000 cd/m(2) and a low voltage of 3.4 V with a Commission Internationale de l'Eclairage coordinates of (0.32, 0.43). The electroluminescent color of this p-i-n white organic light-emitting diode device has been shown to be immune to drive current density variations.
Acoustic and optical phonon assisted formation of biexcitons
(2007-09-10)
Pan, Ching-Ju
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Lin, Kuo-Feng
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Hsieh, Wen-Feng
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光電工程學系
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Department of Photonics
Efficient exciton relaxation is required for bounding two cooled excitons to form biexciton. Acoustic and optical phonon scatterings playing key roles in exciton relaxation are responsible for formation of biexcitons at various temperatures. Using ZnO powders, the authors observed a sublinear dependence on excitation power at low temperature, in which the relaxation process involves only emission of acoustic phonons due to the excitons having kinetic energy lower than those of the optical phonons. However, the exponent comes near theoretical value of 2 for participation of optical phonons when the exciton kinetic energy approaches to the energy of the lowest optical phonon.
Wide-ratio broadband SiGe HBT regenerative frequency divider enhanced by differential TIA load
(2007-09-13)
Wei, H.-J.
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Meng, C.
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Chang, Y.-W.
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電信工程研究所
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Institute of Communications Engineering
Well-aligned ternary Cd1-xZnxS nanowire Arrays and their composition-dependent field emission properties
(2007-09-13)
Lin, Yi-Feng
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Hsu, Yung-Jung
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Lu, Shih-Yuan
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Chen, Kuan-Tsung
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Tseng, Tseung-Yuen
Well-aligned plain CdS and ternary Cd1-xZnxS nanowire arrays were successfully fabricated via a noncatalytic and template-free metal-organic chemical vapor deposition process. The nanowires were grown on a 1 mu m thick buffer layer formed in situ on the surface of silicon substrates. These nanowires were 20-40 nm in diameter and 500-900 nm in length. High-resolution transmission electron microscopy analyses revealed that the nanowires were single-cry stalline and grew along the [0001] direction of the hexagonal crystalline phase. The photoluminescence characterizations showed near band edge emissions at 535, 498, and 473 nm for the US nanowire arrays and Cd1-xZnxS nanowire arrays with x values of 0.21 and 0.44, respectively, demonstrating clear color tunability achieved with the composition adjustment of the alloy nanowires. The same morphology. and single-crystallinity of these three nanowire arrays enabled investigation of the composition-dependent field emission characteristics of the nanowire arrays for the first time, excluding interferences originating from morphology and crystallinity related factors. The plain CdS nanowire arrays exhibited better field emission properties, a lower turn-on field, and a higher field enhancement factor than the ternary Cd1-xZnxS nanowire arrays, for which the lower resistivity of the CdS nanowires may have played an important role. An important parameter, the absolute field enhancement factor (beta(0)), to more intrinsically quantify the field emission performance of the plain US and ternary Cd1-xZnxS nanowires arrays was also studied. The values of beta(0) decreased with increasing Zn content in the ternary products. The high beta(0) values of the US based nanowire arrays, comparable to that of carbon nanotubes grown on silicon wafers, made these nanowire arrays a promising candidate material for high-performance field emitting devices.
A Method For Predicting Inductance And Self-Resonant Frequency Of A Spiral Inductor
(2007-09-13)
Chen, Chien-Chang
;
Cheng, Yu-Ting
In this invention, a closed-form integral model for on-chip freely suspended rectangular spiral inductor is presented. The model of this invention bases on the Kramers-Kronig relations, field theory, and solid state physics to characterize a spiral inductor which RFIC designers could easily have the optimal design utilizing this analytical method. Meanwhile, this model can provide satisfactory prediction to the inductance and self-resonant frequency of the spiral inductor without complicated geometry analysis. Furthermore, unlike conventional formulations only based on circuit parameters, this model could safely predict the inductance and the self-resonant frequency when altering the material (excluding ferromagnetic materials) of a spiral inductor.
High strength and high toughness alloy with low density and the method of making
(2007-09-13)
Liu, Tzeng-Feng
;
Lee, Jian-Wei
The present invention relates to a high strength and high toughness alloy with a low density and the method of making thereof. The alloy essentially comprises 15 to 33 wt % of manganese, 6 to 10 wt % of aluminum, 0.6 to 1.2 wt % of carbon, 0.1 to 1.0 wt % of silicon, and the balance of iron. The alloy has excellent properties of a density of 6.6 to 6.9 g/cm3, an elongation of 25 to 70%, and a tensile strength of 100 to 190 ksi. In particularly, and the alloy is useful for golf club heads with excellent properties. Further, the use of the alloy reduces pits and defects generated during the electroplating process of the heads. Therefore, the defect rate of the product is remarkably decreased so that the cost is reduced.
Dynamics of the F-2+CH3SCH3 reaction: A molecule-molecule reaction without entrance barrier
(2007-09-14)
Lu, Yu-Ju
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Lee, Lance
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Pan, Jun-Wei
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Witek, Henryk A.
