Browsing by Issue Date, starting with "2016-06-27"

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Suppression of photo-bias induced instability for amorphous indium tungsten oxide thin film transistors with bi-layer structure
(2016-06-27)
Liu, Po-Tsun
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Chang, Chih-Hsiang
;
Chang, Chih-Jui
;
光電工程學系
;
Department of Photonics
This study investigates the instability induced by bias temperature illumination stress (NBTIS) for an amorphous indium-tungsten-oxide thin film transistor (a-IWO TFT) with SiO2 backchannel passivation layer (BPL). It is found that this electrical degradation phenomenon can be attributed to the generation of defect states during the BPL process, which deteriorates the photo-bias stability of a-IWO TFTs. A method proposed by adding an oxygen-rich a-IWO thin film upon the a-IWO active channel layer could effectively suppress the plasma damage to channel layer during BPL deposition process. The bi-layer a-IWO TFT structure with an oxygen-rich back channel exhibits superior electrical reliability of device under NBTIS. Published by AIP Publishing.
DDX3 Represses Stemness by Epigenetically Modulating Tumor-suppressive miRNAs in Hepatocellular Carcinoma
(2016-06-27)
Li, Hao-Kang
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Mai, Ru-Tsun
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Huang, Hsien-Da
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Chou, Chih-Hung
;
Chang, Yi-An
Studies indicate that the presence of cancer stem cells (CSCs) is responsible for poor prognosis of hepatocellular carcinoma (HCC) patients. In this study, the functional role of DDX3 in regulation of hepatic CSCs was investigated. Our results demonstrated that reduced DDX3 expression was not only inversely associated with tumor grade, but also predicted poor prognosis of HCC patients. Knockdown of DDX3 in HCC cell line HepG2 induced stemness gene signature followed by occurrence of self-renewal, chemoreisistance, EMT, migration as well as CSC expansion, and most importantly, DDX3 knockdown promotes tumorigenesis. Moreover, we found positive correlations between DDX3 level and expressions of tumor-suppressive miR-200b, miR-200c, miR-122 and miR-145, but not miR-10b and miR-519a, implying their involvement in DDX3 knockdown-induced CSC phenotypes. In addition, DDX3 reduction promoted up-regulation of DNA methyltransferase 3A (DNMT3A), while neither DNMT3B nor DNMT1 expression was affected. Enriched DNMT3A binding along with hypermethylation on promoters of these tumor-suppressive miRNAs reflected their transcriptional repressions in DDX3-knockdown cells. Furthermore, individual restoration of these tumor-suppressive miRNAs represses DDX3 knockdown-induced CSC phenotypes. In conclusion, our study suggested that DDX3 prevents generation of CSCs through epigenetically regulating a subset of tumor-suppressive miRNAs expressions, which strengthens tumor suppressor role of DDX3 in HCC.
Observing Growth of Nanostructured ZnO in Liquid
(2016-06-28)
Hsieh, Ting-Huan
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Chen, Jui-Yuan
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Huang, Chun-Wei
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Wu, Wen-Wei
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材料科學與工程學系
Hydrothermal synthesis is commonly used to produce a large area of ZnO nanowires because of its simple and inexpensive process. However, the mechanism of hydrothermal synthesis remains unknown. In this work, zinc acetate and HMTA dissolved in deionized water as a precursor solution were sealed in a liquid cell for observation by in situ transmission electron microscopy. The growth of ZnO nanowires was classified into two steps. The first step was the nucleation and growth of ZnO nanoparticles. The ZnO nanoparticles grew as a result of either isotropic monomer attachment on the {2 (11) over bar0} and {0 (1) over bar 10} surfaces or coalescence of nanoparticles in the same crystal arrangement. The second step was the anisotropic growth of ZnO nanoparticles into nanowires on the (0001) surface. Because the (0001) surface is Zn-terminated with positive charges that can attract the negatively charged monomers, i.e., [Zn(OH)(4)](2-),the monomers tended to deposit on the (0001) surface, resulting in ZnO nanowires growing along the [0001] direction. Moreover, the growth of ZnO nanowires was identified to be a reaction controlled system. The direct observation of the dynamic process sheds light on the hydrothermal synthesis method.
