• 자원ㆍ환경경제연구
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• 제11권3호
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• pp.377-396
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• 2002

This paper investigates whether an inverted U relationship between pollution and economic development could be found in the Seoul metropolitan region using a panel data for the period of 1985~1999. We uses a model with a more flexible random coefficients specification which allows for a greater degree of regional heterogeneity. The emissions of sulfur dioxidetotal($SO_2$), suspended particulates(TSP), nitrogen dioxide($NO_2$), and carbon monoxide(CO) were selected as four major pollutants. We found that the emissions of these pollutants per capita except sulfur dioxidetotal exhibited inverted U shapes with per capita gross regional domestic product (GRDP). We also noted that the turning points for Seoul metropolitan region occured at a range of incomes, from $3,000 to $5,000 per capita.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.215-220
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• 2004

The TIER-LII system was established and evaluated using carbon black for diesel particulate size measurement. It contains a new designed sensor head which makes it easier to be measured. Through LII signal analysis of some parameters, we can understand that there were few correlations observed in effect of temperature, shield gas flow rate, and mixture flow rate.. However, an amount of difference was observed in different size of particulates.

• 한국대기환경학회지
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• 제2권3호
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• pp.11-18
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• 1986

In order to evaluate the state of the environmental pollution by vehicle exhaust in Seoul area the correlation between lead in air and leaves of roadside trees has been investigated during August in 1985. The dust in the atmosphere was collected by high volume air sampler to measure the concentration of lead. On the other hand, lead as a pollution indicator was extracted from the leaves of roadside trees (Ginkgo biloba, Salix pseudo/lasiogyne, platanus occidentalis) by conventional method and their concentrations were determined. The following results were obtained : 1. Lead concentrations in the leaves of roadside trees varied with trees, for example, the average concentrations of lead in each of the leaves of Ginkgo biloba, Salix pseudo/lasiogyne and Platanus occidentalis were 20.66 ppm, 9.37 ppm, and 10.58 ppm, respectively. 2. The dust sampled along heavily traveled highways showed that lead content tended to increase with traffic volume. 3. The correlation coefficients between lead correlation in air and leaves of Gingo biloba, Salix pseudo/lasiogyne, and Platanus orientalis were 0.80, 0.85, and 0.87, respectively.

• 환경위생공학
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• 제14권2호
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• pp.68-74
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• 1999

The atmospheric concentrations of Nitrogen Dioxide ($NO_2$) and Total Suspended Particulates (TSP) at the traffic road side were measured n Asan area, Choongchumg-namdo during May 1998 and January, 1999.The results of the study are as follows;1. The aversge value of airbone $NO_2$ and TSP levels were 28.5ppb and 5.9mg/me in Asan area. 2. The concentration distribution of NO2 and TSP is high for the season of winter. On a daily pattern, somewhat high value is appeared in the afternoon. 3. For the station, terminal, and Shinchang, the average value of $NO_2$ is 33.6ppb, 27.9ppb and 24.1ppb in sequence, and the ones of TSP is 6.3mg/m3, 6.0mg/m3 and 5.3mg/m3 in order.4. The high levels of $NO_2$ and TSP were positively related to traffic volume.

• 소성∙가공
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• 제9권5호
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• pp.494-503
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• 2000

The electro-magnetic stirring and mechanical process were applied to fabricate particulate metal matrix composites(PMMCs) with various particle size. The mechanical test on PMMCs was carried out in order to clarify the effect of 76 heat treatment on tensile behaviors. In order to study the thixoforming of PMMCs, fabricated billet are reheated by using the coil designed as a function of length between PMMC billet and coil surface, coil diameter and billet length. The effect of reinforcement distribution on billet temperature variation has been investigated with the calculated solid fraction theory based on a function of matrix alloy and volume fraction of reinforcement.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.89-93
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• 2003

Daily average concentrations of fine particulates have been measured simultaneously in Seoul and Asan area by using PM minivolTM portable air sampler(Air Metrics, U.S.A) from September 2001 to August 2002. The sampler were analyzed by ICP-OES(inductively coupled plasma optical emission spectrometry, optima 3000DV, Perkin Elmor) to determine the fine particulate concentrations of metallic elements(As, Mn. Ni, Fe, Cr, Cu, Cd, Pb, Zn, Si). The concentration of PM$\sub$2.5/ showed a high trend in the Seoul area. Zn showed a similar distribution ratio for the fine particle in both Seoul and Asan. Mn and Fe, Cr, Cd are highly correlated in the Seoul and Asan area(P<0.05).

• 한국세라믹학회지
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• 제30권6호
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• pp.429-432
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• 1993

Cr3C2 material is characterized by high chemical stability and poor sinterability with low strength [50~150MPa]. In his study, low melting temperature nickel powder was used to improve sinterability as well as strength. In addition, molydenum particles were added to the Ni-bonded Cr3C2 cermet pseudomatrix to increase resistance to fracture. The specimens made by hot-pressing under vacuum and strength was measured by 4-point bending. Indentation cracking and fractographic examination were conducted to study the interaction of the indentation cracks with the reinforcing particles. Toughening mechanisms and failure will be discussed in terms of crack/particle interactions and compared with previous works.

• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.773-787
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• 2003

Principal component analysis, factor analysis and cluster analysis have been performed to analyze the relationship between air pollutants and meteorological variables measured in 1999 in Seoul. In principal analysis, the first principal has been shown the contrast effect between $O_3$ and the other pollutants, the second principal has been shown the contrast effect between CO, $SO_2$, $NO_2$ and $O_3$, PM10, TSP. In factor analysis, the first factor has been found as PM10, TSP, $NO_2$ concentrations which are related with suspended particulates. As a result of cluster analysis, three clusters respectively have represented different air pollution levels, seasonal characteristics of air pollutants and meteorological situations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.389-392
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• 2001

The characteristics of thixoforming process can decrease liquid segregation because of the improvement in fluidity in a globular microstructure state and utilizes flow without an air entrapment. Therefore, in order to obtain the sound parts of metal matrix composites by using thixoforming process which is co-existing solidus-liquidus phase, it is very important to obtain a die design, fabrication conditions which affects the uniformity of the solid fraction on unfilling state and various defects throughout the fabricated parts. The die designs and fabrication conditions to obtain the good piston part are proposed for thixogorging process of metal matrix composites.

• 한국정밀공학회지
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• 제22권8호
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• pp.71-75
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• 2005

This study has been focused on the development of automatic bottle air rinser. It is designed to rinse clean empty bottles prior to filling. The bottles are automatically indexed beneath an air nozzle that has both a clean airjet and vacuum source. The bottle is first given a burst of clean air to loosen any particles from the wall of the bottle. A vacuum sequence follows which removes all particulates into a self contained filter unit. In order to the provide the desired function, analysis is carried out by FEM simulation using FLUENT and CATIA software. The final results of analysis are applied to the design of automatic bottle rinser and the machine is successfully developed.