• 공업화학
• /
• 제28권2호
• /
• pp.257-262
• /
• 2017

본 연구에서는 electrospinning method의 공정변수를 다르게 하여 CNF (carbon nanofiber)를 제조하였다. 제조된 CNF의 섬유의 형태, 직경 등의 변화를 SEM 분석을 통해 관찰하였으며 인가전압, TCD (tip to collecor distance), 고분자 용액의 농도, 열처리 단계가 CNF 물성을 형성함에 있어 주요한 영향인자임을 확인하였다. 또한 서로 다른 물성으로 제조된 CNF를 전기분해 공정의 전극으로 적용하여 toluene의 제거 효율을 비교하였고, 이를 통해 anode 뿐만 아니라 cathode 역시 전기분해 효율에 직접적인 영향을 미침을 확인하였다.

• 한국대기환경학회지
• /
• 제28권1호
• /
• pp.12-21
• /
• 2012

The purpose of this study is to understand distribution of ozone concentration in the south coastal region of Korea by evaluating ozone spatial distribution in the upper air using aircraft. Sampling was carried out from May to August in 2009. The average concentration of ozone in the upper air was ranged from 32.3~90.8 ppb with its maximum concentration of 132 ppb. When it comes to the spatial distribution of ozone, ambient concentration was high in the air, 1,000 m and 500 m above the southern sea near the Gwangyang Bay area and emission sources, respectively. Daily mean concentration of NOy was 6.7~24.2 ppb and that of CO was 0.152~0.487 ppm. In addition, the concentration was appeared to be relatively high in the upper air of industrial regions and the southern seas. Meanwhile, the concentration of both $NO_y$ and CO was high in the upper air of the emission sources regardless of latitude. As for PAN, its daily mean concentration ranged between 0.1 and 0.6 ppb with overall mean concentration of 0.2 ppb. The average concentration of VOCs was 48 ppb, and the concentration of toluene and m,p-Xylene were higher than other components.

• Environmental Analysis Health and Toxicology
• /
• 제10권1_2호
• /
• pp.37-46
• /
• 1995

The purpose of this research is to estimate a safe environmental level of human exposure to thresholding-acting toxicants in drinking water and recommend the acceptable levels and management plans for maintaining good quality of drinking water' and protecting health hazard. This research has been funded as a national project for three years from 1992 to 1995. This study(the second year, 1993-1994) was conducted to monitor 39 species of noncarcinogenic chemicals such as volatile organic compounds(VOCs), polynuclear aromatic hydrocarbens(PAHs), pesticides and heavy metals of drinking water at some area in six cities of Korea, and evaluate health risk due to these chemicals through four main steps (hazard identification, exposure assessment, dose-response assessment and risk characterization) of risk assessment in drinking water. In hazard identification, 39 species of non-carcinogenic chemicals were identified by the US EPA classification system. In the step of exposure assessment, sampling of tap water from the public water supply system had been conducted from 1993 to 1994, and 39 chemicals were analyzed. Inclose-response assessment for non-carcinogens, reference doses(RfD) and lifetime health advisories(HAs) of lifetime acceptable levels were calculated. In risk characterization of detected chemicals, the hazard quotients of noncarcinogens were less than one except those of manganese and iron in D city.

• 분석과학
• /
• 제25권1호
• /
• pp.60-68
• /
• 2012

지표수 중에 GC-MS에 의한 25개 준휘발성유기물질을 동시에 분석하는 방법을 개발하였다. 1.0 L의 물 시료를 분액깔대기 안에 넣고 NaCl로 포화시킨 다음 40 mL methylene chloride로 두 번 추출하였다. 이 방법은 0.01-800 ng/L 범위의 직선성을 보였고 15% 이내의 정밀도를 보였다. 확립한 방법을 사용하여 금강물 16개 시료를 분석한 결과 준휘발성유기화합물이 0.02-96.8 ng/L의 농도범위로 검출되었으며 측정값은 US EPA 또는 독일에서 확립한 준거치 이하의 값을 보였다. 이 측정방법은 지표수에서 SVOCs 대한 국가모니터링사업에 사용할 때 효율적인 것으로 판단된다.

