• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.484-495
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• 2020

This study is a mixed surfactant (MimicLipid-MSM1000) that forms the same structure as that of the stratum corneum, sucrose distearate, polyglyceryl-2 dioleate, fermented squalane, ergosterol, 10-hydroxystearic acid, mixture consisting of was synthesized. When using 2~5 wt% of this mixed surfactant, it was possible to make an artificial skin mimetic that forms a multi-layer lamellar structure of 5~30 layers. An emulsion was prepared using this mixed surfactant, and a multi-layered lamellar phase was formed and analyzed mechanically. The appearance of this surfactant was a light brown hard wax, the hydrophilic lipophilic balance (HLB) was 12.53, the critical parameter value was 0.987, and the acid value was 0.13. Stability according to pH change was also stable in acidic (3.8), neutral (7.2) and alkaline (10.8). The particle size of the liquid crystal was found to be the most stable maltese cross lamellar crystalline droplet at 5~25mm. The size of the emulsified particles according to the change in the speed of the homo agitator is 2500 rpm (17.9mm±2.6mm), 3500rpm (12.5mm±2.1mm), 4500rpm (6.2mm±1.8mm) particles were formed. Liquid crystal forming particles were observed through a polarization microscope, and the formation structure of the liquid crystal was precisely analyzed with a scanning electron microscope (cryo-SEM). As an application field, it is expected that it will be widely applicable to the development of various prescriptions, such as various skin care cosmetics, makeup care cosmetics, and scalp protection cosmetics, by using a skin-mimicking surfactant.

• Korean Journal of Food Science and Technology
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• v.18 no.5
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• pp.376-381
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• 1986

A hypothesis that Korean home-made fermented soybean products are brown-pigmented in large part by contaminated bacteria is proposed. Twenty six strains of bacteria forming brown pigments in the presence of L-tyrosine were isolated from home-made soybean paste. They were characterized and all were identified as strains of Bacillus subtilis. The isolates produced dark brown to brownish black pigmentation on yeast extract-peptone-glucose agar (YPGA) supplemented with 0.1% L-tyrosine in 72 hours but not on YPGA. They also caused different depress of lighter pigmentation on potato dextrose agar and nutrient agar. When an arbitrarily chosen pigmenting isolate was cultivated in a liquid medium supplemented with L-tyrosine, it began to produce pigments only after cell growth stopped. The tyrosinase enzyme was extracted and the enzyme activity was measured by using L-tyrosine and 3-hydroxytyrosine (L-dopa) as substrates. The crude enzyme preparation porduced pigments at rates of $2.1\;{\times}\;10^{-3}\;and\;5.0\;{\times}\;10^{-3}$ optical density units/min measured at 490㎚ for tyrosine and dopa, respectively. Possible content of L-tyrosine in a soybean paste formula was calculated.

• Journal of Ginseng Research
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• v.44 no.4
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• pp.611-618
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• 2020

Background: It is well recognized that gut microbiota is involved in the biotransformation of ginsenosides by converting the polar ginsenosides to nonpolar bioactive ginsenosides. However, the roles of the gut microbiota on the pharmacokinetics of ginsenosides in humans have not yet been fully elucidated. Methods: Red ginseng (RG) or fermented red ginseng was orally administered to 34 healthy Korean volunteers, and the serum concentrations of the ginsenosides were determined using liquid chromatography-tandem mass spectrometry. In addition, the fecal ginsenoside Rd- and compound K (CK)eforming activities were measured. Then, the correlations between the pharmacokinetic profiles of the ginsenosides and the fecal ginsenoside-metabolizing activities were investigated. Results: For the RG group, the area under the serum concentratione-time curve values of ginsenosides Rd, F2, Rg3, and CK were 8.20 ± 11.95 ng·h/mL, 4.54 ± 3.70 ng·h/mL, 36.40 ± 19.68 ng·h/mL, and 40.30 ± 29.83 ng·h/mL, respectively. For the fermented red ginseng group, the the area under curve from zero to infinity (AUC_∞) values of ginsenosides Rd, F2, Rg3, and CK were 187.90 ± 95.87 ng·h/mL, 30.24 ± 41.87 ng·h/mL, 28.68 ± 14.27 ng·h/mL, and 137.01 ± 96.16 ng·h/mL, respectively. The fecal CK-forming activities of the healthy volunteers were generally proportional to their ginsenoside Rd-eforming activities. The area under the serum concentration-time curve value of CK exhibited an obvious positive correlation (r = 0.566, p < 0.01) with the fecal CK-forming activity. Conclusion: The gut microbiota may play an important role in the bioavailability of the nonpolar RG ginsenosides by affecting the biotransformation of the ginsenosides.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.266-273
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• 2011

