• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1433-1436
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• 2003

A new method for the simultaneous determination of heavy metal ions in cigarette material by microwave digestion and reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed. The cigarette material was digested by microwave digestion. Lead, cadmium, mercury, nickel and tin ions in the digested samples were pre-column derivatized with tetra-(2-chlorophenyl)-porphyrin ($T_2$-CPP) to form color chelates, which were then enriched by solid phase extraction with a $C_{18}$ cartridge. The chelates were separated on a Waters Xterra$^{TM}RP_{18}$ column by gradient elution with methanol (containing 0.05 mol/L pyrrolidine-aceticacid buffer salt, pH = 10.0) and acetone (containin0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0)as mobile phase at a flow rate of 0.5mL/min and analyzed with a photodiode array detector from 350-600 nm. The detection limits of lead, cadmium, mercury, nickel and tin were 4,3,3,8 and 5 ng/L, respectively, in the original samples. This method was afforded good results.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.725-733
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• 2007

The contents of five heavy metals such as lead, cadmium, zinc, copper and manganese in soil and vegetables collected from four sites in Busan district with composite sampling method were determined with ICP emission spectrometer. The ranges of their contents in soil were lead, $1.65\sim4.36ppm;$ cadmium, $0.05\sim0.09ppm;$ zinc, $6.33\sim11.09ppm;$ copper, $0.44\sim1.35ppm;$ manganese, $8.40\sim19.39ppm$, respectively. These contents were lower than the Clarke number. The range of heavy metal contents in four vegetables such as lettuce, radish and its roots, spinach and cabbage were lead, $0.09\sim0.48ppm;$ cadmium, $0.01\sim0.08ppm;$ zinc, $1.81\sim14.62ppm;$ copper, $0.14\sim1.87ppm;$ manganese, $0.71\sim14.5$ 5ppm with the order of Zn(7.30 ppm)>Mn(4.35 ppm)>Cu(0.53 ppm)>Pb(0.19 ppm)>Cd(0.04 ppm) in average contents. The average transfer ratio of metals from soil to vegetables was order of Zn(77.8 %)> Cd(37.5 %)>Cu(34.5 %)>Mn(18.6 %)>Pb(6.7 %). In case of the same cultivating soil, the transfer ratio could be expected to the order of spinach$lettuce{\approx}cabbage$

• Resources Recycling
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• v.30 no.5
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• pp.3-9
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• 2021

In Korea, base metals such as lead, zinc, copper, tin, nickel, and aluminum have a polarized supply and demand structure. Despite the presence of world-class producers of lead, zinc, and copper, and their production is insufficient. And there are no domestic producers of tin, nickel, and aluminum, Thus, most of the domestic demand is dependent on imports. Therefore, it is necessary to prepare for the risk of supply interruption, such as the disruption of the import of base metals or interruption of domestic production. In this study, we estimated the quantity required to respond to the risk of import disruption, the quantity to which the market can respond, and the quantity to which the government needs to respond for six base metals (copper, lead, zinc, aluminum, nickel, and tin).

• Proceedings of the Korea Water Resources Association Conference
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• 1992.07a
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• pp.325-328
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• 1992

The purpose of this research is to develop the technique of heavy metal removal from wastewater. The research is divided into two parts, one part uses complex precipitation and the other uses adsorption. In the first part of the study, humic acid is used as the complex agent, humic acid is a polyelectrolyte with a high complexation affinity. Lead, copper, zinc and cadmium were studied for their complex precipitation efficiencies. In the batch studies, humic acid was effective in removing 100% of the lead and 48.2% of the copper respectively from wastewater without anytreatment. The efficiency of cadmium and zinc, however, was very low. In the second part of the study, wastewater is introduced at the top of a silicagel adsorption column and then bottom effluent concentration is analyzed. The results of the analysis are used to draw a breakthrough curve.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3313-3318
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• 2014

The reaction mechanism of Lead ions catalyzing complexation reactions between TIPP and metal ions was investigated by researching the kinetics of the formation of metalloporphyrins by UV/Vis-spectra, and verified by exploring the formation of metalloporphyrins catalyzed by acetic acid. Kinetics studies suggested that the fluctuations of reaction rate indicated the formation of metalloporphyrin was step-wise, including the pre-equilibrium step (the coordination of the pyrrolenine nitrogens to $Mn^+$) and the rate-controlling step (the deprotonation of the pyrrole proton). In the pre-equalization step, a sitting-atop (SAT) structure formed first with the complexation between larger radius of $Pb^{2+}$ and TIPP, changed the activation, then $Pb^{2+}$ left with the smaller radius of metal ions attacking from the back of the porphyrin ring center. In the rate-controlling step, two pyrrole protons dissociated to restore a stable structure. This was verified by adding acetic acid at different reaction times.

