• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.72-78
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• 1984

The water quality and the budget of pollutant loading in the downstream of Nakdong River were surveyed at 3 sites along the main stream from Mulgum to Hadan and 1 site of Yangsan tributary with response to the tides in May and June, 1983. The level of TSS in the Yangsan tributary, 6.1~21.3mg/l, was higher than any other site. The mean values of BOD were 1.16mg/l at Mulgum site, 1.83mg/l Yangsan site, 0.79mg/l Hwamyeong site and 3.56mg/l at Hadan site. The levels of NH sub(4) super(+)-N and PO sub(4) super(3-)-P were the highest at Hadan site, and the levels of zinc and copper were 2.11~5.98ppb and ND-50.00ppb at Yangsan tributary site. Although the flow rate of Yangsan stream accounted for only 4% of that of main stream, but the mean value of pollutant loading in the Yangsan stream amounted to 8.3% of the that of main steam.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.79-84
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• 2010

Formation of TSV (Through-Si-Via) with an Au seed layer and Cu filling to the via, simplification of bumping process for three dimensional stacking of Si dice were investigated. In order to produce the via holes, the Si wafer was etched by a DRIE (Deep Reactive Ion Etching) process using $SF_6$ and $C_4F_8$ plasmas alternately. The vias were 40 ${\mu}m$ in diameter, 80 ${\mu}m$ in depth, and were produced by etching for 1.92 ks. On the via side wall, a dielectric layer of $SiO_2$ was formed by thermal oxidation, and an adhesion layer of Ti, and a seed layer of Au were applied by sputtering. Electroplating with pulsed DC was applied to fill the via holes with Cu. The plating condition was at a forward pulse current density of 1000 mA/$dm^2$ for 5 s and a reverse pulse current density of 190 mA/$dm^2$ for 25 s. By using these parameters, sound Cu filling was obtained in the vias with a total plating time of 57.6 ks. Sn bumping was performed on the Cu plugs without lithography process. The bumps were produced on the Si die successfully by the simplified process without serious defect.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.117-129
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• 2002

Concentration of welding fumes and their components is known to be hazardous to welder and adjacent worker. To determine the generation rates of metals in fumes, $CO_2$ flux cored arc welding on stainless steel was performed in well designed fume collection chamber. Variables were different products of flux cored wire(2 domestic products and 4 foreign products) and input energy(low-, optimal- , high input energy). Mass of welding fumes was determined by gravimetric method(NIOSH 0500 method), and 17 metals were analysed by inductively coupled plasm-atomic emission spectroscopy(NIOSH 7300 method). Flux cored wire tube and flux were analysed by scanning electron microscopy to determine their metal composition. 17 metals were classified by their generation rates. Generation rates of iron, manganese, potassium and sodium were all above 50mg/min at optimal input energy level. Generation rates of chromium and amorphous silica were 25~50mg/min. At 1~25mg/min level, nickel, titanium, molybdenum, and aluminum were included. Copper, zinc, calcium, lead, magnesium, lithium, and cobalt were generated below 1 mg/min. Generation rates of metal components in fumes were influenced by input energy, types of flux cored wire. Flux cored wire was consisted of outer shell tube and inner flux. Iron, chromium, and nickel were the major components of outer tube. Flux contained iron, chromium, nickel, potassium, sodium, silica, and manganese. The use of flux cored wire can increase the hazards by increasing the amounts of fumes formed relative to that of solid wire. The reason might be the direct transfer of elements from the flux, since the flux is fine power. Ratio of metals to the fume of flux cored wire was lower than that of solid wire because non-metal components of flux were transferred. Total metal content of fumes in flux cored arc welding was 47.4(24.3~57.2) percent that is much lower than that of solid wire, 75.9 percent. We found that generation rates of iron, manganese, chromium and nickel, all well known to cause work related disease to welder, increased more rapidly with increasing input energy than those of fumes. To reduce worker exposure to fumes and hazardous component at source, further research is needed to develop new welding filler materials that decrease both the amount of fumes and hazardous components.

