Browsing by Issue Date, starting with "2009-11-09"

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A Multifunctional Nanodevice Capable of Imaging, Magnetically Controlling, and In Situ Monitoring Drug Release
(2009-11-09)
Hu, Shang-Hsiu
;
Kuo, Kuan-Ting
;
Tung, Wei-Lin
;
Liu, Dean-Mo
;
Chen, San-Yuan
The multifunctional nanodevice described here integrates nanoscaled imaging, targeting, and controlled drug delivery, as well as the capability to monitor, in situ, the amount of drug released from the nanodevice with single-cell resolution. The nanodevice is composed of a polymer core/single-crystal iron oxide shell nanostructure bonded to a quantum dot. It shows outstanding release and retention characteristics via an external on/off manipulation of a high-frequency magnetic field. Upon magnetic stimulation, the single-crystal iron oxide shell demonstrates formation of nanometer-sized polycrystal domains of varying orientation. This allows a variation between retention and slow release of the drug. Further stimulation causes permanent rupturing of the shell, causing release of the drug in a burst-like manner. The quantum dot bonded to the nanodevice provides optical information for in situ monitoring of the drug release through use of a magnetic field. Remote control drug release from the nanodevice in a cancerous cell line (HeLa) was successfully accomplished using the same induction scenario. When nanodevices equipped with quantum dots are taken into cancerous cells, they are able to provide real-time drug dose information through a corresponding variation in emission spectrum. The nanodevice designed in this study has achieved its potential as a cell-based drug-delivery system for therapeutic applications.
Oblique electron-beam evaporation of distinctive indium-tin-oxide nanorods for enhanced light extraction from InGaN/GaN light emitting diodes
(2009-11-09)
Chiu, C. H.
;
Yu, Peichen
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Chang, C. H.
;
Yang, C. S.
;
Hsu, M. H.
This paper presents a novel and mass-producible technique to fabricate indium-tin-oxide (ITO) nanorods which serve as an omnidirectional transparent conductive layer (TCL) for InGaN/GaN light emitting diodes (LEDs). The characteristic nanorods, prepared by oblique electron-beam evaporation in a nitrogen ambient, demonstrate high optical transmittance (T>90%) for the wavelength range of 450nm to 900nm. The light output power of a packaged InGaN/GaN LED with the incorporated nanorod layer is increased by 35.1% at an injection current of 350mA, compared to that of a conventional LED. Calculations based on a finite difference time domain (FDTD) method suggest that the extraction enhancement factor can be further improved by increasing the thickness of the nanorod layer, indicating great potential to enhance the luminous intensity of solid-state lighting devices using ITO nanorod structures. (C) 2009 Optical Society of America
Comparative studies for Cr(4+):YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers
(2009-11-09)
Huang, J. Y.
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Zhuang, W. Z.
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Huang, W. C.
;
Su, K. W.
;
Hu, C.
We demonstrate comparative studies for Cr(4+):YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr(4+):YAG crystal, respectively. The maximum pulse energies obtained with the Cr(4+):YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively. (C) 2009 Optical Society of America
Comparative studies for Cr4+:YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers
(2009-11-09)
Huang, J. Y.
;
Zhuang, W. Z.
;
Huang, W. C.
;
Su, K. W.
;
Hu, C.
