• Journal of the Mineralogical Society of Korea
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• v.32 no.3
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• pp.151-162
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• 2019

Todorokite, a tunnel-structured manganese oxide, can contain cations within the relatively large nanopores created by the $3{\times}3$ Mn octahedra. Because todorokite is poorly crystalline and found as aggregates mixed with other phases of Mn oxides in nature, the coordination structure of cations in the nanopores is challenging to fully characterize in experiment. In the current article, we report the atomistic coordination structures of $Mg^{2+}$ ions in todorokite tunnel nanopores using the classical molecular dynamics (MD) simulations. In experiment, $Mg^{2+}$ is known to occupy the center of the nanopores. In our MD simulations, 60 % of $Mg^{2+}$ ions were located at the center of the nanopores; 40 % of the ions were found at the corners. All $Mg^{2+}$ located at the center formed the six-fold coordination with water molecules, just as the ion in bulk aqueous solution. $Mg^{2+}$ ions at the corners also formed the six-fold coordination with not only water molecules but also Mn octahedral surface oxygens. The mean squared displacements were calculated to examine the dynamic features of $Mg^{2+}$ ions in the one-dimensional (1D) nanopores. Our MD simulations indicate that the dynamic features of water molecules and the cations observed in bulk aqueous solution are lost in the 1D nanopores of todorokite.

• Journal of Service Research and Studies
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• v.6 no.3
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• pp.57-78
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• 2016

The purpose of this research is to study how service recovery activities influence customers' commodity churning in the media telecommunication industry(CATV industry). Put it differently, we tried to identify this change of commodity churning rates by the stages of service failures, by which we intend to emphasize the importance of service recoveries. Korean media telecommunication market has already been saturated; customers tend to move to bigger major companies with better customer care increasingly. As once customers gone never returns, CRM functions are being reinforced over the time. We were able to have the following results. First, turning rates, for those experienced service failure, who were dissatisfied with service recovery activities are 2~5 times (monthly average turning rates are 1.3%) higher than those satisfied. Secondly, active service recovery activities at the customer's service request after experiencing service failure lowered churning rates significantly. The most effective timing is service recovery activities pre-recovery stage. Thirdly, reward activities after service recovery activities at the immediate recovery stage is more effective than service recovery at the arranged recovery schedule and reward activities after customer's expressing churning intension. The implications of this study are that firms should engage in service recovery activities at the time of identifying service failures, prior to customer's expressing churning intention, which means relatively lower ROI for the service recovery activities than the times of customers' expressing churning intention.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.413-420
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• 2015

The skin is one of the largest organs in our body and participates in many of the human organism's physiological and pathological events. Skin function were known for self-maintenance and self-repair, mechanical and chemical stress protection, protection against UV and environmental pathogenic micro-organisms, production of vitamin D, and social and psychological function through the physical aspect. The aim of this study was to evaluate the variation of biophysical parameters and to find relation with skin biomarkers in different anatomical site and age in Korean women. About 70 healthy volunteers in age range 20 to 49 were participated in this test. Test areas were the forearms and the cheek. Investigation to determine biophysical parameters on human skin, was carried out using various non-invasive methods. For analysis to skin biomarkers, we studied to examine various biomarkers for the quantitative determination of cortisol, fibronectin, keratin-1, 10, and 11, involucrin, and keratin-6 in human face and forearm. And we measured to skin biophysical parameters for skin anatomical site and age difference with non-invasive methods. As results of measuring site, some parameters were have following significant difference, stratum corneum hydration, trans epidermal water loss and skin color (L and a value). As results of age difference, skin colors were had only significant difference with age. For cortisol, keratin-6, fibronectin, keratin-1, 10, 11 contents, there were no significant difference in age and site. However, involucrin level in the cheeks were the highest for age group 30 ~ 39 compared to other age groups. These results suggest that in individual skin condition may explain detailed skin state variation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.1
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• pp.27-34
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• 2015