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Lin, Jim J.
The F-2+CH3SCH3 reaction was studied with crossed molecular beam techniques and high level ab initio calculations. Significant reactivity was observed even at low collision energies, consistent with the negligible barrier height obtained from the ab initio calculations. All experimental findings are consistent with a weakly bound reaction intermediate of F-F-S(CH3)(2) structure, which possesses a special type of three-center four-electron bonding. Analogous intermediates can also explain the reactions of F-2 with CH3SH and CH3SSCH3.
Efficient algorithms for regular expression constrained sequence alignment
(2007-09-15)
Chung, Yun-Sheng
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Lu, Chin Lung
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Tang, Chuan Yi
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生物科技學系
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Department of Biological Science and Technology
Imposing constraints is an effective means to incorporate biological knowledge into alignment procedures. As in the PROSITE database, functional sites of proteins can be effectively described as regular expressions. In an alignment of protein sequences it is natural to expect that functional motifs should be aligned together. Due to this motivation, Arslan introduced the regular expression constrained sequence alignment problem and proposed an algorithm which, if implemented naively, can take time and space up to O(vertical bar Sigma vertical bar V-2 vertical bar vertical bar(4)n(2)) and O(vertical bar Sigma vertical bar(2)vertical bar V vertical bar(4)n), respectively, where Sigma is the alphabet, n is the sequence length, and V is the set of states in an automaton equivalent to the input regular expression. In this paper we propose a more efficient algorithm solving this problem which takes O(vertical bar V vertical bar(3)n(2)) time and O(vertical bar V vertical bar(2n)) space in the worst case. If vertical bar V vertical bar = O(log n) we propose another algorithm with time complexity O(vertical bar V vertical bar(2)log vertical bar V vertical bar n(2)). The time complexity of our algorithms is independent of Sigma, which is desirable in protein applications where the formulation of this problem originates; a factor of vertical bar Sigma vertical bar(2) = 400 in the time complexity of the previously proposed algorithm would significantly affect the efficiency in practice. (c) 2007 Elsevier B.V All rights reserved.
Optical method for measuring the azimuthal anchoring strength of liquid crystals using pitch values determined in imperfect samples
(2007-09-15)
Tang, Tsung-Ta
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Wu, Hsin-Ying
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Lin, Chia-Jen
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Pan, Ru-Pin
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電子物理學系
An improved Grandjean-Cano wedge method for measuring the pitch of a chiral nematic liquid crystal is demonstrated. This method is easy to implement and can yield results of high accuracy when it is used for measuring the liquid crystal surface anchoring strength.(C) 2007 American Institute of Physics.
Methods of achieving linear index-change response for narrow-band fiber Bragg grating sequential writing
(2007-09-15)
Hsu, Kuei-Chu
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Sheu, Lih-Gen
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Hsiang, Wei-Wei
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Lai, Yinchieh
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光電工程學系
This investigation elucidates the refractive index-change response of the photosensitive optical fiber to exposed UV flux. The nonlinear U-V photosensitivity deforms the index profile of FBGs on the tail edges where the writing UV flux is low. Pre-UV treatment eliminates the nonlinear index-change response and ensures the linearity of the response of subsequent grating writing. A new method that involves interference between two unequal beams in a single writing scan is proposed and demonstrated to be able to improve the index profile and the spectral response of fabricated FBGs. The procedure is stable for writing weak fiber Bragg gratings with pre-designed index profiles. (c) 2007 Elsevier B.V. All rights reserved.
聲源能量分佈可視化系統及其方法
(2007-09-16)
白明憲
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林家鴻
;
甯攸威
本發明提供一種聲源能量分佈可視化系統及其方法,其係在求得波傳遞矩陣與窗口矩陣後,透過將波傳遞矩陣進行反逆運算,以及將反逆運算結果與窗口矩陣作相乘運算,把相乘運算結果由頻率域轉換成時間域後,建立起聲源能量分佈重建器,而在進一步利用陣列式麥克風接收聲源訊號,且使用多通道擷取裝置將聲源訊號轉換成數位聲源訊號後,讓數位聲源訊號與聲源能量分佈重建器作旋積運算,而得到一可視化之聲源能量分佈。因此,本發明提供一種聲源能量分佈可視化系統及其方法,其可獲得近場及遠場之穩態與非穩態聲源的能量分佈情形,或是任一頻帶內的聲源能量分佈情況。
