• Fisheries and Aquatic Sciences
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• 제15권4호
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• pp.337-343
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• 2012

The Korean bottom trawl survey was conducted using a trawl designed by the National Fisheries Research and Development Institute (NFRDI). The capture efficiency and size selectivity of this trawl for snow crab Chionoecetes opilio was investigated by experimental tows. An auxiliary sampling net (underbag) was attached beneath the trawl net to capture crabs escaping under the trawl footrope. Experimental tows were made by the same vessel speed (3.4 knots) as in the bottom trawl survey, but toing time was shortened from the standard 30 min to 10 min to reduce possible trawl distortion due to the high catch rate of mud and debris in the underbag. In averaged over 17 tows conducted between 110-383 m depth, trawl efficiency of both males and females combined increased from about 10% at 20 mm (carapace width) to about 70% at 100 mm, with a width of 50% capture equal to 78 mm.

• 한국대기환경학회지
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• 제21권2호
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• pp.145-153
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• 2005

An electret fiber with a dipole charge distribution was used to capture charged ultrafine particles in this study. Brownian diffusion and Coulombic force are the dominant collection mechanisms in the electret filtration of charged ultrafine particles. The interaction between Brownian diffusion and Coulombic force for the deposition of ultrafine particles onto a dipolarly charged fiber is studied by solving the convective diffusion equation including Coulombic force as an external force, and the numerical results are compared with the experimental data. As a result, it is shown that there is a negative interaction between Brownian diffusion and Coulombic force, i.e., Coulombic capture efficiency is reduced with decreasing Pe. These results suggest that Brownian diffusion and Coulombic capture efficiency, $\eta$$_{CD}$ is not a simple sum of Brownian diffusion efficiency, $\eta$$_{D}$ and Coulombic capture efficiency, $\eta$$_{C}$.

• 대한기계학회논문집B
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• 제38권2호
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• pp.165-172
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• 2014

단일 노즐을 이용하는 $CO_2$ 포집용 분무탑의 기본적 특성을 실험적으로 구하였다. 다양한 조건 - 주입 기체 유량 및 농도, 주입 흡수제 유량 및 농도 등 - 에서 얻어진 포집성능을 포집효율 뿐만 아니라 재생에너지의 주요 결정요인인 $CO_2$ 포화도 측면에서 검토하였다. 다양한 조건들에서의 포집효율 변화는 흡수제($NH_3$)와 $CO_2$의 상대적 유량비만의 단조증가함수로 잘 표현되었다. 포집후의 흡수제의 $CO_2$ 포화도 또한 $NH_3/CO_2$ 유량비만의 함수로 잘 정리가 되었으나, 포집효율과는 다르게 단조감소함수를 보였으며, 특히 $CO_2$ 포화도와 포집효율과의 상관관계를 보면 기존의 모든 연구들에서 포집효율이 증가할수록 $CO_2$ 포화도가 감소하였다. $CO_2$ 포화도는 낮은 포집효율 조건에서 최대 20-25% 수준이었으나, 90% 이상의 고효율에서는 10% 미만으로 매우 낮았다. 이는 높은 포집효율을 위해 사용되는 흡수제의 양이 과도하며, 다시 재생에너지가 과도하게 필요함을 의미한다.

• 한국입자에어로졸학회지
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• 제10권2호
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• pp.45-51
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• 2014

Fine particle capture is facing a challenge since traditional filtration which relies on the combination of impaction, interception, diffusion has a limited efficiency for fine particle capture particularly in size from 0.1 to $0.5{\mu}m$. This paper reviewed the collection efficiency of above mechanisms, as well as magnetic mechanisms for ferromagnetic particles, and mainly studied the influencing factors of magnetic filtration. Filtration velocity, magnetic field intensity and fiber size were found to be the most important parameters for magnetic filtration.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 춘계학술발표논문집
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• pp.888-890
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• 2009

This study presented a lab-scale apparatus for turbidity control in the lakes or reservoirs. Overall, the filamentous mat had a capture efficiency of 70~90% compared with the control group. Generally, the capture efficiency decreased with improved input turbidity flux. However, the attachment and sedimentation were thought to be the main processes for turbidity water retention and removal. Thus, the increase of hydraulic detention time in the mat zone is very important to improve the capture efficiency of the turbidity water.

