• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.717-722
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• 2011

Currently, melamine is being used variously in our lives such as resins, flame retardants, adhesive, laminate etc. And understandably sewer of stream of wastewater containing Melamine has also increased. GHS (Globally Harmonized System of Classification and Labelling of Chemicals) of EU safety guidelines says that it can cause cancer. Still, study on toxicity of Melamine is going on. In this research, melamine contamination level of the Han River and River Basin was analyzed by HPLC/UV. And the experiments of GAC adsorption were conducted and the model was studied. We collected the 3 same samples at the suburbs of Paldang Dam located in the relative upstream in Han River and Ttukseom amusement park, the downstream region and collected samples equally at the Hongreung stream, Wangsuk stream, Cheonggye stream among streams flowing into Han River and then measured Melamine concentration after purification. As a result, melamine was not detected at the suburbs of Paldang Dam and it was detected at Ttukseom amusement park, the downstream of it, in the concentration of $0.312{\mu}g/L$. The Wangsuk stream with $0.578{\mu}g/L$ highest Cheonggye stream and Hongreung stream was detected with each $0.197{\mu}g/L$ and $0.325{\mu}g/L$. Although the concentration was low in general, melamine detection could be checked at most point. In 1970, the world capacity of Melamine was estimated at 200,000 ton, with current production estimated to be 1,400,000 ton. Melamine of Han River and rivers flowing into Han River is present at low concentration but pollution will increase in the future due to increase of use. Depending on the size of activated carbon in the experiment were slightly different. But the breakthrough model is almost identical.

• Journal of Nutrition and Health
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• v.24 no.4
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• pp.299-307
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• 1991

The present study was designed to evaluate the effects of dietary coenzyme $Q_{10}$ on mitochondrial coenzyme $Q_{10}$ and fatty acid composition in adriamycin (ADR)-treated rats. Two experiments were conducted in rats. Experiment 1 was undertaken under the condition of simultaneous administration of ADR and coenzyme $Q_{10}$ for 4 weeks. Experiment 2 was undertaken under the same condition as experiment 1 after feeding the experimental diets alone without administration of ADR for 4 weeks. Heart mitochondrial coenzyme $Q_{10}$ level of rats was greatly decreased by ADR treatment. but higher level of dietary coenzyme $Q_{10}$ elevated this decrease to control ranges. Pretreatment with dietary supplementation of coenzyme $Q_{10}$ showed a significant increase in myocardial coenzyme $Q_{10}$ level. With ADR treatment. polyunsaturated fatty acids such as arachidonic acid (20 : 4) and docosahexaenoic acid (22 : 6) were decreased. However, dietary supplementation of coenzyme $Q_{10}$ modified this decrement to some extent. In both experiment 1 and 2. the polyunsaturated fatty acids/saturated and polyunsaturated fatty acids (P/S+ M) ratio of ADR-treated rats tended to be lower than that of control rats.

• Resources Recycling
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• v.19 no.5
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• pp.31-43
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• 2010

To fabricate porous SiC candle filter for filtration facility of the IGCC system, the candle type filter preforms were fabricated by ramming and vacuum extrusion process. A commercially available ${\alpha}$-SiC powders with various particle size were used as starting raw materials, and $44\;{\mu}m$ mullite, $CaCO_3$ powder were used as non-clay based inorganic sintering additive. The candle typed preforms by ramming process and vacuum extrusion were sintered at $1400^{\circ}C$ for 2h in air atmosphere. The effect of forming method and particle size of filter matrix on porosity, density, strength (flexural and compressive strength) and microstructure of the sintered porous SiC candle tilters were investigated. The sintered porous SiC filters which were fabricated by ramming process have more higher density and strength than extruded filter in same particle size of the matrix, and its maximum density and 3-point bending strength were $2.00\;g/cm^3$ and 45 MPa, respectively. Also, corrosion test of the sintered candle filter specimens by different forming method was performed at $600^{\circ}C$ for 2400h using IGCC syngas atmosphere for estimation of long-term reliability of the candle filter matrix.

