• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.139-144
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• 2022

This study reports a microfluidic approach to produce monodisperse hydrogel microparticles in a simple and highly efficient manner. Specifically, we produce double emulsion drops with a thin oil shell surrounding an aqueous prepolymer solution, which is solidified via UV-induced free radical polymerization. When they are dispersed in an aqueous solution, the oil shell is dewetted due to the absence of surfactants, resulting in production of highly uniform hydrogel microparticles (C.V.=1%). Results show that production of monodisperse hydrogel microparticles with controllable size and composition can be achieved with minimal use of oil unlike water-in-oil (w/o) single emulsion-based approach. Furthermore, in-depth study of flow patterns in microfluidic device using a phase diagram exhibits a crucial relationship among relative flow rates while providing windows of readily controllable parameters for reliable manufacturing of hydrogel microparticles.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.227-232
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• 2008

In this research, organic extracts from roots of platycodon grandiflorum was tested to see the possibility for cosmetic natural surfactant. Interfacial properties of extracts of Platycodon grandiflorum was checked for interfacial tension, forming force, dispersion force, emulsion force, emulsion activity, and emulsion stability. At 0.005 wt% concentration, the interfacial tension against the caster oil was 11.5 dyn/cm which was lower than that of Tween 40 and quillaja bark. Extracts of Platycodon grandiflorum showed excellent emulsification activity and stability for cosmetic oils such as olive oil, soybean oil, and canola oil. In patch test using 2-5% of the extract and glycerin, the extract showed mild skin irritation. From the experiment, the extracts of platycodon grandiflorum root showed good interfacial properties as a cosmetic agent with minor skin irritation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.2
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• pp.119-131
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• 2012

The W/O emulsion is widely used for cosmetics because of its water-proofing benefit and long-lasting moisturizing effect. However, because of low stability of the W/O emulsion, it is very important to control the concentration of electrolyte and emulsifying agent, and ratio of water phase. Among these factors, we focused on the effects of different structures of emulsifying agents on the change of stability. Emulsifying agents were sorted into polyglyceryl ester, silicone and sugar series. We also examined the emulsifyingability of emulsifier by changing the ratio of normal and silicon oil in the oil phase. Through these experimental results, we figured out the property of w/o emulsion depending on the types of emulsifiers, and observed the stability of emulsion considering the change of particles and viscosity over time.

• The Journal of Information Technology
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• v.8 no.4
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• pp.43-50
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• 2005

In this paper, we describe a study on the relationship between photographic emulsion manufacture and hardening test of color paper. The hardener was prepared by the reaction of cyanuric chloride with sodium hydroxide, disodium hydrogenphosphate-12-water and trisodium phosphate-12-water in the presence of water. The hardener used in this study is a 2,4-dichloro-6-hydroxy-1,3,5-triazine mono sodium salt. The hardening test of photographic emulsion was studied respectively at pH 5.5, 7, 8.5 and about increasing temperature. Novel hardener can be used in photo-graphic emulsion of color paper and showed very good hardening effect.

• Journal of the Korean Applied Science and Technology
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• v.24 no.2
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• pp.205-210
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• 2007

In this paper, we describe a study on the relationship between neutral emulsion manufacture and hardening test of films. The hardeners were prepared by condensation of equimolar amounts of trichlorotriazine with benzene- or naphthalene-based amino or oxy acids at 0 to $5^{\circ}C$ and at pH 7, and used as hardening agents for gelatin. The hardening test of neutral emulsion layers was studied at pH 7.0. For example I(R=ONa) had strong hardening properties, I substituted with an aminobenzosulfonate moiety $(R=NHC_6H_4-p-SO_3Me$ where Me = K, Na) was a much weaker gelatin hardener, and when substituted with amino- or oxynaphthalene derivative (II, III) did not harden gelatin at all. Compound with 2 dichlorotriazine groups as IV exhibited hardening properties. The hardener can be used in neutral emulsion layer of film and showed good hardening effect.

