Browsing by Issue Date, starting with "2000-12-12"

Now showing 1 - 20 of 77895

Conformational conversion and local packing of cyclic olefin copolymers
(2000-12-12)
Chu, PPJ
;
Cheng, MH
;
Huang, WJ
;
Chang, FC
;
應用化學系
Cyclic olefin copolymer (COC, poly(norbornene-co-ethylene)) catalyzed by ansa-ethylenebis-(indenyl)zirconium dichloride (Et[Ind](2)ZrCl2)/methylaluminoxane (MAO) gives rise to phenomenal increase of T-g upon annealing. Unaveraged solid-state C-13 NMR resonance of the CH carbons in the norbornene (53 and 49 ppm) evidenced the conformation conversion from T[X]T and G[M]G to more stable T[X]G conformers (where [X] = [T] or [G] represent the norbornene chain conformation). As the persistent length increases with the conversion, local packing of the rigid chain subsequently occurs. Synchrotron source X-ray diffraction provides clear evidence of the averaged interchain contraction from 12.0 to 8.5 Angstrom and a tighter distribution in the spacing after annealing. In the preannealed state, T-1p(H) relaxation time revealed both mobile (where conformer converts) and rigid components (where conformation is frozen), which coalesce into a further rigid component after extended annealing. The mechanisms governing the packing in amorphous COC are likely by the random chain diffusion and not from cooperative motion as described by the bundle-packing model.
管管作品三首
(2000-12-15)
管管
Single-longitudinal-mode operation of a grating-based fiber-ring laser using self-injection feedback
(2000-12-15)
Lee, CC
;
Chi, S
;
光電工程學系
;
Department of Photonics
A fiber Bragg grating- (FBG-) based fiber-ring laser that utilizes the transmitted light; of the FBG as self-injection feedback for single-longitudinal-mode (SLM) oscillation is proposed and demonstrated. This laser is simply constructed by means of feeding back the transmitted light of the FBG and is coupled into the main ring cavity through an optical coupler. The self-injection feedback is the key to ensuring SLM laser oscillation. The SLM operation principle is discussed in detail, and a SLM laser with output power of 6.6 dBm, an optical signal-to-noise ratio of 57 dB at 1549.19 nn, and a short-term linewidth of 3.5 kHz is reported. (C) 2000 Optical Society of America.
管管作品三首
(2000-12-15)
管管
Fourier and wavelet analyses of TOPEX/Poseidon-derived sea level anomaly over the South China Sea: A contribution to the South China Sea Monsoon Experiment
(2000-12-15)
Hwang, C
;
Chen, SA
;
土木工程學系
;
Department of Civil Engineering
We processed 5.6 years of TOPEX/Poseidon altimeter data and obtained time series of sea level anomaly (SLA) over the South China Sea (SCS). Fourier analysis shows that sea level variability of the SCS contains major components with periods larger than 180 days and is dominated by the annual and semiannual components. Tidal aliasing creates 30-180 day components that can be misinterpreted as wind-induced variabilities. Continuous and multiresolution wavelet analyses show that the SLA of the SCS has monthly to interannual components of time-varying amplitudes, and the regional slope of SLA is 8.9 mm yr(-1), which may be caused by the decadal climate change. Coherences of SLA with wind stress anomalies (WSA) and sea surface temperature anomalies (STA) are significant at the annual and semi-annual components. At periods of 2-5 years the wavelet coefficients of SLA, WSA, and STA have the same pattern, but WSA leads SLA, and STA follows SLA. The zero crossing of SLA in spring is highly correlated with the onset of the summer monsoon. The interannual variability of SLA is correlated with El Nino-Southern Oscillation, and most important is that when the El Nino-like wavelet coefficients of SLA over the warm pool northeast of Australia or the SCS change curvature from negative to positive, an El Nino is likely to develop. This is a contribution to the South China Sea Monsoon Experiment (SCSMEX).
管管作品三首
(2000-12-15)
管管
Low-temperature process to improve the leakage current of (Ba, Sr)TiO3 films on Pt/TiN/Ti/Si substrates
(2000-12-15)
Hwang, CC
;
Lai, MJ
;
Jaing, CC
;
Chen, JS
;
Huang, S
In this study, we employed an oxygen plasma post-treatment to improve the leakage characteristics of Pt/(Ba, Sr)TiO3(BST)/Pt capacitors prepared by the RF cosputtering technique. Applying oxygen plasma treatment to BST thin films can effectively passivate the oxygen vacancies of the BST films, thus decreasing the electric conduction paths of leakage current. The leakage current is reduced by as many as two orders of magnitude by this low-temperature (250 degreesC) and short duration (similar to5 min) process. However, the usage of oxygen plasma treatment is not unrestricted. Plasma treatment over a long time (more than 10 min) degrades the leakage characteristics, due to plasma damage. Therefore, a proper oxygen plasma treatment for as-deposited BST films is desired to improve leakage characteristics of BST thin films.
管管作品三首
(2000-12-15)
管管
藝文天空
(2000-12-17)
本報訊
台北詩歌節詩人朗誦
(2000-12-17)
馬岳琳
The energy spectrum of parabolic quantum dots
(2000-12-18)
Yang, CC
;
Huang, YS
;
電子物理學系
;
Department of Electrophysics
We calculate the energy spectrum of hydrogen impurity located in the center of parabolic quantum dot. The energy levels under this model differ from the previous results for the case of spherical quantum dot. The degeneracy of the energy levels is quite different as well. However, compared with the spherical quantum dot, the energy plateau under this model is not obvious. (C) 2000 Elsevier Science B.V. All rights reserved.
高強度鋼筋用於梁剪力筋之研究
(2001)
趙文成
;
國立交通大學土木工程學系
大學生跨領域科技能力培養研究計畫---培養大學生在生物科技與電機資訊跨領域科技能力之科技教育之研究(I)
(2001)
黃遠東
;
YANG-TUNGHUANG
;
國立交通大學電子工程學系
自主整合式W-CDWA基地台接收系統---子計畫I：W-CDMA基地台接收系統之架構與性能評估(III)
(2001)
蘇育德
;
SU YU TED
;
交通大學電信工程系
嘉南平原區域性地下水觀測站井佈置檢討
(2001)
張良正
;
Chang Liang-Cheng
;
國立交通大學防災工程研究中心
　　本計畫目標在配合嘉南平原及蘭陽平原新設觀測井所產生之水文地質資料，配合水文地質含水層分析及區域變數理論等較嚴謹的監測網規劃分析的方法，對嘉南平原、蘭陽平原及澎湖本島等地區進行地下水觀測站網站井位置、深度等之檢討並作出具體的建議。並為配合其他地震前後地下水位變化相關研究，於台南白河及新竹、苗栗地區新站井位置配合建議一至二口觀測井。
The state question in Chinese popular cultural studies
(Routledge, 2001)
J. Wang
38 GHz high-directivity planar leaky-mode antenna array
(2001)
Hung, TP
;
Tzuang, CKC
;
電信工程研究所
;
Institute of Communications Engineering
This paper resents a high-directivity planar microstrip antenna array operating at microwave frequency. The antenna array consists of 48 sub-arrays, and each sub-array comprises 4 elements. The radiation mechanism of the single element, by exciting the first higher order mode (EH, mode), can be estimated by the full-wave analysis. Through appropriately arranging and feeding these 192 single elements, the radiated characteristic of the antenna performs narrow radiation beamwidth both in azimuth (AZ) and elevation (EL), thus achieving high directivity. The planar microstrip antenna array prototype is built and tested at 38GHz by traditional printed circuit board (PCB) fabricating process. The measurement result indicates the high directivity of 22.3dB and the 3-dB beamwidth of 8degrees/12degrees (AZ/EL) at the elevated angle 30.2degrees away from the broadside direction.
介觀及無序金屬中電子相位破壞時間之量測(III)
(2001)
林志忠
;
LIN JUHN-JONG
;
國立交通大學物理研究所
Chemical modification of dicyclopentadiene-based epoxy resins to improve compatibility and thermal properties
(2001)
Hsiue, GH
;
Wei, HF
;
Shiao, SJ
;
Kuo, WJ
;
Sha, YA
A. series of siloxane-containing epoxy resins was obtained by curing dicyclopentadiene-containing epoxy DG with the silicon-containing curing agents TS, DS, and AS. Curing behavior was studied using DSC, and the activation energies of the DG curing reaction with curing agents TA, DS, and AS were found to be 59, 80, and 157 KJ/mol. Meanwhile, the curing reaction of DG with diamines was found to be a first-order reaction using Arrhenius plots. In addition, thermal stability and the weight loss behavior of the cured polymers were studied via TGA. The silicon-containing resins displayed higher weight loss temperatures and higher char yields than the silicon-free resin. The activation energies of degradation ranged from 108 to 206 KJ/mol. The morphology of the cured pieces were investigated using SEM. The DG/TS and DG/DS are more compatible between the epoxy and the curing agents than DG/AS. The limited oxygen index (LOI) values of 31 to 34 for the DG-based resin confirmed the effectiveness of silicon-containing epoxy resins as flame retardants. (C) 2001 Elsevier Science Ltd. All rights reserved.
A trustworthy Internet auction model with verifiable fairness
(2001)
Liao, GY
;
Hwang, JJ
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Describes a novel Internet auction model achieving verifiable fairness, a requirement aimed at enhancing the trust of bidders in auctioneers. Distrust in remote auctioneers prevents bidders from participating in Internet auctioning. According to proposed survey reports, this study presents four characteristics that render the Internet untrustworthy for bidders. These intrinsic properties suggest that auction sites not only follow auction policies, but provide customers with evidence validating that the policies are applied fairly. Evidence of verifiable fairness provides bidders with a basis for confidence in Internet auctions. Cryptographic techniques are also applied herein to establish a novel auction model with evidence to manifest and verify every step of the auctioneer. Analysis results demonstrate that the proposed model satisfies various requirements regarding fairness and privacy. Moreover, in the proposed model, the losing bids remain sealed.