• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.62-63
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• 2003

대기 중 입자상 및 가스상 오염물질에 대한 오염원의 영향을 확인하고 기여도를 정량화하기 위하여 수용방법론 (receptor methods)이 이용되고 있다. 수용방법론은 각종 응용통계학을 기반으로 한 계량화 학적 분석기술로서, 일반대기 중 수용체에서 가스상ㆍ입자상 오염물질의 물리ㆍ화학적 특성을 분석한 후, 대기질에 영향을 미치는 오염원을 확인하고 기여도를 정량적으로 파악하여 대기오염 관리를 합리적으로 수행할 수 있는 통계적 방법이다. 또한 수용방법론은 입자상 및 가스상 오염물질의 분석에 다각도로 응용할 수 있으며, 합리적인 대기오염 관리를 유도하는 기초기술이라 할 수 있다(황인조 등, 2001). (중략)

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.151-163
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• 2003

In this study, we investigated the physiochemical characteristics of temporal estuarine environment formed during the summer flood season (consecutive rainy days with average 50 mm day$^{-1}$ precipitation) in the coastal area of South Sea of Korea. The freshwater from the Seomjin River was characterized by lower temperature, salinity and pH, and high concentrations of COD and nutrients. In the summer flood season, such peculiar Somejin-River freshwater was dispersed southward along the coast of Yeosubando-Dolsando-Geumodo, form-ing temporal estuarine environment (defined as "Coastal Pseudo-Estuary" in this study) throughout the entire study area (as far as 60 km from the Seomjin River mouth). Compared to the winter dry season, the DIN/DIP ratio was almost doubled (16-36) during the summer flood season. This excessive nitrate supply during the summer flood season was probably due to nitrogenous fertilizer. Distribution and behaviors of physiochemical factors in this coastal pseudo-estuarine environment were controlled not only by the runoff of the Seomjun River (physical mixing of river water with seawater) but also by the biogeochemical estuarine processes which are mostly similar to those of the river estuary.r estuary.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.35-48
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• 2004

This paper provides a comprehensive overview of geochemical approaches for investigating and assessing heavy metal contamination in abandoned mine sites. Major sources of contaminants at the abandoned mine sites are mine water, waste rocks, tailings, and chemicals used in beneficiation and mineral processing. Soil, sediment, surface and ground water, and ecological system can be contaminated by heavy metals, which are transported due to erosion of mine waste piles, discharge of acid mine drainage and processed water, and dispersion of dust from waste rocks and tailings. The abandoned mine sites should be characterized using various methods including chemical analysis, mineralogical analysis, acid generation prediction tests, leaching/extraction tests, and field tests. Potential and practical environmental impacts from the abandoned mines should be assessed based on the site characterization.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.119-126
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• 1999

This study was carried out to estimate the effect of forest fire on physical and chemical properties of soil The forest fire was in April 1995 at Kongju of Chungnam. Soil samples were collected at 0~5cm, 5~10cm, and 10~20cm soil depths in September 1998 from the burned and unburned sites. Soil organic matter concentrations at 0~5cm and 5~10cm soil depths were significantly greater in unburned site than in burned site. Soil concentrations were greater in unburned site than in burned site at all soil depths. Cation exchange capacity was significantly higher in unburned site than in burned site at 0~5cm soil depth. There were no differences in available soil P, exchangeable soil K, Ca, and Mg, and pH of soil between burned and unburned sites. Soil water content at 0~5cm soil depth was significantly greater in unburned site than in burned site. Bulk density at 0~5cm soil depth was significantly higher in burned site than in unburned site. Forest fire had an adverse effect on physical and chemical properties of soil in this study, Burning of vegetation and forest 리oor organic matter in burned site may reduce organic matter supply to soil and increase soil erosion. Consequently, forest fire may have adverse influence on long-term site productivity.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.339-346
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• 2002

Physico-chemical properties of the activated sludges(Suyoung and Changlim treatment plant), such as SVI(sludge volume index), absorbance, specific surface area, and specific resistance using Buchener funnel test were investigated with changing anaerobic storage time. This experimental condition was found that it was possible to estimate a linear relationship between their parameters such as specific surface area specific resistance, and sludge volume index(SVI). The specific surface area and the specific resistance to filtration of the activated sludges of Suyoung and Changlim treatment plant were found as 123.6~136.6$m^2$/gDS and 41.5~44.9$m^2$/gDS(dry solid), and 1.09$\times$10$^{14}$ ~5.48$\times$10$_{14}$ m/kg and 1.05$\times$10$^{14}$ ~2.48$\times$10$^{14}$ m/kg, respectively. The results gave a good linear relationship between the specific surface area and the specific resistance, r=2.25$\times$10$^{12}$ s-8.10$\times$10$^{13}$ ($R^2$=0.8885) at Suyoung treatment plant and r=1.26$\times$10$^{13}$ s-4.75$\times$10$^{14}$ ($R^2$=0.8756) at Changlim treatment plant.

• Explosives and Blasting
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• v.22 no.1
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• pp.81-91
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• 2004

Samples examined in this paper were selected from Samwoo building stone, Sinra building stone, Gana building stone, and Chung gin building stone in Kyunggi province and Whakwang industry, Gomoch building stone, and Sejin building stone in Kyungbuk province. The point of this study is to examine the physical and mechanical features of Pochun rock, Munkyung rock and Ildong rock through specific gravity, porosity, absorption, point load test, triaxial compressive test Brazilian test, petrology test and chemical analysis test.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2001.06a
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• pp.58-59
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• 2001

부산에서 북동쪽으로 대략 25km 떨어진 지점에 위치하고 있는 일광광산 부근의 지질은 백악기 화산암ㆍ퇴적암 그리고 이를 관입한 화강암류와 이 암주 내에 발달하는 구리-중석을 함유하고 있는 각력파이프광상으로 이루어져 있다. 일광광산의 화강암류는 거의 타원형으로 felsic한 중앙부와 mafic한 양상의 주변부로 나뉘어지며, 암주 내에 수직적인 원통형의 각력파이프가 광화대를 이루고 있고, 그 주변에는 모암변질대가 발달되어 있다. 각력파이프를 충진하고 있는 vein과 화강암의 중앙부에는 전기석이 풍부하게 산출되고 있다. 일광광산에서 산출되는 전기석은 야외 관찰시 각력파이프 중심에서부터 외곽부쪽으로 전기석의 풍부함이 감소하며 산출형태도 달라진다. 파이프에서 대략반경 150m내에서 전기석은 침상형 의 방사상 모양 내지 rosettes형으로 풍부하게 산출되며, 화강암내의 mafic한 암편을 치환한 형태로 산출되기도 한다. 암주의 중앙부 주변부에서는 거의 미세한 구상형으로 산재되어 나타나고 있다. 전기석은 복잡한 화학식 {(Na, Ca)(Fe, Mg)$_3$(Al, Li)$_{6}$(BO$_3$)$_3$Si$_{6}$O$_{18}$ (OH, F)$_4$}을 갖는 붕산 규산염광물이다. 이러 한 다양한 성분은 마그마의 진화과정, 모암의 특성, 온도, 압력, 성분과 같은 물리ㆍ화학적 성질에 따라 전기석의 성분이 체계적으로 변하기 때문에 모암과 전기석 기원과의 상관관계를 파악할 수 있다. 파이프 부근의 화강암류는 현미 경상에서 전기석이 석류석과 같이 풍부하게 나타나며 장석들은 변질받은 상태로 세리사이트, 녹렴석으로 나타나고, 흑운모와 각섬석은 녹니석화되어 변질된 상태를 보이고 있다. 파이프 중심에서 외곽부로 갈수록 전기석의 함량은 줄어들고 있고 장석들이 알바이트ㆍ칼스베드 쌍정을 보이며, 흑운모가 각섬석보다는 우세하게 나타나고 있다. 전기석은 주상 결정, 자형 내지 반자형의 입자로 다색성을 보이며, 결정 중심에서 가장자리로 갈수록 파란색과 황갈색의 광학적 누대구조를 관찰할 수 있다. 일광광산에서 산출되는 전기석에 대한 현미경 관찰은 열수기원임을 지시하고 있다. 야외조사와 현미경 관찰의 예비조사에 의하면 일광광산의 전기석이 형성된 환경은 다른2가지 화학적인 저장소의 혼합 효과의 결과로 생성되어진 것으로 예상된다. 일광의 화강암류를 만든 마그마는 전기석을 형성할 만큼의 Fe-Mg성분이 충분하지 않았을 것이다. 화강암 내에 흑운모와 각섬석의 결정작용에 의해 마그마의 Fe-Mg성분이 고갈되어지고 이로 인해 그 함량이 감소하며 상대적으로 마그마 내에 남은 붕소(B$_2$O$_3$)는 열수로 용리되고 흑운모, 각섬석과 평형을 유지하며 열수에 남아있게 된다. 잔류용융체에 남은 붕소의 함량은 전기석을 만들기에 충분함에도 불구하고, Fe-Mg 함량이 부족하여 마그마 기원의 전기석 결정을 만들 수가 없다가 광맥이 형성된 시기에 또 다른 열수가 공급되면서 이전의 평형이 깨지고 기존의 흑운모와 같은 염기성 광물이 붕소(B)를 함유한 새로운 열수와 반응하여 전기석을 형성한 것으로 예상한다. 앞으로 전암과 광물에 대해 지화학적 연구를 통해 화강암류와 전기석과의 지화학적 연관성, 주성분 원소와 열수의 특성과의 상관관계, 전기석의 기원(마그마 기원인지 열수기원인지)이 보다 정확하게 파악될 것이다. 마그마 진화에 따른 전기석의 성분변화와 기원을 이용하여 일광광산의 동광화대를 형성한 마그마 계에서 열수계로 이어지는 지질학적 과정을 이해할 수 있을 것이며, 암석 성인론적 지시자로서 어떠한 중요성을 갖는지 논의되어질 수 있다.

