• Journal of the Korean earth science society
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• v.27 no.6
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• pp.643-652
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• 2006

Data of the carbon monoxide concentration observed in Mt. Waliguan in China (WLG), Ulaan Uul in Mongolia (UUM), Tae-ahn Peninsula in Korea (TAP), and Ryori in Japan (RYO) were analyzed for a long period between 1991 and 2004. The annual average concentration of carbon monoxide was the highest at TAP $(233{\pm}41ppb)$ followed by $RYO(171{\pm}36ppb),\;UUM(155{\pm}26ppb),\;and\;WLG(135{\pm}22ppb)$. The seasonal variations being high in spring and low in summer were observed in other areas of Eastern Asia except WLG. TAP was high in carbon monoxide concentration in all seasons compared to WLG, UUM and RYO and shows wide distribution of concentration in the histogram, which is caused by the influence of large-scale air pollution due to its downwind location close to the East Asian continent, China in particular. Also, our data was compared with data measured at Mauna Loa (MLO) in Hawaii. According to the origin of the isentropic backward trajectory and its transport passage, carbon monoxide concentration observed in TAP was analyzed as follows: continental background airflows (CBG) were $216{\pm}47ppb$; regionally polluted continental airflows (RPC) were $316{\pm}56ppb$; Oceanic background airflows (OBG) were $108{\pm}41ppb$; and Partly perturbed oceanic airflows (PPO) were $161{\pm}6ppb$. The high concentration of carbon monoxide in TAP is due to the airflow from East Asian continent origin rather than that from the North Pacific origin. Especially, RPC which passes through the eastern China appeared to be the highest in concentration in spring, fall, and winter. However, OBG was affected by the North Pacific air mass with a low carbon monoxide concentration in summer. The NOAA satellite images and GEOS-CHEM model simulation confirmed a large-scale air pollution event that was in the course of expansion from southeastern China bound to the Korean Peninsula and the Korea East Sea by way of the Yellow Sea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1460-1466
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• 2012

The purpose of this study was to evaluate plasticizer pollution levels in mudflat solar salt, salt water and sea water of the nationwide saltpan. Also, it was analyzed the relationship between DEHP in solar salt and PVC mat following private period. DEP (ranging from 0.00 to 1.55 ppb), DIBP (0.00~2.38), DBP (0.00~4.90), DEHA (0.00~2.32), and BBP (0.00~1.45) in solar salt were shown a extremely low concentrations, and DEHP was present a concentrations ranging from 0.00 to 268.5 ppb in solar salt. Further, DMP, DPrP, DNPP, DNHP, and DCHP were not detected in all solar salt. Phthalate in sea water and salt water was present a infinitesimal amount levels. DEHP levels in sea water and salt water were not shown a high risk levels ranging from 0.00 to 3.4 ppb, and from 0.00 to 21.4 ppb, respectively. As expected in PVC mat of nationwide saltpan, the correlation between DEHP in solar salt and PVC mat private period showed a low positive correlation coefficient ($r^2$=0.0362).

• Journal of Food Hygiene and Safety
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• v.16 no.3
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• pp.200-205
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• 2001

In this study, occurrence of aflatoxin M$_1$(AEM$_1$) in domestic milk and milk products was determined. The level of AFM$_1$ in market milk (0.047 ppb) was lower than that in raw milk (0.083 pub) but this looks like that is due to dilution in collecting process rather than the effect of sterilization. In the case of nonfat dry milk, level of AFM$_1$appeared high by 0.24 ppb but it is thought to be not different from market milk actually because nonfat dry milk is diluted at intake. In the case of ice cream, finished products were contaminated with AFM$_1$of 0.020 ppd and also have the possibility of the contamination of AFB$_1$due to secondary raw material such as nuts and almond. On the basis of the results of this study and previous studies, Monte-Carlo simulation is conducted to estimate the contamination level of AFM$_1$in domestic market milk. To consider uncertainty and variability fitting procedure was passed through. And we used beta distribution to estimate the prevalence and triangular distribution to estimate the concentration level of AFM$_1$in milk. As a result, the 5%, 50% and 95% points of the distribution of the probability of AFM$_1$contamination level in milk is 0.0214, 0.0946 and 0.1888 ppb, respectively. Also we estimate that AFM$_1$in almost milk was low more than 0.5 ppb that is American acceptable level but 80.4% exceeded far 0.05 ppb that is European standard.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.137-142
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• 2011