Maximum likelihood detection for coded combinerless LINC-OFDM systems
(2016-06-29)
Wu, Wen-Rong
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Cheng, Sheng-Lung
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Hsu, Ying-Pei
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電信工程研究所
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Institute of Communications Engineering
Owning to the high peak-to-average power ratio problem, the power efficiency of orthogonal-frequency-division-multiplexing ( OFDM) systems is usually low. It deteriorates in millimeter wave systems in which the design of an efficient linear power amplifier is much more challenging. The linear-amplification-with-nonlinear-component ( LINC) technique can serve as a remedy, decomposing the input signal into two constant-envelop component signals followed by high-efficient nonlinear amplifiers. However, the power combiner, a key component used to combine the amplified signals, is difficult to implement. Combinerless LINC systems employ two transmit antennas such that two component signals can be naturally combined at the receiver. Unfortunately, the performance of combinerless LINC-OFDM systems is seriously degraded if difference, even small, exists between the two channels. The maximum likelihood ( ML) receiver can effectively solve the problem; however, its computational complexity is prohibitedly high. We propose a coded combinerless LINC-OFDM system, including a convolutional encoder and a list Viterbi algorithm ( LVA) decoder, to solve the problem. The LVA can provide a small number of candidates for the ML detector, dramatically reducing the required computational complexity. We also utilize an enhanced zero-forcing equalizer such that the soft-demapping operation can be effectively conducted. Finally, we propose a simple iterative interference cancellation scheme to further enhance the performance. Simulations show that the proposed combinerless LINC-OFDM system can outperform the conventional OFDM while the consumed power is much lower.
Spatial Control of Cell-Nanosurface Interactions by Tantalum Oxide Nanodots for Improved Implant Geometry
(2016-06-30)
Dhawan, Udesh
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Pan, Hsu An
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Lee, Chia Hui
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Chu, Ying Hao
;
Huang, Guewha Steven
Nanotopological cues can be exploited to understand the nature of interactions between cells and their microenvironment to generate superior implant geometries. Nanosurface parameters which modulate the cell behavior and characteristics such as focal adhesions, cell morphology are not clearly understood. Here, we studied the role of different nanotopographic dimensions in modulating the cell behavior, characteristics and ultimately the cell fate and accordingly, a methodology to improve implant surface geometry is proposed. Tantalum oxide nanodots of 50, 100nm dot diameter with an inter-dot spacing of 20, 70nm and heights 40, 100nm respectively, were engineered on Silicon substrates. MG63 cells were cultured for 72 hours and the modulation in morphology, focal adhesions, cell extensible area, cell viability, transcription factors and genes responsible for bone protein secretion as a function of the nanodot diameter, inter-dot distance and nanodot height were evaluated. Nanodots of 50nm diameter with a 20nm inter-dot spacing and 40nm height enhanced cell spreading area by 40%, promoted cell viability by 70% and upregulated transcription factors and genes twice as much, as compared to the 100nm nanodots with 70nm inter-dot spacing and 100nm height. Favorable interactions between cells and all dimensions of 50nm nanodot diameter were observed, determined with Scanning electron microscopy and Immunofluorescence staining. Nanodot height played a vital role in controlling the cell fate. Dimensions of nanodot features which triggered a transition in cell characteristics or behavior was also defined through statistical analysis. The findings of this study provide insights in the parameters of nanotopographic features which can vitally control the cell fate and should therefore be taken into account when designing implant geometries.
Stark Spectroscopy of Rubrene. I. Electroabsorption Spectroscopy and Molecular Parameters
(2016-06-30)
Iimori, Toshifumi
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Ito, Ryuichi
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Ohta, Nobuhiro
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Nakano, Hideyuki
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應用化學系
Electroabsorption spectroscopy investigation and the determination of molecular parameters for rubrene dispersed in a poly(methyl methacrylate) (PMMA) matrix are reported. The features of the band system in the absorption spectrum in PMMA are analogous to those in solutions. The changes in the electric dipole moment and the polarizability between the excited and ground states are determined from analysis of the Stark effect in the absorption band. The change in the transition dipole moment in the presence of an external electric field is also observed. Although rubrene is predicted to be classified as a nonpolar molecule, there is a contribution of the difference in the electric dipole moment between the excited and ground states to the electroabsorption spectrum. The origin of the nonzero difference in the electric dipole moment is argued. Stark fluorescence spectroscopy investigation is reported in Part II of this series.
