• Journal of the Korean earth science society
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• v.23 no.8
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• pp.683-696
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• 2002

In this work. we investigated the ozone data sets that exceeded ambient air quality standards from 31 air quality monitoring stations dispersed across the Seoul metropolitan city during the period covering 1990 and 2000. To specifically describe spatial dependency of high level O$_3$ occurrence, we grouped our data into four different geographical ozone exceedance is much longer in SW than the other three sectors. When we compared the exceedance data in terms of occurrence frequency, the month of maximum frequency differed slightly among different sectors. Examination of long-term exceedance trend indicated that its frequency increased continuously from all sectors over the past years, although slightly opposite patterns existed in their absolute values. Most importantly, its peak occurrence frequency seemed to center in very recent years such as 1998 (NE sector) and 2000 (ail pattern sectors except NE). Consequently, we were able to describe the existence of certain patterns of ozone exceedance data sets in terms of both temporal and spatial scales.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.347-356
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• 2010

Bauxite is a main raw material for the production of alumina and aluminum hydroxide in the processing plant of KC company. It is a NORM (Naturally Occurring Radioactive Materials), and its waste, red mud, is a TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials). The purpose of the geochemical and mineralogical investigations of the bedrock and soils in and around the plant, a large NORM source, was to provide basic data for measuring the radiation dose and protecting from radioactive hazards. Soils were mixtures of minerals derived from the country rock (quartz, feldspar, mica, kaolin, gibbsite, and sepiolite) and bauxite (hematite, boehmite, and calcite) of open-air storage. Average U and Th contents of the soil samples were 4.7 ppm and 23 ppm, respectively, indicating somewhat Th anomaly. The average concentrations of radionuclides are $^{40}K$ 100~1,433 Bq/kg, $^{226}Ra$ anomaly in the red mud open-air storage. Soil external hazard indices range from 0.10 to 1.66 with an average of 0.63. Although most of the indices are below 1.0 that is a regulation value, those of 4 samples of total 41 soil samples exceed 1.0, requiring further detailed investigation.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.150-160
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• 2003

This study was carried out to assess inhibitory effects of light-blocking on water quality and phytoplankton community in Lake Juam from August to November 2000. The values of water temperature, DO, TN, $NO_3-N$, $NH_4-N$, TP, DIP, COD, SS and PH did not show clear differences between inside and outside light-blocked areas. Concentrations of Chl-a decreased -6.6${\sim}$40% (mean 14.7%) from inside of the light-blocked area by light blocking. During the study, 55 species of phytoplankton were indentified, and the dominant species were Microcystis aeruginosa, Aulacoseira granulata, Peridinium sp., Synedra spp., Oscillatoria sp., Fragilaria construens, and Trachelomonas sp. The successional pattern of dominant phytoplankton was diatoms (July)${\to}$ diatoms/cyanophytes (August-September)${\to}$cyanophytes (October)${\to}$ diatoms (October-November). The standing crop of phytoplankton showed maximum density in 22 September with $1.1{\times}10^4$cells/L, and minimum in 25 October with $4.7{\times}10^3$ cells/L. The decreasing efficiency of standing crop by light-blocking was 8${\sim}$38% (mean 19.9%). Through this study we found that blocking light seems to have a decreasing effect on the density of phytoplankton.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1026-1033
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• 2009

In this study, we computed the unit load of nonpoint source for the forest, agricultural, and urban representative region in Anseongchun watershed. In addition, Flow-weighted mean concentration (FWMC) that well represents runoff characteristics of storm water during rainfall, was calculated, and runoff pollutants loading was also examined. FWMCs of 1st rainfall, which runoff coefficient was high, had a tendency higher than those of 2nd rainfall. Based on landuse results, pollutant concentration of the non-urban such as forest and agricultural regions was higher than that of urban region. In case of BOD, runoff pollutants loading was calculated as 1,395, 1,623, 2,268kg/d in 1st rainfall for forest, agricultural, and urban regions, respectively, while runoff loading of 2nd rainfall was 503kg/d in forest), 512kg/d in agricultural, and 898kg/d in urban. By landuses, unit load of the urban as 72.7kg/ha/yr was 12 times higher than that of the agricultural as 6.5kg/ha/yr, and 8 times higher than that of the forest as 9.5kg/ha/yr.

