Browsing by Author "Huang, Yi-Chia"

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A facile dedoping approach for effectively tuning thermoelectricity and acidity of PEDOT:PSS films
(2014-03-01)
Tsai, Tsung-Che
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Chang, Hsiu-Cheng
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Chen, Chun-Hua
;
Huang, Yi-Chia
;
Whang, Wha-Tzong
A facile approach namely controlling the pH level of 5 wt% dimethyl sulfoxide (DMSO) doped poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution with sodium hydroxide (NaOH) was utilized for the first time in successfully optimizing the thermoelectric conversion efficiency of PEDOT:PSS films. The largely varied Seebeck coefficients and electrical conductivities of the pH controlled PEDOT:PSS films which could thus construct a beneficial curve for locating the optimized power factor are clearly shown from the significant changes of the carrier concentration via the dedoping of PEDOT. The correlation between pH value and carrier concentration as well as the power factor is experimentally found with numerical description covering a full pH range. The applied technique and the resulting optimized thermoelectric properties and possible bio-compatibility not only provide a fundamental understanding of the thermoelectric conducting polymers but widely disclose a variety of potential applications in the future. (C) 2014 Elsevier B. V. All rights reserved.
A Facile Surface Treatment Utilizing Binary Mixtures of Ammonium Salts and Polar Solvents for Multiply Enhancing Thermoelectric PEDOT: PSS Films
(2014-12-01)
Tsai, Tsung-Che
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Chen, Tsung-Han
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Chang, Hsiu-Cheng
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Chen, Chun-Hua
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Huang, Yi-Chia
A Novel Smart Assistance System for Blood Vessel Approaching: A Technical Report Based on Oximetry
(2020-04-01)
Lee, Chien-Ching
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Chuang, Chia-Chun
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Lai, Bo-Cheng
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Huang, Yi-Chia
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Chen, Jen-Yin
In clinical practice, the catheter has to be placed at an accurate position during anesthesia administration. However, effectively guiding the catheter to the accurate position in deeper tissues can be difficult for an inexperienced practitioner. We aimed to address the current issues associated with catheter placement using a novel smart assistance system for blood vessel catheter placement. We used a hollow introducer needle embedded with dual wavelength (690 and 850 nm) optical fibers to advance the tip into the subclavian vessels in anesthetized piglets. The results showed average optical density changes, and the difference between the absorption spectra and hemoglobin concentrations of different tissue components effectively identified different tissues (p < 0.05). The radial basis function neural network (RBFNN) technique was applied to distinguish tissue components (the F-measure value and accuracy were 93.02% and 94%, respectively). Finally, animal experiments were designed to validate the performance of the proposed system. Using this system based on oximetry, we easily navigated the needle tip to the target vessel. Based on the experimental results, the proposed system could effectively distinguish different tissue layers of the animals.
An in situ fabrication process for highly electrical conductive polyimide/MWCNT composite films using 2,6-diaminoanthraquinone
(2013-10-18)
Huang, Yi-Chia
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Lin, June-Hua
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Tseng, I-Hsiang
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Lo, An-Ya
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Lo, Teng-Yuan
We present a valuable in situ fabrication process for synthesizing high electrical conductive polyimide/multiwalled carbon nanotube (PI/MWCNT) composite films. The success of this process was achieved the addition of 2,6-diaminoanthraquinone (DAAQ). The DAAQ is not only an excellent dispersion agent to stably disperse pristine MWCNTs in solvent but also a monomer to directly synthesize PI. The strong interaction between DAAQ with MWCNT was verified by FTIR, UV-Vis, Raman, and fluorescence spectra. The highest value of electrical conductivity of 55.6 S/cm are achieved by the PI composite containing 40 wt.% of MWCNT. Moreover, the electrical conductivity of this film further enhanced to 106 S/cm after the thermal compression process. The MWCNT content at the percolation threshold of conductivity is 0.50 wt.% (or 0.32 vol.%) and the critical exponent is equal to 2.52. The developed in situ fabrication process through DAAQ-derived molecules can also be applied to synthesize other polymers requiring diamine structure. (C) 2013 Published by Elsevier Ltd.
