Browsing by Issue Date, starting with "2011-04-25"

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Accurate vibration analysis of thick, cracked rectangular plates
(2011-04-25)
Huang, C. S.
;
Leissa, A. W.
;
Li, R. S.
;
土木工程學系
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Department of Civil Engineering
This work applies the Ritz method to accurately determine the frequencies and nodal patterns of thick, cracked rectangular plates analyzed using Mindlin plate theory. Two types of cracked configuration are considered, namely, side crack and internal crack. To enhance the capabilities of the Ritz method in dealing with cracked plates, new sets of admissible functions are proposed to represent the behaviors of true solutions along the crack. The proposed admissible functions appropriately describe the stress singularity behaviors around a crack tip and the discontinuities of transverse displacement and bending rotations across the crack. The present solutions monotonically converge to the exact frequencies as upper bounds when the number of admissible functions increases. The validity and accuracy of the present solutions are confirmed through comprehensive convergence studies and comparison with the published results based on the classical thin plate theory. The proposed approach is further employed to investigate the effects of the length, location, and orientation of crack on frequencies and nodal patterns of simply supported and cantilevered cracked rectangular plates. The results shown are the first ones available in the published literature. (C) 2010 Elsevier Ltd. All rights reserved.
魯迅的復仇哲學
(2011-04-27)
倪偉
;
開放教育推動中心
;
Open Education Office
課程首頁本課程是由交通大學新文藝復興閱讀計畫提供。 96 年 8 月當各大學紛紛摩拳擦掌準備迎接新生的同時，交通大學校長吳重雨則因為一則來自於七月份泰晤士報，有關於英國首相布朗公布其夏日讀書清單的新聞中，看到了他對知識的尊重。在這同時，吳重雨校長也思考著，要如何為學生準備追求知識的環境和激發他們對知識的尊重與喜愛。台積電張忠謀董事長曾陳述他 18 歲進入哈佛那一年，博覽文史哲理工經典群籍，至此奠定了他求知的基礎，並借海明威名言，將其改為「哈佛這一年為人生可帶走的盛宴。」吳重雨校長以張董事長的學習為借鏡，認為學生固然能藉由自我閱讀的方式學習到豐沛的知識，但透過名人、大師親臨現場地介紹經典書籍，更能加深學子們對於書籍的認識與興趣，這也是「新文藝復興閱讀計劃」 ( 以下簡稱 : 「經典名著選讀」 ) 活動展開籌劃的緣由。於是，吳重雨校長便積極敦請「交大通識教育委員會」，接手籌備本計劃的相關活動，而該中心也成為實際施行本計畫的策動、開課以及認證單位。至此，期許交大學子藉由閱讀、聽講來提昇人文素養、開拓視野的「新文藝復興閱讀計劃」，就此展開。
ELECTRO-OPTICAL DEVICE
(2011-04-28)
Fan Shih-Kang
;
Chiu Cheng-Pu
An electro-optical device includes a body of fluid, a lower conductor layer disposed below the body of fluid, and a dielectric layer disposed between the body of fluid and the lower conductor layer, connected to the lower conductor layer and supporting the body of fluid. The dielectric layer includes a matrix and a liquid crystal material disposed in the matrix and including liquid crystal molecules. The dielectric layer has a segment disposed adjacent to the fluid. When the segment of the dielectric layer is exposed to an electric field, the body of fluid undergoes electrowetting or dielectrophoresis mechanism, and the orientation of the liquid crystal molecules that are disposed in the segment of the dielectric layer is changed.
Development trends for insertion devices of future synchrotron light sources
(2011-04-28)
Hwang, C. S.
;
Jan, J. C.
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Chang, C. S.
;
Chen, S. D.
;
Chang, C. H.
