Browsing by Issue Date, starting with "2005-12-12"

Now showing 1 - 20 of 65552

Miscibility, thermal characterization and crystallization of poly(L-lactide) and poly(tetramethylene adipate-co-terephthalate) blend membranes
(2005-12-12)
Liu, TY
;
Lin, WC
;
Yang, MC
;
Chen, SY
;
材料科學與工程學系
Binary blend membranes of biodegradable poly(L-lactide) (PLLA) with poly(tetramethylene adipate-co-terephthalate) (PTAT) copolymer were prepared by solution casting via air evaporation. The miscibility of PLLA/PTAT blends was studied by dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA) in a tensile mode. Differential scanning calorimetry (DSC) measurement was carried out. The surface microstructure and tensile properties of the blend membranes were examined using atomic force microscopy (AFM) and tensile tester. It was concluded that PLLA/PTAT blends should be partially miscible for all ranges of compositions. Higher roughness and porosity were observed for the blend containing 50% PTAT, suggesting more phase separation occurred. The DSC analysis showed that the fusion enthalpy and crystallinity (X-c) of the PLLA-rich phase decreased with increasing PTAT content. Solidification process strongly suggested that the crystallization rate was accelerated by blending with 25% PTAT content, which served as the nucleation agent. Furthermore, the crystallization rate coefficient (CRC) depended on the blending miscibility and cooling rate in the non-isothermal crystallization process. Besides, PTAT addition could be proved to enhance the thermal stability and elongation of resulting blend membranes, even superior to those properties of poly(lactic acid-co-glycolic acid) (PLGA). (c) 2005 Published by Elsevier Ltd.
Highly stable organic light-emitting devices with a uniformly mixed hole transport layer
(2005-12-12)
Tsai, CH
;
Liao, CH
;
Lee, MT
;
Chen, CH
;
應用化學系
Highly stable organic light-emitting devices were made by using a uniformly mixed hole transport layer (UM-HTL) composed of a mixture of 2-methyl-9,10-di(2-naphthyl)anthracene (MADN) and N,N-bis(1-naphthyl)-N,N-'-diphenyl,1,1(')-biphenyl-4,4(')-diamine (NPB) in a 3:7 (MADN:NPB) ratio. The lifetime of 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-benzo[l]-pyrano[6,7,8-ij]quinolizin-11-one doped green device with UM-HTL can be greatly improved to 2.7 times longer than that of the conventional device (NPB based HTL) without impacting on its driving voltage and emissive color significantly. This improvement in stability can be attributed to the fact that the unstable [Alq(3)(+)] species formed by electro-oxidation have been effectively suppressed.
High-extinction-ratio micro polarizing beam splitter for short wavelength optical storage applications
(2005-12-12)
Lee, CH
;
Chiu, Y
;
Shieh, HPD
;
電控工程研究所
;
光電工程學系
A surface-micromachined high-extinction-ratio polarizing beam splitter (PBS) using low absorptive silicon nitride layers for blue wavelength applications are demonstrated. The micro polarizing beam splitter consists of novel stack of two silicon nitride layers separated by an air gap. A PBS optimization model is established to achieve both high extinction-ratio and adequate process margin. The polarization extinction ratios of 25 dB for the reflected light and 15 dB for the transmitted light were experimentally achieved lambda=405 nm. The fabrication of the PBS is compatible with other micro diffractive elements to build a micro optical bench, thus, feasible for short wavelength optical storage applications. (c) 2005 Optical Society of America.
Synthesis and characterization of H-bonded side-chain and crosslinking LC polymers containing donor/acceptor homopolymers and copolymers
(2005-12-12)
Lin, HC
;
Hendrianto, J
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Side-chain copolymers consisting of proton acceptors (stilbazoles) and proton donors (benzoic acids) connected to polyacrylate backbones with different methylene spacer lengths are prepared by tuning their donor/acceptor molar ratios. The H-bonded copolymer networks are formed once they were synthesized, and showed more homogenous phase behavior than the physical blending supramolecular networks composed of donor and acceptor homopolymers. Analogous monomer-monomer and polymer-monomer (H-bonded side-chain polymer) complexes of similar structures are also investigated. According to DSC, POM, and XRD studies, it reveals that the copolymers with various spacer lengths and donor/acceptor molar ratios show the smectic A (S-A) phase. The d spacing values of XRD results suggest that the H-bonded copolymers may be constructed by either a monolayer or an interdigitated bilayer structure. Generally, the d spacing values of copolymers (in the SA phase) increase with higher H-bonded crosslinking density between benzoic acids and stilbazoles, i.e. decrease with higher molar ratios of benzoic acids, which may be owing to the formation of hydrogen bonds between benzoic acids from different backbones. The isotropization temperatures of the H-bonded blends and copolymers increase as the molar ratios of benzoic acids increase, while the higher H-bonded crosslinking density between benzoic acids and stilbazoles stabilizes the liquid crystalline phase. (c) 2005 Published by Elsevier Ltd.
