Browsing by Issue Date, starting with "2007-11-26"

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Formation and nonvolatile memory effect of nickel-oxygen-silicon nanoparticles
(2007-11-26)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Yeh, Jui-Lung
;
Sze, Simon M.
;
Chang, Chun-Yen
This study reveals the formation of nickel-oxygen-silicon nanoparticles with nonvolatile memory effect by sputtering a commixed target in argon and oxygen ambiance. A transmission electron microscope clearly shows the embedded nanoparticles in the silicon oxide and the constituent was examined by x-ray photoelectron spectroscopy. The capacitor structure with embedded nickel-oxygen-silicon nanoparticles was also studied and it exhibited hysteresis characteristics after electrical operation. The memory window and retention of nickel-oxygen-silicon nanoparticles were enough to apply on nonvolatile memory. In addition, a physical mechanism was deduced to expound the role of oxygen in the formation of nickel-oxygen-silicon nanoparticles. (C) 2007 American Institute of Physics.
Microwave-assisted traceless synthesis of hydantion-fused beta-carboline scaffold
(2007-11-26)
Yeh, Wen-Pin
;
Chang, Wong-Jin
;
Sun, Mei-Lian
;
Sun, Chung-Ming
;
應用化學系
Multistep microwave-assisted reactions toward the synthesis of hydantoin-fused tricyclic tetrahydro-beta-carbolines on the soluble polymer support have been developed. Polymer-bound tryptophan with various aldehydes has been subjected to Pictet-Spengler reaction to obtain tricyclic beta-carboline conjugates. The terminal hydantoinyl moiety is constructed across polymer-bound beta-carbolines by the reaction with various isocyanates under microwave irradiation to form urea intermediate. Simultaneous intramolecular cyclization of urea followed by cleavage of the polymer support leads to a traceless synthesis of tetracyclic scaffolds in high yield and high purity. (c) 2007 Elsevier Ltd. All rights reserved.
Strategic design and synthesis of osmium(II) complexes bearing a single pyridyl azolate pi-chromophore: Achieving high-efficiency blue phosphorescence by localized excitation
(2007-11-26)
Cheng, Yi-Ming
;
Li, Elise Y.
;
Lee, Gene-Hsiang
;
Chou, Pi-Tai
;
應用化學系
We present the strategic design and synthesis of Os(II) complexes bearing a single pyridyl azolate T-chromophore with an aim to attain high efficiency blue phosphorescence by way of localized transition. It turns out that our proposal of localized excitation seems to work well upon anchoring a single)T-chromophore on the Os(II) complexes such that the control of MLCT versus pi pi* (or even LLCT) transitions is more straightforward. Among the titled complexes, [OS(CO)(3)(tfa)(fppz)] (1) and [Os(CO)(3)(tfa)(fbtz)] (5) (tfa = trifluoroacetate, (fppz)H = 3-(trifluoromethyl)5-(2-pyridyl)pyrazole, and (fbtz)H = 3-(trifluoromethyl)-5-(4-tert-butyl-2-pyridyl)-1,2,4-triazole) give the anticipated blue phosphorescence with efficiencies of 0.26 (lambda(max) = 460 nm) and 0.27 (lambda(max) = 450 nm), respectively. For their halide analogues [Os(CO)(3)(X)(fppz)] (2, X = Cl; 3, X Br; 4, X = 1) and phosphine-substituted isomeric derivatives [Os(tfa)(fppz)(PPh(2)Me)(2)(CO)] (6-8), the localization of the excitation energy seems to populate at certain vibrational modes with weak bonding strength and hence an associated shallow potential energy surface to induce a facile radiationless transition. Furthermore, their ancillary ligands play an important role in fine-tuning not only the energy gap but also the emission intensity, i.e., in manifesting the radiationless transition pathways. Our results clearly show that there is always a tradeoff upon varying the parameters in an aim to optimize the hue and efficiency of phosphorescence toward blue.
Growth of GaN film on 150 mm Si (111) using multilayer AlN/AlGaN buffer by metal-organic vapor phase epitaxy method
(2007-11-26)
Lin, Kung-Liang
;
Chang, Edward-Yi
;
Hsiao, Yu-Lin
;
Huang, Wei-Ching
;
Li, Tingkai
High quality GaN film was successfully grown on 150 mm Si (111) substrate by metal-organic vapor phase epitaxy method using AlN multilayer combined with graded AlGaN layer as buffer. The buffer layer structure, film quality, and film thickness are critical for the growth of the crack-free GaN film on Si (111) substrate. Using multilayer AlN films grown at different temperatures combined with graded Al(1-x)Ga(x)N film as the buffer, the tensile stress on the buffer layer was reduced and the compressive stress on the GaN film was increased. As a result, high quality 0.5 mu m crack-free GaN epitaxial layer was successfully grown on 6 in. Si substrate. (C) 2007 American Institute of Physics.