ZnO-Based Microcavities Sculpted by Focus Ion Beam Milling
(2016-06-30)
Chang, Tsu-Chi
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Hong, Kuo-Bin
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Lai, Ying-Yu
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Chou, Yu-Hsun
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Wang, Shing-Chung
We reported an easy fabrication method to realize ZnO-based microcavities with various cavity shapes by focused ion beam (FIB) milling. The optical characteristics of different shaped microcavities have been systematically carried out and analyzed. Through comprehensive studies of cathodoluminescence and photoluminescence spectra, the whispering gallery mode (WGM) was observed in different shaped microcavities. Up further increasing excitation, the lasing action was dominated by these WGMs and matched very well to the simulated results. Our experiment shows that ZnO microcavities with different shapes can be made with high quality by FIB milling for specific applications of microlight sources and optical devices.
在不同模式的電腦支援協作學習環境下，師培生理解教學理論層次之差異－以Blackboard和Knowledge Forum為例
(國立交通大學傳播與科技學系和台灣資訊社會研究學會, 2016-07)
林倍伊林顯達李佩蓉詹雯靜洪國財洪煌堯
;
Pei-Yi Lin
;
Hsien-Ta Lin
;
Pei-Jung Li
;
Wen-Ching Chan
本研究旨在探究如何運用電腦支援協作學習模式，瞭解師培生在不同的資訊學習環境下對教學專業理解之差異。本研究分析師培生在不同數位平台—黑板數位學習平台（Blackboard, BB）與知識論壇平台（Knowledge Forum, KF）—上的概念學習與理解情形。研究對象為某國立大學之49位學生，研究設計將學生分為使用BB組（N=25）與使用KF組（N=24）。研究資料包含學生在BB以及KF平台上的活動，以及學生的文章內容。主要研究結果如下：第一、兩組學生在相同教師及相同課程設計下，平台上的活動量大致相同，在總文章數和總文字數上沒有顯著差異，但在回文數上，BB組的學生比KF組的學生表現較佳。第二、在教育理論與教師專業概念的高層次理解層面上，KF組學生比BB組學生表現更佳。本研究根據上述結果，進一步討論在資訊社會的趨勢下，如何運用教學科技幫助師培生對教學專業理解之能力。
Calix[4]arenes with Combined Axial Chirality and Inherent Chirality: Synthesis, Absolute Configuration and Chiral Recognition
(2016-07-01)
Zhang, Wen-Zhen
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Ma, Hui
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Xiang, Guang-Ya
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Luo, Jun
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Chung, Wen-Sheng
Calix[4]arene diastereomeric pairs with combined axial chirality and inherent chirality were readily synthesized via monoalkylation of 1,2-substituted calix[4]arene crown-4 incorporating an axially chiral binaphthyl moiety with different electrophiles as a key step. The reaction showed high generality and distinct diastereoselectivity. The easy separation of the diaster-eomers, the good diastereoselectivity of the reaction, and the poor stereoselectivity of the chiral recognition of diastereomeric pairs were attributed to the remarkable steric effect of the axially chiral binaphthyl moiety. Absolute configurations were determined by X-ray crystallography.
Removal Efficiency of Bimodal PM2.5 and PM10 by Electret Respirators and Mechanical Engine Intake Filters
(2016-07)
Chen, Sheng-Chieh
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Chang, De-Qiang
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Pei, Chenxing
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Tsai, Chuen-Jinn
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Pui, David Y. H.
As China is receiving an economic boom, PM (particulate matter) pollutions not only have become a serious regional problem but also frequently impacted its neighboring counties, e.g., Korea and Japan. In addition to its adverse effects on human health, the on-and off-road engines operated in ambient can also be affected. In this study, a simple system for generating simulated ambient bimodal PMs comprising fine (PM2.5), coarse (PM2.5-10) particles was developed for evaluating the initial efficiency of seven respirator and four engine intake filters. In addition to the size fractional efficiency curves for each filter media determined from the SMPS (scanning mobility particle sizer) and APS (aerodynamic particle sizer), both number and mass based efficiency of these filters for PM2.5, PM2.5-10 and PM10 were also obtained to evaluate their performances against ambient PM pollutions. Data showed that the engine intake filters had a low efficiency for both mass and number based PM2.5, which was only about 25-30%. However, there was a large difference between their number and mass based PM10 efficiency. The former was much lower than the latter because these filters are with high efficiency only for coarse particles. Besides, the most of particles in number was resided in the fine size range while the mass was in coarse size range. For the respirator filtration tests, results showed that most of them can effectively remove both PM2.5 and PM10, in which the mass efficiency was always higher than that of number. The PM2.5 number efficiency results showed there are three out of seven respirator filters are with N-95 rated level, in which the efficiency of their most penetrating particle size is higher than 95%. The current simple experimental system could be applied to examine different purpose filters which protect human health and outdoor engines against ambient PM2.5 and PM10.
