• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.343-350
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• 2007

Three different experiments were carried out to investigate the runoff and erosion losses of endosulfan from sloped-field by rainfall. The mobility of endosulfan and which phase it was transported by were examined in adsorption study, the influence of rainfall pattern and slope degree on the pesticide loss were evaluated in simulated rainfall study, and the pesticide losses from soybean-grown field comparing with bare soil were measured in field lysimeter study. Adsorption parameter (K) of endosulfan ranged from 77 to 131 by adsorption method and K values by the desorption method were higher than those by the adsorption method. By the SSLRC's classification for pesticide mobility endosulfan was classified as non-mobile class ($K_{oc}>4,000$). Runoff and erosion loss of endosulfan by three rainfall scenarios ranged from 3.4 to 5.6%and from 4.4 to 15.6%of the amount treated. Endosulfan residues were mainly remained at the top 5 cm of soil depth after the simulated rainfall study. Pesticide loss in case of 30%-slope degree ranged from 0.6 to 0.9 times higher than those in case of 10%-slope degree. The difference of pesticide runoff loss was related with its concentration in runoff water and the difference of pesticide erosion loss would related closely with the quantity of soil eroded. Endosulfan losses from a series of lysimeter plots in sloped land by rainfall ranged from 5 to 35% of the amount treated. The erosion rate of endosulfan from soybean-plots was 66% of that from bare soil plots. The effect of slope conditions was not great for runoff loss, but was great for erosion loss as increasing to maximum $4{\sim}12$ times with slope degree and slope length. The peak runoff concentration of endosulfan in soybean-plots and bare soil plots ranged from 8 to 10 and from 7 to $9{\mu}gL^{-1}$ on nine plots with different slope degree and slope length. Therefore the difference of the peak runoff concentrations between bare soil plots and soybean-plots were not great.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.35-44
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• 2015

Forests contain a huge amount of carbon (C) and climate change could affect forest C dynamics. This study was conducted to predict the C dynamics of Pinus densiflora and Quercus variabilis forests, which are the most dominant needleleaf and broadleaf forests in Korea, using the Korean Forest Soil Carbon (KFSC) model under the two climate change scenarios (2012-2100; Constant Temperature (CT) scenario and Representative Concentration Pathway (RCP) 8.5 scenario). To construct simulation unit, the forest land areas for those two species in the 5th National Forest Inventory (NFI) data were sorted by administrative district and stand age class. The C pools were initialized at 2012, and any disturbance was not considered during the simulation period. Although the forest C stocks of two species generally increased over time, the forest C stocks under the RCP 8.5 scenario were less than those stocks under the CT scenario. The C stocks of P. densiflora forests increased from 260.4 Tg C in 2012 to 395.3 (CT scenario) or 384.1 Tg C (RCP 8.5 scenario) in 2100. For Q. variabilis forests, the C stocks increased from 124.4 Tg C in 2012 to 219.5 (CT scenario) or 204.7 (RCP 8.5 scenario) Tg C in 2100. Compared to 5th NFI data, the initial value of C stocks in dead organic matter C pools seemed valid. Accordingly, the annual C sequestration rates of the two species over the simulation period under the RCP 8.5 scenario (65.8 and $164.2g\;C\;m^{-2}\;yr^{-1}$ for P. densiflora and Q. variabilis) were lower than those values under the CT scenario (71.1 and $193.5g\;C\;m^{-2}\;yr^{-1}$ for P. densiflora and Q. variabilis). We concluded that the C sequestration potential of P. densiflora and Q. variabilis forests could be decreased by climate change. Although there were uncertainties from parameters and model structure, this study could contribute to elucidating the C dynamics of South Korean forests in future.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.279-288
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• 2006

