Browsing by Issue Date, starting with "2009-05-11"

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Organic Base Modulation Triodes and Their Inverters on Flexible Substrates
(2009-05-11)
Cheng, Shiau-Shin
;
Chuang, You-Che
;
Kekuda, Dhananjay
;
Ou, Chun-Wei
;
Wu, Meng-Chyi
Organic base modulation triodes (OBMTs) are fabricated using two back-to-back Schottky diodes and deposited on a flexible substrate. With the advantage of the shorter channel, the OBMTs can be operated under lower voltages and faster frequencies. The inverter is fabricated using the OBMT connected with a resistor in series.
具3D聲場效果之陣列式助聽器
(2009-05-11)
白明憲
;
林振邦
本發明係一種具3D聲場效果之陣列式助聽器,其係以陣列式麥克風接收至少一聲源訊號並輸出至數位訊號處理器,數位訊號處理器依據聲源訊號進行程序建立聲束及掃描該聲源訊號之方向,陣列訊號處理方法包含超指向性法(super directive method)及延遲加成法(delay and sum method),利用陣列訊號處理方法進行方向估計及聲束形成,係利用超指向性法提高聲源指向性與訊號對聲源之雜訊比以得到最大聲源訊號,利用延遲加成法進行方向估計以找出聲源方向,搭配頻率補償系統及頭部轉移函數以產生3D聲場效果。
Mixed-voltage input/output buffer
(2009-05-12)
Ker
;
Ming-Dou
;
Hu
;
Fang-Ling
A mixed-voltage I/O buffer comprises an input circuit, an output circuit, an I/O pad, a pre-driver circuit coupled to the output circuit, two added coupled N-type transistors, and a dynamical gate-controlled circuit coupled to each gate of the two N-type transistors and the pre-driver circuit; one of the N-type transistors is coupled to the input circuit and the output circuit; the other N-type transistor and the dynamic gate-controlled circuit are together coupled to the I/O pad. Thereby, a mixed-voltage I/O buffer which receives 2×VDD-tolerant input signals and overcomes the hot-carrier degradation is realized.
Miniature inductor suitable for integrated circuits
(2009-05-12)
Kuo
;
Chien-Nan
;
Ma
;
Chien-Chia
A miniature inductor suitable for integrated circuits comprises a semiconductor substrate having a coplanar strip line and a plurality of metal-insulator-metal (MIM) capacitors, wherein the plurality of MIM capacitors are connected between the transmission lines of the coplanar strip line in parallel, and the coplanar strip line connected with the MIM capacitors further comprises a crossed planar strip line structure or a shifted planar strip line structure. The present invention reduces the occupied area for an inductor by adding the MIM capacitors and folding the transmission lines, and alleviates the quality factor degradation of the inductor caused by substrate loss.
Mixed voltage input/output buffer having low-voltage design
(2009-05-12)
Ker
;
Ming-Dou
;
Chen
;
Shih-Lun
A mixed-voltage input/output buffer having low-voltage design comprises a pre-driver, a tracking unit, a driving unit, and input/output pad, a floating-well unit and a transporting unit. The pre-driver receives first data signal and enable signal and outputs first and second data voltages. The tracking unit provides Gate-Tracking function. The driving unit couples the pre-driver and the tracking unit for production of a first buffer voltage corresponding to the first data voltage. The input/output pad couples the driving unit to output a first buffer voltage and to receive a second data signal. The output unit is used for outputting a second buffer voltage corresponding to the second data signal. The floating-well unit couples to the driving unit and the input/output pad in order to output first buffer voltage and receive second data signal. The floating-well unit is used for preventing leakage current.
Electronic structure of pyrochlore Cd2Re2O7
(2009-05-13)
Huang, Shih-Wen
;
Jeng, Horng-Tay
;
Lin, J-Y
;
Chang, W. J.
;
Chen, J. M.
