Browsing by Issue Date, starting with "2005-09-05"

Now showing 1 - 20 of 66034

The approximability of the weighted Hamiltonian path completion problem on a tree
(2005-09-05)
Wu, Q
;
Lu, CL
;
Lee, RCT
;
生物科技學系
;
Department of Biological Science and Technology
Given a graph, the Hamiltonian path completion problem is to find an augmenting edge set such that the augmented graph has a Hamiltonian path. In this paper, we show that the Hamiltonian path completion problem will unlikely have any constant ratio approximation algorithm unless NP = P. This problem remains hard to approximate even when the given subgraph is a tree. Moreover, if the edge weights are restricted to be either 1 or 2, the Hamiltonian path completion problem on a tree is still NP-hard. Then it is observed that this problem is strongly NP-hard, so it does not have any fully polynomial-time approximation scheme (FPTAS) unless NP = P. When the given tree is a k-tree, we give an approximation algorithm with performance ratio 1.5. (c) 2005 Elsevier B.V. All rights reserved.
Ultrahigh supermode noise suppressing ratio of a semiconductor optical amplifier filtered harmonically mode-locked Erbium-doped fiber laser
(2005-09-05)
Lin, GR
;
Wu, MC
;
Chang, YC
;
Pan, CL
;
光電工程學系
The supermode noise suppressing ratio (SMSR) and the phase noise of a harmonically mode-locked Erbium-doped fiber laser (HML-EDFL) with an intra-cavity semiconductor optical amplifier (SOA) and an optical band-pass filter (OBPF) are improved and compared with a state-of-the-art Fabry-Perot laser diode (FPLD) injection-mode-locked EDFL. By driving the intra-cavity SOA based high-pass filter at unitary gain condition, the SMSR of the HML-EDFL is enhanced to 82 dB at the cost of degrading phase noise, increasing jitter, and broadened pulsewidth. The adding of OBPF further improves the SMSR, pulsewidth, phase noise, and jitter of the SOA-filtered HML-EDFL to 90 dB, 42 ps, -112 dBc/Hz, and 0.7 ps, respectively. The ultrahigh SMSR of the SOA-filtered HML-EDFL can compete with that of the FPLD injection-mode-locked EDFL without sacrificing its pulsewidth and jitter performances. (c) 2005 Optical Society of America
Stabilized and wavelength-tunable S-Band erbium-doped fiber ring laser with single-longitudinal-mode operation
(2005-09-05)
Yeh, CH
;
Lin, MC
;
Chi, S
;
物理研究所
;
光電工程學系
A stable and wavelength-tunable S-band erbium-doped fiber (EDF) ring laser with single-longitudinal-mode oscillation over the operating range of 1480.6 to 1522.9 nm is proposed and experimentally demonstrated. The proposed ring laser provides a fine mode restriction and guarantees the single- frequency operation based on a shorter length EDF serving as auto-tracking filter. Therefore, the performances of output power of > 10 dBm, power stability of < 0.05 dB, central wavelength variation of < 0.01 nm, and side- mode suppression ratio (SMSR) of > 49.1 dB have been experimentally demonstrated in the operating range of 1488.7 to 1505.7 nm. (c) 2005 Optical Society of America.
親子水墨創作教學大家都是藝術家
(2005-09-05)
本報訊
An efficient local fundamental-mode cutoff for thermo-optic tunable Er3+-doped fiber ring laser
(2005-09-05)
Chen, NK
;
Chi, S
;
Tseng, SM
;
光電工程學系
;
Department of Photonics
We demonstrate a continuously tunable Er3+-doped fiber laser by incorporating a short-pass filter, which provides a wideband tunable fundamental-mode cutoff with high rejection efficiency (> 45 dB/cm) at long wavelengths, into a ring resonator. The tunable short-pass filter locally suppresses the gain profile of the Er3+-doped fiber at long wavelengths and makes the lasing wavelength continuously move toward short wavelengths when optical polymer is cooling down. The tuning efficiency, tuning range, signal-ASE-ratio, and FWHM linewidth of the laser are 7.65 nm/degrees C, 26 nm (1569.8 similar to 1595.8 nm), 40 dB, and 0.5 nm, respectively.
[ADJUSTABLE COLLIMATOR AND SPUTTERING APPARATUS WITH THE SAME]
(2005-09-08)
Lee, Cheng-Shih
;
Chang, Edward Yi
An adjustable collimator and a sputtering apparatus with the same are provided. The adjustable collimator comprises an adjustable main body, first and second collimating elements. The adjustable main body has an interior space, a top portion, a bottom portion and an adjuster between the top portion and the bottom portion. The adjuster is adapted for adjusting a relative distance between the top portion and the bottom portion. A first collimating element fixed inside the interior space of the top portion in a manner to move with the top portion and a second collimating element fixed inside the interior space of the bottom portion to move with the bottom portion. When the adjustable collimator applies to sputtering apparatus, it can easily control the incident angel of the molecule of the sputtering material by adjusting a relative distance between the top and bottom portion.
