• Title/Summary/Keyword: Low area

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Relationship between Thermal Low and Long-Range Transport of Air Pollutants (대기오염물질의 장거리 수송과 열적저기압의 관계)

  • 이화운;김유근;김해동;정우식;현명숙
    • Journal of Environmental Science International
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    • v.10 no.2
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    • pp.143-151
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    • 2001
  • The atmospheric conditions and the transport mechanism of long-range transport of air pollutants from coastal area to inland area were investigated using regular meteorological data and air pollution data obtatined from the southeastern area of Korea. Daytime temperature over the inland area(Taegu) was higher than that over the coastal area(Pusan) and the temperature difference of about 5~6$^{\circ}C$ when the thermal low most fully developed and the sea level pressure over Taegu was lower than that over Pusan by about 4~5hPa at that time. Therefore this low pressure appeared to the thermally induced low. Air mass polluted from the coastal area during the morning period was transported inland area, at first by the sea breeze and by the large scale wind system toward the thermal low generated in the mountainous inland region. This was explained by the fact that the concentration of air pollutants over Taegu increased throughtout the late afternoon.

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금산지역 토양별 화학적 특성과 주요 용존성분

  • 송석환;이용규
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.09a
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    • pp.195-199
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    • 2002
  • This study is for know chemistry of the representative soils from Keumsan, its relationships with dissolved compositions, and its absorption relationships within the flora. It has been done for two comparisons: 1) phyllite, shale and granite(PSG), and 2) granite and coal bearing shale(GC). Among the soil leachate of the PSG, cations are mainly low in the phyllite area while anions are mainly low in the granite area. In the soil compositions, Ca and Mg of the beans are high and Na is high in the granite area while Ca and Na of the perilla are high in the granite area and Mg is high in the phyllite area. In th both species, Na for the granite area and Mg for the phyllite area are high while Ca for the shale area is low. Among the flora, shale area shows low Ca and Mg contents while granite area shows slightly high Na contents, regardless the species. Compared with beans, perilla is low in the Mg and high in the Na contents. These relationships show that the contents of the soil leachate do not reflect absorption within the flora. Among the soil leachate of the GC, shale area is high in the most of the elements. Especially, SO$_4$ is over 15 times high In the phyllite area. In the soil, granite area shows high Ca, Na and low Mg contents. In the flora, the Miscanthus sinensis shows high Ca and Mg contents in the granite area while the Artemisia vulgaris shows high Ca, Ca and Mg contents in the shale area. These relationships for contents of the flora and soil leachate suggest that the flora has a different absorption according different species.

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A Study of Optimal Water Supply Planning in Mountainous Area (산지유역에서의 최적용수공급방안에 관한 연구)

  • Kim, Ji-Hak;Park, Ki-Bum
    • Journal of Environmental Science International
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    • v.15 no.10
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    • pp.967-973
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    • 2006
  • In this study used tank model and specific discharge to calculate low-flow of mountain basin and supply data that need in water resources plan. Low-flow is calculated byspecific discharge and area ratio method as resulted that calculate storage of low-flow by tank model was construed that showd all similar aspect. In judged to help in water resources plan establishment calculating low-flow using model to supplement uncertainty of observed data in that calculate of low-flow ungaged mountain area. It shows by economical and realistic plan until 12 years after development that run parallel and use economic performance analysis result valley flow and groundwater. But wide area water services and Chungju dam since 12 years onward was expose that is economic.

A Study on the Characteristic Micro-Climate in the City using Computerized Fluid Analysis and Actual Measurement (전산유체해석과 실측을 이용한 도심내 미기후 특성에 대한 연구)

  • You, Jang-Youl;Park, Min-Woo
    • Journal of Korean Association for Spatial Structures
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    • v.23 no.1
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    • pp.35-43
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    • 2023
  • Microclimate analysis was conducted through actual measurement according to land use status in urban, and CFD analysis was conducted to analyze and predict the microclimate characteristics of urban, and compared and analyzed with the actual measurement results. It was measured in high-rise areas and parks, and the temperature of the park area was 0.4 to 0.6℃ lower, and the relative humidity was 1.0 to 3.0% higher. The correlation coefficient was obtained by comparing the results of the computational fluid analysis with the results of the computational fluid analysis at the actual location located within the CFD analysis area for validation. The seasonal correlation coefficients are all higher than 0.8, so it is judged that they can be applied to microclimate analysis in urban area. The computational fluid analysis was divided into three areas (low-rise, low and high-rise, and high-rise) centered on the A2 point. On average, the low-rise area was 0.1 to 0.4% higher than the high-rise area. In the low and high-rise area and high-rise area, the pith of buildings are wide, so the airflow is smooth, so it is judged that the temperature is relatively low.

