• Journal of the Korean Applied Science and Technology
• /
• v.36 no.2
• /
• pp.434-447
• /
• 2019

Polyethylene glycol (PEG) is widely used in cosmetics as a surfactant, detergent and emulsifier. During the manufacturing process, 1,4-dioxane, which is toxic to humans, can be produced as a by-product by dimerization of ethylene oxide. As consumers' interest in cosmetic ingredients has increased, the need for safe emulsion research without PEG ingredients in the personal care market has increased. With increasing consumer interest in cosmetic ingredients, the need for safer emulsion research without the PEG ingredient in the personal care market has increased. In this study, we aimed to develop and stabilize nanoemulsion formulation without PEG. Response Surface Methodology (RSM) was used to develop optimized nanoemulsion formulations. Surfactant content (2~4%), oil content (4~8%) and polyol content (12~24%) were set as independent variables as a result of preliminary experiments for determining independent variables and ranges. The particle size, zeta potential, turbidity, and polydispersity index of the formulation were measured as response variables. As a result of measurement of the prepared nanoemulsion by FIB (Focused ion beam), spherical particles were found to have a size distribution of 100 to 200 nm. The stability of each formulation was evaluated for 30 days at each temperature ($4^{\circ}C$, $25^{\circ}C$, and $45^{\circ}C$). The optimal formulation considering the optimum particle size, turbidity, polydispersity index and zeta potential was found to be surfactant (2%), oil (8%) and polyol (24%).

• Korean Journal of Culture and Social Issue
• /
• v.14 no.1_spc
• /
• pp.299-317
• /
• 2008

The school drop-out among the youth has grown to become a serious social problem since about 2000 and calls for an attention to its seriousness. Therefore, this study reviewed the statitistical reports and the previous empirical findings on the school drop-out and integrated to establish a comprehensive understanding of this social phenomenon. The main concepts and terminologies on school drop-out, the current statistics, the possible causal factors and the usual trajectory the youth take after dropping-out of school were discussed to conceptualize the issue. Analyses indicated 12 characteristics of the students who dropped out of school. Those 12 characteristics were restructured according to the ecological conceptual model. The social instability and the financial crisis in the 1990's has eroded the stability of the primary environments of adolescents such as family and school. The family breakdowns from divorce and other reasons weakened psychological and financial support for adolescents. The diminished authority of teachers and school over students exposed conflicts between teacher and students, students' loss of purpose and interest in academic attainment. The adolescents showed emotional reponses like increased level of depression, helplessness, aggression, indicated cognitive reponses such as the loss of purpose and interest in studying, a heightened sense of uncertainty of the future, and behavioral responses like sexual acting out behaviors, and bullying. The unmet psychological needs of adolescents result in run-away and school drop-out behaviors, which in turn progress into juvenile delinquency as the society fails to provide adequate and appropriate guidance and interventions. The intervention strategies at the national level were proposed and the limitations of the study were discussed.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.5
• /
• pp.119-124
• /
• 2023

This study analyzed the impact of the real estate changes on the unemployment rate in Korea. Using monthly data from January 2013 to February 2023, the study employed a multiple regression analysis model. The key findings are as follows: First, there was a significant causal relationship between the real estate changes and the unemployment rate. Specifically, an increase in the real estate market led to a significant decrease in the unemployment rate, while a decrease in the real estate market resulted in a significant increase in the unemployment rate. Second, an increase in the loan interest rate was found to significantly reduce the unemployment rate, while a rise in interest rates had positive effects on the employment. Furthermore, an increase in inflation was associated with a significant rise in the unemployment rate. Moreover, an increase in the number of permits issued for housing construction significantly reduced the unemployment rate. Lastly, conducting robustness tests by substituting variables did not significantly alter the analysis results, indicating the robustness of the impact of the real estate changes on the unemployment rate. Based on the above analysis, it can be inferred that the fluctuations in real estate prices in South Korea are linked to fluctuations in the unemployment rate, and stable management of the real estate market may contribute to the stability of the unemployment rate.