Anti-corrosion characteristics of polyimide/h-boron nitride composite films with different polymer configurations
(2014-12-15)
Huang, Yi-Chia
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Lo, Teng-Yuan
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Chao, Cheun-Guang
;
Whang, Wha-Tzong
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材料科學與工程學系
Anti-corrosive polyimide/hexagonal boron nitride (PI/h-EN) composite films were prepared with different monomers to offer different polymer configurations: rigid and soft. In PI/h-BN composite films, different configurations of polymers show different crystallinity trends of the polymer matrix. In our study, the degree of crystallinity in rigid polymer decreases with the EN content; in flexible polymers it is independent of the BN content. It is worth noting that BN in different PI matrices can effectively enhance the protection of steel from corrosion. With a flexible PI matrix, the PI/h-BN coating exhibited better resistance to water vapor and better anti-corrosion. Only 5 wt.% of h-BN in the composite is enough to offer high anti-corrosion, a positive corrosion voltage. (C) 2014 Elsevier B.V. All rights reserved.
Design of Novel Field Programmable Gate Array-Based Hearing Aid
(2019-01-01)
Lin, Bor-Shing
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Yang, Po-Yu
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Liu, Ching-Feng
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Huang, Yi-Chia
;
Liu, Chengyu
Hearing loss is one of the most common chronic diseases. For people with hearing loss, communicating with other people, particularly in an environment with considerable background noise, is difficult. Recently, several hearing aids have been developed to improve speech comprehension in a noisy environment. The use of an adaptive beamformer is one of the alternative methods for improving speech intelligibility. However, the adaptive beamformer requires the location of the desired speaker to estimate the time differences of arrival (TDOAs) of speech sources to numerous spatially separated sensors in acoustics. In general, the technique of steered response power source localization was used to estimate the TDOA; however, this technique was easily affected by environmental reverberation. To overcome the aforementioned concern, a novel hearing aid is proposed in this paper. By using an image processing technology, the location of the desired speaker could be manually selected to provide precise information on the TDOA. Moreover, adaptive signal enhancements were implemented in a field-programmable gate array to enhance the speech of interest in real time. The experimental results indicate that the proposed system could improve speech intelligibility in various noisy environments. Therefore, the proposed system may be employed to improve the daily lives of people with hearing the loss in the future.
Effect of phosphate surface pretreatment on corrosion resistance and adhesion of PI coating on Mg-5 wt.% Sn alloy
(2015-06-18)
Lee, Hsiao-Chien
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Huang, Yi-Chia
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Liu, Tzeng-Feng
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Whang, Wha-Tzong
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Chao, Chuen-Guang
In this study, phosphate surface pretreatment (PSPT) and poly[pyromellitic dianhydride-co-4,4MODIFIER LETTER PRIME-oxydianiline] polyimide (PMDA-ODA PI) coating were used to provide corrosion protection for Mg-5 wt.% Sn alloy. PSPT enhanced the adhesion of PI coating by mechanical interlocking and chemical anchoring. Surface roughness was increased and provided stronger mechanical interlocking. Phosphates were formed on the alloy surface to act as anchor groups. Energy dispersive X-rayspectrometer and X-ray photoelectron spectroscopy results indicated that bonds formed between anchor groups and PI coating. The bonds provided chemical anchoring and enhanced the adhesion of PI coating. The increase of corrosion resistance of PI coating on Mg-5 wt.% Sn alloy (E-corr = -0.86V/SCE, [GRAPHICS] mu A cm(-2) and corrosion rate far less than [GRAPHICS] showed the bonds were stable enough to stand the attack of electrolyte and inhibit the electrochemical reaction at the interface.
