• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.339-345
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• 2014

For enhancing productivity of glulam, high frequency (HF) curing technique was researched in this study. Heat energy is generated by electromagnetic energy dissipation when HF wave is applied to a dielectric material. Because both lamina and adhesives have dielectric property, internal heat generation would be occurred when HF wave is applied to glulam. Most room temperature setting adhesives such as phenol-resorcinol-formaldehyde (PRF) resin, which is popularly used for manufacturing glulam, can be cured more quickly as temperature of adhesives increases. In this study, dielectric properties of larch wood and PRF adhesives were experimentally evaluated, and the mechanism of HF heating, which induced the fast curing of glue layer in glulam, was theoretically analyzed. Result of our experiments showed relative loss factor of PRF resin, which leads temperature increase, was higher than that of larch wood. Also, it showed density and specific heat of PRF, which are resistance factors of temperature increase, were higher than those of wood. It was expected that the heat generation in PRF resin by HF heating would occur greater than in larch wood, because the ratio of relative loss factor to density and specific heat of PRF resin was greater than that of larch wood. Through theoretical approach with the experimental results, the relative strengths of ISM band HF electric fields to achieve a target heating rate were estimated.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.478-485
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• 2014

This study is to form the self assembly of cubic crystalline phase to penetrate into the skin epidermis. The various performance synthesized diglyceryl phytylacetate (DGPA) having hydroxyl group (-OH) and 4 methyl chains with phytyl group was carried out as an amphoteric lipid such as emulsifying power, self assembly. Emulsifying activity of DGPA was very stabilized on only 1% of small content, it could make a W/O emulsion containing high internal phase incorporated with water. Cubic liquid crystal structure with DGPA on three-phase diagram was formed, when mixed DGPA, dimethicone (2CS), and water. Through three-phase diagram forming the cubic liquid crystal area, hexagonal structure zone, and mixing water phase and hexagonal structure area, reversed micelle area were respectively certified. Its structure was proved by the SAXS (small angled x-ray scattering) analysis. As an application, formation of cubosome containing 10% of magnesium ascorbylphosphate and 5% of pyridoxine tris-hexyldecanoate was encapsulated. Occlusive effect of cubosome had above 1.7 times better than reversed micelle. From using poloxamer of dispersing agent, phase structure recovered from W/O emulsion to cubic liquid crystal phase when storage in $33^{\circ}C$ incubator. Therefore, our this study is expected to be as epidermal-dermal skin absorbers in skin care cosmetics and pharmaceuticals industries as raw materials to form a cubic crystal phase through a more in-depth research to DGPA having amphoteric lipid property.

• The Southeast Asian review
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• v.27 no.1
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• pp.131-161
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• 2017

The political dynamics of Malaysia in 2016 should be seen as a process of losing an political opportunity mainly due to the split in opposition parties. The opportunity for political development was triggered by the ruling party in crisis. The ongoing 1Malaysia Development Berhad (1MDB) scandal involving the Prime Minister Najib Razak would have provided a favorable condition for the transfer of power. The opposition parties have however failed to utilize the chance that has arisen since the general elections in 2008 and 2013 due to the chronic problem of disunity. It can be seen as distortions of political development referring to a phenomenon in which a chance for regime change formed by the crisis in authoritarian regime is distorted by internal conflicts among opposition parties. Malaysia's political turmoil seemed to paralyze its economy while foreign policy was used as a tool for domestic politics. It was reported that the key economic indicator have worsen including exports and budget deficit. The ringgit had dropped to its lowest level since the economic crisis in 1997-98 which was mainly attributed to diminishing credibility on the Najib's administration. Najib's political struggle has also impeded Malaysia's foreign policy which has attempt to embrace China and the Rohingya issue. The chance to manage key risks would be diminished if oppositions' disunity continues as there is speculation that the general election could be held in 2017.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.323-331
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• 2019

The purpose of this study was to identify the emotional and stress factors of the stroke victims living in the community and to investigate the effect of these factors on the level of social participation. Data collection collected data on the level of emotional awareness, stress, and social participation in welfare centers, public health centers, and stroke disabled people using community services. The level of social participation according to general characteristics was analyzed by descriptive statistics and one-way ANOVA. Emotional factors, stress factors, and social participation levels were analyzed by pearson correlation analysis and multiple regression analysis. As a result, there were no statistically significant factors in the sub-domains of emotional factors that affect social participation performance and satisfaction. In the sub-areas of stress factors, personal internal stress and interpersonal stress were statistically significant variables. The explanatory power showed social participation accomplishment was 34% and satisfaction was 33%. Therefore, various approaches should be made considering stressful factors to achieve rehabilitation into the local community, and additional research is needed to identify psychosocial variables that affect social participation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.841-847
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• 2018

Since global energy consumption and demand for energy have dramatically risen, a focus on environmental problems and sustainability has become more important. Clean and renewable energy sources such as offshore wind power generation have received attention among new renewable energy options as alternative energy resources. Due to maintenance and operational perspectives, offshore wind farms have been planned for installation in many coastal waters. However, development of offshore wind farms faces interference from existing maritime traffic along the planned areas. In order to safely and effectively govern marine traffic in the vicinity of wind farms and inner areas, standard criteria are suggested to allow vessels to sail the internal waters of offshore wind farm areas. Therefore, the purpose of this study is to establish allowable criteria for sailing vessels and safety zones for offshore wind farms by investigating the local regulations of various offshore wind farm cases overseas. The commended inner safety zone of wind farms is proposed to be a distance of 150 % of the rotation diameter of the wind turbine rotor and a distance of 200 m from the outer wind turbine for the outer safety zone. Besides this, the allowable criteria for sailing vessels within a wind farm is proposed to have an air draft of 14.47 m south-west wind farm sea areas for a minimum margin to avoid hull contact through evaluation of the tide and height of a wind turbine. further studies will be needed to establish vessel sailing criteria among adjacent offshore wind farms as well as vessel sailing criteria within a single offshore wind farm.

