Browsing by Issue Date, starting with "2014-12-15"

Now showing 1 - 20 of 24599

Growth orientations of semipolar ZnO on GaN(1 1 (2)over-bar 2)
(2014-12-15)
Shih, Yi-Sen
;
Lin, Pei-Yin
;
Chen, Jr-Yu
;
Chang, Li
;
材料科學與工程學系
On semipolar GaN(1 1 (2) over bar 2), epitaxial ZnO grown by chemical vapor deposition can form in two different semipolar orientations as evidenced by transmission electron microscopy and X-ray diffraction. One orientation relationship is shown to be ZnO(1 1 (2) over bar 2)//GaN(1 1 (2) over bar 2) and [(1) over bar 1 0 0](ZnO)//[(1) over bar 1 0 0](GaN) which is expected for ZnO growth on GaN(1 1 (2) over bar 2), while the other is a newly found relationship of ZnO((1) over bar 0 1 (1) over bar)//GaN(0 0 0 2) and [5 (7) over bar 2 (3) over bar](ZnO)//[(1) over bar 1 0 0](GaN). (C) 2014 Elsevier B.V. All rights reserved.
Eigenvalue solvers for three dimensional photonic crystals with face-centered cubic lattice
(2014-12-15)
Huang, Tsung-Ming
;
Hsieh, Han-En
;
Lin, Wen-Wei
;
Wang, Weichung
;
應用數學系
To numerically determine the band structure of three-dimensional photonic crystals with face-centered cubic lattices, we study how the associated large-scale generalized eigenvalue problem (GEP) can be solved efficiently. The main computational challenge is due to the complexity of the coefficient matrix and the fact that the desired eigenvalues are interior. For solving the GEP by the shift-and-invert Lanczos method, we propose a preconditioning for the associated linear system therein. Recently, a way to reformat the GEP to the null space free eigenvalue problem (NFEP) is proposed. For solving the NFEP, we analyze potential advantages and disadvantages of the null space free inverse Lanczos method, the shift-invert residual Arnoldi method, and the Jacobi-Davidson method from theoretical viewpoints. These four approaches are compared numerically to find out their properties. The numerical results suggest that the shift-invert residual Arnoldi method with an initialization scheme is the fastest and the most robust eigensolver for the target eigenvalue problems. Our findings promise to play an essential role in simulating photonic crystals. (C) 2014 Elsevier B.V. All rights reserved.
Eigenvalue solvers for three dimensional photonic crystals with face-centered cubic lattice
(2014-12-15)
Huang, Tsung-Ming
;
Hsieh, Han-En
;
Lin, Wen-Wei
;
Wang, Weichung
;
應用數學系
To numerically determine the band structure of three-dimensional photonic crystals with face-centered cubic lattices, we study how the associated large-scale generalized eigenvalue problem (GEP) can be solved efficiently. The main computational challenge is due to the complexity of the coefficient matrix and the fact that the desired eigenvalues are interior. For solving the GEP by the shift-and-invert Lanczos method, we propose a preconditioning for the associated linear system therein. Recently, a way to reformat the GEP to the null space free eigenvalue problem (NFEP) is proposed. For solving the NFEP, we analyze potential advantages and disadvantages of the null space free inverse Lanczos method, the shift-invert residual Arnoldi method, and the Jacobi-Davidson method from theoretical viewpoints. These four approaches are compared numerically to find out their properties. The numerical results suggest that the shift-invert residual Arnoldi method with an initialization scheme is the fastest and the most robust eigensolver for the target eigenvalue problems. Our findings promise to play an essential role in simulating photonic crystals. (C) 2014 Elsevier B.V. All rights reserved.
