• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.859-864
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• 2004

The solid solutions of the $Sr_{1-x}Ba_xFeO_{3-y)$ system (x = 0.0, 0.1, 0.2 and 0.3) having a perovskite structure were prepared in air at 1423 K and then heat-treated in air (A), $O_2(O)\;and\;N_2(N)$ to examine possibility of controlling the nonstoichiometry and applicability as an additive for electrical conducting inorganic adhesives (ECIA). In the samples heated in $N_2$ stream, there existed almost no $Fe^{4+}$ ions, and at constant temperature their electrical conductivities were considerably lower than those of the samples heat-treated in air or $O_2.\; Sr_{0.8}Ba_{0.2}Fe^{3+}_{0.49}Fe^{4+}_{0.51}O_{2.76}$ (SB2-A) whose $Fe^{3+}/Fe^{4+}$ ratio was nearly 1 (0.96) and whose conductivity values (1.04 $ohm^{-1}cm^{-1}$ at 283 K and 1.88 $ohm^{-1}cm^{-1}$ at 673 K) were higher than any other samples, was found to be the best additive for ECIA.

• 한국산업보건학회지
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• 제21권2호
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• pp.99-102
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• 2011

Objectives: Acetone/triacetine method for clearing cellulose ester membrane (CEM) filter has been a popular method for air-borne asbestos analysis. However, as a weakness of this method, it is time consuming to analyses asbestos samples after sampling. Crystalclear method can be used to analyses asbestos samples promptly after sampling. Although a strength of crystal clear method exists, there was little valid studied for the method. This study was conducted to compare acetone/triacetine method with crystalclear one for analysing asbestos sample. Methods: Test samples made in three different concentration ranges(low, medium and high concentration) were analysed by phase contrast microscopy after acetone/triacetine and crystalclear method treatment respectively. Results: We did not find statistical difference in analysed results between two methods, which were conducted in three different concentrations ranges. Conclusions: We concluded that crystalclear method can be used as clearing method for air-borne asbestos analysis instead of acetone/triacetine method.

• 한국산업보건학회지
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• 제22권2호
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• pp.91-99
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• 2012

Airborne chlorpyrifos concentrations in formulation workplaces have not been determined in Korea. The aim of the study was to evaluate chlorpyrifos concentrations of air in a formulation workplace and recognize the RBC cholinesterase activities for the formulation workers. 30 air samples (personal or area sampling) were collected and bood samples from 10 workers were collected for RBC chlorinesterase (RBC AChE) activity in a factory on May 2008. Air samples were collected by the National Institute for Occupational Safety and Health (NIOSH) method and were analyzed by GC-MS. Airborne chlorpyrifos concentrations ranged from 0.003 to $12.90mg/m^3$ and geometric mean (GM) was $0.15\;mg/m^3.$ Compared to Korean Occupational Exposure Limit (KOEL) of 0.1 (2011) or $0.2\;mg/m^3$ (2008), at 95% confidence, airborne concentrations exceeded the KOEL 69.7% or 56.1% of the time or less, indicating that this concentration level was unacceptable according to exposure assessment using a LogNorm2$^{(R)}$. Since the workers were continually at work on the organophosphate or carbamate pesticides formulation, individual baseline for RBC AChE activity was not determined. As the results of comparison with reference average value of RBC AChE activity, it was found that a worker was below 70% RBC AChE activity and five workers were abnormal.

• Corrosion Science and Technology
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• 제22권2호
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• pp.115-122
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• 2023

This study aimed to elucidate causes of corrosion of heat transport pipes and air vents installed under a manhole of heat transport facilities and suggest effective anticorrosive measures by applying paints or adhesive tapes. It was found that air vent corrosion was attributed to corrosion under insulation caused by the inflow of water and the enrichment of chloride ions. The infiltrated water caused a hydrolysis of polyurethane foam (PUF) insulation by concentrating chloride ions at the interface between a pipe and the PUF. As insulator deteriorated, more chloride ions were eluted as confirmed by ion chromatograph (IC) analysis. As an effective method to prevent air vent corrosion, different types of paints and adhesive tapes with higher corrosion resistance on chloride ions were applied and environmental resistance tests were performed with those samples. Based on environmental test results of samples exposed to 10% HCl solution, it was revealed that a wax tape was the most adequate from a viewpoint of stability at operating condition, environmental resistance, surface treatment, and field applicability.