• Journal of Trauma and Injury
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• v.28 no.1
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• pp.9-14
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• 2015

Purpose: The aim of this study was to estimate the seropositive prevalence of blood-borne infection in neurotrauma patients who underwent emergent surgical intervention, especially patients with hepatitis B virus (HBV), hepatitis C virus (HCV), syphilis and human immunodefIciency virus (HIV). Methods: A retrospective review identified 559 patients with traumatic brain injury and spinal trauma who underwent emergent surgery between 2007 and 2014. We reviewed the medical records and extracted data, including age, sex, location of lesion, result of serologic tests, time interval of admission and surgery after presenting to emergency room. Serologic tests for HBV, HCV, syphilis and HIV were performed and analyzed to determine whether the seropositive results were confirmed by the surgeon before surgery. Results: The majority of the patients were male (74.6%), and the mean age was $55.4{\pm}20.2years$. Most patients underwent surgery due to traumatic brain injury (90.0%). Fifty-three patients (10.0%) showed a positive result on at least one serologic test. Seropositive rates according to pathogens were 0.5% for syphilis, 5.2% for HBV and 3.9% for HCV. No positive results were noted on the serologic tests for HIV. HBV in patients with spinal cord injury and age from 40 to 49 years were associated with high serologic positive rate, and that result was statistically significant. However, no statistically significant differences were found in the other variables. Serologic results could not confirmed before surgery in the majority of the cases (62.1%), and 10.4% of these patients showed seropositive results. Conclusion: The results of this study emphasize the importance of taking precautions and conducting rapid serologic testing in preventing the occupational transmission of blood-borne viruses to health-care workers.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.53-59
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• 1988

Recently, the formation of the complexes between macrocyclic polyethers and alkali metal salts have been determined by several methods. It has been suggested that the specificity of the complexation be due to the nature of the surrounding solvent molecules. The formation constant values ($K_f$) of $K^+$ are shown to be the largest among the other alkali metal cations because the ionic diameter of $K^+$ is approximately the same with the hole size of 18-crown-6. In this study the formation constants of the 1 : 1 complexes of 18-crown-6 with potassium p-substituted phenoxide are calculated by the conductance measurement in organic solvents. As a result, the $K_f$ value series among organic solvents are given in the order of $CH_3$OH > DMF > DMSO. It seems that the donor number of the solvent is a main factor in the formation of the complex between $K^+$ metal ion and 18-crown-6 molecules. At the same time, the formation constants increase with increasing the electron-withdrawing power of substituents because the phenoxide ion is stabilized by the charge dispersion.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.3 s.345
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• pp.1-8
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• 2006

In this paper, reliability (HCI, NBTI) and device performance of nano-scale CMOSFETs with different channel stress were investigated. It was shown that NMOS and PMOS performances were improved by tensile and compressive stress, respectively, as well known. It is shown that improved device performance is attributed to the increased mobility of electrons or holes in the channel region. However, reliability characteristics showed different dependence on the channel stress. Both of NMOS and PMOS showed improved hot carrier lifetime for compressive channel stress. NBTI of PMOS also showed improvement for compressive stress. It is shown that $N_{it}$ generation at the interface of $Si/SiO_2$ has a great effect on the reliability. It is also shown that generation of positive fixed charge has an effect in the NBTI. Therefore, reliability as well as device performance should be considered in developing strained-silicon MOSFET.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.51-63
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• 2013

Recently with base apply MANET with the application for the service discovery and delivery which are various techniques are being proposed the result of such MANET base research techniques from actual inside. This dissertation proposes T-Chord(Trustworthy-based Chord) Ring system for MANET to guarantees from such requirements. T-Chord Ring system in order to manage Efficiently the services which the mobile nodes provide is the service discovery system which uses P2P overlay network Technique in mobile environment. The system which is proposed MANET communications in order to accomplish a service discovery operation with physical network class and logical network class will be able to minimize problems from about MANET service discoveries, and uses the dispersive hash table technique for a service discovery and effectiveness of service discovery improves and will be able to guarantee the expandability of network size. The mobile nodes(mobile device) have a mobility from MANET and operate with service request node, service provide node and service transmit node. The mobile nodes will be able to elect cluster header using Trustworthy that was evaluated service request, provision and delivery in each other. The system which is proposed a service discovery and a delivery efficiently will compose the cluster head which will grow of P2P overlay networks and will be able to accomplish. The system which proposes from dissertation is composed of Trustworthy evaluations of MANET mobile nodes, service information collection which is dispersed and P2P overlay networks that composed of Chord algorithm modules which provide O(Log N) efficiencies. The system comparison evaluation analyzes an efficiency from the expandability side of effectiveness and the network of service discovery technique and the service discovery message over head, service discovery and delivery of former times and service discovery and delivery is excellent gives proof from MANET.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.459-466
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• 2007

