• 한국대기환경학회지
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• 제15권6호
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• pp.805-812
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• 1999

Adsorption characteristics of volatile organic compounds(VOCs) by activated carbon fiber(ACF) were investigated using a continuous system for benzene, toluene, xylene(BTX) generation. Studied characteristics for adsorption were equilibrium capacity, accumulative adsorption, and breakthrough curve. Operating variables were adsorption temperature(25~45$^{\circ}C$) and partial pressure(1.2~12 mmHg) of BTX. The experimental results show that the adsorption equilibrium capacity increases with increasing partial pressure of BTX and decreases with increasing temperature. It was also found that the break point was decreased with increasing partial pressure, temperature and gas flow rate due to an effect of mass transfer of adsorbate.

• 한국표면공학회지
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• 제40권2호
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• pp.59-62
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• 2007

Metal containing hydrogen free nanocrystalline structured carbon (Me:nc-C) films were synthesized by closed-field unbalanced magnetron sputtering system (CFUBM). The aim of this study was to determine the relationship between the microstructure and physical properties of Me:nc-C films as a function of the concentration of materials. The film structures were examined by x-ray photoelectron spectroscopy and high resolution transmission electron microscopy. The physical properties of the Me:nc-C films were evaluated by using a 4-point probe. The fraction of graphite clusters was found to be increased by containing titanium and the electrical resistivity decreased with increasing amount of containing.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
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• pp.202-206
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• 2004

The objectives of this study are to investigate the relationship between the silver ion concentrations released from the point-of-use(POU) water purification devices installed silver impregnated activated carbon filters and the antibacterial activities against HPC bacteria. Total of 68 POU devices were tested. The concentrations of the eluted silver ion from the silver impregnated activated carbon filter showed the range from $4\;{\mu}g/L$ to $386\;{\mu}g/L$, and the HPC bacteria were found to diversely grow within the range 0-5,200 cfu/mL. The average silver concentrations released from UF units system and RO units system were $30\;{\mu}g/L$ and $73\;{\mu}g/L$, respectively. And the number of colonies were reduced significantly as the elution levels of silver exceeded $100\;{\mu}g/L$, however silver ions below the concentration of $100\;{\mu}g/L$ were not particularly effective for eradicating HPC bacteria from water.

• 한국물환경학회지
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• 제27권6호
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• pp.877-884
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• 2011

In this paper, the removal characteristics of dissolved organic carbon (DOCs) by micro bubble ozonation process and $O_3/UV$ process were comparatively studied. In the point of DOC removing reaction coefficient, micro bubble ozonation system and $O_3/UV$ process had not significant difference, $0.0120sec^{-1}$ and $0.0141sec^{-1}$. Therefore micro bubble ozonation process is more suitable for tertiary treatment of sewage in the point of installation and maintenance cost-reducing. The optimum ozone injection rate was 2.0 g $O_3/g$ DOC and HRT was 3 min for the micro bubble ozonation process. The removal efficiency of DOC and SUVA in micro bubble ozonation system was 32.8% and 58.3% respective. Biological aerated filter (BAF) process was installed to remove soluble organic material increased by micro bubble ozonation system. And the effluent BOD of BAF was below 1.0 mg/L. In the view of cost-effectiveness, $O_3/BAF$ process was more profitable than $O_3/UV/BAF$ process for tertiary treatment of sewage. In order to nitrify ammonia in the BAF process completely, $NH_4{^+}-N$ concentration in the influent water of BAF should be designed considering low water temperature in the winter season.

• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.212-219
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• 2017

As an environmental pollution and global warming due to an excessive carbon emission are intensified, the importance of renewable energy is in rise today. TCP (Tidal Current Power), one of the renewable energy sources, generates electricity by converting kinetic energy of current into rotational energy of turbine. Also the TCP has a great advantages of predictability and reliability. Because the generating power is proportional to cubic of stream velocity, amplifying current speed by applying duct is highly effective to increase the generating power. SPM (Single Point Mooring) can be applied for the weather vane with various current direction and also augments generating power of the system. In addition, simple installation and retrieval could be a merit of SPM system. By combining duct and SPM, TCP system for relatively low-speed-current and shallow water region can be feasible and economical. In this study, single point moored duct-type TCP system was designed and the motion of submerged structure was investigated in both numerical and experimental method. DNV wadam V4.8-1 and OrcaFlex 10.0a were used for the frequency and time domain motion analysis of system respectively. Duct model scaled by 0.05 of Froude conformity ratio and CWC (Circulate Water Channel) are used for experiment.

• 폴리머
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• 제25권3호
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• pp.435-440
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• 2001

본 연구에서는 일방향 탄소/탄소 복합재료에 산화억제제로 사용된 $MoSi_2$의 첨가량에 따른 복합재료의 부착력, 파괴인성 그리고 충격강도와의 관계를 고찰하였다. 산화억제제로 사용한 이규화 몰리브덴 (MoSi$_2$)은 복합재료의 내산화 특성을 향상시키기 위하여 각각 4, 12, 20wt%의 중량비로 페놀수지에 함침시켰다. 본 연구에 있어서 복합재료의 부착력은 접촉각 측정에 의한 Wilhelmy 방정식을 사용하여 계산하였다. 파괴인성과 충격강도는 임계 세기인자 측정을 위한 3점 굴곡 시험 방법과 Izod 충격시험에 의해 각각 측정하였다. 그 결과, $MoSi_2$가 첨가된 탄소/탄소 복합재료의 파괴인성과 충격강도는 증가하였다. 특허 l2wt%의 $MoSi_2$가 첨가된 복합재료가 London dispersive 요소($W_A\;^L$)의 증가에 의한 가장 큰 부착력을 나타내었으며, 이는 복합재료의 각 구성요소간의 계면결합력 증가에 따른 결과라 사료된다.