Electrospinning of magnesium-ion linked binder-less PEDOT:PSS nanofibers for sensing organic gases
(2015-09-01)
Huang, Yi-Chia
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Lo, Teng-Yuan
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Chen, Chun-Hua
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Wu, Kai-Hung
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Lin, Chien-Min
Controlled and continuous electrospinning of approximately pure poly(3,4-ethylenedioxythiophene): poly( styrenesulfonate) (PEDOT:PSS) nanofibers has been successfully realized for the first time by alternating the great amount of conventional carrier polymers with only slight doping of magnesium nitrate which acts as a polymer cross-linker for significantly enhancing the entanglement of PEDOT:PSS. In contrast to the less response of the bulky PEDOT:PSS film, the electrospun PEDOT:PSS nanofibers exhibit remarkably high sensitivities and responding speeds in respectively sensing gas molecules of dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and propylene carbonate (PC). (C) 2015 Elsevier B.V. All rights reserved.
Enhancement of adhesion between copper foil and polyimide film containing thermally decomposable polystyrene particles
(2012-11-25)
Tsai, Mei-Hui
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Huang, Yi-Chia
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Tseng, I-Hsiang
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Yu, Hsin-Pei
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Lin, Yin-Kai
A facile method was developed to synthesize porous polyimide (PI) films with enhanced adhesion to Cu foil. Various amounts (0.14 wt %) of polystyrene (PS) spheres with the diameter of 250 nm were mixed with the PI precursor synthesized from pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline in N,N'-dimethylacetamide. PS was decomposed during thermal imidization process to create the porous PI structure. The increase in surface area and surface roughness was observed from the obtained porous PI films and was a function of the PS content up to 4 wt %. A significant improvement in the adhesion strength between porous PI film and Cu foil, which was determined by 90 degrees peel test, was achieved. The adhesion strength of PI containing 4 wt % PS to Cu was 1.53 kgf/cm compared with pure PI of 1.08 kgf/cm. Meanwhile, the synthesized porous PI films exhibit sufficient mechanical strength and thermal stability for practical applications. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of superhydrophobic polyimide films modified with organosilicasol as effective anticorrosion coatings
(2014-11-15)
Lo, Teng-Yuan
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Huang, Yi-Chia
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Hsiao, Yi-Nan
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Chao, Chuen-Guang
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Whang, Wha-Tzong
In this study we prepared superhydrophobic polyimide (PI) hybrid coatings for anticorrosion application by adjusting their surface roughness and surface composition through spray-coating with silylated perfluoroalkylsilane-modified organosilicasol (silylated fluoro-organosilicasol), which increased the surface hydrophobicity. After silylation with 1,1,1,3,3,3-hexamethyldisilazane (HMDS), the silylated fluoro-organosilicasol further transformed the PI surface into a superhydrophobic state with a static water contact angle of greater than 1600 and a low hysteresis of 10 degrees. We examined the mechanism behind the enhancement in superhydrophobicity through analyses of the surface topology and chemical composition of the films, using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electron spectroscopy for chemical analysis (ESCA). These analyses suggested that both surface roughness and silylation of the fluoro-organosilicasol making more CF2 groups on the outmost surface rendered the surface hydrophobicity. The anticorrosion properties of these superhydrophobic coatings were also examined through Tafel measurement. These PI hybrid coatings demonstrated lower corrosion current density and nobler corrosion potential and higher polarization resistance. The enhancement in anticorrosion performance was believed to be contributed from the superhydrophobicity and dual barrier protection from the fully-covered fluoro-organosilicasol, insulating the metal from corrosive species in the medium. This superhydrophobic coating technique with good stability guaranteed better corrosion protection and also has great potential for application to other polymeric films. (C) 2014 Elsevier B.V. All rights reserved.