• The Journal of Information Technology
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• v.9 no.1
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• pp.1-7
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• 2006

In this paper, we describe a study on the relationship between photographic emulsion manufacture and hardening test of films. The hardeners were prepared by condensation of equimolar amounts of trichlorotriazine with benzene- or naphthalene-based amino or oxy acids at 0 to 5$^{\circ}C$ and at pH 7, and used as hardening agents for gelatin. The hardening test of photographic emulsion was studied at pH 5.5. For example I(R=ONa) had strong hardening properties, I substituted with an aminobenzosulfonate moiety (R=$NHC_6H_4-p-SO_3Me$ where Me = K, Na) was a much weaker gelatin hardener, and when substituted with amino- or oxynaphthalene derivative (II, III) did not harden gelatin at all. Compound with 2 dichlorotriazine groups as IV exhibited strong hardening properties. The hardener can be used in photographic emulsion of film and showed very good hardening effect.

• The Journal of Information Technology
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• v.8 no.3
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• pp.51-56
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• 2005

In this paper, we describe a study on the relationship between spectral sensitization and photographic characteristics of color paper. The photographic emulsion used in this study is a green-sensitizing emulsion. U.V maximum absorption peak value of 9-phenyl-5,5'-diphenyl-3,3'-bis(3-sulfopropyl)benzoxazolo carbocyanine triethyl ammonium salt was observed 507nm, and wedge spectrograms maximum peak value of color paper added dye to photographic emulsion was shown 553nm. As compared with the absorption peak of the dye in methanol solution, the sensitizing peaks of 9-phenyl-5,5'-diphenyl-3,3'-bis(3-sulfopropyl)benzoxazolo carbocyanine triethyl ammonium salt have red shifts of 46nm. The photographic characteristics of green-sensitizing emulsion were obtained contrast(2.6), speed(48-57), fog(0.08). Therefore, benzoxazolo carbocyanine dye is of industrial importance as green-sensitizing dye in the spectral sensitization of photographic emulsion.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.2
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• pp.201-210
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• 2018

In this study, we formulated oil-in-water emulsion composition for skin care products containing jadeite powder which is well known as far-infrared radiating material. Jadeite powder could sustain stable dispersion in aqueous solvents over a month and this helped mixing it high content in oil-in-water emulsion formulation. To identify the effect of jadeite as a far-infrared radiator materials relating to the skin surface temperature change, we applied emulsion formulation containing 2 weight percent jadeite powder onto facial skin surface and blank formulation together and analyzed surface temperature with thermo-vision. Our results showed that the temperature difference between jadeite powder formulation applied region and blank formulation reached to 1.5 ~ 2.0 degree Celsius. We also performed same test with nephrite powder and titanium dioxide powder but only jadeite powder containing formulation showed significant skin temperature change. To elucidate main cause of heat energy transfer, we tested heat radiation, energy dispersive spectrometer analysis and measured far infrared radiance emissivity, diffuse reflectance spectra and water evaporation rate. We found out jadeite powder could retard water evaporation effectively from the skin surface and resist temperature drop down. This is because of the innate chemical composition and surface structure of jadeite, which can bind with water molecules to form hydrogen bonds. It is concluded that we can develop novel skin care products for moisturizing and thermos with jadeite powder.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.20 no.1
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• pp.37-51
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• 1994

Empty cross-linked chitosan microcapsule was prepared by chemical cross-linking reaction using glutaraldehyde(GA). Chitosan bead was also prepared by coacervation method using sodium hydroxide. The technique involves the formation of a chitosan solution in the discontinuous phase of W/O emulsion. The factors influencing the emulsion stability have been examined to establish optimum conditions Chitosan microcapsules were useful for encapsulation of biological materials, and chitosan bead was useful to prepare the biologically active peptide-bound polysaccharide. As a model compound Gly-His-Lys, cell growth factor, was successfully coupled to chitosan bead.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.129-133
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• 1998

We have studied a relationship between the pattern of complex modulus change versus internal phase volume ratio and the rheological consistency of concentrated W/O emulsions with Magnesium Sulfate in the range 0.0 to 0.5 wt% and with different oil polarities, respectively. The rheological consistency with time of concentrated W/O emulsion was checked using Fudoh Rheometer and the coalescence of deformed water droplets was examined using polarized light microscope(LEICA DMRP). To find the pattern of complex modulus change of the concentrated emulsions versus internal phase volume ratio, the effect of varying water phase volume fraction from 0.78 up to 0.85 on viscoelastic measurements was investigated using rotational rheometer (HAAKE Rheostress RS 50). The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. And the pattern of complex modulus increase versus volume ratio has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion.