Browsing by Issue Date, starting with "2007-04-18"

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夜這個黑道
(2007-04-18)
管管
Low-density high-toughness alloy and the fabrication method thereof
(2007-04-19)
Liu, Tzeng-Feng
;
Lee, Jian-Wei
The present invention discloses a low-density high-toughness alloy and the fabrication method thereof. The alloy of the present invention consists essentially of: by weight percent, equal to or greater than 23% but lower than or equal to 33% manganese, equal to or greater than 8.1% but lower than or equal to 9.8% aluminum, equal to or greater than 3% but lower than or equal to 7.8% chromium, equal to or greater than 0.6% but lower than or equal to 1.2% carbon, equal to or greater than 0.1% but lower than or equal to 0.24% silicon and the balance of iron. The golf-club head made from the abovementioned alloy can obtain superior elongation, strength, damping capacity, and corrosion resistance even without any heat treatment, or any hot/cold working, such as forging and rolling; therefore, the fabrication cost thereof can be obviously reduced.
Passively Q-switched Yb3+: YCa4O(BO3)(3) laser with InGaAs quantum wells as saturable absorbers
(2007-04-20)
Liang, H. C.
;
Huang, J. Y.
;
Su, K. W.
;
Lai, H. C.
;
Chen, Y. F.
A diode-pumped Yb:YCOB laser at 1086 nm is passively Q switched by using InGaAs quantum wells as saturable absorbers and utilizing the Bragg mirror structure as an output coupler. With an absorbed pump power of 9.2 W the laser produces pulses of 100 ms duration with average pulse energy of as much as 165 mu J at a pulse repetition rate of 7 kHz. (c) 2007 Optical Society of America.
Interplay of anisotropy and disorder in the doping-dependent melting and glass transitions of vortices in Bi2Sr2CaCu2O8+delta
(2007-04-20)
Beidenkopf, H.
;
Verdene, T.
;
Myasoedov, Y.
;
Shtrikman, H.
;
Zeldov, E.
We study the oxygen doping dependence of the equilibrium first-order melting and second-order glass transitions of vortices in Bi2Sr2CaCu2O8+delta. Doping affects both anisotropy and disorder. Anisotropy scaling is shown to collapse the melting lines only where thermal fluctuations are dominant. Yet, in the region where disorder breaks that scaling, the glass lines are still collapsed. A quantitative fit to melting and replica symmetry-breaking lines of a 2D Ginzburg-Landau model further reveals that disorder amplitude weakens with doping, but to a lesser degree than thermal fluctuations, enhancing the relative role of disorder.
Crystal structure of Helicobacter pylori formamidase AmiF reveals a cysteine-glutamate-lysine catalytic triad
(2007-04-20)
Hung, Chiu-Lien
;
Liu, Jia-Hsin
;
Chiu, Wei-Chun
;
Huang, Shao-Wei
;
Hwang, Jenn-Kang
Helicobacter pylori AmiF formamidase that hydrolyzes formamide to produce formic acid and ammonia belongs to a member of the nitrilase superfamily. The crystal structure of AmiF was solved to 1.75 angstrom resolution using single-wavelength anomalous dispersion methods. The structure consists of a homohexamer related by 3-fold symmetry in which each subunit has an alpha-beta-beta-alpha four-layer architecture characteristic of the nitrilase superfamily. One exterior alpha layer faces the solvent, whereas the other one associates with that of the neighbor subunit, forming a tight alpha-beta-beta-alpha-alpha-beta-beta-alpha dimer. The apo and liganded crystal structures of an inactive mutant C166S were also determined to 2.50 and 2.30 angstrom, respectively. These structures reveal a small formamide-binding pocket that includes Cys(166), Glu(60), and Lys(133) catalytic residues, in which Cys166 acts as a nucleophile. Analysis of the liganded AmiF and N-carbamoyl D-amino acid amidohydrolase binding pockets reveals a common Cys-Glu-Lys triad, another conserved glutamate, and different subsets of ligand-binding residues. Molecular dynamic simulations show that the conserved triad has minimal fluctuations, catalyzing the hydrolysis of a specific nitrile or amide in the nitrilase superfamily efficiently.
