• Environmental Analysis Health and Toxicology
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• v.25 no.1
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• pp.27-40
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• 2010

The current study was designed to scientifically evaluate the atmospheric particulate pollution in residences relative to their proximity to a Korean major iron/metal industrial complex (IMIC). This objective was achieved by measuring the concentrations and elemental composition of particulate matter with aerodynamic diameters equal to or less than 10 ${\mu}m$(PM10) in industrial ambient air from IMIC and residential ambient air with relative proximities to IMIC. The trace metals were analyzed using an inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The industrial mean values exceeded the Korean year/70-${\mu}g/m^3$ standard for PM10, whereas the residential mean values did not. However, the maximum residential values did exceed or were close to the Korean PM10 year standard. For individual elements, the ambient concentrations ranged widely from values in the order of a few $ng/m^3$ to thousands of $ng/m^3$. The residential mean mass concentrations in the PM10 measured in the present study were higher than or similar to those reported in earlier studies. This study suggests that residents in neighborhoods near the IMIC are exposedto elevated particulate levels compared to residents living further away from such a source.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.903-908
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• 2006

Various extraction procedures were investigated using reference materials and samples to evaluate extraction efficiency and effectiveness. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure total arsenic and to quantitate arsenic species when coupled to an HPLC (high pressure liquid chromatography). Arsenic species were extracted from rice flour (NIST SRM 1568a) with water/methanol mixtures using accelerated solvent extraction (ASE). Total arsenic extraction efficiency ranged from 42 to 64%, for water and various methanol concentrations. From spinach (NIST SRM 1570), freeze-dried apple, and rice flour (NIST SRM 1568a), arsenic species were extracted with trifluoroacetic acid (TFA) at 100 ${^{\circ}C}$. Total arsenic extraction efficiency was 90% for spinach, 75% for freeze-dried apple, and 83% for rice flour. Enzymatic extraction with alpha-amylase and sonication resulted in extraction efficiency of 104% for rice flour, 98% for freeze-dried apple, and 7% for spinach. Chromatograms of arsenic species extracted by the optimum extraction methods were obtained, and the species were quantified. Arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) were found in the apple sample, and DMA and As(V) in the rice flour sample. As(V) and MMA were found in three herbal dietary supplement samples.

• Journal of the Korean Society for Heat Treatment
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• v.27 no.1
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• pp.10-14
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• 2014

Niobium nitride coatings have many potential thin film applications due to their chemical inertness, good mechanical properties, temperature stability and superconducting properties. In this study, $NbN_x$ coatings were prepared by inductively coupled plasma (ICP) assisted DC magnetron sputtering method on the surface of AISI 304 austenitic stainless steels. Effects of target power were studied on mechanical and chemical properties of the coatings. The coating structure was analyzed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The coating hardness was measured by micro-knoop hardness tester. The coating thickness was measured using a 3D profiler and wear characteristics were estimated using a ball-on-disk wear tester. The thickness of the $NbN_x$ coatings increased linearly from 300 nm to 2000 nm as the Nb target power increased, and it showed over $HK_{0.005}$ 4000 hardness above Nb target power of 300 W. Hexagonal ${\delta}^{\prime}$-NbN phase and cubic ${\delta}$-NbN phase were observed in the coating films and the hardness of the NbNx coatings was higher when these two peaks were mixed. The corrosion resistance increased with the increase of the Nb target power.

• Journal of Korean Neurosurgical Society
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• v.30 no.3
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• pp.366-370
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• 2001

Objective : The authors present three cases of brain tumors in which epidural hematomas(EDHs) were developed postoperatively in the remote areas from craniotomy sites. The preventive tactics as well as possible mechanisms of development of remote EDH are discussed. Material and Methods : The magnetic resonance imagings of three patients revealed a left lateral ventricular mass located just aside of foramen Monro in a 27-year-old male, a large cystic mass in the temporal lobe in a 35-year-old male, and a partially calcified pineal mass in a 27-year-old male patient. The surgical removals of these tumors were performed without any noticeable events during surgery via left frontal transcortical transventricular approach for lateral ventricular tumor, left temporal craniotomy for cystic temporal tumor, and right occipital transtentorial approach for pineal tumor. Results : Postoperative EDHs remote from the sites of craniotomy were detected by the immediate postoperative computerized tomographic scans. We obtained good outcomes without any morbidity in all three patients with emergent evacuation of the hematoma. The pathologic diagnoses were lateral ventricular ependymoastrocytoma, temporal craniopharyngioma and mixed germinoma of the pineal region. Conclusion : It is postulated that a sudden reduction of intracranial pressure(ICP) at the time of tumor removal may strip the dura from the inner table of the skull to cause EDH from the remote site of craniotomy. Gradual reduction of ICP with slow drainage of cerebrospinal fluid before tumor removal as well as lowering the head position of patient during surgery might be helpful for preventing this unusual complication.