• 한국대기환경학회지
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• 제5권1호
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• pp.68-78
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• 1989

The heavy metal of suspended particulates with human health has long been studied in environmental interest concerned. This study was intended to identify harmful heavy metals of the ambient air borne dusts which were related with the respirable sizes in the aerodynamics. Two sampling sites were selected comparatively; one was in the Shinchon area, which is the commercial district with heavy traffic and the other site was in the Bulgwang area which is residential area. The supended particulates were sampled by high volume air sample with 6 cascade impactor stages. The heavy metals in terms of As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn were determined by stomic absorption spectrometry or inductively coupled plasma emission spectrometry. The samples weretaken bimothly for seven consecutive days from May 1987 to March 1988. The annual average concentration of the respirable suspended dust of which diameter is less than 10$\mum$ was 152.59 $\mug/m^3$ of the Shinchon air samples; the respirable dust was equivalent to approximately 85% of the total suspended particulates. The annual average concentration of the respirable suspended dust of the Bulgwang air samples was 112.56 $\mug/m^3$; that was approximately 86% of the total suspended particulates. The concentration of heavy metals was investigated in relation to the particle size. The concentration of Cr, Fe, Mn and V were tended to be much more in the coarse particles than in the fine particles. Cd and Pb in the fine particles were more than in the coarse particles. In the partial correlation coefficients; in the Shinchon area, high correlations among Fe, Se and Mn were determined; it is assumed that those sources would be originated from coal, gasolineand diesel. In Bulgwang area, would be high correlation among Fe, Se, Hg and Mn considered to be originated from coal, Bunker-C and heavy oil as well. From the above results, the hazardous heavy merals in air should be measured and controlled in originally their sources.

• 환경위생공학
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• 제22권1호
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• pp.57-66
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• 2007

Changes in the alliinase activity during the hot air drying and vacuum freeze drying of garlic samples treated as the whole, sliced and crushed state were investigated. The specific activity of alliinase in raw garlic was 8.52 units/mg protein. The activity in the whole garlic prepared by the hot air drying for 8 hrs was reduced remarkably to 5.22 units/mg protein with 61% remaining and to 4.25 units/mg protein with 50% remaining for 36 hrs. The activity in the sliced garlic prepared by the hot air drying for 36 hrs was reduced to 3.55 units/mg protein with 42% remaining and the activity in the crushed garlic prepared by the hot air drying for 36 hrs was reduced to 3.12 units/mg protein with 37% remaining. The garlic sample sliced or crushed was higher than the whole state in the efficiency of drying but was lower in the remaining activity of alliinase. The activity in the whole garlic prepared by the vacuum freeze drying for 8 hrs was reduced to 7.21 units/mg protein with 85% remaining and to 5.53 units/mg protein with 65% remaining for 36 hrs. The activity in the sliced garlic prepared by the vacuum freeze drying for 36 hrs was reduced to 4.55 units/mg protein with 53% remaining and the activity in the crushed garlic prepared by the vacuum freeze drying for 36 hrs was reduced to 4.16 units/mg protein with 49% remaining. The remaining activity of alliinase in the garlic samples prepared by the vacuum freeze drying was higher than the remaining activity in the garlic samples prepared by the hot air drying.

• 한국대기환경학회지
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• 제14권5호
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• pp.507-518
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• 1998

A field comparison study was carried out to quantify differences among various sampling and analytical methods for volatile organic compounds (VOCs) at a site in Vlsan in June 1997. Air sampling containers (SUMMA canisters) were used by the Korea Institute of Science and Technology (KIST) and adsorption tubes (carbotrap) were used by Yeungnam University (YN Univ.) for sampling ambient air. Duplicate samples obtained by KIST were analyzed by KIST with a GC-MS system for aromatics and halogenated hydrocarbons and by Atm AA with a GC -FID system for C2∼C9 hydrocarbons, respectively. The adsorption tube samples were analyzed by YN Univ. with a GC-FID system for aromatics. VOC levels for the duplicate canister sampls analyzed by KIST and Atm AA were in good agreement. Concentrations of aromatics by the adsroption tube method were generally higher than those by the canister sampling method by factor of 1.5 to 2.0. Differences between the two sampling methods were discussed.

