• Analytical Science and Technology
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• v.31 no.3
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• pp.134-142
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• 2018

The uranium isotopic ratio in environmental samples around nuclear facilities is important because it reveals information regarding illegal activities or anthropogenic pollution. Determination of uranium isotopes, however, is a challenging task requiring much labor and time because of the complex separation procedures and lengthy process. In this study, a rapid determination method for uranium isotopes in environmental samples was developed using. The sample was completely decomposed using the alkali fusion method. The separation procedure using extraction chromatography (UTEVA) was simplified in a single step without any further removal process for Si and major matrix elements. The established method can be completed within 3 h from sample dissolution to ICP-MS measurement. Most matrix elements and uranium isotopes in the soil samples were well separated and purified. Five types of were used to assess the method's accuracy and precision for a rapid uranium analysis method. The analytical accuracy for all CRM samples ranged from 95.1 % to 97.8 %, and the relative standard deviation was below 3.9 %. From the analytical results, one may draw conclusions that the evaluated method for uranium isotopes using alkali-fusion, the extraction chromatography process, and ICP-MS measurements is fast and fairly reliable owing to its recovering efficiencies. Thus, it is expected that the evaluated method can contribute to the improvement of environmental monitoring ability.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.207-215
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• 2006

The characteristic floc growth of Al-based coagulants was investigated in the aspect of mixing intensity and visualization of generated flocs during coagulation and flocculation processes. Zeta potential of turbid particles in the artificial water nearly approached to zero at pH 8-9, in which TDS and conductivity were minimized. The removal rate of turbidity and phosphate was maximized at the optimal mixing intensity of rapid and slow mixing stages. After the rapid mixing stage of coagulation process, small particles ($3-5{\mu}m$) were abruptly generated, and higher mixing intensity made more numbers of flocs. With the progress of slow mixing stage, the number of small particles were decreased with the simultaneous increase of intermediate particles ($7-21{\mu}m$). The number of large particles (>$23{\mu}m$) were maximized at the lowest rapid mixing intensity of $95.1sec^{-1}$, whereas small particles (<$5{\mu}m$) were maximized at the highest rapid mixing intensity of $760.7sec^{-1}$.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.18-26
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• 2008

Behavior and decomposition velocity of pollutants on various forms from domestic sewage in sewage treatment plant were investigated in order to obtain the basic data for improving the removal efficiency of pollutants and to reduce the area in constructed wetland by natural purification method. The removal amounts of BODs and CODs in aerobic bed were significantly higher than those of the other beds. In aerobic bed, the removal amounts of IBOD and ICOD were more than those for SBOD and SCOD, respectively, whereas the removal amounts of BODs and CODs in anoxic and anaerobic beds were little different. The removal amounts of SSs in aerobic bed were also higher than those for the other beds, and the removal amounts of VSS in all beds were more than those for FSS. The removal amounts of DTN and DTP in all beds were more than those for STN and STP, respectively. In addition, the decomposition velocities of TBOD, TCOD and TSS in aerobic bed were 30.79, 17.15 and 29.96 $day^{-1}$. Moreover, the decomposition velocities of BODs, CODs and SSs in aerobic bed were very rapid than those in the other beds. On the other hand, the decomposition velocities of BODs, CODs and SSs in anoxic and anaerobic beds were a little different regardless of the forms of pollutant. The decomposition velocities constants of T-N in aerobic, anoxic and anaerobic beds were 4.78, 0.12 and 0.10 $day^{-1}$, respectively. Moreover, the decomposition velocities constants of T-P in aerobic, anoxic and anaerobic beds were 13.09, 0.12 and 0.13 $day^{-1}$ respectively. The decomposition velocity of T-Ns and T-Ps in aerobic bed were slightly rapid than those in the other beds, whereas the decomposition velocities of T-Ns and T-Ps in anoxic and anaerobic beds were slightly different regardless of the forms of pollutant.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.93-98
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• 1976

The experiment was made to investigate concentrations of $CO_2\;and\;O_2$ in the removal of astringency of persimmon fruits and to study the changes of total, reducing sugar and hardness during the removal of astringency. 1. During the removal of astringency of persimmon fruits, channel of tannin content showed the rapid decrease in high concentration of $CO_2$ and the gradual decrease in low concentration of $CO_2$. 2. Concentration of oxygen did not show effect on the removal of astringency at high concentration of $CO_2$ but at low concentration of $CO_2$ in Chungdo-Bansi. 3. Optimal concentration of the removal of astringency was $60{\sim}70%,\;CO_2$ and $6{\sim}8%\;O_2$ in Chungdo-Bansi and Sagoksi 4. In changes of sugar content total sugar was decreased and reducing sugar was increased.

