Browsing by Issue Date, starting with "2014-11-03"

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Exploring the influence of boundary shapes on emission angular distributions and polarization states of broad-area vertical-cavity surface-emitting lasers
(2014-11-03)
Yu, Y. T.
;
Tuan, P. H.
;
Huang, K. F.
;
Chen, Y. F.
;
電子物理學系
We design the stadium-shaped and rectangular vertical-cavity surface-emitting lasers (VCSELs) to investigate the influence of boundary shapes on the emission angular distributions and polarization states. For the stadium-shaped VCSELs, the emission angular distribution prefers to be almost omnidirectional because the lasing mode with purely scarred structure is seldom to be excited. On the contrary, the rectangular VCSELs usually generate dominant lasing modes with the morphology of quasi-periodic linear ridges, which can make emission angular distribution to be concentrated on the certain direction. From the polarization-resolved light-current curves, the stadium-shaped VCSEL is quite prone to exhibit numerous abrupt changes (kinks) associated with polarization switching with increasing current, whereas for rectangular VCSEL there is no conspicuous kink to be seen during a wide range of current changing from near to far above lasing threshold. (C) 2014 Optical Society of America
In-situ doping of erbium in hydrogenated amorphous carbon by low temperature metalorganic radio frequency plasma enhanced chemical vapor deposition
(2014-11-03)
Hsu, Hui-Lin
;
Leong, Keith R.
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Halamicek, Michael
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Teng, I-Ju
;
Mahtani, Pratish
A significant improvement in the photoluminescence of erbium doped amorphous carbon (a-C: H(Er)) is reported. The effects of the RF power on the anode and cathode a-C: H films were investigated in terms of the microstructural and local bonding features. It was determined that Er doped a-C: H films should be placed on the anode to obtain wider bandgap and lower percentage of sp(2) carbon bonding. The metalorganic compound, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) Erbium(+III) or Er(fod)(3), was incorporated in-situ into an a-C: H host by metalorganic rf plasma enhanced chemical vapor deposition. This technique provides the capability of doping Er in a vertically uniform profile. The high erbium concentration (3.9 at.%), partial fluorination of the surrounding ligands, and the large optical bandgap of the host a-C: H are the primary factors that enable enhancement of the photoluminescence. (C) 2014 Elsevier B. V. All rights reserved.
Influence of patterned sapphire substrates with different symmetry on the light output power of InGaN-based LEDs
(2014-11-03)
You, Yao-Hong
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Su, Vin-Cent
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Ho, Ti-En
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Lin, Bo-Wen
;
Lee, Ming-Lun
This paper aims to investigate the light output power (LOP) of InGaN-based light-emitting diodes (LEDs) grown on patterned sapphire substrates (PSSs) with different symmetry. The GaN epitaxial layers grown on the hexagonal lattice arrangement PSS (HLAPSS) have a lower compressive strain than the ones grown on the square lattice arrangement PSS (SLAPSS). The quantum-confined Stark effect (QCSE) is also affected by the residual compressive strain. Based on the experimentally measured data and the ray tracing simulation results, the InGaN-based LED with the HLAPSS has a higher LOP than the one with the SLAPSS due to the weaker QCSE within multiple-quantum wells (MQWs).
Method for forming vertical type sensor
(2014-11-04)
Zan Hsiao-Wen
;
Meng Hsin-Fei
;
Dai Ming-Zhi
;
Chao Yu-Chiang
The present invention provides a vertical type sensor, including a substrate; a first electrode formed on the substrate; a sensing layer formed on the first electrode layer and reactive to a target substance, wherein the first electrode layer is interposed between the substrate and the sensing layer; and a second electrode layer formed on the sensing layer and having a plurality of openings, wherein the sensing layer is interposed between the first electrode layer and the second electrode layer, and the target substance contacts the sensing layer via the plurality of openings. The vertical type sensor of the present invention provides instant, sensitive and rapid detection.
