Browsing by Issue Date, starting with "2011-03-31"

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Mechanistic Aspect of Surface Modification on Glass Substrates Assisted by Single Shot Pulsed Laser-Induced Fragmentation of Gold Nanoparticles
(2011-03-31)
Hashimoto, Shuichi
;
Uwada, Takayuki
;
Hagiri, Masahide
;
Shiraishi, Ryowya
;
應用化學系
This paper describes the mechanistic investigation on the photomodification of a borosilicate glass substrate assembled with 47 +/- 8 nm gold nanoparticles and exposed to a single shot of 532 nm nanosecond pulsed-laser light. The laser fluences ranging from 180 to 430 mJ cm(-2) pulse(-1), the values of which are 2 orders of magnitude lower than the breakdown threshold of quartz of 15-20 J cm(-2) pulse(-1) were used. Upon photomodification, the craters of similar to 20 nm diameter and similar to 10 tun depth were formed on the glass surface simultaneously with the laser-induced splitting of Au nanopartides to generate smaller particles of 15 nm diameter. The number density of the craters increased depending on the laser fluence with a sharp rise, the onset of which occurred at similar to 160-170 mJ cm(-2) pulse(-1), and reached a value of twice the number density of original Au particles (150 +/- 10 particles mu m(-2)) with a weak tendency to level off at high fluences. The onset of the crater formation coincides with splitting of gold nanopartides due to the temperature rise above the boiling point of gold resulting from the absorption of the laser energy. Thus, the explosive evaporation of gold nanoparticles is postulated to play a crucial role for the modification observed here. This assumption gained a solid support from the estimation of laser fluence-dependent thermoacoustic pressures due to the sudden evaporation of gold. This finding may represent a new application of the laser ablation/fragmentation of nanoparticles to material processing.
Influence of hydrogen plasma treatment on charge storage characteristics in high density tungsten nanocrystal nonvolatile memory
(2011-03-31)
Chen, Shih-Cheng
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Chang, Ting-Chang
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Chen, Wei-Ren
;
Lo, Yuan-Chun
;
Wu, Kai-Ting
This study focuses on the influence of a hydrogen plasma treatment on electrical properties of tungsten nanocrystal nonvolatile memory. The X-ray photon emission spectra show that, after the hydrogen plasma treatment, a change in binding energy occurs such that Si(x+) and Si(y+) peaks appear at a position that is shifted about 2.3 and 3.3 eV from Si(o+) in Si 2p spectra. This indicates that Si dangling bonds are passivated to form a Si-H bond structure in the SiO(2). Furthermore, the transmission electron microscopy shows cross-sectional and plane-view for the nanocrystal microstructure after the hydrogen plasma treatment. Electrical measurement analyses show improved data retention because the hydrogen plasma treatment enhances the quality of the oxide surrounding the nanocrystals. The endurance and retention properties of the memory device are improved by about 36% and 30%, respectively. (C) 2011 Elsevier By. All rights reserved.
Geometry of classical periodic orbits and quantum coherent states in coupled oscillators with SU(2) transformations
(2011-03-31)
Chen, Y. F.
;
電子物理學系
;
Department of Electrophysics
The geometry of classical dynamics in coupled oscillators with SU(2) transformations is explored and found to be relevant to a family of continuous-transformation orbits between Lissajous and trochoidal curves. The quantum wave-packet coherent states are derived analytically to correspond exactly to the transformation geometry of classical dynamics. By using the quantum wave-packet coherent states derived herein, stationary coherent states are constructed and are shown to possess spatial patterns identical to the transformation geometry between Lissajous and trochoidal orbits.
BIOSENSOR AND ELECTRODE STRUCTURE THEREOF
(2011-03-31)
Liao, Lun-De
;
Chen, Yu-Han
;
Chao, Paul C.-P.
;
Lin, Chin-Teng
;
Sun, Arch
An electrode structure of a biosensor includes a flexible conductive substrate and a plurality of conductive probes protruding from the conductive substrate and configured for contacting a subject and receiving a physiological electric wave signal therefrom. The present invention improves disadvantages of wet electrodes and microstructure electrodes and provides more stable signals that may less decay with time so as to achieve real-time and long-acting measurement for physiological electric wave signal. A biosensor using the electrode structure is also disclosed.