Profile of achievement goals in mathematics: A two-year study with cognitive and affective outcomes
(2016-07-01)
Chen, Ssu-Kuang
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Lo, Meng-Ting
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Lin, Sunny S. J.
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教育研究所
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Institute of Education
【校友動態】夏日釣遊趣
(國立陽明大學牙醫校友會, 2016-07)
林培堯
Optimal Floating Gate Potential for Extending Data Retention of Post-Baking Method in Sub-20 nm Triple Level per Cell NAND Flash Memory
(2016-07)
Hsu, Yu-Cheng
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Lin, Wei
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Chang, Chun-Yen
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電機學院
;
電子工程學系及電子研究所
A post-baking method with an optimized data pattern is developed to eliminate the program/erase (PE) cycle-induced damage of sub-20 nm NAND Flash memory and to improve its reliability. The electric field of the tunneling oxide (E-ox)-dependent oxide recovery is discussed in detail. The experimental results reveal that additional traps in the tunneling oxide are induced by the E-ox during the baking process via an electron-phonon interaction and the effectiveness of oxide recovery is reduced by the generation of these additional traps. Hence, the additional traps degrade the read margin and retention ability. Therefore, an optimized data pattern is produced to minimize E-ox and reduce the number of additional traps formed during the post-baking process. When the optimized data pattern is utilized in post-baking, the endurance of the sub-20 nm three-level-per-cell (TLC) NAND Flash memory is quadruple improved under one year retention condition.
Electrochemical decolorization of dye wastewater by surface-activated boron-doped nanocrystalline diamond electrode
(2016-07)
Chen, Chienhung
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Nurhayati, Ervin
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Juang, Yaju
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Huang, Chihpin
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環境工程研究所
Complex organics contained in dye wastewater are difficult to degrade and often require electrochemical advanced oxidation processes (EAOPs) to treat it Surface activation of the electrode used in such treatment is an important factor determining the success of the process. The performance of boron-doped nanocrystalline diamond (BD-NCD) film electrode for decolorization of Acid Yellow (AY-36) azo dye with respect to the surface activation by electrochemical polarization was studied. Anodic polarization found to be more suitable as electrode pretreatment compared to cathodic one. After anodic polarization, the originally H-terminated surface of BD-NCD was changed into 0-terminated, making it more hydrophilic. Due to the oxidation of surface functional groups and some portion of sp2 carbon in the BD-NCD film during anodic polarization, the electrode was successfully being activated showing lower background current, wider potential window and considerably less surface activity compared to the non-polailzed one. Consequently, electrooxidation (E0) capability of the anodically-polarized BD-NCD to degrade AY-36 dye was significantly enhanced, capable of nearly total decolorization and chemical oxygen demand (COD) removal even after several times of re-using. The BD-NCD film electrode favored acidic condition for the dye degradation; and the presence of chloride ion in the solution was found to be more advantageous than sulfate active species. (C) 2016 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
Superior Data Retention for Sub-20 nm Triple Level Per Cell NAND Flash Memory by Using a Novel Data Programming Method
(2016-07)
Lin, Wei
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Chang, Chun-Yen
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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
This work presents a novel data programming method for sub-20 nm triple level per cell (TLC) NAND Flash memory. The proposed method improves data retention ability and reduces the data failure rate of Embedded Multi Media Card (eMMC) during the high temperature reflow of surface mount technology (SMT). More than owing to the high temperature stress, the failure is closely related to the data pattern of the adjacent cell array. The proposed data programming method generates an optimized dummy data pattern based on the data of the last data word line (WL) and, then, programs the optimized dummy data pattern to the word line next to the data edge one to suppress the abrupt electrical potential energy drops caused by the erase data. The graded electrical potential energy can thus reduce the electric field and electron tunneling probability. Furthermore, the row bit error rate (RBER) with the high temperature stress of the last data word line can be reduced 85% by using the novel data programming method. This work also attempts to identify the root cause of the temperature and adjacent data pattern dependent retention by measuring and performing statistical analysis of a sub-20 nm TLC NAND Flash memory chip. 3D numerical simulation with comprehensive quantum tunneling models is also conducted to facilitate the theoretical analysis. Statistical and numerical analysis results indicate that a severe threshold voltage (Vth) shift of the memory cell occurs when the adjacent floating gate (FG) has both high and low Vth states. Above results demonstrate the feasibility of the proposed data programming method in generating the optimized dummy data pattern.