We demonstrate comparative studies for Cr4+:YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr4+:YAG crystal, respectively. The maximum pulse energies obtained with the Cr4+:YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively. (C) 2009 Optical Society of America
A terahertz plastic wire based evanescent field sensor for high sensitivity liquid detection
(2009-11-09)
You, Borwen
;
Liu, Tze-An
;
Peng, Jin-Long
;
Pan, Ci-Ling
;
Lu, Ja-Yu
A highly sensitive detection method based on the evanescent wave of a terahertz subwavelength plastic wire was demonstrated for liquid sensing. Terahertz power spreading outside the wire core makes the waveguide dispersion sensitive to the cladding index variation, resulting in a considerable deviation of waveguide dispersion. Two liquids with transparent appearances, water and alcohol, are easily distinguished based on the waveguide dispersion, which is consistent with theoretical predictions. A melamine alcohol solution with various concentrations is identified successfully, and the detection limit is up to 20ppm, i.e. equivalent to the index variation on the order of 0.01. (C) 2009 Optical Society of America
Homopolymerization and Block Copolymerization of N-Vinylpyrrolidone by ATRP and RAFT with Haloxanthate Inifers
(2009-11-10)
Huang, Chih-Feng
;
Nicolay, Renaud
;
Kwak, Yungwan
;
Chang, Feng-Chih
;
Matyjaszewski, Krzysztof
Difunctional haloxanthate inifers were used for successive reversible addition-fragmentation transfer (RAFT) polymerization of N-vinylprrolidone (NVP) and atom transfer radical polymerization (ATRP) of styrene (St), methyl actylate (MA), and methyl methacrylate (MMA). Since a quantitative dimerization of NVP in the presence of bromoxanthate inifer occurred, two chloroxanthate mifers, S-[1-methyl-4-(6-chloropropionate)ethyl acetate] O-ethyl dithrocarbonate (CPX) and S-[1-methyl-4-(6-chloroisobutyrate)ethyl accetate] O-ethyl dithiocarbonate (CiBX), were synthesized. These two difunctional chloroxanthate imfers were used to prepare PNVP-b-PSi, PNVP-b-PMMA, AND PNVP-b-PMA block copolymers, where each block was synthesized by different polymerization procedures (either RAFT or ATRP). In the RAFT-first approach, well-controlled polymerization of NVP was observed. Well-defined PNVP-b-PSt (M(n, GPC) = 15,000 G/MOL AND M(w)/M(n) < 1.4 and PNVP-b-PMMA (M(n, GPC) = 50,600 g/mol and M(w)/M(n) < 1.3) were successfully synthesized through a subsequent chain extension by ATRP. A reshuffling reaction between propagating acrylate radicals in poor control of the MA chain extenstion. In the ATRP-first approach a well-controlled polymerization was observed only for the ATRP of MMA with the CiBX initrator (M(n) = 13,000 and M(w)/M(n) < 1.3). Significant reshuffling reactions between the xanthate moiety and styryl/acrylate propagating radicals were observed with the CPX initrator. This resulted in poor control and broad molecular weight distribution for the subsequent RAFT chain extension of NVP. Thus, teh chloroxanthate inifers provide synthetic access to well-defined PNVP-b-PSt and PNVP-b-PMMA, but not to PNVP-b-PMA block copolymers.
Super leakage current cut-off device for ternary content addressable memory
(2009-11-10)
Huang
;
Po-Tsang
;
Liu
;
Wen-Yen
;
Hwang
A super leakage current cut-off device for a ternary content addressable memory (TCAM) is provided. For various operations of the TCAM, the device uses the high-end and low-end power gating control transistors to turn on/off the don't-care cells to reduce the leakage current passing through the don't-care cells.
Method for automatic key posture information abstraction
(2009-11-10)
Liao
;
Hong-Yuan
;
Chen
;
Duan-Yu
The method for automatic key posture information abstraction of this invention comprises the steps of: Abstracting from a series of continuous digitized images spatial features of objects contained in said images; abstracting shape features of said objects using a method of probability calculation; detecting key posture information contained in said series of continuous images using a method of entropy calculation; removing redundant key postures; mating obtained key postures with key posture templates stored in a codebook; and encoding mated key postures.
划到生命的更深處，活出生命的光與熱
(2009-11-11)
單國璽
;
開放教育推動中心
;
Open Education Office
課程日期： 2009年11月11日(三) 演講人：單國璽樞機主教內容摘要：單國璽樞機主教以「人生到底有什麼意義」這個問題作為開場，如果要討論思考人生的價值、意義等課題，獲得有意義或快樂的人生。內容：影音實況影音(*.flv檔)
UN聯合國千禧年發展目標與志工行動
(2009-11-11)
林念慈
;
陳建銘
;
開放教育推動中心
;
Open Education Office
課程日期： 2009年11月11日(三) 演講人：林念慈小姐、陳建銘先生內容摘要：在本次課程中，講師向我們介紹了「聯合國千禧年發展目標」－ Millennium Development Goals 」（簡稱MDG）與志工行動的結合。內容：影音實況影音(*.flv檔) 實況影音(*.wmv檔)
Nanocontact resistance and structural disorder induced resistivity variation in metallic metal-oxide nanowires
(2009-11-11)
Lin, Y. F.
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Wu, Z. Y.
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Lin, K. C.
;
Chen, C. C.
;
Jian, W. B.
