Browsing by Issue Date, starting with "2012-06-19"

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Interface control of bulk ferroelectric polarization
(2012-06-19)
Yu, P.
;
Luo, W.
;
Yi, D.
;
Zhang, J. X.
;
Rossell, M. D.
The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.
Nano-hybrid carboxymethyl-hexanoyl chitosan modified with (3-aminopropyl)triethoxysilane for camptothecin delivery
(2012-06-20)
Hsiao, Meng-Hsuan
;
Tung, Tsan-Hua
;
Hsiao, Chi-Sheng
;
Liu, Dean-Mo
;
材料科學與工程學系
Silane-modified amphiphilic chitosan was synthesized by anchoring a silane coupling agent, (3-aminopropyl)triethoxysilane, to a novel amphiphilic carboxymethyl-hexanoyl chitosan (CHC). The chemical structure of this new organic-inorganic hybrid molecule was characterized by FTIR and C-13-, Si-29-nuclear magnetic resonance, while the structural evolution was examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). Experimental results indicated a self-assembly behaviour of molecules into nanopartides with a stable polygonal geometry, consisting of ordered silane layers of 6 nm in thickness. The self-assembly property was found to be influenced by chemical composition and concentration of silane incorporated, while the size can be varied by the amount of anchored silane. It was also demonstrated that such vesicle exhibited excellent cytocompatibility and cellular internalization capability in ARPE-19 cell line, and presented well-controlled encapsulation and release profiles for (S)-(+)-camptothecin. These unique properties render it as a potential drug delivery nanosystem. (C) 2012 Elsevier Ltd. All rights reserved.
交大e-News第120期
(2012-06-20)
Secretariat
;
國立交通大學秘書室
Quasiparticle Dynamics and Phonon Softening in FeSe Superconductors
(2012-06-20)
Luo, C. W.
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Wu, I. H.
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Cheng, P. C.
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Lin, J. -Y.
;
Wu, K. H.
Quasiparticle dynamics of FeSe single crystals revealed by dual-color transient reflectivity measurements (Delta R/R) provides unprecedented information on Fe-based superconductors. The amplitude of the fast component in Delta R/R clearly gives a competing scenario between spin fluctuations and superconductivity. Together with the transport measurements, the relaxation time analysis further exhibits anomalous changes at 90 and 230 K. The former manifests a structure phase transition as well as the associated phonon softening. The latter suggests a previously overlooked phase transition or crossover in FeSe. The electron-phonon coupling constant lambda is found to be 0.16, identical to the value of theoretical calculations. Such a small lambda demonstrates an unconventional origin of superconductivity in FeSe.
一種應用於太陽能電池之共聚高分子
(2012-06-21)
韋光華
;
張耀德
本發明係將一個巨大且共軛的基團引進共軛高分子的側鏈上，不但可以降低共軛高分子的能帶(bandgap)且具有改善電子傳輸效率的效果。導入兩個辛基(octyl)以改善高分子本身的溶解度，且於側鏈導入辛基－菲基－1,3－二氮雜茂(octylphenanthrenyl－imidazole)可以加速高分子內部的電荷分離，因而在照光之後提高了光電流密度，促使其光電轉換效率提升。
Yellow Phosphor Having Oxyapatite Structure, Preparation Method and White Light-Emitting Diode Thereof
(2012-06-21)
CHEN Teng-Ming
;
HUANG Chien-Hao
A yellow phosphor having oxyapatite structure, preparation method and white light-emitting diode thereof are disclosed. The yellow phosphor has a chemical formula of (A1−xEux)8−yB2+y(PO4)6−y(SiO4)y(O1−zSz)2, wherein A and Eu are divalent metal ions, B is a trivalent metal ion, 0
HYBRID CODEC APPARATUS AND METHOD FOR DATA TRASNFERRING
(2012-06-21)
YI Chih-Wei
;
LIU Pin-Chuan
;
LU Hsiao-Heng
In a hybrid codec apparatus for data broadcasting, an encoder divides a source file into N sections, generates N principal encoded data after coding on a first finite field and k additional encoded data after coding on a second finite field, then transmits a group of coefficient encoded data and the N+k encoded data to a decoder. The decoder merges the group of coefficient encoded data and the N+k encoded data, and decodes the N principal encoded data on the first finite field. When the decoder fails to decode the N principal encoded data, the decoder uses the k additional encoded data to assist the data decoding on the second finite field. After the decoding, a recovered source file is produced.
