• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.995-998
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• 1995

As the modern industrial processes become more complex, it is getting more difficult to model and control the processes. Naturally, an advanced type of DCS(Distributed Control System) with higher level functions is being sought Advanced DCS is a DCS with advanced functions such as fault diagnosis, GPC(Generalized Predictive Control), NN(Neural Network), and Fuzzy Control. In this thesis, we have studied a fuzzy control algorithm for realizing an advanced DCS. Its algorithm is implemented in a form of function code which is a process control language, being used by the industrial engineers. To verify the realized function code of the fuzzy control, the function code is applied to a continuous casting process of the Pohang Iron & Steel Works in Kwangyang. The rules of the fuzzy control were collected via interviews of the field operators and their operation documents. Finally, usability of the function code of the fuzzy control is shown via simulation for the continuous casting process model.

• Bulletin of the Korean Chemical Society
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• v.21 no.8
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• pp.817-822
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• 2000

Crack-free hard coating siIica films were prepared by sol-gel processfrom twokinds of silicon alkoxide (tetra-ethoxysilane and methyltrimethoxysilane) and two kinds of alcohol (methanol and isopropyl alcohol) with an acid catalyst,acetic acid. A silicate framework of the precursor solution was investigated by infrared spectros-copy (IR) in the process of hydrolysis and condensation. Theextent of the condensation in the intermediates was elucidated by gel permeation chromatography (GPC) and 29Si-NMR spectroscopy. The hard coating films werecharacterized by IR,scanning electron microscope (SEM), thermo gravimetric analyzer (TGA) and dif-ferential scanning calroimeter (DSC). The synthetic condition for the crack-free and transparent silica film for-mation was optimized interms of starting materials for the precursor solution as well as preparation method of the silica film.

• Biomedical Science Letters
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• v.25 no.2
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• pp.170-176
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• 2019

The objective of this study was to evaluate the characteristics of the mixtures of choline alphoscerate (alpha-glycerylphosphorylcholine, alpha-GPC), in the liquid form, and sucrose ester, which formed a solid composite. The choline alphoscerate solid composites were prepared using different ratios of sucrose ester, and different preparation methods, such as air drying and rotary evaporation, were compared for their preparation efficacy. We examined the characteristics of the solid composites by using scanning electron microscopy (SEM), angle of repose, and moisture content. The ideal mixing ratio of choline alphoscerate and sucrose ester was determined as 1:3 and air drying was found to be more suitable for the preparation of solid composites than rotary evaporation. SEM measurements of the degree of dispersion and the size of particles indicated that a high-temperature air method was more suitable. These results demonstrated the successful preparation of choline alphoscerate solid composites that have potential for industrial use.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.383-389
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• 2022

Natural(outdoor) and accelerated(artificial) weathering tests were performed to investigate their influence on polycarbonate. The polycarbonate materials were prepared of various formulations divided into three batches, with existing, development materials1, development materials2, containing mixture of UV additives. Weathering tests were carried out as outdoor weathering(Seosan, South Korea) and accelerated weathering(xenon-arc), and the results analysis were evaluated based on yellow-index(YI), scanning electron microscope(SEM/EDS), energy dispersive x-ray spectroscopy(XRD), and gel permeation chromatography(GPC). Among the three materials, processing method development materials1 with UV stabilizer was excellent in weathering. This study can provide basic data for standardization of development and performance evaluation on livestock barn roof.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.9-17
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• 2016

A purification method was established for high-purity chondroitin sulfate from skate cartilage. Hydrolytic extraction of skate backbone cartilage was investigated with the proteases alcalase and protamex, and the extraction contents of chondroitin sulfate were measured with several physicochemical processes. The yield of extract from skate cartilage with $40^{\circ}Brix$ concentration was 23.3% with 2% alcalase hydrolysis, which was decreased to 8.47% and 3.37% with the first and second additional ethanol purifications, respectively. The yield was 16.62% with one ethanol purification after hydrolysis with a mixture of 1% alcalase and 1% protamex. The content of chondroitin sulfate was measured as 39.88-45.08% with different ratios of ethanol solvent. The content was 42.92% at a solvent ratio of 1:1 with alcalase protease and 45.08% with a ratio of 1:2 using a protease mixture of alcalase and protamex. The molecular weight range of chondroitin sulfate was about 110-310 thousand Da, and the purity of chondroitin sulfate was 24.87-49.92% with a mixture of alcalase and protamex in GPC analysis. The maximum purity of chondroitin sulfate was 53.93% after ultrafiltration. The odor strength of chondroitin sulfate was decreased by 33% and 38% after ethanol purification and additional filtration with activated carbon, respectively. The odor concentration of ammonia and TMA from chondroitin sulfate was decreased by 52.1% and 37.89% with activated carbon filtration and two ethanol purifications, respectively, but it was necessary to eliminate the odor components efficiently using additional physicochemical processes.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.135-139
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• 1999

A new effective and economic method was developed, removing interferences such as chlorophyll and lipid from leaves with small amounts of reagents and solvents in order to analyse PAHs(Polycyclic Aromatic Hydrocarbons). The extract from a soxhlet containing $4{\sim}5g$ of leaves and 100ml of dichlormethane and refluxed for 20 hrs was concentrated and eluted with 60ml of a hexane:dichloromethane (1:1) mixture through a column of 9mm wide inner diameter and 130mm long, packed from the bottom with 2.5g of $Al_2O_3$, 1.5g of $SiO_2$and 2g of anhydrous $Na_2SO_4$. The eluent was concentrated and loaded on a GPC column of 20mm wide inner diameter and 280mm long, packed with 12g of Bio-beads. The column was washed with 37ml of the hexane:dichloromethane(1:1) mixture. Another 43ml of the mixture was eluted as a PAH fraction and collected. This eluent was concentrated under gentle nitrogen to $50{\mu}l$ and analysed using GC-MS. The recoveries, obtained by comparing with the amounts of the internal standards of deuterated PAHs were $43.3{\sim}107.5%$(RSD $2.2{\sim}9.5%$).

