Browsing by Author "Kuo, Chih-Wei"

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Assembly of Dimethyl Acetylenedicarboxylate and Phosphanes with Aldehydes Leading to gamma-Lactones Bearing alpha-Phosphorus Ylides as Wittig Reagents
(2012-10-01)
Deng, Jie-Cheng
;
Chan, Fu-Wei
;
Kuo, Chih-Wei
;
Cheng, Chun-An
;
Huang, Chien-Yu
We report herein a convenient route to the synthesis of aryl-substituted ?-lactones bearing an a-phosphorus ylide moiety through the assembly of dimethyl acetylenedicarboxylate (DMAD), electron-deficient aldehydes, and triaryl- or trialkylphosphanes in moderate to good yields. The formation of ?-lactones is highly dependent on the reaction time, the phosphane nucleophile, and the molar ratio of DMAD, aldehyde, and phosphane. We found that reactions with a DMAD/aldehyde/tri-p-tolylphosphane molar ratio of 3:1:6 and more electron-deficient aldehydes, such as 4-nitrobenzaldehyde and 4-chloro-3-nitrobenzaldehyde, gave good yields. The isolated ylides reacted with aldehydes as Wittig reagents to give olefins in moderate yields.
Development of Limited-Angle Iterative Reconstruction Algorithms with Context Encoder-Based Sinogram Completion for Micro-CT Applications
(2018-12-01)
Jin, Shih-Chun
;
Hsieh, Chia-Jui
;
Chen, Jyh-Cheng
;
Tu, Shih-Huan
;
Chen, Ya-Chen
Limited-angle iterative reconstruction (LAIR) reduces the radiation dose required for computed tomography (CT) imaging by decreasing the range of the projection angle. We developed an image-quality-based stopping-criteria method with a flexible and innovative instrument design that, when combined with LAIR, provides the image quality of a conventional CT system. This study describes the construction of different scan acquisition protocols for micro-CT system applications. Fully-sampled Feldkamp (FDK)-reconstructed images were used as references for comparison to assess the image quality produced by these tested protocols. The insufficient portions of a sinogram were inpainted by applying a context encoder (CE), a type of generative adversarial network, to the LAIR process. The context image was passed through an encoder to identify features that were connected to the decoder using a channel-wise fully-connected layer. Our results evidence the excellent performance of this novel approach. Even when we reduce the radiation dose by 1/4, the iterative-based LAIR improved the full-width half-maximum, contrast-to-noise and signal-to-noise ratios by 20% to 40% compared to a fully-sampled FDK-based reconstruction. Our data support that this CE-based sinogram completion method enhances the efficacy and efficiency of LAIR and that would allow feasibility of limited angle reconstruction.
Joint Base Station Association and Radio Resource Allocation for Downlink Carrier Aggregation in LTE-Advanced Systems
(2015)
Li, Pei-Rong
;
Kuo, Chih-Wei
;
Feng, Kai-Ten
;
Chang, Tain-Sao
;
電機學院
The deployment of small cells with carrier aggregation (CA) technique is a significant feature of next-generation cellular networks. The potential benefits of dense base stations (BSs) deployment are provided by using proper interference management mechanisms. Meanwhile, the user equipments (UEs) can simultaneously access multiple component carriers (CCs) to meet the dramatically increased traffic demand by means of CA. In this paper, an optimization problem consists of UE-BS association, CC configuration, frequency resources scheduling, and power allocation with adaptive modulation schemes is investigated to enhance energy efficiency, focusing on the quality of service (QoS)-aware CA. To obtain the near-optimal solutions as well as the consideration of computational complexity, a cross-entropy-based algorithm (CEA) is proposed to jointly solve the combinatorial problem. Compared to the traditional heuristic algorithms, the merits of proposed scheme can be observed via simulation results.
Nucleophilic conjugate 1,3-addition of phosphines to oligoynoates
(2014)
Deng, Jie-Cheng
;
Kuo, Chih-Wei
;
Chuang, Shih-Ching
;
應用化學系
;
Department of Applied Chemistry
Herein we have elucidated unusual and unique nucleophilic conjugate 1,3-addition reactions of surveyed oligoynoates toward phosphines through spectroscopic and single crystal X-ray diffraction analyses of three-component reaction products of oligoynoates, phosphines and aldehydes.
Transition of stable rectification to resistive-switching in Ti/TiO(2)/Pt oxide diode
(2010-06-28)
Huang, Jiun-Jia
;
Kuo, Chih-Wei
;
Chang, Wei-Chen
;
Hou, Tuo-Hung
;
電機工程學系
We have fabricated a Ti/TiO(2)/Pt oxide diode with excellent rectifying characteristics by the asymmetric Schottky barriers at the Ti/TiO(2) (0.13 eV) and the TiO(2)/Pt (0.73 eV) interfaces. Instead of homogeneous conduction, the current transport is governed by the localized oxygen-deficient TiO(2) filaments. In addition, the reproducible resistive-switching exists in the same structure, triggered by the forming process. The transition between two modes is ascribed to the destruction of the interface barriers at forming. The rectification stable up to 125 degrees C and 10(3) cycles under +/- 3 V sweep without interference with resistive-switching shows satisfactory reliability of TiO(2) diodes for one diode-one resistor memory devices. (C) 2010 American Institute of Physics. [doi:10.1063/1.3457866]
Transition of stable rectification to resistive-switching in Ti/TiO2/Pt oxide diode
(2010-06-28)
Huang, Jiun-Jia
;
Kuo, Chih-Wei
;
Chang, Wei-Chen
;
Hou, Tuo-Hung
;
電子工程學系及電子研究所
We have fabricated a Ti/TiO2/Pt oxide diode with excellent rectifying characteristics by the asymmetric Schottky barriers at the Ti/TiO2 (0.13 eV) and the TiO2/Pt (0.73 eV) interfaces. Instead of homogeneous conduction, the current transport is governed by the localized oxygen-deficient TiO2 filaments. In addition, the reproducible resistive-switching exists in the same structure, triggered by the forming process. The transition between two modes is ascribed to the destruction of the interface barriers at forming. The rectification stable up to 125 degrees C and 10(3) cycles under +/- 3 V sweep without interference with resistive-switching shows satisfactory reliability of TiO2 diodes for one diode-one resistor memory devices. (C) 2010 American Institute of Physics. [doi:10.1063/1.3457866]
Uncover nucleophilic conjugate 1,3-addition of phosphines to polyynoates
(2014-08-10)
Chuang, Shih-Ching
;
Deng, Jie-Cheng
;
Kuo, Chih-Wei
;
應用化學系
;
Department of Applied Chemistry