Browsing by Issue Date, starting with "2008-09-10"

Now showing 1 - 20 of 54669

Thermal fluctuation-induced tunneling conduction through metal nanowire contacts
(2008-09-10)
Lin, Yong-Han
;
Chiu, Shao-Pin
;
Lin, Juhn-Jong
;
電子物理學系
;
物理研究所
The temperature behavior of how electrons propagate through an insulating electronic contact formed at the interface between a submicron Cr/Au electrode and a metallic RuO(2) nanowire (NW) has been studied between 300 and 1 K. The NWs are typically of similar to 70 nm in diameter and a few microns long. The submicron electrodes were fabricated by the standard electron-beam lithography technique. By employing the two-probe method, the electronic contact resistances, R(c)(T), have been determined. We found that, in general, Rc increases rapidly with decreasing temperature but eventually saturates at liquid-helium temperatures. Such a temperature behavior can be well described by a thermal fluctuation-induced tunneling (FIT) conduction process which considers the crossover feature from thermal activation conduction at high temperatures to simple elastic tunneling conduction at low temperatures. The wide applicability of this FIT model has further been established by employing metallic IrO(2) and Sn-doped In(2)O(3-x) NWs. This work demonstrates that the underlying physics for the charge transport properties of an insulating electronic contact can be well understood.
Potential energy surfaces for the lowest excited states of the nitrogen-vacancy point defects in diamonds: A quantum chemical study
(2008-09-10)
Zyubin, A. S.
;
Mebel, A. M.
;
Chang, H. C.
;
Lin, S. H.
;
應用化學系
Quantum chemical calculations of geometry relaxation in lowest excited states of neutral (NV(O)) and negatively charged (NV) nitrogen-vacancy point defects in diamond have been performed employing the CASSCF method with a finite NC(19)H(28) model cluster. Vibrations activated by the electronic transitions are determined by comparing calculated atomic displacements in the excited states with normal mode vectors, and the activated frequencies are evaluated as similar to 600 cm (1). The barrier for N migration through the vacancy in NV is estimated at the TD-B3LYP level and no significant decrease of this barrier (similar to 5 eV in the ground state) is found due to electronic excitations. (c) 2008 Elsevier B. V. All rights reserved.
低音補強模組之微型喇叭
(2008-09-11)
白明憲
;
廖哲緯
本發明係一種低音補强模組之微型喇叭,適用於手提式裝置,如手機、掌上型遊戲機、PDA者,其係由音箱、凹槽及管路所組成。在音箱的側緣設二開口分別與連接凹槽及管路連接。凹槽內具有單體喇叭,管路係低音反射管。管路之音量與管路的面積及長度有關,與形狀無關,因此本發明可依據不同之形狀需求(如不同之手機造型需求)設計出不同之低音反射管以符合所需,藉由低音反射管增强微型喇叭的低音響應頻率,並不會因為手機容積變小,使低音響應頻率之效果變差。
CYCLIC COMPARISON METHOD FOR LOW-DENSITY PARITY-CHECK DECODER
(2008-09-11)
HUNG, Jui-Hui
;
Hung, Jui-Hung
;
Chen, Sau-Gee
The present invention discloses a cyclic comparison method for an LDPC decoder, which applies to the comparators used in an LDPC decoder. According to the cyclic comparison algorithm of the present invention, the nth element of the input k elements, wherein n=1, . . . , k, is sequentially removed by the corresponding comparator to obtain k first series. Next, pairs of two elements selected from the k elements are used to form k second series. The preceding step is repeated k×log2(k−1) times to obtain k completion series. Either of one first series and one completion series contains (k−1) elements. The first series are compared with the completion series to determine whether they are identical. If they are identical, the process stops. If they are not identical, the abovementioned step is repeated to obtain new completion series. The cyclic comparison method of the present invention needs only k×log2(k−1) comparisons to obtain completion series. Thus, the present invention can reduce the number of basic operations and can apply to any input number. Further, the present invention can be easily programmed and can achieve the optimal solution.
High performance poly-Si TFTs fabricated by continuous-wave laser annealing of metal-induced lateral crystallised silicon films
(2008-09-11)
Chang, C. -P.
;
Wu, Y. S.
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In this process, amorphous silicon was first transformed to polycrystalline silicon (poly-Si) using a metal-induced lateral crystallisation (MILC) process, followed by annealing with a continuous-wave laser lateral (lambda similar to 532 nm) crystallisation (CLC) with an output power of 3.8 W. MILC-CLC-TFT performed far superior to MILC-TFT. The mobility of the MILC-CLC-TFT was 293 cm(2)/Vs, which was much higher than that of MILC TFTs (54.8 cm(2)/Vs). In addition, MILC-CLC TFTs showed better device uniformity and reliability.
