Browsing by Issue Date, starting with "2009-07-02"

Now showing 1 - 20 of 50308

Apparatus And Method For Executing The Handoff Process In Wireless Networks
(2009-07-02)
Lin, Yi-Bing
;
Hsu, Shih-Feng
Disclosed is an apparatus and method for executing the handoff process in the wireless networks. The apparatus comprises a processor to execute an identity checking mechanism. When a wireless network station wants to move from a source AP to a destination AP, the wireless network station sends an authentication request message to the destination AP. The identity checking mechanism searches a R0KH table of the destination AP for the R0KH ID contained in the authentication request message, and determines a setting parameter for executing a handoff process. Thereby, the wireless network station may execute the handoff process. A R0KH table of an AP consists of all IDs of R0KHs that can be accessed by the AP.
Micro-optical pickup
(2009-07-02)
Lee, Chi-Hung
;
Chiu, Yi
;
Shieh, Han-Ping D
A dynamic micro-machined optical device is applied in a micro-optical pickup. The micro-optical pickup includes an actuator and a dynamic grating, wherein the actuator may be a cantilever beam electrostatic actuator, a scratch drive actuator, a magnetic actuator or an electromagnetic actuator; and the actuator is controlled by applying an external voltage. The position of the dynamic grating is switchable between on and off the optical axis. When the external voltage is applied, the on-axis dynamic grating splits the light from a laser diode into multi-beams and the micro-optical pickup can rapidly retrieve information on the disk by simultaneously reading multi-tracks on the disk with multi low energy beams. When the external voltage is turned-off, the dynamic grating is off the optical axis and the light from the laser diode will pass directly and write information into the disk with single high energy beam.
COHERENT TUNABLE FILTER APPARATUS AND WIRELESS COMMUNICATION FRONT-END CIRCUIT THEREOF
(2009-07-02)
Kuo, Chien-Nan
;
Shih, Horng-Yuan
;
Pang, Yi-Hsin
A front-end circuit with coherent tunable filters is provided. The circuit includes a first filter, an amplifier, and a second filter. The amplifier is coupled to the first filter, and the second filter is coupled to the amplifier. Furthermore, the amplifier is placed between the first and second filters. The first filter has a first tunable intermediate frequency, and is used to filter a received signal. The amplifier is used to amplify the output of the first filter. The second filter has a second tunable intermediate frequency, and is used to filter the output of the amplifier. The first and second intermediate frequencies have a coherent-tuning relation with each other.
Dynamic visual tracking control of a mobile robot with image noise and occlusion robustness
(2009-07-02)
Tsai, Chi-Yi
;
Song, Kai-Tai
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a robust visual tracking control design for a nonholonomic mobile robot equipped with a tilt camera. This design aims to allow the mobile robot to keep track of a dynamic moving target in the camera's field-of-view; even though the target is temporarily fully occluded. To achieve this, a control system consisting of a visual tracking controller (VTC) and a visual state estimator (VSE) is proposed. A novel visual interaction model is derived to facilitate the design of VTC and VSE. The VSE is responsible for estimating the optimal target state and target image velocity in the image space. The VTC then calculates the corresponding command velocities for the mobile robot to work in the world coordinates. The proposed VSE not only possesses robustness against the image noise, but also overcomes the temporary occlusion problem. Computer simulations and practical experiments of a mobile robot to track a moving target have been carried out to validate the performance and robustness of the proposed system. (C) 2008 Elsevier B.V. All rights reserved.
DEVICE FOR ACCURATELY MEASURING AMPLIFIER'S OPEN-LOOP GAIN WITH DIGITAL STIMULI
(2009-07-02)
HONG, Hao-Chiao
A device capable of receiving one or more digital stimulus signals and accurately measuring an open-loop gain of an amplifier comprises: a digital charge converter (DCC), a charge integrator, an A/D converter, a control logic circuit and an arithmetic logic unit (ALU). The DCC and the charge integrator are composed of a plurality of switches, one or more sampling capacitor, at least one integrating capacitor and an operational amplifier under test (OPAUT) with a single-ended output or differential-ended outputs. The DCC, the charge integrator, and the A/D converter are controlled by control signals generated by the logic control circuit and can be reconfigured as a first-order Sigma-Delta modulator capable of receiving at least one of the digital input stimulus signals. The ALU calculates the open-loop gain of the OPAUT with single-ended output or differential-ended outputs according to the digital stimulus signals and the digital output of the first-order Sigma-Delta modulator.
