• 한국화재소방학회논문지
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• 제27권2호
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• pp.70-74
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• 2013

화재 현장에서 수집된 화재증거물은 신뢰성 있는 용기에 수집, 보관 되어 감정기관으로 제공되어야 한다. 본 연구에서는 인화성 물질 5종(톨루엔, 노말옥탄, o-자일렌, 노말데칸, 노말헥사데칸)의 장판화재 증거물과 10 ${\mu}L$의 인화성 물질 5종을 적신 킴와이프스 종이를 4가지 용기(금속캔, 유리병, 나일론 지퍼백, 나일론 실링 백)에 두고, 온도 및 보관 기간에 따라 보관한 후 시료 속의 인화성 물질 잔존 유무를 가스크로마토그래프/질량분석기를 이용하여 확인하였는데, 그 결과 테프론이 코팅된 마개를 가진 유리병의 경우가 $60^{\circ}C$에서 22일 동안 보관하여도 5종의 화학물질이 검출이 가능하여, 유리병이 보관 성능이 가장 우수함을 확인하였다.

• 한국환경과학회지
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• 제21권11호
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• pp.1321-1331
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• 2012

To date, carbon and nitrogen co-doped photocatalysts (CN-$TiO_2$) for environmental application focused mainly on the aqueous phase to investigate the decomposition of water pollutants. Accordingly, the present study explored the photocatalytic performance of CN-$TiO_2$ photocatalysts for the purification of indoor-level gas-phase aromatic species under different operational conditions. The characteristics of prepared photocatalysts were investigated using X-ray diffraction, scanning emission microscope, diffuse reflectance UV-VIS-NIR analysis, and Fourier transform infrared (FTIR) analysis. In most cases, the decomposition efficiency for the target compounds exhibited a decreasing trend as input concentration (IC) increased. Specifically, the average decomposition efficiencies for benzene, toluene, ethyl benzene, and xylene (BTEX) over a 3-h process decreased from 29% to close to zero, 80 to 5%, 95 to 19%, and 99 to 32%, respectively, as the IC increased from 0.1 to 2.0 ppm. The decomposition efficiencies obtained from the CN-$TiO_2$ photocatalytic system were higher than those of the $TiO_2$ system. As relative humidity (RH) increased from 20 to 95%, the decomposition efficiencies for BTEX decreased from 39 to 5%, 97 to 59%, 100 to 87%, and 100 to 92%, respectively. In addition, as the stream flow rates (SFRs) decreased from 3.0 to 1.0 L $min^{-1}$, the average efficiencies for BTEX increased from 0 to 58%, 63 to 100%, 69 to 100%, and 68 to 100%, respectively. Taken together, these findings suggest that three (IC, RH, and SFR) should be considered for better BTEX decomposition efficiencies when applying CN-$TiO_2$ photocatalytic technology to purification of indoor air BTEX.

• 한국전기전자재료학회논문지
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• 제12권1호
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• pp.62-68
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• 1999

Ferroelectric $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$(x=0, 0.1, 0.2, 0.3) thin films were deposited on $Pt/SiO_2/Si$ substrate by MOD(Metalorganic Decomposition) process. Metal carboxylate and metal alkoxide were used as precursors, and 2-methoxyethanol, xylene as solvents. After spin coating, thin films were pre-annealed at $400^{\circ}C$, followed by RTA(Rapid Thermal Annealing) and final annealing at $800^{\circ}C$ in oxygen atmosphere. These procedures were repeated three times to obtain thin films with the thickness of $2000{\AA}$. To enhance the nucleation and growth of layered-perovskite phase, thin films were rapid-thermally annealed above $720^{\circ}C$ in oxygen atmosphere. As RTA temperature increased, fluorite phase was transformed to layered-perovskite phase. And the change of Nb contents affected dielectric / electrical properties and microstructure. The ferroelectric characteristics of $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$ thin film were Pr=8.67 $\mu{C}/cm^2$, Ec=62.4kV/cm and $I_{L}=1.4\times10^{-7}A/cm^2$ at the applied voltage of 5V, respectively.