• Ocean and Polar Research
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• v.35 no.4
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• pp.453-464
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• 2013

Heavy metals in the mangrove sediments of Chuuk and Kosrae, Federated States of Micronesia were analyzed to examine the pollution levels of heavy metals using enrichment factor (EF) and pollution load index (PLI). The mean concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb in surface mangrove sediments were 642, 125, 46.9, 149, 15.6, 0.14 and 8.55 ${\mu}g$, respectively. Kosrae mangrove sediments showed the highest concentrations of Cr and Ni while Chuuk contains more of other metals such as Cu, Zn, As, Cd and Pb. Compared to those from other mangrove regions of the world, Cr, Ni and As levels in mangrove sediments from Micronesia were at higher levels whereas Cu, Zn, Cd and Pb were at lower to median levels. In core sediment of Chuuk, metal concentrations in the upper part were higher than those in the lower part. Based on the EF and PLI values, As is evaluated as the heaviest contaminant in the surface sediment from Micronesia whilst other metals (Cr, Ni, Cu, Zn, Cd and Pb) are present at slightly lesser levels.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.539-547
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• 2002

본 연구는 풋콩 탈협기 개발을 위한 기초연구로서 풋콩 탈협기의 급치를 교환할 수 있고, 급동의 주속도와 송풍팬의 회전속도 및 공기 흡입구의 개구면적을 조절할 수 있는 실험장치를 제작하고, 급치의 종류가 풋콩의 탈협 및 손상에 미치는 영향을 분석하였다. 또한 송풍팬의 회전속도와 흡입 공기구의 개구비 변화 따른 선별 성능을 분석하였다. 그 결과를 요약하면 다음과 같다. 1 급치의 종류에 따른 풋콩의 미 탈협율은 철선 급치가 최대 1.6%, 최소 0.0%,평균 0.7%로서 가장 낮게 나타났고, 그 다음이 경도 60의 고무제 급치로서 최대 2.0%, 최소 0.0% 평균 1.1%, 경도 80의 고무제 급치는 최대 2.5%, 최소 0.0% 평균 1.7% 순으로 높아졌다. 또한 풋콩의 미탈협율은 급동 원주속도가 18m/s에서 55m/s로 증가할수록 감소하였다. 이는 급동의 원주 속도가 증가함에 따라 급치의 선단이 풋콩 꼬투리에 가하는 타격력이 증가하기 때문인 것으로 생각된다. 2. 급치의 종류에 따른 풋콩의 손상율은 경도 80의 고무제 급치는 최대 5.2%, 최소 1.3%, 평균 2.8%로서 가장 낮게 나타났고, 그 다음이 경도 60의 고무제 급치로서 최대 5.7%, 최소 2.4% 평균 3.8%, 철선 급치는 최대 6.3%, 최소 2.6% 평균 4.2% 순으로 높아졌다. 또한 풋콩의 손상율은 급동 원주속도가 증가할수록 풋콩 꼬투리의 손상율은 증가하였다. 이 또한 급등의 원주 속도가 증가함에 따라 급치의 선단이 풋콩 꼬투리에 가하는 타격력이 증가하기 때문인 것으로 생각된다. 3. 공기흡입구의 개구면적을 증가시킬수록 선별율은 높게 나타났으나 개구비가 60%이상에서는 선별율이 크게 차이가 나지 않았으며, 송풍팬의 원주속도를 높일수록 선별율은 높게 나타났다.도 콤바인이 직선구간 및 선회구간을 주행하며 수확작업이 가능함을 알 수 있었다. 그러나 곡선구간에서는 최대오차가 65.5 cm로 매우 크게 나타나, 콤바인을 무인 자율주행으로 수확하기에는 어려움이 있는 것으로 나타났다. 실제 포장은 이론적인 완전한 직선보다는 작은 굴곡이 있는 곡선의 형태가 이루어져 있으므로 주행 오차를 감소하기 위해서는 기계시각을 이용하면 보다 정밀한 조향을 이룰 수 있을 것으로 예상된다. 포장에서 DGPS 신호, 자이로 센서 등을 이용한 콤바인의 무인주행 장치는 무인 수확작업을 위한 가능성을 보여주었고, 일부의 센서의 기능을 개선하면 만족한 성능을 나타낼 수 있을 것으로 판단된다.dislocations form local defect arrangements at the grooves permitting the substantial reduction in defect density over the remainder of the interfacial area.한 최대의 감자 재배지역을 형성하였다. 제주도는 산지지형과 따뜻한 기온으로 2기작이 가능하고, 감자가공 공장설립과 교통발달에 따른 육지 시장과의 접근이 용이해졌기 때문에 남한에서 2번째로 큰 감자재배지역이 되었다.(요약 및 결론에서 발췌)그람양성균에서 효과적이었으며, 농도별 항균력시험 결과 농도가 증가할수록 비례하여 저해율도 증가함을 알 수 있었다. 첨가농도를 달리하여 미생물의 생육도를 측정한 결과, fraction II磎꼭\ulcorner경우 그람양성균에 대해 500 ppm 이상에서 뚜렷한 증식억제효과를 나타내었다.서 뚜렷한 증식억제효과를 나타내었다.min/+}$계 수컷 이형접합체 형질전환 마우스에 AIN-76A 정제사료만을 투여한 대조군은 1.40$\pm$

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5601-5609
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• 2012

The fine particulate matter($PM_{10}$) concentrations and contents were measured to check the health and environment influential factors in Pohang Iron and Steel Industrial Complex and its vicinities. In addition, the $PM_{10}$ distribution for each year and season was surveyed using the regional air quality monitoring stations. The measuring on the $PM_{10}$ inside the industrial complex showed $61.3{\pm}12.1{\mu}g/m^3$ for average concentration of $PM_{10}$ which was measured by Dongil Industry and $44.3{\pm}8.1{\mu}g/m^3$ measured by steel manufacturing industry complex management office. Both of them satisfied the environmental air quality standard. The percentage of $SO_4{^2}$, $NO_3{^-}$, $NH_4{^+}$ which are the secondary ions created out of the $PM_{10}$ in Dongil Industry and steel manufacturing industry complex management office was checked and it was revealed that the percentage of ${SO_4}^{2-}$ was high and it is considered that the pollution source related with the sulfides exist at the industrial complex. They were in order of ${SO_4}^{2-}$ > $Cl^-$ > $NO_3{^-}$ > $F^-$ > $NH_4{^+}$ in Dongil Industry and ${SO_4}^{2-}$ > $Cl^-$ > $NO_3{^-}$ > $NH_4{^+}$ > $F^-$ in steel manufacturing industry complex management office.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.1-11
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• 2021

The purpose of this study is to find out the main factors affecting air quality in urban physical space factors, and provide clues for environmental improvement. Nine monitoring stations in China's industrial city, Changchun, collected AQI concentration data from January 1, 2018 to December 31, 2019. This paper analyzes the types and distribution characteristics of urban physical facilities within a radius of 300m with the detection station as the center. The monitoring station is divided into three groups, and the difference in floating dust concentration among the three groups in different seasons is analyzed. The results show that AQI concentration is the highest in spring and winter, followed by summer, and the lowest in autumn. The place with the highest concentrations of AQI in spring are F (93.00), D (91.10), I (89.20), in summer are D (69.05), A (67.89), B (84.44), in autumn are I (62.80), G (60.84), D (53.27), D (53.27), in winter are I (95.82), H (95.60), f (94.04). Through SPSS analysis, it shows that the air index in a space with a diameter of 600 meters is related to forest land, grassland, bare land, water space, tree height, building area (average value), and building volume (average value). According to the statistical analysis results of spring and winter with the most serious pollution, forest land area (43,637m², 15.44%) and water surface area (18,736m², 6.63%) accounted for the majority, and group 1 (A, B, C) with the least average building area (448m², 0.17%) and average building volume (10,201m²) had the lowest pollution concentration. On the contrary, group 2 (D, E, F) had the highest AQI concentration, with less or no woodland (1,917m², 0.68%) and water surface area (0m², 0%), and the highest average building area (1,056m², 0.37%) and average building volume (17,470m³). It is confirmed that the characteristics of the area with the highest AQI concentration are that the more the site ratio of tree height above 12m, the smaller the site ratio of bare land, and the lower the pollution degree. On the contrary, the larger the area of bare land, the higher the pollution degree. By analyzing the characteristics of nine monitoring stations in Changchun, it can be seen that the air quality brought by the physical characteristics of urban space is closely related to the above factors.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.39-47
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• 2010

Annually, the scale of agricultural areas in Korea were being reduced as the lands were converted to other land uses. While the rate of productivity were either being maintained or increased, the pollution load from these areas were still greater in magnitude. Although the levels of pollutant concentration released in the agricultural watersheds were minimal, the combined quantities mostly from diffuse sources were high. As a consequence, the Ministry of Environment (MOE) in Korea adopted the use of free water surface (FWS) flow constructed wetlands to reduce the pollutant loadings emitted from agricultural watersheds for the improvement of water quality and protection of aquatic ecosystems. In this study, a constructed wetland treating stream water in an agricultural watershed was monitored since April 2009 subsequent to its completion in December 2008. Satisfactory performance was achieved for TSS, BOD and TP with 26%, 28% and 39% pollutant removal rates, respectively. In addition, the effluent water quality was improved and achieved compliance the national water quality criteria. Results of this study can be useful to establish design parameters and employ proper removal techniques of similar natural treatment systems for future implementation in the country.

• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.97-101
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• 1997

During the period of March 1995 to December 1995, tritium concentrations of tritiated water vapor (HTO) and tritiated hydrogen (HT) in the atmosphere in Taejon were measured to evaluate present background levels of tritium in the atmosphere. Air samples were collected continuously for three weeks with a sampling system for tritium in the atmosphere and were analyzed by a liquid scintillation counting system. The range of the atmospheric HTO concentrations was 3.2-36 mBq $m^{-3}$ with a mean value of 16.2 mBq $m^{-3}$. The atmospheric HTO concentrations were the highest in summer and the lowest in winter. This trend was similar to the variation of atmospheric absolute humidity. The specific activities of tritium in atmospheric water vapor in Taejon ranged from 0.62 Bq $L^{-1}$ to 3.82 Bq $L^{-1}$ with a mean value of 2.04 Bq $L^{-1}$. The atmospheric HT concentrations were in the range of 35.7 mBq $m^{-3}$ to 48.9 mBq $m^{-3}$ with a mean value of 41.1 mBq $m^{-3}$.