Wireless audio and burst communication link with directly modulated THz photoconductive antenna
(2005-12-12)
Liu, TA
;
Lin, GR
;
Chang, YC
;
Pan, CL
;
光電工程學系
We demonstrate transmission of audio and burst signals through a prototype THz analog communication link employing laser-gated low-temperature-grown GaAs dipole antenna as THz emitter and receiver. The transmission distance is about 100 cm. By using a direct voltage modulation format, we successfully demodulated a burst signal with a rising time of 41 mu s. The corresponding modulating bandwidth achieved was 23 kHz in this first experiment. Noise analysis reveals a 10% power fluctuation in the received signal with on-off extinction ratio of greater than 1000. The transmission of a six-channel analog and burst audio signal with least distortion is also demonstrated. We further demonstrate the fidelity of the transmission of a melody through the THz link with and without any amplification.
Vanadium-doped indium tin oxide as hole-injection layer in organic light-emitting devices
(2005-12-12)
Chen, TH
;
Liou, Y
;
Wu, TJ
;
Chen, JY
;
顯示科技研究所
Organic light-emitting devices were fabricated by using vanadium-doped indium tin oxide (ITO) as the hole-injection layers between the hole transport layer, N,N-'-dia(1-napthl)-N,N-'-diphenyl benzidine and the ITO anode. The vanadium-doped ITO layer was 15-nm thick with three different vanadium concentrations (6, 10.5, and 12.5 mol %). Three different resistivities (10, 500, and 10 000 Omega cm) and work functions (5, 5.2, and 5.4 eV) were obtained. The device with 6 mol % V-doped ITO layer possessing the least resistivity (10 Omega cm) and work function (5 eV) has the lowest turn-on voltage (below 3 V), the lowest operating voltage (below 7 V), the highest luminance (1000 cd/m(2) below 7 V), and the highest power efficiency (>5 1m/W at 10 mA/cm(2)) among all. Such performance was attributed to the balance between the carrier concentration and the energy barrier for the hole injection.
Synthesis and characterization of an efficiently fluorescent poly(phenylenevinylene) possessing pendant dendritic phenyl groups
(2005-12-13)
Dinakaran, K
;
Hsiao, SM
;
Chou, CH
;
Shu, SL
;
Wei, KH
We have synthesized a thermally stable and high molecular weight fluorescent poly(phenylenevinylene) (PPV) incorporating side-chain-tethered dendritic phenyl groups (DENPPV) through Gilch route; this DENPPV has a low abundance of tolane-bisbenzyl defects. Intramolecular energy transfer from the dendritic phenyl side group to the PPV backbone was evidenced from UV-vis and photoluminescence spectra of the DENPPV polymer and its model compound. Copolymers of DENPPV with 2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene (MEHPPV) display excellent photoluminescence both in solution and in the solid state; the highest quantum yield we observed was 82%. The electroluminescence of the copolymer MEHPPV/DENPPV (molar ratio: 25/75) was 70% higher than that of MEHPPV (0.12 lm/W vs 0.07).
Efficient diode-pumped actively Q-switched Nd : YAG/BaWO4 intracavity Raman laser
(2005-12-15)
Chen, YF
;
Su, KW
;
Zhang, HJ
;
Wang, JY
;
Jiang, MH
Barium tungstate (BaWO4) is employed to achieve efficient stimulated Raman scattering conversion in a compact diode-pumped actively Q-switched Nd:YAG laser. With an incident pump power of 9.2 W, 1.56 W of 1181 nm first-Stokes average output power was generated at a pulse repetition rate of 20 kHz, corresponding to an optical-to-optical conversion efficiency of 16.9%. (c) 2005 Optical Society of America
Improved common-path optical heterodyne interferometer for measuring small optical rotation angle of chiral medium
(2005-12-15)
Lee, JY
;
Su, DC
;
光電工程學系
;
Department of Photonics
An improved common-path optical heterodyne interferometry for measuring small optical rotation angle of chiral liquid is presented. The optical rotation angle can be determined by the phase difference between the test and reference signals. By means of inserting, a phase retarder behind the test sample, the measuring resolution of optical rotation angle is greatly enhanced. The theoretical prediction indicates the resolution is better than 3.5 x 10(-5) degree. (c) 2005 Elsevier B.V. All rights reserved.