Fabrication and characterization of eutectic gold-silicon (Au-Si) nanowires
(2008-09-12)
Lin, Jin-Shyong
;
Chen, Chien-Chon
;
Diau, Eric Wei-Guang
;
Liu, Tzeng-Feng
;
材料科學與工程學系
Hypoeutectic, eutectic and hypereutectic gold-silicon (Au-Si) alloys were synthesized using vacuum smelting. When Au and Si were smelted in a vacuum chamber near 1100 degrees C, Si-(g), Si-2(g), Si-3(g), SiO2(g), Au-(g), SiO2(s) and Au2O3(s) were formed rapidly; the quantities of Au and Si lost were estimated from thermodynamic formulas. The nano- and microstructures of the Au-Si,eutectic compound were characterized with a SEM and a TEM, which showed a discontinuous phase of Si dispersed and mounted within a matrix phase of Au. Cracks that formed about the Au-Si interface made the Au-Si eutectic brittle. From an Au-Si alloy of superior quality as a bulk material, eutectic nanowires of average diameter 60 nm were fabricated after the alloy was melted and injected into an anodic aluminum-oxide (AAO) template. (C) 2008 Elsevier B.V. All rights reserved.
Direct spectral evidence of single-axis rotation and ortho-hydrogen-assisted nuclear spin conversion of CH(3)F in solid para-hydrogen
(2008-09-14)
Lee, Yuan-Pern
;
Wu, Yu-Jong
;
Hougen, Jon T.
;
應用化學系
;
應用化學系分子科學碩博班
Observation of two weak absorption lines from the E (K=1) level and one intense feature from A (K=0) for degenerate modes v(4) and v(6) of CH(3)F provides direct spectral evidence that CH(3)F isolated in p-H(2) rotates about only its symmetry axis, and not about the other two axes. An interaction between A and E vibrational levels caused by the partially hindered spinning rotation is proposed. Conversion of nuclear spin between A and E components of CH(3)F is rapid when p-H(2) contains some o-H(2), but becomes slow when the proportion of o-H(2) is much decreased. (c) 2008 American Institute of Physics.
管管作品二十五首
(2008-09-15)
管管
New approach to fabricate an extremely super-amphiphobic surface based on fluorinated silica nanoparticles
(2008-09-15)
Sheen, Yuung-Ching
;
Huang, Yuan-Chang
;
Liao, Chun-Syong
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Chou, Hisn-Yi
;
Chang, Feng-Chih
Superoleophobic surfaces possessing static contact angles greater than 140 degrees with organic liquids are extremely rare. A simple approach has been developed to fabricate an extremely superamphiphobic coating material based on fluorinated silica nanoparticles resulting contact angles of water and diiodomethane at 167.5 degrees and 158.6 degrees, respectively. The contact angle of diiodomethane at 158.6 degrees is substantially higher than the highest literature reported value we know of at 110 degrees. In addition, this developed film also possesses extremely high contact angles with other organic liquids such as soybean oil (146.6 degrees), decahysronaphthalene (142.5 degrees), diesel fuel (140.4 degrees), and xylene (140.5 degrees). This developed superamphiphobic organic-inorganic hybrid film possesses unique liquid repellency for both water and organic liquids that can be used as functional coatings on numerous substrates by a simple coating process. (C) 2008 Wiley Periodicals, Inc.
管管作品二十五首
(2008-09-15)
管管
管管作品二十五首
(2008-09-15)
管管
管管作品二十五首
(2008-09-15)
管管
管管作品二十五首
(2008-09-15)
管管
A simple approach toward low-dielectric polyimide nanocomposites: Blending the polyimide precursor with a fluorinated polyhedral oligomeric silsesquioxane
(2008-09-15)
Ye, Yun-Sheng
;
Yen, Ying-Chieh
;
Chen, Wen-Yi
;
Cheng, Chih-Chia
;
Chang, Feng-Chih
This article describes a new and simple method for preparing polyimide nanocomposites that have very low dielectric constants and good thermal properties: simply through blending the polyimide precursor with a fluorinated polyhedral oligomeric silsesquioxane derivative, octakis(dimethylsiloxyhexafluoropropyl) silsesquioxane (OF). The low polarizability of OF is compatible with polyimide matrices, such that it can improve the dispersion and free volume of the resulting composites. Together, the higher free volume and lower polarizability of OF are responsible for the lower dielectric constants of the PI-OF nanocomposites. This simple method for enhancing the properties of polyimides might have potential applicability in the electronics industry. (C) 2008 Wiley Periodicals, Inc.
