• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.65-78
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• 2002

The suspension polymerization of styrene was carried out to obtain the narrow-size distribution of particle by using poly(vinyl alcohol) (PVA) as suspension stabilizer according to the degree of hydrolysis and the molecular weight. The stabilizing properties of suspension are also dependent on the interfacial tension of aqueous solution when PVA is added. When the polymerization process was carried out with low hydrolyzed PVA, it gave single, well-defined particles, while high hydrolyzed PVA gave clusters. The size of particle produced in this study ranged between 5${\mu}{\textrm}{m}$ and 10${\mu}{\textrm}{m}$. The suspending agent, PVA, influences on the drop size and drop stability, When the molecular weight of PVA is increased, the drop size decreases and the drops become more stable toward coalescence. An increase in the PVA concentration decreases the mean drop size and narrows the drop size distribution.

• Journal of Pharmaceutical Investigation
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• v.17 no.2
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• pp.89-93
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• 1987

Effects of Ssang Wha Tang (SWT), a blended Chinese traditional medicine, on the pharmacokinetics of sulfobromophthalein (BSP) were studied in the rats. BSP was administered via portal vein to the control and the SWT-treated rats. The in vitro distribution of BSP to blood cells and the hemato-physiological conditions, liver weight, GOT. GPT activity were also examined. The systemic clearance $(CL_s)$ of BSP was increased with the administration of SWT, but no significant differences were observed in the liver weight and in vitro distribution of BSP to blood cells. These results suggest that the intrinsic clearance of free BSP of the liver is increased with the administration of SWT in the rats.

• Nuclear Engineering and Technology
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• v.42 no.2
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• pp.175-182
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• 2010

As part of a fundamental study on the volume reduction of contaminated concrete wastes, the separation characteristics of the aggregates and the distribution of the radioactivity in the aggregates were investigated. Radioisotope $^{60}Co$ was artificially used as a model contaminant for non-radioactive crushed concrete waste. Volume reduction for radioactively contaminated dismantled concrete wastes was carried out using activated heavy weight concrete taken from the Korea Research Reactor 2 (KRR-2) and light weight concrete from the Uranium Conversion Plant (UCP). The results showed that most of the $^{60}Co$ nuclide was easily separated from the contaminated dismantled concrete waste and was concentrated mainly in the porous fine cement paste. The heating temperature was found to be one of the effective parameters in the removal of the radionuclide from concrete waste. The volume reduction rate achieved was above 80% for the KRR-2 concrete wastes and above 75% for the UCP concrete wastes by thermal and mechanical treatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.37-42
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• 2004

ECF and TCF bleaching methods are favored in bleaching plants over the world due to the increasing environment constraints. However, interaction of main stages(D and O stage) in ECF bleaching have not been understood completely yet. The degradation of holocellulose as a carbohydrate model compound was investigated by SEC(size exclusive chromatography) to estimate the change of its molecular weight distribution after O and D stage combination treatment. The molecular weight distribution of holocellulose was observed in two divisions(higher and lower molecular portions). It was also shown that DO sequence was more effective than OD, and DOD or ODO was more effective than DO. D stage had a little effect on the degradation of holocellulose, while the degradation of holocellulose increased as the time of the first O stage increased.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.37-44
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• 1998

The objective of this study is development of high strength lightweight concrete and application or structural use. For this, mix proportions for each strength level were selected from lab tests, and adapted to producing ready-mixed concrete in batcher plant. It was very important to prewet the lightweight aggregates sufficiently for producibility and also workability. Splitting tensile strength of high-strength lightweight concrete produced has lower values than that of normal weight concrete, but modulus of rupture and modulus of elasticity are not less than normal weight concrete. The strength reduction factor ($\lambda$) for sand-lightweight concrete make higher than 0.85 present in structures using high-strength lightweight concrete. And it was showed that not parabola distribution but triangular distribution of stress in compression zone.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.955-958
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• 2006

The purpose of this study is to find ways of recycling a great amount of gypsum as by-product from the manufacture of phosphate fertilizer. For the purpose, this researcher investigated physical properties of light weight Porous material using waste gypsum and a foaming agent, Sodium n-dodecyl Sulfate to utilize it as a interior material of construction. To determine such properties, the study examined pore size distribution and pore rate in accordance with contents of Sodium n-dodecyl Sulfate added. Then expanded vermiculite as light-weight aggregate was also added, when pore size distribution, pore rate and sound absorption rate were surveyed and measured.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.381-384
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• 2004

The goal of this study is to generate a landslide susceptibility map using GIS(geographic information system) based method. A simple and efficient algorithm is proposed to generate a landslide susceptibility map from DEM(digital elevation model) and existing maps. The categories of controlling factors for landslides, aspect of slope, soil, topographical index, landuse, vegetation are defined, because those factors are said to have relevance to landslide and are easy to obtain theirs sources. The weight value for landslide susceptibility is calculated from the density of the area of landslide blocks in each class. Finally, a map of susceptibility zones is produced using the weight value of all controlling factors, and then each susceptibility zone is evaluated by comparing with the distribution of each controlling factor class.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2723-2740
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• 2017

Steganographic schemes which are based on minimizing an additive distortion function defined the overall impacts after embedding as the sum of embedding costs for individual image element. However, mutual impacts during embedding are often ignored. In this paper, an adaptive JPEG steganographic method based on weight distribution for embedding costs is proposed. The method takes mutual impacts during embedding in consideration. Firstly, an analysis is made about the factors that affect embedding fluctuations among JPEG coefficients. Then the Distortion Update Strategy (DUS) of updating the distortion costs is proposed, enabling to dynamically update the embedding costs group by group. At last, a kind of adaptive JPEG steganographic algorithm is designed combining with the update strategy and well-known additive distortion function. The experimental result illustrates that the proposed algorithm gains a superior performance in the fight against the current state-of-the-art steganalyzers with high-dimensional features.

• Structural Engineering and Mechanics
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• v.55 no.4
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• pp.885-900
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• 2015

This paper introduces Romberg-Richardson's method as one of the numerical integration tools for computation of stress intensity factor in a pre-cracked specimen subjected to a complex stress field across the crack faces. Also, the computation of stress intensity factor for various stress fields using existing three methods: average stress over interval method, piecewise linear stress method, piecewise quadratic method are modified by using Richardson extrapolation method. The direct integration method is used as reference for constant and linear stress distribution across the crack faces while Gauss-Chebyshev method is used as reference for nonlinear distribution of stress across the crack faces in order to obtain the stress intensity factor. It is found that modified methods (average stress over intervals-Richardson method, piecewise linear stress-Richardson method, piecewise quadratic-Richardson method) yield more accurate results after a few numbers of iterations than those obtained using these methods in their original form. Romberg-Richardson's method is proven to be more efficient and accurate than Gauss-Chebyshev method for complex stress field.

• Electrical & Electronic Materials
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• v.7 no.5
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• pp.425-429
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• 1994

In this paper, we study on the plasma polymerized styrene as a negative electron-beam resist. Plasma polymerized thin film was prepared using an interelectrode inductively coupled gas-flow type reactor. We show that polymerization parameters of thin film affect sensitivity and etching resistance of the resist. Molecular weight distribution of plasma polymerized styrene is 1.41-3.93, and deposition rates of that are 32-383[.angs./min] with discharge power. Swelling and etching resistance becomes . more improved with increasing discharge power during plasma polymerization. Etch rate by RIE is higher than that by plasma etching.