Browsing by Issue Date, starting with "2005-01-06"

Now showing 1 - 20 of 67321

Polyimide and polyhedral oligomeric silsesquioxane nanocomposites for low-dielectric applications
(2005-01-06)
Lee, YJ
;
Huang, JM
;
Kuo, SW
;
Lu, JS
;
Chang, FC
A novel polyimide (PI) hybrid nanocomposite containing polyhedral oligomeric silsesquioxane (POSS) with well defined architecture has been prepared by copolymerization of octakis(glycidyldimethylsiloxy)octasilsesquioxane (Epoxy-POSS), 4,4'-oxydianiline diamine (ODA), and 4,4'-carbonyldiphthalic anhydride (BTDA). In these nanocomposite materials, the equivalent ratio of the Epoxy-POSS and ODA are adjustable, and the resultant PI-POSS nanocomposites give variable thermal and mechanical properties. More importantly, we intend to explore the possibility of incorporating POSS moiety through the Epoxy-POSS into the polyimide network to achieve the polyimide hybrid with lower dielectric constant (low-k) and thermal expansion. The lowest dielectric constant achieved of the POSS/PI material (PI-10P) is 2.65 by incorporating 10 wt% Epoxy-POSS (pure PI, k = 3.22). In addition, when contents of the POSS in the hybrids are 0, 3, 10 wt% (PI-0P, PI-3P, PI-10P), and the resultant thermal expansion coefficients (TEC) are 66.23, 63.28, and 58.25 ppm/degreesC, respectively. The reduction in the dielectric constants and the resultant thermal expansion coefficients of the PI-POSS hybrids can be explained in terms of creating silsesquioxane cores of the POSS and the free volume increase by the presence of the POSS-tethers network resulting in a loose PI structure. (C) 2004 Elsevier Ltd. All rights reserved.
Effects of over-roll thickness on cone surface roughness in shear spinning
(2005-01-10)
Chen, MD
;
Hsu, RQ
;
Fuh, KH
;
機械工程學系
;
Department of Mechanical Engineering
A high quality of cone surface finish was achieved by carefully controlled over-roll thickness in the shear spinning process. In this study, blank thickness, roller nose radius, mandrel revolution, roller feed and over-roll thickness were taken as major process variables to investigate the effects of the above parameters on the surface roughness of cone shape products. From the experiment, several sets of experimental data were obtained, which in turn were used to construct regression equations for applied forces and product surface roughness. The results were verified by four extra spinning experiments. It is found that deeper over-roll combines with the thinner blank sheet, larger roller nose radius and slower roller feed, and are advantageous for obtaining smoother surface roughness. Over-roll of the blank in shear spinning is an effective way to improve the surface roughness of the product. (C) 2003 Published by Elsevier B.V.
Optical birefringence and polarization dependent loss of square- and rectangular-lattice holey fibers with elliptical air holes: numerical analysis
(2005-01-10)
Liu, YC
;
Lai, Y
;
光電工程學系
;
Department of Photonics
Polarization dependent leakage loss as well as optical birefringence for the fundamental mode in square- and rectangular-lattice holey fibers with elliptical air holes are studied numerically based on the full-vector finite element method for the first time. It is shown that high birefringence in the order of 10(-2) and large polarization dependent loss required for single-polarization single-mode transmission are both achievable by using the proposed structure. (C) 2005 Optical Society of America.
Instruction pre-fetch amount control with reading amount register flag set based on pre-detection of conditional branch-select instruction
(2005-01-11)
Chen
;
Pao-Lung
;
Lee
;
Chen-Yi
An architecture of method for fetching microprocessor's instructions is provided to pre-fetch and pre-decode a next instruction. If the instruction pre-decoded is found a conditional branch instruction, an instruction reading-amount register is set for reading two instructions next to the current instruction in the program memory, or one is read instead if the next instruction is found an instruction other than the conditional branch one so as to waive reading of unnecessary program memory and thereby reduce power consumption.
深次微米級T型閘極半體裝置之製造方法
(2005-01-11)
張翼
;
張晃崇
;
傅國貴
次微米T形閘極技術是運用了I-line步進機以及相移光罩研發而成。由於這項技術具有成本低廉以及產能高等優點，對於砷化鎵單質微波積體電路的技術而言，非常具有競爭力。而在本發明中所描述的技術正是一種使用PSM技術製作出來的優秀T形閘極技術。首先，我們在晶片上鍍上一層2500A的氮化矽，並選擇8%半調相移光罩以及 I-line步進機進行曝光，製作出隔絕的窄溝結構。接下來運用反應離子蝕刻機進行乾式蝕刻製作出線寬小於0.25μ m的氧化矽窄溝，然後再將光阻去除。為了進一步縮小窄溝線寬，再將整片晶片鍍上一層500A的氮化矽後再使用反應離子蝕刻機蝕刻氮化矽，這個步驟可將窄溝的線寬縮小至0.2μm以下。最後塗佈一層光阻製作出T形閘極的結構後，再鍍上閘極金屬後進行撕開(lift-off)的製程，完成全部的閘極製程。和傳統砷化鎵單質微波積體電路製程比較，這種T形閘極的製程具有產能更高、成本更低等等的優點。
D類放大器（CLASS-D）之控制電路
(2005-01-11)
余祥華
;
胡竹生
本發明為一Class-D功率放大器的切換控制之信號調變及補償電路，藉以決定放大器輸出級的開關切換，使其輸出級導通電流的時間正比於信號大小，而避免能源的浪費與多餘的開關切換，以達到高效率與低雜訊的目的，此外，本發明具有補償及抑制控制頻寬內之失真及雜訊的能力，可大為提升Class-D放大器的效能及性能。
雞鳴寺經
(2005-01-12)
管管
Manufacturing method of thin film transistor
(2005-01-13)
Chang, Kow Ming
;
Chung, Yuan Hung
A method of manufacturing a thin film transistor for solving the drawbacks of the prior arts is disclosed. The method includes steps of providing an insulating substrate, sequentially forming a source/drain layer, a primary gate insulating layer, and a first conducting layer on the insulating substrate, etching the first conducting layer to form a primary gate; sequentially forming a secondary gate insulating layer and a second conducting layer on the primary gate; and etching the second conducting layer to form a first secondary gate and a second secondary gate.
Structural design and analysis of micromachined ring-type vibrating sensor of both yaw rate and linear acceleration
(2005-01-14)
Weng, JH
;
Chieng, WH
;
Lai, JM
;
機械工程學系
;
Department of Mechanical Engineering
This work presents the design and analysis of a micromachined ring-type motion sensor which can sense both the yaw rate and linear acceleration of a device in that it is installed. It integrates the functions of a gyroscope and an accelerometer. The design of the microstructure is based on the structure of a vibrating ring gyroscope. The analysis, considering the symmetry of the structure, implies that the rotational symmetry and mirror symmetry of the microstructure markedly affect the performance of the sensor. The modes of vibration determined using finite element analysis and the theoretical calculation of the resonant frequency of the structure are presented. The sensitivities of the characteristic of the sensor to the design specification, the fabrication errors and the theoretical errors are discussed. The structure is fabricated based on deep silicon etching and wafer bonding techniques. The process is developed for eliminating the aspect ratio dependent effect (ARDE) in dry etching process. (C) 2004 Elsevier B.V. All rights reserved.
Effect of surface stabilization of nanoparticles on luminescent characteristics in ZnO/poly(hydroxyethyl methacrylate) nanohybrid films
(2005-01-14)
Hung, CH
;
Whang, WT
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Highly transparent and stable luminescent ZnO/poly(hydroxyethyl methacrylate) nanocomposites have been synthesized via a nanoparticle surface modified method. 3-(Trimethoxysilyl)propyl methacrylate (TPM) was used as the stabilizing agent in a simple, mild sol-gel route to prepare TPM-modified ZnO nanoparticles. The existence of TPM on the nanoparticle surface effectively promotes the stability of colloidal ZnO nanoparticles and the compatibility between the inorganic nanoparticles and the organic matrix in the solid nanohybrid. The resulting ZnO/PHEMA nanocomposites with TPM-modified nanoparticles have better dispersibility and controllable luminescent properties. The characteristics of TPM-modified and unmodified ZnO nanoparticles have been studied by ultraviolet-visible (UV-vis) absorption spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and (1)H NMR spectroscopy.
Repacking on demand for speed-sensitive channel assignment
(2005-01-14)
Tsai, HM
;
Pang, AC
;
Lin, YC
;
Lin, YB
;
資訊工程學系
In mobile telecommunications networks, radio channels are limited resources that should be carefully allocated. To increase network capacity, channel assignment can be exercised in a hierarchical cellular network (HCN). By considering the speeds of MSs, we propose an HCN channel assignment approach called repacking on demand (RoD). A simulation model is developed to investigate the performance of RoD and some previously proposed approaches for HCN. Our study quantitatively shows that RoD significantly outperforms the previous proposed approaches. (C) 2004 Elsevier B.V. All rights reserved.
On power and sample size calculations for Wald tests in generalized linear models
(2005-01-15)
Shieh, G
;
管理科學系
;
Department of Management Science
A Wald test-based approach for power and sample size calculations has been presented recently for logistic and Poisson regression models using the asymptotic normal distribution of the maximum likelihood estimator, which is applicable to tests of a single parameter. Unlike the previous procedures involving the use of score and likelihood ratio statistics, there is no simple and direct extension of this approach for tests of more than a single parameter. In this article, we present a method for computing sample size and statistical power employing the discrepancy between the noncentral and central chi-square approximations to the distribution of the Wald statistic with unrestricted and restricted parameter estimates, respectively. The distinguishing features of the proposed approach are the accommodation of tests about multiple parameters, the flexibility of covariate configurations and the generality of overall response levels within the framework of generalized linear models. The general procedure is illustrated with some special situations that have motivated this research. Monte Carlo simulation studies are conducted to assess and compare its accuracy with existing approaches under several model specifications and covariate distributions. (C) 2003 Elsevier B.V. All rights reserved.