Influence of methyl red as a dopant on the electrical properties and device performance of liquid crystals
(2014-12-15)
Wu, Po-Chang
;
Hou, Chien-Tsung
;
Hsiao, Yu-Cheng
;
Lee, Wei
;
影像與生醫光電研究所
The ionic effect in nematic liquid-crystal (LC) cells containing the azo dye methyl red was investigated by means of dielectric spectroscopy, measurements of voltage holding ratio (VHR) and ultraviolet/visible absorption spectroscopy. The experimental results indicated that incorporating a minute amount of the methyl red (< 0.03 wt%) in the LC host leads to the suppression of the ionic effect caused by impurity ions. Practically, the doped LC cells with a dye content of 0.02 wt% showed improved VHR and promoted lifetime by 15% and 180%, respectively, in virtually no expense of the optical transmittance. (C)2014 Optical Society of America
Color-filter-free spatial visible light communication using RGB-LED and mobile-phone camera
(2014-12-15)
Chen, Shih-Hao
;
Chow, Chi-Wai
;
光電工程學系
;
光電工程研究所
;
Department of Photonics
A novel color-filter-free visible-light communication (VLC) system using red-green-blue (RGB) light emitting diode (LED) and mobile-phone camera is proposed and demonstrated for the first time. A feature matching method, which is based on the scale-invariant feature transform (SIFT) algorithm for the received grayscale image is used instead of the chromatic information decoding method. The proposed method is simple and saves the computation complexity. The signal processing is based on the grayscale image computation; hence neither color-filter nor chromatic channel information is required. A proof-of-concept experiment is performed and high performance channel recognition is achieved. (C) 2014 Optical Society of America
Fast phase transformation due to electromigration of 18 mu m microbumps in three-dimensional integrated-circuit integration
(2014-12-15)
Chang, Y. W.
;
Chen, Chih
;
Chang, T. C.
;
Zhan, C. J.
;
Juang, J. Y.
The electromigration behavior was investigated in 18-mu m SnAg microbumps at 150 degrees C. The monitored resistance increase abruptly soon after the current stressing of 4.6 x 10(4) A/cm(2) was applied but the resistance rose much slower after a certain period of time. The formation of the high-resistivity Ni3Sn4 intermetallic compounds (IMCs) was responsible for the abrupt resistance increase in the beginning of the current stressing. The whole solder joint was transformed into an IMC joint. Because IMC has a higher electromigration resistance than the solder, a much slower increase in resistance was resulted after the solder joint was transformed into IMCs. (C) 2014 Elsevier B.V. All rights reserved.
Quantum control study of ultrafast optical responses in semiconductor quantum dot devices
(2014-12-15)
Huang, Jung Y.
;
Lin, Chien Y.
;
Liu, Wei-Sheng
;
Chyi, Jen-Inn
;
光電工程學系
Two quantum control spectroscopic techniques were applied to study InAs quantum dot (QD) devices, which contain different strain-reducing layers. By adaptively control light matter interaction, a delayed resonant response from the InAs QDs was found to be encoded into the optimal phase profile of ultrafast optical pulse used. We verified the delayed resonant response to originate from excitons coupled to acoustic phonons of InAs QDs with two-dimensional coherent spectroscopy. Our study yields valuable dynamical information that can deepen our understanding of the coherent coupling process of exciton in the quantum-confined systems. (C) 2014 Optical Society of America
A panel data parametric frontier technique for measuring total-factor energy efficiency: An application to Japanese regions
(2014-12-15)
Honma, Satoshi
;
Hu, Jin-Li
;
經營管理研究所
;
Institute of Business and Management
Using the stochastic frontier analysis model, we estimate TFEE (total-factor energy efficiency) scores for 47 regions across Japan during the years 1996-2008. We extend the cross-sectional stochastic frontier model proposed by Zhou et al. (2012) to panel data models and add environmental variables. The results provide not only the TFEE scores, in which statistical noise is taken into account, but also the determinants of inefficiency. The three stochastic TFEE scores are compared with a TFEE score derived using data envelopment analysis. The four TFEE scores are highly correlated with one another. For the inefficiency estimates, higher manufacturing industry shares and wholesale and retail trade shares correspond to lower TFEE scores. (C) 2014 Elsevier Ltd. All rights reserved.
Wired and wireless convergent extended-reach optical access network using direct-detection of all-optical OFDM super-channel signal
(2014-12-15)
Chow, C. W.