Massive superstring scatterings in the Regge regime
(2011-03-31)
He, Song
;
Lee, Jen-Chi
;
Takahashi, Keijiro
;
Yang, Yi
;
電子物理學系
We calculate four classes of high-energy massive string scattering amplitudes of fermionic string theory at arbitrary mass levels in the Regge regime (RR). We show that all four leading order amplitudes in the RR can be expressed in terms of the Kummer function of the second kind. Based on the summation algorithm of a set of extended signed Stirling number identities, we show that all four ratios calculated previously by the method of decoupling of zero-norm states among scattering amplitudes in the Gross regime can be extracted from this Kummer function in the RR. Finally, we conjecture and give evidence that the existence of these four Gross regime ratios in the RR persists to subleading orders in the Regge expansion of all high-energy fermionic string scattering amplitudes.
資本支出宣告與產業資訊移轉：由知識資本與價值鏈之影響論析
(2011-04-01)
王曉雯
;
李書行
;
吳明政
;
Hsiao-Wen Wang
;
Shu-Hsing Li
企業發生重大事件，或者是宣告相關營運訊息，此項資訊不但會影響公司股價表現，通常亦會影響產業內其它競爭對手的股價報酬。本文以台灣資訊電子業爲樣本，探討高科技公司揭露資本支出產生的資訊內涵與資訊移轉效果是否將會受到宣告公司的知識資本與產業價值鏈階段所影響。實證結果可歸納如下：(1)企業資本支出宣告具有資訊內涵；資本市場將自願性資本支出宣告解讀爲公司向投資人傳遞有利前景之財務報表補充訊息。(2)相較於擁有低知識資本品質企業，投資人對於高知識資本品質公司宣告資本支出，平均而言，將會給予較大股價反應。(3)相較於處在產業價值鏈中；下游企業，投資人對於價值鏈上游公司宣告資本支出，平均而言，將會給予較大股價反應。(4)相較於高知識資本品質（產業價值鏈上游）企業，隨著資本支出宣告窗期逐漸拉長，低知識資本品質（產業價值鏈中；下游）公司宣告資本支出對同產業競爭公司股價異常報酬將會由蔓延效果轉變成爲競爭效果。
Tunable Light Emission from GaN-Based Photonic Crystal with Ultraviolet AlN/AlGaN Distributed Bragg Reflector
(2011-04-01)
Chen, Cheng-Chang
;
Chiu, Ching-Hsueh
;
Yang, Yi-Chun
;
Shih, M. H.
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Chen, Jun-Rong
In this paper, the characteristics of GaN-based two-dimensional (2D) photonic crystal bandedge coupling operation with an ultraviolet AlN/AlGaN distributed Bragg reflector (DBR) have been investigated and analyzed. The 25-pair AlN/Al(0.2)GaN(0.8) DBR shows a high reflectivity of 85% at 375nm with the stop-band width of 15nm. A strong light emission was observed from GaN photonic crystals within high reflectivity region of DBR. The emission wavelength can be also manipulated by varying the radius to lattice constant ratio. The photonic crystal bandedge mode was also characterized with three-dimensional plane-wave expansion (PWE) and finite-difference time-domain (FDTD) simulation. (C) 2011 The Japan Society of Applied Physics
Phase-Change Kinetics of Bi-Fe-(N) Layer for High-Speed Write-Once Optical Recording
(2011-04-01)
Huang, Sung-Hsiu
;
Huang, Yu-Jen
;
Mai, Hung-Chuan
;
Hsieh, Tsung-Eong
;
材料科學與工程學系
In this work, we present the phase-change kinetics of Bi-Fe-(N) layers for write-once optical recording. In situ reflectivity measurement indicated that the phase-change temperature (T(x)) of the Bi-Fe-(N) layers is strongly related to the heating rate. The T(x)'s were about 170 degrees C at low heating rates and approached the melting point of the Bi phase (i.e., 271.4 degrees C) at high rate of heating provided by laser heating. For a 100-nm-thick Bi-Fe-(N) layer, Kissinger's analysis showed that the activation energy of phase transition (E(a)) = 1.24 eV, while the analysis of isothermal phase transition in terms of the Johnson-Mehl-Avrami (JMA) theory showed that the average Avrami exponent (m) = 2.2 and the appropriate activation energy (Delta H) = 5.15 eV. With the aid of X-ray diffraction (XRD) analysis, a two-dimensional phase transition behavior in the Bi-Fe-(N) layers initiated by the melting of the Bi-rich phase was confirmed. For optical disk samples with optimized disk structure and write strategy, the signal properties far exceeding the write-once disk test specifications were achieved. Satisfactory signal properties indicated that the Bi-Fe-(N) system is a promising alternative for high-speed write-once recording in the Blu-ray era. (C) 2011 The Japan Society of Applied Physics
