• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.25-32
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• 1998

The emulsion stability of W/O emulsion prepared by D phase emulsification during storage and handling is studied by using phase diagrams. The process of D phase emulsification begins with the formation of isotropic surfactant solution, followed by formation of oil-in-surfactant (O/D) gel emulsion by dispersion of octamethylcyclotetrasiloxane(OMCS) in the surfactant solution. Polyols were essential components for this purpose. To understand the function of polyols, the solution behavior of nonionic surfactant/oil/water/polyol systems were investigated by the ternary phase diagrams of polyoxyethylene oleyl ether/OMCS/propylene glycol(PG) aqueous solutions. The addition of PG increased the solubility of oil in the isotropic surfactant phase. D phase emulsification method has been applied to a new type of cosmetics. By using this emulsification technique, O/W emulsion were formed without a need for adjust of HLB. Fine and stable W/O emulsions were prepared by D phase emulsion.

• Journal of Korean Society of Rural Planning
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• v.11 no.1 s.26
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• pp.45-53
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• 2005

This study aims to suggest a rural village development policy considering tourists' stay pattern and villages' resources which can be infrastructure for green-tourism. For this purpose, a relationship table between amenity resources and the stay pattern was developed as a guide line to combine a set of several facilities fer village renewal. The amenity resources system was classified into three sub-classes(social, industrial, and natural/cultural/historical resources) and a relationship diagram between three classes and tourists' behavior was also defined. The table and diagram were applied to make renewal plan for 40 rural villages of the study area, Bukmyun, Cheonan, Chungnam province, so that the development scheme for the villages was suggested reasonably by the new findings of this study.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2001.12a
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• pp.22-37
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• 2001

Melatonin is secreted during the hours of darkness and is thought to influence the circadian and seasonal timing of a variety of physiological processes. Serotonin N-acetyltransferase (AA-NAT) which is found to be expressed in pineal gland, retina, and various tissues, catalyses the conversion of serotonin to N-acetylserotonin and is known as the rate-limiting enzyme in the biosynthetic pathway of melatonin. The compounds that modulate the activity of AA-NAT can be used to treat serotonin-and melatonin-related diseases such as insomnia, depression and seasonal affective disorders (SAD). Several assay methods have been developed by which to measure AA-NAT activity. We have also developed a simple, rapid and sensitive AA-NAT assay method that takes advantage of differences in the organic solubilities between acetyl CoA and N-acetyltryptamine. We screened modulators of AA-NAT activity from the water extracts of the medicinal plants. We found MNP1005 which strongly inhibited the activity of AA-NAT ($IC_{50}$=2.2$\mu$M). Enzyme inhibitory kinetic studies revealed that MNP1005 exhibited a noncompetitive inhibition toward tryptamine. The antidepressant effect of MNP1005 was investigated on behavioral despair test so called forced swimming test (FST). MNP1005 significantly increased swimming behavior by reducing immobility with treatment of 10 mg/kg when compared to the vehicle-treated control group (P < 0.05). This suggests that MNP1005 possesses antidepressant activity. The influence of chronic MNP1005 treatment on the expression of brain-derived neurotrophic factor (BDNF) was examined by in situ hybridization and Northern blot. Chronic treatment of MNP1005 blocked the downregulation of BDNF mRNA in the frontal cortex and other cortex regions in response to restraint stress.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.449-453
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• 2015

Recently, surfaces with micro and nano structures are the focus of various research and engineering fields to enhance wetting characteristics of the surfaces. Hydrophilic surfaces with hierarchical structures are generally characterized by the interfacial behavior of water droplets. In this study, the interfacial behavior of water droplets is experimentally investigated considering the scale of structures. Using the dry etching and conventional lithography method, quantitative hierarchical structured surfaces are developed. The behavior of the liquid-vapor interface on the test sections is visualized using an automatic goniometer and a high-speed camera. On the basis of the visualized data, the interfacial behavior of water droplets is intensively investigated according to surface geometrical characteristics.