• 보존과학연구
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• 통권21호
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• pp.77-99
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• 2000

Tumuli located in Chodang-dong in Kangreung City are sitesexcavated by the Museum of Kangreung University in 1993.Ofthese sites, a gilt bronze crown and gilt bronze sword with ring pommel with a tri-leaf ornament were excavated from the B-16tumulus. Underneath the gilt bronze crown was the gilt bronzes word with ring pommel with tri-leaf ornament, and these artifacts were treated with Polyurethane foams on the spot followed by special measures for conservation. This manuscript describes measures for conservation andanalysis with regard to the gilt bronze crown, gilt bronze sword with ring pommel with tri-leaf ornament and gilt bronze beltornaments. Bronze on the gilt bronze crown was completely corroded, therefore it was consolidated together with soil in the back of the artifact with Paraloid B72 after cleaning. Polyurethanefoams bottom was finished by applying the mixture of Epoxy resinAW106 and HV935K with soil. On the sword with ring pommel, the wooden part of the hilt was coated with Paraloid B72 (in Xylene) and the blade was consolidated with Paraloid NAD-10 30% after desalting with Sodium sesquicarbonate method. The gilt bronzebelt ornaments were treated with 3% Benzotriazole, coated with Paraloid B72 and then joined by using Cyanlacrylate. Specimens for the gilt bronze crown and gilt bronze belt ornaments were produced and gilding layers were examined under a metallographic microscope. The gilt bronze crown and the gilt bronze belt ornament maintained relatively good gilding quality with uniform gilding layers. Analysis of wood for the sheath of the sword with ring pommel revealed it to be Juglans mandshurica. Further more, analysis of constituents for a blue colored grassbead from dissolution of Polyurethane foams found it to be from the $Na_2O$-CaO-$AI_2O_3$-$SiO_2$ family.

• 보존과학회지
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• 제27권2호
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• pp.135-144
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• 2011

금속유물 보존처리시 유물 상태, 재질 및 환경 등 보존처리자의 판단에 따라서 다양한 코팅제를 사용하게 된다. 코팅제 종류 및 용제에 따라서 cyanoacrylate 접착제의 초기접착속도에 차이를 나타내므로 보존처리 효율성과 연관이 있다. 본 연구에서는 코팅제 종류와 용제에 따라 cyanoacrylate 접착제의 초기접착속도에 미치는 영향과 원인에 대해 알아보았다. 그 결과, 표면의 거칠기가 편평할수록 접착제의 젖음성이 향상되어 빠른 접착이 이루어졌다. 또한 V-Flon의 C-F, C-O-C 흡수 피크와 코팅제의 분자량과 유리전이온도는 초기접착속도에 영향을 미치는 요인으로 크게 작용하였다. 이와 같은 표면 화학적 분석 결과를 토대로 초기접착속도를 측정한 결과 접착제의 종류 및 점도에 따른 상대적 차이는 있으나 모든 접착제에서 V-Flon > Paraloid B-72(in xylene) > Paraloid NAD-10 > Paraloid B-72(in acetone)순으로 초기접착속도를 확인하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권1호
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• pp.1-6
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• 2015

