• Journal of the Korean Applied Science and Technology
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• v.13 no.1
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• pp.47-54
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• 1996

Cinnamoyl ester(PGEFC) of poly(phloroglucinol-formaldehyde) glycidyl ether which has photosensitive functional group was prepared to apply to photoresist. Photosensitivity of PGEFC was estimated by the solubility difference in organic solvent before and after exposure to light. The yield of residual film was calculated by immersing the sample-coated quartz plates in the solvent which was used in coating. The yield of the residual film which was closely related to the sensitivity of the film, was affected by the degree of polymerization of the backbone resin, sensitizers and their concentration. The sensitivity was depended upon the degree of polymerization. Most of effective sensitizer for PGEFC among the sensitizers was 2, 6-dichloro-4-nitroaniline.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.04a
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• pp.177-177
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• 2008

• Polymer(Korea)
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• v.36 no.1
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• pp.65-70
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• 2012

Glycidyl methacrylate (GMA) was used to introduce epoxy groups on the surface of polypropylene (PP) plate, used as a substrate, through plasma-induced graft copolymerization. Emulsion polymerization was applied for graft copolymerization of GMA and was compared with conventional solution polymerization to confirm its effect. Plasma treatment conditions under one atmospheric pressure were fixed as follows; the RF power of 200 W, the treatment time of 30 sec, the Ar gas flow rate of 6 LPM, and the exposure time of treated PP samples in air of 5 min. For graft-copolymerization, GMA concentration, reaction temperature, and reaction time was optimized to maximize the grafting degree of GMA. The maximum grafting degree of GMA was obtained at the condition of 12%-GMA concentration, $90^{\circ}C$ reaction temperature, and 5 hr-reaction time. Analysis results supported that the emulsion polymerization was more effective than the solution polymerization for grafting more GMAs on the surface of PP plate under the same reaction conditions.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.310-318
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• 2014

Objectives: This study examined the influence of the resin thickness on the polymerization of silorane- and methacrylate-based composites. Materials and Methods: One silorane-based (Filtek P90, 3M ESPE) and two methacrylate-based (Filtek Z250 and Z350, 3M ESPE) composite resins were used. The number of photons were detected using a photodiode detector at the different thicknesses (thickness, 1, 2 and 3 mm) specimens. The microhardness of the top and bottom surfaces was measured (n = 15) using a Vickers hardness with 200 gf load and 15 sec dwell time conditions. The degree of conversion (DC) of the specimens was determined using Fourier transform infrared spectroscopy (FTIR). Scratched powder of each top and bottom surface of the specimen dissolved in ethanol for transmission FTIR spectroscopy. The refractive index was measured using a Abbe-type refractometer. To measure the polymerization shrinkage, a linometer was used. The results were analyzed using two-way ANOVA and Tukey's test at p < 0.05 level. Results: The silorane-based resin composite showed the lowest filler content and light attenuation among the specimens. P90 showed the highest values in the DC and the lowest microhardness at all depth. In the polymerization shrinkage, P90 showed a significantly lower shrinkage than the rest two resin products (p < 0.05). P90 showed a significantly lower refractive index than the remaining two resin products (p < 0.05). Conclusions: DC, microhardness, polymerization rate and refractive index linearly decreased as specimen thickness linearly increased. P90 showed much less polymerization shrinkage compared to other specimens. P90, even though achieved the highest DC, showed the lowest microhardness and refractive index.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.109-114
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• 2003

Antimicrobial activities of grape seed ethanol extract and its serial solvent fractions were investigated against various food poisoning microorganisms. The grape seed ethanol extract showed dose dependant antimicrobial activity against Bacillus subtilis ATCC 9372 or Staphylococcus aureus ATCC 6538, whereas had limited effect on Pseudomonas aeruginosa IFO 3080, Salmonella enteritidis IFO 3313 and Escherichia coli ATCC 25922. Ethylacetate and butanol fractions ameng the serial solvent fractions of grape seed ethanol extract contained the catechin at the levels of 35.7 mg/g and 20.2 mg/g, respectively. Nevertheless, the butanol fraction of grape seed ethanol extract showed intense antimicrobial activity compared with the ethylacetate fraction on all microorganisms tested. It was found that the butanol fraction was mainly composed of oligomeric or polymeric polyphenols such as condensed tannins by the fractionation on C l8 cartridge according to the difference in the degree of polymerization. Therefore, it seems that the antimicrobial activity of grape seed ethanol extract is related to the degree of polymerization of proanthocyanidin as well as the total content of flavan-3-ol composing the proanthocyanidin.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.205-212
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• 1988

