Browsing by Author "Yang, Jung-Yen"

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Hydrothermally Roughened Surface-Enhanced Raman Scattering-Active Substrates with Low Background Signals for Chemical Sensing Application
(2011-03-01)
Yang, Jung-Yen
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Cheng, Hui-Wen
;
Chen, Yu
;
Li, Yiming
;
Lin, Chi-Hung
A low-cost, environment friendly and easily fabricated SERS-active substrate with low background signals has been developed by hydrothermal treatment of titanium thin films deposited on silicon substrate. Results from the experimental study revealed that Rhodamine 6G can be well resolved using gold-coated hydrothermally roughened TiO(2) substrates. The effect of surface enhancement by the hydrothermally roughened substrates enables rapid identification of Rhodamine 6G, and the enhancement capability is controllable by tuning the surface roughness of the substrates through varying treatment duration. The hydrothermally treated TiO(2) substrates also exhibit tunable wettability like that of the untreated ones.
Investigation of Raman enhancement in hydrothermally roughened SERS-active substrates
(2011-01-01)
Cheng, Hui-Wen
;
Li, Yiming
;
Yang, Jung-Yen
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this work we study surface enhanced Raman spectroscopy (SERS) active substrates for the detection of Rhodamine 6G To examine the electromagnetic enhancement we apply the finite-difference time-domain (FDTD) algorithm to analyze the structures by solving a set of coupled Maxwell's equations (Ampere s Law and Faraday s Law) in differential form The field enhancements are thus investigated in the visible regime with the wavelength of 633 nm In our experimental measurement the surface enhanced Raman scattering signals from the surface of substrates with 12-hour treatment and without treatment are performed and compared Through the three-dimensional (3D) FDTD calculation we find that the hydrothermally 12-hour treated samples possess significantly vertical variations of surface and thus have relatively larger field enhancement than those without treated Consequently it implies a strong positive effect on the surface enhancement which is consistent with the measured intensity (C) 2010 Elsevier B V All rights reserved
Minimal Antizyme Peptide Fully Functioning in the Binding and Inhibition of Ornithine Decarboxylase and Antizyme Inhibitor
(2011-09-09)
Hsieh, Ju-Yi
;
Yang, Jung-Yen
;
Lin, Chih-Li
;
Liu, Guang-Yaw
;
Hung, Hui-Chih
Antizyme (AZ) is a protein with 228 amino acid residues that regulates ornithine decarboxylase (ODC) by binding to ODC and dissociating its homodimer, thus inhibiting its enzyme activity. Antizyme inhibitor (AZI) is homologous to ODC, but has a higher affinity than ODC for AZ. In this study, we quantified the biomolecular interactions between AZ and ODC as well as AZ and AZI to identify functional AZ peptides that could bind to ODC and AZI and inhibit their function as efficiently as the full-length AZ protein. For these AZ peptides, the inhibitory ability of AZ_95-228 was similar to that of AZ_WT. Furthermore, AZ_95-176 displayed an inhibition (IC(50): 0.20 mu M) similar to that of AZ-95-228 (IC(50): 0.16 mM), even though a large segment spanning residues 177-228 was deleted. However, further deletion of AZ_95-176 from either the N-terminus or the C-terminus decreased its ability to inhibit ODC. The AZ_100-176 and AZ_95-169 peptides displayed a noteworthy decrease in ability to inhibit ODC, with IC(50) values of 0.43 and 0.37 mM, respectively. The AZ_95-228, AZ_100-228 and AZ_95-176 peptides had IC(50) values comparable to that of AZ_WT and formed AZ-ODC complexes with K(d,AZ-ODC) values of 1.5, 5.3 and 5.6 mu M, respectively. Importantly, our data also indicate that AZI can rescue AZ peptide-inhibited ODC enzyme activity and that it can bind to AZ peptides with a higher affinity than ODC. Together, these data suggest that these truncated AZ proteins retain their AZI-binding ability. Thus, we suggest that AZ_ 95-176 is the minimal AZ peptide that is fully functioning in the binding of ODC and AZI and inhibition of their function.
One-step fabrication of surface-relief diffusers by stress-induced undulations on elastomer
(2009-09-01)
Wang, Jui-Hao
;
Chen, Chia-Fu
;
Ho, Jeng-Rong
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Shih, Teng-Kai
;
Chen, Chien-Chung
In this study, we demonstrated that microscale surface undulations induced by acid treatment could serve as the surface relief on diffusers coated with a layer of PDMS polymer. Since the orientation of undulations was found to be always disordered, these undulations would scatter light uniformly. The periodicity of the undulations could be adjusted by the control of duration of the dipping of the elastomer into H(2)SO(4)/HNO(3) solutions and by the volume ratio of H(2)SO(4)/HNO(3) the solution, resulting in the modulation of diffusing ability of diffusers. The optical properties, transmittance, and light diffusivity, were characterised. This proposed approach offers potential for mass production of surface-relief diffusers. In addition, the proposed method allows the creation of undulations on arbitrary substrates. (C) 2008 Elsevier Ltd. All rights reserved.
Pentacene-based thin-film transistors with multiwalled carbon nanotube source and drain electrodes
(2007-08-20)
Chang, Chia-Hao
;
Chien, Chao-Hsin
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Yang, Jung-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
In this letter, the authors propose a practical and reliable approach-using deposited multiwalled carbon nanotubes (MWCNTs) as source and drain electrodes-for reducing the contact resistance (R-c) in pentacene-based bottom-contact thin-film transistors. The value of R-c of the devices was closely linked to the resultant length of the deposited MWCNTs; the lowest value was 3x10(8) Omega mu m. The largest saturation mobility was 0.14 cm(2)/V s; this value reached up to three times higher when the threshold voltage was determined using the maximum transconductance (G(m,max)) extrapolation method, rather than the constant current method. The on/off ratio was more than 10(6). (C) 2007 American Institute of Physics.
Shape Effect of Surface-Enhanced Raman Scattering-Active-Substrate-Based Nanoparticles on Local Electric Field for Biochemical Sensing Application
(2017-02-01)
Lee, En-Tzu
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Cheng, Hui-Wen
;
Yang, Jung-Yen
;
Li, Yiming
;
電機工程學系
The metal nanoparticles exhibit different degrees of localized surface plasmon resonance which depends on different type nano-sized structures. In this work, in experiment, Au/TiO2/Ti/Si SERS-active substrate with spherical shape nanoparticles is fabricated by using a hydrothermal treatment process and applied to detect Rhodamine 6G sample. Based on experimental observation, a threedimensional finite-difference time-domain simulation is utilized to explore the local field distributions. We examine the effect of surface roughness and shape of Au nanoparticles on the enhancement magnitude of local electric field of SERS-active substrates. Besides, different shapes of nanoparticles, nanocages and Au/Ag alloy nanoparticles are also modeled and discussed. The engineering findings of this study indicate that the substrate with roughened surface may exhibit large electric field enhancement; in particular, for the cubic shape of nanoparticles. The electric field enhancement of spherical and cubic nanoparticles could be further enlarged by Au/Ag alloy and Au nanocage structures. The results may benefit the design and fabrication of nanoparticles for various biochemical sensing applications.