;
Yeh, C. H.
;
Sung, J. Y.
;
Hsu, C. W.
;
光電工程學系
We propose and demonstrate the feasibility of using all-optical orthogonal frequency division multiplexing (AO-OFDM) for the convergent optical wired and wireless access networks. AO-OFDM relies on all-optically generated orthogonal subcarriers; hence, high data rate (> 100 Gb/s) can be easily achieved without hitting the speed limit of electronic digital-to-analog and analog-to-digital converters (DAC/ADC). A proof-of-concept convergent access network using AO-OFDM super-channel (SC) is demonstrated supporting 40 - 100 Gb/s wired and gigabit/s 100 GHz millimeter-wave (MMW) ROF transmissions. (C) 2014 Optical Society of America
Anti-corrosion characteristics of polyimide/h-boron nitride composite films with different polymer configurations
(2014-12-15)
Huang, Yi-Chia
;
Lo, Teng-Yuan
;
Chao, Cheun-Guang
;
Whang, Wha-Tzong
;
材料科學與工程學系
Anti-corrosive polyimide/hexagonal boron nitride (PI/h-EN) composite films were prepared with different monomers to offer different polymer configurations: rigid and soft. In PI/h-BN composite films, different configurations of polymers show different crystallinity trends of the polymer matrix. In our study, the degree of crystallinity in rigid polymer decreases with the EN content; in flexible polymers it is independent of the BN content. It is worth noting that BN in different PI matrices can effectively enhance the protection of steel from corrosion. With a flexible PI matrix, the PI/h-BN coating exhibited better resistance to water vapor and better anti-corrosion. Only 5 wt.% of h-BN in the composite is enough to offer high anti-corrosion, a positive corrosion voltage. (C) 2014 Elsevier B.V. All rights reserved.
GaN-Based Resonant-Cavity LEDs Featuring a Si-Diffusion-Defined Current Blocking Layer
(2014-12-15)
Yeh, Pinghui Sophia
;
Yu, Meng-Chun
;
Lin, Jia-Huan
;
Huang, Ching-Chin
;
Liao, Yen-Chao
GaN-based resonant-cavity light-emitting diode (RCLED) featuring a Si-diffusion-defined confinement structure is reported for the first time. The charge-coupled device images exhibited round, bright spots of sizes corresponding to the diffusion-defined aperture sizes under continuous-wave high-current-density operation and at room temperature. The full widths at half maximum of the electroluminescence spectra were 2 and 1.5 nm for 10-and 5-mu m-diameter RCLEDs, respectively. A stable peak wavelength of 406.6 nm was maintained at various injection currents. The results suggest Si diffusion is an effective means to reduce aperture size. The design and fabrication of the devices are described.
具紫外光吸收層之薄膜電晶體
(2014-12-16)
謝漢萍
;
劉柏村
;
蔡韻竹
;
蔡旻諺
;
鄧立峯
一種薄膜電晶體，其包括透明基板、閘極設置於透明基板上、閘極絕緣層設置於閘極及透明基板上、半導體主動層設置於閘絕緣層上、電極層與半導體層藉由電力接觸且曝露出部份的半導體主動層以及紫外光吸收層設置於半導體主動層上，藉由紫外光吸收層在可見光的範圍之光穿透率及其具備保護元件不受外界水氣氧化而影響光電特性之優點，並且藉由薄膜沉積的過程中調整參數來改變其導電度，可降低照光後元件轉移特性曲線變動的光敏感度，並且可穩定啟始電壓使其在一定的範圍內進行操作。
針對使用者裝置在異質無線網路中維持服務連續性傳輸之系統結構及其傳輸方法
(2014-12-16)
曾建超
;
詹珉誠