• Explosives and Blasting
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• v.22 no.2
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• pp.33-43
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• 2004

The six grades weathering system is normally used in weathered rock classification. In this study. fresh and weathered rock block of grade I to V were sampled in Jang-soo ana but samples of the grade VI was omitted from this study. The variation quantities of chemical weathering indices with weathering degree are smaller than those of physical and mechanical properties. Increase of Weathering degree is well indicated by physical and mechanical properties such as strength, hardness, ultrasonic velocity and slake durability result. Especially, absorption and porosity ratio is a good indicator. As weathering proceeds. a number of the cracks affect the rock deformation. Therefore, stress-strain curves of weathered rocks in unconfined state are quite different from ones of fresh rocks.

• Polymer(Korea)
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• v.26 no.4
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• pp.535-542
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• 2002

We have prepared the surfactant-free nanoparticles of poly(DL-lactide-co-glycolide) (PLGA) by dialysis method and their physicochemical properties such as particle size and drug contents were investigated against various solvent. The size of PLGA nanoparticles prepared by using dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) was smaller than that from acetone. Also, the order of drug contents was DMAc>DMF>DMSO=acetone. These phenomena could be expected from the fact that solvent affects the size of nanoparticles and drug contents. The PLGA nanoparticles have a good spherical shapes as observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, surfactant-free nanoparticles entrapping norfloxacin (NFx) have a good drug loading capacity without free-drug on the surface of nanoparticles confirmed by the analysis of X-ray powder diffraction. Release kinetics of NFx used as a model drug was governed not only by drug contents but also by particle size. Also, the biodegradation rate of PLGA nanoparticles prepared from DMF was faster than that prepared from acetone, indicating that the biodegradation of PLGA nanoparticles is size-dependent.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.540-548
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• 2002

The purpose of this study is to analyze the application of oyster shells (OS) as aggregates for concrete. For this purpose, five reference mixes with W/C ratios of 0.4 ∼0.6 at intervals of 0.05 were used. The replacement proportion of OS was varied with ratios of 0, 10, 30, 50 and 100％ by volume of fine or coarse aggregate in the reference mixes. OS was washed and crushed for using as aggregates. New chemical reaction between crushed OS aggregate and cement paste was tested through XRD and SEM analysis. Two strength properties (compressive and flexural) were considered. Strength tests were carried out at the ages of 1, 3, 7, 14 and 28 days. The variations of workability, air content and density, drying shrinkage of the specimens with different proportions of OS were also studied. Finally, the hollow concrete block using OS as a substitute material for fine aggregate was made for testing the application of OS. Experimental results showed that my new chemical reaction did not occur due to mixing OS in concrete. The workability and strengths decreased with increase in proportion of OS. The same trend was observed in density and unit weight, but air content increased due to the inherent pores in OS, which showed a possibility to produce light weight concrete with low strength by using OS as coarse aggregates for concrete. Tests on hollow concrete block showed that the compressive strength and absorption ratio were satisfied with quality requirements when the fine aggregate was substituted with OS up to 50％ in volume.