• Food Science and Preservation
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• v.6 no.4
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• pp.392-397
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• 1999

The quality changes during the removal of astringecy by CO$_2$gas at 2$^{\circ}C$ and 20$^{\circ}C$ of three varieties of persimmons named 'Tonewase', 'Chungdobanshi' and 'Sagokshi' were examined. Astringency index and tannin content showed rapid decrease at 20$^{\circ}C$ and gradual decrease at 2$^{\circ}C$. All was edible 2days from the removal of astringency at 20$^{\circ}C$, while 'Tonewase' and 'Sagokshi' were edible on 6days and 'Chungdobanshi' on 10days after treatment at 2$^{\circ}C$. Soluble solid contents was decreased a little(1∼3%) during the removal of astringency. Hardness was decreased slowly but, kept over 1.0kg/$\phi$5mm till edible period in all varieties at 2$^{\circ}C$ and 20$^{\circ}C$. The hardness of 'Chungdobanshi' was kept well after the removal of astringency at 2$^{\circ}C$. No noticeable color changes in all varieties during treatment. Injury fruits were noticeable in only 'Tonewase' after the removal of astringency treatment at 2$^{\circ}C$.

• Journal of Forest and Environmental Science
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• v.14 no.1
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• pp.101-111
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• 1998

Sedimentation characteristics SS, $BOD_5$ and removal efficiency of waste water in the tissue paper mill using milk carton were examined. Optimum dosage of coagulant, rapid mixing time and slow mixing time were determined by turbidity, SS and S-$BOD_5$ and then equation for treatment efficiency was suggested. For the coagulant, polyaluminium chloride(PAC) are compared with a little better efficiency compare to the aluminium sulfate.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.605-612
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• 2005

The objective of this study was to evaluate the factors affecting the optimization of coagulation hybrid UF membrane processes for the reuse of secondary effluent from sewage treatment plant. The experimental results obtained from the UF membrane process showed that organic colloids in the size range of $0.2{\mu}m{\sim}1.0{\mu}m$ caused the most substantial influence on the fouling of UF membrane. When using a coagulation pretreatment to UF membrane, alum dosage of 50mg/L resulted in the least reduction in membrane permeate flux. Also, for the rapid mixing process, in-line mixer type was more efficient for organic removal than back mixer type. Therefore, it may be concluded that coagulation-UF hybrid membrane process comparing to UF alone process showed not only higher removal efficiency of organic matter, but also substantial improvement of permeate flux of UF membrane.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.48
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• pp.57-76
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• 2010

This study reviews maritime transport policy regarding liner conference and the changes in the liner market over the decades. Liner shipping industry has long been protected from competition by block exemption. To prevent excessive competition in punctual operation and its inelastic market structure, liner shipping companies formed conferences that are protected to fix the prices under the law. In the US, deregulation in transport sector began from 80's and continuing with OSRA 1998, conferences were dissolving. On the other hand, the EU with close conference system, Regulation 4056/86 contained block exemption remained in force for unlimited time without review clause. However, in Oct 2008, the EU has announced its removal, and conferences were no longer permitted to fix the price nor exchange information. Although OSRA 1998 has already broken up conferences by allowing individual service contracts, but the repeal of the immunity for price fixing will alter significantly the rule on cooperation in the industry since it is a unilateral move by the EU, especially in transatlantic lane. There are rapid changes in shipping market getting much more complicated, and with removal of 4056/86 allowing the market to be more competitive, opening up the industry with far more diverse strategic options. Hence this paper reviews on liner shipping industry and its changes of policies over the years from protected market to open competition market of today.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.889-894
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• 2009

Accompanied by the rapid development of Computer Vision, Visual surveillance has achieved great evolution with more and more complicated processing. However there are still many problems to be resolved for robust and reliable visual surveillance, and the cast shadow occurring in motion detection process is one of them. Shadow pixels are often misclassified as object pixels so that they cause errors in localization, segmentation, tracking and classification of objects. This paper proposes a novel cast shadow removal method. As opposed to previous conventional methods, which considers pixel properties like intensity properties, color distortion, HSV color system, and etc., the proposed method utilizes observations about edge patterns in the shadow region in the current frame and the corresponding region in the background scene, and applies Laplacian edge detector to the blob regions in the current frame and the background scene. Then, the product of the outcomes of application determines whether the blob pixels in the foreground mask comes from object blob regions or shadow regions. The proposed method is simple but turns out practically very effective for Gaussian Mixture Model, which is verified through experiments.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.71-77
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• 2016

Air pollutants nitrogen oxides are inevitably generated in the combustion reaction. Its amount trend is steadily increasing because the rapid modern industrialization and population growth. For this reason, NOx is controlled to reducing the harmful components in the exhaust gas. So Marine Environment Protection Committee (MEPC) take effect 'Tier I', 'Tier II' of air pollution regulation in 2005 and 2011 respectively. According to NOx emissions are strictly regulated management of the vessel through them. In addition, since 2016 the regulation enter into force in the next step 'Tier III' was confirmed by MEPC 66th committee. It's 80% enhanced emissions limits than the 'Tier I' Alternatively these emission regulation, research is actively being carried out about exhaust gas after-treatment methods through the vessel application of Selective Catalytic Reduction(SCR). Therefore depending on the basic specification of cell density according to the Area velocity, Space velocity, Linear velocity is studied the effects of NOx removal efficiency