A Research on the Youth Facilities Management with Importance-Performance Analysis ((중요도-성취도)분석에 의한 청소년수련시설 운영실태 조사연구)

  • 구태익
    • Journal of the Korean Institute of Landscape Architecture
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    • v.23 no.2
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    • pp.137-147
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    • 1995
  • This research is a preliminary study to improve the criteria of youth facilities which regulated in Youth Fundamental Act, with the method of Importance-Performance Analysis on youth facilities management. Evaluation inquiry had been made, and were collected from the youth facility managers who attended The Korean Youth Facility Managers' Seminar held on 24th Nov. 1994 at Pakdaljae Youth Center. The results are as follows; 1. Keep Up the Good Work : indoor facilities in community area, and outdoor facilities and accommodations in natural area are resulted in high in Importance and. Performance. They need to be operated constantly. 2. Concentrate Here : Counselling room, hobby room and outdoor meeting places in community area, and care room in natural area are perceived high in Importance but low in Performance. They need to provide proper leaders and equipment. 3. Low Priority : Care room, forest and outdoor facilities in community area, arid forest and folk playground in natural area are low in both Importance and Performance. So, it is considered that they are not necessary ones in both areas, but some outdoor facilities are so essential in natural area that they need to be provided properly. 4 Possible Overkill : Courtyard and library in community area, and outdoor facilities in natural area are low in Importance but high in Performance. They need to improve their importance through the development of applicable activity programs.

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Design of a Low-Power and Low-Area EEPROM IP of 256 Bits for an UHF RFID Tag Chip (UHF RFID 태그 칩용 저전력, 저면적 256b EEPROM IP 설계)

  • Kang, Min-Cheol;Lee, Jae-Hyung;Kim, Tae-Hoon;Jang, Ji-Hye;Ha, Pan-Bong;Kim, Young-Hee
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.671-674
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    • 2009
  • We design a low-power and low-area asynchronous EEPROM of 256 bits used in a passive UHF RFID tag chip. For a low-power solution, we use a supply voltage of 1.8V and design a Dickson charge pump using N-type Schottky diodes with a low-voltage characteristic. And we use an asynchronous interface and a separate I/O method for a low-area solution of the peripheral circuit of the designed EEPROM. And we design a Dickson charge pump using N-type Schottky diodes to reduce an area of DC-DC converter. The layout area of the designed EEPROM of 256 bits with an array of 16 rows and 16 columns using $0.18{\mu}m$ EEPROM process is $311.66{\times}490.59{\mu}m^2$.

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Enzymatic Synthesis of Low-trans Fats Containing Conjugated Linoleic Acids and Their Physicochemical Characteristics (Conjugated Linoleic Acid(CLA)를 함유한 기능성 저트랜스 유지의 효소적 합성 및 이화학적 특성 연구)

  • Nam, Ha-Young;Lee, Ki-Teak
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.37 no.6
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    • pp.752-760
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    • 2008
  • Scale-up production of low-trans fat containing conjugated linoleic acid (CLA-TFO) was performed through lipase-catalyzed synthesis. Blend of fully hydrogenated soybean oil, olive oil containing conjugated linoleic acid and palm oil with 1:2:7 ratio was interesterified through Lipozyme RM IM in the 1 L-batch type reactor at $65^{\circ}C$ for 12 hrs, and the physicochemical and melting properties of CLA-TFO were compared with conventional (high trans fat) or commercial low-trans fat shortening. The trans fatty acids content in the conventional shortening (48.8 area%) was much higher than that of low-trans shortening (0.4 area%) and CLA-TFO (0.3 area%+CLA; 7.6 area%). Acid, saponification and iodine values of CLA-TFO were 0.4, 173.9 and 59.0, respectively. Their ${\alpha}$-, ${\gamma}$-tocopherol contents showed 4.7, 1.0 mg/100 g. Differences were observed in the solid fat contents (SFC), melting point of the conventional or low-trans fat and CLA-TFO. Each SFC of conventional, low-trans fat and CLA-TFO was 32.0, 29.3 and 30.4% with melting point of 38.5, 43.0 and $39.5^{\circ}C$ at $35^{\circ}C$, respectively. In texture profile analysis, hardness of conventional, low-trans fat and CLA-TFO was 111.7, 75.2 and 63.8 g.