The in-vacuum undulator with a permanent magnet at room temperature is a mature technology and is widely used; with a short period length in a medium-energy facility, it can enhance photon brilliance in the hard x-ray region. A cryogenic permanent magnet has been investigated as an in-vacuum undulator; this undulator will become the best prospective device to satisfy the requirements of a photon source with great brilliance in the hard x-ray region. For the further hard x-ray region, a superconducting wiggler can provide great flux with a continuous spectrum, whereas a superconducting undulator will provide great brilliance with a discrete spectrum. High-temperature superconducting wires are highly promising for use in the development of superconducting undulators; unique algorithms for their development with an extremely short period in a small-magnet gap have been devised. Some out-of-vacuum planar undulators with special functions must also be fabricated to enable diverse applications in various light-source facilities. This article describes current and future developments for insertion devices in storage-ring and free-electron-laser facilities and discusses their feasibility for use therein.
Neutral dissociation of hydrogen molecules in a strong laser field through superexcited states
(2011-04-28)
Azarm, A.
;
Song, D.
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Liu, K.
;
Hosseini, S.
;
Teranishi, Y.
Fragmentation of hydrogen molecules in a strong laser field is studied experimentally and theoretically. Balmer lines (n -> 2) from hydrogen atoms are observed up to n = 14. The emission intensity of the two strongest Balmer lines versus laser intensity in a log-log plot gives a slope of more than 11. This indicates that some high-lying states in the continuum are excited resulting in neutral dissociation. Adapting Rydberg state approximation, the potential energy curves of superexcited states of hydrogen are plotted. Semi-empirical calculation confirms dissociation through these superexcited states. The upper limit of the lifetime of the superexcited states is obtained by an ultrafast pump and probe experiment by monitoring one of the fluorescence lines.
Flexible Drug Delivery Chip, its Fabrication Method and Uses Thereof
(2011-04-28)
Chen San-Yuan
;
Huang Wei-Chen
;
Liu Dean-Mo
Nanodevice and method for in vivo monitoring and release of drugs are provided. The disclosed nanodevice is characterized in having a drug-loaded nanosphere that is capable of releasing the encapsulated drugs upon magnetically stimulation. The nanodevice may also be used as a contrast agent for in vivo imaging and monitoring the concentration and distribution of the released drugs and/or active compounds injected separately into a target site of a subject.
Computational Study on the Reactions of H(2)O(2) on TiO(2) Anatase (101) and Rutile (110) Surfaces
(2011-04-30)
Huang, Wen-Fei
;
Raghunath, P.
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
This study investigates the adsorption and reactions of H(2)O(2) on TiO(2) anatase (101) and rutile (110) surfaces by first-principles calculations based on the density functional theory in conjunction with the projected augmented wave approach, using PW91, PBE, and revPBE functionals. Adsorption mechanisms of H(2)O(2) and its fragments on both surfaces are analyzed. It is found that H(2)O(2), H(2)O, and HO preferentially adsorb at the Ti(5c) site, meanwhile HOO, O, and H preferentially adsorb at the (O(2c))(Ti(5c)), (Ti(5c))(2), and O(2c) sites, respectively. Potential energy profiles of the adsorption processes on both surfaces have been constructed using the nudged elastic band method. The two restructured surfaces, the 1/3 ML oxygen covered TiO(2) and the hydroxylated TiO(2), are produced with the H(2)O(2) dehydration and deoxidation, respectively. The formation of main products, H(2)O(g) and the 1/3 ML oxygen covered TiO(2) surface, is exothermic by 2.8 and 5.0 kcal/mol, requiring energy barriers of 0.8 and 1.1 kcal/mol on the rutile (110) and anatase (101) surface, respectively. The rate constants for the H(2)O(2) dehydration processes have been predicted to be 6.65 x 10(-27) T(4.38) exp(-0.14 kcal mol(-1)/RT) and 3.18 x 10(-23) T(5.60) exp(-2.92 kcal mol(-1)/RT) respectively, in units of cm(3) molecule(-1) s(-1). (C) 2010 Wiley Periodicals, Inc. J Comput Chem 32: 1065-1081, 2011
Computational Study on the Reactions of H2O2 on TiO2 Anatase (101) and Rutile (110) Surfaces
(2011-04-30)
Huang, Wen-Fei
;
Raghunath, P.
