• 한국도로학회논문집
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• 제16권3호
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• pp.21-33
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• 2014

PURPOSES : This study presents a specific methodology for air dispersion analysis of urban areas methodology in accordance with urban planning and transport policy. METHODS : This study performed three alternatives including development density and public transit applying integrated urban model for the Delft city on Netherlands. Based on this result, the two types of air pollutant emissions($PM_{10}$, NOx) were calculated and analyzed the emission dispersion on that City. RESULTS : As a result, the quality of air near the City is better than that of current conditions showed that approximately from 2.1 to 7.9% according to alternatives. CONCLUSIONS : Air quality assessment in urban areas can be reasonably performed by applying a methodology when urban development and transport policy are considered.

• Fisheries and Aquatic Sciences
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• 제6권3호
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• pp.160-163
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• 2003

Mortality of several species of fish and shellfish exposed to Harmful Algal Blooms (HABs) caused by Cochlodinium polykrikoides, Heterosigam akashiwo, Alexandrium tamarense, Eutreptiella gymnastica, Heterocapsa triquetra and Prorocentrum micans was studied. When fish were exposed to a cell density of 8,000 cells $mL^{-1}$ in C. polykrikoides, $35\%$ of flatfish and darkbanded rockfish died within 48 hrs. However, jacopever rockfish had mortality of higher than $85\%$. Rock bream, filefish and red sea bream showed $100\%$ mortality within 10 hrs with an exposure cell density of 8,000 cells $mL^{-1}$. The rest of HABs except for C. polykrikoides showed that there was no fish and shellfish death throughout the 48 hrs even in the maximum cell density of 100,000 cells $mL^{-1}$ These results imply that C. polykrikoides can have a serious impact on fish mortality and it is regarded as an ichthyotoxic dinoflagellate. The fish death may be attributed to anoxia caused by a combination of the production of reactive oxygen species (ROS) and polysaccharide from C. polykrikoides during blooms.

• 한국항해항만학회지
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• 제35권10호
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• pp.793-798
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• 2011

전자해도는 종이해도 간행을 위한 수치해도를 변환하여 편집되며 그리드 형식의 격자형 체계로 간행된다. 이에 따라 전자해도의 수심정보 밀집도가 일관적이지 못해, 정보 분포에 관한 개선이 요구되어 왔다. 본 연구에서는 위성영상 분류기법 중 K-Means 기법과 ISODATA 기법을 검토 하여, 이를 전자해도 수심정보에 맞게 수정 및 적용 하였다. 전자해도 수심 밀집도 개선기법은 전자해도 로딩 부분, 수심 밀집도 개선 부분, 전자해도 쓰기 부분으로 설계 및 개발하였으며, 개발결과에 조건식에 따른 변수 설정을 달리하여 수심 밀집도 개선 및 변경 결과를 확인하였다.

• 한국주조공학회지
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• 제42권6호
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• pp.392-397
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• 2022

In order to compliant the stringent exhaust emission regulations, higher fuel efficiency and cleaner exhaust gas in combustion engines have been required. To improve combustion efficiency, an exhaust gas temperature is increasing, therefore higher temperature resistance is required for components in exhaust system, especially turbine wheel in turbocharger. IN100 looks quite attractive candidate as it has high temperature properties with low density, however it has low castability due to poor ductility at high temperature. In this study, the balance of Al and Ti composition was optimized from the base alloy IN100 to improve the high temperature ductility by expanding the γ single phase region below the solidification temperature, while obtaining the high temperature strength by maintaining the volume fraction of γ' phase equivalent to IN100 around 1000℃. Furthermore, the high temperature creep rupture life increased by adding a small amount of Ta. The alloy developed in this study has high castability, low density and high specific strength at high temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.107-109
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• 2005

This paper presents the development of the magnetic position sensor for servo motor. The magnetization system is designed for the sinusoidal magnetic flux density distribution from permanent magnet using 2D finite element method and Preisach model. The magnetic position sensor is composed of the permanent magnet and two Hall elements. And the algorithm calculating the rotating position is suggested by the phase difference of outputs of Hall elements.

• Current Photovoltaic Research
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• 제2권2호
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• pp.59-62
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• 2014

Minority carrier diffusion length is one of the most important parameters of solar cells, especially for short circuit current density (Jsc). In this report, we proposed the calculating method of the minority carrier diffusion length ($L_n$) in CIGS solar cells through biased quantum efficiency (QE). To verify this method's reliability, we chose two CIGS samples which have different grain size and calculated $L_n$ for each sample. First of all, we calculated out that $L_n$ was 56nm and 97nm for small and large grain sized-cell through this method, respectively. Second, we found out the large grain sized-cell has about 7 times lower defect density than the small grain sized-cell using drive level capacitance profiling (DLCP) method. Consequently, we confirmed that $L_n$ was mainly affected by the micro-structure and defect density of CIGS layer, and could explain the cause of Jsc difference between two samples having same band gap.

• 한국지리정보학회지
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• 제10권2호
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• pp.36-46
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• 2007

도시의 외연적 확산은 도시 주변부의 농지나 녹지지역을 도시적 용도로 전환시킨다. 도시주변부의 개발은 도시기반시설의 설치비용 및 교통비용 등 여러 가지 사회적 비용을 수반한다. 도시의 확산과정에서 새롭게 개발되는 도시 주변부의 개발특징을 파악하고 이를 합리적으로 관리하는 것은 지속가능한 도시발전을 위한 중요한 과제이다. 본 연구는 대구광역시를 대상으로 1990년과 2000년 사이 도시주변부의 신개발지를 대상으로 위성영상, 토지관리정보시스템, 인구 및 주택총조사 자료 등을 GIS로 구축 활용하여 토지이용전환에 영향을 주는 요인, 토지이용현황 및 공간적 분포, 개발 밀도 등을 중심으로 개발특성을 도출하였다. 분석결과 대구광역시의 도시지역의 확장은 주거지 개발이 주도한 가운데 지역에 따라 산업단지 및 유통단지 등의 형태로 토지이용의 차이를 보였다. 이러한 결과를 기초로 도시개발의 입지, 규모, 밀도 등의 도시성장관리에 필수적인 다양하고 유용한 정보를 제공할 수 있었다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권5호
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• pp.203-210
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• 2003

This paper describes high voltage and high energy density capacitor developed for pulsed power applications. The rated voltage of the developed capacitor is DC 22 [kV], the capacitance is 206 [$\mu$F] and the energy density is about 0.7 [kJ/kg]. Polypropylene film and kraft paper were used as the dielectrics. The ratio of the thickness of each dielectric material which consists of the composite dielectric structure, stacking factor and the termination method were determined by the charging and discharging tests on model capacitors. In terms of energy density, the developed capacitor has higher energy density compared with the products of foreign leading companies. In addition, it has been proved that the life expectancy can be more over 2000 shots through the charging and discharging test. The voltage reversal factor was 20%. This capacitor can be used as numerous discharge applications such as military, medical, industrial fields.

• 한국분무공학회지
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• 제4권2호
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• pp.40-46
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• 1999

Experimental investigation of unsteady impinging diesel spray on the flat plate have been carried out using high speed camera and Malvern system. The density ratios of ambient gas to diesel fuel were varied using $N_2$ and Ar gas in the case of 14.9, 21.2, 28.4, 35.1, 40.4, and 50.1. With the increase of gas density ratio, the radial penetration is decreased due to the resistance of the ambient gas. With the increase of the gas density ratio and the distance between nozzle tip and flat plate, the height of spray is increased due to the entrance and circulation. With the increase of gas density ratio, SMD is decreased on the nearby position at the center of flat plate, but SMD is increased on the far position. As the distance between nozzle tip and flat plate is increased, SMD is always decreased.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.197-198
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• 2006

The high pressure compaction without internal lubricant and the high green density even with the pore free density were achieved by the newly developed die wall lubricant for warm compaction. This developed die wall lubricated warm compaction followed by high temperature sintering resulted in not only the superior mechanical property but also the low dimensional change. In this paper, the effects of increasing the green density on the sintered density, the dimensional change and the mechanical property are mainly discussed