Infrared properties of CsGe(BrxCI1-x)3, nonlinear optical rhombohedral semiconductor
(2007-11-28)
Lin, Zhi-Guang
;
Tang, Li-Chuan
;
Chou, Chang-Pin
;
機械工程學系
;
Department of Mechanical Engineering
Innovative infrared nonlinear optical crystals CsGe( BrxCl1-x)(3) were synthesized. From their powder x-ray diffraction patterns, these crystals were characterized as rhombohedral structure with ( R3m, No 160) space group symmetry. The energy gap decreased from about 3.43 to 2.38 eV as the substitutional ratio, x, changed from zero to unity. Moreover, the powder second-harmonic generation ( PSHG) measurement of CsGeBr3 showed that its nonlinear optical efficiency is 9.64 times larger than that of rhombohedral CsGeCl3 and 28.29 times larger than that of KH2PO4 (KDP), and most important of all, that CsGe( BrxCl1-x)(3) is phase matchable. So the optical nonlinearity is approximately inversely proportional to the cube of the energy gap. The infrared transparent spectrum of rhombohedral CsGe( BrxCl1-x)(3) was extended to more than 30 mu m, which shows the potential in the realm of nonlinear optics and can be applied to the infrared region.
Size-dependent lattice dynamics of barium titanate nanoparticles
(2007-11-28)
Huang, Tung-Ching
;
Wang, Mei-Tan
;
Sheu, Hwo-Shuenn
;
Hsieh, Wen-Feng
;
光電工程學系
By applying a single-tetragonal-phase model to refine the crystal structure and the coupled-phonon model to analyze transverse optical ( TO) modes of BaTiO3 nanocrystals, we found, upon decreasing the particle size from 140 to 30 nm, that the tetragonality of BaTiO3 nanocrystallites is reduced accompanied by expanding unit-cell volume, which is the dominant mechanism for reducing giant LO-TO splitting in the BaTiO3 system. The weakening coupling of two low-frequency modes among three A(1) ( TO) phonons leads to changing the lowest one from a spectral dip to a peak, whereas the increasing coupling strength between two high-frequency modes repels them farther so that there is less reduction in spectral separation.
Field-emission properties of novel palladium nanogaps for surface conduction electron-emitters
(2007-11-28)
Lo, Hsiang-Yu
;
Li, Yiming
;
Chao, Hsueh-Yung
;
Tsai, Chih-Hao
;
Pan, Fu-Ming
We explore novel nanometer-scale gaps with different widths in palladium (Pd) thin-film strips using hydrogen absorption under high- ressure conditions and different temperatures. Both the experimental measurement and numerical calculation are conducted to examine the electron conduction properties of the newly proposed surface conduction electron- emitters (SCEs). It is shown that this novel structure exhibits a high emission efficiency, so that a low turn-on voltage of 40 V for an SCE with a 30 nm nanogap is obtained. A calibrated model is adopted to predict the effects of the emitter thickness and different material work functions on emission current with different width of nanogaps. It is found that the heightened thickness increases the emission current. However, it tends to saturate for smaller nanogaps. The decrement of work function is proportional to the increase in emission current, which is independent of the width of nanogap.
All-optical 2R regenerator using self-seeded laser diode
(2007-11-29)
Chi, Sien
;
Lee, Chien-Chung
;
Chien, Hung-Chang
The present invention is a self-seeded laser diode. The laser diode obtains a gain by itself without using expansive erbium-doped fiber amplifiers. Hence, the cost is reduced and the system is simplified.
Mixed voltage input/output buffer having low-voltage design
(2007-11-29)
Ker, Ming-Dou
;
Chen, Shih-Lun
A mixed-voltage input/output buffer having low-voltage design comprises a pre-driver, a tracking unit, a driving unit, and input/output pad, a floating-well unit and a transporting unit. The pre-driver receives first data signal and enable signal and outputs first and second data voltages. The tracking unit provides Gate-Tracking function. The driving unit couples the pre-driver and the tracking unit for production of a first buffer voltage corresponding to the first data voltage. The input/output pad couples the driving unit to output a first buffer voltage and to receive a second data signal. The output unit is used for outputting a second buffer voltage corresponding to the second data signal. The floating-well unit couples to the driving unit and the input/output pad in order to output first buffer voltage and receive second data signal. The floating-well unit is used for preventing leakage current.