Damping of Inter-Area Low Frequency Oscillation Using an Adaptive Wide-Area Damping Controller

  • Yao, Wei;Jiang, L.;Fang, Jiakun;Wen, Jinyu;Wang, Shaorong
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.27-36
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    • 2014
  • This paper presents an adaptive wide-area damping controller (WADC) based on generalized predictive control (GPC) and model identification for damping the inter-area low frequency oscillations in large-scale inter-connected power system. A recursive least-squares algorithm (RLSA) with a varying forgetting factor is applied to identify online the reduced-order linearlized model which contains dominant inter-area low frequency oscillations. Based on this linearlized model, the generalized predictive control scheme considering control output constraints is employed to obtain the optimal control signal in each sampling interval. Case studies are undertaken on a two-area four-machine power system and the New England 10-machine 39-bus power system, respectively. Simulation results show that the proposed adaptive WADC not only can damp the inter-area oscillations effectively under a wide range of operation conditions and different disturbances, but also has better robustness against to the time delay existing in the remote signals. The comparison studies with the conventional lead-lag WADC are also provided.

A Study on Land Surface Temperature Changes in Redevelopment Area Using Landsat Satellite Images : Focusing on Godeok-dong and Dunchon-dong in Gangdong-gu, Seoul (Landsat 위성영상을 활용한 재건축 지역의 지표 온도 변화에 관한 연구 : 서울특별시 강동구의 고덕동과 둔촌동을 중심으로)

  • Jihoon HAN;Chul SON
    • Journal of the Korean Association of Geographic Information Studies
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    • v.26 no.2
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    • pp.42-54
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    • 2023
  • The population is concentrated in the metropolitan areas in Korea, and low-density residential areas are transforming into high density residential areas through redevelopment to meet this demand. However, large-scale redevelopment in a short period of time has a negative impact on the urban climate, such as generating a heat island effect due to the reduction of urban green areas. In this study, the change in surface temperature from 2013 to 2022 in the redevelpment areas of Godeok-dong and Dunchon-dong, Gangdong-gu, Seoul, was analyzed using Landsat 8 satellite images. In the Godeok-dong area, the difference in surface temperature was analyzed for the target redevelopment area, forest area, mixed forest and urban area, and low density residential area. In the Dunchon-dong area, the difference in surface temperature was analyzed for the target redevelopment area, forest area, and low density residential area. The difference in surface temperature was analyzed through multiple regression analysis conducted yearly over the three different stages in redevelopment period. The results from the multiple regression analysis show that in both areas, the land surface temperature of target redevelopment area was higher than that of the forest area and lower than low density residential area. It can be seen that these results occurred because the low-density residential area in Godeok-dong and Dunchon-dong had a lower green area ratio and a higher building-to-land ratio than the target redevelopment area. The results of this study suggest that even if low-density residential areas are transforming into high-density areas, adjusting the management of green areas and building-to-land ratio can contribute to lessen urban heat island effect.

The Effects of low concentrative ${\beta}-APN$ on periodontal tissue of Rat (저농도의 ${\beta}-aminoproprionitrile$이 백서 치주조직에 미치는 영향)

  • Lee, Jae-Mok
    • Journal of Periodontal and Implant Science
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    • v.26 no.4
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    • pp.859-872
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    • 1996
  • The purpose of this study was to evaluate the effect of low concentrative ${\beta}-APN$ on the periodontal ligament and relationship between lathyrintic bodies and osteoclast cells near the by alveolar bone. Mandibles including teeth and periodontiums of 24 Sprague-Dawley rat was used. ${\beta}-APN$ 0.2g/kg/day soluted in mineral water was administrated for 5 days before sacrifice in experimental group. 3 rats on each day was sacrificed on 1, 3, 7, 11 days after stop administration ${\beta}-APN$. Histologic examination and the activity of osteoclasts by tartrate resistant acid phosphatase was observed. The results were as follows : 1. In experimental group, the The small foci of lathyrintic bodies surrounded by palisading fibroblasts were seen obviously on 1, 3 days and decreased after 7 days. On 11 days, fibroblasts of periodontal ligament similar to control group. 2. The lathyrintic bodies were seen in the middle zone of periodontal ligament of pressured area like furcation area, alveolar crest, bone resorption area than tensioned area of apposition area. 3. In experimental group of 1, 3 days, lathyrintic bodies were much seen in the area that osteoclasts was much distributed area. After 7 days, experimental group was seen the control group. In conclusion, rathyrintic bodies were formed by low concentrative ${\beta}-APN$ chiefly on the pressured area like furcation area, alveolar crest, bone resorption area than tensioned area of apposition side in periodontal tissue and concerned with osteoclast cells.

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