Browsing by Issue Date, starting with "2008-09-02"

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Cu-metalized compound semiconductor device
(2008-09-02)
Chang
;
Edward Yi
;
Chang
;
Shang-Wen
;
Lee
The present invention is a compound semiconductor device characterized in that it is Cu-metalized to improved the reliability of the device and to greatly reduce the cost of production.
Ni(2+) doping DNA: a semiconducting biopolymer
(2008-09-03)
Jian, Peng-Chung Jang
;
Liu, Tzeng-Feng
;
Tsai, Chuan-Mei
;
Tsai, Ming-Shih
;
Chang, Chia-Ching
DNA is a one-dimensional nanowire in nature, and it may not be used in nanodevices due to its low conductivity. In order to improve the conducting property of DNA, divalent Ni(2+) are incorporated into the base pairs of DNA at pH >= 8.5 and nickel DNA (Ni-DNA) is formed. Conducting scanning probe microscopy (SPM) analysis reveals that the Ni-DNA is a semiconducting biopolymer and the Schottky barrier of Ni-DNA reduces to 2 eV. Meanwhile, electrochemical analysis by cyclic voltammetry and AC impedance shows that the conductance of Ni-DNA is better than that of native DNA by a factor of approximately 20-fold. UV spectroscopy and DNA base pair mismatch analyses show that the conducting mechanism of Ni-DNA is due to electrons hopping through the pi-pi stacking of DNA base pairs. This biomaterial is a designable one-dimensional semiconducting polymer for usage in nanodevices.
Ni2+ doping DNA: a semiconducting biopolymer
(2008-09-03)
Jian, Peng-Chung Jang
;
Liu, Tzeng-Feng
;
Tsai, Chuan-Mei
;
Tsai, Ming-Shih
;
Chang, Chia-Ching
DNA is a one-dimensional nanowire in nature, and it may not be used in nanodevices due to its low conductivity. In order to improve the conducting property of DNA, divalent Ni2+ are incorporated into the base pairs of DNA at pH >= 8.5 and nickel DNA (Ni-DNA) is formed. Conducting scanning probe microscopy (SPM) analysis reveals that the Ni-DNA is a semiconducting biopolymer and the Schottky barrier of Ni-DNA reduces to 2 eV. Meanwhile, electrochemical analysis by cyclic voltammetry and AC impedance shows that the conductance of Ni-DNA is better than that of native DNA by a factor of approximately 20-fold. UV spectroscopy and DNA base pair mismatch analyses show that the conducting mechanism of Ni-DNA is due to electrons hopping through the pi-pi stacking of DNA base pairs. This biomaterial is a designable one-dimensional semiconducting polymer for usage in nanodevices.
Miscibility and hydrogen-bonding behavior in organic/inorganic polymer hybrids containing octaphenol polyhedral oligomeric silsesquioxane
(2008-09-04)
Yen, Ying-Chieh
;
Kuo, Shiao-Wei
;
Huang, Chih-Feng
;
Chen, Jem-Kun
;
Chang, Feng-Chih
In this study, we Investigated the miscibility behavior and mechanism of interaction of poly(methyl mechacrylate) (PMMA), poly(vinyl pyrrolidone) PVP, and PMMA-co-PVP blends with octa(phenol)octasilsequioxane (OP-POSS). For the PMMA/OP-POSS binary blend, the value of the association constant (K(A) = 29) was smaller than that in the poly(vinyl phenol) (PVPh)/PMMA (K(A) = 37.4) and ethyl phenol (EPh)/PMMA (K(A) = 101) blend systems, implying that the phenol groups of the OP-POSS units in the PMMA/OP-POSS blends interacted to a lesser degree with the C=O groups of PMMA than they did in the other two systems. In addition, the ionic conductivity of a LiClO(4)/PMMA-co-PVP polymer electrolyte was increased after blending with OP-POSS.
交大e-News第032期
(2008-09-05)
Secretariat
;
國立交通大學秘書室
A random graph-based model to analyze packet interference between frequency hopping systems with an application to Bluetooth
(2008-09-05)
Naik, Kshirasagar
;
Wei, David S. L.
;
Su, Yu T.
;
Shiratori, N.
