• Membrane Journal
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• v.31 no.4
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• pp.268-274
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• 2021

One of the chronic problems in the issue of global warming is the emission of greenhouse gases. Carbon dioxide (CO₂), which accounts for the highest proportion of various greenhouse gases, has been continuously researched by humans to separate it. From this point of view, a poly(vinyl alcohol) (PVA)-based copolymer with acrylic acid monomer was utilized in a gas separation membrane in this study. We employed a free radical polymerization to fabricate PVA-g-PAA (VAA) graft copolymer. It was utilized in the form of a composite membrane on a polysulfone substrate. The proper amount of acrylic acid reduced the crystallinity of PVA and increased CO₂ solubility in separation membranes. In this perspective, we suggest the novel approach in CO₂ separation membrane area by grafting and solution-diffusion.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.429-437
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• 2018

The process gas piping of the offshore plant can cause a massive explosion if the gas leakage occurs during operation. For the purpose of precaution of gas leakage accident, an air pressure test is performed on the process equipment tests using a test pump as much as the power to the piping inner side, mix 99% nitrogen gas and 1% helium gas. The purpose of the air pressure test is to check the work conformity process by handling and regulation for initial piping process, assembly, installation of module, welding, center alignment of the pipes assembling flange gasket in an unrestrained free state. In this paper, the regulation of the problematic air pressure test was analyzed and the solution criteria were established. And leakage tests of existing equipment were performed applying these solution methods. As a result, it was confirmed that there was no problem.

• International Journal of Korean Welding Society
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• v.1 no.2
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• pp.30-35
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• 2001

Nowadays, repair welding on in-service natural gas pipeline is a matter of primary concern of gas company. The main purpose of this study is to investigate the effects of welding conditions on the allowable heat input for crack-free welds and welds without burn-through onto in-service natural gas pipeline. First of all, single pass weld bead on plates of the various thickness was deposited to evaluate the penetration of weld metal, the depth of heat affected zone and the hardness of repair weld under various welding conditions. Also, finite element analysis has been conducted to validate experimental results of bead-on plate welds and to develop appropriate model for repair welding. The welding experiments of bead-on-plate weld confirmed the influence of plate thickness, heat input and welding process on safety. And, the finite element model was demonstrated by comparing experimental results. The agreement between the computed and measured values was shown to be generally good. Therefore, It is possible to predict the safety of repair welding under various welding conditions with experimental results and finite element analysis model.

• Journal of Ginseng Research
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• v.9 no.2
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• pp.193-203
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• 1985

Lipid and fatty acid compositions of the free lipids in Panax ginseng (Korea, Japan and China), Panax quinquefolium (America, Canada) and Panax notoginseng (China) were studied by means of silicic acid column chromatography, thin-layer chromatography and gas-liquid chromatography. Free lipid contents were 1.13 to 1.24% in panax ginseng and 0.87 to 1.18% in Panax quinquefolium and 0.39% in panax notoginseng. Neutral lipid fractions were 81.2 to 84.4%, while glycolipid fractions 8.01% to 14.47% and phospholipid fractions 3.49 to 5.74% in free lipid contents. The major components were triglycerides, free sterols, diglyceride, free fatty acids and sterol esters in neutral lipid fractions, sterol glucoside, monogalactosyl diglyceride, digalactosyl diglyceride, esterified steryl glucoside in glycolipid fractions and phosphatidyl glycerol, phosphatide, ethanolamine, phosphatidyl choline in phospholipid fractions. The contents and compositions of neutral lipids and glyclipids were some different among various ginsengs, whereas phospholipids showed relatively similar compositions in the contents. Seventeen fatty acids were analyzed in the four free lipid fractions from the various ginsengs and the main fatty acids were linoleic acid, palmitic acid, oleic acid and linolenic acid. It was found that the amounts of some fatty acids were different among the various ginsengs, but the fatty acid patterns of these ginsengs were on the whole similar.

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.146-149
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• 1999

To develope the high speed gas cutting tip, consists of 3 pieces, supersonic axisymmetric jets issuing from various kinds of nozzles with a throat diameter of a few milimeters were experimentally investigated. The nozzle inlet pressure was varied from 4 to 8 kgf/$\textrm{cm}^2$. The parameters in nozzle design were throat diameter, throat length, taper angle, outlet diameter. The total pressure variation was measured by the pilot tube, 0.5mm outer diameter, along the center of the free stream jet. Also color Shilieren system was used to visualize the flowfield.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.196-200
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• 1989

Some s-triazine herbicides, namely simazine, atrazine, and propazine present as trace components in a complex mixture were analyzed by GC/MS and GC/MS/MS methods. Even though monitoring the molecular ions was the best in terms of sensitivity, adequate analysis could not be done when interfering species were present. When doubly charged ions which appeared at characteristic m/z values were monitored, chromatograms were rather free from interference. More importantly, selected reaction monitoring was found to provide a selective means of detection with general applicability.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.515-516
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• 2010

• 한국가스학회:학술대회논문집
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• 2001.10a
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• pp.285-290
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• 2001

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.9-10
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• 2006

A numerical method for simulating tree surface flows including the surface tension is presented. Numerical scheme is based an a fractional-step method with a finite volume formulation and the interface between liquid and gas is tracked by Volume of Fluid (VOF) method. Piecewise Linear Interface Calculation (PLIC) method is used to reconstruct the interface and the surface tension is considered using a Continuum Surface Force (CSF) model. Several free surface flow phenomena were simulated to show its effectiveness to find such phenomena.

• Natural Product Sciences
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• v.7 no.4
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• pp.110-113
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• 2001

The lipid classes constituents; hydrocarbons, wax esters, sterol esters, triacylglycerols, free fatty acids, 1,3-diacylglycerols, 1,2-diacylglycerols, free sterols, 2-monoacylglycerols, 1-monoacylglycerols, phosphatidylethanolamines, phosphatidylcholines, lysophosphatidylethanolamines and phosphatidylinositols of Nicotiana tabacum L. seeds oil were investigated by thin layer and gas chromatography. Palmitic, oleic and linoleic acids were the major components in all lipid classes studied.