Cryptanalysis of the improved authenticated key agreement protocol
(2005-12-15)
Chang, TY
;
Yang, CC
;
Yang, YW
;
資訊工程學系
;
Department of Computer Science
Hsu et al. recently pointed out that the Ku-Wang scheme is vulnerable to modification attack and further proposed an improvement on their scheme. However, this article will show the improvement which they claim is still vulnerable by off-line password guessing attack. (c) 2005 Published by Elsevier Inc.
低溫多晶矽薄膜電晶體主動層之雷射再結晶方法
(2005-12-16)
葉清發
;
陳添富
;
羅正忠
本發明係一種低溫多晶矽薄膜電晶體主動層之雷射再結晶方法，其係利用具單一方向性之非等向性電漿蝕刻(Anisotropic Plasma Etching)在薄膜電晶體主動層側壁形成一間距矽(silicon–spacer)，該間距矽提供了一雷射側向再結晶機制與可防止雷射再結晶後主動層微縮或剝落變形等現象，此發明技術可使通道內之矽晶粒變大但在製程上不需額外光罩，如此同時提升元件特性、提高元件均勻度與節省製程成本，此技術在現今低溫多晶矽薄膜電晶體(LTPS–TFT)領域中將會是一項關鍵技術。
薄膜式電磁線圈之製作方法
(2005-12-16)
呂宗熙
;
蘇侯舉
本發明係提供一種薄膜式電磁線圈之製作方法，係利用原子力顯微鏡進行微影(Force Lithography)加工，製造具有奈米等級的電磁線圈，進而提高其磁場強度；其係利用原子力微影顯微技術於一薄膜基材上進行加工，使其呈現凹陷結構，再經由一微機電製程，形成一具有奈米等級、高磁場強度的薄膜式電磁線圈，以達到降低成本、提升電磁線圈效率之功能。
Equilibrium first-order melting and second-order glass transitions of the vortex matter in Bi2Sr2CaCu2O8
(2005-12-16)
Beidenkopf, H
;
Avraham, N
;
Myasoedov, Y
;
Shtrikman, H
;
Zeldov, E
The thermodynamic H-T phase diagram of Bi2Sr2CaCu2O8 was mapped by measuring local equilibrium magnetization M(H,T) in the presence of vortex shaking. Two equally sharp first-order magnetization steps are revealed in a single temperature sweep, manifesting a liquid-solid-liquid sequence. In addition, a second-order glass transition line is revealed by a sharp break in the equilibrium M(T) slope. The first- and second-order lines intersect at intermediate temperatures, suggesting the existence of four phases: Bragg glass and vortex crystal at low fields, glass and liquid at higher fields.
用以靜電放電防護之矽控整流器
(2005-12-16)
柯明道
;
林昆賢
本發明係提供一種用以靜電放電防護之矽控整流器，其包含：一第一電極和一第二電極做為兩極、一P型電晶體(PMOS)、一N型電晶體(NMOS)以及一矽控整流器(Silicon Controlled Rectifier,SCR)結構；係藉由利用電源間的寄生矽控整流器(SCR)以達到全晶片靜電放電防護電路設計(Whole–chip ESD protection design)；其係適用於積體電路產品、IC設計產業以及晶圓代工產業。
Suppliers capability and price analysis chart
(2005-12-18)
Chen, KL
;
Chen, KS
;
Li, RK
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
To remain competitive in customer-oriented economics, the major parties in the supply chain should be integrated and managed effectively to respond to customer needs. Thus, the efficiency of the entire supply chain is a main concern, and is determined by the members of that supply chain. Partner selection thus becomes one of the key steps in supply chain construction. Given buyer-supplier information asymmetry, obtaining complete information from suppliers is difficult, since some supplier attributes cannot be definitely and quantitatively measured. This study establishes a suppliers capability and price analysis chart (SCPAC) focused on the case where the specification limits are symmetric about the target for evaluating supplier performance which applies the process incapability index C-pp introduced by Greenwich and Jahr-Schaffrath (International Journal of Quality & Reliability Management 12 (1995) 58) to measure supplier quality performance and the price index I-p is proposed here to display the difference between budget and component price. Practitioners can instantly and visually obtain information based on the locations of suppliers and price indices on SCPAC. SCPAC also provides clear directions for quality improvement, such as process accuracy and precision. SCPAC thus is an effective and efficient method for evaluating suppliers, which can simplify supplier evaluation, facilitate their effective visual selection, and provide insights into the process situation of suppliers who can become technological innovation partners. (c) 2004 Published by Elsevier B.V.