ESD PROTECTION STRUCTURE FOR 3D IC
(2012-06-21)
Chen Kuan-Neng
;
Lai Ming-Fang
;
Chen Hung-Ming
An electrostatic discharge (ESD) protection structure for a 3D IC is provided. The ESD protection structure includes a first active layer, a through-silicon via (TSV) device and a second active layer. The TSV is disposed in the first active layer, and the second active layer is stacked with the first active layer. The second active layer includes a substrate and an ESD protection device, wherein the ESD protection device having a doping area embedded in the substrate, and the ESD protection device electrically connects the TSV device.
CARDIOVASCULAR HEALTH STATUS EVALUATION SYSTEM AND METHOD
(2012-06-21)
CHANG Chia-Chi
;
Hsiao Tsu-Chien
;
Hsu Hung-Yi
A cardiovascular health status evaluation system includes a sensing unit and a computing unit. The sensing unit is for measuring impulses of the cardiovascular circulation of a user. The computing unit is for calculating a standard deviation and an average of time intervals between the impulses in a unit time, and based on a change of a ratio between the standard deviation and average, evaluating the cardiovascular health status of the user. The evaluation index of the aforementioned system includes a personalized parameter (the average), thereby enabling a personalized comparison. A cardiovascular health status evaluation method is also disclosed herein.
ELECTRONIC DEVICE AND METHOD FOR PROTECTING AGAINST DIFFERENTIAL POWER ANALYSIS ATTACK
(2012-06-21)
LIU Po-Chun
;
CHANG Hsie-Chia
;
LEE Chen-Yi
An electronic device and a method for protecting against a differential power analysis attack are disclosed herein. The electronic device includes an encryption/decryption unit, a random number generator and a countermeasure circuit. The encryption/decryption unit can provide an enable signal when encrypting or decrypting more bits of data. The random number generator can generate random data. When receiving the enable signal, the countermeasure circuit can operate according to the bits of data and the random data.
INDEPENDENT COMPONENT ANALYSIS PROCESSOR
(2012-06-21)
Chen Chiu-Kuo
;
Fang Wai-Chi
;
Chua Ericson
;
Fu Chih-Chung
;
Tseng Shao-Yen
An independent component analysis processor conducts real-time operations of multiple-channel parallel signals. The processor includes an input buffering unit for receiving and storing multiple-channel parallel signals, a mean/covariance unit, a centering unit for removing direct current components in the multiple channels parallel signals, a whitening unit for performing a whitening process, and an ICA training unit and an ICA calculating unit that perform an independent component analysis process, to calculate independent components in the multiple-channel parallel signals and separate artifacts from the signals.