The objectives of this study were to calculate the radius of influence (ROI) of well for an air-sparging (AS)/soil vapor extraction (SVE) system and to evaluate the applicability of the system applied for the remediation of the petroleum contaminated rail site. For air permeability test, three monitoring wells were installed at a location of 1.3 m, 2.3 m, 3.0 m from the extraction well. And the pressure of each monitoring well was measured by extracting air from the extraction well with the pressure and flow of $(-)2,600mmH_2O$ and $1.58m^3/min$. The ROI for an extraction well was calculated as 4.31 m. Air was injected into the injection well with the pressure and flow of $3,500mmH_2O$ and $0.6m^3/min$ to estimate the radius of influence for oxygen transfer. Oxygen concentrations of air from three monitoring wells were measured. The ROI of an injection well for oxygen transfer was calculated as 3.46 m. The 28 extraction wells and 19 injection wells were installed according to the ROI calculated. The AS/SVE system was operated eight hours a day for five months. The rail site was contaminated with the petroleum and concentrations of benzene, toluene, and xylene were over the 'Worrisome Standard' of the 'Soil Environment Conservation Act'. The contaminated area was estimated as $732m^2$ and contaminants were dispersed up to (-)3 m from the ground. During the operation period, soil samples were collected from 5 points and analyzed periodically. With the AS/SVE system operation, concentrations of benzene, toluene, and xylene were decreased from 7.5 mg/kg to 2.0 mg/kg, from 32.0 mg/kg to 23.0 mg/kg, from 35.5 mg/kg to 23.0 mg/kg, respectively. The combined AS/SVE system applied to the rail site contaminated with volatile organic compounds (VOCs) exhibited a high applicability. But the concentration of contaminants in soil were fluctuated due to the heterogeneous of soil condition. Also the effect of the remediation mechanisms was not clearly identified.

• 대한환경공학회지
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• 제28권7호
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• pp.757-763
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• 2006

본 연구에서는 BTEX로 오염된 저질로부터 순수 분리한 BTEX를 탄소원으로 $NO_3$-N를 전자수용체로 이용하는 미생물의 오염토양에 대한 현장 적용 가능성을 평가하였다. 이와 함께 주입한 순수 분리 미생물과 토착 미생물과의 상호 관계를 관찰하기 위하여 시간 경과에 따른 오염된 토양에서의 미생물 군집 변화도 관찰하였다. 이를 위해 BTEX로 오염 가능성이 적은 지역으로부터 채취한 토양 시료 100 g에 benzene, toluene, ethylbenzene, o-xylene을 각각 일정량 주입한 후, 동정 분리한 Pseudomonas stutzeri strain 15(DQ 202712):Klebsiella sp. strain 20(DQ 202715):Citrobacter sp. strain A(DQ 202713)를 2;1:1의 비율로 주입하여 BTEX 분해 효율과 미생물 군집 변화를 관찰하였다. 실험결과, $NO_3$-N와 BTEX가 모두 존재하는 조건에서 동정 분리한 미생물에 의한 분해 효율이 가장 높게 관찰되었다. 그리고 PCR-DGGE를 통한 미생물 군집 변화 관찰 결과, 토양 내 존재하는 다양한 미생물들의 peak는 대부분 감소된 반면, 주입한 동정분리 미생물 peak는 증가되는 것을 관찰할 수 있었다. 그러나 주입한 미생물 3종 가운데 Pseudomona stutzeri만이 우점화 된 결과가 관찰되었다.

• 한국산업보건학회지
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• 제6권2호
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• pp.313-321
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• 1996