Three different experiments were undertaken to investigate the runoff and erosion loss of diazinon and metolachlor from sloped-field by rainfall. The mobility of two pesticides and which phase they were transported by were examined in adsorption study, the influence of rainfall pattern and slope degree on the pesticide losses were evaluated in simulated rainfall study, and the pesticide losses from soybean field comparing with bare soil were measured in field lysimeter study. Freundlich adsorption parameter (K) ranged $1.6{\sim}2.0$ for metolachlor and $4.0{\sim}5.5$ for diazinon. The K values of pesticides by the desorption method were higher than those ones by the adsorption method. Another parameter (1/n) in Freundlich equation for the pesticides tested ranged $0.96{\sim}1.02$ by desorption method and $0.87{\sim}1.02$ by adsorption method. By the SSLRC's classification for pesticide mobility of diazinon and metolachlor were classified as moderately mobile ($75{\leq}Koc$ <500). Runoff and erosion losses of pesticides by three rainfall scenarios were $0.5{\sim}1.0%$ and $0.1{\sim}0.7%$ for metolachlor and $0.1{\sim}0.6%$ and $0.1{\sim}0.2%$ for diazinon. Distribution of pesticides in soil polite were investigated after the simulated rainfall events. Metolachlor was leached to $10{\sim}15$ cm soil layer and diazinon was leached to $5{\sim}10$ cm soil layer. Losses of each pesticide in the 30% of sloping degree treatment were $0.2{\sim}1.9$ times higher than those ones in the 10% of sloping degree treatment. Pesticide losses from a series of lysimeter plots in sloped land by rainfall ranged $1.0{\sim}3.1%$ for metolachlor and $0.23{\sim}0.50%$ for diazinon, and were $1/3{\sim}2.5$ times to the ones in the simulated rainfall study. The erosion rates of pesticides from soybean-plots were $21{\sim}75%$ lower than the ones from bare soil plots. The peak runoff concentration in soybean-plots and bare soil plots were $1{\sim}9{\mu}gL^{-1}$ and $3{\sim}16{\mu}gL^{-1}$ for diazinon, $7{\sim}31{\mu}gL^{-1}$ and $5{\sim}40{\mu}gL^{-1}$ for metolachlor, respectively.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1475-1490
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• 2021

Detecting oil spill area using statistical characteristics of SAR images has limitations in that classification algorithm is complicated and is greatly affected by outliers. To overcome these limitations, studies using neural networks to classify oil spills are recently investigated. However, the studies to evaluate whether the performance of model shows a consistent detection performance for various oil spill cases were insufficient. Therefore, in this study, two CNNs (Convolutional Neural Networks) with basic structures(Simple CNN and U-net) were used to discover whether there is a difference in detection performance according to the structure of CNN and distribution characteristics of oil spill. As a result, through the method proposed in this study, the Simple CNN with contracting path only detected oil spill with an F1 score of 86.24% and U-net, which has both contracting and expansive path showed an F1 score of 91.44%. Both models successfully detected oil spills, but detection performance of the U-net was higher than Simple CNN. Additionally, in order to compare the accuracy of models according to various oil spill cases, the cases were classified into four different categories according to the spatial distribution characteristics of the oil spill (presence of land near the oil spill area) and the clarity of border between oil and seawater. The Simple CNN had F1 score values of 85.71%, 87.43%, 86.50%, and 85.86% for each category, showing the maximum difference of 1.71%. In the case of U-net, the values for each category were 89.77%, 92.27%, 92.59%, and 92.66%, with the maximum difference of 2.90%. Such results indicate that neither model showed significant differences in detection performance by the characteristics of oil spill distribution. However, the difference in detection tendency was caused by the difference in the model structure and the oil spill distribution characteristics. In all four oil spill categories, the Simple CNN showed a tendency to overestimate the oil spill area and the U-net showed a tendency to underestimate it. These tendencies were emphasized when the border between oil and seawater was unclear.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.2
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• pp.205-216
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• 2023

This study aimed to compare the color stability and surface roughness of three-dimensional (3D) printing resin according to polishing methods. 3D-printed resin specimens were fabricated at TC-80DP (Graphy, Seoul, Korea) with a stereolithography 3D printer, and the specimens were divided into three groups, each of which was not polished, was polished using Enhance^®, and was polished using a Sof-Lex^TM disc. The CIE L^*a^*b^* value and the surface roughness of each group were measured and immersed in artificial saliva and orange juice after 0, 1, 7, 30, and 60 days, and the color difference (ΔE^*) was calculated. As a result of the study, no noticeable color change was observed in artificial saliva, but a noticeable color change was demonstrated in orange juice after 60 days of immersion, and the difference was significant. In the Sof-Lex^TM group, surface roughness according to the solution was found to be significantly higher in the orange juice than that in artificial saliva. No significant difference in color change was found according to the polishing method, but surface roughness was significantly lower in the Sof-Lex^TM group than both that of the unpolished group and that of the Enhance^® group. Nevertheless, all groups exhibited clinically acceptable properties regardless of their higher surface roughness than the threshold for plaque accumulation. Overall, this study recommends utilizing Sof-Lex^TM for polishing 3D printing resin when used in primary anterior tooth coverage.