Process for fabricating supersphere solid immersion lens
(2005-09-08)
Hsu, Wensyang
;
Sun, Yi-Ting
The present invention relates to process for fabricating supersphere solid immersion lens (SSIL). The procedure of the present invention comprises the steps of: firstly, coating a positive photoresist layer on a substrate, followed by first exposure and second exposure with different exposure dose separately by first mask and second mask to form the positive photoresist structure with different dimensions and depths. The first exposure dose is supplied enough to make sure the patterns of the first mask can be observed on the positive photoresist layer during the alignment of the second exposure process. And the following reflow process forms a supersphere solid immersion lens (SSIL) structure.
Detection of vibration-rotational band 5-0 of (CO)-C-12-O-16 X (1)Sigma(+) with cavity ringdown absorption near 0.96 mu m
(2005-09-08)
Chung, CY
;
Ogilvie, JF
;
Lee, YP
;
應用化學系
;
應用化學系分子科學碩博班
We have recorded extremely weak absorption in the overtone band 5-0 of (CO)-C-12-O-16 X (1)Sigma(+) near 0.96 mu m with cavity ringdown spectroscopy; the light source was a Raman-shifted dye laser pumped with a frequency doubled Nd:YAG laser. This band shows lines in branch P to be much more intense than corresponding lines in branch R, in contrast to all lower overtone bands v-0 (v = 1-4). This reversal in relative intensity is explained quantitatively in terms of a radial function for the electric dipolar moment of CO. We have estimated absorption line strengths for P-3-P-18 in band 5-0 of (CO)-C-12-O-16; these strengths are consistent with a pure vibrational matrix element (5 vertical bar p(x)vertical bar 0) = (3.6 +/- 0.3) x 10(-36) C m of the electric dipolar moment p(x), a Herman-Wallis coefficient C-0(5) of about -0.1, and a band strength of (5.1 +/- 1.3) x 10(-29) m at 293 K.
Microelectro mechanical system for magneto-optic data storage apparatus
(2005-09-08)
Hsu, Wensyang
;
Shieh, Han-Ping
;
Sun, Yi Ting
The present invention relates to a Microelectro mechanical system structure. More specifically the invention relates to utilize a sacrificial layer to fabricate an air bearing structure, followed by forming an aperture, and reducing the aperture to nano-scale by electroplating. And then, by using of two thick film photoresist films for twice electroplating fabrication, for fabricate metal microcoils having high aspect ratio structure and interconnection metal line, to achieve efficiencies of utilizing area and reducing resistance. Moreover, proceed lithography depends on different portions and exposure dose. Then form a single photoresist film to have a specific dimension and thickness structure, finally, by using reflow process, forming a magneto-optic (MO) pickup head comprises of Supersphere Solid Immersion Lens (SSIL), nano-aperture, microcoils and air bearing by using an integrated fabrication, with advantages such as no high cost device and precise apparatus are required in the process of fabrication, mass production in batch fabrication, without step of assembly, for high-density data storage and rewritable record.
Architecture for stack robust fine granularity scalability
(2005-09-08)
Huang, Hsiang-Chun
;
Wang, Chung-Neng
;
Chiang, Tihao
;
Hang, Hsuch-Ming
The present invention relates to an architecture for stack robust fine granularity scalability (SRFGS), more particularly, SRFGS providing simultaneously temporal scalability and SNR scalability. SRFGS first simplifies the RFGS temporal prediction architecture and then generalizes the prediction concept as the following: the quantization error of the previous layer can be inter-predicted by the reconstructed image in the previous time instance of the same layer. With this concept, the RFGS architecture can be extended to multiple layers that forming a stack to improve the temporal prediction efficiency. SRFGS can be optimized at several operating points to fit the requirements of various applications while the fine granularity and error robustness of RFGS are still remained. The experiment results show that SRFGS can improve the performance of RFGS by 0.4 to 3.0 dB in PSNR.