低密度高強度高韌性合金材料及其製法
(2007-09-16)
劉增豐
;
李堅瑋
本發明係關於一種低密度、高强度、高韌性之合金材料及其製法。該合金材料其主要包含15~33重量百分比之錳、6~10重量百分比之鋁、0.6~1.2重量百分比之碳、0.1~1.0重量百分比之矽及其餘比例以鐵為基材之合金材料,其具有6.6~6.9g/cm^3的密度、25~70%的延伸率或100~190ksi的抗拉强度等極佳的性質,故使得該合金材料可達到高强度、低密度、高延展性及優異表面性質之高爾夫桿頭設計目的,且該合金材料更可降低高爾夫桿頭在電鍍過程中所產生的孔蝕孔洞及缺陷的發生,因此大幅降低產品的不良率及成本。
在矽（110）基板上設有壓縮應變矽鍺通道之N型金氧半電晶體架構
(2007-09-16)
羅廣禮
;
簡昭欣
;
楊宗
本發明係提供一種在矽(110)基板上設有壓縮應變矽鍺通道之N型金氧半電晶體架構,其係包括一P^-型矽(110)基板、二離子植入區用於源極與汲極、一壓縮應變矽鍺通道層與一閘極結構,其中,在P^-型矽(110)基板上成長應變矽鍺電子通道層,以使得電子在【1-10】晶格方向上的傳導有效質量降低,提高電子在【1-10】方向上的傳導速度。因此,本發明係在矽(110)基板上可製作出高電子遷移率的N型金氧半電晶體。本發明所提出的N型金氧半電晶體還可以配合矽(110)基板上之高速P型金氧半電晶體以形成高性能之互補式金氧半電晶體。
一種預測雙埠晶片懸浮螺旋式電感之感值與共振頻率的方法
(2007-09-16)
陳健章
;
鄭裕庭
本發明關於一種預測懸浮電感之共振頻率及其感値的方法。本發明係根據Kramers-Kronig relations、場論以及固態物理所推導而成之物理公式,因此RFIC的設計工程師可輕易地藉由適當的選擇與改變本方法當中之物理參數,以達到電感最佳化設計之目的。更進一步地,不同於其他方法缺乏材料之物理特性的缺點,若設計工程師必須更改電感之材料(鐵磁性材料除外)時,本發明方法亦可以成功預測其感値與共振頻率。
Anisotropy of light extraction from two-dimensional photonic crystal light-emitting diodes
(2007-09-17)
Lai, Chun-Feng
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Kuo, H. C.
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Chao, C. H.
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Hsueh, H. T.
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Wang, J.-F. T.
Anisotropic light extraction of photonic crystal (PhC) light-emitting diodes in the azimuthal direction has been investigated with an annular structure of triangular PhC lattice. The optical images of the photoluminescence light extraction are obtained with laser excitation. For increasing lattice constant, sixfold symmetric patterns with varying numbers of petals in multiples of six are observed and analyzed. A map of the anisotropy for various lattice constants and numerical apertures is constructed. Several features of light propagations associated with the PhC are observed including the focusing and collimating behaviors.(c) 2007 American Institute of Physics.
Interband transitions in sol-gel-derived ZrO2 films under different calcination conditions
(2007-09-18)
Chang, Sue-min
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Doong, Ruey-an
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環境工程研究所
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Institute of Environmental Engineering
Different types of interband transitions as well as the microstructures and O/Zr ratios in sol-gel-derived ZrO2 films calcined at elevated temperatures in air or N-2 were systematically examined to clarify the formation of different band structures in the structural ZrO2 films. Optical absorptions indicate that the structural ZrO2 films all contain direct-band transitions, while the occurrence of indirect-band and band-tail transitions, depends on O/Zr ratios. Band tails mainly result from imperfect structures in the grain boundaries and appear in the ZrO2 films with O/Zr >= 2. When the ZrO2 films are non-stoichiometric (O/Zr < 2), indirect-band transitions occur due to the folded bands caused by lattice oxygen vacancies. Monoclinic ZrO2 has two direct-band transitions with bandgaps of 5.02-5.08 and 5.83-6.01 eV. The valence-band XPS spectra indicate that an additional occupied sub-band is located above its valence band. Indirect bandgaps in the monoclinic ZrO2 films are in the range of 5.00-5.10 eV. Amorphous ZrO2 films exhibit indirect-band transitions with bandgaps of 5.01-5.47 eV followed by direct-band transitions with bandgaps of 5.90-6.12 eV. In addition, tetragonal ZrO2 contains direct bandgaps of 5.32-5.74 eV and indirect bandgaps of 4.72-5.40 eV. Size-dependent bandgaps are observed in the sol-gel-derived ZrO2 films calcined in air, while the exponential dependence of bandgaps on O/Zr ratios is obtained in the ZrO2 films calcined in N-2. The discrepancy is primarily due to different fates of oxygen vacancies resulting from different calcination atmospheres.
Controlled pulsatile drug release from a ferrogel by a high-frequency magnetic field
(2007-09-18)
Hu, Shang-Hsiu
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Liu, Ting-Yu
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Liu, Dean-Mo
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Chen, San-Yuan
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材料科學與工程學系
Loudspeaker system having sensorless bass compensation
(2007-09-20)
Bai, Ming-Shian
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Lee, Chih-Chung
;
Lin, Chien-Liang
The present invention compensates bass frequency for a loudspeaker without using any sensor. The strength and stability of the loudspeaker are enhanced and the working frequency is lowered too. Adaptive loudnesses for various spaces are set. And the parameter drift owing to long-term operation is restrained as well.