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
This study investigates the adsorption and reactions of H2O2 on TiO2 anatase (101) and rutile (110) surfaces by first-principles calculations based on the density functional theory in conjunction with the projected augmented wave approach, using PW91, PBE, and revPBE functionals. Adsorption mechanisms of H2O2 and its fragments on both surfaces are analyzed. It is found that H2O2, H2O, and HO preferentially adsorb at the Ti-5c site, meanwhile HOO, O, and H preferentially adsorb at the (O-2c)(Ti-5c), (Ti-5c)(2), and O-2c sites, respectively. Potential energy profiles of the adsorption processes on both surfaces have been constructed using the nudged elastic band method. The two restructured surfaces, the 1/3 ML oxygen covered TiO2 and the hydroxylated TiO2, are produced with the H2O2 dehydration and deoxidation, respectively. The formation of main products, H2O(g) and the 1/3 ML oxygen covered TiO2 surface, is exothermic by 2.8 and 5.0 kcal/mol, requiring energy barriers of 0.8 and 1.1 kcal/mol on the rutile (110) and anatase (101) surface, respectively. The rate constants for the H2O2 dehydration processes have been predicted to be 6.65 x 10(-27) T-4.38 exp(-0.14 kcal mol(-1)/RT) and 3.18 x 10(-23) T-5.60 exp(-2.92 kcal mol(-1)/RT) respectively, in units of cm(3) molecule(-1) s(-1). (C) 2010 Wiley Periodicals, Inc. J Comput Chem 32: 1065-1081, 2011
A Delegation Framework for Task-Role Based Access Control in WFMS
(2011-05-01)
Hsu, Hwai-Jung
;
Wang, Feng-Jian
;
資訊工程學系
;
Department of Computer Science
Access control is important for protecting information integrity in workflow management system (WfMS). Compared to conventional access control technology such as discretionary, mandatory, and role-based access control models, task-role-based access control (TRBAC) model, an access control model based on both tasks and roles, meets more requirements for modern enterprise environments. However, few discussions on delegation mechanisms for TRBAC are made. In this paper, a framework considering temporal constraints to improve delegation and help automatic delegation in TRBAC is presented. In the framework, the methodology for delegations requested from both users and WfMS is discussed. The constraints for delegatee selection such as delegation loop and separation of duty (SOD) are addressed. With the framework, a sequence of algorithms for delegation and revocation of tasks are constructed gradually. Finally, a comparison is made between our approach and the representative related works.
Microstructures and electrical properties of lead-based PBZNZT and lead-free BNKT piezoelectric ceramics using microwave sintering
(2011-05-01)
Chen, P. Y.
;
Chen, C. S.
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Chou, C. C.
;
Tseng, T. Y.
;
Chen, H. D.
This paper is a comparative study involving sintering conditions (different sintering temperatures and time), process (conventional and microwave sintering), microstructures, and electrical measurements to investigate the mechanism of microwave absorption, and the difference in the microstructural characteristics and electrical properties of lead-based and lead-free ceramics. The lead-based piezoelectric ceramics are x(0.94PbZn(1/3)Nb(2/3)O(3) + 0.06BaTiO(3)) + (1 - x) PbZr(y)Ti(1) (y)O(3) where x = 0.5, y = 0.52 (abbreviated as PBZNZT) and the lead-free ceramics are (Bi(0.5)(Na(1-x)K(x))(0.5))TiO(3) where x = 0.18 (abbreviated as BNKT), all sintered by microwave heating. Experimental results indicate that PBZNZT and BNKT specimens have different microwave absorption efficiencies. Compared with BNKT samples, PBZNZT samples absorb microwave radiation more efficiently in MWS process. This might be attributed to the contribution of the dielectric constant and dipole loss which might dominate the absorption of microwave energy for ferroelectric and piezoelectric materials. HRTEM and energy dispersive spectroscopic investigations show that the grain boundaries of MWS samples exhibit less PbO and ZnO segregation than those of CS samples form PBZNZT specimens. On the other hand, BNKT specimens exhibit no compositional segregation at the grain boundaries after the CS and MWS processes. In addition, the MWS process can achieve a more uniform composition and crystallization in PBZNZT and BNKT ceramics, thus improving the electrical properties. (C) 2011 Elsevier B.V. All rights reserved.