攝影機參數校正方法
(2007-04-21)
陳冠文
;
洪一平
本發明為一種攝影機參數校正方法，主要是基於受到地心引力影響的運動物體對攝影機或相機進行校正。此方法首先使運動物體由於受到的地心引力影響而構成拋物線之運動軌跡、使攝影機以特定的快門速度，對在運動路徑中運動的運動物體連續拍攝，而獲得複數個特定拍攝時間和在影像座標上的特定xy位置的校正影像、以及依據透視投影幾何方程式，而基於影像座標的位置和拍攝時間獲得用來求出攝影機的內部參數和外部參數之平面投影轉換矩陣。
低密度高韌性合金材料及其製法
(2007-04-21)
劉增豐
;
李堅瑋
一種低密度高韌性合金材料及其製法，其主要組成為以重量百分比計，大於等於23小於等於33的錳，大於等於8.1小於等於9.8的鋁，大於等於3小於等於7.8的鉻，大於等於0.6小於等於1.2的碳，大於等於0.1小於等於0.24的矽及其餘比例為鐵之合金材料。上所揭示之合金成份之合金材料製作高爾夫球頭時，不須任何熱處理及鍛造、軋延等熱作和冷作塑性加工，即可使高爾夫球頭具有極佳的延伸性、強度、吸震性及抗蝕性等特性，大幅降低目前的生產成本。
雷射微加工處理全光纖型元件之製作方法
(2007-04-21)
祁甡
;
陳南光
本案係指一種雷射微加工處理全光纖型元件之製作方法，係直接對光纖之部分光殼施以雷射切削去除，使得光纖內的消逝場(evanescent field)能夠裸露出來，切削的深度可藉由量測雷射光干涉條紋間距的方法得知；雷射切削形成的消逝場之作用長度則可透過改變光纖曲率半徑控制。將側削後之光纖彼此靠合，使其光消逝場能夠發生耦合後予以加熱熔合或施以熔燒拉錐(fuse-tapering)，即可用來製作光纖耦合器、光塞取多工器(add/drop multiplexer)、光纖窄波道多工/解多工器及光纖光柵等光纖元件。
Self-organized tantalum oxide nanopyramidal arrays for antireflective structure
(2007-04-23)
Wu, Chia-Tien
;
Ko, Fu-Hsiang
;
Lin, Chun-Hung
;
材料科學與工程學系
;
材料科學與工程學系奈米科技碩博班
A self-organized tantalum oxide nanopyramidal structure without tedious semiconductor processing is proposed in this letter. Construction of pyramid arrays with a close-packed periodicity of 200 nm and a height of 200 nm was achieved by the anodic alumina template method directly on the substrate. The tantalum oxide nanopyramidal structure was formed as the underlying tantalum film oxidized and localized precisely by the pore of alumina. The reflectance from the spectroscopic measurement suggests that the nanopyramidal array structures have more broadband antireflection (< 2%) than the nanodot arrays and thin film structures. (c) 2007 American Institute of Physics.
Ce3+/Eu2+ codoped Ba2ZnS3: A blue radiation-converting phosphor for white light-emitting diodes
(2007-04-23)
Yang, Woan-Jen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
The Ce3+/Eu2+ codoped Ba2ZnS3 phosphor shows intense blue absorption and tunable green-to-red emission. The energy transfer from Ce3+ to Eu2+ in this phosphor has been demonstrated to be a resonant type via an electric dipole-dipole mechanism. The Ba2ZnS3:Ce3+,Eu2+ phosphor would be the great potential application as a blue radiation-converting phosphor for white light-emitting diodes. (c) 2007 American Institute of Physics.
A theoretical study of surface reduction mechanisms of CeO2 (111) and (110) by H-2
(2007-04-23)
Chen, Hsin-Tsung
;
Choi, Yong Man
;
Liu, Meilin
;
Lin, M. C.
