• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.132-132
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• 2013

Colloidal synthesis of nanoparticles with well-controlled size, shape, and composition, together with development of in situ surface science characterization tools, such as ambient pressure X-ray photoelectron spectroscopy (APXPS), has brought new opportunities to unravel the surface structure of working catalysts. Recent studies suggest that surface oxides on transition metal nanoparticles play an important role in determining the catalytic activity of CO oxidation. In this talk, I will outline the recent studies on the influence of surface oxides on Rh, Pt, Ru and Co nanoparticles on the catalytic activity of CO oxidation [1-3]. Transition metal nanoparticle model catalysts were synthesized in the presence of poly(vinyl pyrrolidone) polymer capping agent and deposited onto a flat Si support as two-dimensional arrays using the Langmuir-Blodgett deposition technique. APXPS studies exhibited the reversible formation of surface oxides during oxidizing, reducing, and CO oxidation reaction [4]. General trend is that the smaller nanoparticles exhibit the thicker surface oxides, while the bigger ones have the thin oxide layers. Combined with the nature of surface oxides, this trend leads to the different size dependences of catalytic activity. Such in situ observations of metal nanoparticles are useful in identifying the active state of the catalysts during use and, hence, may allow for rational catalyst designs for practical applications. I will also show that the surface oxide can be engineered by using the simple surface treatment such as UV-ozone techniques, which results in changing the catalytic activity [5]. The results suggest an intriguing way to tune catalytic activity via engineering of the nanoscale surface oxide.

• International Journal of Aeronautical and Space Sciences
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• v.2 no.1
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• pp.12-19
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• 2001

Study of turbulent mixing layers has been a popular subject from the point of view of both practical application and phenomenological importance in engineering field. Turbulent mixing layers can be applied in many fields where rapid transition to turbulence is desirable in order to prevent boundary layer separation or to enhance mixing. The ability to control mixing, structure and growth of the shear flow would obviously have a considerable impact on many engineering applications. In addition to practical applications, free shear flows are one of the simplest flows to understand the fundamental mechanism in the transition process to turbulence. After the discovery of large-scale vortical structure in free shear flows many researchers have investigated the physical mechanism of generation and dissipation processes of the vortical structure. This study investigated the role of the large-scale vortical structures in the turbulent mixing layer using LES(Large-Eddy Simulation). The result shows that the pairing interaction of the vortical structure plays an important role in the growth rate of a mixing layer. It is found that the turbulence quantities depend strongly on the velocity ratio. It is also found that the vorticity in the high-velocity-side can extract energy from the mean flow, while the vorticity in the low-velocity-side lose energy by the viscous dissipation. Finally the results suggest the guideline to obtain the desired flow by control of the velocity ratio.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.615-619
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• 2007

MgO layer plays an important role for plasma display panels (PDPs). In this experiment, ion beam assisted deposition (IBAD) methode was uesed to deposit a MgO thin film and the assisting oxygen ion beam energy was varied from 100 eV to 500 eV. In order to investigate the relationship between the secondary electron emission and the defect levels of the MgO layer, we measured the cathodoluminescence (CL) spectra of the MgO thin films, and we analyzed the CL peak intensity and peak transition. The results showed that the assisting ion beam energy played an important role in the peak intensity and the peak transition of the CL spectrum. The properties of MgO thin film were also analyzed using XRD and SEM, these results showed the assisting ion beam energy had direct effect on characteristics of MgO thin film.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.833-840
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• 2021

This paper examines the effect of the interest rate set by Bank Indonesia on financial system stability as measured by the credit gap in Indonesia for quarterly data for the period 1976 Q1 to 2019 Q4. We suppose that the relationship between the Central Bank rate and the credit gap is non-linear. Hence, this study applies a smooth transition regression (STR) model to investigate the relationship between these variables. Our results are: first, by performing STR estimation we obtained a threshold level of Central Bank rate of 2.01. Second, a decrease in the Central Bank rate results in a reduction in the credit gap when the Central Bank rate is above or below the threshold level. The effect of the Central Bank rate is five times greater for the high regime than for the low regime. Third, we find evidence that the effect of the exchange rate, economic growth, inflation, and GDP per capita on the credit gap for the high regime is the opposite of the low regime. We suggest that policymakers need to keep the Central Bank interest rate low and stable so that the role of the bank as a financial intermediary remains stable and conducive to strengthening financial stability.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.6
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• pp.533-540
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• 2023