本發明提供一種針對使用者裝置在異質無線網路中維持服務連續性傳輸之系統結構及其傳輸方法,包括一應用程式介面、一換手決策模組及一會談連續模組,當網路環境改變或應用程式介面變更排程之優先順序時,利用換手決策模組重新選擇基地台,使用者裝置會在重新選擇基地台後取得新的網路位址(IP),再利用會談連續模組將要對應裝置收到的所有封包進行整合排序。因此藉由換手決策模組預先做好換手準備,及會談連續模組將換手前後或使用者裝置透過複數路徑傳送至一對應裝置之封包排序整合,達到連續性及多路徑傳輸之目的。
互動式提醒方法與系統
(2014-12-16)
吳炳飛
;
陳盈翰
;
王承濬
本發明為一種互動式提醒方法，包括：一第一使用者將目前該第一使用者的位置與一目的地輸入一第一行動裝置，以讓該第一行動裝置進行一路徑規劃，進而產生一預定導航路徑資訊，並將該預定導航路徑資訊與目前該第一使用者的位置上傳至一遠端伺服器；以及一第二使用者應用一第二行動裝置查看該遠端伺服器所儲存的該預定路徑資訊與目前該第一使用者的位置，進而應用一指定方式，以讓該第一使用者到達該目的地時，該遠端伺服器會產生一提示信號，提醒該第二使用者。
分波多工光纖網路系統
(2014-12-16)
宋峻宇
;
鄒志偉
;
葉建宏
本發明提供一種分波多工光纖網路系統,其係包括一訊號提供端產生至少一組複數不同波長的波長信號,訊號提供端並訊號連接複數調變模組,每一調變模組並分別連接用戶接收端,調變模組包括:一控制單元產生一亂數序列碼,並根據亂數序列碼對應產生一控制訊號至第一調變單元,其並訊號連接訊號提供端,以接收波長信號,再根據控制訊號,控制第一調變單元擷取一波長信號,並可根據亂數序列碼快速變換控制訊號,使第一調變單元快速變換擷取不同波長的波長信號至用戶接收端,以防止攻擊者攻擊固定波長。
Characterization and density control of GaN nanodots on Si (111) by droplet epitaxy using plasma-assisted molecular beam epitaxy
(2014-12-17)
Yu, Ing-Song
;
Chang, Chun-Pu
;
Yang, Chung-Pei
;
Lin, Chun-Ting
;
Ma, Yuan-Ron
In this report, self-organized GaN nanodots have been grown on Si (111) by droplet epitaxy method, and their density can be controlled from 1.1 x 10(10) to 1.1 x 10(11) cm(-2) by various growth parameters, such as substrate temperatures for Ga droplet formation, the pre-nitridation treatment of Si substrate, the nitridation duration for GaN crystallization, and in situ annealing after GaN formation. Based on the characterization of in situ RHEED, we can observe the surface condition of Si and the formation of GaN nanodots on Si. The surface nitridaiton treatment at 600 degrees C provides a-SiNx layer which makes higher density of GaN nanodots. Crystal GaN nanodots can be observed by the HRTEM. The surface composition of GaN nanodots can be analyzed by SPEM and mu-XPS with a synchrotron x-ray source. We can find GaN nanodots form by droplet epitaxy and then in situ annealing make higher-degree nitridation of GaN nanodots.
WAVELENGTH-DIVISION MULTIPLEXING (WDM) OPTICAL FIBER NETWORK SYSTEM
(2014-12-18)
SUNG JIUN-YU
;
CHOW CHI-WAI
;
YEH CHIEN-HUNG
A wavelength-division multiplexing (WDM) optical fiber network system is disclosed, which comprises a signal provider generating at least one set of wavelength signals of a plurality of different wavelengths and coupled to a plurality of modulation modules. The modulation modules respectively coupled to a user receiver. The modulation module comprises a control unit generating a random sequence and a control signal corresponding to the random sequence, and transmitting the control signal to a first modulation unit. The control unit is coupled to the signal provider to receive the wavelength signals and controls the first modulation to retrieve a wavelength signal according to the control signal. The control unit rapidly changes the control signal according to the random sequence whereby the first modulation unit rapidly retrieves the wavelength signals of different wavelengths and transmits them to the user receiver, so as to prevent a specific wavelength from attack.
