• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.119-128
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• 2004

The nitrate concentrations in PM$_{2.5}$ and TSP measured at Gosan, Jeju Island, Korea, between March 1998 and February 2002, are discussed. Especially, the characteristics of high nitrate concentration days were analyzed. High nitrate concentration cases in PM$_{2.5}$ were highly correlated with anthropogenic species such as NH$_4$$^{[-10]}$ , and high nitrate concentration cases in TSP were highly correlated with crustal species such as nss-Ca$^{2+}$ and nss -Mg$^{2+}$ Backward trajectory analysis results show the cases of high correlation between nitrate and anthropogenic species occurred when the air parcels moved from China, and the cases of high correlation between nitrate and crustal species occurred when the air parcels moved from Mongolia. Also, high nitrate concentration cases occurred most often in spring (65%) when the air parcels moved from Mongolia and China.ina.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.966-973
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• 2005

The stress concentration ratio in accordance with area replacement ratios were considered as core elements of design. However, the stress concentration ratio will be vary depends on progress of consolidation in clay ground. And, since it is not sure to know the affecting factors accurately, the value is decided based on field experiences. To use SCP method more effective and correspond to soil improvement, the decision on proper area replacement ratio through the exact stress concentration ratio is very important. Accordingly, a numerical analysis on influence of various factors that needed to make rational designing guide for decision of proper area replacement ratio to stress concentration ratio was executed in this study.

• Journal of Environmental Science International
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• v.22 no.8
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• pp.1043-1052
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• 2013

This study was conducted to investigate the correlations between the $PM_{10}$ concentration trend and meteorological elements in the Gimhae region and analyze the transportation routes of air pollutants through back-trajectory analysis. Among the air quality measuring stations in the Gimhae regions, the $PM_{10}$ concentration of the Sambangdong station was higher than that of the Dongsangdong station. Also, an examination of the relationships between $PM_{10}$ concentration and meteorological elements showed that the greater the number of yellow dust occurrence days was and the lower the temperature and precipitation were, the higher the $PM_{10}$ concentration appeared. Furthermore, a cluster analysis through the HYSPLIT model showed that there were 4 clusters of trajectories that flowed into the Gimhae region and most of them originated in China. The meteorological characteristics of the four clusters were analyzed and they were similar to those of the air masses that influence South Korea. These analyses found that meteorological conditions affect the $PM_{10}$ concentration.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.53-59
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• 2010

A fatigue damage caused by cyclic load is considered as one of the important failure mechanisms that threaten the integrity of structures and components in a nuclear power plant. In ASME code section III NB, the fatigue analysis procedure and standard S-N curves for the class 1 components are described and these criteria should be met at the design step of components. As the current ASME S-N curves are based on the very conservative assumptions such as a local stress concentration effect, immoderate transient frequencies and a constant Young's modulus, however, they can not precisely address the fatigue behavior of components. In order to find out the technical solution for these problems, a number of researches and discussion have been carried out continuously at home and abroad over the decades. In this study, detailed fatigue analyses for DVI nozzle with various mesh density of finite elements were performed to evaluate effect of stress concentration factors on the fatigue analysis procedure and the excessive conservatism of stress concentration factors are confirmed through the analysis results.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.245-255
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• 2020

Objective: The present study analyzed domestic and overseas academic journals to understand the research status and characteristics of radon concentration distribution in Korea in accordance with environmental conditions. Methods: As part of the meta-analysis, pooled average concentration was calculated using an inverse variance-weighted average of the arithmetic means and standard deviations among the investigated values. Using the obtained pooled average concentration, a Monte-Carlo simulation was performed to increase the reliability of the occurrence possibility of the calculated concentration distribution. A total of 38 research articles were selected, including 27 articles published in domestic academic journals and 11 articles published in foreign academic journals. Results: The comparison results showed differences in radon concentration distribution in accordance with regional and topographical characteristics. Conclusion: Currently, even though research into radon is steadily picking up the pace in Korea much remains to be done. Additional research is thus needed to establish a baseline for radon emissions in Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.1-10
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• 1990

The purpose of the study was to analyze air quality in underground shopping centers using pattern recognition methods. In order to perform this, the concentraion of air pollutants such as $CO, NO_2, NO_x, SO_2$, and particulate matters was measured at the 11 different shopping centers in Seoul metropolitan area and the total of 47 samples were obtained at random based on the size of shopping centers. To introduce a new concept of the "average concentration" for the indoor air quality analyses, the various multivariate statistical analyses have been studied. Thus, a cluster analysis was applied to separate the samples into pseudo-patterns and a disjoint principal component analysis was used to generate homogeneous patterns after removing outliers from the pseudo-patterns. The 6 homogeneous patterns were then obtained as follows:the first pattern was a group of clean sites;the second a group of sites having high dust concentration;the third a group of sites having high dust and $NO_x$ concentration;the fourth a group of sites having low dust and $SO_2$ concentraion and high CO concentration;the fifth a group of sites having high $NO_2 and SO_2$ concentration;and the final a group of miscellaneous sites. Thus, the average concentration could be estimated for each pattern.h pattern.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1955-1963
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• 2021