• 한국대기환경학회지
• /
• 제26권4호
• /
• pp.357-366
• /
• 2010

The purpose of this study is to evaluate a method for the measurement of N,N-Dimethylformamide (DMF) and to apply the method to the ambient air samples. For the determination of DMF together with other general VOCs (e.g., benzene, toluene, and xylenes), adsorption sampling and thermal desorption with GC/MS was used in this study. The sampling and analytical approaches tested in this study showed a good repeatability and linearity with lower detection limits of less than 0.35 ppb. Field measurements were carried out at three industrial sites (Daegu-Seongseo, Siwha and Banwall industrial complexes) and one residential site in Daegu city during a period from October 2006 to November 2008. DMF was detected in 71.8% of the total samples from the Seongseo industrial complex, well known for textile industry. In contrast, DMF was detected in only 20.4% and 12.9% of all the samples from the other two sites in Banwall and Siwha industrial complexes, respectively. This implies that sources of DMF should be strongly associated with textile industry. The mean concentration of DMF also appeared to be the highest in Seongseo site (5.95 ppb), followed by a residential site in Daegu (3.28 ppb), Banwall (0.88 ppb) and Siwha (0.55 ppb). In this study, we demonstrated the environmental significance of DMF in urban ambient air. To our knowledge, the DMF measurement introduced in this paper is the first case of an official report in Korea.

• 센서학회지
• /
• 제10권6호
• /
• pp.310-316
• /
• 2001

다양한 냄새를 인식하고 분석하기 위하여 metal oxide 형 센서어레이를 이용한 인공 냄새인식 시스템(전자 코 시스템)을 설계 제작하였다. 센서어레이로부터 측정되는 다차원 데이터를 관측자로 하여금 쉽게 구별 할 수 있도록 Euclidean distance를 기본으로 하는 unsupervised clustering 방법을 제안한다. 제안된 방법은 주성분 분석법을 Sammon의 매핑법을 시작점으로 사용한 결합방법으로 특정냄새가 속해있는 cluster들에 대한 가정이 필요하지 않으며, 주성분 분석법에서 나타나는 차원축소로 인한 오차를 최소화하고 Sammon의 매핑법 사용으로 나타나는 데이터베이스의 입력순서에 따른 cluster들의 회전현상을 제거할 수 있다. 제안된 unsupervised clustering 방법으로 구현된 인공 냄새인식 시스템은 휘발성 유기화합물과 국산양주들의 냄새 차이를 각각 평가하는데 사용되어졌고 실험을 통하여 좋은 성능을 검증하였다.

• Journal of Ginseng Research
• /
• 제40권4호
• /
• pp.453-461
• /
• 2016

Background: This study aims to describe the characterization of Paenibacillus polymyxa GBR-1 (GBR-1) with respect to its positive and negative effects on plants. Methods: The morphological characteristics of GBR-1 were identified with microscopy, and subjected to Biolog analysis for identification. Bacterial population and media optimization were determined by a growth curve. The potential for GBR-1 as a growth promoting agent, to have antagonistic activity, and to have hydrolytic activity at different temperatures was assessed. The coinoculation of GBR-1 with other microorganisms and its pathogenicity on various stored plants, including ginseng, were assessed. Results: Colony morphology, endospore-bearing cells, and cell division of GBR-1 were identified by microscopy; identification was performed by utilizing the Biolog system, gas chromatography of fatty acid methyl esters (GC-FAME). GBR-1 showed the strongest antagonistic activity against fungal and bacterial pathogens. GBR-1 cell numbers were relatively higher when the cells were cultured in brain heart infusion (BHI) medium when compared with other media. Furthermore, the starch-hydrolytic activity was influenced by GBR-1 at higher temperature compared to low temperatures. GBR-1 was pathogenic to some of the storage plants. Coinoculation of GBR-1 with other pathogens causes differences in rotting on ginseng roots. A significant growth promotion was observed in tobacco seedlings treated with GBR-1 suspensions under in vitro conditions, suggesting that its volatile organic compounds (VOCs) might play a role in growth promotion. Conclusion: The results of this study indicate that GBR-1 has both positive and negative effects on ginseng root and other stored plants as a potential biocontrol agent and eliciting in vitro growth promotion.

