• 환경영향평가
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• 제14권3호
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• pp.135-145
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• 2005

This study was conducted to investigate the characteristics of meteorological environment variation before and after construction of Nak-dong river estuary barrage. We used meteorological data(air temperature, precipitation, relative humidity, visibility, wind) at Gimhae airport meteorological station. The construction of river estuary barrage can change climate at the neighboring districts and influence human's health and vegetable. The construction of Nakdong river estuary barrage brought rise of temperature, decrease of relative humidity and increase of poor visibility frequency.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.798-800
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• 2003

The time shift processing of ground measured surface temperature with the meteorological variables has no evaluated function. We introduce new evaluating function. To use this evaluating function, the algorithm of time-shift processing will be able to be reliable and get error-bar for all moving measured point's data. We will finally obtain the area averaged surface temperature by land observation.

• 한국환경과학회지
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• 제26권8호
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• pp.913-925
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• 2017

Phytoplankton populations were examined at three sites in Lake Cheongpyeong, South Korea from March 2008 to December 2016, including measurement of phytoplankton communities and their dominant species, abundance and environmental factors. The annual average ranges of water temperature, dissolved oxygen and conductivity were $15.2-18.8^{\circ}C$, 10.3-12.2 mg/L, $86-140{\mu}S/cm$, respectively, with similar values at all studied sites. The highest phytoplankton cell density was observed in spring and fall, and it subsequently decreased rapidly during heavy rainfall. Diatoms were dominant in spring (mainly Stephanodiscus hantzschii, Asterionella formosa) and fall (mainly Aulacoseira granulata), while greenalgae and cyanobacteria had high appearance in early-summer and summer, respectively, indicating that water temperature is the most important factor influencing their growth. Stephanodiscus hantzschii and Asterionella formosa frequently occurred at low water temperature ($4.5-15.0^{\circ}C$ and $5.4-21.6^{\circ}C$, respectively) while Aulacoseira granulata and Anabaena spp. were favored by high water temperature (8.6-28.4 and $14.9-26.2^{\circ}C$, respectively) and phosphorus. Additionally, Fragilaria crotonensis occurred at low nutrient conditions. Rhodomonas spp. frequently appeared year-round.

• 동력기계공학회지
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• 제7권2호
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• pp.56-60
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• 2003

Recently the plastic fuel tube is usually used to reduce production cost and weight in automobiles. These days, material used to plastic fuel tube is the polyamide12. The fuel tube is made of the PA12. Post deformation of the tube has been changed by environmental temperature. So, it is important to prevent post deformation. The experiment is performed to investigate post deformation of the tube produced by each bending process. In this study, the results we obtained are used to bending process system for post deformation as the environmental temperature of the tube. It turned out that the method of steam heating and air cooling was shown less deformation than other methods.

• 한국환경과학회지
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• 제18권10호
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• pp.1171-1179
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• 2009

The solitary ascidian, Halocynthia aurantium, which is commonly called the sea peach because of its coloration and general shape, is a valuable organism of benthic marine population in the northern region of the East Sea, Korea. It is seldom found at a depth of less than 10 meters and the sea peach is frequently observed in large populations between 20 and 100 meters. It appears to prefer attachment to vertical rocks faces and artificial cement blocks exposed to the currents. Mass mortality and reduction of resources in sea peach, H. aurantium, were occurred in the benthic area of the northern region of the East Sea because of the rapid fluctuation of environmental factors such as temperature and salinity due to mass rainfall in summer and going up north of a strong warm current in winter. Therefore, we examined the effects of temperature and salinity on embryonic development of fertilized eggs, tadpole larva to metamorphosis, and attachment to siphon development. Laboratory-raised larvae were studied using a two-factorial experimental design with four levels of temperature(8, 12, 16 and $20^{\circ}C$) and four levels of salinity(20, 25, 30 and 34 psu). The ascidian larvae of H. aurantium survived environmental conditions between temperature of $8{\sim}20^{\circ}C$ and salinity of 25~34 psu and exhibited positive growth at $8{\sim}16^{\circ}C$ and 30~34 psu. Fertilized eggs have not developed at lower salinity of 20 psu irrespective of temperature range tested and have showed an abnormal development at the salinity of 25 psu between higher temperatures of 20 and $24^{\circ}C$. This result suggests that temperature increase and salinity reduction depending on environmental fluctuation may have significant impacts on population variation of H. aurantium in the northern region of the East Sea.

• 한국환경과학회지
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• 제15권6호
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• pp.579-586
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• 2006

The purposes of this paper were to monitor the temperature rising courses and spark discharge of the modified granular activated carbon (GAC) by microwave (MW) irradiation and to evaluate absorption of benzene. The GAC coated on $SiO_2$, boron, talc, ferrite was named as the modified GAC. Thermal and spark discharge measurement of virgin GAC and modifed GAC has been carried out using a MW device operating at 2450 MHz under various energy conditions. The results of this paper as follows. First, the modified GAC is more efficient than the virgin GAC in temperature control. Temperature gradient of the modified GAC is more lower than that of virgin GAC. The temperature gradient of GAC was observed in the following order : virgin GAC, Mn-Zn ferrite/GAC, Ni-Zn ferrite,/GAC, $SiO_2/GAC$, Boron/GAC, Talc/GAC. Second, the spark discharge of the modified GAC was diminished, compared with that of virgin GAC. Because of its excellent electrical insulating properties, the coating material prevents the spark discharge. Finally, the benzene adsorption capacity of the modified GAC decreased due to diminishing of adsorption site by the coating material. Considering the temperature gradient and spark discharge of GAC, the GAC coated $SiO_2$ would be appropriate absorbent under irradiation of MW.

• 환경위생공학
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• 제18권3호통권49호
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• pp.48-58
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• 2003

To obtain the preliminary design data for combustion of paper sludges, decomposition characteristics and combustion kinetics of paper sludges reactor have been determined in a TGA reactor. Also, the combustion characteristics of paper sludges have been determined in a fluidized bed reactor. The data obtained from the TGA reactor indicate that dewatering of paper sludge is terminated at temperature below 130${\circ}$C. With heating rate of 20${\circ}$C/min, combustion is terminated at temperature below 340${\circ}$C .The combustion rate is found to be first order with respect to temperature and oxygen concentration. Activation energies for paper wastes are found to be 570, 700, 2600, 4600 Kcal/mole, respectively. The calcination conversions were investigated with the operating temperature and residence time. In this investigation, it was found that calcination conversion was affected by the operating temperature and residence time. The optimum conditions of operating temperature and mean residence time were 850${\circ}$C and 6 minutes of respectively.

• Asian Journal of Atmospheric Environment
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• 제12권3호
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• pp.244-254
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• 2018

Ulaanbaatar, the capital of Mongolia, is subject to high levels of atmospheric pollution during winter, which severely threatens the health of the population. By analyzing surface meteorological data, ground-based LIDAR data, and radiosonde data collected from 2008 to 2016, we studied seasonal variations in particulate matter (PM) concentration, visibility, relative humidity, temperature inversion layer thickness, and temperature inversion intensity. PM concentrations started to exceed the 24-h average standard ($50{\mu}g/m^3$) in mid-October and peaked from December to January. Visibility showed a significant negative correlation with PM concentration. Relative humidity was within the range of 60-80% when there were high PM concentrations. Both temperature inversion layer thickness and intensity reached maxima in January and showed similar seasonal variations with respect to PM concentration. The monthly average temperature inversion intensity showed a strong positive correlation with the monthly average $PM_{2.5}$ concentration. Furthermore, the temperature inversion layer thickness exceeded 500 m in midwinter and overlaid the weak mixed layer during daytime. Radiative cooling enhanced by the basin-like terrain led to a stable urban atmosphere, which strengthened particulate air pollution.

• 한국환경과학회지
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• 제20권8호
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• pp.1049-1059
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• 2011

This paper examines the effects of the partial solar eclipse of 22 July 2009 across the Korean peninsular on surface temperature and ozone concentrations in over the Busan metropolitan region (BMR). The observed data in the BMR demonstrated that the solar eclipse phenomenon clearly affects the surface ozone concentration as well as the air temperature. The decrease in temperature ranging from 1.2 to $5.4^{\circ}C$ was observed at 11 meteorological sites during the eclipse as a consequence of the solar radiation decrease. A large temperature drop exceeding $4^{\circ}C$ was observed at most area (8 sites) of the BMR. Significant ozone drop (18~29 ppb) was also observed during the eclipse mainly due to the decreased efficiency of the photochemical ozone formation. The ozone concentration started to decrease at approximately 1 to 2 hours after the event and reached its minimum value for a half hour to 2 hours after maximum eclipse. The rate of ozone fall ranged between 0.18 and 0.49 ppb/min. The comparison between ozone measurements and the expected values derived from the fitted curve analysis showed that the maximum drop in ozone concentrations occurred at noon or 1 PM and was pronounced at industrial areas.

• 한국환경과학회지
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• 제29권1호
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• pp.45-54
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• 2020

High-resolution meteorological simulations were conducted using a Weather Research and Forecasting (WRF) model with an Urban Canopy Model (UCM) in the Ulsan Metropolitan Region (UMR) where large-scale industrial facilities are located on the coast. We improved the land cover input data for the WRF-UCM by reclassifying the default urban category into four detailed areas (low and high-density residential areas, commercial areas, and industrial areas) using subdivided data (class 3) of the Environmental and Geographical Information System (EGIS). The urban area accounted for about 12% of the total UMR and the largest proportion (47.4%) was in the industrial area. Results from the WRF-UCM simulation in a summer episode with high temperatures showed that the modeled temperatures agreed greatly with the observations. Comparison with a standard WRF simulation (WRF-BASE) indicated that the temporal and spatial variations in surface air temperature in the UMR were properly captured. Specifically, the WRF-UCM reproduced daily maximum and nighttime variations in air temperature very well, indicating that our model can improve the accuracy of temperature simulation for a summer heatwave. However, the WRF-UCM somewhat overestimated wind speed in the UMR largely due to an increased air temperature gradient between land and sea.