• 한국환경과학회지
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• 제17권8호
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• pp.833-840
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• 2008

Deoxygenation process in which CBOD(carbonaceous BOD) is biochemically oxidized to reduced inorganic compounds is of great significance in the oxygen demand of stream waters. The CBOD decay rate has traditionally been determined in a laboratory by CBOD bottle incubation method. But in this study, CBOD decay rates were obtained by laboratory incubation method and natural waters experiment. Average CBOD decay rate for the Nakdong river(upper zone) in natural waters were 0.553 $day^{-1}$ during April 2005 to January 2007. The values in the middle and down parts of the Nakdong river in natural waters were 0.384 $day^{-1}$ and 0.252 $day^{-1}$ at the same period of time, respectively. Average CBOD decay rates using by incubation method in the upper/middle/down parts of the main stream in the Nakdong river basin was 0.270 $day^{-1}$, and 0.289 $day^{-1}$, and 0.283 $day^{-1}$ during April 2005 to January 2007, respectively.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.517-523
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• 2003

방사선장 하에서의 탈기막 재질의 물성에 미치는 방사선의 영향에 관한 연구를 수행하였다. PP에 미치는 방사선속을 계산하기 위해 MCNP4A Code를 이용하였으며 MCNP4A Code를 이용한 광자선속을 계산하기 위하여 탈기장치와 PP 막을 봉 구조로 규격화하였다. 양단차폐 계통에 사용되는 탈기막 재질인 PP의 변형은 계통수의 방사능이 매우 낮기 때문에 거의 없을 것으로 평가되었으며 작업자의 피폭도 무시할 정도인 것으로 판단되었다. 검토결과, 원자력발전소의 원자로 계통수 처리를 위해 방사선장하에서 노출되는 폴리프로필렌 탈기막의 재질은 건전성이 그대로 유지될 수 있음을 평가하였다.

• 물과 미래
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• 제17권2호
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• pp.85-97
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• 1984

Measuring the river flow and water quality in the midstream of the Nakdong River, the natural purification status in examined through the analyses of the elements which affect the variation of dissolved oxygen, and DO model is evaluated to the midstream reach of the river. The major results of this study are as follows; the pruification factor of the of the river is relatively high, it is worried over eutrophication considering much production of algae, and it is evaluated that important factor affecting the DO value computed by the proposed DO model are in order of reaeration coefficient, carbonaceous BOD and deoxygenation constant.

• Bulletin of the Korean Chemical Society
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• 제13권1호
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• pp.48-53
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• 1992

The reactions of ${\beta}-aryl-{\alpha},{\beta}-epoxy$ silanes with magnesium bromide or magnesium iodide in the presence of excess magnesium in ether at room temperature afforded vinylsilanes in 18-100% yields. E-Vinylsilanes were predominant over Z-isomers (> 80%) regardless of the stereochemistry of ${\alpha},{\beta}-epoxy$ silanes.

• 한국수산과학회지
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• 제20권1호
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• pp.69-78
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• 1987

인간생활에 의하여 발생되는 유기폐수 및 폐기물로 인한 연안오염을 저감시키고, 분해부산물로 생성되는 무기영양염을 이용하여 해역의 생산력을 높일 수 있도록 이들을 해류소통이 원활하고 수심깊은 외해에 투기할 경우 투기가능량을 산출하기 위하여 1986년 하계 3개월동안 동해남부해역을 대상으로 관측 및 실험을 행하였다. 허용농도산출은 Streeter-Phelps의 model을 이용하였으며 이 model의 인자인 산소소모속도당수는 산소소모법으로 구하였고, 산소교환계수는 폐쇄계 model을 적용하여 현장관측을 통해 산출하였다. 표층에서 각 수심까지의 산소소모속도상수는 $0.177\times0.313/day$였으며 산소교환계수는 $0.025\~0.364/day$이었다. 이들 인자를 이용하여 해역의 용존산소를 5mg/l 이상으로 유지할 수 있는 투기가능량은 $42.29\~434.25g\;BOD/m^2$의 범위였으며 결과는 혼합 수심에 크게 의존됨을 고찰할 수 있었다.

• Nuclear Engineering and Technology
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• 제31권6호
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• pp.541-547
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• 1999

Corrosion control, in the end-shield cooling system of Wolsung Nuclear Power Plant, is directly related to the control of dissolved oxygen (DO). The current method, being used to deoxygenate the end-shield cooling water, is a chemical treatment by addition of reducing agent, hydrazine, to react with DO. This method has several limitations including high reaction temperature of hydrazine , unwanted explosive hydrogen gas production, and its intrinsic harmful property. A new approach to remove DO using a membrane-based oxygen removal system (MORS) was tried to overcome limitations of the hydrazine treatment. The DO removal efficiency of the MORS was found to be in the range 87% to 98%: The higher vacuum, the lower water flow rate and the higher water temperature tend to increase the DO removal efficiency.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1951-1955
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• 2014