以單晶氧化物作為基板成長纖鋅礦結構半導體非極性ｍ面磊晶層之方法
(2011-04-01)
張立
;
何焱騰
本發明係有關於一種以單晶氧化物作為基板成長非極性m面磊晶層之方法,包括:提供一具有鈣鈦礦結構之單晶氧化物;選擇該單晶氧化物之一平面作為一基板;以及在該基板上以氣相沉積法生長一具有纖鋅礦結構半導體之非極性m面磊晶層。本發明亦提供一種以前述方法成長之具有非極性m面之磊晶層。
Linear coherent distributed estimation over unknown channels
(2011-04-01)
Wu, Chien-Hsien
;
Lin, Ching-An
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We study linear distributed estimation with coherent multiple access channel model and MMSE fusion rule. The flat fading channels are assumed unknown at the fusion center and need to be estimated. We adopt a two-phase approach, which first estimates channels and then estimates the source signal, to minimize the MSE of the estimated signal. We study optimal power allocation under a total network power constraint. We consider the optimal power allocation scheme in which training power and data power for each sensor are optimized, and the equal power allocation scheme in which training power is optimized while data power for each sensor is set equal. In both schemes, the problem is formulated as a constrained optimization problem and analytical closed-form solution is obtained. Analytic results reveal that (i) with estimated channels, the MSE approaches to a finite nonzero value as the number of sensors increases: (ii) the optimal training powers are the same in both schemes: (iii) the MSE performance compared with the case when channels are known shows the penalty caused by channel estimation becomes worse as the number of sensors increases. Simulation results verify our findings. (C) 2010 Elsevier B.V. All rights reserved.
A CMOS 6-Bit 16-GS/s Time-Interleaved ADC Using Digital Background Calibration Techniques
(2011-04-01)
Huang, Chun-Cheng
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Wang, Chung-Yi
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Wu, Jieh-Tsorng
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
An 8-channel 6-bit 16-GS/s time-interleaved analog-to-digital converter (TI ADC) was fabricated using a 65 nm CMOS technology. Each analog-to-digital channel is a 6-bit flash ADC. Its comparators are latches without the preamplifiers. The input-referred offsets of the latches are reduced by digital offset calibration. The TI ADC includes a multi-phase clock generator that uses a delay-locked loop to generate 8 sampling clocks from a reference clock of the same frequency. The uniformity of the sampling intervals is ensured by digital timing-skew calibration. Both the offset calibration and the timing-skew calibration run continuously in the background. At 16 GS/s sampling rate, this ADC chip achieves a signal-to-distortion-plus-noise ratio (SNDR) of 30.8 dB. The chip consumes 435 mW from a 1.5 V supply. The ADC active area is 0.93 x 1.58 mm(2).
Polymer Infrared Proximity Sensor Array
(2011-04-01)
Chen, En-Chen
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Shih, Cheng-Yang
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Dai, Ming-Zhi
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Yeh, Han-Cheng
;
Chao, Yu-Chiang
A near-infrared proximity sensor array is achieved by integrating a polymer light-emitting diode and a polymer photodetector (PD). A green emission is converted into deep red peaked at 670 nm by the inorganic phosphor Intematix R670 with quantum efficiency of over 20%. A bandpass filter is used to select a spectral tail of phosphor luminescence with a wavelength above 700 nm. The emissive polymer is green polyfluorene. The infrared PD contains a thick film of a blend of poly(3-hexylthiophene) and (6,6)-phenyl-C61-butyric acid methyl ester up to a thickness of 8 mu m. Position of a moving object at a distance of 10 cm is detected in real time by the array with dynamic images displayed on the computer screen.
