• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.735-737
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• 2002

A current transformer for measuring current in high power testing laboratory is exactly proportional to the current including D.C component due to electrical transient. But, current transformer isn't designed to consider D.C component, therefore when data acquisition system measure that current. the error is increased because of saturation of core. This paper describe the concept of transient factor and how to design the current transformer.

• Journal of the Korea Institute of Building Construction
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• v.1 no.2
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• pp.174-178
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• 2001

This study was performed to control the thermal crack of the mat footing slab in the multi-purposed buildings. In this study, we executed the mixing design of concrete to satisfy the workability and the quality according to the site conditions. And, we evaluated quantitatively about the possibility of thermal crack by using hydration heat analysis system. Finally, we proposed the optimal mixing conditions, curing methods and curing period which all factors are considered. As a result, the optimal mixing conditions were : W/B 41%, unit binder 375kgf/$\textrm{m}^3$, FA replacement ratio 20%. Lowest thermal stress was 22.0kgf/$\textrm{cm}^2$ and at that time thermal crack index was over 1.5, when the coefficient of thermal conductivity was lowest among the curing conditions. And, the total curing time was estimated at 6.7 days according to curing steps.

• Economic and Environmental Geology
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• v.23 no.3
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• pp.359-366
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• 1990

Field sampling requires statistical description to draw inferences from data. Field data, or linear structures, are commonly analyzed by the graphical presentations, such as streonets and rose diagrams. For this purpose the DROPOL program is developed to analyze the data more efficiently with personal computer. DROPOL program written in FORTRAN 77 plots the structural data in points, poles or great circle on equalarea (Schmidt net) or equal-angle (Wulff net) projection surface. It is also capable to project the data from upper or lower hemisphere of stereonet and to draw pole contour diagrams from the plotted data. The rose diagram, representing the frequency of the strike and dip angle, can also be drawn in general or smooth type using $5^{\circ}$ or $10^{\circ}$ degrees interval.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.342-346
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• 2012

This paper presents a loop impedance(inner loop impedance & external impedance) measurement method in TN system. When the measurement of a loop impedance then the measurement result have a some error by load condition. In this paper suggest the loop impedance measurement on actual loading condition by two experiment. one was laboratory condition and the other was the actual measurement on site. Analysis result, measuring error by load condition has not effect on measuring loop impedance.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.235-237
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• 2007

본 연구는 현장 분진포집에 의한 도전율측정과 전기설비 위험을 평가한 것이다. 현장에서의 분진발생은 전기설비에 악영향을 주어 전기설비의 운영시 발생되는 것과 주변환경적 요인에 의해 발생되는 분진이 주를 이루고 있다. 현장에서 포집된 분진으로부터 분진의 종류, 도전율 특성에 의해 전기설비가 영향을 미칠 것으로 판단되었다. 또한 일부 부식성 가스에 의해 노출된 전기설비의 위험성을 분석하고 관리기준을 마련할 필요가 있는 것으로 나타났다. 분진의 종류에 따라 사고의 과정은 빠르거나 오랫동안 지속되었다가 발생되는 근원적 원인을 규명하고자 국내현장에서 분포되고 있는 분진의 종류와 특성 분석과 관련규정을 검토하고 현장실태에서 나타난 문제점을 검토하여 분진발생지역에서의 전기설비 안전관리를 위한 기준마련에 이용될 것으로 기대된다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.349-352
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• 2007

It is impossible to database(DB) the patterns of cable events and cause analysis of faulted cable because the product liability(PL) law have been enforced in Korea, since 2002. In additions, simulation and pattern of cable events are needed for DB system under accelerated deterioration. In this paper, we tested for resistance to nicking of cable below the 22.9kV class due to thermal stresses. This method of exam is following IEC 60811-3-1(Common test methods for insulating and sheathing materials of electric cables). First of all, set the cable in the thermal stress instrument, temperature changed from -20 degree to 120 degree. After thermal stress, we observed a surface crack of cable through microscope and carried out AC withstand voltage test.

• Journal of the Korean Chemical Society
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• v.44 no.1
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• pp.87-91
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• 2000

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.463-464
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• 2009

This paper describes the political and technical trends of foreign 10 countries advanced in solar energy field. In the trend analysis, a couple of statistical data and related references were compared. As a result, all of the advanced countries mentioned in this paper have their own PV policy strategies and regulatory frameworks to strengthen their stable market structures and have financially supported by various types of incentives and tariff systems. It was confirmed that the political basis and technical regulations including electrical safety have to be prepared as soon as possible at both national and rural level in this country.

• Environmental Analysis Health and Toxicology
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• v.17 no.4
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• pp.273-284
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• 2002

At present, the health risks associated with the natural radionuclides of ground water have become a concern as potential social problems. However, there are no regulatory actions or control strategies for such risks. Therefore, we have investigated and discussed the risks and associated management strategies for radionuclides in other countries. US EPA has proposed MCL (300 pCi/L) and AMCL (4,000 pCi/L) for radon, and 30 ppb for uranium, 15 pCi/L for gross-alpha and 5 pCi/L for radium as final MCLs. Also, Canada, WHO and European countries have their inherent management levels. Finally, we suggested several criteria for setting guidelines in our countries including exposure related criteria such as geological distribution, occurrence, exposure probability distribution, exposure population and multimedia exposure assessment, acceptable risk, and cost -benefit analysis. The national-scale exposure and risk assessment, and economic analysis should be conducted for producing and aggregating the representative information on these criteria.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.210-214
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• 2001

GlcNAc 2-epimerase gene from human was cloned. However GIcNAc 2-epimerase was expressed in E. coli as inclusion body formation. Several approaches were tried such as expression in low temperature and low concentration of IPTG. With these treatments production of active form of human GIcNAc 2-epimerase ι ,vas enhanced. For the direct synthesis of NeuAc from GlcNAc and pyruvate, NALase and GlcNAc 2-epimerase were characterized in terms of temperature effect on activity. equilibrium and stability, inhibition by pyruvate etc. For cheap and ease preparation of both the NALase and GlcNAc 2-epimerase, pEN24ma vector was made. which express both the NALasc and GIcNAc 2-epimerase simultaneously. In addition, E. coli BL21(DE3) harboring two plasmids was also made. Of the two systems, the latter was better for the expression of both enzymes.