Evidence of tandem repeat and extra thiol-groups resulted in the polymeric formation of bovine haptoglobin: A unique structure of Hp 2-2 phenotype
(2007-11-30)
Lai, Yi An
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Lai, I. Hsiang
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Tseng, Chi Feng
;
Lee, James
;
Mao, Simon J. T.
Human plasma Hp is classified as 1-1, 2-1, and 2-2. They are inherited from two alleles Hp 1 and Hp 2, but there is only Hp 1 in almost all the animal species. Hp 2-2 molecule is extremely large and heterogeneous associated with the development of inflammatory-related diseases. In this study, we expressed entire bovine Hp in E. coli as a alpha beta linear form. Interestingly, the antibodies prepared against this form could recognize the subunit of native Hp. In stead of a complicated column method, the antibody was able to isolate bovine Hp via immunoaffinity and gel-filtration columns. The isolated Hp is polymeric containing two major molecular forms (660 and 730 kDa). Their size and hemoglobin binding complex are significantly larger than that of human Hp 2-2. The amino-acid sequence deducted from the nucleotide sequence is similar to human Hp 2 containing a tandem repeat over the cc chain. Thus, the Hp 2 allele is not unique in human. We also found that there is one additional -SH group (Cys-97) in bovine alpha chain with a total of 8 -SH groups, which may be responsible for the overall polymeric structure that is markedly different from human Hp 2-2. The significance of the finding and its relationship to structural evolution are also discussed.
Innovative three-axial actuator for high-density optical drive
(2007-12-01)
Lan, Yung-Sung
;
Tien, Chung-Hao
;
光電工程學系
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顯示科技研究所
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Department of Photonics
As the density in optical data storage systems increases, a drive capable of tilt control thus becomes necessary in order to improve the tilt margin as the coma aberration is accordingly increased. In this paper, we propose an innovative three-axial actuator based on a traditional four-wire scheme with an additional pair of tilting magnets. The proposed coil-driven servo can independently compensate 1 tilt degree associated with a torque variation of less than 5%. The driving forces of the focusing and tracking are kept constant while the tilt servo is activated.
Photocurrent suppression of transparent organic thin film transistors
(2007-12-01)
Chuang, Chiao-Shun
;
Tsai, Shu-Ting
;
Lin, Yung-Sheng
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Chen, Fang-Chung
;
Shieh, Hang-Ping D.
Organic thin-film transistors (OTFTs) with high transmittance and low photosensitivity have been demonstrated. By using titanium dioxide nanoparticles as the additives in the polymer gate insulators, the level of device photoresponse has been reduced. The device shows simultaneously a high transparence and a minimal threshold voltage shift under white light illumination. It is inferred that the localized energy levels deep in the energy gap of pentacene behave as the recombination centers, enhancing substantially the recombination process in the conducting channel of the OTFFs. Therefore, the electron trapping is relieved and the shift of threshold voltage is reduced upon illumination.
Synthesis, composition optimization, and VUV photoluminescence characterization of (Y,Gd) (V,P) O-4 : Eu3+ as a potential red-emitting plasma-display panel phosphor
(2007-12-01)
Wu, Chia-Chin
;
Cheng, Bing-Ming
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
The synthesis, composition optimization, VUV Photoluminescence (PL) spectra, and optical properties, of (Y, Gd) (V, P)O-4 : Eu3+ phosphors were investigated by synchrotron radiation. The VUV PLE spectra and the correlation among VUV PL intensity, lambda(em), and Eu3+, Gd3+, and P-content were established. The PLE spectral studies showed that (Y, Gd) (V, P)O-4: Eu3+ exhibited significant absorption in the VUV range. The VUV PL intensity was found to enhance with PO43- and Gd3+ -doping. Furthermore, the chromaticity characteristics of (Y, Gd) (V, P)O-4: Eu3+ were also found to be (0.6614, 0.3286) and compared against (Y, Gd)BO3:Eu3+ as a reference. Based on the characterization results, we are currently improving and evaluating the potential application of (Y, Gd) (V, P)O-4: Eu3+ as a new red-emitting PDP phosphor.