The equivalent structure and some optical properties of the periodic-defect photonic crystal
(2011-04-01)
Pei, Ting-Hang
;
Huang, Yang-Tung
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The concept of the effective medium is used to deal with problems of defects in photonic crystals (PhCs) throughout this paper. First, scattering phenomena in PhCs with defects are investigated and can be very well replaced by those in an effective medium with effective defects in interesting frequency region. It is based on the fact that the Bloch wave in the defect-free PhC very approximates to the wave in the effective medium. Then a periodic-defect PhC created by adding periodic defects into the defect-free PhC is proposed. It can be replaced with an effective PhC by utilizing the concept of effective periodic defects embedded into an effective medium. We verify the equivalence between the periodic-defect PhC and the effective PhC by comparing their photonic band structure (PBS) and photonic band gaps (PBGs) as well as transmissions. Next, the effective PhCs instead of the periodic-defect PhCs are used to investigate the variance of the PBGs by applying different periodic defects. The substitution allows us successfully predicting the negative refraction in the periodic-defect PhC through the PBS of the effective PhC. Finally, the field distributions and Fourier coefficients of waveguide modes in the effective PhC and the periodic-defect PhC are equivalent by the supercell method confirmations. (C) 2011 American Institute of Physics. [doi:10.1063/1.3567296]
Thermomigration of Cu-Sn and Ni-Sn intermetallic compounds during electromigration in Pb-free SnAg solder joints
(2011-04-01)
Chen, Hsiao-Yun
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Thermomigration in Pb-free SnAg solder alloys is investigated during accelerated electromigration tests under 9.7 x 10(3) A/cm(2) at 150 degrees C. It is found that Cu-Sn intermetallic compounds (IMCs) migrate toward the cold end on the substrate side and, as a result, voids accumulate in the chip side for the bump with current flowing from the substrate end to the chip end. Theoretical calculations indicate that the thermomigration force is greater than the electromigration force at a thermal gradient above 400 degrees C/cm for this stressing condition. Copper atoms may migrate against current flow and become the dominant diffusion species. On the other hand, Ni-Sn IMCs did not migrate even under a huge thermal gradient of 1400 degrees C/cm. These findings provide more understanding on the thermomigration of metallization materials in flip-chip solder joints.
OPASS: AN ONLINE PORTFOLIO ASSESSMENT AND DIAGNOSIS SCHEME TO SUPPORT WEB-BASED SCIENTIFIC INQUIRY EXPERIMENTS
(2011-04-01)
Su, Jun-Ming
;
Lin, Huan-Yu
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Tseng, Shian-Shyong
;
Lu, Chia-Jung
;
資訊工程學系
Promoting the development of students' scientific inquiry capabilities is a major learning objective in science education. As a result, teachers require effective assessment approaches to evaluate students' scientific inquiry-related performance. Teachers must also be able to offer appropriate supplementary instructions, as needed, to students. Scientific inquiry capabilities should be assessed by evaluating students' scientific inquiry portfolios in actual hands-on experiments. Although virtual laboratory systems can reduce the cost of conducting scientific inquiry experiments, the manual portfolio assessment approach is still difficult and time-consuming for teachers. Therefore, in this paper, in order to provide students with personalized learning guidance concerning not only the conceptual knowledge, but also the high-order, integrative abilities of scientific inquiry, an Online Portfolio Assessment and Diagnosis Scheme, called OPASS, was proposed to assist teachers in automatically assessing and diagnosing students' abilities as they relate to scientific inquiry performance. Personalized diagnostic reports were generated by employing the rule-based inference approach, which diagnosed learning problems and provided corresponding reasons and remedial suggestions based on teacher-defined assessment knowledge of the scientific inquiry experiment. For the evaluation, experimental results showed that the OPASS was helpful and beneficial for both students and teachers.
Preface to the Special Issue on Geodynamic and Climate-Change Processes over Tibet, Xinjiang and Siberia
(2011-04-01)
Hwang, Cheinway
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Chao, Benjamin Fong
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Freymueller, Jeffrey T.