Detailed band structure calculations have been performed for Cd2Re2O7 in high-, middle- and low-temperature (T) phases. The calculations are based on the observed lattice structures from x-ray diffraction measurements. The spin-orbit interaction is incorporated self-consistently in both the generalized gradient approximation (GGA) and the GGA plus Hubbard U (GGA + U) approaches. It is found that the on-site U has negligible effects on the Re 5d band structures; therefore both the GGA and GGA + U Re 5d band energies agree well with the observed O K-edge x-ray absorption spectroscopy (XAS) spectrum, whereas the Cd 4d band energy observed from photoemission spectroscopy can only be correctly reproduced by GGA + U calculations, indicating the relatively itinerant Re 5d and localized Cd 4d electrons. On the other hand, the spin-orbit coupling gives rise to nontrivial spin and orbital magnetic moments for the middle-T phase. Most unexpectedly, we found that the low-T phase exhibits quasi-two-dimensional Fermi surfaces. The calculated carrier numbers for the three phases are, at least qualitatively, consistent with the measured Hall coefficient.
Electronic structure of pyrochlore Cd(2)Re(2)O(7)
(2009-05-13)
Huang, Shih-Wen
;
Jeng, Horng-Tay
;
Lin, J-Y
;
Chang, W. J.
;
Chen, J. M.
Detailed band structure calculations have been performed for Cd(2)Re(2)O(7) in high-, middle- and low-temperature (T) phases. The calculations are based on the observed lattice structures from x-ray diffraction measurements. The spin-orbit interaction is incorporated self-consistently in both the generalized gradient approximation (GGA) and the GGA plus Hubbard U (GGA + U) approaches. It is found that the on-site U has negligible effects on the Re 5d band structures; therefore both the GGA and GGA + U Re 5d band energies agree well with the observed O K-edge x-ray absorption spectroscopy (XAS) spectrum, whereas the Cd 4d band energy observed from photoemission spectroscopy can only be correctly reproduced by GGA + U calculations, indicating the relatively itinerant Re 5d and localized Cd 4d electrons. On the other hand, the spin-orbit coupling gives rise to nontrivial spin and orbital magnetic moments for the middle-T phase. Most unexpectedly, we found that the low-T phase exhibits quasi-two-dimensional Fermi surfaces. The calculated carrier numbers for the three phases are, at least qualitatively, consistent with the measured Hall coefficient.
A Computational Study on the Adsorption Configurations and Reactions of Phosphorous Acid on TiO2 Anatase (101) and Rutile (110) Surfaces
(2009-05-14)
Raghunath, P.
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
We report the result of a density functional theory study on the adsorption and decomposition pathways of phosphorous acid (H3PO3) on TiO2 anatase (101) and rutile (110) surfaces. The most stable adsorption structure for H3PO3 and its isomer, HP(O)(OH)(2), is a monodentate adsorption mode for the anatase surface with calculated adsorption energies 23.5 and 38.5 kcal/mol and a bidentate adsorption mode for rutile surface with 26.7 and 36.6 kcal/mol. The mechanisms for the surface reactions of these species have been explicitly elucidated with the computed potential energy surfaces. The barriers for the stepwise H3PO3 H-migration to two nearby bridged O atoms reactions on anatase leads to Ti-OP(OH)O-Ti(a) + 2H-O-b(a) with 7.9 and 6.8 kcal/mol barriers. Even lower activation barriers (1.3 and 2.9 kcal/mol) have been obtained on the rutile (110) surface for the same bond breaking modes. The intermediate Ti-OP(OH)O-Ti(a) thus formed on both surfaces can further decompose via two distinct pathways through H-migration to the P atom and H2O elimination to produce Ti-OP(H)(O)O-Ti(a) and Ti-OPO-Ti(a), respectively. In addition, we have calculated the adsorption and reactions of the dimer of H3PO3 on both surfaces. The most noticeable difference occurs in the energy levels of the H3PO3 reactions on the anatase and rutile surfaces, with the rutile being more reactive than the anatase surface. The predicted adsorption energies show that Ti-OP(OH)O-Ti(a) with two hydrogen atoms on bridged surface oxygen atoms is 47.1 kcal/mol for anatase and 42.4 kcal/mol for rutile; both are low when compared with the Ti-OB(OH)O-Ti(a) on the same surfaces, 140.1 and 134.6 kcal/mol, respectively. Our density of states analysis shows that OB(OH)O has a larger overlap with the TiO2 surface than OP(OH)O has, favoring the former's charge transfer efficiency.