Optical element apparatus for two-dimensional controllable localized partition backlight module
(2009-07-02)
Tien, Chung-Hao
;
Lu, Yen-Hsing
;
Cheng, Yu-Kuo
;
Lu, Po-Yi
The optical element apparatus for two-dimensional controllable localized partition backlight module is disclosed. The optical element apparatus comprises of a plurality of optical units which include a plurality of point light sources, light guides and collimating sheets. The point light source is located at the center of the light guide. The light guide includes the incident surface, the bottom place connecting with the light incident surface, and the light output surface. There are micro structures on the bottom place of the light guide and the top surface of the collimating sheet.
Entangled Quantum Nonlinear Schroumldinger Solitons
(2009-07-03)
Lai, Yinchieh
;
Lee, Ray-Kuang
;
光電工程學系
;
Department of Photonics
Considered as a multipartite quantum system, time-multiplexed nonlinear Schroumldinger solitons after collision are rigorously proved to become quantum entangled in the sense that their quadrature components of suitably selected internal modes satisfy the inseparability criterion. Clear physical insights for the origin of entanglement are given, and the required homodyne local oscillator pulse shape for optimum entanglement detection is determined.
Sulfonated poly(ether ether ketone) membranes crosslinked with sulfonic acid containing benzoxazine monomer as proton exchange membranes
(2009-07-03)
Ye, Yun-Sheng
;
Yen, Ying-Chieh
;
Cheng, Chih-Chia
;
Chen, Wen Yi
;
Tsai, Li-Tuan
The incorporation of benzoxazine (Ba) or sulfonic acid containing benzoxazine (SBa) as a crosslinking agent in SPEEK proton exchange membrane (PEM) can substantially improve the SPEEK membrane performance. The SPEEK-SBa membranes give higher effective selectivity than corresponding SPEEK-Ba membranes under close crosslinker loading and thus are more suitable to be used in direct methanol fuel cells. The best achieved SPEEK-SBa composition (SBa40) gives reasonable proton conductivity (0.91 x 10(-2) S cm(-1)) but significantly lower methanol permeability (6.5 x 10(-8) 52 cm(-1)). The achieved effective selectivity (Phi = SPEEK-SBa40: 14.0 x 10(4) S s cm(-3)) is substantially higher than the plain SPEEK (Phi = 7.24 x 10(4) S s cm(-3)) which has great potential for practical applications in DMFCs. (C) 2009 Elsevier Ltd. All rights reserved.
Using the cationic surfactants N-cetyl-N-methylpyrrolidinium bromide and 1-cetyl-3-methylimidazolium bromide for sweeping-micellar electrokinetic chromatography
(2009-07-03)
Su, Hsiu-Li
;
Lan, Min-Tsu
;
Hsieh, You-Zung
;
應用化學系
;
Department of Applied Chemistry
This paper describes a sweeping-micellar electrokinetic chromatography (sweeping-MEKC) technique for the determination of seven benzodiazepines. using, as sweeping carriers, the ionic liquid-type cationic surfactants 1-cetyl-3-methylimidazolium bromide (C(16)MIMBr) and N-cetyl-N-methylpyrrolidinium bromide (C(16)MPYB). These surfactants resemble the commonly employed cationic surfactant cetyltrimethylammonium bromide (CTAB), but they provide different separation efficiencies. We optimized the separation and sweeping conditions, including the pH, the concentrations of organic modifier and surfactant, and the sample injection volume. Adding C(16)MIMBr or C(16)MPYB to the background electrolyte enhanced the separation efficiency and detection sensitivity during the sweeping-MEKC analyses of the benzodiazepines. C(16)MIMBr enhanced the sensitivity for each benzodiazepine 31-59-fold: C(16)MPYB, 86-165-fold. In the presence of C(16)MPYB, the limits of detection for the seven analytes ranged from 4.68 to 9.75 ng/mL. We adopted the sweeping-MEKC conditions optimized for C(16)MPYB to satisfactorily analyze a human urine sample spiked with the seven benzodiazepines. To minimize the matrix effects, we subjected this urine sample to off-line solid phase extraction (SPE) prior to analysis. The recoveries of the analytes after SPE were satisfactory (ca. 77.0-88.3%). Our experimental results reveal that the cationic surfactant C(16)MPYB exhibits superior sweeping power relative to those of C16MIMBr and CTAB and that it can be applied in sweeping-MEKC analyses for the on-line concentrating and analyzing of benzodiazepines present in real samples at nanogram-per-milliliter concentrations. (C) 2009 Elsevier B.V. All rights reserved.