• Polymer(Korea)
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• v.35 no.2
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• pp.113-118
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• 2011

Solid dispersion is used to improve the solubility of water-insoluble drug. Release properties depend on the characteristics of polymer and the physicochemical properties of solid dispersion. In this study the solid dispersions of ibuprofen and cellulose acetate were prepared using spray-drying and rotary evaporation. The physicochemical properties of the solid dispersions were analyzed by SEM, XRD, DSC, and FTIR. The hydrophilicity of polymer was analyzed by measuring the contact angle of water. The results of DSC and XRD analysis demonstrated that the crystallinity of ibuprofen was changed by solid dispersion preparation. The results of contact angle showed that hydrophilicity was proportional to polymer content. Release profile showed that for solid dispersion. the release rate of ibuprofen decreased as polymer content increased in intestinal juice (pH 6.8). The dissolution rate of ibuprofen was improved with increasing polymer content in gastric juice (pH 1.2).

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.208-216
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• 1993

The territorial behavior of the naked goby, Gobiosoma bosci, was observed in 80-liter aquaria. Social behavior was observed for an extended time in daily observation periods. Individuals of G. bosci, regardless of size and sex, exhibited agonistic behavior. The aggresive behaviors of approaching, threatening, attacking, and fighting were recorded as agonistic behavior. All individuals are capable of changing their color and camouflaging themselves by matching the color of bottom. Especially, the resident and the intruder are of the same size, the fighting duration was prolonged and the variability of coloration was at its peak.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.827-833
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• 2016

Wire-woven Kagome is a kind of Periodic Cellular Metal, which is known to have high strength, stiffness for its weight, and potential for mass production. In this work, we developed a new structure that mimics ${\alpha}$-cristobalite. First, an ordinary wire-woven Kagome was fabricated using metallic wires, and the tetrahedral cells were then filled with metal balls and epoxy. The wire-woven Kagome was transformed to have a negative Poisson's ratio by carrying out a specified amount of initial deformation. The fabrication possibility and kinematic behavior were checked by using FEA simulation. Finally, the mechanical properties were measured using compressive tests.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.11-17
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• 2015

High-density polyethylene (HDPE) piping, which has recently been applied to safety class III piping in nuclear power plants, can be butt-joined through the thermal fusion process, which heats two fused surfaces and then subject to axial pressure. The thermal fusion process generates bead shapes on the butt fusion. The stress concentrations caused by the bead shapes may reduce the fatigue lifetime. Thus, investigating the effect of the thermal butt fusion beads on fatigue behavior is necessary. This study examined the fatigue behavior of thermal butt fusion via a tensile fatigue test under stress-controlled conditions using finite element elastic stress analysis. Based on the results, the presence of thermal butt fusion beads was confirmed to reduce the fatigue lifetime in the low-cycle fatigue region while having a negligible effect in the medium- and high-cycle fatigue regions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.235-241
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• 2014

As a fiber-optic cable is being unwound, it is protected by a tube that is designed to prevent unwinding problems such as tangling and unintentional cutting. In addition, a guide body is separated from the protective tube if a shear pin breaks when the maximum allowable load is exceeded. Therefore, it is important to analyze and predict the unwinding behavior of the protective tube, as well as the load on the shear pin, to enhance the likelihood of a successful operation when laying cables at extreme depths. In this study, the protective tube and the guide body are modeled with particles and are constrained with a constant-length constraint. The load on the shear pin was verified against experimental data, and the unwinding behavior was predicted from the load prediction results.

• Korean Journal of Environment and Ecology
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• v.8 no.2
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• pp.160-166
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• 1995

Visitors to Chuwangsan National Park were survayed from August 3 to 5 n 1994. During this time, 346 visitors were contacted. Of those individuals, 65% were males. 63% of respondents reported that they had gone as far as college. 48% were 20 years of age. 97% of the survey respondents had experience to visit other national parks. The largest percentage of respondents were reported that they visited Chuwangsan Nat'1 Park for enjoying natural landscape. In group type, 50% were traveling with their family and 36% with their friends. In activity characteristics, 51% were day-time visitors, and 18% mentioned carrying in their on food. Generally most respondents were very interested in the environmental problem in national parks. The majority of visitors perceived that the environment of Chuwangsan Nat'1 Park were good enough. In six types of normative violations, the major reasons of littering were unintentional violation and releaser-cue violation. Most respondents were not likely to intervene to stop other visitors' depreciative behavior (Bystander intervention behavior). In two dilemmas, the more likely the intention to obey a regulation the less likely the intention to disobey a regulation, and vice-versa.