Holographic information recording and reproducing apparatus for the same
(2009-05-14)
Hsieh, Mei-Li
;
Lin, Shiuan-Huei
;
Wang, Jui-Hsin
;
Hsu, Ken-Yuh
;
Chiang, Don-Yau
In a holographic information recording and reproducing apparatus, an optical fiber guides a reference beam toward a recording medium for holographic recording, and a precision rotator is turned, so that the reference beam is incident on the recording medium at different angles and interferes with a data-carrying signal beam to complete the recording of holographic information on the recording medium. To reproduce the holographic information, the optical fiber guides a reading beam, and the reading beam is incident on the recording medium at an angle the same as the reference beam for the recording to reproduce the holographic information stored on the recording medium. With the optical fiber and the precision rotator, a simplified light path system and a wide range of incident angles for the reference and reading beams may be achieved, and the transmissive, reflective, and 90-degree holographic storage techniques may be integrated in one single apparatus.
THREE-DIMENSIONAL MICROPROBE ARRAY
(2009-05-14)
Chiou, Jin-Chern
;
Chang, Chih-Wei
The present invention discloses a three-dimensional microprobe array assembly structure, wherein spacers are used in assembling edge-type microprobe arrays to form a three-dimensional structure, and the spacers reveal conductive pads of the edge-type microprobe arrays to benefit wire bonding. The present invention detects depths and angles and thus increases detection reliability. Besides, in the present invention, the related IC is integrated with the spacer to achieve circuit integration and reduce cost.
A Computational Study on the Adsorption Configurations and Reactions of Phosphorous Acid on TiO(2) Anatase (101) and Rutile (110) Surfaces
(2009-05-14)
Raghunath, P.
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
We report the result of a density functional theory study on the adsorption and decomposition pathways of phosphorous acid (H(3)PO(3)) on TiO(2) anatase (101) and rutile (110) surfaces. The most stable adsorption structure for H(3)PO(3) and its isomer, HP(O)(OH)(2), is a monodentate adsorption mode for the anatase surface with calculated adsorption energies 23.5 and 38.5 kcal/mol and a bidentate adsorption mode for rutile surface with 26.7 and 36.6 kcal/mol. The mechanisms for the surface reactions of these species have been explicitly elucidated with the computed potential energy surfaces. The barriers for the stepwise H(3)PO(3) H-migration to two nearby bridged O atoms reactions on anatase leads to Ti-OP(OH)O-Ti(a) + 2H-O(b)(a) with 7.9 and 6.8 kcal/mol barriers. Even lower activation barriers (1.3 and 2.9 kcal/mol) have been obtained on the rutile (110) surface for the same bond breaking modes. The intermediate Ti-OP(OH)O-Ti(a) thus formed on both surfaces can further decompose via two distinct pathways through H-migration to the P atom and H(2)O elimination to produce Ti-OP(H)(O)O-Ti(a) and Ti-OPO-Ti(a), respectively. In addition, we have calculated the adsorption and reactions of the dimer of H(3)PO(3) on both surfaces. The most noticeable difference occurs in the energy levels of the H(3)PO(3) reactions on the anatase and rutile surfaces, with the rutile being more reactive than the anatase surface. The predicted adsorption energies show that Ti-OP(OH)O-Ti(a) with two hydrogen atoms on bridged surface oxygen atoms is 47.1 kcal/mol for anatase and 42.4 kcal/mol for rutile; both are low when compared with the Ti-OB(OH)O-Ti(a) on the same surfaces, 140.1 and 134.6 kcal/mol, respectively. Our density of states analysis shows that OB(OH)O has a larger overlap with the TiO(2) surface than OP(OH)O has, favoring the former's charge transfer efficiency.
