• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.1-8
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• 1997

The contamination structure and process on SUS 316 under various exposure conditions were investigated using x-ray photoelectron spectroscopy. The metal-oxide, metal-H-oxides, CO, COH, and $C_xH_y$ are the main components of contaminants on the SUS surface. The compositional profiles of the contaminants are shown to be $C_xH_y$/CO(COH)/metal-oxide on SUS. The contamination proceeds in two steps. The oxidation of the metallic constituents followed by adsorption of hydrocarbons. Under UHV conditions the contamination is mainly due to the oxidation, and, as the exposure time increases, the oxidation continues. In HV or higher pressure, most of the oxides are formed almost immediately after exposure and as the exposure time increases the contamination of hydrocarbons continues to grow. For the SUS sample exposed to atmosphere, the metal oxide is distributed deep inside the surface with an exponentially decreasing concentration, and its thickness is nearly in the order of photoelectron mean free path. It is also seen that the Fe oxide is segregated over Cr oxide in the highly oxidized samples.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.1
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• pp.27-34
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• 2013

Objectives: The purpose of this study is to calculate the worker-DNEL (Derived No Effect Level) values using the REACH guidance and compare the calculated DNELs with existing Korea occupational exposure limits (KOELs) for evaluation of the applicability of the worker-DNELs as provisional occupational exposure limits for chemicals that are not established KOELs in the workplace. Methods: The worker-DNELs for 46 chemicals among 113 hazardous substance requiring management were calculated using the REACH guidance, and a paired t-test was performed to see if there is any statistical difference between two lists (worker-DNELs vs KOELs). The ratios of KOELs over worker-DNELs were also calculated to compare the overall levels of two lists using the geometric means method. Results: The calculated worker-DNELs for 46 chemicals ranged from 0.001 to $329mg/m^3$ (GM= 6.9, GSD = 10.8), and appeared to be a significant difference between the worker-DNELs and the KOELs (p < 0.01). In addition, the ratios of KOELs over worker-DNELs ranged from 0.3 to 394 times (GM = 10.2, GSD = 3.9), indicating that the worker-DNELs were, on average, 27 times lower than the KOELs. Conclusions: Therefore, the study results show that the calculated worker-DNELs can be applied and used as provisional occupational exposure limits in the workplace in order to reduce worker exposures to chemicals and health risks, and manage potential worker exposures based on the precautionary principle through comprehensive chemical risk assessment.

• Journal of Radiation Industry
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• v.18 no.1
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• pp.23-33
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• 2024

This study was conducted to analyze the characteristics of three high-exposure tasks performed by radiation workers in Korean pressurized water reactors (PWRs) and to identify factors that reduce their exposure during work. Three high-exposure tasks were selected based on a previous study. In this previous study, nozzle dam installation and removal, eddy current testing, and manway opening and closing were determined as high-exposure tasks through normalization (radiation dose per unit time). Based on the analysis of the characteristics of the high-exposure tasks in this study, the high-exposure tasks were steam generator-related tasks performed inside and outside the water chamber. This study analyzed the reduction factors for high-exposure tasks and suggested improvements in terms of time, distance, and shielding. The use of the characteristics of high-exposure tasks and their dose reduction factors enables Korean PWRs to optimize radiation protection for workers who receive relatively high doses.

• Journal of radiological science and technology
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• v.19 no.2
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• pp.59-65
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• 1996

We studied exposure techniques and exposure dose for simple abdomen A-P projection for 41 medical facilities that are located in Seoul area. 1. The range of tube voltage used was 60 to 84 kVp, the average tube voltage used was 74 kVp 2. Only 17% of added filter was used. 3. Tube current mostly used was 200 mA, some of them used 400 mA. 4. The grid ratio mostly was used 10 : 1, 54 % of the rare earth screen was used in most facilities. 5. The average skin entrance dose was 4.15 mSv and the dose range was 1.05 mSv to 11.0 mSv.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.845-849
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• 2001

The new phto-alignment material PMI5CA, poly{N-(phenyl)maleimide-co-3-[4-(pentyloxy) cinamate]porpyl-2-hydroxy-1-methacrylate}, was synthesized and the electro-optical (EO)characteristics in the vertical-aligned(VA) liquid crystal display (LCD) photo-aligned on the photopolymer surface were studied. Excellent Voltage-transmittance(V-T) characteristics in the VA-LCD photoaligned with polarized UV exposure of oblique direction on the pohotopolymer surface for 1 min can be achieve. The transmittance of the VA-LCD photoaligned on the photopolymer surface decreased with increasing UV exposure time. We suggest that decrease of transmittance in the VA-LCD photoaligned on the photopolymer surface is attributed to the dissociation of the ester linkage in the photodimerized cinnamate structure with increasing UV exposure time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.269-273
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• 2014