• 한국수산과학회지
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• 제28권6호
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• pp.708-719
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• 1995

This study is to estimate abundance of the Chesapeake Bay blue crab stock. Using 823 dredge tows which were conducted during the 1991 winter survey, blue crab abundance was estimated on the basis of newly developed methods which account for unequal dredge tow distances, size- and sex-specific heterogeneous overwintering spatial distributions, wintertime exploitation, the time period of quasi-hibernation, and dredge capture efficiency. The estimate of total abundance before correction by gear efficiency was 131.8 million crabs $(95\%\;C.I.\;=\;118.2\;million\;crabs\;to\;145.4\;million\;crabs),$ Dredge capture efficiency was estimated to be 0.474. Thus, the estimate of total abundance was calculated as 278.1 million crabs after correction by the efficiency factor.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2971-2976
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• 2008

Recently, there has been growing interest in the oxyfuel combustion cycle since it enables high-purity CO2 capture with high efficiency. However, the oxyfuel combustion cycle has some important issues regarding to its performance such as the requirement of water recirculation to decrease a turbine inlet temperature and proper combustion pressure to enhance cycle efficiency. The purpose of the present study is to analyze performance characteristics of the oxyfuel combustion cycle with different turbine inlet temperatures and combustion pressures. It is expected that the turbine inlet temperature improves cycle efficiency, on the other hand, the combustion pressure has specific value to display highest cycle efficiency.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.516-521
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• 2012

본 연구는 연소기체로부터 $CO_2$ 기체를 포집하는 기포 유동층 흡착 및 재생 반응기 공정의 주요 운전변수의 영향을 조사하기 위해서 단순화된 공정모델을 개발하였다. 반응속도와 반응기에서 고체입자의 평균체류시간을 이용하여 흡착탑과 재생탑에서 각 반응 전환율을 계산하였다. 실험실 규모 기포 유동층 공정에 적용하여 $CO_2$ 포집효율에 대한 온도, 기체유속, 고체순환속도, 연소기체 중 수분농도의 영향을 조사하였다. $CO_2$ 포집효율은 흡착탑의 온도 혹은 유속이 증가함에 따라서 감소하였다. 그러나 연소기체의 수분농도 혹은 재생탑의 온도가 증가함에 따라서 증가하였다. 계산된 $CO_2$ 포집효율은 측정값과 잘 일치하였다. 그러나 본 모델은 $CO_2$ 포집효율에 대한 고체순환속도의 영향과 잘 일치하지 않았다. 이의 해석을 위해서는 기체-고체 접촉효율에 대한 이해가 더 필요하였다.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.3979-3989
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• 2021

Several parametric effects on the magnetic collection have been evaluated considering dimension, strength of external magnetic field, injected velocity and particle concentration in the working fluid. Besides, accidental environments, expected in the containment of nuclear power plants, have also been addressed for the capture efficiency. The capture efficiency is especially enhanced with magnetic particle size and magnetic field strength through increased magnetic force; the non-magnetic coating thickness and fluid velocity hinder the magnetic collection. Based on the assessment, the magnetic withdrawal system can effectively capture magnetic particles even under accidental environments. Withdrawal of multifunctional magnetic particles or filtering of magnetic impurities can be effectively realized through the system.

• 한국대기환경학회지
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• 제30권3호
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• pp.261-269
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• 2014

This study focused on the performance of the newly developed hybrid filter system to capture fine particulate matter and mercury compounds in a coal-fired power plant. The hybrid filter system combining bag-filter and electrostatic precipitator had been developed to remove fine particulate matter. However, it would have a good performance to control mercury compounds as well. In Hybrid filter capture system, the total removal efficiency of total mercury compounds consisting of particulate mercury ($Hg_p$), oxidized mercury ($Hg^{2+}$), and elemental mercury ($Hg^0$) was 66.2%. The speciation of mercury compounds at inlet and outlet of Hybrid filter capture system were 1.3% and 0% of $Hg_p$, 85.2% and 68.1% of $Hg^0$, and 13.5% and 31.9% of $Hg^{2+}$, respectively. In hybrid filter capture system injected with 100% of flue-gas, the removal efficiency of total mercury was calculated to increase to 93.5%.