Equiangular-spiral bent lightpipes with arbitrary bent angle
(2009-05-15)
Chu, Shu-Chun
;
Cheng, Yi-Kai
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
A recent study proposed the concept of a leakage-free bent lightpipe with an equiangular-spiral shape [S.-C. Chu, J.-L Chern, Opt. Lett. 30 (2005) 3006]. This paper extends the design of a leakage-free equiangular-spiral bent lightpipe with arbitrary-bend-angle and addresses in detail the mathematical formalism required to build such an equiangular-spiral bent lightpipe. Furthermore, a comparison of the proposed equiangular-spiral bent lightpipe and a conventional circular bent lightpipe is provided. Numerical verifications are discussed, and experimental explorations with different bent shapes and angles are carried out for comparison. Results show that equiangular-spiral bent lightpipes with different bent angles exhibit a theoretical 100% transmission with more than 76% efficiency when practically propagating, which is much better than conventional circular bent lightpipes. The output irradiance distributions of bent lightpipes with different bent shapes are also investigated. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
Removal of Hg(2+) from Aqueous Solution Using a Novel Composite Carbon Adsorbent
(2009-05-15)
Chang, Yu-Hsin
;
Hsieh, Kuo-Huang
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
A novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin-crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg(2+)) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the Uptake equilibrium and kinetics, of Hg(2+) ions by the GCA. The Hg(2+) adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg(2+) adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg(2+) increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg(2+) adsorption capacity and rate than activated carbon, which might he caused by the incorporation of chitosan into the GCA. The maximum Hg(2+) adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg(2+) ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg(2+) removal at low pH values. The Hg(2+) absorbed beads of the GCA can be effectivelY regenerated and reused using H(2)SO(4). (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2445-2454, 2009
Removal of Hg2+ from Aqueous Solution Using a Novel Composite Carbon Adsorbent
(2009-05-15)
Chang, Yu-Hsin
;
Hsieh, Kuo-Huang
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
A novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin-crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg2+) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the Uptake equilibrium and kinetics, of Hg2+ ions by the GCA. The Hg2+ adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg2+ adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg2+ increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg2+ adsorption capacity and rate than activated carbon, which might he caused by the incorporation of chitosan into the GCA. The maximum Hg2+ adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg2+ ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg2+ removal at low pH values. The Hg2+ absorbed beads of the GCA can be effectivelY regenerated and reused using H2SO4. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2445-2454, 2009
Theoretical and Experimental Investigations of Direct-Detected RF-Tone-Assisted Optical OFDM Systems
(2009-05-15)
Peng, Wei-Ren
;
Wu, Xiaoxia
;
Arbab, Vahid R.
;
Feng, Kai-Ming
;
Shamee, Bishara
In this paper, we propose and experimentally demonstrate a radio frequency (RF)-tone-assisted optical orthogonal frequency-division multiplexing (OFDM) transmission. By inserting an RF tone at the edge of the signal band and biasing the Mach-Zehnder modulator (MZM) at the null point, the proposed system has a better sensitivity and chromatic dispersion (CD) tolerance compared to the previous intensity-modulated single-sideband OFDM (SSB-OFDM). We show analytically that the majority of the linear channel impairments, such as the transmitter, CD, optical filtering, and receiver, can be compensated for by a simple zero-forcing equalizer. Besides, the optimum value of the important parameter, carrier-to-signal-power ratio (CSPR), is analytically obtained and supported via the experimental results. We also observe that the relatively worse sensitivity of the previous SSB-OFDM can be attributed to the limited CSPR. We experimentally demonstrate a 10-Gb/s, 8 quadrature-amplitude modulation (QAM) RF-tone-assisted OFDM transmission, and show that our system has a similar to 5-dB better sensitivity compared to the previous intensity-modulated SSB-OFDM and exhibits a negligible transmission penalty after 260-km uncompensated standard single-mode fiber (SSMF).
Electrochemical reduction of CO2 by Cu2O-catalyzed carbon clothes
(2009-05-15)
Chang, Tin-Yu
;
Liang, Ru-Meng
;
Wu, Pu-Wei
;
Chen, Jing-Yu
;
Hsieh, Yu-Chi
Cu2O cubes with average edge lengths of 640 nm were prepared by a chemical reduction approach. The as-synthesized Cu2O particles were deposited on carbon clothes for electrochemical characterizations in cyclic voltammetry (CV) and potentiostatic measurements. In 0.5 M NaOH electrolytes saturated with N-2 or CO2, both the Cu2O and carbon clothes were stable at the potential range of 0 to -1.7 V. Comparisons in the Current responses from the CV and potentiostatic measurements suggested the Cu2O with notable catalytic abilities for the CO2 reduction. The mass activity was estimated at 0.94 mA/mg. Chemical analysis from gas chromatography confirmed the methanol to be the predominant product. (C) 2009 Elsevier B.V. All rights reserved.