The effect of physicochemical characteristics on the freezing point depression of garlic bulb was studied to examine the reasons of cryoprotectivity in garlic bulb stored at subzero temperature. The composition of fresh garlic was characterized by having high soluble solids($40^{\circ}$ Brix; 90% on dry basis), comparing with $10^{\circ}$ Brix in case of other fruits and vegetables. Soluble solids were composed of 70% sugars, 20% protein, and 10% insoluble solids(including 3% of ash, 3% of crude fiber, and 4% of fat). The main component of sugars in garlic was fructosan with 1-29 degree of polymerization(D.P) and the fructosan of 4-5 D.P was over 50% of total fructosan. Freezing point of garlic bulb, which is a parameter of cryoprotectivity, was depressed as the concentration of soluble solids increased, and as the D.P value decreased in the same concentration of soluble solids.

• Journal of Sericultural and Entomological Science
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• v.41 no.3
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• pp.185-195
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• 1999

This study was carried out to improve the skin care property of the polyester fabric by finishing with sericin. It was known that skin care function, anti-oxidation, anti-tyrosinase activity and anti-elastase activity can be achieved from sericin finish. But, the moisture regain of the finished fabric was measured simply, because the major cause of the discomfort from polyester fabric has been anounced to be wetness. The effects of various treatment conditions on the properties of the finished fabric were measured, and obtained results were as follows: 1. The moisture regain at 40$^{\circ}C$ 90% RH were increased with the sericin uptake increasing. while it was not significant for the effects on the moisture regain depending on the treatment conditions like the degree of polymerization and treatment concentration of the binder. The moisture release of the fabric having sericin uptake 1%, 2% was faster than non treated fabric. The change of the moisture regain of the finished fabric from 40$^{\circ}C$ 90% RH to room temperature was 4∼5 times higher than that of knitted cotton fabric. 2. The frictional static charge was decreased with the degree of polymerization of the binder increasing. While the sericin uptake and treatment concentration of the binder were not significant. 3. The whiteness value of the fabric was slightly decreased by finishing with sericin and binder. In that cases, W values of the finished fabrics were above 90 while that depending on the degree of polymerization of the binder was not significant. 4. The major cause of the yellowness of the finished fabric was proved to be catalyst. The yellowness of the finished fabric with sulfur containing catalyst was lower than that with amine group containing catalyst. 5. The effects of the treatment concentrations of the cross-linking agent, catalyst and drying time on the wash durability were not significant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.664-668
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• 1999

The extracting conditions of alginates from sea tangle were evaluated by measuring water vapor permeability (WVP) and tensile properties of alginate film to obtain basic data of making an edible and biodegradable film. The alginates were extracted with $1\%,\;3\%$ and $5\%$ sodium carbonate ($Na_2CO_3$) for 1, 3, 5 and 10 hours, and the alginate film was made with various plasticizers. The higher concentration of $Na_2CO_3$ solution showed the lower viscosity and polymerization degree of alginate and the film prepared with alginates having low viscosity showed the higher WVP. The extracting hours had little effect on the WVP and the elongation of alginate film, but the polymerization degree of alginates directly affected the tensile strength of the film. The addition of sorbitol and polyethylene glycol as a plasticizer lowered the WVPs and the elongation of alginate film.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.506-514
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• 1993

The purpose of this study was to evaluate the effect of porcelain laminate thickness on polymerization of resin cement. G-Cera resin bonding system(G-C int., Japan) was used in this study and Heliolux II (Vivadent, Austria) was used for polymerization of resin cement. The thickness of porcelain laminates used in this study were 0.5mm, 1.0mm and 1.5mm and the degree of polymerization of resin cement was measured by microhardness theater(Matsuzawa, Model MXT-70, Japan). The obtained results were as follows : 1. The surface hardness of resin cements increaing the thickness of poreclain laminate was decreased. 2. The surface hardness of resin cements increasing the curing time was decreased.

• 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.