• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1277-1278
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• 2008

Pentacene 박막 트랜지스터의 소스/드레인 전극을 폴리머인 Poly(3,4-ethylene dioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)를 사용하여 잉크젯 프린팅 방법으로 제작하였다. 펜타신 박막 트랜지스터는 열 증착법을 사용하여 폴리며 기판위에 100nm의 두께로 증착하였다. 게이트 절연막은 $SiO_2$ 위에 Polymethly Methacrylate (PMMA)를 증착시킨 double layer를 사용하였다. PMMA 위에 증착시킨 pentacene 결정립이 $SiO_2$ 위에 증착한 pentacene 결정립 보다 크게 성장하였고, double layer의 절연막을 씀으로 인해 게이트 누설 전류가 감소함을 보였다. Pentacene 증착 온도에 따른 결정립 크기를 비교하여 가장 적절한 온도를 찾았다. 프린팅 방법을 사용하여 만든 박막 트랜지스터는 전계효과 이동도가 ${\mu}_{FET}=0.023cm^2/Vs$ 이고, 문턱이전 기울기 S.S=0.49V/dec, 문턱전압 $V_{th}=-18V$, $I_{on}/I_{off}$ 전류비 >$10^3$의 전기적 특성을 보였다.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.119-125
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• 2011

In this paper, we have studied about minimizing the Energy Storage System (ESS) capacity for mitigating the fluctuation of Wind Turbine Generation System (WTGS) by using Electric Double Layer Capacitor (EDLC) and Battery Energy Storage System (BESS). In this case, they have some different characteristics: The EDLC has the ability of generating the output power at high frequency. Thus, it is able to reduce the fluctuation of WTGS in spite of high cost. The BESS, by using Li-Ion battery, takes the advantage of high energy density, however it is limited to use at low frequency response. To verify the effectiveness of the proposed method, simulations are carried out with the actual data of 2MW WTGS in case of worst fluctuation of WTGS is happened. By comparing simulation results, this method shows the excellent performance. Therefore, it is very useful for understanding and minimizing the ESS capacity for mitigating the fluctuation of WTGS.

• Korea-Australia Rheology Journal
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• v.15 no.2
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• pp.83-90
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• 2003

In cases of the microfluidic channel, the electrokinetic influence on the transport behavior can be found. The externally applied body force originated from the electrostatic interaction between the nonlinear Poisson-Boltzmann field and the flow-induced electrical field is applied in the equation of motion. The electrostatic potential profile is computed a priori by applying the finite difference scheme, and an analytical solution to the Navier-Stokes equation of motion for slit-like microchannel is obtained via the Green's function. An explicit analytical expression for the induced electrokinetic potential is derived as functions of relevant physicochemical parameters. The effects of the electric double layer, the zeta potential of the solid surface, and the charge condition of the channel wall on the velocity profile as well as the electroviscous behavior are examined. With increases in either electric double layer or zeta potential, the average fluid velocity in the channel of same charge is entirely reduced, whereas the electroviscous effect becomes stronger. We observed an opposite behavior in the channel of opposite charge, where the attractive electrostatic interactions are presented.

• Korean Journal of Materials Research
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• v.31 no.5
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• pp.272-277
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• 2021

Owing to its low cost, easy fabrication process, and good ionic properties, aqueous supercapacitors are under strong consideration as next-generation energy storage devices. However, the limitation of the current collector is its poor electrochemical stability, leading to low energy storage performance. Therefore, a reasonable design of the current collector and the acidic electrolyte is a necessary, as well as interfacial engineering to enhance the electrochemical performance. In the present study, graphite foil, with excellent electrochemical stability and good electrical properties, is suggested as a current collector of aqueous supercapacitors. This strategy results in excellent electrochemical performance, including a high specific capacitance of 215 F g^-1 at a current density of 0.1 A g^-1, a superior high-rate performance (104 F g^-1 at a current density of 20.0 A g^-1), and a remarkable cycling stability of 98 % at a current density of 10.0 A g^-1 after 9,000 cycles. The superior energy storage performance is mainly ascribed to the improved ionic diffusion ability during cycling.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.9
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• pp.589-593
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• 2014