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Shen, Wenbin
;
Shum, C. K.
Growth of Semipolar InN(10(1)over-bar3) on LaAlO3(112) Substrate
(2011-04-01)
Chen, Wei-Chun
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Tian, Jr-Sheng
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Wang, Wei-Lin
;
Ho, Yen-Teng
;
Chang, Li
In this study, we report the growth and characterization of semipolar (10 (1) over bar3) InN films grown on LaAlO3(112) substrate by metalorganic molecular beam epitaxy. InN films were grown at various substrate temperatures in the range of 465-540 degrees C. Structural and optical properties of semipolar InN were investigated by high resolution X-ray diffraction, scanning electron microscopy, and photoluminescence measurements. The results show that semipolar (10 (1) over bar3) InN layers can be grown at 510 degrees C with the full-width at half maximum of the X-ray rocking curve about 1400 arcsec and electron mobility of 494 cm(2)V(-1)s(-1). (C) 2011 The Japan Society of Applied Physics
Virtual Contour Guided Video Object Inpainting Using Posture Mapping and Retrieval
(2011-04-01)
Ling, Chih-Hung
;
Lin, Chia-Wen
;
Su, Chih-Wen
;
Chen, Yong-Sheng
;
Liao, Hong-Yuan Mark
This paper presents a novel framework for object completion in a video. To complete an occluded object, our method first samples a 3-D volume of the video into directional spatio-temporal slices, and performs patch-based image in-painting to complete the partially damaged object trajectories in the 2-D slices. The completed slices are then combined to obtain a sequence of virtual contours of the damaged object. Next, a posture sequence retrieval technique is applied to the virtual contours to retrieve the most similar sequence of object postures in the available non-occluded postures. Key-posture selection and indexing are used to reduce the complexity of posture sequence retrieval. We also propose a synthetic posture generation scheme that enriches the collection of postures so as to reduce the effect of insufficient postures. Our experiment results demonstrate that the proposed method can maintain the spatial consistency and temporal motion continuity of an object simultaneously.
醫療機構服務公平性影響再惠顧意向之研究
(2011-04-01)
丁秋瑤
;
余泰魁
;
蘇純繒
;
Chiu-Yao Ting
;
Tai-Kuei Yu
本研究主要目的在於建立醫療機構服務補救模式，參酌公平理論(equity theory)、服務補救(service recovery)等領域的相關文獻，修訂成爲醫療機構服務補救模式。研究對象爲蒐集民眾對醫療機構服務接觸產生服務失誤(service failure)者，而醫療機構提出相對應服務補救措施，來評估民眾知覺服務補救過程是否獲得公平對待，而後產生再惠顧意向，回收樣本共計498份有效樣本。本研究應用問卷調查方式與結構模式分析，探討民眾對醫療機構的服務補救策略與再惠顧意向間的關係。本研究建立的研究模式均獲得良好的信度、效度，研究結果發現服務補救公平性正向顯著影響服務補救滿意度及口碑宣傳；再惠顧意向受到服務補救滿意度與口碑宣傳正向顯著影響；服務補救滿意度正向顯著影響口碑宣傳。最後根據研究結果提出理論與實務意涵，並建議未來的研究方向。
Incremental mining of closed inter-transaction itemsets over data stream sliding windows
(2011-04-01)
Chiu, Shih-Chuan
;
Li, Hua-Fu
;
Huang, Jiun-Long
;
You, Hsin-Han
;
資訊工程學系
Mining inter-transaction association rules is one of the most interesting issues in data mining research. However, in a data stream environment the previous approaches are unable to find the result of the new-incoming data and the original database without re-computing the whole database. In this paper, we propose an incremental mining algorithm, called DSM-CITI (Data Stream Mining for Closed Inter-Transaction Itemsets), for discovering the set of all frequent inter-transaction itemsets from data streams. In the framework of DSM-CITI, a new in-memory summary data structure, ITP-tree, is developed to maintain frequent inter-transaction itemsets. Moreover, algorithm DSM-CITI is able to construct ITP-tree incrementally and uses the property to avoid unnecessary updates. Experimental studies show that the proposed algorithm is efficient and scalable for mining frequent inter-transaction itemsets over stream sliding windows.