Browsing by Issue Date, starting with "2012-04-13"

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Fabrication and resistive switching characteristics of high compact Ga-doped ZnO nanorod thin film devices
(2012-04-13)
Yao, I-Chuan
;
Lee, Dai-Ying
;
Tseng, Tseung-Yuen
;
Lin, Pang
;
材料科學與工程學系
This study investigates the resistive switching behavior of Ga-doped ZnO (GZO) nanorod thin films with various Ga/Zn molar ratios. Vertically well-aligned and uniform GZO nanorod thin films were successfully grown on Au/Ti/SiO2/p-Si substrates using an aqueous solution method. X-ray diffraction (XRD) results indicate that GZO nanorods have [0001] highly preferred orientation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show the formation of highly ordered and dense nanorod thin films. These compact GZO nanorod thin films can be used to make resistive switching memory devices. Such memory devices can be reversibly switched between ON and OFF states, with a stable resistance ratio of ten times, narrow dispersion of ON and OFF voltages, and good endurance performance of over 100 cycles. The resistive switching mechanism in these devices is related to the formation and rupture of conducting filaments consisting of oxygen vacancies, occurring at interfaces between GZO nanorods (grain boundaries). Results show that the resulting compact GZO nanorod thin films have a high potential for resistive memory applications.
Synthesis of Main-Chain Metallo-Copolymers Containing Donor and Acceptor Bis-Terpyridyl Ligands for Photovoltaic Applications
(2012-04-13)
Padhy, Harihara
;
Ramesh, Mohan
;
Patra, Dhananjaya
;
Satapathy, Rudrakanta
;
Pola, Murali Krishna
Two random (ZnII-based P1P2) and two alternating (RuII-based P3P4) metallo-copolymers containing bis-terpyridyl ligands with various central donor (i.e., fluorene or carbazole) and acceptor (i.e., benzothiadiazole) moieties were synthesized. The effects of electron donoracceptor interactions with metal (ZnII and RuII) ions on their thermal, optical, and electrochemical properties were investigated. Because of the strong ICT transitions between donor and acceptor ligands in both ZnII- and RuII-based metallo-coplymers and MLCT transitions in RuII-based metallo-coplymers, the absorption spectra covered a broad range of 260750 nm with the band gaps of 1.571.77 eV. In addition, the introduction of RuII-based metallo-coplymer P4 mixed with PC60BM as an active layer of the BHJ solar cell device exhibited the highest PCE value up to 0.90%.
Applications of parametric processes to high-quality multicolour ultrashort pulses, pulse cleaning and CEP stable sub-3fs pulse
(2012-04-14)
Kobayashi, Takayoshi
;
Liu, Jun
;
Okamura, Kotaro
;
電子物理學系
;
Department of Electrophysics
Our recent experimental results of three methods related to and useful for the generation of attosecond pulses are summarized. The pulses obtained by all of them have high qualities in terms of phase, temporal, spectral and spatial properties which are based on the physical principles associated with the parametric processes. First, carrier-envelope phase (CEP) stable sub-5 fs and sub-3 fs pulses by non-collinear optical parametric amplification (NOPA) in the near-infrared and visible spectral range will be described. The mechanism of the passive CEP stabilization is described. Passively stabilized idler and its second harmonic (SH) pulses from NOPAs are compressed to sub-5fs and sub-3fs, respectively. Compression of the idler output from a NOPA and its SH is attained with a specially designed characterization method during the compression. Second, generation of multicolour pulses by the cascaded four-wave mixing process in bulk media is discussed. As short as 15-fs multicoloured femtosecond pulses are obtained with two similar to 40 fs pulses incident to a fused-silica glass plate by this method. These broadband multicolour sidebands are expected to provide single-cycle or sub-fs pulses after the Fourier synthesis. Third, a new technique based on self-diffraction in the Kerr medium is used to clean and shorten the femtosecond laser pulse. The cleaned pulse with high temporal contrast is expected to be used as a seed for a background-free petawatt laser system and then used as the laser source for high-energy attosecond pulse generation in a solid target. The mechanisms of CEP stabilization, pulse spectral smoothening and pulse contrast enhancement are comparatively discussed.
