• Journal of Environmental Health Sciences
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• v.33 no.6
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• pp.479-487
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• 2007

[ $PM_{2.5}$ ], particulate matter less than 2.5 um in a diameter, can penetrate deeply into the lungs. Exposure to $PM_{2.5}$ has been associated with increased hospital visits for respiratory aliments as well as increase mortality. $PM_{2.5}$ is a byproduct of combustion processes and as such has a complex composition including a variety of metallic elements, inorganic and organic compounds as well as biogenic materials (microorganisms, proteins, etc). In this study, the average concentrations of fine particulates $PM_{2.5}$ have been measured simultaneously in Asan and Seoul, Korea, by using particulate matter portable sampler from September 2001 to August 2002. Sample collection filters were analyzed by ICP-OES to determine the concentrations of metallic elements (As, Ni, Fe, Cr, Cd, Cu, Pb, Zn, Si). Annual mean $PM_{2.5}$ concentrations in Asan and Seoul were 37.70 and $45.83\;{\mu}g/m^3$, respectively. The highest concentrations of $PM_{2.5}$ were found in spring season in both cities and the concentrations of measured metallic elements except As in Asan were higher than those in Seoul, suggesting that yellow dust in spring could affect $PM_{2.5}$ concentrations in Asan rather than Seoul. The correlation coefficients of Pb and Zn were 0.343 for Asan and 0.813 for Seoul during non-yellow dust condition, suggesting that Pb and Zn were influenced with the same sources. The correlation coefficients between Si and Fe in the fine particulate mode were 0.999 (Asan) and 0.998 (Seoul) during yellow dust condition. It was suggested that these two elements were impacted by soil-related transport from China during the yellow dust storm condition.

• Journal of the Korean Applied Science and Technology
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• v.29 no.4
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• pp.561-569
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• 2012

Study attempts to evaluate the environmental cost and benefit for management of particulate matters of Donghae harbor in Gangwondo. The level of fine dust suspended in the vicinity of the harbor was quite high, exceeding the national standard ($100{\mu}g/m^3$) depending on the places. The test field harbor deals with lots of limestone and coal, so that fine particulates could be generated while loading it and unloading. It was estimated that the direct handling of cargos might produce 12 tons of PM10(Particulate Matters of $10{\mu}m$) a year. In addition, heavy vehicles for transportation of various cargos including raw materials emit huge amount of diesel soots and cause to redispersion of road dust. The local government spends more than 2 billion won every year, and it contributes to reduce the atmospheric dust. According to the prediction of cost to benefit, it will present the effectiveness in 720 % maximum and at least 240 %.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.1
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• pp.81-92
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• 1993

A purpose of this study was carried out to investigate the concentrations of four elements of PAHs(Polycyclic Aromatic Hydrocarbons) in suspended particulate matters of underground shopping stores in Seoul city. The particulate matters were collected at five underground shopping stores(Yongdungpo, Myongdong, Ulchiro, Express Terminal, Chamshil) in the Seoul area during February-October, 1992. Samples were collected using cascade impactor of low volumn air sampler and were analysed using High Performance Liquid Chromatography(HPLC) with fluorescence detector. Calibration on HPLC analyse is nearly accord with retention time between the standard solution and the samples. Analysed results obtained favorable analysing recovery rate of 97.3% and coefficient of variation of 1.60%. Mean concentrations of suspended particulate matters in five underground shopping stores wre 216.3 g/$m^3$ and observed higher at fine particles(117.2 g/$m^3$) which is respirable particulates than coarse particles(99.2 g/$m^3$). Concentrations of four species PAH were determined with anthracene of 16.8ng/$m^3$, fluoranthene of 72.3ng/$m^3$, benzo(a)pyrene of 0.54ng/$m^3$, and benzo(k)fluoranthene of 0.29ng/$m^3$, respectively. Fluoranthene levels were significantly higher than those levels in other components. PAHs concen-tration at shopping areas showed 21.3ng/$m^3$ in Yongdungpo, 35.1ng/$m^3$ in Myongdong, 23.4ng/$m^3$ in Ulchiro, 11.1ng/$m^3$ in Express Terminal, and 21.4ng/$m^3$ in Chamshil, respectively. Particularly, benzo(a)pyrene and benzo(k)-fluoranthene were detected over 83 percentage in fine particles, while fluoranthene wre highly detected in coarse particles. Also, higher concentrations of benzo(a)pyrene, benzo(k)fluoranthene were found in winter while levels of anthracene and fluoranthene were found higher in summer than other seasons.