Foamed glass was fabricated by using glass powder and foaming agents. For the glass powder, we used sodalime glass which's manufactured by using refused coal ore obtained as by-product from Dogye coal mine in Samcheok. And for the foaming agents, we used Calcium carbonate, Calcium phosphate and powder of shale type refused coal ore itself which has high content of carbon materials. We additionally used liquid binder for forming, and mixed together. And we formed rectangular shape and treated $800^{\circ}C$ for 20 min in an electrical furnace. The various kinds of foam glass samples were fabricated according to the kinds of foaming agents. The physical properties of samples, as specific gravity and compressive strength, were measured. Pore structure of each samples were investigated too. Foam glass with specific gravity of 0.4~0.7 and compressive strength of 30~72 kg/$cm^2$. Especially we get satisfying foam glass sample with low specific gravity of 0.47 and high compressive strength of 72 kg/$cm^2$ by the use of liquid calcium phosphate as foaming agent. It also had small and even shape of pore structure. Therefore, it is concluded that refused coal ore can be used for raw materials to manufacture secondary glass products such as a foamed glass panel for construction and industrial materials.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.575-580
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• 2010

The microstructure and positive temperature coefficient of resistivity (PTCR) characteristics of 0.1 mol%$Na_2Ti_6O_{13}$ doped $0.94BaTiO_3-0.06(Bi_{0.5}Na_{0.5})TiO_3$ (BBNT-NT001) ceramics sintered at various temperatures from $1200^{\circ}C$ to $1350^{\circ}C$ were investigated in order to develop eco-friendly PTCR thermistors with a high Curie temperature ($T_C$). Resulting thermistors showed a perovskite structure with a tetragonal symmetry. When sintered at $1200^{\circ}C$, the specimen had a uniform microstructure with small grains. However, abnormally grown grains started to appear at $1250^{\circ}C$ and a homogeneous microstructure with large grains was exhibited when the sintering temperature reached $1325^{\circ}C$. When the temperature exceeded $1325^{\circ}C$, the grain growth was inhibited due to the numerous nucleation sites generated at the extremely high temperature. It is considered that $Na_2Ti_6O_{13}$ is responsible for the grain growth of the $0.94BaTiO_3-0.06(Bi_{0.5}Na_{0.5})TiO_3$) ceramics by forming a liquid phase during the sintering at around $1300^{\circ}C$. The grain growth of the BBNT-NT001 ceramics was significantly correlated with a decrease of resistivity. All the specimens were observed to have PTCR characteristics except for the sample sintered at $1200^{\circ}C$. The BBNT-NT001 ceramics had significantly decreased $\tilde{n}_{rt}$ and increased resistivity jump with increasing sintering temperature at from $1200^{\circ}C$ to $1325^{\circ}C$. Especially, the BBNT-NT001 ceramics sintered at $1325^{\circ}C$ exhibited superior PTCR characteristics of low resistivity at room temperature ($122\;{\Omega}{\cdot}cm$), high resistivity jump ($1.28{\times}10^4$), high resistivity temperature factor (20.4%/$^{\circ}C$), and a high Tc of $157.9^{\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.85-92
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• 2010

$SF_6$ gas has been widely used in many industrial fields as insulating, cleaning and covering gases due to its outstanding arc-extinguishing and insulating properties. However, global warming potential of $SF_6$ gas is 23,900 times more than that of $CO_2$ and it remains in the air during 3,200 years. For these reason, technological and economical effects could be expected for the separation of $SF_6$ from gas mixtures by hydrate forming process. In this study, we carried out morphological studies for the $SF_6$ hydrate crystal to understand its formation and growth mechanisms. $SF_6$ hydrate film was initially formed at the interfacial boundary between gas and liquid regions, and then subsequent dendrite crystals growth was observed. The dendrite crystals grew to the direction of gas region probably due to the guest gas concentration gradient. The detailed growth characteristics of $SF_6$ hydrate crystals such as nucleation, migration, growth and interference were discussed in this study.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.808-815
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• 2008

The composites were fabricated 61[vol.%] ${\beta}$-SiC and 39[vol.%] $TiB_2$ powders with the liquid forming additives of 8, 12, 16[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid by pressureless annealing at 1650[$^{\circ}C$] for 4 hours. The present study investigated the influence of the content of $Al_2O_3+Y_2O_3$ sintering additives on the microstructure, mechanical and electrical properties of the pressureless annealed SiC-$TiB_2$ electroconductive ceramic composites. Reactions between SiC and transition metal $TiB_2$ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-$TiB_2$ electroconductive ceramic composites. Phase analysis of SiC-$TiB_2$ composites by XRD revealed mostly of ${\alpha}$-SiC(6H), ${\beta}$-SiC(3C), $TiB_2$, and In Situ YAG($Al_2Y_3O_{12}$). The relative density of SiC-$TiB_2$ composites was lowered due to gaseous products of the result of reaction between SiC and $Al_2O_3+Y_2O_3$. There is another reason which pressureless annealed temperature 1650[$^{\circ}C$] is lower $300{\sim}450[^{\circ}C]$ than applied pressure sintering temperature $1950{\sim}2100[^{\circ}C]$. The relative density, the flexural strength, the Young's modulus and the Vicker's hardness showed the highest value of 82.29[%], 189.5[Mpa], 54.60[Gpa] and 2.84[Gpa] for SiC-$TiB_2$ composites added with 16[wt%] $Al_2O_3+Y_2O_3$ additives at room temperature. Abnormal grain growth takes place during phase transformation from ${\beta}$-SiC into ${\alpha}$-SiC was correlated with In Situ YAG phase by reaction between $Al_2O_3$ and $Y_2O_3$ additive during sintering. The electrical resistivity showed the lowest value of 0.0117[${\Omega}{\cdot}cm$] for 16[wt%] $Al_2O_3+Y_2O_3$ additives at 25[$^{\circ}C$]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from $25^{\circ}C$ to 700[$^{\circ}C$]. The resistance temperature coefficient of composite showed the lowest value of $-2.3{\times}10^{-3}[^{\circ}C]^{-1}$ for 16[wt%] additives in the temperature ranges from 25[$^{\circ}C$] to 100[$^{\circ}C$].