Polymer hot-carrier transistor
(2005-12-19)
Chao, YC
;
Yang, SL
;
Meng, HF
;
Horng, SF
;
物理研究所
Metal-base hot-carrier transistor with conjugated polymer emitter and collector is demonstrated. The device is fabricated by multiple spin coating with the metal base sandwiched between two polymers. A thin insulating layer of LiF is inserted between the emitter and base to enhance the hot carrier kinetic energy and reduce mutual dissolution. Using poly(9-vinylcarbazole) as the emitter, Al as the base, and poly(3-hexylthiophene) as the collector, common-emitter current gain of 25 is obtained with operation voltage as low as 5 V.
Highly efficient white organic electroluminescent devices based on tandem architecture
(2005-12-19)
Chang, CC
;
Chen, JF
;
Hwang, SW
;
Chen, CH
;
電子物理學系
Two types of tandem organic light-emitting diodes (OLEDs) with white-light emission have been developed by using Mg:Alq(3)/WO3 as the interconnecting layer. While the Commission Internationale d'Eclairage (CIE) coordinates of the tandem device with individual blue- and yellow-emitting OLEDs was sensitive to the viewing angle and the operating time, the tandem device connecting two white-emitting OLEDs was considerably less. At an optimal WO3 thickness of 5 nm, the tandem two-unit device produced three higher luminance efficiency than that expected of a single-unit device. A maximum efficiency of 22 cd/A was achieved by the tandem device comprised of two white-fluorescent OLEDs, and the projected half-life under the initial luminance of 100 cd/m(2) was over 80 000 h.
用於金屬編碼唯讀記憶體中消除耦合雜訊干擾之方法
(2005-12-21)
張孟凡
;
溫岸
本發明提出一種用於金屬編碼唯讀記憶體中消除耦合雜訊干擾之方法，此金屬編碼唯讀記憶體包括複數條字元線、複數條位元線、複數個預充電電晶體以及複數個緊固電晶體。當這些位元線其中之一被選取時，相鄰兩側之位元線藉由緊固電晶體而被緊固(clamping)至一固定之電壓值(VDD或是GND或是其他電壓)，這種緊固方法於這些鄰近位元線上不會產生壓降以及能同時於所選擇之位元線上除去耦合雜訊，進而除去高速金屬編碼唯讀記憶體中耦合雜訊所引起之讀碼失敗以及達到較高的速度。
The electrochemical polishing behavior of porous austenitic stainless steel (AISI 316L) in phosphoric-sulfuric mixed acids
(2005-12-21)
Chen, SC
;
Tu, GC
;
Huang, CA
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The electrochemical polishing of porous austenitic stainless steel (PASS), AISI 316L, in the phosphoric-sulfuric mixed acid with volume-ratio of 1: 1, 2: 1 and 3: 1 at temperature ranging from 60 to 80 degrees C was studied. Electrochemical polishing of PASS was performed in the potential located in the limiting-current plateau of its anodic polarization curve using a rotating cylinder electrode (RCE). The results show that the electrochemical polishing of PASS is strongly affected by the volume ratio of the mixed acid and the polishing temperature, yet very little by the potentiostatic polishing charge. An optimal brightening and leveling surface of PASS could be achieved by polishing in 2: 1 v/v mixed acid at 70 degrees C. Whereas, polishing in 1 : 1 and 2: 1 v/v ratios at and above 75 degrees C would result in formation of enlarged pores on the PASS surface due to high dissolution rate within the pores. Pores with rounded edges in the surface morphology of PASS was shown when polishing in 3: 1 v/v mixed acid at temperature ranging from 60 to 80 degrees C. The effects of temperature, acid volume-ratio as well as potentiostatic polishing charge on polishing behavior were discussed based on the results of electrochemical test and the polished surface morphology using scanning electron microscope (SEM). (c) 2005 Elsevier B.V. All rights reserved.
動態影像估測之裝置及方法
(2005-12-21)
吳炳飛
;
瞿忠正
;
陳昭榮
;
彭信元
;
游東龍
本發明係有關於一種動態影像估測之裝置及方法，此裝置具有複數個二維差值累積器、複數個位移暫存器、比較器、及加法器，二維差值累積器係用以執行變動影像及先前影像之比較，並輸出複數個對應之絕對差總和，再由比較器對此些絕對差總和進行比較，以取得一個最小之絕對差總和，因而得知變動影像與先前影像之運動向量，並記錄之。如此一來，影像資料僅需儲存變動影像及其運動向量，而非整幅之目前影像，故能減少影像資料之資料量。