• The Journal of the Korea Contents Association
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• v.19 no.3
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• pp.500-509
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• 2019

The study looked at the effect of body food on stress reduction and NK cell activity in improving natural healing for nurses, and examined whether it is effective in preventing and curing human health. The study was conducted for 30 days on 22 nurses who currently worked for more than a year at a general hospital in Gyeonggi Province. Stress measurements were conducted through pulse wave measuring instrument, and blood tests were conducted on the activity of NK cells. Treatment of collected data was performed by Paired t-testing through the Stat program SPSS 21 and providing body food suitable for the physical quality of participants after the classification of the body based on the internal diameter of the emperor and scholarship. Studies have shown that the effect on reducing the stress of body food has significant positive effects and that body food is effective for the activity of NK cells. This study has the following significance: First, the main health threat factor for modern people is the increased resistance of natural healing through body food to stress, which has the potential to prevent disease. Second, immunodeficiency in disease prevention and treatment is very important, which can increase the natural healing power of the human body by increasing the activity of NK cells through body food.

• Journal of IKEEE
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• v.23 no.1
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• pp.193-199
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• 2019

In this study, we have proposed a floating metal guard ring structure based on TCAD simulation in order to enhance the breakdown voltage characteristics of gallium oxide ($Ga_2O_3$) vertical high voltage switching Schottky barrier diode. Unlike conventional guard ring structures, the floating metal guard rings do not require an ion implantation process. The locally enhanced high electric field at the anode corner was successfully suppressed by the metal guard rings, resulting in breakdown voltage enhancement. The number of guard rings and their width and spacing were varied for structural optimization during which the current-voltage characteristics and internal electric field and potential distributions were carefully investigated. For an n-type drift layer with a doping concentration of $5{\times}10^{16}cm^{-3}$ and a thickness of $5{\mu}m$, the optimum guard ring structure had 5 guard rings with an individual ring width of $1.5{\mu}m$ and a spacing of $0.2{\mu}m$ between rings. The breakdown voltage was increased from 940 V to 2000 V without degradation of on-resistance by employing the optimum guard ring structure. The proposed floating metal guard ring structure can improve the device performance without requiring an additional fabrication step.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.712-722
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• 2020

Purpose: The damage from earthquakes with a magnitude of 5.0 or greater Korea has increased in South Korea. When a earthquake occurs, internal facilities and electric equipment besides urban structures will be damaged. Thus, in this paper, an earthquake-induced seismic isolation device with double slip fiction surfaces which can reduce the damage of electric power equipment such as distribution panel and then the seismic performance was evaluated. Method: To evaluate the seismic performance shaking table test was performed, a seismic performance comparison was performed according to the presence or absence of a seismic isolation device. The attenuation effect of the seismic isolation device are analyzed by comparing response acceleration and displacement for different frequencies and acceleration levels. Result: As a result of the test, the acceleration amplification was up to 42% less than when the seismic isolation device was installed in comparison to the other case without the seismic device. This is believed that the amplification energy has reduced because the displacement between the double slip friction surfaces of the seismic device play a role in dissipating the seismic energy. Conclusion: The seismic device with double slip friction surfaces has a greater earthquake attenuation effect in strong earthquakes than in weak ones, so the greater the frequency, the better the earthquake attenuation effect. Therefore, it is judged that earthquake energy can be decreased by applying to electric equipment such as distribution panels.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.205-216
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• 2021

This study aims to discuss ways needed to prepare their careers through relations between the personal internal factors perceived by college students in the process of career preparation and the external factors they experience during college life. To this end, the study conducted not only a questionnaire survey of 927 students at K University in Seoul but also hierarchical multiple regression analysis, independent two sample t-test, and one-way ANOVA (analysis of variance). The study set career preparation as a dependent variable, presented research models in four steps, and the explanatory power of each model was statistically significant. According to the findings of the study, both Model 1 and Model 2, gender had a significant impact on career preparation. Also, when self-directedness was added to Model 2, self-directedness had a greater impact on career preparation than gender did. When satisfaction with extracurricular activities was added to Model 3, this factor turned out to be helpful for career preparation. When college immersion, or a sense of belonging to college, was added to Model 4, the higher the sense of belonging students perceived, the more helpful they felt it for their career preparations. This study is expected to be helpful in preparing a policy to support college students' career preparation by grasping the relations between the personal characteristics of college students and career-related activities and college immersion they experience during college life.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.5
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• pp.43-55
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• 2020

The effect of cutted pin in front of pin-fin array was analyzed for increasing the cooling performance of gas turbine blade. The numerical simulations were conducted to figure out the flow and thermal characteristics. The base case which is staggered pin-fin array, cut pin case 1 which has X₂/D_p=1.25 cut pin and cut pin case 2 which has X₃/D_p=1.75 cut pin were compared. The results showed that cut pin increases the strength of the horseshoe vortex which occurred at the leading edge of pin-fin array. Furthermore, the wake effect is reduced at the trailing edge of pin-fin array. As a result, the heat transfer distribution on the endwall increases. However, the friction factor increases owing to the installation of cut pin, but the thermal performance factor is increased maximum 23.8% in cut pin case 2. Therefore, installation of cut pin will be helpful for increasing the cooling performance of pin-fin array of gas turbine blade.