• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2227-2232
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• 2011

The new metrology, Advanced Poly-silicon Ultra-Trace Profiling (APUTP), was developed for measuring bulk Cu and Ni in heavily boron-doped silicon wafers. A Ni recovery yield of 98.8% and a Cu recovery yield of 96.0% were achieved by optimizing the vapor phase etching and the wafer surface scanning conditions, following capture of Cu and Ni by the poly-silicon layer. A lower limit of detection (LOD) than previous techniques could be achieved using the mixture vapor etching method. This method can be used to indicate the amount of Cu and Ni resulting from bulk contamination in heavily boron-doped silicon wafers during wafer manufacturing. It was found that a higher degree of bulk Ni contamination arose during alkaline etching of heavily boron-doped silicon wafers compared with lightly boron-doped silicon wafers. In addition, it was proven that bulk Cu contamination was easily introduced in the heavily boron-doped silicon wafer by polishing the wafer with a slurry containing Cu in the presence of amine additives.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.204-209
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• 2007

Agricultural area in the vicinity of the ${\triangle}{\triangle}$ smelting factory in Kyeongbuk province, the third largest zinc smelting factory in the world, was contaminated by high concentration of heavy metals. However, the heavy metals source was not yet directly traced and thus, resulted to a conflict between the factory and residents within its vicinity. In order to determine the level of heavy metal contamination in the arable lands located at the north eastern part of the factory, soils were sampled systematically. To find out the major reason for the occurrence of this problem, waters and aerosols were sampled with constant intervals to the upward and downward direction from the factory and were analyzed to find out the heavy metal concentrations. Cadmium (Cd) and zinc (Zn) of the heavy metals were highly accumulated more than the Korean warning criteria (Cd 1.5, Zn 300 mg $kg^{-1}$) with mean values 1.7 and 407 mg $kg^{-1}$, respectively, at the surface soils (0-20 cm), and heavy metal concentration significantly decreased with increasing soil depth In addition, the concentration of both metals slightly decreased with increasing distance from the factory to the surface soils. Cadmium and Zn were detected in the upward stream water with low concentration and concentrations increased significantly in the downstream after passing across the factory. Aerosol samples also showed traces of Cd and Zn which could be attributed to the contamination of the water system and the surface soils. Conclusively, Cd and Zn emitted from the ${\triangle}{\triangle}$ smelting factory moved with the aerosol in the atmosphere and thus, contaminated the agricultural areas and the water system within it vicinity.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.96-102
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• 2001

Bacteriological quality of beef carcass and distributions of pathogens in beef processing environments were investigated to improve the hygienic quality of fresh beef. Total bacterial contamination of carcass surface in slaughtering process and cutting board in cut-meat process showed 10$^{5}$ -10$^{6}$ CFU/$\textrm{cm}^2$ and 10$^{5}$ CFU/$\textrm{cm}^2$ in summer, respectively. The viable bacterial count of cotton glove was similar to that of cutting board during and entire period of year. Microbial contamination of carcass surface, cutting board, cotton glove and deboned meat showed the highest in summer and the lowest in winter during the year. Escherichia coli O157, Pseudomonas aeruginosa, Klebsiella. ornithinolytica, Staphylococcus aureus, E coli, Tatumella. ptyseos, Serratia odorifera, Aero-monas sobria, Enterobacter cloacae and Flavimonas oryzihabitans were isolated from carcass surface during slaughter treatments. S. aureus, Listeria grayi and L. monocytogenes were isolated from cutting board and L. grayi, Erwinia spp. Salmonella app. and S. aureus were isolated from cotton glove in cut-meat process environments. Citrobacter freundii; L. monocytogenes; and S. aureus were isolated from deboned meat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.772-784
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• 2011

We measured grain size, organic matter, and metallic elements (Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) in intertidal sediments collected from six islands in the western part of Jellanam Province in order to evaluate heavy metal contamination in the tidal flat sediments of coastal islands. The evaluation of metal contamination was carried out using geochemical assessment techniques such as sediment quality guidelines (SQGs), enrichment factor (EF), and geoaccumulation index ($I_{geo}$). Surface sediments were classified into four sedimentary facies: sand, gravelly muddy sand, slightly gravelly mud, and silt. The concentrations of heavy metals in intertidal sediments from Jaeun, Amtae, Biguem, and Docho islands showed good positive correlations with mean grain size and ignition loss, indicating that the concentrations of metallic elements in these sediments were dependent on grain size and the organic matter content. The concentrations of heavy metals in sediments from almost all of the stations were lower than two criterion values proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Based on the EF and $I_{geo}$ results, surface sediments were a little polluted for Cr and were moderately polluted for As. Our results suggest that more intensive studies are necessary in the future in order to determine the major source of As in intertidal sediment and to evaluate the As pollution level in macrobenthos.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.930-940
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• 2013

We evaluated contamination with organic matter and trace metals by analyzing grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Ni, Cr, Mn, Hg, and As) in surface sediments at 28 stations around the Geum River estuary in July 2008. The surface sediments in the estuary were mainly composed of coarse sediment (sand and muddy sand), with mean grain size (Mz) ranging between $2-4{\O}$. The high concentrations of IL, COD, and trace metals were mainly found at stations in front of the Gusan outer port and industrial complex, and near the Seocheon coast with relatively fine sediments. In addition, the concentrations of IL and all trace metals, except Pb and As, showed good positive correlations with Mz, indicating that the concentrations of organic matter and trace metals were mainly dependent on sediment grain size. The concentrations of COD, AVS, and trace metals in most sediments did not exceed the sediment quality guideline (SQGs). Although the sediments in the study region are not polluted with organic matter and trace metals, there are many point sources of pollutants, such as Gusan port and industrial complex, Janghang refinery, and a thermoelectric power plant around the Geum River estuary. Thus, the management of coastal environments through periodic monitoring of organic matter and trace metals is required in the future.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.1
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• pp.55-60
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• 2020