Enhanced light harvesting with pi-conjugated cyclic aromatic hydrocarbons for porphyrin-sensitized solar cells
(2011-05-01)
Wang, Chin-Li
;
Chang, Yu-Cheng
;
Lan, Chi-Ming
;
Lo, Chen-Fu
;
Diau, Eric Wei-Guang
Zinc porphyrins in a series bearing a phenylethynyl, naphthalenylethynyl, anthracenylethynyl, phenanthrenylethynyl or pyrenylethynyl substituent, denoted LD1, LD2, LD3a, LD3p or LD4, respectively, were prepared as photosensitizers for dye-sensitized solar cells. The overall efficiencies of the corresponding devices show a trend LD4 > LD3p > LD2 > LD3a > LD1. Significantly, LD4 features J(SC)/mA cm(-2) 19.627, V(OC)/V = 0.711, and FF = 0.721, giving an efficiency eta = 10.06% of power conversion. This value is superior to that of a N719-based solar cell fabricated under similar experimental conditions. The remarkable performance of the LD4 cell is rationalized to be due to the broader and more red-shifted spectral feature that makes the IPCE spectrum to cover broadly across the entire visible region, 400-800 nm.
微波退火提升有機電子元件特性之方法
(2011-05-01)
陳方中
;
葛祖榮
;
林義凱
本發明為一種微波退火提升有機電子元件特性之方法，包括下列步驟：提供有機電子元件；以及微波退火有機電子元件。因為微波退火具有非接觸式、退火標的具選擇性、以及退火時間短等特性，且可以僅針對有機電子元件的有機主動層(Organic active layer)退火，使得有機主動層內的有機分子在短時間內重新排列以提高有機分子的排列程度，進而增加光電轉換效率，並提升有機電子元件的特性。
Design and performance analysis on adaptive reservation-assisted collision resolution protocol for WLANs
(2011-05-01)
Lin, Jia-Shi
;
Feng, Kai-Ten
;
電機工程學系
;
Department of Electrical and Computer Engineering
In conventional IEEE 802.11 medium access control protocol, the distributed coordination function is designed for the wireless stations (WSs) to perform channel contention within the wireless local area networks (WLANs). Packet collision is considered one of the major issues within this type of contention-based scheme, which can severely degrade network performance for the WLANs. Research work has been conducted to modify the random backoff mechanism in order to alleviate the packet collision problem while the WSs are contending for channel access. However, most of the existing work can only provide limited throughput enhancement under specific number of WSs within the network. In this paper, an adaptive reservation-assisted collision resolution (ARCR) protocol is proposed to improve packet collision resulting from the random access schemes. With its adaptable reservation period, the contention-based channel access can be adaptively transformed into a reservation-based system if there are pending packets required to be transmitted between the WSs and the access point. Analytical model is derived for the proposed ARCR scheme in order to evaluate and validate its throughput performance. It can be observed from both analytical and simulation results that the proposed protocol outperforms existing schemes with enhanced channel utilization and network throughput.
搜救犬引導員袁明桂
(2011-05-01)
黃萱如
;
Department of Communication and Technology
;
傳播與科技學系
轉個彎進到馴養中心後面的房舍，一聲聲響亮的狗吠此起彼落，大約五、六隻德國狼犬從鐵欄杆裡探出頭，朝闖入者發出警告。「安靜！」威嚴的喝斥聲來自一個身穿著深藍色的工作制服的人，他手持著水管沖洗著狗舍，且毫不在意被沾濕的褲腳，他，是袁明桂，一位搜救犬的資深引導員。
用於磁振造影之磁性奈米粒子
(2011-05-01)
王雲銘
;
陳亭蓉
本發明提供一種用於磁振造影之磁性奈米粒子，包含一個具有一表面且由超順磁性氧化鐵奈米粒子所構成之核，及多數個與核之表面共價偶合且由下式(I)所示之矽氧烷基團：式(I)之各個取代基及n、m及p的意義如說明書及申請專利範圍所界定。本發明之磁性奈米粒子可用作為磁振造影對比劑。
Analytical Solutions of Multilevel Space-Vector PWM for Multiphase Voltage Source Inverters
(2011-05-01)
Hu, Jwu-Sheng
;
Chen, Keng-Yuan
;
Shen, Te-Yang
;
Tang, Chi-Him
;
電機工程學系
This study systematically analyzes multilevel space-vector pulse width modulation for a multiphase voltage source inverter (VSI). The instantaneous output voltages of the VSI, which are called space vectors, can be classified according to the switching states of the VSI. By applying the eigenspace decomposition of the system matrix, the n-phase VSI control problem can be solved analytically. This analysis leads to a switching strategy that uses the fewest space vectors and minimum total conduction time. This yields a minimum switching number and efficient dc supply utilization. Further, the switching strategy of a multilevel multiphase VSI system can be solved based on the switching strategy of a two-level multiphase VSI. Simulations and experimental results confirm the effectiveness of the proposed algorithm.