;
電信工程研究所
In this paper, we present a graph-based model for analyzing interference between two frequency hopping systems for wireless communication. Informally, frequency hopping means that successive packets are transmitted on different frequencies from a pseudo-random sequence. The frequency band occupied by a packet may be narrow or wide. Our model is based on the concept of probabilistic graphs, where a node represents a "channel" and an edge denotes the probability of interference between two packets belonging to two different channels. Two packets on two channels are said to be mutually interfering if the two packets overlap in time and are transmitted on the same frequency. Thus, from the viewpoint of probabilistic graphs, the expected number of nodes with at least one incident edge is a measure of packet interference in a collection of wireless channels. We apply this model of packet interference to a heterogeneous cluster of Bluetooth piconets, where a piconet could be either of 79-hop type or of 23-hop type. Though the 23-hop type has been phased out, we use it as an example in this paper. (C) 2008 Elsevier B.V. All rights reserved.
The linear 3-arboricity of Kn,n and Kn
(2008-09-06)
Fu, Hung-Lin
;
Huang, Kuo-Ching
;
Yen, Chih-Hung
;
應用數學系
;
Department of Applied Mathematics
A linear k-forest is a forest whose components are paths of length at most k. The linear k-arboricity of a graph G, denoted by la(k) (G), is the least number of linear k-forests needed to decompose G. In this paper, we completely determine lak (G) when G is a balanced complete bipartite graph K-n,K-n or a complete graph K-n, and k = 3. (C) 2007 Elsevier B.V. All rights reserved.
Improved air stability of n-channel organic thin-film transistors with surface modification on gate dielectrics
(2008-09-08)
Chen, Fang-Chung
;
Liao, Cheng-Hsiang
;
光電工程學系
;
顯示科技研究所
;
Department of Photonics
The air stability of n-channel organic thin film transistors based on N, N' -dioctyl-3,4,9,10-perylene tetracarboxylic diimide is improved when modifying the dielectric surfaces with polymer insulators. The hydrophobic nature of the polymer surface inhibits protonation of the siloxyl groups on the SiO(2) surface, leading to fewer SiO(-) groups that can behave as electron traps. Among the polymer insulators tested, the devices modified with hydroxyl-free polymers exhibited the best air stabilities. (c) 2008 American Institute of Physics.
Morphological, structural, and mechanical characterizations of InGaN thin films deposited by MOCVD
(2008-09-08)
Yang, Ping-Feng
;
Jian, Sheng-Rui
;
Lai, Yi-Shao
;
Yang, Chu-Shou
;
Chen, Rong-Sheng
Presented in this study are surface roughness, crystalline structure, and nanomechanical properties of InGaN thin films deposited under various growth temperatures, obtained by means of X-ray diffraction (XRD), atomic force microscopy (AFM), and nanoindentation techniques. The InGaN thin films with different In contents were deposited on sapphire substrates through a metal-organic chemical-vapor deposition (MOCVD) system. Changes in mechanical properties for InGaN thin films are discussed in conjunction with deposition temperature, surface morphology and crystalline structure. The XRD measurements showed that there was no phase separation of In as the In composition went from 25 at.% to 34 at.%. Moreover, both XRD and AFM showed larger grain and surface roughness in In0.25Ga0.75N thin films. Nanoindentation results indicate that hardness and Young's modulus both decreased as the indentation depth increased. The contact stress-strain relationships were also analyzed. (C) 2007 Elsevier B.V. All fights reserved.
Frequency dependence of negative differential capacitance in Schottky diodes with InAs quantum dots
(2008-09-08)
Lin, S. D.
;
Ilchenko, V. V.
;
Marin, V. V.
;
Panarin, K. Y.
;
Buyanin, A. A.
The frequency dependence of negative differential capacitance (NDC) in Schottky diodes with InAs quantum dots (QDs) is studied. The measured peak capacitances of NDC decay rapidly as the testing frequencies are higher than a few kilohertz. A kinetic model considering the testing signal is proposed and the capture rates of QDs are extracted. The simulation result is quantitatively consistent with the experimental data when the charging effect in QDs is included. (c) 2008 American Institute of Physics.