Significant improvement in the thermoelectric properties of zwitterionic polysquaraine composite films
(2013-09-16)
Ho, Mei-Chan
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Chao, Ching-Hsun
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Lo, An-Ya
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Chen, Chun-Hua
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Wu, Ren-Jye
In this study, the polysquaraine SQI(0.1), a zwitterionic pi-conjugated polymer, was adopted as the matrix for the preparation of flexible and freestanding films; the low band gap of this semiconducting polymer made it a natural choice for use as a thermoelectric (TE) polymer. To enhance their TE applications, both single-walled carbon nanotubes (SWNTs) and mesoporous carbon (i.e., CMK-3) were integrated into the SQI(0.1)-based films and the effects of doping with iodine were also investigated. Using scanning electron microscopy, the variations in morphology of these SQI(0.1)-based films were examined. Raman spectroscopy was used to study the pi-pi interactions between iodine and the carbon materials (Le., SWNT, CMK-3); X-ray diffraction and Raman spectroscopy to investigate the intercalation of the doped iodine in the composite films; and X-ray photoelectron spectroscopy to determine the valence state of the doped iodine. The TE properties of these materials were characterized in terms of the electrical conductivity (sigma), thermal conductivity (kappa), and Seebeck coefficient (S). The TE properties of the iodine-doped composite film prepared from SWNTs, CMK-3, and SQI(0.1) included a notable value of ZT (Figure of Merit) of 4.563 x 10(-3), which was 143% of that of the corresponding iodine-doped SQI(0.1) film. (c) 2013 Elsevier B.V. All rights reserved.
The Microwave Signal Linewidth in a Monolithically Integrated Two-Section DFB Laser under Controllable Feedback
(2016)
Dong, Yao-Zhong
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Hsiao, Fu-Chun
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Huang, Yi-Chia
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Lin, Chien-Chung
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光電系統研究所
A controllable optical feedback system was set up to investigate the linewidth of the RF signals generated by a two-section DFB laser. A very narrow line (its width less than 100 kHz) can be detected when both sections are under the influence of optical feedback.
Thermal and mechanical properties of polyimide/nano-silica hybrid films
(2011-05-31)
Tsai, Mei-Hui
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Huang, Yi-Chia
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Tseng, I-Hsiang
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Yu, Hsin-Pei
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Lin, Yin-Kai
A novel route to synthesize polyimide (PI)/silica hybrid films with improved thermal and mechanical properties was developed. Low-molecular-weight poly(amic acid) (PAA), which is the precursor of PI, was successfully synthesized by controlling the molar ratio of monomers, [4,4'-(4,4'-isopropylidenediphenoxy) bis(phthalic anhydride)] (IDPA) and 2,2'-bis(4-(4-aminophenoxy)phenyl)propane (BAPP). The PM with its low-molecule-weight feature showed good compatibility with silica-sol and dispersed well within the network of silica-sol. Silica nanoparticles with an average size of 20 nm were obtained without adding coupling agents and dispersed homogenously within the resulting PI/silica hybrid films due to the hydrogen bonding between Si-OH groups and C=O in imide rings of polyimide. The improvement in the storage modulus and the coefficient of thermal expansion (CTE) by hybrid films was revealed. With the presence of 50 wt.% silica in hybrid films, the storage modulus was 5857 MPa and the CTE was 18.1 ppm/degrees C. compared with 1620 MPa and 76.5 ppm/degrees C for pure PI. Most importantly, the transmission at 550 nm was 81.4% for the hybrid film with 50 wt.% silica, which is close to 87.5% for pure PI. The CTE of the hybrid film dropped to the level comparable with that of copper without sacrificing its transparency, which was associated with the well-dispersed silica nanoparticles and the semi-interpenetrating polymer network (semi-IPN) structure within the PI matrix. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
Zr-MOF/Polyaniline Composite Films with Exceptional Seebeck Coefficient for Thermoelectric Material Applications
(2019-01-23)
Lin, Chih-Chien
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Huang, Yi-Chia
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Usman, Muhammad
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Chao, Wen-Hsuan
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Lin, Wei-Keng
Controlling the polymerization of aniline in the presence of zirconium-based metal-organic frameworks (Zr-MOFs) using polystyrene sulfonic acid as a dopant resulted in the formation of a new type of freestanding thermoelectric composite film. Polyaniline chains interpenetrate into the Zr-MOFs to enhance the crystallinity of polyaniline, resulting in an improved degree of electrical conductivity. In addition, the inherent porosity of the Zr-MOFs functions to suppress the increase in thermal conductivity, thus dramatically promoting a negative Seebeck coefficient. When 20 wt % Zr-MOF was used, a power factor of up to 664 mu W/(m K-2) was obtained, which was accompanied by a surprisingly large, negative Seebeck coefficient. The new class of MOF-based composites offers a new direction for developing new types of efficient thermoelectric materials.