Many applications of nanoparticles have been developed since 1970s. Surface plasmon resonance (SPR) effect can be generated at the surface of nanoparticles by illumination. SPR is the resonant oscillation of conduction electrons at the surface material stimulated by incident light. The collisions between excited electrons and metal atoms can cause the production of thermal energy (photothermal effect). Here, we presented the development of thermo-cosmetics using photothermal effect of gold nanoparticles. Gold nanoparticles (GNPs) were chosen for it's low toxicity. We also and investigated the cell biocompatibility and heating effectiveness for photothermal effect of GNPs. Synthesized GNPs were verified by UV-vis spectrophotometer, where GNP has a characteristic absorbance spectrum. Concentration of GNP was measured by atomic absorption analyzer. The cytotoxicity was confirmed by MTT assay and double staining assay. Photothermal effect of GNP was demonstrated by the thermal increasing properties depending on GNP concentration, which was taken by an IR-thermal camera with a xenon lamp as the light source. If the thermal effect of GNP is applied for thermo-cosmetics, it can supply heat to skin by converting solar energy into thermal energy. Thus, cosmetics containing GNPs can provide benefits to people in the cold region or winter season for maintaining skin temperature, which lead to a positive effect on skin health.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.1
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• pp.23-29
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• 2020

The skin is colonized by a large number of microorganisms with a stable composition of species. However, disease states of skin such as acne vulgaris, psoriasis, and atopic dermatitis have specific microbiome compositions that are different from those of healthy skin. The target modulation of the skin microbiome can be a potential treatment for these skin diseases. Quorum sensing (QS), a bacterial cell-cell communication system, can control the survival of bacteria and increase cell density. Also, QS affects the pathogenicity of bacteria such as biofilm formation and protease production. In this study, we confirmed anti-QS activity of Amorepacific patented ingredients, which are Lactobacillus ferment lysate (using Lactobacillus plantarum APsulloc 331261, KCCM 11179P) through bio-reporter bacterial strain Chromobacterium violaceum. The purple pigment production of C. violaceum controlled by QS was reduced 27.3% by adding 10 ㎍/mL of Lactobacillus ferment lysate (freeze dried). In addition, the Lactobacillus ferment lysate increased growth of Staphylococcus epidermidis 12% and decreased growth of Pseudomonas aeruginosa 38.5% and its biofilm formation 17.7% at a concentration of 10 ㎍/mL compared to the untreated control group. Moreover, S. epidermidis was co-cultured with the representative dermatological bacterium Staphylococcus aureus in the same genus, the growth of S. epidermidis was increased 134 % and the growth of S. aureus was decreased 13%. These results suggest that fermented lysate using Lactobacillus plantarum APsulloc 331261 may be useful as a cosmetic ingredient that can control the balance of skin microbiome.

• Journal of the Korean Magnetics Society
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• v.5 no.6
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• pp.928-936
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• 1995

In this research, the processing control of NiCuZn Ferrite has been developed. The mixing and the size reduction of raw materials have been proceeded. In order to produce NiCuZn Ferrite, highly concentrated slurry with fixed ratio and wet ball milling were used. First, the dispersion behavior of raw mixture at the region of pH4~pH11 has been studied. Using wet ball milling operation, the best conditions of mixing and size reduction have been determined. Further more, the most suitable conditions, such as, dispersant kind, dispersant amount, milling time, and slurry concentration have been studied. The poly acrylic ammonium salt (PAN) was chosen as a suitable dispersant to have effective dispersion in basic region. The slurry of raw mixture without dispersant, showed high viscosity and poor grindability. As 0.7 wt% of PAN was added, the concentrated slurry (up to 55 vol%) was possible, and showed well grindability. After 18 h ball milling of 30 vol% of mixture slurry with 0.7 wt% of PAN, the average particle size and specific surface area of raw mixture were $0.54\mu\textrm{m}$ and $12.92m^{2}/cc$, respectively. The ball milled raw mixture, calcined at $700^{\circ}C$ for 3h, was totally changed into NiCuZn Ferrite with spinel phase.

• Nuclear Engineering and Technology
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• v.26 no.4
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• pp.471-483
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• 1994

