• 한국물환경학회지
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• 제21권5호
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• pp.496-499
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• 2005

Power Plant is requested, by environmental bodies and fisherman, to correct the pollution of coastal area due to the outflow of foam from the outlet of the power plants. Foam wastewater cause a lot of environmental problems, expecially in aesthetic points of view. Therefore, It is needed to be collect from the stream into nearby ocean, and the collected foams should be treated before being discharged into nearby ocean. The most effective and feasible treatment method researched for the effective treatment of foam wastewater generated at the power plants. The result of the test is confirmed with collecting Foam wastewater by inhalation force. The treatment pilot ($3m^3/hr$) collected wastewater was operated by Biological degradation method(Aerobic/anaerobic Processes) for approximately two months. It was removed SS, COD, nutrient(T-P, T-N), etc. The System is expected successfully by Minimizing the operating costs such as electricity, repair expenses, chemicals and supplies expenses.

• 상하수도학회지
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• 제36권5호
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• pp.261-273
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• 2022

In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E2호
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• pp.57-68
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• 2006

Four intensive seasonal sampling campaigns between October 1998 and October 1999 were undertaken at an urban site of Chongju, in which polyurethane foam (PUF) sampler was used to collect particulate- and vapor-phase polycyclic aromatic hydrocarbons (PAHs). The contribution to total (particulate+vapor) PAH concentration by the vapor phase component exceeded the particulate phase contribution by factor of ${\sim}2.6$. Summed concentrations of phenanthrene (30.9%), pyrene (16.6%), naphthalene (11.3%) and fluoranthene (11.0%) account for significant amounts of the vapor-phase, while chrysene (12.5%), benzo[b]fluoranthene (11.6%), indeno[123-cd]pyrene (9.9%), benzo[ghi]perylene (9.5%), benzo[k]fluoranthene (9.4%), pyrene (8.9%), and benzo[a]pyrene (8.3%) are found to be the most common PAH compounds in the particulate phase. The results from application of principal component analysis to particulate-phase PAH data demonstrate that a combination of PAH and $PM_{2.5}$ inorganic data is a more powerful tracer of emission sources than PAH species data alone. Particulate-phase PAH species were found to be associated predominantly with emissions from diesel engine vehicles and incineration.

• Journal of Korean Society for Atmospheric Environment
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• 제19권E2호
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• pp.89-97
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• 2003

Ambient polycyclic aromatic hydrocarbons (PAHs) were measured during the winter and summer of 2002 in Chongju. A filter pack and polyurethane foam (PUF) system was employed to collect simultaneously the particulate and gas phase PAHs. The samples were then analyzed using a gas chromatograph equipped with mass spectrometer detectors (GC/MSD). A total of 29 samples were collected and 11 PAH species were identified. The lower molecular weight PAH compounds (3∼4 rings) dominated the total PAH mass. The higher molecular weight PAH compounds (5∼6 rings) were less abundant. The PAHs were showed to exhibit seasonal variations. The concentrations of all com-pounds were significantly higher in winter than summer. The lower molecular weight PAHs were mostly found in the gas phase whereas the heavier ones were mainly associated with particulate phase. Vehicle emissions are likely to be the primary contributor of PAHs in Chongju. This study also demonstrated that it is necessary to perform simultaneously particulate and gas phase measurements to determine the accurate concentrations of ambient PAHs.

• 한국과학교육학회지
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• 제7권2호
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• pp.21-35
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• 1987

Polyurethane foam was utilized to collect protists from the 2 ponds in Seoul National University and another pond in vicinity of Paldang Dam. The identified protists were 4 species in Cyanophyta, 2 species in Euglenophyta, 19 species in Chrysophyta, 9 species in Chlorophyta, 2 species in Ciliophora, and 3 species in Sarcodian. To test the adoptability of the sampling method for classes in junior and senior high school, frequency of the 25 protists in each observation and in each preparation were calculated. The families which were present at high frequencies were Naviculaceae. Fragilariaceae, Cymbellaceae and Coelastraceae. In an experimental application of the 40 pictures taken from the samples, students in junior classes recognized the protists by their outer morphology, internal structure. color, and colonial types, in decreasing order. Use of the collecting method and the applicability of protists for teaching biology were discussed.

• 분석과학
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• 제14권2호
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• pp.167-172
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• 2001

계면활성제를 이용하여 한지 섬유질 슬러지를 폐수시료로부터 효율적으로 제거하는 방법에 대해 연구하였다. 섬유질 슬러지의 농도가 약 80mg/L 인 실험 시료를 음이온 계면활성제인 sodium oleate를 이용하여 부상시켜 제거하려고 할 때 농도는 10mg/L, 유리필터 구멍크기는 $5-10{\mu}m$, 공기 유속은 200 mL/min이 적당하였다. Sodium oleate는 $Ca^{2+}$ 이온과 같은 다가 양이온에 의해 방해를 받을 수 있는데 $Ca^{2+}$ 이온의 농도가 100mg/L 이하일 경우에는 영향이 없었다. 양이온 계면활성제인 cetyltrimethylammonium bromide(CTAB)를 이용하였을 때는 sodium oleate보다 제거율이 좋지 않았으며, 거품도 비교적 많이 생겼다. 전통한지 제조과정에서 분산제로 사용되는 $PAMID^{(R)}$를 실험 재료에 1mg/L 가한 후 CTAB를 1mg/L 가하더라도 섬유질 슬러지들이 매우 잘 엉겼으며 부상시켰을 때 30초 이내에 95% 이상 제거되었으나 sodium oleate는 효과적이지 못하였다.

• 대한물리의학회지
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• 제9권4호
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• pp.455-463
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• 2014

PURPOSE: The purpose of this study was to compare the effects of Graston and self-myofascial release (SMR) techniques on knee joint flexibility, hamstring, and quadriceps strength. METHODS: Twenty subjects with hamstring shortness participated in this study. The subjects were assigned randomly to one of two groups: The Graston technique (GT) group received intervention using a Graston instrument for one minute, and the SMR group performed self-exercises using a foam roll for one minute. The range of motion (ROM) of the knee joint was measured by active knee extension test, and a handheld dynamometer was utilized to collect the hamstring and quadriceps muscle strength. This experiment was performed by two physical therapists. The significant level was set at ${\alpha}$=0.05. RESULTS: The results were as follows: 1) The ROM of the knee joint and quadriceps muscle strength were significantly increased in both groups. 2) Hamstring muscle strength was significantly reduced in both groups. 3) There were no significant differences between the GT group and SMR group for any variable. CONCLUSION: The results of this study suggest that SMR is an effective and easy technique for restoring proper muscle length and strength in subjects with hamstring shortness. We recommend that SMR technique be used for treat hamstring shortness in clinical setting and home-program.