This study was conducted to establish the optimal electrolyte and bismuth concentrations using bismuth film electrode in laboratory and to confirm the possibilities of using this operational condition for heavy metals monitoring in field. In lab test, heavy metal measurement was not accurate more than 600 ppb when heavy metal (Pb, Cd, Zn) range 100~1,000 ppb was measured with bismuth 2,000 ppb. So, bismuth and heavy metal was reacted about 1:1 with ASV method. In electrolyte test, 0.1 M acetate buffer (pH 4.5), 0.1 M chloroacetate buffer (pH 2.0), 0.1 M HCl (pH 2.0), 0.1 M $HNO_3$ (pH 2.0) was tested. As a results, 0.1 M acetate buffer was most suitable in ASV measurement with bismuth film electrode. In field application, Pb, Cd and Zn was measured respectively 36~45 ppb, 84~91 ppb, 90~98 ppb when heavy metal (Pb, Cd, Zn) 100 ppb was spiked in field sample. These results were identified of matrix effect in field sample, So relationship between heavy metal measurement and matrix effects will be studied.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.11-20
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• 2009

This study was conducted in industrial area. The level of nitrogen dioxide was measured indoor, outdoor, work and personal in an study area within 5 km from source of pollution and control area 15 km farther from August, 2006 to September. The followings are the summary of this research. The concentration of the indoor and the outdoor $NO_2$ levels in the industrial area are 18.41$\pm$6.35 ppb, 18.51$\pm$3.26 ppb each, and the indoor/outdoor concentration rate is 0.99. The concentration of $NO_2$ in the workplace is 18.59$\pm$10.16 ppb, and the individual exposure rate is 18.80$\pm$5.71 ppb. The concentration of the indoor and the outdoor $NO_2$ levels control area are 12.57$\pm$3.82 ppb, 9.68$\pm$2.16 ppb each, and the indoor/outdoor concentration rate is 1.33. The personal exposure rate is 14.49$\pm$10.06 ppb. The residents of the each area and those of the comparative area spend 80.9% and 76.9% each their time in the indoor. It shows they spend most of their time in indoor. The predictions of the individual exposure rates in the industrial area and the comparative area are 15.10$\pm$6.14 ppb and 10.52$\pm$3.82 ppb each, The concentration levels measured by passive sampler are 18.80$\pm$5.71 ppb and 14.49$\pm$10.34 ppb each. The result of the research is the analysis of the personal exposure rate in indoor, outdoor and workplace of industrial area. This research may bo used as a basic data to manage and to establish the plan for $NO_2$ gas of the industrial area.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.20-26
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• 2001

personal nitrogen dioxide(NO$_2$) exposures for 31 professional drivers were measured using passive sampler and time activity diary in Asan and Chunan area, and were estimated using time-weighted average model. Mean concentrations of driver’s indoor and outdoor were 24.7$\pm$10.7 ppb and 23.3$\pm$8.3 ppb, respectively with indoor/outdoor of 1.1. Mean personal NO$_2$ exposure was 30.3$\pm$9.7 ppb. Personal NO$_2$ exposures were strongly correlated with indoor car NO$_2$ levels ($R^2$=0.80) rather than residential indoor NO$_2$ level ($R^2$=0.55). and outdoor NO$_2$ level ($R^2$=0.50). The driver’s NO$_2$ exposure using LP-gas with 24.4$\pm$8.0 ppb were statistically different from those using diesel with 36.3$\pm$14.1 ppb(p<0.01). The effect of driver’s smoking for personal NO$_2$ exposure was not found. It was considered that the main NO$_2$in driver is transportation. Since drivers mostly spent their times in indoor and inside car, time-weighted average model could be used to estimated personal NO$_2$ exposure using time activity diary, Though we did not measure all microenvironments, the estimated personal NO$_2$ exposures with 26.9$\pm$10.2 ppb were statistically correlated with measured personal NO $_2$ exposures30.3$\pm$9.7 ppb ($R^2$=0.89). The mean and standard deviation of personal NO$_2$ exposure using Mote-Carlo simulation were 26.6$\pm$7.2 ppb.

• Journal of environmental and Sanitary engineering
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• v.18 no.1
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• pp.58-67
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• 2003

The characteristics of the commercial garbage-decomposing accelerant, Raw Material of Pomia(RMP), Pomia and Vitabio. were analyzed. In HPLC pattern, Pomia and Vitabio showed main peak of about 30kDa in 280nm wave length. RMP, Pomia and Vitabio showed three, two and two peaks in 210nm. K and Na ion content of RMP were 2,620 and 1,590ppm, respectively, and their content were the largest one among others. Ca, Mg and Mn ion content of RMP were also the largest one, but Zn ion content was the least one. $Cl^{-}$, $F^{-}$ and $NO_3^{-}$ ion content of RMP were the largest one, especially $Cl^{-}$ content was 3,553ppm. pH values of RMP and Pomia were in neutral region, but Vitabio was 9.03. Dried residue content of RMP, Pomia and Vitabio were 1.4%, 0.55% and 0.4%, respectively. The number of general bacteria on PCA plate from RMP, Pomia and Vitabio were 2.2{\times}10^{6}cfu/ml,{\;}6.5{\times}10^{3}cfu/ml{\;}and{\;}1.1{\times}10^{3}cfu/ml$, respectively. The number of facultative anaerobes of RMP was $4.4{\;}{\times}{\;}10^{4}cfu/ml$, and it was biggest one. Lactobacilli and yeasts were found less than 10cfu/ml at best. The bacterium exists in RMP in high frequency was identified as Bacillus subtilis. Volatile sulfur compound amount of garbage samples treated with Pomia and Vitabio in concentration of 1/500 at $33^{\circ}C$ for 8 days were 1,273ppb and 1,902ppb, respectively, and control showed 3,015ppb. Volatile organic compound amount of the garbage samples treated were 68,312ppb, 124,317ppb and 263,954ppm, respectively. Diethylamine that known as malodor compound were 5,107ppb, 261ppb and 11,124ppb, respectively.

• Fire Science and Engineering
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• v.28 no.6
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• pp.108-113
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• 2014

The combined process of Sliding Arc Plasma and corona dielectric barrier discharge process (CDBD) was used to efficiently improve harmful substance, which convert into OH radicals which have strong oxidation potential, and so have deodorization and sterilizing effects, by generating specific radicals and anion and then reacting with the moisture contained in harmful substance. As a result of experiment, even if the size of SAP reactor is reduced from 80 A to 50 A, there is no much change and therefore it is judged the size of reactor may be minimized. And it was confirmed that after the anion and ozone generated from CDBD rector react with harmful substance, a anion was reduced from 510,000 ppb to 470 ppb and ozone from 98 ppb to 22 ppb. It was also judged the stability and durability of plasma producer are excellent. Accordingly, it is considered the harmful substances which exist in indoor air quality will be efficiently improved and removed by using further plasma combined process through this study.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.257-267
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• 1996

One hundred of thirty volcanic rocks col1ected from the Jeju island， Jeongog， Guryongpo and other areas were analyzed for major elements and trace elements with Au by inductively coupled argon plasma and graphite furnace atomic absorptiom spectrometry. The Au content is the highest values (0.2~43.4 ppb, average; 10.34 ppb) from the Jeju island volcanic rocks and the lowest (0.5~11.0 ppb, average; 1.23 ppb) from the Guryongpo volcanic area. The content of Au tends to be higher in the Quarternary volcanic rocks than Tertiary or Cretaceous volcanic rocks. The Au content of the calc alkali volcanic rocks tends to increase from mafic to felsic volcanic rocks, but that of the alkalic volcanic rocks tends to increase from felsic to mafic volcanic rocks. The Au content of the volcanic rocks collected from the Jeju island shows the highest values in the feldspar olivine basalts. Elements or oxides which have positive or negative correlations with Au are Ag, Mo, Rb, V, Y, $K_2O$, MgO and $SiO_2$, but other elements analyzed are not shown correlations with Au. It has a tendency to show that samples from the Jeju with 5 ppb gold and more are plotted in the non-Dupal area and those with less than 5 ppb gold in the Dupal area, while those from the Jeongog with 5 ppb gold and more are plotted in the Dupal area and those with less than 5 ppb gold in the non-Dupal area, in the Ba/Nb-La/Nb, Zr/Nb-Ba/Nb diagrams. It shows that samples from the Jeju and Guryongpo with high gold content are plotted in the within-plate, while those with low gold content are plotted in the arc-related area, and those from the Jeongog are scattered in the $TiO_2-Al_2O_3$, $Zr/A1_2O_3-TiO_2/Al_2O_3$ diagrams.

• Plant Journal
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• v.9 no.4
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• pp.26-30
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• 2013

Based on case that HRSG low pressure steam generator tube was damaged by FAC in 500 MW A CCPP. This case analyzed the effect of application about the block of hydrazine water treatment which is applied for increasing dissolved oxygen. And also try to deduce the major factor of FAC Which is caused by lacking of dissolved oxygen of boiler feed system. After 1 year of water treatment, the figure of dissolved oxygen in the boiler feed water has increased from 0.15 ppb to 3~5 ppb and the figure of oxidation reduction potential has increased from -245 mV to 170 mV. And Iron content, the corrosion products by FAC has decreased from 18.5 ppb to 5~7 ppb. According to the result of experiment, we could able to confirm that the interception of hydrazine of water treatment is effective to reduce FAC.