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2017년도 추계학술발표회
• /
• pp.236-236
• /
• 2017

Effluent treated by an NaDCC injection method in Ballast water management system (BWMS) contains reactive chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on marine environment. WET testing was carried out for four marine pelagic and freshwater organisms, i.e., diatom Skeletonema costatum, Navicula pellicuosa, chlorophyta Dunaliella tertiolecta, Pseudokirchneriella subcapitata, rotifer Brachionus plicatilis, Brachionus calyciflorus and fish Cyprinodon variegatus, Pimephales promelas. The biological toxicity test revealed that algae was the only biota that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50% (EC50) values of 25-50%, 50-100% and >100%, respectively, at three water condition, but did not show any significant toxicities on other biota. Meanwhile, chemical analysis revealed that the BWMS effluent contained total residual oxidants (TROs) below $0.03{\mu}g/L$ and a total of 25 DBPs such as bromate, volatile halogenated organic compounds (VOCs), halogenated acetonitriles (HANs), halogenated acetic acids (HAAs), chloropicrin and Isocyanuric acid. Based on ERA, the 25 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. The ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the other DBPs did not exceed 1 for General harbor environment. However, four substances (Isocyanuric acid, Tribromomethane, Chloropicrin and Monochloroacetic acid) were exceed 1 for Nearship environment. But observed toxicity in the test water on algal growth inhibition would be mitigated by normal dilution factor of 5 applied for nearship exposure. Thus, our results of WET testing and ERA showed that the BWMS effluent treated by NaDCC injection method would have no adverse impacts on marine environment.

• Environmental Analysis Health and Toxicology
• /
• 제27권
• /
• pp.12.1-12.8
• /
• 2012

Objectives: The aim of this study was to identify the health and environmental risk factors of air contaminants that influence environmental and respiratory diseases in Gyeongju, Pohang and Ulsan in South Korea, with a focus on volatile organic compounds (VOCs). Methods: Samples were collected by instantaneous negative pressure by opening the injection valve in the canister at a fixed height of 1 to 1.5 m. The sample that was condensed in $-150^{\circ}C$ was heated to $180^{\circ}C$ in sample pre-concentration trap using a 6-port switching valve and it was injected to a gas chromatography column. The injection quantity of samples was precisely controlled using an electronic flow controller equipped in the gas chromatography-mass spectrometer. Results: The quantity of the VOC emissions in the industrial area was 1.5 to 2 times higher than that in the non-industrial area. With regards to the aromatic hydrocarbons, toluene was detected at the highest level of 22.01 ppb in Ulsan, and chloroform was the halogenated hydrocarbons with the highest level of 10.19 ppb in Pohang. The emission of toluene was shown to be very important, as it accounted for more than 30% of the total aromatic hydrocarbon concentration. Conclusions: It was considered that benzene in terms of the cancer-causing grade standard, toluene in terms of the emission quantity, and chloroform and styrene in terms of their grades and emission quantities should be selected for priority measurement substances.

• 한국환경보건학회지
• /
• 제45권1호
• /
• pp.54-61
• /
• 2019

Objectives: In this study, we investigated an assessment for exposure levels of hazardous substances to kids cafes that unregulated by law. Methods: Heavy metals, volatile organic compounds, formaldehyde, pesticides and phthalate were measured at 20 kids cafes in Gyeonggi-do and Incheon. Samplings were conducted from April to July in 2018. Results: Heavy metals were detected over the standard mainly around the floor and walls in the 19 kids cafes. Pesticides were detected in 7 locations with chlorpyrifos, diazinon and cypermethrin, and showed the highest detection level of chlorpyrifos. The concentrations of DEHP in all kids cafes were exceeded with standard. The risk assessment results showed that HCHO as carcinogen had a safety level and DEHP as non-carcinogens had a safety level as assessed to be under than 0.1. Conclusions: Considering the exposure investigation results and the importance of child health protection, kids cafe should be included in the legal management list of children's activities zones.