Sweroside is a natural monoterpene derived from Swertia pseudochinensis Hara. Recently, studies have shown that sweroside exhibits a variety of biological activities, such as anti-inflammatory, antioxidant, and hypoglycemic effects. However, its role and mechanisms in high glucose (HG)-induced renal injury remain unclear. Herein, we established a renal injury model in vitro by inducing human renal tubular epithelial cell (HK-2 cells) injury by HG. Then, the effects of sweroside on HK-2 cell activity, inflammation, reactive oxygen species (ROS) production, and epithelial mesenchymal transition (EMT) were observed. As a result, sweroside treatment ameliorated the viability, inhibited the secretion of inflammatory cytokines (TNF-α, IL-1β, and VCAM-1), reduced the generation of ROS, and inhibited EMT in HK-2 cells. Moreover, the protein expression of SIRT1 was increased and the acetylation of p65 NF-kB was decreased in HK-2 cells with sweroside treatment. More importantly, EX527, an inhibitor of SIRT1, that inactivated SIRT1, abolished the improvement effects of sweroside on HK-2 cells. Our findings suggested that sweroside may mitigate HG-caused injury in HK-2 cells by promoting SIRT1-mediated deacetylation of p65 NF-kB.

• Korean Journal of Culture and Social Issue
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• v.16 no.1
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• pp.81-101
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• 2010

The purposes of this study were: (a) to examine the relationship between parental/occupational role reconstruction and psychological well-being in middle and old age, (b) to investigate the psychological factors to affect parental/occupational roles reconstruction. The role reconstruction was measured as the extent to obsess with parental and occupational role in transition. Mail survey was conducted on 378 Japanese married men and women in ages between 50 and 69. As results, the hypothetical pathway was identified in women as follows. The obsession with parental and occupational roles raised parental and occupational role loss anxiety. And both of role loss anxiety lower psychological well-being. For men, obsessed with the occupational role was significantly influenced by autonomy, gender role attitude, social support network. For women, gender role attitude significantly influenced on occupational and parental role obsession, and social support networks had significant impact on parental role obsession. Results of this study were discussed in terms of the importance of role reconstruction in middle and old age, gender difference in role reconstruction according to gender role socialization.

• Journal of the Korean Home Economics Association
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• v.39 no.10
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• pp.187-204
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• 2001

The purpose of this study was to investigate the relationship of care-oriented morality and justice-oriented morality with gender and sex-role identity in high school students. Care-oriented morality was assessed by Modified Care-based Morality Measure based on Gilligan's(1982) theory. Justice-oriented morality was assessed by the Korean Defining Issues Test(DIT). Sex role identity was assessed by the Korean Sex Role Inventory(KSRI). The subjects of this study were 157 females and 143 males, the age of 17 to 19 years old. The average level of care-oriented morality of the subjects was on level 1.5(transition from survival to responsibility) and the P score(post conventional level) of justice-oriented morality was pretty high. There were significant differences between females and males in the levels of care-oriented morality as well as justice-oriented morality. There were significant differences in sex role identity types by level of care-oriented morality. On the other hand, there was no significant difference in sex role identity types by level of justice-oriented morality.

• Korean Journal of Childcare and Education
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• v.17 no.1
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• pp.125-150
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• 2021

Objective: The purpose of this study is to explore the parental role that men experience during parental leave. From the moment when a man decides to take parental leave, to his experiences during parental leave, and to the father's role that lasts until after reinstatement, this course will be examined. Methods: The subjects of this study were five fathers who were taking parental leave. