Browsing by Issue Date, starting with "2008-05-26"

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Glass material model for the forming stage of the glass molding process
(2008-05-26)
Tsai, Yu-Chung
;
Hung, Chinghua
;
Hung, Jung-Chung
;
機械工程學系
;
Department of Mechanical Engineering
The aim of this research is to obtain an accurate material model for glass that can be used in finite element (FE) analysis of the glass molding process. A thorough understanding of the deformation behavior of the glass specimens was acquired by performing uniaxial compression tests. The elasto-viscoplastic model was utilized for the glass material at the molding temperature to construct the FE model, and a suitable set of parameters for this material model was verified by comparing the simulation results to the experimental data. As a result, the feasibility of the elasto-viscoplastic model for glass at the molding temperature was confirmed; this material model can be used in FE analysis of the prediction and modification of properties of the final lens products. (C) 2008 Published by Elsevier B.V.
The experimental study on the defects occurrence of SL mold in injection molding
(2008-05-26)
An, Chao-Chyun
;
Chen, Ren-Haw
;
機械工程學系
;
Department of Mechanical Engineering
Past experience has shown that the defects occurrence in injection-molded parts of metal mold included weld line, flow mark and solid skin. In this study, a thin wall cavity is designed as flow path for plastic injection mold. The injection molding tests were performed by using metal mold and stereolithography (SL) mold to compare with the flow behavior and defects occurrence of flat parts. The experiments were performed with various process parameters to investigate the defects occurrence in the injection-molded parts. The experimental results showed that defects occurrence has close relation with injection speeds and mold temperatures. Flow marks of SL mold occur more easily when the mold temperature and the injection speed are low. Moreover, the injection-molded parts were examined whether the surface defects (flow mark and weld line) occurred and analyzed as the reference for the future SL mold design. (C) 2007 Elsevier B.V. All rights reserved.
Prediction of slug carry-up by the punch in blanking by air-blow of the slug
(2008-05-26)
Hsu, R. Q.
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Chang, J. R.
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Liang, D. L.
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機械工程學系
;
Department of Mechanical Engineering
Blanking is one of the press working operations most often encountered in sheet-metal processing. The punched part or slug which should fall down through the die cavity was occasionally brought upward by the punch and dropped on the strip stock which will hinder the following blanking operation. Though there are many ways to reduce this problem, however, this phenomenon still exists when stamping a very thin gauge strip in a highspeed press. Methods which can help us predict the occurrence of the slug suck-up by the punch in blanking are thus important. In this study, a prediction method is proposed for the occurrence of the phenomenon by air-blow of the slug. Parameters like material tensile strength, punch/die clearances, punch chamfer degree, punch corner radius were considered in organizing the experiment plans. The results showed that the slug carry-up forces measured from direct air-blow of the slug can be adopted as a criterion for the occurrence of the phenomenon. The best and worst parameter combinations were also identified by this method. (C) 2008 Published by Elsevier B.V.
Diode-pumped multi-frequency Q-switched laser with intracavity cascade Raman emission
(2008-05-26)
Chang, Y. T.
;
Huang, Y. P.
;
Su, K. W.
;
Chen, Y. F.
;
電子物理學系
A diode-pumped actively Q-switched mixed Nd:Y0.3Gd0.7VO4 laser with an intracavity KTP crystal is developed to produce cascade SRS emission up to the fourth order. With an incident pump power of 14 W and a repetition rate of 50 kHz, the average output powers at the first, second, third and fourth Stokes modes are approximately 0.05 W, 0.61 W, 0.25 W, and 0.11 W, respectively. The maximum peak power is greater than 2 kW. (C) 2008 Optical Society of America.
Observation of transition state in Raman triggered oxidation of chloroform in the ground state by real-time vibrational spectroscopy
(2008-05-27)
Iwakura, Izumi
;
Yabushita, Atsushi
;
Kobayashi, Takayoshi
;
電子物理學系
;
Department of Electrophysics
A transition state (TS) during Raman triggered oxidation of chloroform was directly observed by ultrafast spectroscopy using broadband visible sub-5 fs pulses. Changes in the molecular structures including the TSs along the reaction pathways were detected by the time-dependent instantaneous frequencies of vibrational modes. The Raman triggered oxidation of chloroform was found to be initiated by the excitation of vibrational levels through stimulated Raman processes involving the ground-state chloroform oxygen complex. (C) 2008 Published by Elsevier B.V.
