• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1215-1223
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• 2020

Recently, the number of natural disasters caused by inclement weather conditions such as localized heavy rainfall, Typhoon, etc. is increasing in Korea, which requires relevant prevention and water management measures. Rain gauges installed on the ground have strengths in continuously·directly measures ground precipitation but cannot provide accurate information on spatial precipitation distribution in the areas without the rain gauges. The present research has designed and developed an electromagnetic-based multi-purpose precipitation gauge(EWRG, Electromagnetic Wave Rain Gauge) that can measure rainfall at the real time, by overcoming spatial representativeness. In this paper, we propose an FPGA-based signal processing design method for EWRG. The signal processing of the EWRG was largely designed by calculating the ADC and DDC of the LFM waveform, pulse compression, correlation coefficient and estimating the precipitation parameter. In this study, the LFM waveform and pulse compressed signal were theoretically analyzed.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E2
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• pp.47-56
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• 2007

Among all the nitrogen species present in the atmosphere, ammonia forms a considerable portion along with the nitrogen oxides. The major sources of atmospheric ammonia are animal feedlot operations including emission from excreta of domestic animals and agricultural activities, followed by emission from synthetic fertilizers, biomass burning and to some lesser extent, fossil fuel combustion. Ammonia emission factor, expressed as the weight of ammonia per unit weight, volume, or duration of the activity emitting it, is generally used in developing emission estimates for emission inventories. The factors determining ammonia loss from soil or from manures are the temperature, pH, humidity, precipitation and the velocity of wind above it.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.64-71
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• 2007

In this study daily flow data is constructed from 8-day intervals flow data which has been measured by Nakdong River Water Environmental Laboratory. TANK model is used to expand 8-day intervals flow data into daily flow data. Using the Sequential quadratic programing, TANK model is auto-calibrated with daily precipitation and 8-day interval flow data. Generated and measured daily surface flow, ground water flow data and ground water recharge are shown to be in a good agreement. From this result, it is thought that this method has the potential to provide daily flow data for calibrating an watershed model such as SWAT.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.181-187
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• 2000

Fatigue tests under acid fog environment were carried out to investigate the effect of acid fog on the corrosion fatigue strength of SM55C in comparison with distilled water. Main results obtained are as follows. The fatigue strength of SM55C under acid fog environment are remarkably decreased as compared with that of distilled water specimen. The corrosive effect of acid fog on fatigue strength are more serious under low stress amplitude level than under high stress amplitude level, and this leads to continuous reduction of fatigue strength. Under acid fog environment in early stage of crack growth. because the corrosive components dissolve the crack face offensively. the unstable fracture surface appears. But, the stable corrosion precipitation and products layer are formed on the fracture surface in accordance with the time pass.

• Journal of Korea Water Resources Association
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• v.53 no.10
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• pp.903-915
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• 2020

Long-term high-resolution hydro-meteorological data has been recognized as an essential element in establishing the water resources plan. The increasing demand for spatial precipitation in various areas such as climate, hydrology, geography, ecology, and environment is apparent. However, potential limitations of the existing area-weighted and numerical interpolation methods for interpolating precipitation in high altitude areas remains less explored. The proposed PRISM (Precipitation-Elevation Regressions on Independent Slopes Model) model can produce gridded precipitation that can adequately consider topographic characteristics (e.g., slope and altitude), which are not substantially included in the existing interpolation techniques. In this study, the PRISM model was optimized with SCEM-UA (Shuffled Complex Evolution Metropolis-University of Arizona) to produce daily gridded precipitation. As a result, the minimum impact radius was calculated 9.10 km and the maximum 34.99 km. The altitude of coastal weighted was 681.03 m, the minimum and maximum distances from coastal were 9.85 km and 38.05 km. The distance weighting factor was calculated to be about 0.87, confirming that the PRISM result was very sensitive to distance. The results showed that the proposed PRISM model could reproduce the observed statistical properties reasonably well.

• Atmosphere
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• v.16 no.3
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• pp.247-257
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• 2006

The Yeong-dong heavy snowfall forecast supporting system has been developed during the last several years. In order to construct the conceptual model, we have examined the characteristics of heavy snowfalls in the Yeong-dong region classified into three precipitation patterns. This system is divided into two parts: forecast and observation. The main purpose of the forecast part is to produce value-added data and to display the geography based features reprocessing the numerical model results associated with a heavy snowfall. The forecast part consists of four submenus: synoptic fields, regional fields, precipitation and snowfall, and verification. Each offers guidance tips and data related with the prediction of heavy snowfalls, which helps weather forecasters understand better their meteorological conditions. The observation portion shows data of wind profiler and snow monitoring for application to nowcasting. The heavy snowfall forecast supporting system was applied and tested to the heavy snowfall event on 28 February 2006. In the beginning stage, this event showed the characteristics of warm precipitation pattern in the wind and surface pressure fields. However, we expected later on the weak warm precipitation pattern because the center of low pressure passing through the Straits of Korea was becoming weak. It was appeared that Gangwon Short Range Prediction System simulated a small amount of precipitation in the Yeong-dong region and this result generally agrees with the observations.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.1
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• pp.64-72
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• 1994