Human identification system by fusion of face recognition and speaker recognition, method and service robot thereof
(2014-11-04)
Song Kai-Tai
;
Chien Shuo-Cheng
;
Lin Chao-Yu
;
Chen Yi-Wen
;
Chen Sin-Horng
The present invention discloses a human identification system by fusion of face recognition and speaker recognition, a method and a service robot thereof. The system fuses results of the face recognition and the speaker recognition, and further uses confidence index to estimate the confidence level of the two recognition results. If only one of the confidence indices of the two recognition results reaches the threshold, then only this result is used as the output. If both confidence indices of the two recognition results reach the threshold, then the two recognition results are fused to output as a final result.
Synthesis of hyperbranched polythiophenes containing tetrachloroperylene bisimide as bridging moiety for polymer solar cells
(2014-11-05)
Yang, Sheng-Hsiung
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Lin, Tz-Shiuan
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Huang, Yu-Zhang
;
Li, Husan-De
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Chao, Yu-Chiang
The goal of this research is to synthesize the hyperbranched polythiophene derivatives (P1 and P4) containing tetrachloroperylene bisimide as bridging moiety for investigation of thermal, electrochemical, and opto-electrical properties of these derivatives. The polymers (P2 and P3) containing soft alkyl spacer as bridging moiety and linear poly(3-hexylthiophene) (P3HT) were also synthesized for comparison in this study. Polymers with high regioregularity were synthesized via the Universal Grignard metathesis polymerization. The GPC results showed that molecular weights of hyperbranched polythiophenes are higher than that of P3HT. The TGA experiments revealed a first-stage weight loss at about 300 degrees C for all polymers; besides, polymers containing rigid tetrachloroperylene bisimide groups possess less weight loss than P3HT after heating, indicative of enhanced thermal stabilities. The UV-vis absorption maxima of hyperbranched polymers are similar to that of P3HT in film state, while their absorption shoulder bands are stronger than that of P3HT, indicating stronger interchain interaction and shorter distance between backbones by the introduction of bridge architecture. Moreover, an attenuation of fluorescent intensity was found for those hyperbranched polymers, implying reduced recombination of excitons to emit light and more opportunity for carriers to migrate to both electrodes. Electrochemical analysis showed that introducing hyperbranched structure resulted in decreasing both LUMO and HOMO levels of polymers. All polymers were used for fabrication of polymer solar cells with the configuration of ITO/PEDOT/polymer:PC60BM (1:2 w/w)/LiF/Al to evaluate their performance. The power conversion efficiency (PCE) of the P3HT:PC60BM-based device is 0.54%, while devices based on hyperbranched polymers showed PCE values in the range of 0.45-0.84%. The morphological study of polymer:PC60BM blend films was performed by AFM for interpretation of efficiency trend of devices. (C) 2014 Elsevier Ltd. All rights reserved.
交大e-News第174期
(2014-11-05)
Secretariat
;
國立交通大學秘書室
An efficient wet electrostatic precipitator for removing nanoparticles, submicron and micron-sized particles
(2014-11-05)
Chen, Tzu-Ming
;
Tsai, Chuen-Jinn
;
Yan, Shaw-Yi
;
Li, Shou-Nan
;
環境工程研究所
An efficient wire-to-plate single-stage wet electrostatic precipitator (WESP) was designed and tested to control nanoparticles, submicron and micron-sized particles emitted from semiconductor manufacturing processes. Tungsten-wires of 0.36 mm in diameter were used as discharge electrodes and a fixed voltage of -15 kV was supplied to generate the electric field and corona ions. Fine water mist at room temperature was used to quench the high temperature exhaust gas to enhance particle condensation growth and improve the collection efficiency of nanoparticles. Experimental results showed that without fine water mist, nanoparticle collection efficiency was 67.9-92.9%, which was greatly enhanced to 99.2-99.7% when the WESP was operated with fine water mist. A predictive method was developed to calculate the particle collection efficiency equation eta(%) in the form as eta(%) = [1 - exp(-alpha(N-De)(beta) + gamma)] x 100%, in which alpha, beta and gamma are regression coefficients and N-De is the Deutsch number. Good agreement was obtained between present predictions and experimental data. For longer term operation, the periodic wall-cleaning water was used to clean discharge electrodes and collection electrodes regularly. In the field tests, the total collection efficiencies (40 <= d(p) <= 8100 nm) of the WESP were found to maintain greater than 98.7% and 97.3% for continuous operation for 35 and 22 day at fab A and fab B, respectively. (C) 2014 Elsevier B.V. All rights reserved.