• Polymer(Korea)
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• v.38 no.4
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• pp.550-556
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• 2014

Recently, the peptide(or protein)-polymer hybrid materials (PPs) were sought in many research areas as potential building blocks for assembling nanostructures in selective solvents. In PPs, the facile routes of preparing well-defined peptide-polymer bio-conjugates and their specific activities in various applications are important issues. Our strategy to prepare the peptide-polymer hybrid materials was to combine atom transfer radical polymerization (ATRP) method with solid phase peptide synthesis. The standard solid phase peptide synthesis method was employed to prepare the PYGK (proline-tyrosine-glycine-lysine) peptide. PYGK is an analogue peptide, PFGK (proline-phenylalanine-glycine-lysine), which interacted with plasminogen in fibrinolysis. The peptide and the peptide-initiator were characterized with MALDI-TOF mass spectrometry and $^1H$ NMR spectrometer. The peptide-polymer, pSt-PYGK was characterized by GPC, IR, $^1H$ NMR spectrometer and TLC. Spherical micellar aggregates were determined by TEM and SEM. Current synthesis methodology suggested opportunities to create the well-defined peptide-polymer hybrid materials with specific binding activity.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.206-209
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• 2008

The modified supercritical water treatment method is adopted for hydrolysis of wood powder, Populus alba$\times$glandulosa. This modified method is containing 0.05% HCl or $HNO_3$ as acid catalyst. The supercritical water treatment(SCW) was performed for 1 min. with $350^{\circ}C$, $380^{\circ}C$, $400^{\circ}C$ and $425^{\circ}C$, respectively, under 230 $\pm$ 10 atm using continuous flow system. When acid was added to powder prepared for SCW treatment, the yields of monomeric sugars were significantly increased. The lignin remained after supercritical treatment was applied to gel permeation chromatography(GPC) for molecular weight distribution analysis. Compared to the lignin produced from SCW treatment without acid catalyst, the average molecular weight of lignin compounds treated with acid was clearly decreased. Particularly, Mn/Mw ratio is decreased. This result shows supercritical water treatment of wood powder can change the molecular weight of lignin to small size. However, it is necessary to be further studied for exactly characterizing the lignin produced from supercritical water treatment.

• Macromolecular Research
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• v.16 no.7
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• pp.614-619
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• 2008

Copolymers of phenyl alkyl acrylates/methacrylates are used clinically as soft materials for the foldable intraocular lens (IOL) to treat cataracts. In this study, copolymers of 2-phenylethyl acrylate (PEA) and 2-phenylethyl methacrylate (PEMA) of various compositions were prepared using free radical polymerization in solution. The composition of the copolymers was determined by $^1H$-NMR analysis. The reactivity ratios of the monomers were calculated using the conventional Fineman-Ross or Kelen-Tudos method. The reactivity ratio of PEA ($r_1$) and PEMA ($r_2$) were estimated to be 0.280 and 2.085 using the Kelen-Tudos method, respectively. These values suggest that PEMA is more reactive in copolymerization than PEA, and the copolymers will have a higher content of PEMA units. The glass transition temperature ($T_g$) of the copolymers increased with increasing PEMA content. The molecular weight and polydispersity indices ($M_w/M_n$) of the polymers were determined by GPC. Overall, these results are expected to be quite useful in applications to foldable soft IOL materials.

• Structural Engineering and Mechanics
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• v.75 no.6
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• pp.771-784
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• 2020

Reliability analysis techniques combining with various surrogate models have attracted increasing attention because of their accuracy and great efficiency. However, they primarily focus on the structures with continuous response, while very rare researches on the reliability analysis for structures with discontinuous response are carried out. Furthermore, existing adaptive reliability analysis methods based on importance sampling (IS) still have some intractable defects when dealing with small failure probability, and there is no related research on reliability analysis for structures involving discontinuous response and small failure probability. Therefore, this paper proposes a novel reliability analysis method called AGPC-IS for such structures, which combines adaptive Gaussian process classification (GPC) and adaptive-kernel-density-estimation-based IS. In AGPC-IS, an efficient adaptive strategy for design of experiments (DoE), taking into consideration the classification uncertainty, the sampling uniformity and the regional classification accuracy improvement, is developed with the purpose of improving the accuracy of Gaussian process classifier. The adaptive kernel density estimation is introduced for constructing the quasi-optimal density function of IS. In addition, a novel and more precise stopping criterion is also developed from the perspective of the stability of failure probability estimation. The efficiency, superiority and practicability of AGPC-IS are verified by three examples.