Several systems of metallic metal-oxide nanowires (NWs), including pure RuO(2) and as-implanted and annealed Ru(0.98)Cu(0.02)O(2) and Ru(0.93)Cu(0.07)O(2) NWs, have been employed in two-probe electrical characterizations by using a transmission electron microscope-scanning tunneling microscope technique with a gold tip. Thermal, mechanical, and electron beam exposing treatments are consecutively applied to reduce the electrical contact resistance, generated from the interface between the NW and the gold tip, so as to evaluate the intrinsic NW resistance. It is found that the residual contact resistance cannot be entirely removed. For each system of metallic metal-oxide NWs, several tens of NWs are applied to electrical characterizations and the total resistances unveil a linear dependence on the ratio of the length to the area of the NWs. As a result, the average resistivity and the contact resistance of the metallic metal-oxide NWs could be evaluated at room temperatures. The average resistivities of pure RuO(2) NWs agree well with the results obtained from standard two- and four-probe electrical-transport measurements. In addition, the as-implanted Cu-RuO(2) NWs reveal disordered crystalline structures in high-resolution TEM images and give higher resistivities in comparison with that of pure RuO(2) NWs. The residual contact resistances of all kinds of metallic metal-oxide NWs unveil, more surprisingly, an approximation value of several kilohms, even though the average resistivities of these NWs change by more than one order of magnitude. It is argued that the ductile gold tip makes one or more soft contacts on the stiff metal-oxide NWs with nanometer roughness and the nanocontacts on the NWs contribute to the electrical contact resistance.
Crystal-less Communications Device and Self-Calibrated Embedded Virtual Crystal Clock Generation Method
(2009-11-12)
Lee, Chen-Yi
;
Yu, Jui-Yuan
This invention discloses a crystal-less communication device and self-calibrated embedded virtual crystal clock generation method. In communication systems, the invention proposes a crystal-less scheme in the device for wireless or wired-line communications. The operation concepts are that the transmitter Device-1 provides Device-2 a reference signal, and Device-2 takes this signal to generate a local signal with the similar frequency that has limited frequency error compared with the one from Device-1. This invention is done via the circuit-design methodology, so it can be implemented from any kinds of circuit implementation processes, especially the CMOS process. As a result, the hardware can be designed in the way of highly integration and extremely low cost. Also, this can largely change and improve existing communications design architecture, hardware cost, and hardware area.
Light emitting device and fabrication method therefor
(2009-11-12)
Chang, Chun-Yen
;
Yang, Tsung Hsi
A light emitting device (LED) structure formed on a Group IV-based semiconductor substrate is provided. The LED structure includes a Group IV-based substrate, an AlN nucleation layer formed on the Group IV-based substrate, a GaN epitaxial layer formed on the AlN nucleation layer, a distributed Bragg reflector (DBR) multi-layer structure formed on the epitaxial layer, and an LED active layer formed on the DBR multi-layer structure.
Nanoparticle structure and manufacturing process of multi-wavelength light emitting devices
(2009-11-12)
CHEN, Wei-Kuo
;
KE, Wen-Cheng
A structure of multi-wavelength light emitting device comprises multi-stacked active layer structure. Each stacked layer comprises lower energy bandgap well 4 and higher energy bandgap barrier layer 3 wherein at least one stacked layer in the device contains nanoparticles. As a result, the emitting wavelengths of the multi-stacked active layer structure consist parts (or all) of the emitting wavelengths come from the stack layers containing nanoparticles, and parts (or all) of the emitting wavelengths come from the stack layers not containing nanoparticles. In another embodiment, parts (or all) of the emitting wavelengths of the multi-stacked active layer structure can be also used to trigger one or more phosphorescences from the phosphors, thus the emitting wavelengths of such a phosphors converted light emitting device may come partially from the multi-stacked active layer itself and partially (or all) from the phosphors.
Method for making very low Vt metal-gate/high-k CMOSFETs using self-aligned low temperature shallow junctions
(2009-11-12)
Chin, Albert
This invention proposes a method for making very low threshold voltage (Vt) metal-gate/high-κ CMOSFETs using novel self-aligned low-temperature ultra shallow junctions with gate-first process compatible with VLSI. At 1.2 nm equivalent-oxide thickness (EOT), good effective work-function of 5.3 and 4.1 eV, low Vt of +0.05 and 0.03 V, high mobility of 90 and 243 cm2/Vs, and small 85° C. bias-temperature-instability<32 mV (10 MV/cm, 1 hr) are measured for p- and n-MOS.
A Strain-Driven Morphotropic Phase Boundary in BiFeO3
(2009-11-13)
Zeches, R. J.