Infrared absorption spectra of vinyl radicals isolated in solid Ne
(2008-05-28)
Wu, Yu-Jong
;
Lin, Meng-Yeh
;
Cheng, Bing-Ming
;
Chen, Hui-Fen
;
Lee, Yuan-Pern
Irradiation of samples of solid Ne near 3.0 K containing ethene (C(2)H(4)) with vacuum ultraviolet radiation at 120 nm from synchrotron yielded new spectral lines at 3141.0, 2953.6, 2911.5, 1357.4, 677.1, 895.3, and 857.0 cm(-1). These features are assigned to alpha-CH stretching (nu(1)), CH(2) antisymmetric stretching (nu(2)), CH(2) symmetric stretching (nu(3)), CH(2)-bending (nu(5)), HCCH cis bending (nu(7)), CH(2) out-of-plane bending (nu(8)), and alpha-CH out-of-plane bending (nu(9)) modes of C(2)H(3), respectively, based on results of (13)C- and D-isotopic experiments and quantum-chemical calculations. These calculations using density-functional theory (B3LYP and PW91PW91/aug-cc-pVTZ) predict vibrational wavenumbers, IR intensities, and isotopic ratios of vinyl radical that agree satisfactorily with our experimental results. (C) 2008 American Institute of Physics.
Coupling of polarization and spatial degrees of freedom of highly divergent emission in broad-area square vertical-cavity surface-emitting lasers
(2008-05-30)
Babushkin, I. V.
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Schulz-Ruhtenberg, M.
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Loiko, N. A.
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Huang, K. F.
;
Ackemann, T.
The polarization of highly divergent modes of broad-area square vertical-cavity surface-emitting lasers is shown to be only marginally affected by material anisotropies but determined by an interplay of the polarization properties of the Bragg cavity mirrors and of the transverse boundary conditions. This leads to a locking of the polarization direction to the boundaries and its indeterminacy for wave vectors oriented along the diagonal. We point out a non-Poissonian character of nearest-neighbor frequency spacing distribution and the impossibility of single-wave number solutions.
Ranking decision alternatives by integrated DEA, AHP and Gower plot techniques
(2008-06-01)
Li, Han-Lin
;
Ma, Li-Ching
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
Data Envelop Analysis (DEA) and Analytic Hierarchy Process (AHP) are widely used methods in ranking decision alternatives. However, current DEA models are difficult to discriminate decision-making units through articulating the decision makers' preferences. While AHP and Gower plot models have to specify complete pairwise preferences without providing assisting information. This study develops an iterative method of ranking decision alternatives by integrating DEA, AHP and Gower plot techniques. The developed method first utilizes a modified DEA model to narrow the ranges of a decision maker's preferences. Then, the tentative ranks of the decision alternatives, computed by embedding the decision maker's preferences, are depicted via Gower plots to illustrate the cardinal and ordinal inconsistencies of these preferences. The decision maker then adjusts the preferences iteratively until the inconsistencies are within the tolerance.
T allele for VEGF-460 gene polymorphism at 5 '-untranslated region is associated with higher susceptibility of leiomyoma
(2008-06-01)
Hsieh, Yao-Yuan
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Chang, Chi-Chen
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Tsai, Fuu-Jen
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Lin, Cheng-Chieh
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Tsai, Chang-Hai
Vascular endothelial growth factor (VEGF) is a regulator of angiogenesis and a mediator of sex steroid-induced cell growth and differentiation. We aimed to investigate if VEGF gene 5'-UTR -460 polymorphism could be used as markers of susceptibility in leiomyoma. Women were divided into two groups: (1) leiomyoma (n=159); (2) nonleiomyoma groups (n=131). VEGF gene-460 polymorphism were detected by polymerase chain reaction and BstUI restriction enzyme analysis. Genotypes and allelic frequencies between both groups were compared. We noted that the proportions of different VEGF polymorphisms in both groups were significantly different. Proportions of cuttable (C) homozygote/heterozygote/uncuttable (T) homozygote for VEGF in both groups were: (1) 0/32/68% and (2) 0/63/37%. Higher percentage of T homozygote and T allele presented in the leiomyoma population. Proportions of C/T alleles in both groups were: (1) 16/84% and (2) 32/68%. We concluded that T homozygotes and T allele of VEGF gene-460 polymorphism are associated with higher risk of leiomyoma development. Heterozygotes and C allele are related with lower risk of leiomyoma formation VEGF gene polymorphism likely contributes to the pathogenesis of leiomyoma.
疊在歷史皺折裡的追悼：《被遺忘的一九三七》觀後感（影評）
(國立陽明交通大學出版社, 2008-06-01)
吳哲良
A recursive method for the F-policy G/M/1/K queueing system with an exponential startup time
(2008-06-01)
Wang, Kuo-Hsiung
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Kuo, Ching-Chang
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Pearn, W. L.
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工業工程與管理學系
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Department of Industrial Engineering and Management
This paper deals with the optimal control of a finite capacity G/M/1 queueing system combined the F-policy and an exponential startup time before start allowing customers in the system. The F-policy queueing problem investigates the most common issue of controlling arrival to a queueing system. We provide a recursive method, using the supplementary variable technique and treating the supplementary variable as the remaining interarrival time, to develop the steady-state probability distribution of the number of customers in the system. We illustrate a recursive method by presenting three simple examples for exponential, 3-stage Erlang, and deterministic interarrival time distributions, respectively. A cost model is developed to determine the optimal management F-policy at minimum cost. We use an efficient Maple computer program to determine the optimal operating F-policy and some system performance measures. Sensitivity analysis is also studied. (c) 2007 Elsevier Inc. All rights reserved.
媒體亂象全民同監督
(2008-06-01)
鄭瑋津
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Department of Communication and Technology
;
傳播與科技學系
記者
Psychometric analysis of the short-form UCLA Loneliness Scale (ULS-8) in Taiwanese undergraduate students
(2008-06-01)
Wu, Chia-Huei
;
Yao, Grace
;
經營管理研究所
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Institute of Business and Management
The main purpose of this study was to validate the short-form of the UCLA Loneliness Scale (ULS-8; Hays & DiMatteo, 1987) in Taiwanese undergraduate students. A total of 130 undergraduate students participated in this study. Participants completed the ULS-8 in addition to measures of life satisfaction, social support, and adult attachment style. Result of confirmatory factor analysis supported the one-factor model of the ULS-8 with adequate values of various fit indices, revealing that the 8 items of the scale were homogeneous for measuring loneliness. In addition, the ULS-8 had a negative relationship with life satisfaction, and social support; and a positive one with anxiety and avoidant attachment tendency. All the findings showed that the ULS-8 was an adequate short-form measure of loneliness. (C) 2008 Elsevier Ltd. All rights reserved.
The effect of pre-aging on the electromigration of flip-chip SnAg solder joints
(2008-06-01)
Yang, Po-Chun
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Kuo, Chien-Chih
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Chen, Chih
;
材料科學與工程學系
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Department of Materials Science and Engineering
The effect of pre-aging on electromigration is investigated in this study using flip-chip SnAg solder joints. The solder joints were pre-aged at 170 degrees C for 1 h, 3 h, 5 h, 10 h, 25 h, and 50 h, and then they were subjected to electromigration tests of 0.9 A at 150 degrees C. It was found that the average failure time increased about three times when the joints were pre-aged for 3 h to 25 h. But it decreased when the joints were over-aged. It is proposed that the major contributor to the prolonged failure time may be the densification of the nickel and copper under-bump metallization (UBM) and the solder due to the aging treatment. The pre-aging treatment at 170 degrees C may stabilize the microstructure of the solder. The vacancies in the solder were annihilated during the heat treatment, causing a slower diffusion rate. In addition, the UBM structure became denser after the pre-aging process. Thus, the denser UBM structure may lead to slower consumption rates of the nickel and copper layers, resulting in the enhancement of electromigration resistance.
KTV文化台灣社會縮影
(2008-06-01)
謝甄芳
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Department of Communication and Technology
;
傳播與科技學系
台灣的KTV文化
The sea of learning: Mobility and identity in nineteenth-century Guangzhou
(2008-06-01)
Lee, Thomas H. C.
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交大名義發表
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National Chiao Tung University
Whole-brain functional magnetic resonance imaging mapping of acute nociceptive responses induced by formalin in rats using atlas registration-based event-related analysis
(2008-06-01)
Shih, Yen-Yu I.
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Chen, You-Yin
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Chen, Chiao-Chi V.
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Chen, Jyh-Cheng
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Chang, Chen
Nociceptive neuronal activation in subcortical regions has not been well investigated in functional magnetic resonance imaging (fMRI) studies. The present report aimed to use the blood oxygenation level-dependent (BOLD) fMRI technique to map nociceptive responses in both subcortical and cortical regions by employing a refined data processing method, the atlas registration-based event-related (ARBER) analysis technique. During fMRI acquisition, 5% formalin (50 mu l) was injected into the left hindpaw to induce nociception. ARBER was then used to normalize the data among rats, and images were analyzed using automatic selection of the atlas-based region of interest. It was found that formalin-induced nociceptive processing increased BOLD signals in both cortical and subcortical regions. The cortical activation was distributed over the cingulate, motor, somatosensory, insular, and visual cortices, and the subcortical activation involved the caudate putamen, hippocampus, periaqueductal gray, superior colliculus, thalamus, and hypothalamus. With the aid of ARBER, the present study revealed a detailed activation pattern that possibly indicated the recruitment of various parts of the nociceptive system. The results also demonstrated the utilization of ARBER in establishing an fMRI-based whole-brain nociceptive map. The formalin induced nociceptive images may serve as a template of central nociceptive responses, which can facilitate the future use of fIVIRI in evaluation of new drugs and preclinical therapies for pain. (c) 2008 Wiley-Liss, Inc.
Education system integration in cross-disciplinary with colleges - Virtual biomedical instrument (VBI) for example
(2008-06-01)
Hsiao, Tzu-Chien
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Chang, Chia-Chi
;
Liu, Chien-Sheng
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Lin, Chii-Wann
;
Wang, Chih-Yu
Due to the rapid development of computer science, software, and biomedical engineering, many clinical diagnosis instruments and control system improved accordingly. The minimization and practicality of sensors, as well as the efficiency and stability of computers make simulation control system in medical instruments become the most important part of developing items. The relevant subject of course, virtual biomedical instrumentations (VBI), which combined with computer science, electrical engineering, and medical science, has become a major developing course in biomedical education. Cross-disciplinary research needs experts in different areas and most cross-disciplinary schools cannot afford it. So it requires integration and cooperation between schools. To address this issue, a graduated course has been designed to provide an opportunity for all professions in each field to discuss and share their resources on an e-learning platform. With the progress of the project, VBI course integrates biomedical education resources from north to south colleges to reduce the request of manpower for cross-disciplinary course of biomedical. In addition, VBI courses initiate the cooperation between academic community and industry.
ESD protection design with on-chip ESD bus and high-voltage-tolerant ESD clamp circuit for mixed-voltage I/O buffers
(2008-06-01)
Ker, Ming-Dou
;
Chang, Wei-Jen
;
電機學院
;
College of Electrical and Computer Engineering
Considering gate-oxide reliability, a new electrostatic discharge (ESD) protection scheme with an on-chip ESD bus (ESD _ BUS) and a high-voltage-tolerant ESD clamp circuit for 1.2/2.5 V mixed-voltage I/O interfaces is proposed. The devices used in the high-voltage-tolerant ESD clamp circuit are all 1.2 V low-voltage N- and P-type MOS devices that can be safely operated tinder the 2.5-V bias conditions without suffering from the gate-oxide reliability issue. The four-mode (positive-to-V-SS, negative-to-V-SS, positive-to-V-DD, and negative-to-V-DD) ESD stresses on the mixed-voltage I/O pad and pin-to-pin ESD stresses can be effectively discharged by the proposed ESD protection scheme. The experimental results verified in a 0.13-mu m CMOS process have confirmed that the proposed new ESD protection scheme has high human-body model (HBM) and machine-model (MM) ESD robustness with a fast turn-on speed. The proposed new ESD protection scheme, which is designed with only low-voltage devices, is an excellent and cost-efficient solution to protect mixed-voltage I/O interfaces.
A high performance spread spectrum clock generator using two-point modulation scheme
(2008-06-01)
Kao, Yao-Huang
;
Hsieh, Yi-Bin
;
傳播研究所
;
Institute of Communication Studies
A new spread spectrum clock generator (SSCG) using two-point delta-sigma modulation is presented in this paper. Not only the divider is varied, but also the voltage controlled oscillator is modulated. This technique can enhance the modulation bandwidth so that the effect of EMI suppression is improved with lower order Sigma Delta modulator and can simultaneously optimize the jitter and the modulation profile. In addition, the method of two-path is applied to the loop filter to reduce the capacitance value such that the total integration can be achieved. The proposed SSCG has been fabricated in a 0.35 mu m CMOS process. The clock of 400 MHz with center spread ratios of 1.25% and 2.5% are verified. The peak EMI reduction is 19.73 dB for the case of 2.5%. The size of chip area is 0.90 X 0.89 mm(2).