• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.217-222
• /
• 2003

This study was carried out to investigate the geotechnical characteristics and field application of soil mixed with waste lime. Waste lime used in this study is producted as a by-product in the manufacturing process of making Na$_2$CO$_3$from local chemical factory in Incheon. Currently about 320 milton tons of waste lime are accumulated and annually 100,000 tons are producted. In this study, feasible use of waste lime mixed with granited whathered soil, clay, crushed rock was invesigated through laboratory tests including specific gravity test, sieve analysis, hydrometer analysis, compaction test, CBR test. Field investigations were conducted on the road construction site in Incheon.

• Journal of Environmental Science International
• /
• v.13 no.8
• /
• pp.733-737
• /
• 2004

FThe aim of this study was to carry out a preliminary test of the air quality modelling system (HIRES-AIRCHEM) developed at The University of New South Wales, particularly with regard to the forecast ozone distribution. This was achieved by assimilating the New South Wales State Environment Protection Authority (EPA) emissions inventory, consisting of road and non-road sources, and running the system over the Sydney metropolitan area for the four day period 25-28 February 1998. During this period ozone readings exceeded the EPA's goal of 8pphm on several occasions. The model forecasts of ozone distribution verified well with the EPA's ozone readings. This result has important implications for possible future use of the system as a tool for routinely predicting and assessing air quality.

• Journal of the Korean Mathematical Society
• /
• v.48 no.6
• /
• pp.1285-1325
• /
• 2011

We solve the isoperimetric problem, the least-perimeter way to enclose a given area, on various Euclidean, spherical, and hyperbolic surfaces, sometimes with cusps or free boundary. On hyperbolic genus-two surfaces, Adams and Morgan characterized the four possible types of isoperimetric regions. We prove that all four types actually occur and that on every hyperbolic genus-two surface, one of the isoperimetric regions must be an annulus. In a planar annulus bounded by two circles, we show that the leastperimeter way to enclose a given area is an arc against the outer boundary or a pair of spokes. We generalize this result to spherical and hyperbolic surfaces bounded by circles, horocycles, and other constant-curvature curves. In one case the solution alternates back and forth between two types, a phenomenon we have yet to see in the literature. We also examine non-orientable surfaces such as spherical M$\ddot{o}$obius bands and hyperbolic twisted chimney spaces.

• Journal of the Korean Chemical Society
• /
• v.28 no.4
• /
• pp.244-250
• /
• 1984

Separation and identification of the polycyclic aromatic compounds (PAC) from pyrolysis products of cellulose and lignin were performed using a combination of acid-base solvent partitioning and silicic acid column chromatography with fused-silica capillary column gas chromatography/ mass spectrometry. Sixteen PAC were positively identifited by retention indices and mass spectra data. Both materials produced the same kinds of PAC. But lignin produced much more PAC than cellulose. Almost no highly carcinogenic heterocyclic PAC containing nitrogen and sulfur were produced.

• Proceedings of the Safety Management and Science Conference
• /
• 2007.11a
• /
• pp.503-516
• /
• 2007

USA has distinct differences of economic policy by a ruling party. And, USA economy has mainly influenced on it of Korea. So, we examine whether a ruling party of Korea has different regime including rate of return in stock market. The Republican Party and Democratic Party have based on Milton Friedman and Keynes economy at each other's economic policy in the USA The Republican Party and Democratic Party have different interest level and excess return on equity, GDP growth rate, unemployment rate. Also, a ruling party of Korea has different regime and economic activity in this paper.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.212-215
• /
• 2003

The aim of this study was to test the air quality modelling system (HIRES-AIRCHEM) of The University of New South Wales particularly with regard to forecast ozone distribution. This was achieved by assimilating the New South Wales State EPA emissions inventory consisting of road and non-road sources and running the system over the Sydney metropolitan area for the four day period 25-28 February 1998. During this period ozone readings exceeded the EPA＇s goal of 80ppb on several occasions. The model forecasts of ozone distribution verified well with the EPA＇s ozone readings. This result has important implications for possible future use of the system as a tool for routinely assessing air quality.