Franck-Condon simulation of vibrationally resolved optical spectra for zinc complexes of phthalocyanine and tetrabenzoporphyrin including the Duschinsky and Herzberg-Teller effects
(2012-04-14)
Guo, Meiyuan
;
He, Rongxing
;
Dai, Yulan
;
Shen, Wei
;
Li, Ming
High resolved absorption and fluorescence spectra of zinc complexes of phthalocyanine (ZnPc) and tetrabenzoporphyrin (ZnTBP) in the region of Q states were reported. Few theoretical investigations were performed to simulate the well-resolved spectra and assigned the vibrational bands of the large molecules, especially for high symmetrical characteristic molecules, on account of the difficulties to optimize the excited states and analyze a large number of final vibrational-normal modes. In the present work, the S-0 <-> S-1 absorption and fluorescence spectra (that is, the Q band) of ZnPc and ZnTBP were simulated using time-dependent density functional theory with the inclusions of Duschinsky and Herzberg-Teller contributions to the electronic transition dipole moments. The theoretical results provide a good description of the optical spectra and are proved to be in excellent agreement with experimental spectra in inert-gas matrices or in supersonic expansion. This study focused attentions on the optical spectral similarities and contrasts between ZnPc and ZnTBP, in particular the noticeable Duschinsky and Herzberg-Teller effects on the high-resolved absorption and fluorescence spectra were considered. Substitution of meso-tetraaza on the porphyrin macrocycle framework could affect the ground state geometry and alter the electron density distributions, the orbital energies that accessible in the Q band region of the spectrum. The results were used to help interpret both the nature of the electronic transitions in Q band region, and the spectral discrepancies between phthalocyanine and porphyrin systems. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3703310]
A Structured Quasi-Arnoldi procedure for model order reduction of second-order systems
(2012-04-15)
Li, Yung-Ta
;
Bai, Zhaojun
;
Lin, Wen-Wei
;
Su, Yangfeng
;
應用數學系
Existing Krylov subspace-based structure-preserving model order reduction methods for the second-order systems proceed in two stages. The first stage is to generate a basis matrix of the underlying Krylov subspace. The second stage is to employ an explicit subspace projection to obtain a reduced-order model with a moment-matching property. An open problem is how to avoid explicit projection so that it will be efficient for truly large scale systems. In addition, it is also desired that a structure-preserving reduced system of order n matches maximum 2n moments. In this paper we propose a new procedure to compute a so-called Structured Quasi-Arnoldi (SQA) decomposition. Once the SQA decomposition is computed, a structure-preserving reduced-order model can be defined immediately from the decomposition without the explicit subspace projection. Furthermore, the reduced model of order n matches maximum 2n moments. Numerical examples demonstrate that the transpose-free SQA-based reduced model is compatible with the two-sided structure-preserving explicit projection methods and is more accurate than the one-sided structure-preserving explicit projection methods due to the higher number of matched moments. (C) 2011 Elsevier Inc. All rights reserved.
On the structure of multi-layer cellular neural networks
(2012-04-15)
Ban, Jung-Chao
;
Chang, Chih-Hung
;
Lin, Song-Sun
;
應用數學系
;
Department of Applied Mathematics
Let Y subset of {-1, 1}(Z infinity xn) be the mosaic solution space of an n-layer cellular neural network. We decouple Y into n subspaces, say Y-(1), Y-(2), ... , Y-(n), and give a necessary and sufficient condition for the existence of factor maps between them. In such a case, Y-(i) is a sofic shift for 1 <= i <= n. This investigation is equivalent to study the existence of factor maps between, two sofic shifts. Moreover, we investigate whether Y-(i) and Y-(j) are topological conjugate, strongly shift equivalent, shift equivalent, or finitely equivalent via the well-developed theory in symbolic dynamical systems. This clarifies, in a multi-layer cellular neural network, each layer's structure. As an extension, we can decouple Y into arbitrary k-subspaces. where 2 <= k <= n, and demonstrates each subspace's structure. (C) 2012 Elsevier Inc. All rights reserved.
Optical trapping and polarization-controlled scattering of dielectric spherical nanoparticles by femtosecond laser pulses
(2012-04-15)
Usman, Anwar
;
Chiang, Wei-Yi
;
Masuhara, Hiroshi
;
應用化學系
;
應用化學系分子科學碩博班
We present optical trapping behavior of 50-nm-sized polystyrene beads, suspended in water medium, by femtosecond pulsed laser beam. In addition to a higher number of nanoparticles trapped at the focal spot by the ultrashort laser pulses compared with that by continuous-wave laser, the nanoparticles are scattered out of the focal spot by the laser pulses to the surrounding area. The scattered particles form a partially opened folding fan-shaped bright locus in two opposite directions, in an alternating manner, perpendicular to the laser polarization. To understand those phenomena, we analyzed radiation (gradient and scattering) force of femtosecond laser pulses and their temporal force exerted on the dielectric spherical nanoparticles by taking into account the impulsive peak power and the axial component of electric light field produced by high numerical aperture of objective lens. We show that the axial electric field is responsible for lateral components of the scattering and temporal forces, and hence, controls the scattering directions of the Rayleigh particles. These findings provide important information about the dynamic optical trapping of the Rayleigh particles by highly focused ultrashort laser pulses. (c) 2012 Elsevier B.V. All rights reserved.
