• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1024-1029
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• 1994

The characteristics of the nitrogen adsorption with natural zeolite produced in Kampo area according to the chemical treatment by HCl and/or NaOH or the exchanging metal ion were investigated in the pressure range of 100~760torr at $25^{\circ}C$. The amount of nitrogen adsorption was followed at increment in the order of NaOH treatment>nontreatment>HCl treatment. Adsorption amount on natural zeolite treated with 0.5N-HCl/NaOH was improved about 200%, whereas that on natural zeolite treated with 0.5N-NaOH/HCl was decreased. When metal ion of natural zeolite was exchanged with $Na^+$, $K^+$ and $Cs^+$, adsorption amount of nitrogen was decreased as the size of cation was increased. But metal ion of natural zeolite was exchanged with $Mg^{2+}$, $Ca^{2+}$ and $Ba^{2+}$, the amount of nitrogen adsorption was increased.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.113-121
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• 2005

In order to resolve a common numerical integration inaccuracy of meshfree methods, we introduce an improved natural clement method called Petrov-Galerkin natural element method(PG-NEM). While Laplace basis function is being taken for the trial shape function, the test shape function in the present method is differently defined such that its support becomes a union of Delaunay triangles. This approach eliminates the inconsistency of tile support of integrand function with the regular integration domain, and which preserves both simplicity and accuracy in the numerical integration. In this paper, the validity of the PG-NEM is verified through the representative benchmark problems in 2-d linear elasticity. For the comparison, we also analyze the problems using the conventional Bubnov-Galerkin natural element method(BG-NEM) and constant strain finite clement method(CS-FEM). From the patch test and assessment on convergence rate, we can confirm the superiority of the proposed meshfree method.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.2
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• pp.111-119
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• 2013

The concept of the natural frequency is useful for understanding the characters of oscillating systems. However, when a circular cylinder floating horizontally on the water surface is heaving, due to the hydrodynamic forces, the system is not governed by the equation like that of the harmonic one. In this paper, in order to shed some lights on the more correct use of the concept of the natural frequency, a problem of the heaving circular cylinder is analyzed in the frequency domain. Previously, it was thought that the theory of Ursell (1949) could not be used to get the added mass and wave-making damping for short waves, however, they were obtained by applying an accurate collocation method to the theory in this study. Using the so developed numerical method, we found the added mass and wave-making damping of the circular cylinder for the entire range of the frequency. Then, the MCFR(Modulus of Complex Frequency Response) was used to locate the frequency corresponding to the local maximum of MCFR and we define it as the natural frequency. Comparing our results with the previous investigation, we found that the pressure distribution on the cylinder gets close asymptotically to that of a cylinder in infinite fluid OR close to that of the cylinder, that the approximation of the natural frequency by Lee (2008) is different from our new value only by 0.64%, and that the approximation of the heaving system by an equivalent damped harmonic oscillation is not proper by the reason that is clearly shown from the comparison of the shape of the corresponding MCFRs.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.117-122
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• 2004

Exessive UV radiation causes a lot of problems in our skin. In order to find out the alternative UV absorber that can safely be used in cosmetics, we have screened various natural extracts in terms of their UV absorbing effect. Some natural extracts, which possess antioxidative activities, have also been found to retard the oxidation process in our experiment. Natural compound such as 7-hydroxycymopol, baicalein, etc. could be transformed into adjuvant UV absorber by chemical modification. In cosmetics, its chemical stability against UV radiation, exposure to oxygen and other factors could be improved by using the silicone or W/S type emulsion. The values of MED (minimal erythema dose) were improved to 0.10 ${\pm}$ 0.02∼0.11 ${\pm}$ 0.02 by adding this natural extract into the cosmetic formulations. In conclusion, the results of the present study show that natural extracts could be used as an adjuvant UV absorber, if they are stabilized.

• Fashion & Textile Research Journal
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• v.19 no.4
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• pp.515-522
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• 2017

The natural dyeing industry has been faced with increasing demands of constant needs for environmentally and body friendly clothing products among modern consumers. Natural dyeing has attracted attention as a next-generation technology in green textiles. Dyestuffs need to be diversified for technological development activation in order to meet the increasing demands for natural dyeing. This study extracted dyeing solutions from the leaves of the Rose of Sharon (the national flower of South Korea) and investigated its dyeing properties for the development of various natural dyestuffs. This study investigates the dyeability of silk fabrics with Rose of Sharon leaves extract. Optimal conditions for dyeing of silk fabrics with the extract of Rose of Sharon were $40^{\circ}C/80min$ and $90^{\circ}C/60min$ with 100% concentration. Looking at the results, it showed the best K/S value at pH3, Sn pre-mordanting and Fe post-mordanting. Color fastness to washing, dry cleaning, rubbing and perspiration was good at grade 4-5 or 4. However, light fastness was observed in grade 2. In aspect of functional property, it showed an excellent result of 90% deodorization rate. In addition, its proven functionalities (deodorant properties) will help to produce high value added environment-friendly products. Those findings demonstrate the possibilities of the Rose of Sharon as an environment-friendly dye.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.65-71
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• 2009

