• Analytical Science and Technology
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• v.23 no.3
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• pp.312-321
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• 2010

Seven indicator PCBs (IUPAC nos 28, 52, 101, 118, 138, 153, 180 congeners) concentrations were measured in food samples including cereal (polished rice), meats, eggs, milk and dairy products, and fisheries and products as representation for the general Korean populations during 2006-2007, and was analyzed using isotopic dilution method. Fishes had the highest average level as 39.8 ng/g, 1.4 ng/g for milk and dairy products, and 0.9 ng/g for meats. The hairtail out of fishes was contaminated at the level of 15.4 ng/g, 5.4 ng/g for pacific mackerel and spanish mackerel, and 4.5 ng/g for yellow croaker. The ratio for indicator PCBs in overall food was contributed as follows; 35.8% for PCB-153, 16.2% for PCB-138, 16.1% for PCB-101, 13.4% for PCB-118, 8.8% for PCB-180, 6.9% for PCB-52, and 2.9% for PCB-28. The hexa-CBs including PCB-153 and 138 were more predominated, and the next was penta-CBs including PCB-101 and 118 in food. For estimated daily intake (EDI) in average and $95^{th}$ percentile, fishes and products out of overall food were taken to represent over 50%. However, it was estimated that there was no adverse health effect for Korean.

• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.88-92
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• 2009

The effect of Chlorella vulgaris (CV) on the urinary excretion of di-ortho PCB congeners (PCB-138, -153) was investigated. Sprague-Dawley rats (6-weeks-old, n=10 rats/group) were randomly divided into one control (0CV) or 2% CV (2CV) or 5% CV (5CV) or 10% CV (10CV) groups, respectively. Composition of normal and chlorella meal-based diet were made up of 30% casein, 15% cornstarch, 50% sucrose, 5% cellulose, 5% coconut oil, 3.5% mineral mixture, 1 % vitamin mixture. All rats had free access to water and diet for 4 weeks. A significant increase in both PCB 138 and 153 in urinary level was detected in CV fed groups, 540% and 167% for 2CV, 155% and 89% for 5CV, 114% and 144% for 10CV group, respectively, when compared with their controls. These findings suggest that CV may have potential to eliminate body burden levels of dioxin-like PCB compounds.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.829-838
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• 2005

In order to investigate the residual amounts of organochlorines and polychlorinated biphenyls (PCBs) in Korean human tissues (blood, adipose tissue, liver, kidney cortex, and lung), the samples were collected from the autopsied cadavers of 40 men and 40 women (from teens to seventies of age). ${\alpha}-BHC,\;{\beta}-BHC,\;{\gamma}-BHC,\;{\delta}-BHC$, p,p'-DDT, p,p'-DDD, p,p'-DDE, endrin, dieldein, aldrin, and 7 marker PCBs (28, 52, 101, 118, 138, 153, and 180) were determined in human tissues. The levels of organochlorines and PCB congeners indicated that they have been widely distributed in Korean human body. Positive correlations in terms of age were observed for the following cases: p,p'-DDE, p,p'-DDT, ${\Sigma}-DDT$, PCB 118, PCB 138, PCB 153, and ${\Sigma}-PCB$ in the adipose tissue, and p,p'-DDE in the lung. Concentration of these compounds showed a significant age-related increase. Accumulation of these compounds in aged people revealed that these compounds were more slowly eliminated in our environment and risk assessment was necessary for further proper action. Significant differences in the levels of PCBs between genders were found for PCB 118 in the adipose tissue and PCB 138 in the liver. Positive correlation coefficients between tissues were detected with p,p'-DDE and ${\beta}-BHC$.

• Analytical Science and Technology
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• v.19 no.1
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• pp.73-85
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• 2006

Blood serum concentrations of polychlorinated biphenyls (PCBs) were measured in employees who worked at a municipal solid waste incinerator (MSWI), members of residential community who lived near the MSWI (<0.3km) and members of residential community lived far from the MSWI (>10 km). Human blood serum samples were analyzed for all PCB congeners using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The mean levels of total PCBs and dioxin-like PCBs in 87 serum samples were 242.77 ng/g lipid and 8.83 TEQ pg/g lipid, respectively. The PCB homologue profiles showed that penta-, hexa-, hepta-chlorinated biphenyls contributed more than 80% of the total PCBs concentration. The most abundant congeners were PCB153, PCB138, PCB180, PCB187, PCB118. A statistical analysis was performed to determine whether there were significant correlations between PCB concentrations and specific variables such as age, gender, smoking habits, occupation, BMI (Body Mass Index) and time of residence. As a result, the age was found to be strongly correlated with serum PCB concentrations. In addition, there were strong correlations between total PCBs and PCB153 (r=0.93, p<.0001), dioxin-like PCBs and PCB118 (r=0.98, p<.0001). So these two congeners are satisfactory indicators for total PCB concentrations and dioxin-like PCBs in human blood respectively.