Rapid and efficient purification of chrysophanol in Rheum Palmatum LINN by supercritical fluid extraction coupled with preparative liquid chromatography in tandem
(2012-04-15)
Lo, Tiffany Chien-Ting
;
Nian, Hung-Chi
;
Chiu, Kong-Hwa
;
Wang, Ai-Yih
;
Wu, Ben-Zen
Chrysophanol has high pharmaceutical values. However, it was difficult to use the traditional extraction method to extract high-concentration chrysophanol. Therefore, the purpose of this study is to purify and separate chrysophanol in traditional herb, Rheum Palmatum LINN, by using supercritical fluid extraction (SFE) and preparative high-performance liquid chromatography (P-HPLC) for rapid and large-scale isolation. The method is efficient for selective extraction of chrysophanol from the herbs, which have complex compositions. The extraction efficiency of chrysophanol with SFE is 25x higher than that of boiled water extraction under the same extraction time. The optimal conditions for SFE were 210 atm and 85 degrees C for 30 min; for P-HPLC, a C18 column was used with a gradient elution of methanol and 1% acetic acid at a flow rate of 10 mL/min. According to H-1 NMR and LC-MS analyses, the purity of the isolated chrysophanol was as high as 99%. The recovery for chrysophanol in Rheum after SPE/PHPLC processing was in the range of 88-91.5%. Compared with other extraction and purification methods, the sequential system (SFE/PHPLC) achieved the highest amount of extracted chrysophanol from Rheum Palmatum LINN (0.38 mg/g) and the shortest run time (3 h). Hence, this rapid and environmentally friendly method can separate compounds based on polarity with high efficiencies and, coupled with P-HPLC, it may be applicable in the large-scale production of foods and medicines in the future. (C) 2012 Elsevier B.V. All rights reserved.
Preface to the special issue in honor of Monique M. Martin
(2012-04-15)
Plaza, Pascal
;
Masuhara, Hiroshi
;
交大名義發表
;
National Chiao Tung University
Identifying transcriptional start sites of human microRNAs based on high-throughput sequencing data
(2012-04-15)
Tsou, Ann-Ping
;
Chien, Chia-Hung
;
Chiang-Hsieh, Pei-Yun
;
Tsai, Wei-Chih
;
Huang, Hsien-Da
具有氧化鐠之介電結構、具有氧化鐠之電晶體及其製造方法
(2012-04-16)
張翼
;
林岳欽
本發明係揭露一種具有氧化鐠之介電結構、具有氧化鐠之電晶體及其製造方法，該具有氧化鐠之電晶體係至少包含一三五族基板、一閘極介電層及一閘極。其中，閘極介電層係設於三五族基板上，閘極則設於閘極介電層上，而介電層係為氧化鐠（PrxOy）。本發明藉由使用具有高介電係數以及高能隙之氧化鐠（Pr6O11）作為介電層材料，除了有效的抑制漏電流外，更可進一步降低以三五族材料作為基板的元件之等效氧化物厚度（EOT）。
擴散光學斷層掃瞄之重疊／組合影像重建方法、裝置及程式產品
(2012-04-16)
蔡彰哲
;
方偉騏
一種擴散光學斷層掃瞄之重疊/組合影像重建方法，包含下述步驟：(a)建立至少一在預定範圍選擇多個待處理的子區域的處理模式；(b)對各子區域取得一部分光線強度矩陣；(c)對各子區域以前算模型取得一部分權重矩陣，並利用奇異分解法換算一部分權重逆矩陣；(d)將各子區域之部分光線強度矩陣與部分權重逆矩陣相乘得到各子區域之部分吸收係數矩陣；及(e)將各子區域之部分吸收係數矩陣依位置重疊/組合。
垂直式感測器
(2012-04-16)
冉曉雯
;
孟心飛
;
戴銘志
;
趙宇強
一種垂直式感測器，係包括：基板；第一電極層，係形成於該基板上；感測層，係形成於該第一電極層上，且令該第一電極層夾置於該基板與感測層之間，其中，該感測層係選自對待測物質有反應的材料或具有對待測物質有反應之部位的材料；以及第二電極層，係形成於該感測層上，並令該感測層夾置於該第一電極層與第二電極層之間，且該第二電極層具有複數孔洞，以供該待測物質接觸該感測層。本發明之垂直式感測器提供即時、靈敏及快速之偵測性能。
可容忍閘極崩毀之功率閘結構
(2012-04-16)
楊皓義
;
莊景德
;
黃威
本發明提供一種可容忍閘極崩毀之功率開關結構，其連接於一靜態隨機存取記憶體，功率閘結構包含第一互補式金氧半電晶體(CMOS)開關及第二互補式金氧半電晶體(CMOS)開關，兩者為不同閘極厚度或不同臨界電壓，利用正常閘極厚度或正常臨界電壓提供靜態隨機存取記憶體從睡眠模式或待機模式切換至啟動模式所需之電流；利用較厚的閘極厚度或較高臨界電壓提供予靜態隨機存取記憶體在工作模式所需之電流，藉以避免功率開關閘極崩毀的發生，進而影響靜態隨機存取記憶體的雜訊增益邊界、穩定性與效能。