螢光材料與應用於發光裝置之發光源
(2012-06-21)
陳登銘
;
周怡君
一種螢光材料，其化學通式如下：A(B1-mEum2+)PO4；其中A係選自Li、Na、K所組成之族群至少其中之一；B係選自Ca、Sr、Ba所組成之族群至少其中之一；其中0.0001＜＝m＜＝0.8。
Infrared Absorption of Gaseous Benzoyl Radical C6H5CO Recorded with a Step-Scan Fourier-Transform Spectrometer
(2012-06-21)
Lin, Shu-Yu
;
Lee, Yuan-Pern
;
應用化學系
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應用化學系分子科學碩博班
;
Department of Applied Chemistry
A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the gaseous transient species benzoyl radical, C6H5CO. C6H5CO was produced either from photolysis of acetophenone, C6H5C(O)CH3, at 248 nm or in reactions of phenyl radical (C6H5) with CO; C6H5 was produced on photolysis of C6H5Br at 248 nm. One intense band at 1838 +/- 1 cm(-1), one weak band at 1131 +/- 3 cm(-1), and two extremely weak bands at 1438 +/- 5 and 1590 +/- 10 cm(-1) are assigned to the C=O stretching (nu(6)), the C-C stretching mixed with C-H deformation (nu(15)), the out-of-phase C1C2C3/C5C6C1 symmetric stretching (nu(10)), and the in-phase C1C2C3/C4C5C6 antisymmetric stretching (nu(7)) modes of C6H5CO, respectively. These observed vibrational wavenumbers and relative IR intensities agree with those reported for C6H5CO isolated in solid Ar and with values predicted for C6H5CO with the B3LYP/aug-cc-pVDZ method. The rotational contours of the two bands near 1838 and 1131 cm(-1) simulated according to rotational parameters predicted with the B3LYP/aug-cc-pVDZ method fit satisfactorily with the experimental results. Additional products BrCO, C6H5C(O)Br, and C6H5C(O)C6H5 were identified in the C6H5Br/CO/N-2 experiments; the kinetics involving C6H5CO and C6H5C(O)Br are discussed.
NEW-TYPE CHITOSAN-BASED HYBRID MACROMOLECULE AND A METHOD FOR PRODUCING OR USING THE MACROMOLECULE
(2012-06-21)
LIU Dean-Mo
;
Tung Tsan-Hua
;
Cheng Hongwei
The invention discloses the synthesis of a new-type chitosan-based hybrid macromolecule and a method for producing or using the macromolecule. This macromolecule comprises an amphiphatic chitosan and a silicon-based coupling agent that is anchored by a chemical bonding. The method for producing the hybrid macromolecule can be easily operated under ambient environment. The produced macromolecule can be self-assembled in an aqueous environment to form a nanocarrier, and has the ability to efficiently encapsulate drugs for a subsequent sustained release purpose. This self-assembled hybrid nanocarrier demonstrated features of excellent biocompatibility, drug loading ability and cellular uptake efficiency.
Magnetic Interaction between Surface-Engineered Rare-Earth Atomic Spins
(2012-06-22)
Lin, Chiung-Yuan
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Li, Jheng-Lian
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Hsieh, Yao-Hsien
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Ou, Keng-Liang
;
Jones, B. A.
We report the ab-initio study of rare-earth adatoms (Gd) on an insulating surface. This surface is of interest because of previous studies by scanning tunneling microscopy showing spin excitations of transition-metal adatoms. The present work is the first study of rare-earth spin-coupled adatoms, as well as the geometry effect of spin coupling and the underlying mechanism of ferromagnetic coupling. The exchange coupling between Gd atoms on the surface is calculated to be antiferromagnetic in a linear geometry and ferromagnetic in a diagonal geometry. We also find that the Gd dimers in these two geometries are similar to the nearest-neighbor and the next-nearest-neighbor Gd atoms in GdN bulk. We analyze how much direct exchange, superexchange, and Ruderman-Kittel-Kasuya-Yosida interactions contribute to the exchange coupling for both geometries by additional first-principles calculations of related model systems.
