• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.439-439
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• 2011

기존의 고온에서 제작되는 TiO2 나노 입자를 이용한 염료감응형 태양전지를 저온에서 제작하기 위해 전자 이동층으로 ZnO 나노 입자를 사용하여, 저온($200^{\circ}C$)에서 염료감응태양전지(DSSC)를 제작하였다[1,2]. 상대전극(counter electrode)으로는 RF magnetron sputtering을 사용하여 ITO/glass위에 Pt를 증착하여 태양전지의 특성을 측정하였다. $180^{\circ}C$ 이상에서 hydropolymer가 증발되는 것을 이용하여, ZnO 나노입자와 hydropolymer 혼합한 paste 제작하여 소결 후 ZnO 나노입자 사이에 다공성을 생성시켜 Dye가 잘 침투하여 ZnO 나노입자 표면에 잘 흡착 되도록 하였다[3]. 20 nm 및 60 nm 크기의 ZnO 나노 입자를 사용하여 실험 해본 결과, 20 nm에 비하여 60 nm ZnO 나노입자의 경우 IPCE 값이 약 7% 정도로 높은 전환효율 값을 보였다. 60 nm ZnO 나노입자를 전자 수송층으로 사용한 DSSC 소자에서 단위면적당 흐르는 전류(Jsc), 전압 (Voc), fill factor (ff), 그리고 효율(${\eta}$)의 최대값은 4.93 mA/$cm^2$, 0.56V, 0.40, and 1.12%, 로 보였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.376-387
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• 2009

Piled raft foundation is a geotechnical composite construction to support the superstructure by pile-soil-raft interaction. General conventional design for piled raft doesn't consider the contribution of a raft. This is very conservative and requires more piles to satisfy the factor of safety. It is important to evaluate the load sharing features of piled raft. In this research, this characteristics of piled raft evaluated using both centrifuge and numerical modelings. The ultimate bearing capacity of piled raft foundation was also evaluated and predicted through comparisons of ultimate bearing capacity of single pile (SP), unpiled raft (UR), freestanding pile group (FPG) and piled raft (PR). $\xi_{pr}$ and $\eta$ were determined by centrifuge model tests to simply evaluate the ultimate bearing capacity of piled raft and bearing capacity of piled raft was predicted using the calibrated numerical model based on the centrifuge tests and laboratory tests data.

• Journal of the Korea Society of Computer and Information
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• v.22 no.10
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• pp.145-150
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• 2017

This study aims to analyze panel data using OECD Health data of 34 years to examine how significant the inequality of income is to the inequality of health. The data was from OECD's pooled Health data of 32 countries from 1980 to 2013. The process of determining analysis model was as follows; First, through the descriptive statistics, we examined averages and standard deviation of variables. Second, Lagrange multiplier test has done. Third, through the F-test, we compared Least squares method and Fixed effect model. Lastly, by Hausman test, we determined proper model and examined effective factor using the model. As a result, rather than Pooled OLS Model, Fixed Effect Model was shown as effective in order to consider the characteristics of individual in the panel. The results are as follows: First, as relative poverty rate(${\beta}=-19.264$, p<.01) grows, people's life expectancy decreases. Second, as the rate of smoking(${\beta}=-.125$, p<.05) and the rate of unemployment (${\beta}=-.081$, p<.01) grows, people's life expectancy decreases. Third, as health expenditure(${\beta}=.414$, p<.01) shares more amount of GDP and as the number of hospital beds(${\beta}=-.190$, p<.05) grows, people's life expectancy increases.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.415-418
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• 2014

Phenyltrimethoxysilane (PTMS) was anchored onto the sensitized $TiO_2$ nanoparticles. This insulating molecular layer effectively inhibited the charge recombination at the interface of $TiO_2$/electrolyte in the dye-sensitized solar cells (DSCs) without sacrificing the dye-loading capacity of the nanocrystalline $TiO_2$. DSCs using PTMS-modified $TiO_2$ exhibited a short-circuit current ($J_{SC}$) of $15.9mA/cm^2$, an open-circuit voltage ($V_{OC}$) of 789 mV, and a fill factor (FF) of 68.2%, yielding an overall conversion efficiency (${\eta}$) of 8.55% under $100mW/cm^2$ illumination. The resulting cell efficiency was improved by ~10% as compared with the reference cell.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.700-705
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• 2001

