• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.196.2-196.2
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• 2014

Nanostructuring the electrode surface is an emerging technology to improve the performance of supercapacitors since it can facilitate charge transfer, ion diffusion and electron propagation during electrochemical process. Fabrication of the electrode consisting of two or more materials together has also been focused on since it can provide synergetic effect such as broader working potential range and enhanced capacitance. In this work, we have used polyaniline (PANi) and manganese oxide (MnO2) as electrode materials. PANi is one of the promising electrode materials due to its high electrochemical activity, high doping level and stability. MnO2 is also widely studied material for supercapacitors since it is relatively cheap and environmentally friendly. Firstly, we synthesized polystyrene nanospheres on MnO2 nanoparticles. MnO2-incorporated PANi hollow nanospheres were then fabricated by polymerizing aniline monomers on these PS nanospheres and dissolving the inner PS spheres. The surface morphology, electronic absorption and electrical conductivity of the electrode were analyzed using field-emission scanning electron microscope (FE-SEM), UV-visible spectrometer, and sheet resistivity meter, respectively. The electrochemical properties such as capacitance of the supercapacitors were also estimated using cyclic voltammetry.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.278.2-278.2
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• 2014

We have investigated the highly flexible and transparent Si-doped $In_2O_3$(ISO)/Ag/ISO multilayer grown on polyethylene terephthalate (PET) substrates using a roll-to-roll sputtering system. The electrical and optical properties of ISO/Ag/ISO multilayer electrodes depended on the insertion of a nano-size Ag layer. Due to the high conductivity of a nano-size Ag layer, the optimized ISO/Ag/ISO multilayer electrodes showed the lowest resistivity of $3.679{\times}10^{-5}Ohm-cm$, even though the ISO/Ag/ISO multilayer electrodes was sputtered at room temperature. Furthermore, the ISO/Ag/ISO multilayer electrodes exhibited a high transmittance of 86.33%, because of the anti-reflection effect, comparable to Sn-doped $In_2O_3$ (ITO) electrodes. In addition, the ISO/Ag/ISO multilayer electrodes had a very smooth surface morphology without surface defects and showed good flexibility. The flexible OSCs fabricated on ISO(30nm)/Ag(8nm)/ISO(30nm) multilayer electrode showed a power conversion efficiency of 3.272%. This result indicates that the ISO/Ag/ISO multilayer is a promising transparent conducting electrode for flexible OSCs.

• 한국재료학회지
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• 제17권7호
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• pp.376-381
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• 2007

Fluorine-doped tin oxide (FTO) thin film was coated on aluminosilicate glass at $450^{\circ}C$ by spray pyrolysis method. In the range of 0-2.7 molar ratio of F/Sn, the variations of electrical conductivity and visible light transmission were investigated. At the F/Sn ratio of 1.765, the film showed the lowest electrical resistivity value of $3.0{\times}10^{-4}{\Omega}\;cm$, the highest carrier concentration of $2.404{\times}10^{21}/cm^3$, and about $8\;cm^2/V{\cdot}sec$ of electronic mobility. The FTO film showed a preferred orientation of (200) plane parallel to the substrate. X-ray photoelectron spectroscopy analysis results indicated that the contents of $Sn^{4+}-O$ bonding are the highest at 1.765 of F/Sn molar ratio.

• 한국표면공학회지
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• 제45권1호
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• pp.1-7
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• 2012

Multi-walled carbon nanotube (MWCNT) aluminum composite powders were deposited to form coatings using a high velocity oxygen fuel (HVOF) spraying process. High thermal energy and contact with atmospheric oxygen were supplied as the MWCNT aluminum composite particles were exposed to a gas flow field at high temperature (${\sim}3.0{\times}10^3$ K) during HVOF spraying. As a result, the particles underwent full or partial melting and rapid solidification due to the high thermal energy, and the exposure to oxygen induced the interfacial reaction of MWCNTs within the particle. The electrical and mechanical properties of MWCNT aluminum composite coatings were evaluated based on microstructure analysis. Electrical resistivity, elastic modulus, and micro-hardness, of the MWCNT aluminum composite coatings were higher than those of pure aluminum coating. The contribution of MWCNTs to the aluminum matrix can be attributed to their high electrical conductivity, dispersion hardening and anchoring effects. The relationship among the properties and the interaction of the MWCNTs with the aluminum matrix is discussed.