;
Rossell, M. D.
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Zhang, J. X.
;
Hatt, A. J.
;
He, Q.
Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.
A Strain-Driven Morphotropic Phase Boundary in BiFeO(3)
(2009-11-13)
Zeches, R. J.
;
Rossell, M. D.
;
Zhang, J. X.
;
Hatt, A. J.
;
He, Q.
Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO(3)) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.
Glucose sensing by electrochemically grown copper nanobelt electrode
(2009-11-15)
Huang, Ting-Kai
;
Lin, Kuan-Wen
;
Tung, Sze-Ping
;
Cheng, Ta-Ming
;
Chang, I-Chun
A simple design of growing Cu nanobelt (NB) electrode for glucose sensing is presented. Cu NBs were grown directly on carbon electrodes by using electrochemical deposition. The average width, thickness and length of the NBs were about 50 nm, 20 nm and several tens of micrometers, respectively. Cyclic voltammetric (CV) experiments showed that a Cu NB electrode grown by a reduction charge of 0.5 C on a substrate of 0,018 cm(2) enhanced glucose oxidation ability. For glucose sensing, the electrode exhibited a high sensitivity of 79.8 mu A/mM and a measurable detection limit of 10 mu M in amperometric detection. (C) 2009 Elsevier B.V. All rights reserved.
Wavelength-Tunable Laser for Signal Remodulation in WDM Access Networks Using DPSK Downlink and OOK Uplink
(2009-11-15)
Yeh, C. H.
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Chow, C. W.
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Shih, F. Y.
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Wang, C. H.
;
Wu, Y. F.
In this investigation, a simple wavelength-tunable laser based on a Fabry-Perot laser diode (FP-LD) and an erbium-doped fiber amplifier to serve as a downlink signal in a colorless wavelength-division-multiplexed passive optical network (PON) is proposed and experimentally demonstrated. The tuning range of the proposed laser is between 1529.48 and 1560.72 nm, and the output performance of proposed laser is discussed. Colorless operation is implemented by using an FP-LD and a reflective semiconductor optical amplifier in each optical network unit for uplink signal remodulation, respectively. In addition, error-free data signal remodulation using 10-Gb/s downlink differential phase-shift keying and 2.5-Gb/s uplink on-off keying is achieved in a 25-km reach PON.
Supramolecular Assembly of H-Bonded Side-Chain Polymers Containing Conjugated Pyridyl H-Acceptor Pendants and Various Low-Band-Gap H-Donor Dyes Bearing Cyanoacrylic Acid Groups for Organic Solar Cell Applications
(2009-11-15)
Liang, Tzung-Chi
;
Chiang, I-Hung
;
Yang, Po-Jen
;
Kekuda, Dhananjay
;
Chu, Chih-Wei
Novel supramolecular side-chain polymers were constructed by complexation of proton acceptor (H-acceptor) polymers, i.e., side-chain conjugated polymers P1-P2 containing pyridyl pendants, with low-band-gap proton donor (H-donor) dyes S1-S4 (bearing terminal cyanoacrylic acids) in a proper molar ratio. Besides unique mesomorphic properties confirmed by DSC and XPD results, the H-bonds of supramolecular side-chain structures formed by pyridyl H-acceptors and cyanoacrylic acid H-donors were also confirmed by FTIR measurements. H-donor dyes S1-S4 in solid films exhibited broad absorption peaks located in the range of 471-490 nm with optical band-gaps of 1.99-2.14 eV. Furthermore, H-bonded polymer complexes P1/S1-P1/S4 and P2/S1-P2/S4 exhibited broad absorption peaks in the range of 440-462 nm with optical band-gaps of 2.11-2.25 eV. Under 100 mW/cm(2) of AM 1.5 white-light illumination, the bulk heterojunction polymer solar cell (PSC) devices containing an active layer of H-bonded polymer complexes P1/S1-P1/S4 and P2/S1-P2/S4 (as electron donors) mixed with [6,6]-phenyl C(61) butyric acid methyl ester (i.e., PCBM, as an electron acceptor) in the weight ratio of 1:1 were investigated. The PSC device containing H-bonded polymer complex P1/S3 mixed with PCBM (1:1 w/w) gave the best preliminary result with an overall power conversion efficiency (PCE) of 0.50%, a short-circuit current of 3.17 mA/cm(2), an open-circuit voltage of 0.47 V, and a fill factor of 34%. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5998-6013, 2009