閒事咖啡觀音
(2005-09-09)
管管
垂直入射型折射率測量裝置
(2005-09-11)
蘇德欽
;
許正治
;
陳坤煌
本發明係揭露一種垂直入射型折射率測量裝置，其係將由左旋偏光及右旋偏光間有頻差的旋光外差光源所發出來的光線，經一偏光保持光纖將光入射於一測試模組。一檢偏板抽出經高反射面鏡及待測物垂直反射而回光束中相同的偏極光成份，並使之干涉；其干涉信號由光偵測器測得。再利用一相位計分析光偵測器所得的訊號可得到經由待測物所引進的相位差，此相位差與待測物的折射率有關；最後再根據瓊斯計算法(Jones calculus)與斯涅耳方程式所推演出的公式以及由外差干涉術所測出的相位差變化，便可計算出待測物的折射率。由於本發明無須使用造成全反射的稜鏡，所以對於待測物的量測範圍將不會受探頭折射率的限制，故量測範圍較為廣泛並以垂直入射待測物，所以裝置及操作上都更為簡單。
太陽能光主動元件
(2005-09-11)
祁甡
;
陳南光
;
施宙聰
本發明係提供一種太陽能光主動元件，係利用太陽能矽晶片板上之全像天線光柵來選擇特定繞射波長並以近似垂直耦合的方式將泵浦波長耦合並匯聚藉此激發光增益介質，使之產生光放大或雷射的效果，其係適用於地面之無線光通訊以及衛星光通訊，無需很大的體積，對於物體的表面形狀更有彈性(即使大樓的頂樓或外牆玻璃表面均可製作該全像天線光柵)，若在衛星上則可依附於太陽能電池板上，並產生極高的放大增益，不但可以減少衛星光通訊對電力的依賴，更可滿足特殊衛星快速傳輸大量資料的目的。
Method for detection of manufacture defects
(2005-09-13)
Tseng
;
Shian-Shyong
;
Chen
;
Wei-Chou
;
Wang
A novel method for detection of manufacture defects is disclosed. The invented method is designed to discover root cause machine sets that cause defects in product manufactured in a process wherein a plurality of machines is involved. The method includes obtaining manufacture data that relate to manufacture of products in the manufacture process, generating a candidate list of machine set by analyzing the manufacture data wherein the machine set includes machines relative to defects in the products, and identifying root cause machine sets from the list of machine set wherein the root cause machine sets include machines highly related to the defects.
Method for fabricating nanometer gate in semiconductor device using thermally reflowed resist technology
(2005-09-13)
Chang
;
Edward Y.
;
Lee
;
Huang-Ming
The invention relates to a method for fabricating nanometer gate semiconductor device using thermally reflowed photoresist technology, comprising steps of (i) spin-coating two layers of photoresists on a substrate, where a bottom layer of photoresist is a polymeric photoresist having a lower sensitivity and a higher resolution, and a top layer of photoresist, is another polymeric photoresist having a higher sensitivity and a lower resolution, with respect to the electron beam; (ii) heating the photoresists for curing by way of using a hotplate; (iii) using photolithography in an electron beam direct writing manner to expose a pattern on the photoresists for forming a gate; (iv) using a developer and an etchant for developing and etching to form a recess on the gate; (v) plating a metallic layer on the recess of the gate using an electron gun evaporation technique; and (vi) removing the photoresists to obtain the gate, characterized in that after the etching of the recess of the gate, the photoresists are reflowed by using a hot plate heating manner within a predetermined period of time and temperature, such that the recess of the gate is formed with a nanometer-sized width.
Efficient periodically poled stoichiometric lithium tantalate optical parametric oscillator for the visible to near-infrared region
(2005-09-15)
Tu, SY
;
Kung, AH
;
Gao, ZD
;
Zhu, SN
;
光電工程學系
A compact, efficient optical parametric oscillator (OPO) for the visible to near-infrared region based on periodically poled stoichiometric lithium tantalate pumped by a frequency-doubled multikilohertz Q-switched Nd:YAG laser is demonstrated. Up to 61% photon conversion with a 71% slope efficiency for photon conversion from 532 nm to the signal radiation was measured. We observed that the efficient conversion diminished the potential for photorefractive damage induced by the 532 am radiation in the crystal and made sustained operation of the OPO device possible. (c) 2005 Optical Society of America.
管管作品三首
(2005-09-15)
管管
管管作品三首
(2005-09-15)
管管
管管作品三首
(2005-09-15)
管管
Nucleation and growth behavior of well-aligned ZnO nanorods on organic substrates in aqueous solutions
(2005-09-15)
Lin, CC
;
Chen, SY
;
Cheng, SY
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A low-temperature synthetic route was used to prepare well-aligned arrays of oriented ZnO nanorods on organic substrates coated with polystyrene beads (PS) in an aqueous solution. The corresponding growth behavior and photoluminescence properties of ZnO nanorods were analyzed. It was found that the ZnO nanorods are initially nucleated from the ZnO monolayer under the concave regions of the PS layers and preferentially grown along [0 0 0 1] direction. High-resolution transmission electron microscopy (HRTEM) observation reveals that the ZnO nanorods tend to coalesce together with other adjacent nanorods to form a larger ZnO crystal in the later growth stage. The room-temperature photoluminescence spectra demonstrate that a stronger ultraviolet (UV) emission with a broad yellow emission around 575 nm was observed for the ZnO nanorods grown on the organic substrates and the relative intensity ratio of ultraviolet emission to yellow emission depends on the growth periods of time. This simple approach demonstrates great potential for optoelectronic devices because it can produce large-scale highly well-aligned ZnO nanorods on the flexible organic substrates at lower temperatures. (c) 2005 Elsevier B.V. All rights reserved.