• 조명전기설비학회논문지
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• 제21권8호
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• pp.34-43
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• 2007

본 연구에서는 배전시스템 안정성의 요소라 할 수 있는 고조파, 전압변동, Sag/Swell, 신뢰도의 측면에서 배전시스템을 전력품질 측면에서 안정성을 종합적으로 평가하는 방법을 개발하였다. 시스템이 전력품질의 측면에서 얼마나 안정적인가를 정량적으로 평가하기 위해서 AHP(Analytic Hierarchy Process)를 사용하여 종합 전력품질 통합지수를 산정하는 방법을 제안하였다. 또한 몬테카를로 시뮬레이션을 수행함으로서 사고를 고려한 배전계통의 안정성을 평가하였다.

• 한국연초학회지
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• 제28권2호
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• pp.130-135
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• 2006

This study was carried out to improve the analytical methods for determination of organic acids in tobacco leaf by HPLC. The samples for HPLC analysis were pre-treated by means of SPE. The calibration curve for each acid was linear and $R^2$ values ranged from 0.9990 to 1.0000. The limit of detection were obtained from the calibration curves and their values were between 1.39 to $4.87{\mu}g/mL$. Recovery rates of organic acids were between 88.6 % to 98.5 %. The concentrations of organic acids among the various tobacco leaves were compared to the concentration of organic acids, were in the order oriental, burley, flue-cured tobacco. In the case of flue-cured and oriental tobacco leaves, the order of concentration of organic acids was malic acid, oxalic acid, citric acid. But in the case of burley tobacco leaves, the order of concentration of organic acids was citric acid, oxalic acid, malic acid.

• 한국연초학회지
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• 제28권2호
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• pp.144-151
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• 2006

A measurement uncertainty for analysis of volatile organic compound (benzene) in cigarette mainstream smoke was carried out. In this study one point re-calibration method was used to estimate uncertainty for benzene. The measurement uncertainty was calculated based on the uncertainty sources of each analysis step, quality appraisal sources, drift and repeatability. As a result, the concentration and expanded uncertainty of benzene in cigarette mainstream smoke were measured as $38.08{\pm}4.36{\mu}g/cig$. Relative uncertainty of drift and repeatability obtained were 5% and 3%, respectively.

• Archives of Plastic Surgery
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• 제33권2호
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• pp.168-174
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• 2006

For over two thousand years, many artists and scientists have tried to understand or quantify the form of the perfect, ideal, or the most beautiful face both in art and in vivo(life). However, this mathematical relationship has been consistently and repeatedly reported to be present in beautiful things. This particular relationship is referred to as the golden ratio. It is a mathematical ratio of 1.618 : 1 that seems to appear recurrently in beautiful things in nature as well as in other things that are seen as beautiful. Dr. Marquardt made the facial golden mask that contains and includes all of the 1-dimensional and 2-dimensional geometric golden element formed from the golden ratio. The purpose of this study is to evaluate the usefulness of the golden facial mask. In our cases(n=40), the authors applied the facial golden mask to the preoperative and postoperative photographs, and scored each photograph. Compared with the average scores of the facial mask applied photographs and none applied photographs using non-parametric test, statistical significance was not checked (p > 0.05). It means that the facial golden mask can be used for facial analysis. The facial golden mask is easy to apply, cheap and relatively objective. So, the authors introduce the one of useful facial analyses.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.87-93
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• 2005

본 논문에서는 측정${\cdot}$분석을 수행한 인천국제공항 여객터미널의 전력계통에 고조파 저감을 위한 고조파필터를 설계하여 이를 적용하였다. 특히 고조파를 다량 발생시키는 기기들에 대하여 향후 대표스펙트럼 선정을 위하여 고조파 측정을 수행하였다. 또한 EDSA를 사용하여 Simulation을 수행하여 수동필터의 고조파 저감효과를 분석하였으며, 또한 APF(Active Power Filter)와 ZSF(Zero Sequence Filter)의 설계를 수행하였다.