• Korean Journal of Culture and Social Issue
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• v.29 no.2
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• pp.171-197
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• 2023

The traditional Korean society has been classified as an Eastern collectivist culture, but in the flow of globalization and digitalization along with the post-Cold War era of the 1970s, Western individualistic culture and values quickly permeated the Korean younger generation. Since rapid changes occurred within a short period of time, there may be differences in cultural self-construal between generations living in the same era. Due to this, psychological problems related to emotional expression and suppression may appear differently depending on generations. Therefore, in the current study, 1,000 Korean adult men and women from their 20s to 60s were investigated for their level of independent and interdependent self-construal, alexithymia, ambivalence over emotional expression(AEE) and emotional suppression(ES). Then the relationship between the variables(self-construal and alexithymia,) and the mediating process of AEE and ES were examined. The generation of participants were divided into the industrialization cohort (birth year < 1970) and the digitalization cohort (birth year starting from 1970). Using the PROCESS macro(Hayes, 2022), we tested a serial mediation model of AEE and ES between the relative independent self-construal(RIS) and alexithymia. The results indicate that the level of alexithymia increases by the serial increase of AEE and ES when RIS decreases. Next, we examined a moderation effect of generatione on the mediation process of AEE and ES, and found that generation moderates the relationship between ES and alexithymia. That is, the effect of ES on alexithymia is significant for the digitalization cohort, while it is not significant for the industrialization cohort. The current results imply that emotion regulation strategies of Koreans have been differently developed according to prevailing cultural values in each generation, and that the negative influence of emotion suppression could be different according to the cultural background of each generation.

• Analytical Science and Technology
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• v.21 no.5
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• pp.383-391
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• 2008

International Agency for Research on Cancer (IARC) has classified it as a possible carcinogen and World Health Organization (WHO) has suggested 50 ng/mL as a guideline value for 1,4-dioxane. Considering the toxicity of 1,4-dioxane and ingestion rate of drinking water, the monitoring of 1,4-dioxane in drinking water in Nakdong river is very important. We analyzed 1,4-dioxane four times per year for the 12 samples of treated water and 4 samples of raw water in Nakdong river in Korea from 2000 to 2007 and surveyed the trend of concentrations of 1,4-dioxane. As a results of analysis, 1,4-dioxane was detected from 0.24 to 240.2 ng/mL in treated water and from 0.39 to 81.9 ng/mL in raw water from 2000 to 2007. The average concentrations are 22.68 ng/mL and 19.15 ng/mL in treated water and raw water, respectively. The detected concentrations was decreased but frequency of detection was not changed since establishment of regulation in 2004. Results of comparison of 95 percentile excessive cancer risk of 1,4-dioxane in treated and raw water were each $6.63{\times}10^{-6}$, $3.17{\times}10^{-6}$ before 2004 and $2.10{\times}10^{-6}$, $1.22{\times}10^{-6}$ after 2004. Also, comparing the detected concentration and frequency for each season, these were more detected the concentration and frequency for 1,4-dioxane in treated and raw water from winter to spring.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4B
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• pp.385-396
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• 2009

Non-household unit water use for each type of business are estimated in this study. The business types are subdivided into forty based on nine categories by the national industrial standard classification, such as office, commerce, public bathing, public water use etc. Correlation analysis and analysis of variance (ANOVA) are applied to obtain statistical characteristics between industrial water use data, surveyed in six cities including Nonsan, Seosan and the National Statistical Bureau and site area, employees number etc. for each detailed business area. As the proposed non-household unit water uses are compared with five surveyed data in USA, it is shown that almost of water uses per unit area are less than those in USA. Non-household unit water uses of 25% cumulative probability water use recommended as efficiency benchmarks among surveyed data in Korea are also less than those in USA. Especially, in the case of water use in school, the average and the range are similar results showing water use range between 0.4 and 6.2 ($l/m^2/day$) as liter per capita day per an unit area, also water use range between 11.9 to 64.0 (l/student/day) as liter per capita day per a person. From the result of correlation analysis with internal and exogenous affecting factors on non-household water use, it can be concluded that a unit area is most appropriate factor as a standard of non-household unit water use. In case of water use in educational business, the number of students including staffs is more correlated than site ares with water use for the settled water consumption tendency. Although the increase and decrease of educational institutes, retail/wholesale store and restaurants are shown remarkable by the temperature as a representative factor, low correlations are shown in water use fluctuation in lodging house and hospital.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.390-401
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• 2023