Visible-light photocatalytic activity of Ni-doped TiO2 from ab initio calculations
(2012-04-16)
Lin, Yan-Ming
;
Jiang, Zhen-Yi
;
Zhu, Chao-Yuan
;
Hu, Xiao-Yun
;
Zhang, Xiao-Dong
The geometrical structures and electronic properties of Ni-doped anatase and rutile TiO2 were successfully calculated and simulated by a plane wave pseudopotential method based on density functional theory (OFT). Our results show that most Ni 3d states are located in the forbidden band of substitutional Ni to O-doped anatase and rutile TiO2, and mix with O 2p states, resulting in a decrease of the photon excitation energy and red-shift of absorption edge compared to pure anatase and rutile. For substitutional Ni to Ti-doped anatase TiO2 under O-rich growth condition, the band gap has a slight decline of about 0.05 eV compared with pure anatase TiO2 and contains a series of impurity energy levels, which may be responsible for the experimental photocatalytic activity and red-shift of absorption edge. (C) 2012 Elsevier B.V. All rights reserved.
多相機環境之人物追蹤連結系統及其方法
(2012-04-16)
張意政
;
黃仲陵
;
劉杰宇
;
王勝毓
本發明提供一種多相機環境之人物追蹤連結系統及其方法,其係包含了三個主要流程:第一部份首先建立相機之監控區域中的進出口,及訓練人物在進出口間的時間空間機率分佈,並據以連結人物移動的追蹤軌跡;第二部份為以動態規劃為基礎之回溯追尋,對追蹤軌跡中的遺失軌跡進行第一次的補償性連結;第三部份為利用隱藏式馬可夫模型訓練之常態路徑,對所連接之移動軌跡進行辨識及重新組合,並對遺失軌跡進行第二次的補償性連結。
Novel Active Personal Nanoparticle Sampler for the Exposure Assessment of Nanoparticles in Workplaces
(2012-04-17)
Tsai, Chuen-Jinn
;
Liu, Chun-Nan
;
Hung, Shao-Ming
;
Chen, Sheng-Chieh
;
Uang, Shi-Nian
A novel active personal nanoparticle sampler (PENS), which enables the collection of both respirable particulate mass (RPM) and nanoparticles (NPs) simultaneously, was developed to meet the critical demand for personal sampling of engineered nanomaterials (ENMs) in workplaces. The PENS consists of a respirable cyclone and a micro-orifice impactor with the cutoff aerodynamic diameter (d(pa50)) of 4 mu m and 100 nm, respectively. The micro-orifice impactor has a fixed micro-orifice plate (137 nozzles of 55 mu m in the inner diameter) and a rotating, silicone oil-coated Teflon filter substrate at 1 rpm to achieve a uniform particle deposition and avoid solid particle bounce. A final filter is used after the impactor to collect the NPs. Calibration results show that the d(pa50) of the respirable cyclone and the micro-orifice impactor are 3.92 +/- 0.22 mu m and 101.4 +/- 0.1 nm, respectively. The d(pa50) at the loaded micro-Al2O3 mass of 0.36-3.18 mg is shifted to 102.9-101.2 nm, respectively, while it is shifted to 98.9-97.8 nm at the loaded nano-TiO2 mass of 0.92-1.78 mg, respectively. That is, the shift of d(pa50) due to solid particle loading is small if the PENS is not overloaded. Both NPs and RPM concentrations were found to agree well with those of the IOSH respirable cyclone and MOUDI. By using the present PENS, the collected samples can be further analyzed for chemical species concentrations besides gravimetric analysis to determine the actual exposure concentrations of ENMs in both RPM and NPs fractions in workplaces, which are often influenced by the background or incident pollution sources.