Analysis of GaAs/GaSb/GaAs structures under optical excitation considering surface states as an electron reservoir
(2009-05-15)
Hsieh, Hong-Wen
;
Yen, Shun-Tung
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We present a self-consistent model for the analysis of the carrier distribution, the band profile, and the transition energy of type-II aligned GaAs/GaSb/GaAs structures under optical excitation. The model considers the surface states as an electron reservoir, associated with pinning of the conduction band Fermi level at the midgap. In our model, the optical generated holes in the GaSb quantum well causes a potential well on one side of the GaSb layer, which can efficiently accommodate the optically generated electrons. Accordingly, we derive a relation connecting the excitation power to the carrier density. Using the relation and the effective triangular potential approximation, we obtain a simple formula for the transition energy shift as a function of the excitation power, which follows the cube-root rule quite well. The calculation allows the determination of the band offset of a type-II heterointerface by comparison with data from photoluminescence measurement. The result suggests the unstrained valence band offset of GaSb/GaAs to lie between 0.5 and 0.55 eV. We also present a simplified model for analyzing the electronic and optical properties of type-II heterostructures without the need of a self-consistent calculation.
Estimation of the Bit Error Rate for Direct-Detected OFDM Signals With Optically Preamplified Receivers
(2009-05-15)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Willner, Alan E.
;
Chi, Sien
;
光電工程學系
In this paper, we provide a numerical bit error rate (BER) estimation approach for direct-detected orthogonal frequency division multiplexing (OFDM) signals in the presence of optical preamplified receivers. The individual BER of each subcarrier is first computed by considering their electrical signal-to-noise ratio (SNR), and then the ensemble BER is derived simply by taking the average of all the subcarriers' BERs. The calculated BER is verified by the conventional error-counting approach with high precision and is still accurate with higher quadratic-amplitude modulation (QAM) formats, even under the influences of the optical filtering and polarization mode dispersion (PMD) effects. Based on our simulation approach, the required extra power budget for 16- and 64-QAM relative to 4-QAM format are found to be similar to 3.8 and 8.2 dB, respectively, at a BER of 10(-9) Furthermore, we use this approach to compare the receiving sensitivities and PMD tolerances for the previous proposed gapped and interleaved radio-frequency (RF)-tone-assisted OFDM systems. The results show that the gapped OFDM has a better sensitivity while the interleaved OFDM has a more PMD-tolerable capability.
Electrochemical reduction of CO(2) by Cu(2)O-catalyzed carbon clothes
(2009-05-15)
Chang, Tin-Yu
;
Liang, Ru-Meng
;
Wu, Pu-Wei
;
Chen, Jing-Yu
;
Hsieh, Yu-Chi
Cu(2)O cubes with average edge lengths of 640 nm were prepared by a chemical reduction approach. The as-synthesized Cu(2)O particles were deposited on carbon clothes for electrochemical characterizations in cyclic voltammetry (CV) and potentiostatic measurements. In 0.5 M NaOH electrolytes saturated with N(2) or CO(2), both the Cu(2)O and carbon clothes were stable at the potential range of 0 to -1.7 V. Comparisons in the Current responses from the CV and potentiostatic measurements suggested the Cu(2)O with notable catalytic abilities for the CO(2) reduction. The mass activity was estimated at 0.94 mA/mg. Chemical analysis from gas chromatography confirmed the methanol to be the predominant product. (C) 2009 Elsevier B.V. All rights reserved.
色序顯示器之色彩資料處理裝置及其方法
(2009-05-16)
黃乙白
;
孫沛立
;
林芳正
;
魏景明
;
謝漢萍
本發明係為一種色序顯示器之色彩資料處理裝置及其方法,本發明之色彩資料處理裝置及其方法配合具有紅光、綠光、藍光及由紅光、綠光或藍光混和之色光等四種背光之色序顯示器,利用該色彩資料處理裝置及其方法處理一色彩資料,得到分別對應四種背光之灰階値,該些灰階値配合該色序顯示器所顯示出之畫面可大幅降低色分離現象,更不會使該畫面失真。