To analyze the water characteristics in the dry and wet seasons, the data for temperature, salinity, nutrients and $chl-{\alpha}$ were used, which were observed in the south coastal area of Korea during April to October 2000. At Yeosu in the south coast of Korea, the higher values of 35.0 psu in salinity were shown in March and April, the lower values of 23.0 psu in salinity were shown in August and September. The annual range of salinity was 12.0 psu. The total amount of precipitation in the wet season (July to October) was occupied 68% (about 846 mm) during 2000. The precipitation of the dry season (November to June) was occupied 32% (about 394 mm) in the year In the coastal area, the salinity variation is distinct in the period of July to October. Based on this result, we divided the season into two parts: the dry season during April to June and the wet season during July to October. Factor analysis was shown that temperature has strong negative relation and nutrients show positive relations in the dry season by the factor 1, which explains the total valiance of 50.6% at the surface water. In the wet season, salinity has negative relation and nutrients show positive relation by the factor 2, which explains the total variance of 33.5%. The bottom layer also showed similar to those of surface water in the results of factor analysis. These mean that nutrients become rich due to the freshwater inflow in the wet season. The low saline water is shown not only in the south coast but also in the overall region in the South Sea of Korea. It is suggested that the South Sea of Korea may call a ROFI (Region of Freshwater Influence) system in summer.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1477-1485
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• 2012

This study examined urbanization effects and the causes of urbanization, urban population growth, increase of the city scale, land cover change, and human cultures and economic activities, using the daily minimum temperatures of the past 50 years (1961-2010) with the subject of Busan and analyzed correlations between urbanization effects and the causes of urbanization. Thereby, this paper drew a conclusion as below: 1) Due to the urbanization effects, the average annual daily minimum temperature increased as about $1.2^{\circ}C$; however, except for the factor of urbanization, the increase was shown as about $0.2^{\circ}C$. The occupancy of urbanization effects in the total temperature increase was quite high as about 83%. 2) Just like other cities experiencing urbanization, Busan, too, sees population growth and the expansion of city area as well as increased urbanization effects. First of all, correlation between population growth and urbanization effect was high as 0.96 before 1985 while it was lowered as 0.19 after 1985. Also, correlation between the increase of city area and urbanization effect was high as 0.64 and 0.79 before and after 1985. 3) Regarding the correlation between long-term land use change and urbanization effect, urbanization effect was affected greatly by the increase of city area (0.97) and reduction of green area (0.92). 4) Concerning human activities possible to affect the climatic factors of a city, this paper found the following factors: road length, car increase, power use, and the consumer price index, etc. And regarding the correlation between the three factors and urbanization effect, the correlation was higher in the consumer price index (0.97), the number of registered cars (0.89), power use (0.75), and road length (0.58) in order.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1220-1225
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• 2012

Ligularia stenocephala leaves were subjected to extraction by using several solvents with different polarities, which were then investigated for their antioxidant and antimicrobial activities. Extraction yield of ethanol extract of Ligularia stenocephala was 21.36%. The water fraction showed the highest extraction yield of 60.35%, followed by the n-butanol, n-hexane, and ethyl acetate fractions. Total polyphenolic content was the highest (254.00 mg/g GAE) in the ethyl acetate fraction of Ligularia stenocephala extract. The ethyl acetate fraction had $IC_{50}$ values of 0.28 mg/mL for DPPH radical scavenging, and 96.$67{\pm}0.09%$ for ABTS radical scavenging activity. Further, FRAP value was significantly higher in the ethyl acetate fraction. The ethyl acetate fraction showed antimicrobial activities against B. cereus, and the diameter of the zone of inhibition was 10.2 mm at 5 mg/disc. These results suggest that the ethyl acetate fraction of Ligularia stenocephala possesses the antimicrobial activities against B. cereus, and its high antioxidant activity could be applicable to food additives and as a natural cosmetic ingredient.