• 한국대기환경학회지
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• 제27권6호
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• pp.672-680
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• 2011

Three new granular absorbents were prepared from calcium hydroxide, and applied to an FGD process with internal circulation. The aim of the study was finding the most efficient of the these three applied absorbents for the $SO_2$ removal at high flue gas temperatures. The absorbent is fed to the testing unit at high operation temperature and fluidized inside the FGD system where the sorbent particles react with the $SO_2$ gas. The rate of $SO_2$ decomposition was high in C-type absorbent which had the large surface area. De-SOx characteristics of the current absorbents appeared to be similar to the other conventional agents in this fluidized bed combustor. In particular, the optimum de-SOx condition could be achieved at high mole ratios of Ca to S which can reduce the residual $SO_2$.

• 한국연초학회지
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• 제28권1호
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• pp.51-57
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• 2006

This study was carried out to improve and evaluate the analytical method for determination of potassium in tobacco leaf by various pre-treatment techniques. The time requirment of various pre-treatments was about 10 hour for dry ashing and 6 hour for microwave digestion and 3 hour for sonication. The results of recover in both pre-treatment techniques, microwave digestion and sonication, is greater than 85 % stably with reproducibility(RSD %) on replicates of less than 3 %. However the mean values for microwave digestion were lower than certified standard value of NlST SRM. Compared to the other pre-treatment techniques, analytical results for sonication technique strictly improved the accuracy and precision. In conclusion, the use of the simple sonication technique seems to be efficient for the determination of potassium in tobacco leaf in consideration for both the accuracy and reproducibility.

• 한국연초학회지
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• 제27권2호
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• pp.219-225
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• 2005

Characterizing nicotine delivery from tobacco products is important in the understanding of their addictive potential. Most previous studies report total nicotine and have not differentiated between nicotine in its protonated or free-base form. The amount of free nicotine calculated by determining pH and nicotine contents. The pH and nicotine contents in smokeless tobacco product, tobacco products and tobacco leaves were analyzed by Health Canada-Official Method T-310 and CORESTA Recommended Method $N^{\circ}62$. The content of free nicotine was calculated according to the Henderson-Hasselbalch equation and the value of $\alpha_{fb}$(the fraction of nicotine that is in the free base form) by using a pKa value of 8.02 for nicotine. The percentage of free nicotine then was calculated by dividing the free nicotine content by total nicotine content. The pH value and percentage of free nicotine ranged from 5.01 to 5.45 and $0.10\%\;to\;0.27\%$ in cut tobacco and 5.10 to 7.10 and $0.12\%\;to\;10.73\%$ in tobacco leaves, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.154-157
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• 1990

This paper describes a new method of calculating expected energy generation and loss of load probability (L.O.L.P) for electric power system operation and expansion planning. The method represents an equivalent load duration curve (E.L.D.C) as a mixture of cumulants approximation (M.O.C.A), which is the general case of mixture of normals approximation (M.O.N.A). By regarding a load distribution as many normal distributions-rather than one normal distribution-and representing each of them in terms of Gram-Charller expansion, we could improve the accuracy of results. We developed an algorithm which automatically determines the number of distribution and demarcation points. In modelling of a supply system, we made subsets of generators according to the number of generator outage: since the calculation of each subset's moment needs to be processed rapidly, we futher developed specific recursive formulae. The method is applied to the test systems and the results are compared with those of cumulant, M.O.N.A and Booth-Baleriaux method. It is verified that the M.O.C.A method is faster and more accurate than any other methods.

• 항공우주시스템공학회지
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• 제7권2호
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• pp.1-7
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• 2013

Recently, there are a number of studies over dynamic analysis for minimizing vibration of flexible structures such as solar panel for agility of high-agility satellite. The traditional studies perform dynamic analysis of a solar panel assumed as rigid structure since the stiffness of solar panel is higher than the stiffness of solar panel's hinge spring. However, there are vibrations that have modes of bending and torsion when high-agility satellite rotate speedily. This vibrations result in delaying safety time of satellite or degrading image quality. This paper presents dynamic analysis's technique of satellites including the spring hinge of solar panel and flexible structural solar panel's effects described as the linear equation of motion using Lagrange's theorem, and verifies the validity of an established dynamic analysis's technique of satellites by comparing the finite element method. In addition high-agility satellite's dynamic characteristics of a torque profile are analyzed from the established dynamic analysis's technique of satellites.