• Environmental Analysis Health and Toxicology
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• v.13 no.1_2
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• pp.43-53
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• 1998

Ambient air levels of polycyclic aromatic hydrocarbons(PAHs) are of concern because of their potential for adverse health effects including transformation of some of these substances to mutagens and carcinogens by mammalian microsomal enzyme system. Airbone particulate samples were collected by a conventional high-volume sampler and by an Anderson cascade impactor on 2 to 3 days in each month over a period of 1 year at a representative site of the heavy traffic area of Seoul from beptember 1994 to August 1995. Ten individual PAHs in sizable air particulates of each stage of two months were separated and analyzed by gas chromatography/mass spectrometry. As a results of analysis, the gross concentrations of PAHs in the fine and coarse particles were higher in the winter month than in the spring, followed in descending order by in the fall and summer. In a study of dependency of 10 PAHs compounds on size distribution of particles at heavy traffic area found that about 85% of the total PAHs content was associated with particles less than 2.0um (fine particles) in diameter of winter sampling period. while 79% were associated with this size fraction during summer period. In according to the mean concentrations of the 10 PAHs in 7 size classification from < 0.38 to> 10.1, the 'size was the smaller, PAHs concentration was the higher. Thus it was found that PAHs concentration was greatly affected by air particle size. Annual mean benzo(a)pyrene equivalents was 5.88ng/m$^3$ and obtained by applying, toxic equivalency factor developed by Nisbet and Lagoy.

• Journal of Korean Society for Atmospheric Environment
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• v.4 no.2
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• pp.57-66
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• 1988

Sandy dust phenomena was observed from April 19 to 23, 1988 in Seoul and suspended particulate was collected by Andersen air sampler during this period. The samples were analyzed for 16 components $(SO_n^{2-}, NO_3^-, Cl^-, PO_4^{3-}, NH_4^+, F^-, Al, Fe, K, Cu, Mn, Na, Pb, Mg, Ca, Cd)$. The conclusions are as follwes: 1. Total suspended particulate concentation during the period of sandy dust phenomena was 489 $\mug/m^3$ (ordinary times: 140-125 $mug/m^3$) 2. The water - soluble ion component concentration of suspended particulate during the period of sandy dust phenomena was few and the metal concentration of that was more than that of ordinary times. 3. The cumulative frequency distribution of suspended particulates in logarithmic diagram did not show similar to normal log distribution during the period of sandy dust phenomena. 4. $SO_4^{2-}, NO_3^-, Cl^-, and PO_4^{3-}$ was onsided to coarse particle, and $NH_4^+$ and F to fine particle in the size distribution of water - soluble ion components during the period of sandy dust phenomena. 5. Metal concentration was high and Al, Fe, Cu, Mn, Na, Mg, and Ca was onsided to coarse particle, and K, Pb, and Cd to fine particle in the size distribution of metal components. 6. During the period of sandy dust phenomena the quantity of respirable particle (< 1 $\mum$) was about 3 times and that of metal components were about 2 - 11 times than that of ordinary times. 7. The concentrations of $NO_3^-, Cl^-, NH_4^+$ at ordinary times were 1.1 - 4 time than that of the period of sandy dust phenomena.

• Clean Technology
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• v.7 no.1
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• pp.27-34
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• 2001

The waste slurry generated from CMP process contains particulate and heavy metals. It is hard to treat the waste slurry by conventional treatment method because the particulates in the waste are too fine to be easily separated the solid from the waste for the purpose of water recycling. The investigation was focused on finding the optimum condition of coagulation with two different coagulants. When the solid content in the waste slurry solution was 0.1wt%, the optimal ranges of pH and PACl concentration were 4~6 and 20~50 mg/L, respectively. When the solid content was increased to 0.5wt%, the optimal condition was 4~5 for pH and 50~100 mg/L for PACl concentration.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.129-136
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• 2006