Incidence rates of tuberculosis in chronic hepatitis C infected patients with or without interferon based therapy: a population-based cohort study in Taiwan
(2014-12-19)
Lin, Shang-Yi
;
Chen, Tun-Chieh
;
Lu, Po-Liang
;
Lin, Chun-Yu
;
Lin, Wei-Ru
Background: It is debated whether interferon-based therapy (IBT) would affect the incidence of active tuberculosis (TB) among hepatitis C virus (HCV) infected patients. Although some case reports have demonstrated a possible association, the results are currently inconclusive. Therefore, we conducted a nation-wide population study to investigate the incidence of active TB in HCV infected patients receiving IBT in Taiwan. Methods: This 9-year cohort study was based on the Longitudinal Health Insurance Database 2000 (LHID 2000) consisting of 1,000,000 beneficiaries randomly selected from all Taiwan National Health Insurance enrollees in 2000 (>23.7 million). This insurance program covers all citizens in Taiwan. We conducted a retrospective cohort study that identified subjects with HCV infection. IBTs were defined as regimens that included interferon alpha, peginterferon alpha 2a and peginterferon alpha 2b for at least 2 months. Among them, 621 subjects received IBT, and 2,460 age-and gender-matched subjects were enrolled for analysis. The Cox proportional hazards models were used to estimate the hazard ratio (HR) for active TB, and associated confidence intervals (CIs), comparing IBT cohort and untreated cohort. The endpoint in this study was whether an enrolled subject had a new diagnosis of active TB. Results: During the 9-year enrollment period, the treated and untreated cohorts were followed for a mean (+/- SD) duration of 6.97 +/- 0.02 years and 8.21 +/- 0.01 years, respectively. The cumulative incidence rate of active TB during this study period was 0.150 and 0.151 per 100 person-years in the IBT treated and untreated cohorts, respectively. There was no significant difference in the incidence of active TB in either cohort during a 1-year follow-up (Adjusted Hazard Ratio (AHR): 2.81, 95% Confidence Interval (95% CI): 0.61 - 12.98) or the long-term follow-up (AHR: 1.02, 95% CI: 0.28 - 3.78). The Cox proportional hazards model demonstrated that IBT was not a risk factor for active TB. The only risk factor for active TB was the occurrence of hepatic encephalopathy. Conclusion: Our results showed that IBT is associated with increased hazard of active TB in HCV infected patients in 1-year follow-up; however, the effect sizes were not statistically significant.
Study on Anharmonic Effect of the Unimolecular Reaction of CH2(D-2)FO
(2014-12-20)
Zhong, Jingjun
;
Li, Qian
;
Luo, Ji
;
Xia, Wenwen
;
Yao, Li
Study on the unimolecular reaction for CH2FO and CD2FO is carried out. The structures, energy barriers and zero point energy of the three channels in the title unimolecular reactions are computed with the MP2/6-311++G(3df, 3pd) method. RRKM theory is used to calculate the rate constants of canonical case at temperature range of 500-5000 K and microcanonical system at total energy of 19.05-71.68 kcal/mol. The results indicate that the anharmonic effect and isotope effect are very small for the three channels, and the anharmonic rate constants, around 10(9)-10(11) s(-1), are close to the experimental prediction reasonably.
Wide-converter lens design for a pico projector
(2014-12-20)
Pan, Jui-Wen
;
Chen, Yi-Chin
;
光電系統研究所
;
照明與能源光電研究所
;
生醫電子轉譯研究中心
In this paper, we propose a concept for the design of a 0.702x wide-converter lens for a 0.3 in. digital micromirror device. This 0.702x wide-converter lens is capable of enlarging the size of the original projected image at the same projection distance. This 0.702x wide-converter lens is attached in front of the projection lens of a pico projector (PP). Compared with the projection lens of a PP without the 0.702x wide-converter lens, there is an increase in the size of the original projected image of 42.4% at the same projection distance. In other words, there is a saving of projection distance of 29.78% to obtain a projected image of the same size. (C) 2014 Optical Society of America