AlNO multi-layer thin films on aluminum substrates were prepared by DC reactive magnetron sputtering method. $Al_2O_3$/AlNO(LMVF)/AlNO(HMVF)/Al/substrate of 4 multi-layer has been prepared in an Ar and ($N_2+O_2$) gas mixture, and $Al_2O_3$ of top layer is anti-reflection layer on double AlNO(LMVF)/AlNO(HMVF) layers and Al metal of infrared reflection layer. In this study, the roughness and surface properties of AlNO thin films were estimated by field emission scanning electron microscopy(FE-SEM). The grain size of AlNO thin films increased with increasing sputtering power. The composition of thin films has been systematically investigated using electron probe microanalysis(EPMA). The optical properties with wavelength spectrum were recorded by UV-Vis-NIR spectrophotometry at a range of 200~1,500 nm. The absorptance of AlNO films shows the increasing trend with swelling ($N_2+O_2$) gas mixture in HMVF and LMVF deposition. The excellent optical performance showed above 98% of absorptance in visible wavelength region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.820-824
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• 2014

TiNOx multi-layer thin films on aluminum substrates were prepared by DC reactive magnetron sputtering method. 4 multi-layers of $TiO_2$/TiNOx(LMVF)/TiNOx(HMVF)/Ti/substrate have been prepared with ratio of Ar and ($N_2+O_2$) gas mixture. $TiO_2$ of top layer is anti-reflection layer on double TiNOx(LMVF)/TiNOx(HMVF) layers and Ti metal of infrared reflection layer. In this study, the crystallinity and surface properties of TiNOx thin films were estimated by X-ray diffraction(XRD) and field emission scanning electron microscopy(FE-SEM), respectively. The grain size of TiNOx thin films shows to increase with increasing sputtering power. The composition of thin films has been investigated using electron probe microanalysis(EPMA). The optical properties with wavelength spectrum were recorded by UV-Vis-NIR spectrophotometry at a range of 200~1,500 nm. The TiNOx multi-layer films show the excellent optical performance beyond 9% of reflectance in those ranges wavelength.

• 전기의세계
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• v.27 no.4
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• pp.52-59
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• 1978

This paper is prepaped, based upon its foundation of the design, first studying the rotor impedance of single and double layer cylindrical induction motor with solid iron rotor, and then inducing torque equation, from it. Classified were some design factors for this design from the result for above and there carried out the evidence of these design and theory after making experimental motors with solid iron rotors and examining torque characteristics.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.477-480
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• 2017

전기이중층 Capacitor는 대전력을 쉽게 충방전할 수 있는 전력저장장치로 순간전압강하 보상장치, 정전대책장치, 회생전력 흡수장치 등 적용하는 범위가 광범위하게 확대되고 있다. 전기이중층 Capacitor의 산업용 응용분야로서 제어회로 전원에 많이 사용되고 있는 ATX 전원의 Backup소자로서 전기이중층 Capacitor를 적용하고 있다. 본고에서는 ATX 전원에 전기이중층 Capacitor M-CAP을 응용한 사례를 소개하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.21-22
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• 2011

• Journal of the Korean institute of surface engineering
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• v.26 no.4
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• pp.163-174
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• 1993

The effect of gelatine on the electrodeposition of copper in cupric sulfate-sulfuric acid solution was investi-gated using an ac impedance technique. In the presence of gelatine, the charge transfer resistance was in-creased and the electrical double layer capacitance was decreased. A model was suggested to explain the im-pedance spectra and it fitted well the experimental data. Also the uniformity of deposit thickness was in-creased while the grain size was decreased by the addition of gelatine.