• Journal of the korean Society of Automotive Engineers
• /
• v.15 no.2
• /
• pp.105-111
• /
• 1993

내연기관의 혼합 가스 생성 장치로 흡입되는 공기의 유량을 조절하기 위해 Butterfly 밸브가 사용 된다. 이 밸브는 유량의 제어에는 매우 유용한 반면, 밸브 후면에서의 복잡한 공기의 유동현상[6] 으로 인하여 혼합가스의 생성에 장해적인 요소를 제공하기도 한다. 특히 밸브가 많이 닫힌 상태 에서는 밸브와 관로벽 사이의 간격이 좁아지는 Throttling 현상으로 인하여, 엔진에 고 부하시 흡 입되는 공기의 양이 증가하게 되어, 밸브 주위에서 공기 속도의 급증으로 인하여 유동장의 압축 성 현상을 기대할 수 있다. Throttle의 Choking 현상으로 인하여 공기의 입자는 운동에너지를 잃 게 되고, 궁극적 혼합가스의 생성에 영향을 미쳐 엔진성능의 저하를 초래하게 된다. 본 연구에서 는 실제 엔진(Central Fuel Injection Engine, 5 liters) [1]의 흡인 manifold를 modelling하여, 특히 밸브가 많이 닫힌 상태에서, 밸브 주위에서의 난류 유동의 압축성 현상을 정량적으로 분석해 보았다.

• Journal of the korean Society of Automotive Engineers
• /
• v.14 no.1
• /
• pp.47-53
• /
• 1992

대도시의 자동차 배기가스에 의한 대기오염문제는 날로 심화되어 가고 있으며, 그 규제 역시 매 우 엄격해지고 있다. 배기가스의 문제는 연소실내에서의 고효율연소에 의해 개선될 수 있으며, 이 를 위해서는 혼합가스 생성장치에서의 잘 미립화된 혼합가스의 생성에 관한 미시적 연구가 필수 적이다. 본 연구에서는 범용 유체 유동해석, 프로그램을 이용하여 Butterfly밸브 주위에서의 공기 의 흐름현상을 예측하였으며, 밸브의 손실계수(Kv)를 실험치와 비교하여 보았다. 또한 압축성과 비압축성 유체 유동해석의 비교, Residual Mass(R. M)의 최적치 정의에 의한 CPU 시간의 최소 화, Numerical Grid Size의 해석결과에 미치는 영향 등에 관해 알아보았다.

• Journal of the Optical Society of Korea
• /
• v.12 no.2
• /
• pp.79-87
• /
• 2008

We have developed a miniature fisheye lens with $190^{\circ}$ field of view operating simultaneously in the visible and the near infrared wavelengths. The modulation transfer function characteristic for the visible wavelength is sufficient for a mega-pixel-grade image sensor. The lens also has a fair resolution in the infrared wavelength region. The calibrated $f-{\theta}$ distortion is less than 5%, and the relative illumination is over 90%. In consequence, a sharp wide-angle image can be obtained which is uniform in brightness over the entire range of field angles. The real image heights for the visible and the near infrared wavelengths have been fitted to polynomial functions of incidence angle with sub-pixel accuracies. Combined with the near equidistance projection scheme of the lens, this lens can be advantageously employed in various image-processing applications requiring a wide-angle lens.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.796-802
• /
• 2014

South Korea is recently under serious situation in supplying electricity with enough power reserve. A single fault of power plant at a peak-load time may lead to a total blackout for whole area connected by a single electric grid and isolated from other grids. Despite of the seriousness of blackout, however, there are scarce studies with ex-ante analysis of the economic costs from blackout. In order to evocate the seriousness, we calculate the economic costs for both industrial and household sectors with using some survey data and statistical methodologies. As a result, total economic costs are 39.23 trillion KRW (35.83 trillion KRW for industrial sector, 3.40 trillion KRW for household sector).