The aim of this study was to investigate the change of microbial contamination levels in the different areas and at the different time points after application of a quaternary ammonium compound (QAC) that has mechanical antimicrobial effect. The microbial contamination levels were measured in three different areas; unit chair handle, spit sink area and hand piece holder at different time points using adenosine triphosphate (ATP) monitoring system and ATP surface test kit. Hand piece holder showed the highest level of microbial contamination. In most of the clinics, QAC significantly reduced the levels of microbial contamination, and maintained antimicrobial activity for 4 to 6 months. QAC may be used effectively in dental clinics due to the duration of antimicrobial effect and the minimal exposure of chemicals and further studies are needed with large sample size.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.106-112
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• 2011

This study developed preliminary assessment methodology for priority listing of soil and groundwater contamination sources, considering source characteristics, local environments and risk receptors. Source characteristics were evaluated by scoring relative risk of contamination sources. Local environments were evaluated by scoring annual rainfall, hydraulic conductivity of aquifer, and annual groundwater use. Risk receptors were evaluated by scoring local population, direct distance to surface water, direct distance to drinking-water wells. Scores of each parameter were allocated by analysing distribution of parameter values obtained from government databases. Distributed scores of source characteristics local environments: risk receptors were 12 : 12 : 12. The preliminary assessment scored 0 to 36 for each soil and groundwater sources. Inventory of soil and groundwater sources consisted of 7 categories. This study applied the preliminary assessment methodology to Manan-Gu, Anyang City, Korea. The number of car repair and washing facility was the largest in the contamination source inventory. Petroleum storage facilities showed the highest assessment score. The preliminary assessment methodology also indicated that Anyang-Dong was the priority section among Anyang-Dong, Suksu-Dong, Bakdal-Dong. This study is the first trial for relative ranking soil and groundwater contamination sources by considering source and local characteristics. Therefore, further researches and revision of the preliminary assessment methodology need to be pursued for various applications.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.38-43
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• 2012

Purpose: Patients injected with FDG use the bathroom that Measured surface contamination level and spatial dose rate. This study about the effect that result affects workers in same part. Materials and Methods: Group1 is St. Vincent' s hospital's 60case. Group 2 is Bucheon St. Mary's hospital's 50case. Last case is lower the average daily number of patients than group 2. Measured time is 8:00, 10:00, 13:00, 15:00 and 17:00. Measured part is 4 point of toilet, basin and wastepaper basket, also measured accumulation dose of toilet during 3 month. Hospitals is installed PET/CT ware surveyed on presence of bathroom that used only by patient and worker has been using the bathroom. Results: The highest average surface contamination level of toilet is group1($8.38{\pm}4.56$), but the highest spatial dose rate is group3. Cumulative exposure dose measured by TLD during 3months is St.Vincent's hospital 0.78 mSv and Bucheon St.Mary's hospital 0.37 mSv. And result of survey is 16.12% worker using the bathroom. Conclusions: The more daily number of patient, the higher surface contamination level of bathroom. Especially, wastepaper basket's surface contamination level is exceed the reference value $4Bq/cm^2$. Based on This survey, Bathroom require special attention and proper decontamination.

• Journal of the Korean Society of Visualization
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• v.3 no.1
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• pp.51-57
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• 2005

Vertices terminating at free surface have been investigated extensively. Most of investigations, however, are focused on surface parallel vortices and little has been known about surface normal vortex or columnar vortex. Visualized experimental results utilizing LIF technique are discussed fur the purpose of characterization of columnar vortex interacting with a clean and a contaminated free surfaces and a solid body interface in the present investigation. The results reveal that surface tension changes due to surface contamination although bulk viscosity remains constant and eventually the behavior of a columnar vortex interacting with a contaminated free surface and a solid body interface are totally different from the clean free surface case.

• Journal of Conservation Science
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• v.19
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• pp.5-18
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• 2006

The Mireuksaji stone pagoda of the Iksan was built in Muwang King of Baekjae Kingdom and has maintained its present status through several rebuilding process. Recently, the structural unbalance of the pagoda has worsened, so for scientific maintenance recovery of its original pagoda form, the pagoda is under dismantling process. The original form of this pagoda is being presumed to be a plane square pagoda of nine stories, though only a portion of six stories remains until today. The destroyed part from collapse was liked in insecure pagoda form by Japanese in year of 1915. On the surface of the stone which has gone through the present time, efflorescence appeared as precipitation substance over crusted and due to this phenomenon, the structure and color of thee original stone haven't been preserved. Therefore, quantitative analysis on its kind, emitted status and contamination type of secondary inorganic contamination substance of the over crusted surface were analyzed. Also through reaction experiments, contamination type was defined and tests have been applied to find the requirements that will wash out the contaminants. The result of this study will provide the base of quantitative analysis on the kind of inorganic contamination of the surface of stone assets, and it shall also contribute to the application of scientific maintenance recovery of surface cleaner for efflorescence.