Recently, the acid precipitation, composed primarily of dilute $H_2$S $O_4$, HN $O_3$and originating from the burning of fossil fules, has become one of the major environmental problems. This study was carried out to investigate the chemical features of precipitation at Sobaek-san Meteorological Observation Station(mean sea level; 1,340m, 36$^{\circ}$56’N, 128$^{\circ}$27' E)from May 1991 to December 1993. The major Point in this study divided the whole wind directions into two parts. And, the two parts are the north- westerly wind case and south-easterly wind case. The concentration of anions and cations in precipitation were measured by ion chromatography(Dionex 4000i). The volumn weighted mean pH and conductivity values of the whole precipitation period were 5.26, 14.3$mutextrm{s}$/cm, respectively. The order and frequency rate of the major anions concentration in the north- westerly and south easterly wind case were S $O_4$$^{2-}$(49.3%) ＞ N $O_3$$^{[-10]}$ (23.9%) ＞ C $l^{[-10]}$ (14.8%) ＞ $F^{[-10]}$ (12.0%) and S $O_4$$^{2-}$(61.1% ) ＞ N $O_3$$^{[-10]}$ (21.5%) ＞ C $l^{[-10]}$ (13.5%) ＞ F/sip -/(4.0%), respectively. The order and frequency rate of the major cations concentration in the north-westerly and south- easterly wind case were $Ca^{2+}$(49.3%) > N $H_4$$^{+}$(24.2%) >N $a^{+}$(22.4%) ＞M $g^{2+}$(14.9%) > $K^{+}$(3.8%) and N $H_4$$^{+}$(4:3.8%) $Ca^{2+}$(28.6%) ＞ N $a^{+}$(16.8%) > $K^{+}$(6.3%) > $Mg^{2+}$(4.5%), respectively. The larger anions and cations concentration values than others were S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ and $Ca^{2+}$, N $H_4$$^{+}$, respectively. The correlation coefficient between pH value and ion concentrations for the north-westerly and south-easterly wind case was shown less than 0.5 except for Ca/.sup 2+/ in the statistical analysis SPSS. But the correlation coefficient for the all wind case between sulfate and cations was shown high correlation above 0.6.correlation above 0.6.

• Korean Journal of Environment and Ecology
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• v.12 no.2
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• pp.131-137
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• 1998

This study was performed to investigate tree injury with air pollution and acid precipitation in industrial area and rural area. This study analyzed the ion properties of pollutant precipitated in the forest of Ulsan ＆ Onsan area and correlation between S $O_2$concentration in air and the degree of forest decline. pH of industrial area was lower than that of rural area and electrical conductivity and pH had a negative correlation(r=-.7861$^{**}$). Correlation of cation and anion(especially S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ ) in precipitation and S $O_2$in air was higher in industrial area. In seasonal change, winter and spring were higher. In the analysis of correlation between forest decline and variables of precipitation properties, correlation coefficient was higher by following order: S $O_{4}$$^{2-}$>pH>EC>N $O_{3}$$^{[-10]}$ >S $O_{2}$$^{2-}$>C $l^{[-10]}$ . Regression formula by computation was Y = 5.1007-0.7811 $X_2$(pH) +0.0253 $X_{5}$ (S $O_{4}$$^{2-}$) +0.0275 $X_{6}$ (N $O_{3}$$^{[-10]}$ ). In considering the result of this study, it was predicted that air pollution and acid rain would affect soil acidification and forest decline continuously.y.

• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.21-31
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• 1998

A study on the acid leaching and precipitation has been conducted to remove arsenic from the closed-mine tailings. HCI and H$_2$SO$_4$were used as the leach liquor of arsenic and the tailing obtained from the Da-Duck Mine, which was already closed several decades ago, was also used as the source of arsenic. The effect of the concentration of acid, leaching time and the slurry density on the leaching efficiency of arsenic has been examined. In addition, pH controls and the addition of sodium sulfide were also attempted to remove the arsenic compound as the precipitation from the leachate. After 1 hr leaching by HCI, 40 to 86% of arsenic was leached out depending on the concentration of acid or the slurry density while 47 to 77% of it was leached out by $H_2$$SO_4$. The leaching of arsenic by both acids was almost accomplished within 10 min. and after that only a slight increase in leaching efficiency was observed with leaching time. When the leach liquor was used repeatedly for the leaching of arsenic, the concentration of arsenic in the leach liquor was found to increase continuously although the leaching efficiency was diminished. As far as the precipitation of arsenic in the leachate was concerned, more than 99% of arsenic could be precipitated through the addition of sodium sulfide as the precipitator while the pH controls resulted in the precipitation of up to 84%.

• Journal of the Mineralogical Society of Korea
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• v.31 no.2
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• pp.75-86
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• 2018

This study analyzed precipitation environment, heavy metal concentration, mineral composition, and spectral characteristics associated with heavy metal concentration and mineral composition for the reddish brown precipitates occurred in the drainage of Dogye mining station. The pH of the reddish brown precipitates ranges from 7.59 to 7.94 resulting neutral. XRF analysis reveals that the precipitates has high Fe concentration, and contaminated with Ni, Cu, and Zn. Dolomite, calcite, goethite, magnetite, kaolinite, pyrophyllite, quartz and aluminum isopropoxide were identified based on XRD analysis. As a result of spectral analysis associated with heavy metal contamination, visible reflectance increases and infrared reflectance decreases with a increase in heavy metal concentration. The spectral characteristics of the reddish brown precipitates is turned out to be manifested by goethite, magnetite, kaolinite, pyrophyllite and aluminum isopropoxide.