Browsing by Author "Chen, Kuan-Wei"

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Controlled synthesis and CO sensing potentials of size-tunable highly-uniform mesoporous Co3O4 nanospheres
(2020-03-05)
Chen, Kuan-Wei
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Tsai, Ju-Heng
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Chen, Chun-Hua
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材料科學與工程學系
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Department of Materials Science and Engineering
A series of highly-uniform and mesoporous Co3O4 nanospheres comprising porously-assembled tiny building blocks, and more importantly, with widely tunable sizes from 50 nm up to 500 nm were successfully synthesized for the first time via single facile polyol approach. The crucial synthesizing factors including molecular weight and concentrations of polyvinylpyrrolidone, the fraction of cobalt precursor, and the subsequent calcination temperature and time were systematically varied over a very wide range for extensively understanding their effects on growth mechanisms, uniformity and particularly the minimum assembled size. The present unique mesoporous nanoassemblies evidently lead to not only a higher surface-to-volume ratio for a variety of potential applications but a lower operating temperature for CO sensing compared with that reported for a variety of intrinsic or heterogeneous Co3O4 nanostructures. (C) 2019 Elsevier B.V. All rights reserved.
Controlled synthesis of Pt and Co3O4 dual-functionalized In2O3 nanoassemblies for room temperature detection of carbon monoxide
(2018-10-21)
Chen, Kuan-Wei
;
Liu, Jen-Pu
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Hsu, Yu-Shan
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Liu, Chao-Heng
;
Pai, Ying-Hao
We have designed and successfully synthesized innovative Pt and Co3O4 nanostructure co-decorated In2O3 nano-branches via stepwise facile chemical approaches for room-temperature CO gas sensing. The present results indicate that the combination of well-dispersed tiny Pt nanoparticles and the secondary oxide, p-type Co3O4, nanostructures with optimized fractions onto the n-type In2O3 nano-branches is an effective strategy which could lead to lowering the operating temperature to room temperature and significantly improving the sensitivity as well as the detection limit to a sub-ppm level, for meeting the requirement of advanced gas sensors for the next generation.
Inferring S-system Models of Genetic Networks from a Time-series Real Data Set of Gene Expression Profiles
(2008)
Huang, Hui-Ling
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Chen, Kuan-Wei
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Ho, Shinn-Jang
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Ho, Shinn-Ying
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生物科技學系
It is desirable to infer cellular dynamic regulation networks from gene expression profiles to discover more delicate and substantial functions in molecular biology, biochemistry, bioengineering, and pharmaceutics. The S-system model is suitable to characterize biochemical network systems and capable of analyzing the regulatory system dynamics. To cope with the problem "multiplicity of solutions", a sufficient amount of data sets of time-series gene expression profiles were often used. An efficient newly-developed method iTEA was proposed to effectively obtain S-system models from a large number (e.g., 15) of simulated data sets with/without noise. In this study, we propose an extended optimization method (named iTEAP) based on iTEA to infer the S-system models of genetic networks from a time-series real data set of gene expression profiles (using SOS DNA microarray data in E. coli as an example). The algorithm iTEAP generated additionally multiple data sets of gene expression profiles by perturbing the given data set. The results reveal that 1) iTEAP can obtain S-system models with high-quality profiles to best fit the observed profiles; 2) the performance of using multiple data sets is better than that of using a single data set in terms of solution quality, and 3) the effectiveness of iTEAP using a single data set is close to that of iTEA using two real data sets.
NiO functionalized Co3O4 hetero-nanocomposites with a novel apple-like architecture for CO gas sensing applications
(2019-11-15)
Chen, Kuan-Wei
;
Tsai, Ju-Heng
;
Chen, Chun-Hua
;
材料科學與工程學系
;
Department of Materials Science and Engineering
An innovative NiO functionalized Co3O4 hetero-nanocomposite exhibiting an unusual apple-like architecture has been successfully fabricated via a facile two-step chemical route for CO gas sensing applications. The unique mimetic morphology constructed by spike-like NiO nanobundles with sharp tips planted on the surface of the preformed extremely porous Co3O4 nanospheres not only creates specific structural advantages but, more importantly, induces chemical activation required for gas sensing. Higher sensitivity and lower operating temperature are thus obtained for the present NiO-Co3O4 hetero-nanocomposite in comparison with those for the bare Co3O4 nanospheres and also for most reported intrinsic or heterogeneous Co3O4 nano-oxides. (C) 2019 Elsevier B.V. All rights reserved.
The kinetics in mathematical models on segmentation clock genes in zebrafish
(2018-01-01)
Chen, Kuan-Wei
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Liao, Kang-Ling
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Shih, Chih-Wen
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應用數學系
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Department of Applied Mathematics
Somitogenesis is the process for the development of somites in vertebrate embryos. This process is timely regulated by synchronous oscillatory expression of the segmentation clock genes. Mathematical models expressed by delay equations or ODEs have been proposed to depict the kinetics of these genes in interacting cells. Through mathematical analysis, we investigate the parameter regimes for synchronous oscillations and oscillation-arrested in an ODE model and a model with transcriptional and translational delays, both with Michaelis-Menten type degradations. Comparisons between these regimes for the two models are made. The delay model has larger capacity to accommodate synchronous oscillations. Based on the analysis and numerical computations extended from the analysis, we explore how the periods and amplitudes of the oscillations vary with the degradation rates, synthesis rates, and coupling strength. For typical parameter values, the period and amplitude increase as some synthesis rate or the coupling strength increases in the ODE model. Such variational properties of oscillations depend also on the magnitudes of time delays in delay model. We also illustrate the difference between the dynamics in systems modeled with linear degradation and the ones in systems with Michaelis-Menten type reactions for the degradation. The chief concerns are the connections between the dynamics in these models and the mechanism for the segmentation clocks, and the pertinence of mathematical modeling on somitogenesis in zebrafish.