• Analytical Science and Technology
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• v.21 no.2
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• pp.135-142
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• 2008

Plasticizer and heavy metals in domestic PVC wallpaper manufactured in Korea after 2005 were analyzed to identify the contained quantity in comparison with the 2002 manufactured PVC wallpapers. Plasticizer of wallpapers was analyzed by the method KSM1991 which uses soxhlet extraction with n-hexane and GC/FID. Heavy metals were pre-treated with 0.07 mol/L hydrochloric acid (HCl) and analyzed by ICP/OES according to the EN 71-part 3 method. DEHP, DINP, DEP, acetyl tributyl citrate were identified from wallpaper. Contents of DEHP, DINP were 0.2~11.3%, 17.9~27.8% respectively in 6 wallpapers, DEP and acetyl tributyl citrate were 1.5%, 8.9% respectively in one wallpaper. Plasticizers have changed from DEHP that has possibility of hazards to DINP, DEP and acetyl tributyl citrate as compared with 2002. Heavy metals were detected under guide line from all of the wallpapers except fire-retardant wallpaper contain antimony. While PVC wallpaper was improved by use of various plasticizer, functional wallpapers such as fire-resistant wallpaper contain high antimony in this study.

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.373-375
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• 2006

$CF_4$ gas is one of the most common chemicals used for dry etching in semiconductor manufacturing processes. For application to the etching process and environmental control, the low-pressure inductively coupled plasma (LP-ICP) was employed to obtain the spectrum of $CF_4$ gas. In terms of the analysis of the spectra, trace CF radical by A-X and B-X transitions was detected. The other $CF_x$ radicals, such as $CF_2$ and $CF_3$, were not seen in this experiment whereas strong C and $C_2$ emissions, dissociation products of $CF_4$ gas, were observed.

• Applied Science and Convergence Technology
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• v.27 no.1
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• pp.14-18
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• 2018

In order to understand the mechanism of the synthesis of particles using a plasma torch, it is necessary to understand the reaction mechanisms using a computer simulation. In this study, we have developed a simulation method to combine the Lagrangian scheme to follow microparticles and a nodal method to treat nanoparticles categorized with different particle sizes. The Lagrangian scheme includes the Coulomb force which affects the dynamics of larger particles. In contrast, the nodal method is adequate for the nanoparticles because the charge effect is negligible for nanoparticles but the number of nanoparticles is much larger than that of microparticles. This method is helpful to understand the dynamics and growth mechanism of micro- and nano-powder mixture observed in the experiment.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.515-521
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• 2010

In this research, we were prepared the glazed ceramic samples by the change of the pigment content and investigated to reveal the standardized color. The chemical composition of the pigment was analyzed using a ICP-OES. XRF mapping and UV-Vis spectroscopy were used to evaluate the color property and surface homogeneity. The color development was observed as a result of analyzing the pigment content and change of the color. The pigment content and the spectral reflection showed the relation of the inverse proportion and the standardized color which could be revealed through analysis data.

• The Korean Journal of Food And Nutrition
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• v.12 no.4
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• pp.344-349
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• 1999

The mineral contents were analyzed for apple juices by Inductively Coupled Plasma. The Mg contents of tested commercial apple juices ranged 6.27∼32.91ppm, Ca 15,95∼3.11.76ppm K231∼1148.02ppm Na 39.82∼115.68ppm and P 19.27∼304.02ppm. The mineal contents of model apple juice were Mg 29.83∼45.65ppm Ca 16.98∼30.98ppm K 814.28∼1,256.70ppm Na 19.88∼26.85ppm and P 25.88∼54.71ppm. respectively. Comparing mineral contents of model apple juices and commercial apple juice, Na, Ca and P contents of commercial apple juices were higher but Mg, K contents were lower than that of model apple juices. Among the mineral content of apple juices. K was the major element.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.456-460
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• 2012

This study was carried out as a survey on the level of lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) in 5 items of agricultural products (lettuce, pumpkin, head lettuce, cabbage and crown daisy) for which safety guidelines are not yet established in Korea. The 407 samples were collected from local markets in 9 regional places and the levels of metals were measured by ICP-MS and mercury analyzer. The average levels of Pb, Cd, As and Hg were 0.026, 0.018, 0.008 and 0.003 mg/kg for lettuce, 0.002, 0.001, 0.001 and 0.0006 mg/kg for pumpkin, 0.002, 0.005, 0.001 and 0.0005 mg/kg for head lettuce, 0.001, 0.002, 0.0002 and 0.0006 mg/kg for cabbage and 0.022, 0.014, 0.006 and 0.004 mg/kg for crown daisy. For risk assessment, the daily dietary exposures of Pb, Cd and Hg by intake of these agricultural products were calculated and compared with PTWI (provisional tolerable weekly intake) established by JECFA. The daily dietary exposure of heavy metals by intake of these agricultural products were 0.13, 0.56 and 0.09% of PTWI, respectively. These monitoring results will be utilized as fundamental data for the establishment of Korean standards of Pb, Cd, As and Hg in 5 items of agricultural products and valuable source for DB construction for science-based safety control of heavy metals in foods including agricultural products.