;
應用化學系分子科學碩博班
Reaction mechanisms for the interactions between CeO2(111) and (110) surfaces are investigated using periodic density functional theory (DFT) calculations. Both standard DFT and DFT+U calculations to examine the effect of the localization of Ce4f states on the redox chemistry of H-2-CeO2 interactions are described. For mechanistic studies, molecular and dissociative local minima are initially located by placing an H-2 molecule at various active sites of the CeO2 surfaces. The binding energies of physisorbed species optimized using the DFT and DFT+U methods are very weak. The dissociative adsorption reactions producing hydroxylated surfaces are all exothermic; exothermicities at the DFT level range from 4.1 kcalmol(-1) for the (111) to 26.5 kcalmol(-1) for the (110) surface, while those at the DFT+U level are between 65.0 kcalmol(-1) for the (111) and 81.8kcalmol(-1) for the (110) surface. Predicted vibrational frequencies of adsorbed OH and H2O species on the surfaces are in line with available experimental and theoretical results. Potential energy profiles are constructed by connecting molecularly adsorbed and dissociatively adsorbed intermediates on each CeO2 surface with tight transition states using the nudged elastic band (NEB) method. It is found that the U correction method plays a significant role in energetics, especially for the intermediates of the exit channels and products that are partially reduced. The surface reduction reaction on CeO2(110) is energetically much more favorable. Accordingly, oxygen vacancies are more easily formed on the (110) surface than on the (111) surface.
Effect of lath microstructure on the mechanical properties of flow-formed C-250 maraging steels
(2007-04-25)
Lee, Yen-Jung
;
Kung, Ming-Chueh
;
Lee, I-Kang
;
Chou, Chang-Pin
;
機械工程學系
A solution treated C-250 maraging steel tubing pre-form was cold forward flow-formed into a seamless tube to attain a 79% wall thickness reduction. Various heat treatments were then conducted on the tube to strengthen the material. This study found that although direct aging treatment could generate the tensile strength exceeded the specification's requirement in all the heat treatment attempts, the C-250 steel suffered loss of ductility in percentage elongation. Through "solution + aging" treatment, the steel's ductility was much improved and tensile properties can still meet the specification. The pre-treatment of high homogenization temperature could produce coarse lath martensitic microstructure and result in a decrease of the tensile strength of the C-250 steel. Furthermore, the C-250 steel also showed the presence of seemingly globular precipitates within the lath structure. Detailed discussion of mechanical properties obtained for each of the heat-treated steels in terms of microstructures and metallographic works was presented. (c) 2006 Elsevier B.V. All rights reserved.
Context-aware frame memory scheme for motion compensation in video decoding
(2007-04-26)
Chang, Nelson Yen-Chung
;
Chang, Tian-Sheuan
The present invention provides a context-aware frame memory scheme for motion compensation in video decoding, which utilizes a motion compensator to receive a data block from input video decoding, follow by processing both inputted context characteristic of residual block and motion vector respectively. The conception of technology is first based on the context characteristic of input video data decoding block, if there is no residual value and motion vector, it will be defined as “perfect match block”; otherwise, “non-perfect match block” instead. Then, the circuit architecture for memory accessing in video decoding provided by present invention will perform different memory access steps for the above mentioned two types of block. If one determines that a block is “non-perfect match block”, selectively choose the reference frame as a back-up data; On contrary, if a block is “perfect match block”, it represents there is no difference between both reference frame and reconstructive frame, hence no access is required to the main frame memory, which means that the access frequency can be minimized; therefore, it can minimize the consumption of the memory capacity as well.
Novel vertical handover control algorithm for WLAN and UMTS
(2007-04-26)
Huang, Ching Yao
;
Chou, Chie Ming
In this invention, a novel vertical handover control algorithm, consisting of a throughput-based mapping function, QoS-based dynamic handover thresholds, and performance-based trigger timers, are proposed to resolve uncommon pilot problem, QoS requirements, and ping-pong effects, respectively. An analytic model based on a finite state machine is developed to evaluate the proposed algorithm in terms of the handover frequency and achievable throughput. A numerical analysis is also provided to further quantify the performance impacts.
Computer executable graphic method of generating animation elements
(2007-04-26)
Chen, Ming-Jang
A computer executable graphic method of generating animation elements realized with computer software is provided, which is capable of being plugged in a computer graphics application, recorded in a recording and storage medium, or executed on a computer executable platform. Through an operating mode of a graphic user interface provided by a graphics system, various objects can be established to form various animation elements, and the animation elements can be activated with a trigger event executed by an input device to generate various interactive animation effects. According to the present method, a user can operate in a graphic mode to establish and generate an interactive animation visually, simply, and rapidly.