• 한국해양환경ㆍ에너지학회지
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• 제13권2호
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• pp.121-125
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• 2010

지중 저장기술은 대기로 방출되는 이산화탄소를 저감하는 기술로서 기후변화를 발생하는 온실효과를 저감 시킬 수 있다. 해양 저지대에 위치한 심층 대수층 혹은 폐유전 등은 이러한 이산화탄소 저장기술의 중요한 후보군이라고 할 수 있다. 관련된 이산화탄소 주입 및 저장기술은 전 세계적으로도 많은 관심을 받고 있으나, 이러한 시스템에서 이산화탄소 누출이 발생하였을 때의 부정적 영향에 대해서는 아직 심도 있는 연구는 진행되지 못하고 있다. 이산화탄소 저장기술의 안정성이 매우 높아서 누출의 가능성은 매우 낮다고 하더라도, 고농도의 이산화탄소가 만약의 사태에서 누출이 된다면 여전히 해양생태계 및 환경에 위험이 있을 수 있다. 그러나 이에 대한 연구가 충분히 이루어지지 않았기에, 본 연구에서는 하나의 신뢰성 및 위해성 평가방법을 소개하고자 한다. Feature, Event and Process(FEP)를 통해 다양한 요소를 고려하고, 결함수 분석을 통해 신뢰도를 평가하는 방법을 제안한다. 이러한 FEP 분석으로 시스템에서 시공 및 운영과정에서 발생할 수 있는 다양한 누출 가능성을 평가하는 방법을 소개하였다.

• 상하수도학회지
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• 제22권6호
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• pp.697-704
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• 2008

Stormwater runoff from urban road area as non-point source has a tendency of including lots of pollutants at initial rain period. Recently, there are several cases of having installed treatment facilities for reducing pollution discharge from the impervious cover in urban area to prevent watershed environment from getting worse. The filtration type among non-point source treatment systems has been known as one of the most efficient system for treatment of non-point source pollutants. Therefore, various kinds of filter media such as expanded polypropylene(EPP), granular activated carbon, zeolite, perlite, illite, sand, gravel has been developed. This study was conducted to verify performance and hydraulic characteristics of filter media as measures for non-point source. The experiment was carried out to evaluate applicability and variation of 4 kind of most popular filter media(EPP, GAC, Zeolite, Perlite) in headloss with elapsed time and influent flow rate and to obtain data base that could be used to establish management plan for road runoff treatment. In experiment by tap water, it showed that EPP and perlite those are floatable materials showed stable operating performance and lower headloss than the others.

• 한국진공학회지
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• 제20권5호
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• pp.374-380
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• 2011

니켈촉매 막을 증착시킨 산화규산 기판위에 아세틸렌기체와 수소기체를 원료로 육불화황기체를 첨가기체로 탄소코일을 증착하였다. 육불화황이 투입되는 단계에 따라 성장된 탄소코일의 특성(형성 밀도, 형상)을 조사하였다. 육불화황을 연속적으로 주입하였을 경우 선형, 마이크로크기 코일, 나노크기 코일, 그리고 파동형 나노크기 코일 등 다양한 형태의 탄소코일들이 성장하였다. 하지만, 탄소코일 초기 증착단계에서 1분정도의 짧은시간 동안 육불화황을 주입한 경우 나노크기의 탄소코일 형상만을 대부분 얻을 수 있었다. 탄소코일 합성반응시간이 1분 정도 지체된 후의 단계에서 짧은시간 동안의 육불화황 주입은 코일형상 제어를 저해하였다. 따라서, 육불화황의 주입 시간과 주입단계가 탄소 코일의 형상을 결정하는 중요한 요인임을 알 수 있었다.

• 원예과학기술지
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• 제30권5호
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• pp.501-508
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• 2012

Reducing carbon dioxide ($CO_2$) exhaust has become a major issue for society in the last few years, especially since the initial release of the Kyoto Protocol in 1997 that strictly limited the emissions of greenhouse gas for each country. One of the primary sectors affecting the levels of atmospheric greenhouse gases is agriculture where $CO_2$ is not only consumed by plants but also produced from various types of soil and agricultural ecosystems including greenhouses. In greenhouse cultivation, $CO_2$ concentration plays an essential role in the photosynthesis process of crops. Optimum control of greenhouse $CO_2$ enrichment based on accurate monitoring of the added $CO_2$ can improve profitability through efficient crop production and reduce environmental impact, compared to traditional management practices. In this study, a sensor-based control system that could estimate the required $CO_2$ concentration considering emission from soil for cucumber greenhouses was developed and evaluated. The relative profitability index (RPI) was defined by the ratio of growth rate to supplied $CO_2$. RPI for a greenhouse controlled at lower set point of $CO_2$ concentration (500 ${\mu}mol{\cdot}mol^{-1}$) was greater than that of greenhouse at higher set point (800 ${\mu}mol{\cdot}mol^{-1}$). Evaluation tests to optimize $CO_2$ enrichment concluded that the developed control system would be applicable not only to minimize over-exhaust of $CO_2$ but also to maintain the crop profitability.