• Journal of the Korean Magnetics Society
• /
• v.26 no.2
• /
• pp.39-44
• /
• 2016

Determination of the structural, electronic, and magnetic properties of the magnetically doped bismuth-telluride alloys are drawing lots of interest in the fields of the thermoelectric application as well as the research on magnetic interaction and topological insulator. In this study, we performed the first-principles electronic structure calculations within the density functional theory for the Gd doped bismuth-tellurides in order to study its magnetic properties and magnetic phase stability. All-electron FLAPW (full-potential linearized augmented plane-wave) method is employed and the exchange correlation potentials of electrons are treated within the generalized gradient approximation. In order to describe the localized f-electrons of Gd properly, the Hubbard +U term and the spin-orbit coupling of the valence electrons are included in the second variational way. The results show that while the Gd bulk prefers a ferromagnetic phase, the total energy differences between the ferromagnetic and the antiferromagnetic phases of the Gd doped bismuth-telluride alloys are about ~1meV/Gd, indicating that the stable magnetic phase may be changed sensitively depending on the structural change such as defects or strains.

• Korean Business Review
• /
• v.21 no.1
• /
• pp.51-71
• /
• 2008

Career indecision has long been a phenomenon of interest to parents, faculty, school counselors, and others who advise young adults on their career choices. The earliest work on career indecision focused almost exclusively on the negative consequences that young adults faced as a result of lack of self-insight into their own skills and abilities, lack of specific information about various occupations and labor markets, and fear of commitment to any career path in particular. More recently, researchers have noted that some of the short run negative consequences of early career indecision may ultimately lead to long-term positive consequences, particularly if better person-occupation fit is achieved as a result of young adults' extended search behavior. Extroversion, agreeableness, emotional stability, and openness showed to have negative effects on indecisiveness. In case of lack of job information, only extroversion and emotional stability showed to have negative effects on indecisiveness, and openness showed negative effect. Indecisiveness has negative effect on preparatory job search behavior. Lack of information has negative effect on preparatory job search behavior and active job search behavior.

• Journal of Korean society of Dental Hygiene
• /
• v.8 no.2
• /
• pp.53-66
• /
• 2008

There was to purpose of this study improves analyzing cause that prosthesis brings bite engaging that is inaccurate in patient's mouth, when supposed that all conducts that do in operatory and dental laboratory are perfect. Impression did check bite by alginate impression material and polymerization style silicon impression material that use usually in presence at a sickbed Irreversibility, hydrocolloid, alginate impression material washed in flowing water and poured anhydrite after wait about 8 minutes so that region that charge interest after impression check bite may become undoing. And hydrophile property addition polymerization style impression material poured anhydrite after blow 30 considering impression material dwell time and H2 gas occurrence time (5~15 minute) after have washed in flowing water. I got each 7 models, result that manufactures total 28 and measures by third dimension measuring instrument (Meteo, Korea) following sequence curing in tray holder and floor 1, By Alginate impression when is hardened in tray holder and when is hardened in the floor after do check bite, SPH 4, SPH5 all as there is synonymy appeared(P<0.05). By in case do not use average 0.1741 in case use tray holder in 0.0447 SPH5s in case do not use average 0.2838 pastas in case use tray holder in SPH4 0.0309, When did not use both SPH4 and SPH5 tray holder, when used tray holder, 1 appeared more greatly. 2. By amity sex addition polymerization style silicon impression when is hardened in tray holder after do check bite and when is hardened in the floor SPH 4, a11 of the SPH5s very big synonymy be(P>0.05). And in case use tray holder in 0.000657 pasta SPH5s in case do not use average 0.000129 pastas in case use tray holder in SPH4 average 0.000114 pastas, by in case do not use 0.000757, I appeared more greatly when used tray when did not use both SPH4 and SPH5 tray holder, but 1 appeared is not level to keep in mind(Table 8~9). 3 SPH4 was looked very big mindfulness in model that manufacture doing impression check bite by Alginate and model that do impression check bite by amity sex accessory penalty silicon without using tray holder(P< 0.001). I use tray holder and SPH4 did not appear synonymy in model that manufacture doing impression check bite by Alginate and model that do impression check bite by amity sex accessory penalty silicon(P>0.05). Study finding of above when see synthesis Alginate certainly tray holder use must and I could know that hardening method does not exert big influence on volume stability if remove impression sieve of excess because amity sex accessory penalty silicon passes over tray, Also, Alginate impression material previewed can get heading a conspiracy style that volume stability of accessory penalty silicon impression material degree is if use tray holder.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.851-860
• /
• 2020

