Browsing by Issue Date, starting with "2005-10-03"

Now showing 1 - 20 of 65876

Intracavity measurement of liquid crystal layer thickness by wavelength tuning of an external cavity laser diode
(2005-10-03)
Lan, YP
;
Lin, YF
;
Li, YT
;
Pan, RP
;
Lee, CK
The gap of a planar-aligned liquid crystal (LC) cell is measured by a novel method: Monitoring the change in output wavelength of an external-cavity diode laser by varying the voltage driving the LC cell placed in the laser cavity. This method is particularly suitable for measurement of LC cells of small phase retardation. Measurement errors of +/- 0.5 % and +/- 0.6 % for 9.6-mu m and 4.25-mu m cells with phase retardations of 1.63 mu m and 0.20 mu m respectively are demonstrated. (c) 2005 Optical Society of America.
Solving all 4-point correlation functions for bosonic open string theory in the high-energy limit
(2005-10-03)
Chan, CT
;
Ho, PM
;
Lee, JC
;
Teraguchi, S
;
Yang, Y
We study the implication of decoupling zero-norm states in the high-energy limit, for the 26-dimensional bosonic open string theory. Infinitely many linear relations among 4-point functions are derived algebraically, and their unique solution is found. Equivalent results are also obtained by taking the high-energy limit of Virasoro constraints, and as an independent check, we compute all 4-point functions of 3 tachyons and an arbitrary massive state by saddle-point approximation. (c) 2005 Elsevier B.V. All rights reserved.
Mobility enhancement of polycrystalline-Si thin-film transistors using nanowire channels by pattern-dependent metal-induced lateral crystallization
(2005-10-03)
Wu, YC
;
Chang, TC
;
Liu, PT
;
Wu, YC
;
Chou, CW
This work presents a method for enhancing the mobility of polycrystalline-Si (poly-Si) thin-film transistors (TFTs) by pattern-dependent metal-induced-lateral-crystallization (PDMILC) using nanowire channels. Experimental results indicate that the field-effect mobility of PDMILC TFT was enhanced as the channel width decreased, because the lateral length of the poly-Si grains increased. The PDMILC poly-Si TFT with ten nanowire channels (M10) had the greatest field-effect mobility, 109.34 cm(2)/V s and the lowest subthreshold swing, 0.23 V/dec, at a gate length of 2 mu m. The field-effect mobility also increased as the gate length in the M10 PDMILC poly-Si TFT device declined, because the number of poly-Si grain-boundary defects was reduced. (C) 2005 American Institute of Physics.
Strain relaxation in InAs/InGaAs quantum dots investigated by photoluminescence and capacitance-voltage profiling
(2005-10-03)
Chen, JF
;
Hsiao, RS
;
Chen, YP
;
Wang, JS
;
Chi, JY
We present detailed studies of the onset of strain relaxation in InAs/InGaAs quantum dots. We show that the ground-state photoluminescence (PL) emission redshifts with increasing the InAs coverage before relaxation and blueshifts when relaxation occurs. PL spectra of the relaxed samples show two predominant families of dots with very different temperature-dependent efficiency. By comparison we show that the dots emitting at long wavelength are degraded by relaxation while the dots emitting at short wavelength remain coherently strained. Consequently, the PL spectra are dominated by the dots emitting at short wavelength, leading to the observed blueshift. This result suggests that the relaxation does not occur uniformly. In addition, we show that the relaxation occurs in the dot bottom interface. (C) 2005 American Institute of Physics.
紅
(2005-10-05)
管管
Enhanced resonant Raman scattering and electron-phonon coupling from self-assembled secondary ZnO nanoparticles
(2005-10-06)
Cheng, HM
;
Lin, KF
;
Hsu, HC
;
Lin, CJ
;
Lin, LJ
Self-assembled secondary ZnO nanoparticles, recognized with the agglomeration of crystalline subcrystals, are successfully synthesized by a simple sol-gel method. TEM images display that one artificial cluster behaves in a single-crystal-like wurtzite structure because subcrystals coagulate as the same crystal orientation. Moreover, from the resonant Raman scattering, the as-grown sample exhibits phonon red shift; meanwhile, the coupling strength between electron and longitudinal optical phonon, determined by the ratio of second to first-order Raman scattering cross sections, diminishes compared with the samples after postannealing at 350 and 500 degrees C. The size dependence of electron-phonon coupling is principally as a result of the Frohlich interaction.
Efficient method and apparatus for convolution of input signals
(2005-10-06)
Liu, Chi-Min
;
Lee, Win-Chieh
;
Yang, Chung-Han
An FIR-based apparatus performs fast convolution in the frequency domain for generating room reverberation. The impulse response of a room is segmented and transformed by FFT to form a plurality of segmented room frequency spectra. The input signal to the room is also segmented and transformed to form segmented input frequency spectra. Either overlap-and-add method or overlap-and-save method is applied in the apparatus to accomplish the fast convolution based on the multiplication of segmented input frequency spectrum and segmented room frequency spectrum. To further reduce the complexity of the convolution, a segmented room frequency spectrum is processed to remove high frequency components before being used in the fast convolution according to a perceptual criterion.
Electronic transport properties of alpha-TiAl alloys
(2005-10-10)
Zhang, DL
;
Liu, SM
;
Jing, XN
;
Luo, JL
;
Zhang, XG
The electrical resistivity, thermal conductivity, and thermopower of alpha-TiAl alloy samples with A1 content from 0 at.% to 10 at.% are measured from room temperature down to liquid helium temperature. It is found that with the increase in A1 content the single phonon scattering contribution to the resistivity remains nearly constant, but the multiphonon scattering contribution monotonously increases. This provides an alternative explanation of resistivity saturation to the shunt-resistor model. The Wiedemann-Ranz law holds for the whole temperature range, allowing the separation of the electron and phonon contributions to the thermal conductivity. The data from samples with different doping levels enable us to separate the band and the scattering terms in the thermopower.
間諜魚
(2005-10-10)
管管
Method for calculating syndrome polynomial in decoding error correction codes
(2005-10-11)
Lee
;
Chen-Yi
;
Chang
;
Hsie-Chia
;
Lin
The present invention provides a method of calculating the syndrome polynomial in decoding error correction codes. From the relation between the syndromes and the coefficients of the error locator polynomial, the inference that the first t syndromes are zeros, then the next t syndromes are also zeros can be deduced, wherein t is the largest number of correctable errors. For all received codewords, the first t syndromes are calculated. Next, whether the first t syndromes are zeros is judged. If the first t syndromes are zeros, the computation is stopped; otherwise, the next t syndromes are calculated. Therefore, the present invention can judge whether the received codeword is erroneous with only a half of computation, hence effectively reducing the computation in practical operation and achieving the object of low power consumption.
Compact 3D-MEMS-meander rnonopole antenna
(2005-10-13)
Huang, CU
;
Chen, IY
;
Chen, HJH
;
Jou, CF
;
Huang, SRS
A MEMS meander monopole antenna is fabricated in the form of a folded microstrip on the upper and bottom surfaces of the substrate. This design is based on the meander line principle with a three-dimensional structure to achieve reduced size compared to many other small size printed antennas. The MEMS technologies, such as excimer laser drilling and copper electroplating were used in the fabrication of this antenna. This antenna can be mounted on the silicon wafer by anodic bonding technology. The design features 2.45 GHz operating frequency with 190 MHz bandwidth for WLAN applications. The geometric length of the antenna is 21 mm, and the width is 4 mm. Measured results have good agreement with simulation data.
Fast bit allocation method for audio coding
(2005-10-13)
Yang, Cheng-Han
;
Hang, Hsueh-Ming
A fast bit allocation algorithm for audio coding is disclosed. A virtual Huffman codebook model is referred in a trellis-based optimization approach to obtain a set of optimized scale factors, and then the set of optimized scale factors is referred in a trellis-based optimization approach to obtain a set of optimized Huffman codebooks. Therefore, the present invention can significantly reduce the amount of computation for the bit allocation. Further, according to the experimental data, the present invention can keep almost the same compression efficiency as the prior art JTB optimization. Hence, the present invention is more suitable for practical applications.
Effect of electron-phonon scattering on shot noise in nanoscale junctions
(2005-10-14)
Chen, YC
;
Di Ventra, M
;
電子物理學系
;
Department of Electrophysics
We investigate the effect of electron-phonon inelastic scattering on shot noise in nanoscale junctions in the regime of quasiballistic transport. We predict that when the local thermal energy of the junction is larger than its lowest vibrational mode energy eV(c), the inelastic contribution to shot noise ( conductance) increases ( decreases) with bias as V(root V) The corresponding Fano factor thus increases as root V. We also show that the inelastic contribution to the Fano factor saturates with increasing thermal current exchanged between the junction and the bulk electrodes to a value which, for V >> V-c, is independent of bias. These predictions can be readily tested experimentally.
A novel hybrid model for portfolio selection
(2005-10-15)
Ong, CS
;
Huang, HJ
;
Tzeng, GH
;
科技管理研究所
;
Institute of Management of Technology
As we know, the performance of the mean-variance approach depends on the accurate forecast of the return rate. However, the conventional method (e.g. arithmetic mean or regression-based method) usually cannot obtain a satisfied solution especially under the small sample situation. In this paper, the proposed method which incorporates the grey and possibilistic regression models formulates the novel portfolio selection model. In order to solve the multi-objective quadric programming problem, multi-objective evolution algorithms (MOEA) is employed. A numerical example is also illustrated to show the procedures of the proposed method. On the basis of the numerical results, we can conclude that the proposed method can provide the more flexible and accurate results. (c) 2004 Elsevier Inc. All rights reserved.
靜電放電防護電路
(2005-10-16)
柯明道
;
陳穩義
本發明係一種靜電放電防護電路，其應用於具有高低壓混合介面之電路上，本發明利用閘極耦合技術來達到靜電放電防護效果，當靜電發生於輸入／輸出銲墊時，一電容會耦合靜電電壓，並分別經由一第一二極體與一第二二極體，來提高一疊接NMOS之上層與下層NMOS的閘極電位，藉此讓上層與下層NMOS產生通道，以幫助靜電更有效透過該疊接NMOS而導通至地。本發明在具有疊接NMOS架構之高低壓混合介面電路上設置觸發電路，以利用閘極耦合技術觸發導通該疊接NMOS，藉此增進疊接NMOS之靜電放電防護能力，並改善習知靜電放電防護電路無法直接套用於疊接NMOS結構或需外加極大保護元件等缺失。
用於音訊編碼之快速位元分配法
(2005-10-16)
楊政翰
;
杭學鳴
一種用於音訊編碼之快速位元分配法，係在使用虛擬霍夫曼編碼書模型的條件下，先行利用籬柵圖方法對比例因子參數作最佳化，得到一組最佳的比例因子參數。之後，再使用前述獲得之最佳的比例因子參數，利用籬柵圖方法對霍夫曼編碼書參數作最佳化，得到一組最佳的霍夫曼編碼書參數。因此，可在維持近似於習知方法之壓縮效能的情況下，大幅降低位元分配所需之運算量，以利於實際應用之執行。
利用服務網域的佈署資訊進行快速網域交遞之方法
(2005-10-16)
曾建超
;
張弘鑫
;
謝明燈
本發明提供一種利用服務網域內之代理器以及網路存取點的部署資訊進行快速網域交遞之方法，其係根據該服務網域的部署資訊得知代理器以及代理器所管轄之網路存取點的位置，根據此網域部署資訊，當一行動節點與其中一服務代理器所管轄的網路存取點溝通時，行動節點可預先向鄰近代理器取得網路資源，以備在進行代理器間之交遞前預先使用或在交遞後馬上使用該網路資源。因此本發明可達成快速交遞之功效，且提供流暢的服務。
使用週期性結構的矩形波導及其設計方法
(2005-10-16)
莊晴光
;
吳憲順
本發明係將傳統矩形波導之部份或全部的表面以週期性結構取代。不需要在波導內使用高介電常數之材料，也不需改變矩形波導的操作模態。僅利用週期性結構在低於能階止帶頻段下之擾動特性設計出相較於同尺寸之傳統矩形波導更低截止頻率之矩形波導；另一方面，利用週期性結構在能階止帶頻段中之高阻抗表面特性，實現出以TM10為主模之矩形波導。本發明亦有關於使用週期性結構的矩形波導的設計方法。
適用於超長指令字元之階層式指令編碼及其解碼器
(2005-10-16)
任建葳
;
林泰吉
;
張金祺
;
趙至敏
;
劉志尉
本發明提供一種適用於超長指令字元之階層式指令編碼方法及其對應之解碼器架構，編碼方法係將超長指令字元(VLIW)之各子指令依照需要轉換成長短不一之指令碼以縮短指令長度，接著將這些長度不固定的指令拆解成固定長度之頭及可變長度之尾欄位，最後加上控制資訊帽(cap)並依特有之排列方式置入一固定長度之指令包裹內，以方便程式記憶體之讀取及指令解碼。控制資訊帽中係包含一有效欄位來移除NOP指令，並同時解決一般可變長度VLIW需額外加入位置分配碼的問題；另外，本發明所特有之指令碼排列方式可採用對數移位器(logarithmic shifter)及漸進式移位器(incremental shifter)組成解碼器，具有簡易且高效率之優點。
利用嵌入式網路之機器人控制系統
(2005-10-16)
吳立偉
;
胡竹生
本發明有關一種利用嵌入式網路之機器人控制系統，其運用嵌入式網路技術以及即時網路協定整合機器人運算架構，使其達到更適合於網路環境系統，並同時擁有高傳輸率、高容錯性、高度系統整合能力、節省能源、及高強度的重複利用能力，其低成本分散式架構更提高了運算的效率及擁有即時通訊能力，並使得複雜的交錯協調控制容易，容易與叢集系統連結，因而降低研發人員的門檻，節省模擬開發成本。