The effect of fluorescent nanodiamonds on neuronal survival and morphogenesis
(2014-11-05)
Huang, Yung-An
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Kao, Chun-Wei
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Liu, Kuang-Kai
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Huang, Hou-Syun
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Chiang, Ming-Han
Nanodiamond (ND) has emerged as a promising carbon nanomaterial for therapeutic applications. In previous studies, ND has been reported to have outstanding biocompatibility and high uptake rate in various cell types. ND containing nitrogen-vacancy centers exhibit fluorescence property is called fluorescent nanodiamond (FND), and has been applied for bio-labeling agent. However, the influence and application of FND on the nervous system remain elusive. In order to study the compatibility of FND on the nervous system, neurons treated with FNDs in vitro and in vivo were examined. FND did not induce cytotoxicity in primary neurons from either central (CNS) or peripheral nervous system (PNS); neither did intracranial injection of FND affect animal behavior. The neuronal uptake of FNDs was confirmed using flow cytometry and confocal microscopy. However, FND caused a concentration-dependent decrease in neurite length in both CNS and PNS neurons. Time-lapse live cell imaging showed that the reduction of neurite length was due to the spatial hindrance of FND on advancing axonal growth cone. These findings demonstrate that FNDs exhibit low neuronal toxicity but interfere with neuronal morphogenesis, and should be taken into consideration when applications involve actively growing neurites (e.g. nerve regeneration).
Profiling vertical distribution of scalants in RO membranes by LA-ICP-MS and fouling models
(2014-11-05)
Lin, Justin Chun-Te
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Wang, Tsinghai
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Ku, Yu-Hsuan
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Hsieh, Yi-Kong
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Wang, Chu-Fang
The vertical distribution of scalants as a result of 24 h of filtration of simulated low-level radioactive liquid waste in the reverse osmosis (RO) membranes was characterized by means of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Our results suggested that the development of scalants is associated with the formation of metal hydroxide colloids, while these colloids might penetrate relatively deeper into the membrane under the acid environment than under the alkaline environment. Fitting with a two-phase fouling Hermia\'s model suggested that the development of cake-like scalants in the first 5 h under alkaline environment is responsible for hindering the assess of metal hydroxides into the membrane so that they would not penetrate as deep as they do under the acid environment. (C) 2014 Elsevier B.V. All rights reserved.
APPARATUS FOR IDENTIFYING FALLS AND ACTIVITIES OF DAILY LIVING
(2014-11-06)
Yang Bing-Shiang
;
Wang Chih-Chung
;
Liao Sain-Ting
The present invention provides and apparatus for distinguishing falls from activities of daily living (ADLs). First, the human movements and muscle activities would be obtained by an electromyography measuring unit and/or an inertia measuring unit to record ADLs, and falls would be distinguished from ADLs to trigger the protecting devices in time to prevent or decrease injury. In addition, the apparatus would be preset for different operational conditions to adapt different users by a setting unit to increase accuracy. Finally, the moving distance and the direction of the user would be obtained by the electromyography measuring unit and/or the inertia measuring unit to obtain the location thereof in an interior space.
High-performance HfO2/ZrO2/IGZO thin-film transistors deposited using atmospheric pressure plasma jet
(2014-11-06)
Wu, Chien-Hung
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Chang, Kow-Ming
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Hsu, Hsin-Yu
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
An atmospheric pressure plasma jet (APPJ) deposition technology that is employed for the preparation of transparent oxide semiconductors film using an eco-friendly water-based metal salt solution as a precursor is presented. Through the use of APPJ indium-gallium-zinc-oxide (IGZO) film as the channel material and a high-k dielectric HfO2/ZrO2 gate stack, IGZO-based transparent thin-film transistors (TFTs) were fabricated and characterised. The HfO2/ZrO2/IGZO-TFTs by APPJ demonstrated excellent electrical characteristics, including a low V-th of 0.63 V, a small subthreshold swing of 0.37 V/dec, a high mobility of 40 cm(2)/V-s and a large I-on/I-off ratio of 7 x 10(8).