【校友動態】留給世界陽光璀璨的笑臉
(國立陽明大學牙醫校友會, 2016-07)
慈濟醫療人文月刊
Solution p-doped fluorescent polymers for enhanced charge transport of hybrid organic-silicon nanowire photovoltaics
(2016-07)
Tsai, Pei-Ting
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Li, Ming-Chin
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Lai, Yi-Chun
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Tseng, Wei-Hsuan
;
Wu, Chih-I
The solution p-type doping of various conjugated polymers and small molecules via blending with tetrafluorotetracyano-quinodimethane (F4-TCNQ) is investigated to facilitate hole transport for hybrid organic-silicon-nanowire solar cells. Among all, the highly-fluorescent conjugated polymers such as poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) demonstrate superior transport characteristics, where both the device fill-factor and power conversion efficiency (PCE) are positively correlated with the doping concentration. The best PCE achieves 13.66% from the device with 30% p-doped PFO, compared to the reference at 12.50%. The enhancement is ascribed to the efficient interfacial charge-carrier recombination with minimal energy losses. A vertically graded doping profile is further revealed with F4-TCNQ molecules preferentially accumulated near the silicon surface. (C) 2016 Elsevier B.V. All rights reserved.
Optimal Distributed Codes for Feedback-Aided Cooperative Relay Networks
(2016-07)
Lu, Hsiao-Feng (Francis)
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電機學院
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College of Electrical and Computer Engineering
A novel transmission scheme for cooperative relay networks is presented in this paper. The proposed scheme is based on the non-orthogonal selection decode-and-forward protocol with an additional assumption of having a low rate feedback channel from the destination to relays. Benefited from the feedback information, an optimal distributed code that has an extremely short delay equal to four is constructed, and the same code is applicable to networks with the arbitrary number of relays to yield optimal cooperative diversity. The proposed code is sphere decodable with a decoding complexity again independent of the number of relays in high SNR regime. In particular, when operating at multiplexing gain >=(1/2), the lattice decoder at the destination has a zero complexity exponent, meaning a constant decoding complexity and independent of transmission rate. Analyses for the decoding complexity of other existing diversity-optimal distributed codes are also provided. It is shown that these codes have a linear growth in delay and an exponential growth in decoding complexity as the number of relays increases.
Au-Free GaN High-Electron-Mobility Transistor with Ti/Al/W Ohmic and WN (X) Schottky Metal Structures for High-Power Applications
(2016-07)
Hsieh, Ting-En
;
Lin, Yueh-Chin
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Chu, Chung-Ming
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Chuang, Yu-Lin
;
Huang, Yu-Xiang
In this study, an Au-free AlGaN/GaN high-electron-mobility transistor (HEMT) with Ti/Al/W ohmic and WNx Schottky metal structures is fabricated and characterized. The device exhibits smooth surface morphology after metallization and shows excellent direct-current (DC) characteristics. The device also demonstrates better performance than the conventional HEMTs under high voltage stress. Furthermore, the Au-free AlGaN/GaN HEMT shows stable device performance after annealing at 400A degrees C. Thus, the Ti/Al/W ohmic and WN (X) Schottky metals can be applied in the manufacturing of GaN HEMT to replace the Au based contacts to reduce the manufacturing costs of the GaN HEMT devices with comparable device performance.
Managing a Very Connected World: A Report on APNOMS2015
(2016-07)
Kim, Myung-Sup
;
Kamiyama, Noriaki
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Yi, Chih-Wei
;
Hong, Won-Kyu
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Tonouchi, Toshio
This article presents a report on APNOMS2015, which was held August 19-21, 2015 in Busan, Korea. The theme of APNOMS2015 was "Managing a Very Connected World.".