As the IAEA has applied integrated safeguards and a state level approach to member states, the importance of national inspection has increased. However, the requirements for national inspection for some member states are different from the IAEA safeguards. In particular, the national inspection for the ROK requires on-site U concentration analysis due to a domestic notification. This research proposes an on-site U concentration analysis (OUCA) method for UO₂ pellets using gamma spectroscopy to satisfy the domestic notification requirement. The OUCA method calculates the U concentration of UO₂ pellets using the measured net X-ray counts and declared ²³⁵U enrichment. This research demonstrates the feasibility of the OUCA method using both MCNP simulation and experiment. It simulated and measured the net X-ray counts of different UO₂ pellets with different U concentrations and ²³⁵U enrichments. The simulated and measured net X-ray counts were fitted to polynomials as a function of U concentration and ²³⁵U enrichment. The goodness-of-fit results of both simulation and experiment demonstrated the feasibility of the OUCA method.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.583-591
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• 2021

In this study, the applicability and reproducibility of LIBS in the analysis of chloride penetration in the mortar section were investigated. Standard analysis (IC, potentiometric titration) and LIBS analysis were simultaneously performed on the accelerated and immersed mortar by chloride concentration. Through LIBS analysis after making an eluate at the same depth for each concentration, the signal intensity of chloride ions was confirmed according to the depth and concentration at the wavelength of 837.59 nm, and a correlation between the LIBS signal intensity and the chloride concentration was confirmed. Although it is an aqueous solution-based LIBS analysis, the applicability and reproducibility of LIBS were confirmed not only for the incorporation of chloride but also for the amount of permeated chloride.

• Journal of Environmental Health Sciences
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• v.38 no.1
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• pp.31-41
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• 2012

Objectives: Biomonitoring is used to assess human environmental exposures. Urinary biomonitoring data are typically adjusted to a constant creatinine concentration to correct for variable dilutions among spot samples. Our objective was to investigate urinary creatinine concentrations by region, gender, age and lifestyle. Methods: We studied urinary creatinine concentrations in 6,286 Koreans aged 20 years old and older who participated the fourth Korea National Health and Nutrition Survey (KNHANES IV) in 2009. Urinary creatinine concentration analysis used the Jaffe method. Results: The average urinary creatinine concentration of 6,286 Koreans was 158.99 mg/dl. The urinary creatinine concentration was significantly higher among men (184.97 mg/dl) than women (130.02 mg/dl). In both men and women, urinary creatinine concentrations were significantly different according to age group (p < 0.01). Whereas the urinary creatinine concentration of men significantly differed with smoking in adjusted comparison analysis, that of women significantly differed by education level. Ninety-two percent of urinary creatinine concentration was included within WHO guidelines effective range(30 mg/dl ${\leq}$ urinary creatinine concentration ${\leq}$ 300 mg/dl). In multiple regression analysis, creatinine was influenced by gender, age and body mass index (BMI). Conclusions: The urinary creatinine value obtained from representative samples of adult Koreans aged 20 year and older in KNHANES IV 2009 could be used as a reference value for other nationally studied surveys, such as abandoned metal mine surveys and surveys for industrial complexes.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.815-824
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• 2012

The purpose of this study was to analyze the meteorological characteristics of wintertime high PM10 concentration episodes in Busan. $PM_{10}$ concentration has been reduced for the past four years and recorded near or exceeded 100 ${\mu}g/m^3$ (national standard of $PM_{10}$). High concentration episodes in Busan were 6 case, $PM_{2.5}/PM_{10}$ ratio was 0.36~0.39(mean 0.55). High $PM_{10}$ concentration occurred during higher air temperature, more solar radiation and sunshine, lower relative humidity, and smaller cloud amount. Synoptically, it also occurred when Busan was in the center or the edge of anticyclone and when sea breeze intruded. An analysis of upper air sounding showed that high $PM_{10}$ concentration occurred when surface inversion layer and upper subsidence inversion layer existed, and when boundary layer depth and vertical mixing coefficient were low. An analysis of backward trajectory of air mass showed that high $PM_{10}$ concentration was largely affected by long range transport considering that it occurs when air mass is intruded from China.