Delayed onset of return flow by substrate inclination in model horizontal longitudinal MOCVD processes
(2005-01-15)
Kuo, WS
;
Wang, CY
;
Tuh, JL
;
Lin, TF
;
機械工程學系
In this study an experimental flow visualization is carried out to investigate how the substrate inclination affects the buoyancy-induced return flow structure in mixed convection of gas in a horizontal rectangular duct. The return flow is driven by a heated circular disk embedded in the bottom plate of the duct. simulating that in a horizontal longitudinal MOCVD reactor. Specifically, the bottom plate of the duct is inclined so that the gas flow in the duct is accelerated, causing the buoyancy-to-inertia ratio to decrease in the main flow direction. In the experiment. the Reynolds and Rayleigh numbers of the flow at the duct inlet are respectively varied from 3.7 to 79.7 and from 90,40 to 24,000 for the inclined angle of the bottom plate fixed at 0degrees, 0.34degrees and 0.97degrees. Particular attention is paid to delineating the spatial changes of the return flow structure with the plate inclination angle and to how the bottom plate tilting possibly, suppresses and stabilizes the flow. The results show a substantial delay in the onset of the return flow and the effctive suppression of the buoyancy-driven unstable vortex flow by the bottom plate inclination. Besides, the bottom, plate inclination can effectively weaken the return flow at slightly higher Reynolds numbers. An empirical equation is provided to correlate the present data for the onset of the return flow in the duct with its bottom inclined at 0: and 0.97degrees. (C) 2004 Elsevier B.V. All rights reserved.
The optimal consecutive-k-out-of-n : G line for n <= 2k
(2005-01-15)
Jalali, A
;
Hawkes, AG
;
Cui, LR
;
Hwang, FK
;
應用數學系
Two proofs for the problem in the title have been published but both are incomplete. In this note we observe the subtle errors in these proofs and give a new proof by a different approach. (C) 2003 Elsevier B.V. All rights reserved.
砷化鎵元件背面銅金屬化之製作方法
(2005-01-16)
李承士
;
張翼
本發明砷化鎵元件背面銅金屬化之製作方法，係將砷化鎵元件背面金屬化金屬由金改為銅，由於銅的阻值較低，且散熱與機械強度亦較金優異。因此，以銅作為金屬化金屬之元件，可改善元件的散熱、機械強度、導電度，更可增進元件的特性及可靠度。並藉由鎢(W)、氮化鎢(WN)、氮化鈦鎢(TiWN)等薄膜作為擴散阻障層，有效阻擋銅易擴散入砷化鎵基材而改變元件特性之問題。
那羅文學屋蓋在尖石上
(2005-01-16)
陳希林
反馳式電流諧波校正之交流轉直流轉換器
(2005-01-16)
張隆國
;
劉興富
本發明係一種反馳式電流諧波校正之交流轉直流轉換器，其具備快速輸出負載調整率，在這轉換器中的變壓器具有三個繞組，而取代先前技術中的大電感，因此節省了將近一半的磁性材料，透過三個繞組圈數的調整可以使輸入電容耐壓低於450v／dc，即使輸入電壓90v／ac～265v／ac的範圍也可讓輸入電容耐壓低於450v／dc，這部分是非常重要的特色，同時這新型轉換器輸入電流符合IEC61000–3–2規範要求。
中央大學、陽明大學跨校創意學程
(國立陽明大學, 2005-01-17)
陽明電子報編輯小組
課程名稱：生物科技發展的啟示開課學期：九十三學年第二學期學分數：二學分授課教師：翟建富老師、郭文華老師等講座課程上課時間：週四15:30-17:20 上課地點：二教223教室
腦科學研究中心 Neural Club
(國立陽明大學, 2005-01-17)
陽明電子報編輯小組
時　間：1月18日(二)中午12:00 主講人：林蔚靖教授（陽明生藥所）講　題：Role of PICK1, a Protein Kinase Ca Anchoring Protein, in Etopside-induced Apoptosis 地　點：陽明大學護理館三樓301會議室
開開心心熱熱鬧鬧迎新春
(國立陽明大學, 2005-01-17)
陽明電子報編輯小組
不知不覺中，2005年悄然而至。開春以來，一連串的開工動土、公視拍攝、國際研討會以及羽球比賽，熱鬧登場，將校園景象喧擾得一片嘩然，連杜鵑花都紛紛綻放，透露出早春訊息。