Synthesis and Molecular Properties of Tricyclic Biselenophene-Based Derivatives with Nitrogen, Silicon, Germanium, Vinylidene, and Ethylene Bridges
(2014-11-07)
Pao, Yu-Chieh
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Chen, Yung-Lung
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Chen, Yen-Ting
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Cheng, Sheng-Wen
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Lai, Yu-Ying
A new class of biselenophene-based materials including an sp(3)-silicon-bridged diselenosilole (DSS), an sp(3)-germanium-bridged diselenogermole (DSG), and an sp(3)-nitrogen-bridged diselenopyrrole (DSP) as well as an sp(2)-vinylidene-bridged dicyanodiselenofulvene (CDSF), a diacetylenediselenofulvene (ADSF), and a dioctylethylene-bridged benzodiselenophene (BDS) have been successfully synthesized and characterized. The bridging moieties play an important role in determining the optical and electrochemical properties. The six brominated derivatives are ready to construct various biselenophene-based conjugated materials with tunable properties for organic photovoltaics and field effect transistors.
Synthesis of novel platinum complex core as a selective Ag+ sensor and its H-bonded tetrads self-assembled with triarylamine dendrimers for electron/energy transfers
(2014-11-07)
Shellaiah, Muthaiah
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Raju, Mandapati V. Ramakrishnam
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Singh, Ashutosh
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Lin, Hsin-Chieh
;
Wei, Kung-Hwa
A novel platinum complex PtC with a tri-armed uracil hydrogen-bonded (H-bonded) unit was synthesized via a modular synthetic approach and characterized by H-1, C-13 NMR and MALDI-TOF mass spectroscopies. Two H-bonded tetrads, PtC-(TPAD1)(3) and PtC-(TPAD2)(3), based on a metal core PtC complexed with two generations of triarylamine dendrimers, TPAD1 and TPAD2 (with electron-donating nature), were successfully constructed with improved organic solubility via a classical H-bonded self-assembly approach. Supramolecular H-bonding in solution and solid state was elucidated by H-1 NMR titrations, IR spectral studies and time resolved photoluminescence (TRPL) measurements. The electron/energy transfers, as well as the self-assemblies of supramolecular tetrads, were established by UV-Vis and PL titrations and AFM morphological studies. Furthermore, metal complex core PtC showed selective sensitivity towards Ag+ ions through fluorescence turn-off responses without any interference from other common metal ions. The 1 : 1 binding stoichiometry and complexation mechanism between the probe and Ag+ ion was established by H-1 NMR titration. Moreover, PL reversibility of PtC + Ag+ could be achieved on addition of PMDTA.
A fluorescence turn-on probe for cysteine and homocysteine based on thiol-triggered benzothiazolidine ring formation
(2014-11-07)
Liu, Shi-Rong
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Chang, Chao-Yiu
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Wu, Shu-Pao
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應用化學系
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Department of Applied Chemistry
We synthesized a new coumarin-based probe TP, containing a disulfide moiety, to detect biothiols in cells. A fluorescence turn-on response is induced by the thiol-disulfide exchange of the probe, with subsequent intramolecular benzothiazolidine ring formation giving rise to a fluorescent product. The probe exhibits an excellent selectivity for cysteine (Cys) and homocysteine (Hcy) over glutathione (GSH) and other amino acids. The fluorescent probe also exhibits a highly sensitive fluorescence turn-on response to Cys and Hcy with detection limits of 0.8 mu M for Cys and 0.5 mu M for Hcy. In addition, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that the probe TP could be an efficient fluorescent detector for thiols in living cells. (C) 2014 Elsevier B.V. All rights reserved.