A sodium fire facility with a test chamber of 1.7㎥ volume was constructed and operated to carry out experiments of sodium fires such as pool, spray, and columnar fires which might take place in sodium-related facilities. The experimental results of pool fires showed that the increase of temperature and pressure in the test chamber was much smaller than that of spray and columnar fires even though their amount of sodium injection in the chamber was much larger compared to other types of fires. And it was found in pool fires that the temperatures of sodium pool and the gas temperature in the test chamber had been maintained much longer than other types of fires, and that the chamber pressure had come to vacuum due to depletion of the oxygen for a large amount of sodium injection in the chamber. The experimental results of spray fires showed that sprayed sodium of small particles instantly reacted with oxygen, and that its reaction heat increased gas temperature and pressure of the test chamber rapidly and decreased them shortly. And the maximum gas temperature and pressure of the test chamber in spray fires ore greatly changed according to the inlet sodium temperature in the test chamber. The characteristics of the columnar fires were almost similar to those of spray fires, but the maximum temperature and pressure of the test chamber were much smaller even for a large amount of sodium injection. And it was shown in spray and columnar fires that the temperatures at each measurement position in the test chamber were quite different due to the instantaneous sodium oxidation in comparision with pool fires. Finally, the graphex powder was proved to be a very effective extinguisher against sodium pool fires.

• Food Science and Preservation
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• v.16 no.4
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• pp.499-505
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• 2009

Quality changes in fresh-cut potatoes during storage at $4^{\circ}C$ after treatment with low-temperature blanching and antibrowning agents were studied. Fresh-cut potatoes were treated by dipping for 1.5 min in a browning inhibitor solution containing 0.5% (w/v) ascorbic acid, 0.5% (w/v) citric acid, 0.5% (w/v) sodium chloride, 0.1% (w/v) trehalose, and 0.005% (w/v) biotin, at $60^{\circ}C$, with subsequent cooling for 1.5 min and storage at $4^{\circ}C$. The browning properties of fresh-cut potatoes were examined by measurement of polyphenol oxidase (PPO) activity and total phenolic content. Changes in quality attributes over a 14-day period were assessed in terms of titratable acidity, pH, water-soluble solid level, and gas analysis at $4^{\circ}C$. During storage, PPO activity increased, with the lowest activity seen after about 7 days of storage. Treatment with antibrowning solution at $4^{\circ}C$ increased visual sensory attributes during storage. Low-temperature blanching in distilled water more effectively inhibited browning compared with exposure to browning inhibitor solution, as assessed after 7 days of storage. Fresh-cut potatoes respired aerobically after different treatments during storage at $4^{\circ}C$.

• Korean Journal of Plant Resources
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• v.20 no.5
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• pp.398-403
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• 2007

This study was carried out to enhance germination of the seed by different immersion temperatures(15, 20, 25, 30 and $35^{\circ}C$) and times(1, 6, 12, 18, 24, 36 and 48 hours) in Cryptomeria japonica that is a major plantation species in the southern Korea. Optimum germination temperature was between $20^{\circ}C$ and $25^{\circ}C$, and the lowest germination was observed at $35^{\circ}C$ Moisture absorption increased with increasing immersion time as a whole and was high at $30^{\circ}C$ and $35^{\circ}C$. Initial moisture absorption rate was highest at $30^{\circ}C$ whereas was lowest at $15^{\circ}C$ Moisture absorption rate constant was also high at $30^{\circ}C$ and $35^{\circ}C$, however, it was relatively low at $15^{\circ}C$ and $20^{\circ}C$ Germination was the highest when the seeds were immersed for 48 hours at $30^{\circ}C$. In mean germination time(MGT) the seeds immersed for 48 hours at $30^{\circ}C$ did not differ from non-treatment, while the others showed higher values than non-treatment. Consequently, germination could be enhanced and MGT was kept by optimum immersion temperature and time.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.365-374
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• 1999

To obtain informations on vertical movements of water and solute in rice paddy field during the growing season, soil water contents and bulk electrical conductivities (${\sigma}_a$) were monitored using Time Domain Reflectometry. Soil water contents with depth showed ${\varepsilon}$-shaped profiles constituting of partly saturated zones at top and bottom layers and unsaturated zones (20-100cm) between them. Analysis by fitting with a van Genuchten-type model showed that soil water contents at 60cm were affected by both water supplied from surface water and groundwater, but at 80cm mainly affected by groundwater. Water percolation at the rate of 2cm $day^{-1}$ rates were, but large fluctuation from 10 to 38cm $day^{-1}$ in C1 layer (60-90cm). Therefore, it can be said that any water or solute entering C1 layer is very rapidly transported to C2 layer, especially during the period of high groundwater table staying, and retarded to a relatively constant percolation rate in C2 layer. This can be manifested by the fact that rapid decrease and steady increase of electrical conductivities at 50 and 110cm depth respectively, were found around that period.