The objective of this study is to safety assessment for human body on the guided missile combustion products. This study is to verify the safety assessment when operating the interior missile ejection take on verify the safety of the human body. During the missile ejection of combustion products, this study is analyzed combustion products. Result are accepted NIOSH and KOSHA of the safe guideline, and 6 exposure gas to the specified values 42% (CO), 22% ($CO_2$), not detected (others) are within minimal exposures criteria of the reference value respectively. Contribution of these results supported that interior missile ejection during combustion products may have been ensured human safely. Therefore, the future for improving the environmental safety of the shooting projectile steel plate round, dust collector, ventilation and other facilities is to improve environmental safety and efficient renovated design needed by target focused areas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.358-361
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• 2001

A new photoalignment material PM15CA, poly{N-(phenyl)maleimide-co-3-[4-(pentyloxy) cinnamate]propyl-2-hydroxy-1-methacrylate}, was synthesized and the electro-optical (EO) characteristics in the vertical-aligned (VA) liquid crystal display (LCD) photo-aligned on the photopolymer surface were studied. Excellent voltage-transmittance(V-T) characteristics in the VA-LCD photoaligned with polarized UV exposure of oblique direction on the pohotopolymer surfaces for 1 min can be achieved. The transmittance of the VA-LCD photoaligned on the photopolymer surface decreased with increasing UV exposure time. We suggest that the decrease of transmittance in the VA-LCD photoaligned on the photopolymer surface is attributed to the dissociation of the ester linkage in the photodimerized cinnamate structure with increasing UV exposure time

• BioChip Journal
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• v.12 no.4
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• pp.304-308
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• 2018

Atopic disease is caused by a complex combination of environmental factors and genetic factors, and studies on influence of exposure to various environmental factors on atopic diseases are continuously reported. However, the exact cause of atopic dermatitis is not yet known. Our study was conducted to analyse the association of SNPs with the development of atopic disease in a small cohort. Samples were collected from the Mothers' and Children's Environmental Health (MOCEH) study and 192 cord blood DNA samples were used to identify incidence of atopy due to influence of exposure to environmental factors. Genetic elements were analysed using a precision medicine research (PMR) array designed with various SNPs for personalized medicine. Case-control analysis of atopy disease revealed 253 significant variants (p<0.0001) and SNPs on five genes (CARD11, ZNF365, KIF3A, DMRTA1, and SFMBT1) were variants identified in previous atopic studies. These results are important to confirm the genetic mutation that may lead to the onset of foetal atopy due to maternal exposure to harmful environmental factors. Our results also suggest that a small-scale genome-wide association analysis is beneficial to confirm specific variants as direct factors in the development of atopy.

• Korean Journal of Veterinary Research
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• v.59 no.2
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• pp.101-104
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• 2019

This study examined the disinfection conditions (exposure time, 0-30 min; exposure temperature, $4^{\circ}C-65^{\circ}C$) of hypochlorous acid water (HOCl) in automobile disinfection equipment. The study tested poliovirus type 1 (PV1), low pathogenic avian influenza virus (AIV, H9N2), and foot and mouth disease virus (FMDV, O type). As a result, the PV1 and FMD viruses were inactivated easily (virus titer 4 log value) by HOCl (> 100 ppm) but the AIV required higher exposure temperatures (> $55^{\circ}C$). In conclusion, the exposure temperature and time are important factors in deactivating AIV and FMDV.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.1.1-2
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• 2002

Ultimate objective of industrial hygiene is the prevention of health impairment that may result from exposure to chemicals at workplaces. This implies the definition of permissible levels of exposure, that is, levels that according to the present status of knowledge are estimated to cause no adverse health effects during the lifetime of the workers, and the regular assessment of the possible health risk associated with exposure by comparing the current or the integrated exposure with the permissible exposure limits. Workers in solvent thinner-using occupation environment might be highly exposed to VOCs(volatile organic compounds) because solvent thinner has been used extensively such as painting, spraying, degreasing, coating and so on in Korea. The purpose of this study was to recognize, evaluate and propose the alternative control the VOCs from solvent thinner-using workplace.