• Transactions of Materials Processing
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• v.23 no.4
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• pp.206-210
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• 2014

The metal lead frame, a semiconductor component, has product tolerances in micro units as compared to products made with a larger size mold. Therefore, small deflections of the mold and of the press as well as the press molding process itself have a strong influence on accuracy of the product. Hence, it is necessary for the process design to consider the structural response of the mold and the press during deformation. In the current study, the mold deflection and pressure on the punch is examined using the finite element modeling (FEM) program ABAQUS. The results from the simulation were verified with the dynamic deformation measurement equipment using digital image correlation (DIC).

• Korean Journal of Organic Agriculture
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• v.9 no.3
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• pp.85-92
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• 2001

The effect of Dolichos lablab leave extract on enzyme activities in mice blood was investigated in this study to clarify the new useful application of the Plant leaves. There were not significant differences in the enzyme activities in mice blood among treatment fed with the leave extract and non fed control. The feeding treatment with the extract showed a tendency to activity compared to the nun fed control. The activities of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and lactate dehydrogenase in mice blood at the treatment fed with lead and the leave extract were significantly low compared to their activities at the non fed treatment with the extract, respectively. The choline esterase activity was high at the leave extract feeding. The cadmium dietary treatment showed the same result as the lead treatment. In conclusion, the physiological function of the Jebikong leave was significantly in creased when the mice was stressed by the hear metal intake. Therefore, the plant leave extract would consider the reduction of heart metal effect.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.118-122
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• 2017

Bacterial growth inhibition by lead, zinc and cadmium was measured by using modified Tris minimal medium. The toxicity against Escherichia coli strain was in the order of zinc> cadmium> lead, and the Escherichia coli strain overexpressing iron-containing superoxide dismutase 2 of Streptomyces coelicolor A3(2) was found to have resistance to heavy metals.

• Journal of Nutrition and Health
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• v.44 no.6
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• pp.518-526
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• 2011

To determine blood heavy metal concentrations by seafood consumption in Korean adults, blood cadmium, mercury, and lead concentrations in a representative sample of 1,709 Koreans participated in the Fourth Korea National Health and Nutrition Examination Survey (KHANES IV-2) in 2008 were analyzed by age and seafood consumption frequency. The mean blood cadmium, mercury, and lead concentrations were $1.14{\pm}0.73{\mu}g/L$, $5.50{\pm}3.83{\mu}g/L$, and $2.56{\pm}1.22{\mu}g/dL$, respectively. The subjects aged ${\geq}$ 50 years had significantly higher blood cadmium concentrations than the subjects aged 20~39 years. Blood mercury concentrations of the 50's were significantly higher than those of the 20's and 30's (p < 0.05). Approximately, 43% of males and 22% of females had blood mercury concentrations > $5.8{\mu}g/L$ which is a blood mercury level equivalent to the current Reference Dose. Only 2 subjects had lead concentrations > $10{\mu}g/dL$, the standard lead level by the Centers for Disease Control and Prevention, USA. The subjects consuming pollack, mackerel, anchovy, corvina, shellfish, and salted seafood at least once a week had significantly higher mercury concentrations than the subjects consuming those seafoods less than once a month. However, there were no clear relationships between blood cadmium and lead concentrations and seafood consumption frequencies.

• The Journal of Natural Sciences
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• v.5 no.2
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• pp.19-24
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• 1992

To find out the extent of air pollution in Taejon city, we investigated the concents of heavy metals in barks of trees in principal roadside, the outer block of a roadside and Pomunsan Park. Among the road-side trees in these areas, Platanus orientalis, Ginkgo biloba and Liriodendron tulipifera have been chosen. And we analyzed the relationship between the content of heavy metal of the barks and the traffic volume expressed by cars passing through for an hour. The range of contents of the lead in barks of the trees in the roadside and Pomunsan Park were respectively 2-1109 ppm and 5-11 ppm. Generally the contents of lead of barks of the trees in roadside was much higher than that in Pomunsan Park. And there has been positive correlation between the traf-fic volume and the content of lead in the barks. The more cars passing through for an hour, the higher the maximum in contents of lead in the barks of roadside trees. By the way the contents of cadmium in barks of the roadside trees was slightly higher than that in Pomunsan Park and was little variable.