Characteristics of GaN-based photonic crystal surface emitting lasers
(2008-09-15)
Lu, Tien-chang
;
Chen, Shih-Wei
;
Kao, Tsung-Ting
;
Liu, Tzu-Wei
;
光電工程學系
Characteristics of GaN-based photonic crystal surface emitting lasers (PCSELs) were investigated and analyzed. The GaN-based PCSEL emits a blue wavelength at 401.8 nm with a linewidth of 1.6 angstrom and shows a threshold energy density about 2.7 mJ/cm(2) under the optical pumping at room temperature. The lasing wavelength emitted from PCSELs with different lattice constants occurs at the calculated band edges showing different polarization angles due to the light diffracted in specific directions, corresponding exactly to Gamma, K, and M directions in the K-space. Furthermore, the PCSEL also shows a spontaneous emission coupling efficiency beta of about 5 X 10(-3) and a characteristic temperature of 148 K. (C) 2008 American Institute of Physics.
Vertically well-aligned epitaxial Ni(31)Si(12) nanowire arrays with excellent field emission properties
(2008-09-15)
Lee, Chung-Yang
;
Lu, Ming-Pei
;
Liao, Kao-Feng
;
Wu, Wen-Wei
;
Chen, Lih-Juann
Vertically well-aligned single crystal Ni(31)Si(12) nanowire (NW) arrays were epitaxially grown on Ni(31)Si(12) films preferentially formed on Ni foil substrates with a simple vapor phase deposition method in one step. The Ni(31)Si(12) NWs are several micrometers in length and 50-80 nm in diameter. The resistivities of the Ni(31)Si(12) NWs were measured to be 51 mu Omega cm by four-terminal electrical measurement. The NWs can carry very high currents and possess excellent field emission properties. The growth of vertically well-aligned Ni(31)Si(12) NW arrays shall lead to significant advantages in the fabrication of vertical Si nanodevices. (C) 2008 American Institute of Physics.
Coverage probability of prediction intervals for discrete random variables
(2008-09-15)
Wang, Hsiuying
;
統計學研究所
;
Institute of Statistics
Prediction interval is a widely used tool in industrial applications to predict the distribution of future observations. The exact minimum coverage probability and the average coverage probability of the conventional prediction interval for a discrete random variable have not been accurately derived in the literature. In this paper, procedures to compute the exact minimum confidence levels and the average confidence levels of the prediction intervals for a discrete random variable are proposed. These procedures are illustrated with examples and real data applications. Based on these procedures, modified prediction intervals with the minimum coverage probability or the average coverage probability close to the nominal level can be constructed. (c) 2008 Elsevier B.V. All rights reserved.
Pragmatical adaptive chaos control from a new double van der Pol system to a new double Duffing system
(2008-09-15)
Ge, Zheng-Ming
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Li, Shih-Chung
;
Li, Shih-Yu
;
Chang, Ching-Ming
;
機械工程學系
A new pragmatical adaptive control method for different chaotic systems is proposed. Traditional chaos control is limited to decrease chaos of one chaotic system. This method enlarges the effective scope of chaos control. We can control a chaotic system, e.g. a new chaotic double van der Pol system, to a given chaotic or regular system, e.g. a new chaotic double Duffing system or to a damped simple harmonic system. By a pragmatical theorem of asymptotical stability based on an assumption of equal probability of initial point, an adaptive control law is derived such that it can be proved strictly that the common zero solution of error dynamics and of parameter dynamics is asymptotically stable. Numerical simulations are given to show the effectiveness of the proposed scheme. (C) 2008 Elsevier Inc. All rights reserved.
Magnetic phase diagram of type-II superconductors: From high T-c to low T-c superconductors
(2008-09-15)
Li, D.
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Lin, P. J.
;
Rosenstein, B.
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電子物理學系
;
Department of Electrophysics
Phase diagram of both high temperature superconductors and low temperature superconductors are studied within the Ginzburg-Landau approach. Due to enhanced thermal fluctuation strength, disorder effects are relatively small in high T-c superconductors and consequently can be studied analytically. The vortex glass transition line is different and well separated from both the melting line and from the so-called second peak lines. On contrary, in low temperature superconductors, the disorder effect is dominant, as the thermal fluctuation strength is very small. Peak effect appears due to cross over of the collective pinning region to stronger pinning region. The location of the peak effect is obtained. The disorder and thermal fluctuation effects on structure phase transition are also studied. (C) 2008 Elsevier B.V. All rights reserved.
管管作品二十五首
(2008-09-15)
管管