Patient-oriented simulation based on Monte Carlo algorithm by using MRI data
(2012-04-17)
Chuang, Ching-Cheng
;
Lee, Yu-Tzu
;
Chen, Chung-Ming
;
Hsieh, Yao-Sheng
;
Liu, Tsan-Chi
Background: Although Monte Carlo simulations of light propagation in full segmented three-dimensional MRI based anatomical models of the human head have been reported in many articles. To our knowledge, there is no patient-oriented simulation for individualized calibration with NIRS measurement. Thus, we offer an approach for brain modeling based on image segmentation process with in vivo MRI T1 three-dimensional image to investigate the individualized calibration for NIRS measurement with Monte Carlo simulation. Methods: In this study, an individualized brain is modeled based on in vivo MRI 3D image as five layers structure. The behavior of photon migration was studied for this individualized brain detections based on three-dimensional time-resolved Monte Carlo algorithm. During the Monte Carlo iteration, all photon paths were traced with various source-detector separations for characterization of brain structure to provide helpful information for individualized design of NIRS system. Results: Our results indicate that the patient-oriented simulation can provide significant characteristics on the optimal choice of source-detector separation within 3.3 cm of individualized design in this case. Significant distortions were observed around the cerebral cortex folding. The spatial sensitivity profile penetrated deeper to the brain in the case of expanded CSF. This finding suggests that the optical method may provide not only functional signal from brain activation but also structural information of brain atrophy with the expanded CSF layer. The proposed modeling method also provides multi-wavelength for NIRS simulation to approach the practical NIRS measurement. Conclusions: In this study, the three-dimensional time-resolved brain modeling method approaches the realistic human brain that provides useful information for NIRS systematic design and calibration for individualized case with prior MRI data.
酸化プラセオジムを備えた誘電体、酸化プラセオジムを備えたトランジスタ及びその製造方法
(2012-04-19)
張翼
;
林岳欽
【課題】酸化プラセオジムの誘電体、酸化プラセオジムを備えたトランジスタ及びその製造方法を提供し、以って半導体素子のリーク電流及び等価酸化物膜厚の過大の問題を解決すること。【解決手段】本発明では、酸化プラセオジムを備えたトランジスタは、少なくとも一つのIII－Ｖ族基板と、一つのゲート誘電層と、一つのゲート電極とを含む。また、III－Ｖ族基板にゲート誘電層が設けられ、ゲート誘電層にゲート電極が設けられ、誘電層は酸化プラセオジム（ＰｒxＯy）である。本発明は、誘電層材料として高誘電率及び高エネルギーギャップを備えた酸化プラセオジム（Ｐｒ6Ｏ11）を用いることにより、リーク電流を有効に抑制する外、更にIII－Ｖ族材料を基板とした素子の等価酸化膜厚（ＥＯＴ）を薄くさせることもできる。【選択図】図４
SPATIALLY PRE-PROCESSED TARGET-TO-JAMMER RATIO WEIGHTED FILTER AND METHOD THEREOF
(2012-04-19)
HU JWU-SHENG
;
LEE MING-TANG
The present invention provides a spatially pre-processed target-to-jammer ratio weighted filter and a method thereof, which uses two microphones to receive audio signals. The audio signals are divided into a plurality of sinusoidal waves by a fast Fourier transform (FFT) module, and a beamformer uses the sinusoidal waves to generate beamformed signals. A reference generator generates at least one reference signal. The beamformed signals and reference signals are used to work out power spectral densities (PSD), and a target-to-jammer ratio (TJR) is worked out with the power spectral densities. TJR is used to determine whether a sound source exists. According to the determination result, a noise estimator is switched to eliminate noise from the beamformed signals and generate output signals. An inverse fast Fourier transform (IFFT) module recombines the output signals and then outputs the recombined signals.