• Journal of Environmental Health Sciences
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• v.43 no.2
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• pp.103-110
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• 2017

Objectives: This study was performed to provide basic data for the re-establishment of standards (criteria) and analytical methods for hazardous metals in nail enamel. Methods: Ten metals (lead; Pb, arsenic; As, cadminum; Cd, antimony: Sb, cobalt; Co, nikel; Ni, copper; Cu, chromium; Cr, aluminum; Al, and mercury; Hg) were measured in 67 commercial nail enamels containing glitter and/or pearls. The content of hazardous metals (excepting Hg) was determined by using an inductively coupled plasma-optical emission spectrophotometer (ICP-OES) after microwave digestion. Mercury content was measured by a mercury analyzer without any preparation. Results: The detected ranges of the intact samples were as follows: $ND-1.756{\mu}g/g$ for Pb, $ND-1.24{\mu}g/g$ for As, ND for Cd, $ND-20.41{\mu}g/g$ for Sb, $ND-12.36{\mu}g/g$ for Co, $ND-7.908{\mu}g/g$ for Ni, $0.088-79.27{\mu}g/g$ for Cu, $0.281-18.54{\mu}g/g$ for Cr, $13.78-3563{\mu}g/g$ for Al, and $ND-0.044{\mu}g/g$ for Hg. After centrifugation, the detected ranges of supernatant were as follows: $ND-0.435{\mu}g/g$ for Pb, $ND-0.504{\mu}g/g$ for As, ND for Cd, $ND-0.035{\mu}g/g$ for Sb, $ND-13.17{\mu}g/g$ for Co, $ND-0.232{\mu}g/g$ for Ni, $0.117-90.07{\mu}g/g$ for Cu, $0.174-2.787{\mu}g/g$ for Cr, and $9.459-1565{\mu}g/g$ for Al. The results of this analysis showed that the levels of heavy metals such as Pb, As, and Sb were much higher in the intact samples than those of supernatant. Conclusion: In the present study, we found that the levels of hazardous metals were significantly different depending on the status of the presence of glitter. Based on the results, we recommend that the product consumer refrain from prolonged application of nail enamel, avoid biting or chewing the nails, and wear gloves during cooking and washing dishes.

• 한국생태학회:학술대회논문집
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• 2002.08a
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• pp.119-125
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• 2002

Application of phytoremediation in the polluted area to remove undesirable materials is a complex and difficult subject without detailed investigation and experimentation. We investigated the accumulation patterns of cadmium and lead in plants naturally grown, the bioavailability of plants to accumulate these toxic metals and the responses of P. thunbergii to cadmium and lead. The soil samples contained detectable lead (<17.5$\mu\textrm{g}$/g), whereas cadmium was not detected in the soils of study area. The whole body of Persicaria thunbergii contained detectable lead (<320.8$\mu\textrm{g}$/g) but cadmium was detected only in the stem (<7.4$\mu\textrm{g}$/g) and root (<10.4$\mu\textrm{g}$/g) of P. thunbergii. Cadmium was not detected in Trapa japonica and Nymphoides peltata, whereas lead was detected in T. japonica (<323.7$\mu\textrm{g}$/g) and N. peltata (<177.5$\mu\textrm{g}$/g). Correlation coefficient between lead content in soil and in these plant samples represented positive correlation. The total content of lead in each plant sample increased in the order of N.peltata$\leq$P.thunbergii

• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.7-15
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• 2018

The friction factors according to the flow regimes in helical coil tubes depend on the coil diameter, the tube diameter, and the coil pitch. In previous studies, correlations for the laminar flow regime in helical coil tubes have been proposed. However, studies on the transition flow regime and the turbulent flow regime are insufficient and further researches are necessary. In this study, characteristics of the friction factors for the laminar, transition and turbulent flow regimes in helical coil tubes were experimentally investigated. The helical coil tubes used in the experiments were made of copper. The curvature ratios of the helical coil tubes, which means the ratio of helical coil diameter to inner diameter of the helical coil tube are 24.5 and 90.9. Experiments were carried out in the range of $529{\leq}Re{\leq}39,406$ to observe the flows from the laminar to the turbulent regime. The friction factors were obtained by measuring the differential pressures according to the flow rates in the helical coil tubes while varying the curvature ratios of the helical coil tubes. Experimental data show that the friction factors for the helical coil tube with 24.5 in the curvature ratio of the helical coil tube were larger than those in the straight tube in all flow regimes. As the curvature ratio of the helical coil tube increases, the friction factor in turbulent flow regime tends to be equal to that of the straight tube. In addition, it was confirmed that the transition flow regimes in the helical coil tubes were much wider than those in the straight tube, also the critical Reynolds numbers were larger than those in the straight tube. The results obtained in this experimental study can be used as basic data for studies on the water hammer phenomenon in helical coil tubes.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2057-2061
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• 2012