Fullerene Derivatives Incorporating Phosphoramidous Ylide and Phosphoramidate: Synthesis and Property
(2009-07-03)
Chen, Sheng-Yuan
;
Cheng, Rai-Long
;
Tseng, Cheng-Kuo
;
Lin, Ya-Shiuan
;
Lai, Li-Hsiang
The reaction of dimethyl acetylenedicarboxylate (DMAD) with C(60) in the presence of hexamethylphosphorous triamide (HMPT) or hexaethylphosphorus triamide (HEPT) results in fullerene derivatives incorporating HMPT or HEPT ylides. The ylide derivatives exhibit unusual electronic absorptions in the visible region (435-660 nm), likely due to the presence of the ylide moiety. Electrochemical studies revealed that the first reductive potential of these compounds was more negative relative to those of both C(60) (Delta E = 130 mV) and a simple Bingel adduct (Delta E = 90 mV). A phosphoramidate side product, which resulted from the addition of HMPT or HEPT to C(60) followed by hydrolysis, exhibited a featureless absorption spectrum in the visible region and a more negative first reductive potential (Delta E = 70 mV) relative to that of C(60).
Crystal symmetry breaking of wurtzite to orthorhombic in nonpolar a-ZnO epifilms
(2009-07-06)
Kuo, C. C.
;
Liu, W. -R.
;
Hsieh, W. F.
;
Hsu, C. -H.
;
Hsu, H. C.
Crystal symmetry breaking of wurtzite C-6V to orthorhombic C-2V due to in-plane anisotropic strain was investigated for nonpolar (11 (2) over bar0) ZnO epifilms grown on the R-sapphire. X-ray diffraction results reveal the epilayer is subjected to a compressive strain along the polar c-axis and tensile strains along both a-[11 (2) over bar0] surface normal and in-plane p-[1 (1) over bar 00] axis. The polarized Raman spectra of E-2 modes reveal violation of the C-6V selection rules. Oppositely, the C-2V configuration satisfies the selection rules for the Raman modes. The observed E-1 and E-2 bands in polarized optical reflection and photoluminescence spectra confirm the anisotropic strain causes the structure change to the orthorhombic one. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3159470]
交大e-News第051期
(2009-07-06)
Secretariat
;
國立交通大學秘書室
High-efficiency Q-switched dual-wavelength emission at 1176 and 559 nm with intracavity Raman and sum-frequency generation
(2009-07-06)
Chang, Y. T.
;
Chang, H. L.
;
Su, K. W.
;
Chen, Y. F.
;
電子物理學系
An efficient Q-switched dual-wavelength laser with self-frequency Raman conversion in composite Nd:YVO(4) and intracavity sum-frequency generation in BBO is reported. With an input pump power of 17.5 W, average power of 0.53 W at the first-Stokes 1176 nm and average power of 1.67 W at the sum-frequency mixed 559 nm are simultaneously generated at a pulse repetition rate of 100 kHz, corresponding to a total conversion efficiency of 12.5%. (C) 2009 Optical Society of America
Efficient high-peak-power AlGaInAs eye-safe wavelength disk laser with optical in-well pumping
(2009-07-06)
Chang, H. L.
;
Huang, S. C.
;
Chen, Yi-Fan
;
Su, K. W.
;
Chen, Y. F.
We have demonstrated an efficient high-peak-power AlGaInAs eye-safe wavelength disk laser at 1555 nm. The quantum defect and the thermal load are significantly reduced by pumping the quantum well directly. The overall conversion efficiency is enhanced over three times compared with the barrier pumping method. With a pump peak power of 3.7 kW, an output peak power of 0.52 kW is generated at a pulse repetition rate of 20 kHz. (C) 2009 Optical Society of America
Eliminate coherence spike in reflection-type pump-probe measurements
(2009-07-06)
Luo, C. W.
;
Wang, Y. T.
;
Chen, F. W.
;
Shih, H. C.
;
Kobayashi, T.