Low refractive index Si nanopillars on Si substrate
(2007-04-30)
Lin, Gong-Ru
;
Chang, Ya-Chung
;
Liu, En-Shao
;
Kuo, Hao-Chung
;
Lin, Huang-Shen
Low refractive index of a stalagmitelike high-aspect-ratio Si nanopillar array on Si dry etched using a self-aggregated Ni nanodot mask is demonstrated, which exhibits two minimum reflectances of 1.23 and 1.4 with corresponding refractive indices of 1.25 and 1.48 at 400 and 1200 nm, respectively. Angular dependency of the transverse electrical mode reflectance at 632.8 nm of the surface roughened Si nanopillar array is released, and the Brewster angle of 63 degrees with equivalent refractive index of 1.5 is determined. (C) 2007 American Institute of Physics.
Nonvolatile low-temperature polycrystalline silicon thin-film-transistor memory devices with oxide-nitride-oxide stacks
(2007-04-30)
Liu, Po-Tsun
;
Huang, C. S.
;
Chen, C. W.
;
光電工程學系
;
顯示科技研究所
Nonvolatile memory devices with oxide-nitride-oxide stack structures were fabricated on glass substrates using low-temperature polycrystalline silicon technology. The Fowler-Nordheim tunneling scheme is more suitable than channel hot carrier injection for the programming of the polycrystalline silicon nonvolatile memory device. A memory window of 1.5 V can be obtained at a programming voltage of 20 V. After 10(4) programming/erasing cycles, a threshold voltage shift of 1.5 V is maintained. Furthermore, the proposed memory device exhibits good retention for 50 h at 60 degrees C without a significant decline in the memory window. (C) 2007 American Institute of Physics.
Effects of strained InGaN interlayer on contact resistance between p-GaN and indium tin oxide
(2007-04-30)
Lee, Chi-Ling
;
Lee, Wei-I
;
電子物理學系
;
Department of Electrophysics
Indium tin oxide (ITO), with its transparency and strong adhesion to GaN, has been used as a replacement for Ni/Au as a contact on p-GaN. However, ITO suffers from high contact resistance on p-GaN. In this work, low contact resistance between ITO and the p-GaN layer was consistently achieved using various strained InGaN layers as the interface layers between ITO and p-GaN layer. The doping of InGaN, whether n type or p type, has a relatively weak effect on the contact resistance as long as the thickness of the InGaN layer is adequately controlled. The secondary-ion-mass spectroscopy depth profile reveals that the n-type InGaN strained contact layer was also heavily doped with Mg. Results of this study demonstrate that the piezoelectric field between InGaN and p-GaN is important in reducing the barrier height of Ohmic contact. (c) 2007 American Institute of Physics.
Quantitative phase retrieval in transmission hard x-ray microscope
(2007-04-30)
Yin, Gung-Chian
;
Chen, Fu-Rong
;
Hwu, Yeukuang
;
Shieh, Han-Ping D.
;
Liang, Keng S.
Quantitative phase retrieval with a sub-100-nm resolution is achieved from micrographs of a zone plate based transmission x-ray microscope. A plastic zone plate containing objects of sizes from micrometers down to tens of nanometers is used as a test sample to quantify the retrieved phase. Utilizing the focal serial images in the image plane, the phase information is retrieved quantitatively across the entire range of sizes by combining the transport intensity equation and self-consistent wave propagation methods in this partial coherence system. The study demonstrates a solution to overcome the deficiency encountered in the two phase retrieval approaches. (c) 2007 American Institute of Physics.
Optical characteristics of a-plane InGaN/GaN multiple quantum wells with different well widths
(2007-04-30)
Ko, T. S.
;
Lu, T. C.
;
Wang, T. C.
;
Lo, M. H.
;
Chen, J. R.
a-plane InGaN/GaN multiple quantum wells of different widths ranging from 3 to 12 nm were grown on r-plane sapphire by metal organic chemical vapor deposition for investigation. The peak emission intensity of the photoluminescence (PL) reveals a decreasing trend as the well width increases from 3 to 12 nm. Low temperature (9 K) time-resolved PL study shows that the sample with 3-nm-thick wells has a better optical property with a fast exciton decay time of 0.57 ns. The results of cathodoluminescence and micro-PL scanning images for samples of different well widths further verify the more uniform and stronger luminescence intensity distribution observed for the samples of thinner quantum wells, indicating that the important growth parameters for a-plane InGaN/GaN multiple quantum wells could be dominated by the In fluctuation and crystal quality during the epitaxial growth. (c) 2007 American Institute of Physics.