• 한국의류학회지
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• 제11권1호
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• pp.21-28
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• 1987

Since the air permeabilities are closely connected with clothing hygiene, air permeabilities required to optimize dressing were studied and measured the air permeabilities that take air layers among fabrics into account. The thickness of air layers were controlled from 3mm to 24mm, and the numbers of air layers were made from one layer to three layers. The samples used were selected in casual wears in spring and autumn. The results obtained are as follows; 1. Specific air permeabilities of superimposed fabrics decreased gradually according to the increase of superimposed number. 2. Specific air permeabilities of the same kind of fabrics increased at first and later decreased by the increase of intervals when the fabrics are superimposed at regular intervals, and those of the different kind of fabrics decreased. 3. Specific air permeabilities of the different kind of fabrics decreased to the 18mm of total thickness in air layers and increased later.

• Safety and Health at Work
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• 제14권2호
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• pp.237-242
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• 2023

Background: This study evaluated occupational exposure levels of doxorubicin in healthcare workers performing rotational intraperitoneal pressurized aerosol chemotherapy (PIPAC) procedures. Methods: All samples were collected during PIPAC procedures applying doxorubicin to an experimental animal model (pigs). All procedures were applied to seven pigs, each for approximately 44 min. Surface samples (n = 51) were obtained from substances contaminating the PIPAC devices, surrounding objects, and protective equipment. Airborne samples were also collected around the operating table (n = 39). All samples were analyzed using ultra-high performance liquid chromatography-mass spectrometry. Results: Among the surface samples, doxorubicin was detected in only five samples (9.8%) that were directly exposed to antineoplastic drug aerosols in the abdominal cavity originating from PIPAC devices. The telescopes showed concentrations of 0.48-5.44 ng/cm² and the trocar showed 0.98 ng/cm² in the region where the spraying nozzles were inserted. The syringe line connector showed a maximum concentration of 181.07 ng/cm², following a leakage. Contamination was not detected on the surgeons' gloves or shoes. Objects surrounding the operating table, including tables, operating lights, entrance doors, and trocar holders, were found to be uncontaminated. All air samples collected at locations where healthcare workers performed procedures were found to be uncontaminated. Conclusions: Most air and surface samples were uncontaminated or showed very low doxorubicin concentrations during PIPAC procedures. However, there remains a potential for leakage, in which case dermal exposure may occur. Safety protocols related to leakage accidents, selection of appropriate protective equipment, and the use of disposable devices are necessary to prevent occupational exposure.

• 한국수산과학회지
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• 제14권1호
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• pp.7-14
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• 1981

꽁치($2^{\circ}C$와 $10^{\circ}C$) 및 삼치육($2^{\circ}C$와 $15^{\circ}C$)은 저장하였을 때의 육중의 TMAO-N, TMA-N 및 TMA-N의 경시적인 변화와 아울러 이들 어육을 저장, 열풍건조 및 일건하였을 때의 변화에 대하여 실험하여 다음과 같은 결과를 얻었다. 1. TMAO의 변화에 있어서 5일간 저장하였을 때 $2^{\circ}C$의 경우, 꽁치 몇 삼치육은 각각 생시료때의 $48\%$ 및 $41\%$의 잔존율을 나타내었고 $10^{\circ}C$의 꽁치육과 $15^{\circ}C$의 삼치육의 경우는 각각 $39\%$ 및 $18\%$였다. 2. TMA의 변화는 5일간의 저장에서, $2^{\circ}C$의 경우 꽁치 및 삼치육은 각각 생시료때의 6.5배양 및18배양의 증가를 보었고, $10^{\circ}C$의 꽁치와 $15^{\circ}C$의 삼치육의 경우는 각각 28.8배양 및 77.7배양이었다. 3. DMA의 변화는 5일간의 저장에서, $2^{\circ}C$의 경우 꽁치 및 삼치육은 각각 생시료때의 2.5배양 및 5.4배양의 증가를 나타냈고, $10^{\circ}C$의 꽁치와 $15^{\circ}C$의 삼치육의 경우는 각각 4배양 및 8배양이었다. 4. 제품별 TMAO의 함양은 꽁치의 경우, 염장품 > 열풍건조품 > 일건품의 순이었고 삼치의 경우는 염장품 > 일건품열풍건조품의 순이 있다. 5. 제품별 TMA의 합양은 꽁치의 경우, 열풍건조품 > 일건품 > 염장품의 순이였고 삼치의 경우는 일건품 > 열풍건조품 > 염장품의 순이었다. 6. 제품별 DMA의 함양은 모든 시료가 열풍건조품 > 일건품 > 염장품의 순이었다. 본 연구의 실험을 도와 준 성혜경 선생에게 감사를 드리는 바이다.