Radiative recombination of indirect exciton in type-II ZnSeTe/ZnSe multiple quantum wells
(2011-05-01)
Chia, Chin-Hau
;
Fan, Wen-Chung
;
Lin, Yen-Chen
;
Chou, Wu-Ching
;
電子物理學系
The tunability of the emission energy, oscillator strength and photoluminescence (PL) efficiency by varying the well thickness and excitation density was demonstrated in the ZnSe(0.8)Te(0.2)/ZnSe multiple quantum wells. A significant blueshift about 260 meV of the PL peak energy was observed as the well width decreased from 5 to 1 nm. An extraordinary long lifetime (300 ns) of the recombination for the widest sample was detected. The binding energy of the indirect excitons is determined as 12 meV for the thinnest sample. The reduction of PL efficiency by thermal energy is greatly suppressed by employing a high excitation power. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
光電裝置
(2011-05-01)
范士岡
;
邱誠樸
本發明提供一種光電裝置，包含一流體、一導體，及一設置在該導體與該流體之間並與該導體及該流體連接的介電層，使得該介電層的一區域是受該流體所覆蓋，該介電層包含一基體及限制於該基體內之液晶；藉此，當對該光電裝置施加一電壓時，該流體及該導體之間形成一電場並通過該介電層之該區域，使得該流體的狀態及位於該介電層之該區域內之液晶的指向同時被改變。本發明之光電裝置可有效控制流體之狀態以及可發揮電光效應。
Efficient Tool Replacement Procedure Based on Yield Evaluation
(2011-05-01)
Lin, Chen-ju
;
Pearn, W. L.
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Tool wear is an inevitable problem in many machining processes. The problem constitutes an inseparable component of variation and can be considered as a systematic assignable cause of process variability. Tool replacement should be initiated when the yield drops below a certain level. Determining the best time for tool replacement is essential to balance between production quality and tool utilization. The yield index, S(pk), has been effectively applied to assess the yield of processes. However, its ordinary measure is inaccurate when data is contaminated by inseparable nonrandom variation. Yield evaluation becomes imprecise when a process is subjected to the tool wear problem. Thus, this paper presents an efficient procedure that determines the best time to replace tools under an extremely low fraction of defectives. The variation from assignable causes is removed by using the linear regression technique. A modified estimator of the S(pk) index with its distribution is proposed to evaluate the processes with the tool wear problem.
An inverted method for culturing dissociated mouse hippocampal neurons
(2011-05-01)
Chen, Wen-Shin
;
Yueh, Chao-Yen
;
Huang, Yung-An
;
Hwang, Eric
;
生物科技學系
Dissociated hippocampal neuron culture has long been the model system of choice for many neuroscientists. The ability to culture dissociated hippocampal neurons from genetically modified mice provides an invaluable tool for studying many neuronal processes. In this study, we established a novel method to culture dissociated hippocampal neurons from embryonic and neonatal mice. Dissociated neurons were cultured in a microchamber between the glass coverslip and the plastic cell container without the use of glial feeder cells. Our method significantly simplifies the preparation while produces healthy and long-lived neuronal cultures that are difficult to achieve without the use of feeder cells. (C) 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.