High-stability oxygen sensor based on amorphous zinc tin oxide thin film transistor
(2012-06-25)
Chen, Yu-Chun
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Chang, Ting-Chang
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Li, Hung-Wei
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Chung, Wan-Fang
;
Wu, Chang-Pei
This research presents a sol-gel derived zinc tin oxide thin film transistor (TFT) as a high-stability oxygen sensor. Due to its high sensitivity, oxygen has been traditionally regarded as having a negative influence on the electrical characteristics of zinc-based TFTs; however, TFTs can also act as an oxygen sensor. After illumination with visible light in oxygen-rich ambient, a significant increase in drain current of nearly 10 4 times occurs with fixed gate and drain voltages. It is expected that an optimized method of illumination can help to reset the electrical characteristics or distinguish the on/off state of this reliable oxygen sensor. (C) 2012 American Institute of Physics. [ http://dx.doi.org/10.1063/1.4731773]
Ultraviolet emission efficiency enhancement of a-plane AlGaN/GaN multiple-quantum-wells with increasing quantum well thickness
(2012-06-25)
Huang, Huei-Min
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Chang, Chiao-Yun
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Lan, Yu-Pin
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Lu, Tien-Chang
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Kuo, Hao-Chung
The defect-induced carrier localization in nonpolar a-plane (Al,Ga)N/GaN multiple quantum wells (MQWs) structures with different well thickness have been investigated. A strong variation of temperature-dependent photoluminescence peak energy was observed and attributed to the existence of the localized states. The degree of carrier localization in these defect-induced states was more prominent in the case of MQWs with the wider well width. In addition, the ultraviolet light emission efficiency revealed a 3-fold enhancement with increasing the well width from 1.6 nm to 7.3 nm, due to the strong carrier localization generated from the quantum-wire-like features formed by the intersection between basal stacking faults and quantum wells. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4730438]
Fabrication and luminescent properties of core-shell InGaN/GaN multiple quantum wells on GaN nanopillars
(2012-06-25)
Chang, J. -R.
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Chang, S. -P.
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Li, Y. -J.
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Cheng, Y. -J.
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Sou, K. -P.
Core-shell InGaN/GaN multiple quantum wells (MQWs) on GaN nanopillars were fabricated by top-down etching followed by epitaxial regrowth. The regrowth formed hexagonal sidewalls and pyramids on the nanopillars. The cathodoluminescence of MQWs blue shifts as the location moves from top to bottom on both the pillar sidewalls and pyramid facets, covering a spectral linewidth of about 100 nm. The MQWs on the pillar sidewalls have a higher InN fraction than those on the pyramid facets. The photoluminescent wavelength is stable over two orders of carrier density change due to the smaller quantum confined Stark effect on the nanopillar facets. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4731629]
An analytical solution for a radial collector well near a stream with a low-permeability streambed
(2012-06-26)
Huang, Ching-Sheng
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Tsou, Pei-Rong
;
Yeh, Hund-Der
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環境工程研究所
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Institute of Environmental Engineering
Radial collector wells are often constructed near a stream to obtain more water and produce smaller drawdown in comparison with traditional vertical wells. This paper aims at developing a mathematical model for describing head distributions induced by pumping in a radial collector well near a stream in an unconfined aquifer. A low permeable streambed between the stream and the aquifer is considered. The first-order free surface equation is used to describe the movement of water table. A point-sink solution of the model is developed first by a general transform combining Fourier sine and cosine transforms and then by Fourier transform and Laplace transform. The transient solution of head distributions for different well types such as the horizontal well or radial collector well can be obtained by integrating the point-sink solution along the well. Based on Darcy's law and the developed solution, an equation for temporal stream depletion rate describing filtration from the stream is then obtained. The steady-state solutions for filtration can be obtained from the transient solution when neglecting the exponential term associated with time. It is found that steady-state filtration depends only on the ratio of streambed permeability over aquifer permeability. Steady-state filtration equals water extraction from a well when the ratio is larger than 10(-2). The streambed is regarded as completely impermeable when the ratio is less than 10(-7). Additionally, the lowest water table happens near the well before occurrence of filtration. The lowest water table moves landward and away from the well after filtration occurs. (C) 2012 Elsevier B.V. All rights reserved.
Optical imaging system
(2012-06-26)
Cheng Chu-Ming
;
Chern Jyh-Long
An optical imaging system including an imaging lens and a spatial light modulator is provided. The imaging system has an aperture stop position. The spatial light modulator is disposed at the aperture stop position of the imaging system to serve as a pupil of the imaging lens. The spatial light modulator is adapted to modulate the light transmission rate of the spatial light modulator to change an amplitude and a phase of a light intensity of the pupil.