具有低電壓元件設計之混合電壓輸入／輸出緩衝器
(2007-12-01)
柯明道
;
陳世倫
一種具有低電壓元件設計之混合電壓輸入/輸出緩衝器,包含預驅動器、循軌單元、驅動單元、輸入/輸出接墊、浮接阱單元及輸送單元;預驅動器,用以接收第一資料信號及致能信號,及輸出第一及第二資料電壓;循軌單元,用以提供閘極循軌功能;驅動單元,耦接預驅動器及循軌單元,用以產生對應於第一資料電壓之第一緩衝電壓;輸入/輸出接墊,耦接至驅動單元,用以輸出第一緩衝電壓及接收第二資料信號;輸送單元,用以輸出對應於第二資料信號之第二緩衝電壓;以及浮接阱單元,耦接至驅動單元及輸入/輸出接墊,用以防止漏電流發生。
應用於信度傳播演算法的自動補償方法與裝置
(2007-12-01)
廖彥欽
;
林建青
;
張錫嘉
;
劉志尉
本發明提供一種用於信度傳播演算法之解碼的自動補償方法,在訊號雜訊比低時仍可有效修正誤差、改進解碼器效能及維持低硬體複雜度,包括:首先使用一最小和(min-sum)演算法來算出多個輸出値,藉以趨近於一信度傳播檢查端之運算結果;接著以一檢查條件來檢查目前解碼疊代次數;及最後若在前一步驟中,該目前解碼疊代次數被判定為一欲修正狀態時,則將該多個輸出値進行一補償程序;其中,係依據該信度傳播檢查端之一輸入値來動態選擇該補償項。本發明亦提供一種用於信度傳播演算法之解碼的自動補償裝置,係利用上述本發明之方法來加以執行的,其具備最小和演算單元及動態量化控制單元等裝置。
Customer order scheduling to minimize the number of late jobs
(2007-12-01)
Lin, B. M. T.
;
Kononov, A. V.
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資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
In the order scheduling problem, every job (order) consists of several tasks (product items), each of which will be processed on a dedicated machine. The completion time of a job is defined as the time at which all its tasks are finished. Minimizing the number of late jobs was known to be strongly NP-hard. In this note, we show that no FPTAS exists for the two-machine, common due date case, unless P = NP. We design a heuristic algorithm and analyze its performance ratio for the unweighted case. An LP-based approximation algorithm is presented for the general multicover problem. The algorithm can be applied to the weighted version of the order scheduling problem with a common due date. (c) 2006 Elsevier B.V. All rights reserved.
Simulation of gear shaving with considerations of cutter assembly errors and machine setting parameters
(2007-12-01)
Hung, Ching-Hua
;
Liu, Jia-Hung
;
Chang, Shinn-Liang
;
Lin, Hung-Jeng
;
機械工程學系
Gear shaving is commonly used as a finishing process for gear manufacturing. The precision of the shaved gear tooth profile is highly dependent on both the parameter adjustments of the shaving machine and the cutter assembly errors. This paper develops the mathematical model of the shaved gear with crowning taking into account the setting parameters of the gear shaving machine and cutter assembly errors. The effects of the parameters on the work gear surface and the tooth lead crowning are also investigated. The results are thought to be relevant to the design, assembly, calibration, and control of a gear shaving machine.
壓電石英感測模組、晶片及系統
(2007-12-01)
黃國華
;
洪孟燕
;
汪孟德
一種壓電石英感測模組、晶片及系統,乃具有多個石英晶體震盪器,且利用多個第一電極分別將同一組的每個石英晶體震盪器加以串聯,再由多個第二電極分別將不同組的石英晶體振盪器之一加以串聯,如此構成的連接電路可將每一個石英晶體震盪器作定位,而可單獨啓動每一個石英晶體震盪器,藉以達到多樣品的即時偵測。
Synchronization of complex chaotic systems in series expansion form
(2007-12-01)
Ge, Zheng-Ming
;
Yang, Cheng-Hsiung
;
機械工程學系
;
Department of Mechanical Engineering
This paper studies the synchronization of complex chaotic systems in series expansion form by Lyapunov asymptotical stability theorem. A sufficient condition is given for the asymptotical stability of an error dynamics, and is applied to guiding the design of the secure communication. Finally, numerical results are studied for the Quantum-CNN oscillators synchronizing with unidirectional/bidirectional linear coupling to show the effectiveness of the proposed synchronization strategy. (c) 2006 Elsevier Ltd. All rights reserved.
一種由微囊胞聚集體所構成的支架及其製造方法
(2007-12-01)
陳三元
;
劉澤英
;
劉典謨
一種由微囊胞聚集體所構成的組織工程支架及其製造方法,藉由乳化製程或是微脂體製程來形成囊胞,並透過控制材料特性及乳化條件,配合支架成形製程,使微囊胞自我堆積聚集組裝形成緊密結構,並可做為組織或細胞貼附、成長及分化之基底,還可以透過微囊胞預先包覆組織或細胞貼附、成長及分化過程中所需的藥物分子,使之同時發揮基底結構及藥物儲槽的雙重角色,並透過微囊胞特性近一步控制藥物釋放速率,達到藥物程序式釋放、協同釋放與穩定釋放的功能,且不易破壞藥物活性,並應用在組織工程及細胞培養的生醫元件上。