With an increase in the aging population and a rising social interest in health and welfare, studies to improve healthcare in the elderly are being actively conducted. This study attempted to improve the current design and manufacture of elevating electric wheelchairs to enhance user safety and convenience. Seat design based on the user's body shape, convenience while boarding or alighting, caster turning radius and, safety and stability features that prevent shaking when the user gets up or sits down were improved. A driving experiment was conducted to evaluate the operation of the indoor electric wheelchair designed and manufactured with these additional functionalities. During the test, the performance parameters evaluated were continuous driving time, turning radius, maximum lifting and lowering load, maximum lifting height, noise level, minimum distance sensing by the driving auxiliary sensor, ability to interact with server and app programs, and the duty cycle maximum error rate. The test confirmed that this improved electric wheelchair successfully met target parameters. In a future study, we will evaluate this improved electric wheelchair from a user's perspective for its usability parameters, such as satisfaction, convenience and stability.

• Journal of the Korean Geographical Society
• /
• v.51 no.1
• /
• pp.143-166
• /
• 2016

This study aims to consider spiritual therapeutic landscapes thought the case of catholic sacred places in Korea. The catholic sacred places, which have been a series of persecution, are distributed in 300 all over the country and can be divided into a formational type, a selective type, and a participatory type. In the formational type, the catholic sculptures are scattered here and there; but it seems that there are limits somewhat to feel the emotional stability and the experience of caring by God. Because the formational type is deserted or is built up in unnoticeable urban areas. The religious factors, for example, museums, special pray, Station of the Cross, Rosary way, statues of the Virgin Mary, catholic sculptures, etc. in the selective type are placed in the corners of the catholic sacred places to provide the opportunity of holy experience to pilgrims. But the level and the intensity of healing depends on the matter as to how much pilgrims experience religious factors voluntarily. Lastly, the participatory type means the experience of various religious factors following scheduled programs. The experience is for the group of pilgrims, not a person; and the human relationship via the religious experience spiritualizes the network of interest towards other participants. Furthermore, the spiritualized open mind towards other people becomes the power that can arrive at the emotional stability, the relief of stress, and the in-depth and authentic healing. Ultimately, the spiritual healing through religious factors is to realize human finitude and dedicate one's own self to God; in addition, the spiritual therapeutic landscapes are the place that can carry out such a spiritual ritual without any restraint.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.11-11
• /
• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.686-693
• /
• 2018

After the Sewol ferry-sinking incident in 2014, the public interest in safety at sea increased. In order to save and secure the initial response time required for sea rescues, not only the rescue organization, but also the victim needs to save and maintain golden time to secure the necessary time for rescue personnel. The purpose of this study was to investigate ways to maintain the psychological stability of victims during their rescue in the case of a mass rescue operation by using the oil boom installed on board oil spill response vessels. Through buoyancy tests and the development of oil booms in sea areas, it confirmed the buoyancy of two adults weighing 70 kg each per meter of oil boom could be maintained when a lifeline was installed on the side of the oil boom, and that it was possible to keep afloat four persons weighing 70 kg each on both sides of the oil boom. It also confirmed the buoyancy for three adults weighting 70 kg each per eight meters was maintained when riding on the top of the oil boom. As a method of rescue, it was found that the fastest and most accurate way to rescue victims was a rescue boat held at the rear end of the oil boom to lead to victims. In conclusion, the rescue team could utilize the oil boom installed on board the oil spill response vessel located near the marine accident site to save and secure the initial response time required for the rescue team to arrive. The victims in distress holding onto the lifeline or riding on the top of oil boom kept afloat at sea could maintain their psychological stability until the mass rescue operation initiated.