Major components of lac coloring include laccaic acids A, B, C, and E. The Korean Food Additive Code regulates the use of lac coloring and prohibits its use in ten types of food products including natural food products. Since no commercial standards are available for laccaic acids A, B, C, and E, a standard for lac pigment itself was used to separate laccaic acids from the lac pigment molecule. A standard for each laccaic acid was then obtained by fractionation. To obtain pure lac pigment for use in food by High performance Liquid Chromatography Photo Diode Array (PDA), a C8 column yielded the best resolution among various tested columns and mobile phases. A qualitative analytical method using High Performance Liquid Chromatography (HPLC) Tandem Mass(LC-MS/MS) was developed. The conditions for fast and precise sample preparation begin with extraction using methanol and 0.3% ammonium phosphate, followed by concentration. The degree of precision observed for the analyses of ham, tomato juice and Red pepper paste was 0.3-13.1% (Relative Standard Deviation (RSD%)), degree of accuracy was 90.3-122.2% with r²=0.999 or above, and recovery rate was 91.6-114.9%. The limit of detection was 0.01-0.15 ㎍/mL, and the limits of quantitation ranged from 0.02 to 0.47 ㎍/mL. Lac pigment was not detected in 117 food products in the 10 food categories for which the use of lac pigment is banned. Multiple laccaic acids were detected in 105 food products in 6 food categories that are allowed to use lac color. Lac pigment concentrations range from 0.08 to 16.67 ㎍/mL.

• The Korean Journal of Nuclear Medicine Technology
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• v.26 no.2
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• pp.43-47
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• 2022

Purpose Radioimmunoassay implement quality control by systematizing the internal quality control system for quality assurance of test results. This study aims to contribute to the quality assurance of radioimmunoassay results and to implement systematic quality control by measuring the average CV of internal quality control and external quality control by plenty of institutions for reference when setting the laboratory's own acceptable range. Materials and Methods We measured the average CV of internal quality control and the bounce rate of more than 10.0% for a total of 42 items from October 2020 to December 2021. According to the CV result, we classified and compared the upper group (5.0% or less), the middle group (5.0~10.0%) and the lower group (10.0% or more). The bounce rate of 10.0% or more was compared by classifying the item of five or more institutions into tumor markers, thyroid hormones and other hormones. The average CV was measured by the overall average and standard deviation of the external quality control results for 28 items from the first quarter to the fourth quarter of 2021. In addition, the average CV was measured by the overall average and standard deviation of the proficiency results between institutions for 13 items in the first half and the second half of 2021. The average CV of internal quality control and external quality control was compared by item so we compared and analyzed the items that implement well to quality control and the items that require attention to quality control. Results As a result of measuring the precision average of internal quality control for 42 items of six institutions, the top group (5.0% or less) are Ferritin, HGH, SHBG, and 25-OH-VitD, while the bottom group (≤10.0%) are cortisol, ATA, AMA, renin, and estradiol. When comparing more than 10.0% bounce rate of CV for tumor markers, CA-125 (6.7%), CA-19-9 (9.8%) implemented well, while SCC-Ag (24.3%), CA-15-3 (26.7%) were among the items that require attention to control. As a result of comparing the bounce rate of more than 10.0% of CV for thyroid hormones examination, free T4 (2.1%), T3 (9.3%) showed excellent performance and AMA (39.6%), ATA (51.6%) required attention to control. When comparing the bounce rate of 10.0% or more of CV for other hormones, IGF-1 (8.8%), FSH (9.1%), prolactin (9.2%) showed excellent performance, however estradiol (37.3%), testosterone (37.7%), cortisol (44.4%) required attention to control. As a result of measuring the average CV of the whole institutions participating at external quality control for 28 items, HGH and SCC-Ag were included in the top group (≤10.0%), however ATA, estradiol, TSI, and thyroglobulin included in bottom group (≥30.0%). Conclusion As a result of evaluating 42 items of six institutions, the average CV was 3.7~12.2% showing a 3.3 times difference between the upper group and the lower group. Cortisol, ATA, AMA, Renin and estradiol tests with high CV will require continuous improvement activities to improve precision. In addition, we measured and compared the overall average CV of the internal quality control, the external quality control and the proficiency between institutions participating of six institutions for 41 items excluding HBs-Ab. As a result, ATA, AMA, Renin and estradiol belong to the same subgroup so we require attention to control and consider setting a higher acceptable range. It is recommended to set and control the acceptable range standard of internal quality control CV in consideration of many things in the laboratory due to the different reagents and instruments, and the results vary depending on the test's proficiency and quality control materials. It is thought that the accuracy and reliability of radioimmunoassay results can be improved if systematic quality control is implemented based on the set acceptable range.