Backgrounds: Deficiency or excess of trace elements can induce body metabolic disorders and cellular growth disturbance, even mutation and cancerization. Since there are few studies of the effect of trace elements in bladder carcinoma in China, the aim of this study was thus to assess variation using a case control approach. Methods: To determine this, 81 patients with bladder carcinoma chosen as a study group and 130 healthy persons chosen as a control group were all assayed for urinary and serum trace elements (calcium [Ca], zinc [Zn], copper [Cu], selenium [Se]) using an atomic absorption spectrophotometer, and the results were analyzed by independent sample t tests. The correlative factors on questionnaires answered by all persons were analyzed by logistic regression. Results: The results showed urinary Ca, Zn and serum Cu levels of the study group to be significantly higher (P<0.05) than those of he control group. Serum Ca and Se levels of study group were significantly lower (P<0.05) than those of control group. Conclusion: There were higher urinary Zn and serum Cu concentrations in bladder carcinoma cases. Bladder carcinoma may be associated with Ca metabolic disorder, leading to higher urinary Ca and lower serum Ca. Low serum Se and smoking appear to be other risk factors for bladder carcinoma in China.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.60-81
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• 2020

This research was trying to examine through the technology acceptance model that is expanded in order to make an inquiry the factors having an effect on the acceptance intention of the technology fusion type webtoon user. The survey was carried out for the research for 114 questionnaire respondents where there is the technology fusion type webtoon utilization experience. After and hierarchical regression analysis was performed and the relationship was analyze between the factor. The total 13 hypotheses and one research problems were set and the study with was proceeded. Next, it is same if the results of study is summarized. Firstly, the interactivity and immersion, that is the subordinate factor of the Siljaegam, affected the static influence to the perceived usability. Secondly, with having the static influence an effect on the technology fusion type webtoon use intention the perceived usability was confirmed. Thirdly, the effeciency, Tendency of Conciseness, and consistency were the technology fusion type GUI standard extracted with the Ttamsaekjeok the result subfactor that it analize factor. Finally, with giving the meaningful influence to the perceived easiness the visual unrefined copper steam, that is the subordinate factor of the Siljaegam, was confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.600-613
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• 2018

The purpose of this research was to introduce a network analysis method for analyzing the recent trend of the flexible solar cell using a scholarly database. Based on the five years from 2013 to 2017, we used centrality analysis of research papers via measurement of degree centrality, closeness centrality, and betweenness centrality. The results of network analysis show that cell has a centrality value above 0.8, which means that cell is connected with 80% of the total keywords, so it is recognized as the center of flexible solar cell research. The analysis results also indicate that perovskite and copper indium gallium diselenide (CuInGaSe2, or CIGS) are the center of the subgroup for cell. We recognize that the result refers to recent new technology called the CIGS/perovskite tandem solar cell. We hope that the network analysis method will be the appropriate and precise tool for technology and research planning via elaboration and optimization.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1114-1121
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• 2016

This study investigated the food components and antioxidant activities of dried Jerusalem artichoke (Helianthus tuberosus L.) with white and purple colors. For the proximate composition of dried Jerusalem artichoke, regardless of color, carbohydrate content was highest, followed by crude protein, ash, and moisture contents, and breed-specific differences were not detected. The highest mineral content of dried Jerusalem artichoke was potassium, followed by calcium, magnesium, sodium, and iron. The major minerals of white color sample were calcium, magnesium, and zinc, whereas those of the purple color sample were potassium, sodium, copper, and manganese, and no significant differences between the samples were detected. The main amino acid of dried Jerusalem artichoke was arginine, regardless of color, followed by asparagine, aspartic acid, and ${\gamma}-amino-n-butyric$ acid in order. Cysteine, leucine, and tyrosine were significantly (P<0.05) more abundant in the purple color sample than in the white color sample. In contrast, phosphoethanolamine was significantly (P<0.05) higher in the white color sample than in the purple color sample. Antioxidant activity was higher in the purple color sample than in the white color sample for all activities except the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay methodology. Ferric-reducing antioxidant power and oxygen radical absorbance capacity assays at low concentrations of extracts found no differences between the two samples, although the purple sample at high concentration showed relatively high antioxidant activities.