In this study, performance and economic analysis of natural gas/syngas fueled 100 MWth chemical-looping combustion (CLC) combined cycle plant were performed. Net efficiency of both cases was 53~54%, corresponding to previous research. We used Chemical Engineering Plant Cost Index and Guthrie method to evaluate plant cost. For syngas fueled CLC combined cycle plant, the plant cost was higher since lower heating value(LHV) of syngas was lower than that of natural gas and cost of electricity(COE) was also higher since the cost of syngas was higher than that of natural gas. By sensitivity analysis, it was shown that the cost of syngas should be less than 5.3 $/GJ in order to make COE lower than 5.8 ¢/kWh which was COE of natural gas fueled CLC combined cycle plant.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.117-120
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• 2015

The number of campers has been consistently growing thanks to the introduction of a five-day work week and the time increase for a leisure. Thus, many types of facilities for camping are constructed. For instance, there are gravel camp site, which is called crushed stone, and normal soil camp site in case of private camp sites. The amount of natural background radiation, measured from site to site, was analyzed. The value of soil camp site was lower than that of crushed stone camp site. And the amount of natural background radiation from normal camp site was also lower than that from the artificial shade made by tarp. Consequently, it is noted that normal soil camp site with the plenty of woods should be chosen for camping place in order to avoid natural background radiation.

• The Research Journal of the Costume Culture
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• v.18 no.5
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• pp.1003-1016
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• 2010

The purpose of this study is to reorganize any rusty image including natural modeling characteristic presented from the natural phenomenon to certain patterns in order to create the fashion design that are valued in the expansion of independently expressional area and modeling art. As a method for research, the author analyzed the concept and characteristic for rust with a base of theoretical background by the documental research and realistic consideration, analyzed its modeling characteristic through domestic and overseas pictures, and e-documents as data, inspected the modeling activities of various categories that various images were adapted related to rust, looked into the concept of Digital Textile Printing and its producing procedure as an expressional method, and analyzed the examples of modern dress and its ornament making use of Digital Textile Printing. The conclusions of this study are as below. First, the rust occurred due to the natural phenomenon is the bond with different material like metal, each unique modeling characteristic occurs and harmony of various patterns has abundant aesthetic value. Second, the author could endowed sensible characteristic and speciality with works and could produce creative fashion design that painting, abstractive pattern and harmony of unique sense of colors are significant by using the image of rust, Third, to emphasize natural feeling of rust, the author could develop creative design that simple silhouette and impressive pattern look significant by reorganizing and applying rust according to repetition, increment, rhythm, contract, emphasis and harmony. Fourth, Digital Textile Printing method is used to induce visual effect by the expression of feels of rust, and the author could express the natural patterns, delicate expression for the feels of a material and unique design of emotion.

• Korean Journal of Materials Research
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• v.25 no.6
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• pp.279-287
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• 2015

In order to prepare anode materials for high power lithium ion secondary batteries, carbon composites were fabricated with a mixture of petroleum pitch and coke (PC) and a mixture of petroleum pitch, coke, and natural graphite (PC-NG). Although natural graphite has a good reversible capacity, it has disadvaantages of a sharp decrease in capacity during high rate charging and potential plateaus. This may cause difficulties in perceiving the capacity variations as a function of electrical potential. The coke anodes have advantages without potential plateaus and a high rate capability, but they have a low reversible capacity. With PC anode composites, the petroleum pitch/cokes mixture at 1:4 with heat treatment at $1000^{\circ}C$ (PC14-1000C) showed relatively high electrochemical properties. With PC-NG anode composites, the proper graphite contents were determined at 10~30 wt.%. The composites with a given content of natural graphite and remaining content of various petroleum pitch/cokes mixtures at 1:4~4:1 mass ratios were heated at $800{\sim}1200^{\circ}C$. By increasing the content of petroleum pitch, reversible capacity increased, but a high rate capability decreased. For a given composition of carbonaceous composite, the discharge rate capability improved but the reversible capacity decreased with an increase in heat treatment temperature. The carbonaceous composites fabricated with a mixture of 30 wt.% natural graphite and 70 wt.% petroleum pitch/cokes mixture at 1:4 mass ratio and heat treated at $1000^{\circ}C$ showed relatively high electrochemical properties, of which the reversible capacity, initial efficiency, discharge rate capability (retention of discharge capacity in 10 C/0.2 C), and charge capacity at 5 C were 330 mAh/g, 79 %, 80 %, and 60 mAh/g, respectively.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.480-485
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• 1996

Brain GABA transaminase is inactivated by preincubation with antidepressant/antipanic drug pheneizine (${\beta}$ethylphenylhydrazine) (mixing molar ratio 10:1) at pH 7.4. The reaction of enzyme with phenelzine was monitored by absorption and fluorescence spectroscopic methods. The inactive enzyme was fully reconstituted by addition of cofactor pyridoxal-5-phosphate. This result implies that the blocking of 1 mol of pyridoxal-5-phosphate per enzyme dimer is needed for inactivation of the enzyme. The time course of the reaction is significantly affected by the substrate .alpha.-ketoglutarate, which afforded complete protection against the loss of catalytic activity. The kinetic studies shows that phenelzine reacts with the cofactor of enzyme with a second-order rate constant of $2.1{\times}10^3M^{-1}s^{-1}$. It is postulated that the antidepressant/antipanic drug phenelzine is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degradative enzyme GABA transaminase.