Catalytic pyrolysis of Geodae-Uksae 1, a kind of miscanthus found in Korea, was carried out over mesoporous MCM-48 catalysts. For rapid product analysis and catalyst evaluation, pyrolysis-gas chromatography/mass spectrometry was used. X-ray diffraction, nitrogen sorption, pyridine adsorbed Fourier transform infrared, and NH3 temperature programmed desorption were utilized to analyze the properties of the catalysts. Compared to non-catalytic reaction, catalytic upgrading over mesoporous Al-MCM-48 catalysts produced a higher-quality bio-oil with a high stability and low oxygen content. Al-MCM-48 exhibited higher deoxygenation ability than Si-MCM-48 due to its higher acidity.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.187-192
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• 1998

The cis- and trans-diastereomers of the 7,8-dihydro-7-deazapurine derivatives were synthesized from the corresponding diastereomers of 4-tran5-cyano-2-methyl-3-phenyl-5-oxopyrrolidine (5), which were reduced from the 2-cis- and 2-tran5-diastereomers of 4-trans-cyano-2-hydroxymethyl-3-phenyl-5-oxopyrrolidine (2) via tosylation, iodination and following elimination respectively. The prepared cis- and ttans-diastereomers of 6-amino-2-mercapto-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (8) were transferred to the corresponding 2-methylthio-diastereomers 9 and following desulfurization with Raney-nickel leaded to the cis and trans-diastereomers of 6-amino-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (10), respectively. The synthesized 7-deazapurine derivatives were tested for their antibiotic activity by the serial two-fold dilution method.

• 공업화학
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• 제30권6호
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• pp.707-711
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• 2019

The feasibility of waste concrete as a catalyst for the effective pyrolysis of polyethylene terephthalate (PET) was examined using thermogravimetric (TG) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) analyses. TG analysis results indicated that the maximum decomposition temperature of PET is not altered by the use of waste concrete, showing similar values (407 ℃ and 408 ℃ at 5 ℃/min). Meanwhile, the volatile product distribution data obtained from the Py-GC/MS analysis revealed that the use of waste concrete promoted the deoxygenation reaction via converting the oxygen containing products such as benzoic acids, benzoates, and terephthalates to valuable deoxygenated aromatic hydrocarbons including benzene, toluene, ethylbenzene, and styrene. This suggests that the waste concrete can be used as a potential catalyst for the production of valuable aromatic hydrocarbons from PET pyrolysis.

• 한국수산과학회지
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• 제29권6호
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• pp.787-796
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• 1996

The biodegradation experiment, the TOD analysis and the element analysis for dispersant, Bunker-A oil and Bunker-B oil were conducted to study the biodegradation characteristics of a mixture of Bunker-A oil with dispersant and a mixture of Bunker-B oil with dispersant in the seawater. The results of biodegradation experiment showed 1mg of dispersant to be equivalent to 0.26 mg of $BOD_5$ and to 0.60 mg of $BOD_{20}$ in the natural seawater. The results of TOD analysis showed each 1 mg of dispersant, Bunker-A oil and Bunker-B oil to be equivalent to 2.37 mg, 2.94 mg and 2.74 mg of TOD, respectively. The results of element analysis showed carbon, hydrogen, nitrogen and phosphorus contents of dispersant to be $82.1\%,\;13.8\%,\;1.8\%\;and\;2.2\%$, respectively. Carbon and hydrogen contents of Bunker-A oil were found to be $73.3\%\;and\;13.5\%$, respectively, and carbon, hydrogen and nitrogen contents of Bunker-B oil to be $80.4\%,\;12.3\%\;and\;0.7\%$, respectively. Accordingly, the detection of nitrogen and phosphorus in dispersant shows that dispersants should be used with caution in coastal waters, with relation to eutrophication. The biodegradability of dispersant expressed as the ratio of $BOD_5/TOD$ was found to be $11.0\%$. As the mix ratios of dispersant to Bunker-A oil (3 mg/l) and a mixture of Bunker-B oil (3mg/l) were changed from 1 : 10 to 5 : 10, the biodegradabilities of a mixture of Bunker-A oil with dispersant and Bunker-B oil with dispersant increased from $2.1\%\;to\;7.2\%$ and from $1.0\%\;to\;4.4\%$, respectively. Accordingly, the dispersant belongs to the organic matter group of middle-biodegradability while mixtures in the mix ratio range of $1:10\~5:10$ belong to the organic matter group of low-biodegradability. The deoxygenation rate constant $(K_1)$ and ultimate biochemical oxygen demand $(L_0)$ obtained from the biodegradation experiment and Thomas slope method were found to be 0.125/day and 2.487 mg/l for dispersant (4 mg/l), respectively. $K_1\;and\;L_0$, were found to be $0.079\~0.131/day$ and $0.318\~2.052\;mg/l$ for a mixture of Bunker-A oil with dispersant and to be $0.106\~0.371/day$ and $0.262\~1.106\;mg/l$ for a mixture of Bunker-B oil with dispersant, respectively, having $1:10\~5:10$ mix ratios of dispersant to Bunker-A oil and Bunker-B oil. The ultimate biochemical oxygen demands of the mixtures increased as the mix ratio of dispersant to Bunker-A, B oils changed from 1 : 10 to 5 : 10. This suggests that the more dispersants are applied to the sea for the cleanup of Bunker-A oil or Bunker-B oil, the more decreases the dissolved oxygen level in the seawater.