Although cleaner and cheaper deinking of ONP could be performed at the neutral or low alkaline condition excessive loss from froth-flotation is unavoidable and so reduction of alkali or caustic soda dosage sacrifices recycling yield. Now the new trade-off regarding alkali dosage versus flotation yield is urgently required in order to set the optimized neutral or low alkaline deinking process of ONP. Lipase from Thermomyces Lanuginosus has an effect on desizing and deacetylation reaction and it could be applied to the stock of pre flotation secondary stage in order to reduce the flotation reject without the sacrifice of optical properties of flotation accepts. Instead of inorganic base, lipase could be applied as a biochemical catalyst for the selective modification of valuable hydrophobic particles in deinking stock, for example cellulose fines and inorganic fillers covered by hydrophobic additives or contaminants. When the enzymatic hydrolysis of ester bond could be made on the surface of hydrophobic particulates, unwanted float of fine particles could be prevented. Now the enhancement of flotation selectivity or the modification of the hydrophobicity of deinking stock is expected to be promoted by the enzymatic pre treatment. And the reduction of recycling cost with the saves of raw material, recovered paper would be possible as a result.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.437-450
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• 2004

Extensive forest fire activities occurred across the border in Russia, particularly east of Lake Baikal between the Amur and Lena rivers in May 2003. These forest fires released large amounts of particulates and gases into the atmosphere, resulting in adverse effects on regional air quality and the global radiation budget. Smoke pollution from the Russian fires near Lake Baikal was transported to Korea through Mongolia and eastern China. On 20 May 2003, a number of large fires were burning in eastern Russian, producing a thick, widespread pall of smoke over much of Northeast Asia. In this study, separation technique was used for aerosol retrieval application with imagery from MODIS aboard TERRA satellites. MODIS true-color image shows the location of fires and the grayish color of the smoke plumes over Northeast Asia. Aerosol optical thckness (AOT) retrieved from the MODIS data were compared with fire hot spots, ground-based radiation data and TOMS -based aerosol index data. Large AOT, 2.0-5.0 was observed on 20 May 2003 over Korea due to the influence of the long range transport of smoke aerosol plume from the Russian fires, while surface observed fine mode of aerosol size distribution increased.

• Journal of Korea Foundry Society
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• v.37 no.4
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• pp.115-122
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• 2017

The aim of this research is to evaluate the wear properties of (TiB+TiC) paticulate reinforced titanium matrix composites (TMCs) by in-situ synthesis. Different particle sizes (1500, $150{\mu}m$) and contents (0.94, 1.88 and 3.76 mass% for Ti, 1.98 and 3.96 mass% for the Ti6Al4V alloy) of boron carbide were added to pure titanium and to a Ti6Al4V alloy matrix during vacuum induction melting to provide 5, 10 and 20 vol.% (TiB+TiC) particulate reinforcement amounts. The wear behavior of the (TiB+TiC) particulate reinforced TMCs is described in detail with regard to the coefficient of friction, the hardness, and the degree of reinforcement fragmentation during sliding wear. The worn surfaces of each sliding wear condition are shown for the three types of wear studied here: transfer layer wear, particle cohesion wear and the development of abrasive areas. The fine reinforcements of TMCs were easily fragmented from the Ti matrix as compared to coarse reinforcements, and fragmented debris accelerated the decrease in the wear resistance.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1506-1508
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• 2010

$LiMnBO_3$ was successfully synthesized by a solid-state reaction method both with and without a carbon coating. Adipic acid was used as source material for the carbon coating. $LiMnBO_3$ was composed of many small polycrystalline particles with a size of about 50 - 70 nm, which showed a very even particle morphology and highly ordered crystalline particulates. Whereas the carbon coated $LiMnBO_3$ was well covered by mat-like, fine material consisting of amorphous carbon derived from the carbonization of adipic acid during the synthetic process. Carbon coated cell exhibited improved and stable discharge capacity profile over the untreated. Two cells delivered an initial discharge capacity of 111 and 58 mAh/g for $LiMnBO_3$/C and $LiMnBO_3$, respectively. Carbon coating on the surface of the $LiMnBO_3$ drastically improved discharge capacity due to the improved electric conductivity in the $LiMnBO_3$ material.