The coherence spike of femtosecond laser pulses in the reflection-type pump-probe measurements has been systematically studied in the semiconductor (100) InP. By varying the setup of the pump-probe measuring system, i.e. the polarizations of pump and probe pulses, the incident angles of pump and probe beams, and the interval of delay time between pump and probe pulses, the dramatic changes in the strength of coherence spike could be clear observed. Furthermore, the proposed methods to remove the coherence spike from the transient reflectivity curves have been demonstrated in the time-domain measurements. (C) 2009 Optical Society of America
Plasmonic-enhanced polymer photovoltaic devices incorporating solution-processable metal nanoparticles
(2009-07-06)
Chen, Fang-Chung
;
Wu, Jyh-Lih
;
Lee, Chia-Ling
;
Hong, Yi
;
Kuo, Chun-Hong
We have explored the effect of gold nanoparticle (Au NP)-induced surface plasmons on the performance of organic photovoltaic devices (OPVs). The power conversion efficiency of these OPVs was improved after blending the Au NPs into the anodic buffer layer. The addition of Au NPs increased the rate of exciton generation and the probability of exciton dissociation, thereby enhancing the short-circuit current density and the fill factor. We attribute the improvement in device performance to the local enhancement in the electromagnetic field originating from the excitation of the localized surface plasmon resonance. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3174914]
Ab initio studies of excited electronic state S(2) of pyrazine and Franck-Condon simulation of its absorption spectrum
(2009-07-07)
He, Rongxing
;
Zhu, Chaoyuan
;
Chin, Chih-Hao
;
Lin, Sheng Hsien
;
應用化學系分子科學碩博班
The equilibrium geometry and 24 vibrational-normal-mode frequencies of the excited state S(2)((1)B(2u))of pyrazine are calculated and characterized using the complete active space self-consistent field method in the adiabatic representation. The displaced harmonic oscillator approximation is used to simulate the absorption spectrum of the S(2)((1)B(2u)) state along with the Franck-Condon approximation. It is found that the totally symmetric mode v(1) plays the most important role and this exactly agrees with the experimental observations. The simulated absorption spectrum agrees well with those experimentally observed. This indicates that the present S(2)((1)B(2u)) state calculated in the adiabatic representation effectively includes contribution from the diabatic vibronic coupling through the conical intersection. (C) 2009 Elsevier B.V. All rights reserved.
Ab initio studies of excited electronic state S-2 of pyrazine and Franck-Condon simulation of its absorption spectrum
(2009-07-07)
He, Rongxing
;
Zhu, Chaoyuan
;
Chin, Chih-Hao
;
Lin, Sheng Hsien
;
應用化學系分子科學碩博班
The equilibrium geometry and 24 vibrational-normal-mode frequencies of the excited state S-2(B-1(2u))of pyrazine are calculated and characterized using the complete active space self-consistent field method in the adiabatic representation. The displaced harmonic oscillator approximation is used to simulate the absorption spectrum of the S-2(B-1(2u)) state along with the Franck-Condon approximation. It is found that the totally symmetric mode v(1) plays the most important role and this exactly agrees with the experimental observations. The simulated absorption spectrum agrees well with those experimentally observed. This indicates that the present S-2(B-1(2u)) state calculated in the adiabatic representation effectively includes contribution from the diabatic vibronic coupling through the conical intersection. (C) 2009 Elsevier B.V. All rights reserved.
Effects of polydispersity index and molecular weight on crystallization kinetics of syndiotactic polystyrene (sPS)
(2009-07-08)
Chen, Chen-Ming
;
Hsieh, Tsung-Eong
;
Ju, Ming-Yih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Isothermal crystallization kinetics of syndiotactic polystyrene (sPS) is reported in this work with Avrami analytical method. it was found that the spherulite growth rate and overall crystallization rate depend on the crystallization temperatures, average molecular weight ((M) over bar (W)) and polydispersity index (PDI). The experimental results for the melt and cold crystallization processes of sPS revealed that the PDI and (M) over bar (W) exhibit pivotal effects on the crystallization rate, which increases with the decrease of (M) over bar (W) and PDI. (C) 2009 Elsevier B.V. All rights reserved.
Comparative Investigation of Ultrafast Photoinduced Processes in Salicylidene-Aminopyridine in Solution and Solid State
(2009-07-09)
Sliwa, Michel
;
Mouton, Nicolas
;
Ruckebusch, Cyril
;
Aloise, Stephane
;
Poizat, Olivier
Photodynamics and excited-state intramolecular proton transfer (ESIPT) of N-(3,5-ditert-butylsalicylidene)-4-aminopyridine (4P) and N-(3,5-ditert-butylsalicylidene)-2-aminopyridine (2P) are studied by steady-state and transient optical spectroscopy in solution and solid state (microcrystalline powder). These two compounds are representative of anils Classes A and B, respectively. The results confirm that in solution both compounds have a similar dynamic behavior: upon excitation at 390 nm, ESIPT leads to different cis-keto* fluorescent species which relax to the photochromic trans-keto photoproduct within a few tens of picoseconds. Furthermore, for the first time, picosecond data are recorded for the two classes of anils in the solid state: in 2P, two cis-keto* fluorescent excited state species (23 and 250 ps lifetime) are relaxing exclusively to the cis-keto ground state, whereas in 4P, a single cis-keto* fluorescent species is observed which leads to the trans-keto photoproduct in 250 ps via an intermediate metastable species.