Formation mechanism of a nanotubular polyanilines prepared by an emulsion polymerization without organic solvent
(2008-09-09)
Hsieh, Bi-Zen
;
Chuang, Hung-Yi
;
Chao, Liang
;
Li, Yu-Jen
;
Huang, Ying-Jie
A nanotubular polyaniline (PANINT) was prepared from a simple emulsified polymerization method without oil solvent present. A mechanism of the formation of the nano-fibers/tubes was proposed to show that it started with the connecting arrangement of the neighboring anilinium micelles before and during polymerization, which resulted in the formation of the intermediate morphology of centipedes converting into rod-like nanofibers later. The obtained PANINTs displayed not only nanofibrous structure but owned an unusual dispersing behavior in toluene. SEM and TEM showed the dendrite-like networks of nanofibers connected and glued together by the free (not complexed to polyaniline backbone) n-dodecylbenzene sulfonic acid (DBSA) molecules. After removing the free DBSA by acetone, the clear/well-defined empty nanotubes can be seen from TEM in the magnified micrograph. The Atomic force microscopic (AFM) microgaphs demonstrated the cottage like surface morphology of the un-perturbed PANINTs and the morphology was converted to an anisotropic/oriented rods after rubbing on the wet/ cast PANINTs' dispersion of toluene before entire evaporation. (c) 2008 Published by Elsevier Ltd.
Brain nociceptive imaging in rats using F-18-fluorodeoxyglucose small-animal positron emission tomography
(2008-09-09)
Shih, Y. -Y. I.
;
Chiang, Y. -C.
;
Chen, J. -C.
;
Huang, C. -H.
;
Chen, Y. -Y.
Preclinical exploration of pain processing in the brain as well as evaluating pain-relief drugs in small animals embodies the potential biophysical effects in humans. However, it is difficult to measure nociception-related cerebral metabolic changes in vivo, especially in unanesthetized animals. The present study used F-18-fluorodeoxyglucose small-animal positron emission tomography to produce cerebral metabolic maps associated with formalin-induced nociception. Anesthesia was not applied during the uptake period so as to reduce possible confounding effects on pain processing in the brain. The formalin stimulation at the hind paw of rats resulted in significant metabolic increases in the bilateral cingulate cortex, motor cortex, primary somatosensory cortex, secondary somatosensory cortex, insular cortex, visual cortex, caudate putamen, hippocampus, periaqueductal gray, amygdala, thalamus, and hypothalamus. Among the measured areas, clear lateralization was only evident in the primary somatosensory cortex and hypothalamus. In addition, pretreatment with lidocaine (4 mg/kg, i.v.) and morphine (10 mg/kg, i.v.) significantly suppressed formalin-induced cerebral metabolic increases in these areas. The present protocol allowed identification of the brain areas involved in pain processing, and should be useful in further evaluations of the effects of new drugs and preclinical therapies for pain. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.
Self-assembled hollow nanocapsule from amphiphatic carboxymethyl-hexanoyl chitosan as drug carrier
(2008-09-09)
Liu, Kun-Ho
;
Chen, San-Yuan
;
Liu, Dean-Mo
;
Liu, Tse-Ying
;
材料科學與工程學系
A new type of amphiphilic chitosan, which was synthesized through the use of both hydrophilic carboxymethyl and hydrophobic hexanoyl substitutions, was employed to self-assemble into a hollow nanocapsule in an aqueous environment. Critical aggregation concentration (cac) and zeta potential were experimentally identified for the amphiphilic chitosan (CHC). Both experimental data suggested that the self-assembly behavior of the CHC is fundamentally determined as an interplay between the hydrophobic interaction and the variation of the zeta potential upon hexanoyl substitution, which further influenced the nanostructural evolution of the nanocapsules. Higher hexanoyl substitution promoted larger nanocapsules, ca. 200 nm in diameter, while a reduced zeta potential was correspondingly detected, and vice versa, forming smaller nanocapsules, ca. 20 nm in diameter. The self-assemble mechanism, together with the corresponding nanostructural stability, of this unique CHC nanocapsule was also proposed in terms of intermolecular interaction and thermodynamic reason. By taking the advantage of the self-assemble (or self-aggregation) capability, the CHC was employed for drug encapsulation, i.e., doxorubicin, an anticancer molecule; we found in this preliminary evaluation that it reached an efficiency of 46.8%, and a corresponding drug release from the nanocapsules for a time period exceeded 7 days can be achieved in vitro.
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.