Sucrose첨가가 옥수수 전분호액의 레올로지 특성에 미치는 영향에 대하여 평가하였다. 전분호액은 sucrose 첨가에 관계없이 전단담화 비뉴턴 거동(n=0.37-0.58)을 나타내었으며, 또한 sucrose의 농도가 증가함에 따라 점조도지수$(K,\;K_h)$, 겉보기 점도$({\eta}_{a,100})$값은 크게 감소하였고 항복응력$({\sigma}_{oc},\;{\sigma}_h)$도 감소하는 경향을 나타내었다. 전분호액의 겉보기점도에 대한 온도의존성은 Arrhenius식에 의하여 높은 상관관계를 나타내었으며, 활성화에너지는 각각 10.80-15.59 kJ/mole을 나타내었고 농도가 증가함에 따라 감소하는 경향을 나타내었다. 적용된 주파수$({\omega})$ 범위에서 저장탄성률(G#)의 수치가 손실탄성률(G@)보다 높게 나타났으며 sucrose의 농도가 증가함에 따라 감소하여 탄성 및 점성 성질을 감소시켜 주었다. 이들 동적데이터로부터 전분호액은 sucrose 첨가에 의해 더욱 약한 겔과 같은 구조적 성질을 나타냄을 알 수 있었다. 그러므로 sucrose 첨가는 전분호액 내의 입자들의 재회합을 방해하여 전분호액의 레올로지 특성을 변화시킨다. Sucrose 30%를 첨가한 옥수수 전분호액을 제외한 모든 시료들은 이동인자$(shift\;factor,\;\alpha)$를 사용함으로써 Cox-Merz 중첩 원리에 잘 적용되었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.178-181
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• 2008

A solar cell based on dye-sensitized photoelectric conversion was studied by investigating the effects of the amount of polyethylene glycol(PEG), added to the $TiO_2$ paste, on surface morphology of the $TiO_2$ films and on the solar cell performance. Energy conversion efficiency was found to increase with PEG addition up to 20 % by weight of $TiO_2$ and then decrease with further addition due to the aggregation of $TiO_2$ nano particles in the $TiO_2$ film. In this study, the best result of dye-sensitized solar cell was the short circuit current(Isc) of $22.6mAcm^{-2}$, the open circuit voltage (Voc) of 0.73 V, the fill factor (ff) of 0.55 and the overall energy conversion efficiency (${\eta}$) of 9.1 % under illumination with AM 1.5 simulated sunlight.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.143-148
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• 2010

A Statistical methods are used to determine the reliability of a Fuel Boost Pump for aviation. Failures are referenced from failure reports. The failure-free periods between successive failure events are evaluated in the form of weibull distribution. The results of analysis were calculated shape factor, scale parameter and mean time to failure. It found that the reason of failure is wear-out period.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1243-1244
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• 2007

전자주개물질 (elelctron donating material)인 poly(3-hexylthiophene) (P3HT)와 전자받개물질 (electron accepting material)인 티타니아 ($TiO_2$)를 이용한 복합형 태양전지에 대해 연구하였다. 유기물 태양전지에 응용되는 전도성 고분자의 여기자 (exiton)의 확산거리가 매우 짧기 때문에 그것을 보완하기 위해 전자주개물질과 받개물질의 표면적을 넓힐 필요가 있다. 비교적 패턴을 형성하기 쉬운 무기물인 티타니아를 이용해 표면적을 증가시켰으며 그렇지 않은 태양전지에 비해 효율이 두 배 증가하는 것을 볼 수 있었다. 티타니아의 표면적을 증가시킨 태양전지의 개방회로전압 ($V_{oc}$), 단락회로전류 ($I_{sc}$), FF (fill factor) 및 효율 (${\eta}$)은 각각 560 mV, 0.657 mA, 48.3 %, 0.18% 이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.651-653
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• 2000

In this study, a distance-measurement system was proposed by using principle of the Michelson Interferometer and a fundamental research was carried out. In case of the rnichelson interferometer, relativity distance was measured by relativity-difference of two course of light. But wavelength of light source were changed in this system in order to use interference phenomenon of michelson interferometer in measuring absolutely distance. Wavelength of input signal were changed periodically and were interfered electrically. So absolute distance can be calculated by using $\Delta\lambda$ and measuring $\eta\Delta$ in electric interference. Nose by a external factor was small in this system because a absolutely distance was measured by phase difference. And a dispersion of noise was small in pulse-echo response because a error was occurred in range of phase difference of signal. Also very wide range can be measured by only single system because informations of distance were acquisited in wavelength level.

• Solar Energy
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• v.10 no.3
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• pp.60-65
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• 1990

[ $n^+-p^+$ ] InP homojunction solar cells were fabricated by thermal diffusion of sulphur into a $p^+$-InP wafer($p=4{\times}10^{18}cm^{-3}$), and a SiO film($600{\AA}$ thick) was coated on the $n^+$ layer as an antireflection(AR) coating by an e-beam evaporator. The volume of the cells were $5{\times}5{\times}0.3mm^3$. The front contact grids of the cells with 16 finger pattern of which width and space were $20{\mu}m$ and $300{\mu}m$ respectively, were formed by photo-lithography technique. The junction depth of sulphur were as shallow as about 0.4r m We found out the fabricated solar cells that, with increasing the diffusion time, short circuit current densities($J_{sc}$), series resistances($R_s$) and energy conversion efficiencies(${\eta}$) were increased. The cells show good spectral responses in the region of $5,000-9,000{\AA}$. The short circuit current density, the open circuit voltage( $V_{oc}$), the fill factor(F.F) and the energy conversion efficiency of the cell were $13.16mA/cm^2$, 0.38V, 53.74% and 10.1% respectively.