Our laboratoy has been participated in Proficiency Analytical Testing (PAT) program which is operated by the Americal Industrial Hygiene Association in cooperation with the National Institute for Occupational Safety and Health (NIOSH). The program is designed to assist a laboratory improve its analytical performance by providing samples on a quarterly basis, evaluating the results, and providing reports on how well the laboratory performed. Evaluation of the results reported here covers five rounds of the PAT program (round 121~round 125). The way a laboratory is evaluated by PAT program is as follows: 1) There is no overall proficiency rating given to a laboratory. 2) A proficiency rating is given for each type of analyze (i.e., metals, silica, asbestos, solvents) that a laboratory analyzed. 3) Proficiency is rated acceptable ("A") if Z score lies between -3 and +3, and unacceptable if Z score is either higher than +3 ("H") or lower than -3 ("Lo"). Z score = (reported data - reference value) / standard deviation 4) For a laboratory to be rated proficient it must either have had no outliers over the most recent two rounds or of the samples actually analyzed over the past year (past four rounds), 75 % or more of the analyze sample results must be acceptable. According to the above rating criteria of PAT program, performance of metals including cadmium, lead, chromium and zinc, and asbestos sample analyses were rated acceptable ("A"). For silica analyses, all samples except one out of four samples in round 122 was rated high("H") were acceptable showing 95 % of ing 95 % of acceptance rate (19/20) throughout the rounds. Analyses of organic solvents were done on 52 samples in 9 types including methanol(MOH), 1,1,1-trichloroethane(MCM), tetrachloroethylene(PCE), trichloroethylene(TCE), benzene(BNZ), o-xylene(OXY), toluene(TOL), chloroform(CFM), 1,2-dichloroethane(DCE). All samples analyzed were rated acceptable except 2 samples that were rated high; one out of each four MCM and TCE samples in round 121, and one that was low out of four o-xylene analyses in round 122 indicating 94 % of acceptance rate(49/52) throughout the rounds. According to the laboratory rating criteria, our laboratory is rated proficient so far for all types of contaminants.

• 분석과학
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• 제20권6호
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• pp.453-459
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• 2007

신축공동주택의 실내공기질에 영향을 미치는 휘발성유기화합물 및 카보닐화합물의 농도와 입주 후 거주기간에 따른 오염도 변화추이를 파악하고자 입주 후 신축 공동주택 120세대를 대상으로 실내공기 오염도를 조사하였다. 신축 공동주택 입주 후 TVOC (Total Volatile Organic Compounds; TVOCs)평균농도는 $688.61{\mu}g/m^3$으로 나타났으며, 포름알데히드, 톨루엔, m, p-자일렌, 아세톤, 에틸벤젠이 $158.56{\mu}g/m^3$, $146.58{\mu}g/m^3$, $69.28{\mu}g/m^3$, $63.80{\mu}g/m^3$, $29.65{\mu}g/m^3$의 순으로 높게 나타났다. 또한, 대부분의 실내오염물질들은 입주 후 거주기간이 증가함에 따라 평균농도가 감소하는 경향을 나타내었으나, d-리모넨의 경우 입주 후 2개월에서 10개월까지 지속적으로 증가하는 것으로 나타났다. 또한, 톨루엔, 에틸벤젠, m, p, o-자일렌 등의 주요오염물질이 전체 VOCs에서 차지하는 비율은 38.8%로 나타났으며, 거주기간에 증가함에 따라 구성비율이 감소하는 것으로 나타났다.

• 분석과학
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• 제20권1호
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• pp.17-24
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• 2007

신축공동주택에서 발생되는 실내공기 오염물질 중 휘발성유기화합물 및 카보닐화합물의 농도분포특성을 파악하고자 신축공동주택 120세대를 대상으로 실내공기 오염도 실태조사를 실시한 결과, 입주 전 신축공동주택의 실내공기 오염물질 농도는 톨루엔이 $272.81{\mu}g/m^3$, m, p-자일렌 $98.90{\mu}g/m^3$, 포름알데히드 $71.68{\mu}g/m^3$, 아세톤 $70.58{\mu}g/m^3$, 에틸벤젠 $49.76{\mu}g/m^3$로 조사되었다. TVOCs 물 구성비의 경우, 표준물질로 확인된 물질이 42.5%를 차지하였으며, 이 중 톨루엔이 18.5%로 가장 많은 비중을 차지하였다. 카보닐화합물의 경우, 포름알데히드와 아세톤이 각각 43.1%, 42.4%를 차지하였다. 또한, 주요 실내공기 오염물질의 실내/실외 농도비를 조사한 결과 벤젠은 1.29로 낮은 농도비로 조사되었으며, 톨루엔은 3.59, 포름알데히드는 10.76, o-자일렌은 28.74의 실내/실외 농도비를 나타내었다.