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1159-1170
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• 2020

In this study, to improve the stability of fermented squalene developed using microorganisms, Microsome-SQ20 was prepared, and its physical behavior, properties, and efficacy were studied. The appearance of Microsome-SQ20 was a transparent liquid, no smell, and had a specific smell. The color was a transparent liquid, and the specific gravity was 0.928 and the pH was 5.82 (20% solution), forming a nano-emulsion suitable for use in cosmetics. It was confirmed that the content of the main component of squalene was 20.05%, which was stably sealed. The particle size measured by 0.1% aqueous solution of Microsome-SQ20 was 134.8 nm to obtain a bluish emulsified phase. The antioxidant effects of F-SQ and MF-SQ by DPPH radicals were 80.72% and 81.5%, respectively, showing superior effects compared to L-ascorbic acid. The cell viability of squalene (SQ), fermented squalene (F-SQ) and microsome squalene (MF-SQ) was at 10 ppm, respectively, showing 121.2%, 150.3%, and 129.9% cell viability. It was found that SQ, F-SQ, and MF-SQ had an elastase inhibitory ability of 8.7%, 10.33% and 8.7% at 10 ppm, respectively. In addition, the inhibitory ability of MMP-1 was 1.55%, 41.44%, 31.79% at 10 ppm for SQ, F-SQ, and MF-SQ, respectively, indicating that F-SQ significantly reduced the MMP-1 expression.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.2
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• pp.125-131
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• 2009

An electrolytic system (zinc anode-gallium cathode) was setup to evaluate the performance of several stirrers prepared for this study, where stirrers have been used to prevent uranium from forming dendrite on the cathode in pyrochemical process. In the case of no-stirring condition, zinc dendrites began to grow on the gallium surface in 1 hour and some dendrite grew out of the cathode crucible around 6 hours. When a rectangular stirrer or a tilt stirrer was rotated, at 40${\sim}$150 rpm, to mix the liquid gallium cathode, dendritic growth of zinc metal was prevented irrespective of revolution speed, but some of the deposits overflowed out of the cathode crucible owing to the large centrifugal forces at 150 rpm. The harrow stirrer did not nearly retard the dendrite growth at 40 rpm, but the dendrite growth was retarded at higher than 100 rpm and the zinc deposits also did not overflow at 150 rpm. Pounder could also prevent the dendrite growth to some extent but it had some difficulties in operation compared with other types of stirrers.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.53-53
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• 2019

Cypripediums, popularly called lady's slippers or moccasin flowers, are the showiest and most sought after hardy terrestrial orchids, collected and grown by orchid and alpine plant enthusiasts alike. In Korea, 4 species of cypripedium are reported as Cypripedium japonicum, C. macranthos, C. guttatum, and C. calceolus. We had already reported the feasibilities of C. macranthos and C. guttatum with in vitro germination methods from immature seeds. The seeds of white lady's slipper orchid (Cypripedium macranthos Sw. alba) were collected 65 days after pollination in 2018. The green pods were sterilized with flame and sowed immediately on the POM(Phytomax orchid maintenance media(R), Sigma) supplemented with BAP 0, 0.5, 1.0 mg/L and NAA 0, 1, 2mg/L. The germination of seed was observed 90 days after sowing, and the plantlets were subcultured to the same media according to the size of the protocorm with 1~2, 2~3, 3~4, 5~6, 7~8mm. The time of the subculture to the new media seems to be critical factors of forming rhizoids which is the hairy root of the cypripediums. As a results, the protorms of the white lady's slipper orchid was successfully germinated in the POM media supplemented BAP 0.5 and NAA 1.0 mg/L. The roots and rhizoids were formed in 5~6mm protocorms subculture over 95% survival ratio. We also tried to subculture to liquid medium without activated charcoal, however the browning or malformation of the roots was observed in the root. The formation of shoots from the protocorm was effectively enhanced in the POM media with non-additives of plant growth regulators. These results indicate the possibility of high and stable production and practical industrialization of endangered white lady's slipper orchids.