• Analytical Science and Technology
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• v.16 no.2
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• pp.166-173
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• 2003

To determine levels of PCBs in food, beef, pork, chicken, egg, mackerel, yellow croaker, anchovy, common squid and little neck clam were chosen and collected at markets in Seoul, Busan and Kwangju. Among 209 PCB congeners, 7 congeners (#28, #52, #101, #118, #138, #153 and #180) were selected as target compounds that were known as indicator congeners. Samples were homogenized, treated in alkali solution for 1 hour, and extracted with organic solvents. After extraction, extracts were cleaned up by sulfuric acid, purified on silica gel column chromatography, analyzed by dual column-HRGC/ECD and then confirmed by HRGC/MSD. As results, PCBs were detected in fish samples ranged from 0.0002 to 0.001 mg/kg. Both PCB #101 and PCB #118 were the major contributors among 7 congeners.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3888-3893
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• 2014

The number of waste tires is increasing. One effective recycling method is the pyrolysis of waste tires. Using the pyrolyzed carbon black from waste tires, the characteristics of permanent deformation for PA-13mm porous mixture were evaluated. The confining pressure of 138 kPa and deviatoric stress of 551 kPa were adopted. The testing temperature was $45^{\circ}$ and 50 gyrations of the gyratory compactor was used to simulate the medium traffic level. The mixture modified by 10% PCB showed the largest Marshall Stability of 3.41 kN. The stability of the mixtures with PCB was 50% higher than that of mixture without PCB. The limited laboratory test showed that the use of PCB in a porous pavement decreases the permanent deformation and will be an effective alternative method to reducing the permanent deformation of a porous pavement.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.137-138
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• 2015

본 논문은 알루미늄 재질로 된 방열판을 LED조명기구에 적용해서 열 해석을 한 것으로서, PCB에 25[W]급 LED를 배치하여 COMSOL Multi-physics로 시뮬레이션 하였다. 그 결과 LED와 PCB 경계면의 온도는 $69^{\circ}C$이고, PCB바닥면의 온도는 $28^{\circ}C$로 실제작한 FR-4 재질의 LED Module과 근접한 온도임을 확인 할 수 있었다.

• Analytical Science and Technology
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• v.25 no.6
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• pp.421-428
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• 2012

In this study, PCDD/PCDFs, PAHs and PCBs in wastes from metal, plastic and wastewater treatment facilities were analyzed. The concentrations of PCDD/PCDFs ranged from 7.37~432.20 ng-TEQ/kg in fly ash, 0.51~855.01 ng-TEQ/kg in incinerated ash and 0.37~385.81 ng-TEQ/kg in dust. Dioxin content was lower, compared to data in foreign countries. PAHs concentration was in the range of 0.0075~2.9225 mg/kg for process sludge and 0.0035~1.6716 mg/kg for wastewater sludge, which satisfied all of the two standards (Nap, Ant, B(a)F:4/0.8, Phen, B(a)A:5/1, Flt:10/2.5, B(a)P:4.5/0.9) of the Marine Environment Management Act. PAHs concentration in process sludge and wastewater sludge were slightly lower than those abroad. According to the analysis of seven types of PCBs (in comparison with the first standard, 0.15 mg/kg), concentration was found in the range of 0.0~0.65 mg/kg, while PCB-52, PCB-101, PCB-138, PCB-153 and PCB-180 isomers were detected in excessive value in some machine oil and hydraulic fluid.

• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.138-143
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• 1999

Recently, miniaturization of large scale integrated circuits (LSI) and printed circuit board (PCB) have become essential with the downsizing of electronic devices. Gold electroplating is applied of conductivity wiring or terminals for improvement of conductivity and corrosion resistance. However, electroplating is not applicable since the circuits are becoming finer and denser. Accordingly, electroless plating is recently highly attractive method because of the simplicity of the operation requiring no external source of current and no elaborate equipment. In this work, we tried to develop a plating technique on electroless Ni/Au plating. First, the electroless Ni plating was deposited on the PCB with agitation in the bath at $85^{\circ}C$. Then the Au layer was deposited on the Ni layer surface by same method at $90^{\circ}C$. The bonderability were tested in order to evaluate the stability of the electroless Ni/Au by gold wire or solder ball test.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.138-144
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• 2010

This research deals with multiple Gantry-type assembly machines for the optimization of PCB assembly line. The automated assembly machine has 6 nozzles which can linearly move the X axis and the Y axis different from the turret type assembly machine. Each machine is optimized while considering the whole line balancing of three machines in assembly process simultaneously. Simulation models are developed using AutoMod for comparison study with single machine operation cases under various conditions such as types and total number of components to evaluate the proposed method.