• 폴리머
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• 제25권2호
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• pp.293-301
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• 2001

새로운 복합재료 제조 기술인 electron-ion technology (EIT)를 이용하여 전도성 탄소섬유/고밀도 폴리에틸렌 (CF/HDPE) 복합필름을 제조하고 탄소섬유 에폭시 sizing이 제조된 필름의 체적비저항과 인장강도 그리고 계면 특성에 미치는 영향에 대하여 연구하였다. 에폭시 sizing은 tunneling 효과를 좋게 해서 복합재료 필름의 전도성을 향상시키는 반면, 극성인 에폭시 sizing은 무극성인 폴리에틸렌과의 친화성이 없어서 탄소섬유와 폴리에틸렌간의 계면결합력을 감소시키므로 에폭시 sized 탄소섬유(CF(S))는 unsized 탄소섬유(CF(U))에 비하여 필름의 체적비저항과 인장강도를 감소시켰다. 에폭시 sizing은 탄소섬유의 nucleating efficiency를 떨어뜨려서 CF(S)/HDPE 필름이 CF(U)/HDPE 필름보다 불규칙적이고 덜 발달된 transcrystalline layer를 형성함을 관찰할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.138-138
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• 2008

In this study, effect of thickness on structural, electrical and optical properties of B doped ZnO:Al (AZOB) films was investigated. AZOB films were deposited on PC substrates by DC magnetron sputtering. The thickness range of films were from 300 nm to 800 nm to identified as increasing thickness, stress between substrate and AZOB film. The. average transmittance of the films was over 80 % until 500 nm. Then a resistivity of $1.58\times10^{-3}\Omega$-cm was obtained. We presented that a AZOB film of 500 nm was optimization to obtain a high transmittance and conductivity.

• Computers and Concrete
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• 제7권1호
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• pp.53-62
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• 2010

Dredged silt from reservoirs in southern Taiwan was sintered to make lightweight aggregates (LWA), which were then used to produce high-performance lightweight aggregate concrete (HPLWC). The HPLWC was manufactured using different amounts of mixing water (140, 150, and 160 $kg/m^3$) and LWA of different particle densities (700, 1100, and 1500 $kg/m^3$) at different W/b ratios (0.28, 0.32, and 0.4). Results show that the lightweight aggregates of dredged silt taken in southern Taiwan perform better than the general lightweight aggregates. In addition, the HPLWC possessed high workability with a slump of 230-270 mm, and a slump flow of 450-610 mm, high compressive strength of over 40 MPa after 28 days of curing, good strength efficiency of cement exceeding $0.1MPa/kg/m^3$, low thermal conductivity of 0.4-0.8 $kcal/mh^{\circ}C$, shrinkage of less than $4.8{\times}10^{-4}$, and high electrical resistivity of above 40 $k{\Omega}-cm$. The above findings prove that HPLWC made from dredged silt can help enhance durability of concrete and provide and an ecological alternative use of dredged silt.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 3차
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• pp.37-46
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• 2010

Marine clays are soft soil deposits having complicated mineralogy and formation characteristics. Thus, characterization of its geotechnical behavior has been a main issue for geotechnical engineers. Nowadays, the importance and applications of geophysical exploration on marine clays are increasing significantly according to the accuracy, efficiency, and reliability of geophysical survey technology. For marine clays, seismic survey is effective for density and elasticity characterization, while electro-magnetic wave provides the information about the fluid conductivity phenomena inside soil. For practical applications, elastic wave technology can evaluate the consolidation state of natural marine clay layers and estimate important geotechnical engineering parameters of artificially reclaimed marine deposits. Electrical resistivity can provide geophysical characteristics such as particle cementation, pore geometry shape, and pore material phase condition. Furthermore, nondestructive geophysical monitoring is applicable for risk management and efficiency enhancement during natural methane gas extraction from gas hydrate-bearing sediments.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.760-763
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• 2004

We studied the nematic liquid crystaL(NLC) aligning capabilities using the new alignment material of a nitrogenated diamond-like carbon(NDLC) thin film. The NDLC thin film exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) thin films. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. A high pretilt angle of about 9.9$^{\circ}$ by ion beam(IB) exposure on the NDLC thin film surface was measured. A good LC alignment is achieved by the IB alignment method on the NDLC thin films surface at annealing temperature of 200 $^{\circ}C$. The alignment defect of the NLC was observed above annealing temperature of 250 $^{\circ}C$. Consequently, the high pretilt angle and the good LC alignment by the IB alignment method on the NDLC thin film surface can be achieved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 제6회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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• pp.23-26
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• 2004

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a Carbon Nitride (NDLC) thin film. NDLC thin film exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) thin films. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. A high pretilt angle of about $9.9^{\circ}$ by ion beam (IB) exposure on the NDLC thin film surface was measured. A good LC alignment is achieved by the IB alignment method on the NDLC thin film surface at annealing temperature of $200^{\circ}C$. The alignment defect of the NLC was observed above annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good LC alignment by the IB alignment method on the NDLC thin film surface can be achieved.