Multicomponent Reactions of Phosphines, Diynedioates, and Aryl Aldehydes Generated Furans Appending Reactive Phosphorus Ylides through Cumulated Trienoates as Key Intermediates: A Phosphine alpha-Addition-delta-Evolvement of an Anion Pathway
(2014-11-07)
Deng, Jie-Cheng
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Chuang, Shih-Ching
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應用化學系
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Department of Applied Chemistry
Multicomponent reactions of phosphines, diynedioates, and aryl aldehydes have been demonstrated, providing trisubstituted furans appending reactive phosphorus ylides, through cumulated trienoates as key intermediates. The proposed trienoate intermediates, 1,5-dipolar species formed via nucleophilic alpha-attack of phosphines toward diynedioates (alpha-addition-delta-evolvement of an anion, abbreviated alpha A delta E), undergo addition to aryl aldehydes followed by 5-endo-dig cyclization, proton transfer, and resonance to give trisubstituted furans. Furthermore, the phosphorus ylides are oxidized to alpha-keto ester furans and utilized as Wittig reagents.
Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics
(2014-11-07)
Persson, Rasmus A. X.
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Voulgarakis, Nikolaos K.
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Chu, Jhih-Wei
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生物科技學系
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生物資訊及系統生物研究所
Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential phi in coupling to the other equations of FHD. The resulting phi-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of phi-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of phi-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 angstrom, the phi-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics. (C) 2014 AIP Publishing LLC.
Self-Assembly of Tetraphenylethene-Based [2]Catenane Driven by Acid Base-Controllable Molecular Switching and Its Enabled Aggregation-Induced Emission
(2014-11-07)
Raju, Mandapati V. Ramakrishnam
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Lin, Hong-Cheu
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材料科學與工程學系
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Department of Materials Science and Engineering
A novel [2]catenane 2-C based on the tetraphenylethene (TPE) and orthogonal H-bonded cleft was successfully constructed. VT-NMR and TEM measurements demonstrate that 2-C could be self-assembled to induce an enabled aggregation-induced emission (AIE) in aqueous solution and solid state owing to its TPE unit as well as present unique acid-base controllable and reversible supramolecular self-assembled nanosuperstructures by interplay of a wide range of noncovalent interactions.
Dynamic study on the transformation process of gold nanoclusters
(2014-11-07)
Ma, Xiaoqian
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Wen, Xiaoming
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Toh, Yon-Rui
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Huang, Kuo-Yen
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Tang, Jau
In this paper, the transformation process from Au-8 to Au-25 nanoclusters (NCs) is investigated with steady state fluorescence spectroscopy and time-resolved fluorescence spectroscopy at various reaction temperatures and solvent diffusivities. Results demonstrate that Au-8 NCs, protected by bovine serum albumin, transform into Au-25 NCs under controlled pH values through an endothermic reaction with the activation energy of 74 kJ mol(-1). Meanwhile, the characteristic s-shaped curves describing the formation of Au-25 NCs suggest this process involves a diffusion controlled growth mechanism.
Deformative Transition of the Menschutkin Reaction and Helical Atropisomers in a Congested Polyheterocyclic System
(2014-11-07)
Chang, Yung-Yu
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Ho, Tse-Lok
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Chung, Wen-Sheng
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應用化學系
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Department of Applied Chemistry
A 4,7-phenanthroline polycyclic 1A designed for probing the limits of the Menschutkin reaction was synthesized in a six-step sequence. The rotational barrier of the phenyl ring nearby the N-methyl group in rac-2A was estimated to be >= 18.1 kcal/mol from VT-NMR experiments, making them a new type of helical atropisomer. The methylation rate constants of 9 and 1A with MeI was found to be 2.22 x 10 (4) and 9.62 x 10 (6) s(1) mol(1) L, respectively; thus, the formation rate of (P/M)-2A is one of the slowest rates ever reported for a Menschutkin reaction. The N-methyl protons in (P/M)-2A exhibit a significant upfield shift (Delta delta 1.0 ppm) in its H-1 NMR, compared to those without a nearby phenyl, indicating a strong CH-pi interaction is involved. Conformational flexibility in dipyridylethene 9 is clearly shown by its complexation with BH3 to form helical atropisomers (P,P/M,M)-10. The pKa values of the conjugate acids of 1A and 9 in acetonitrile were determined to be 4.65 and 5.07, respectively, which are much smaller compared to that of pyridine 14a (pK(a) = 12.33), implying that the basicity, nucleophilicity, and amine alkylation rates of 1A and 9 are markedly decreased by the severe steric hindrance of the flanking phenyl rings in the polyheterocycles.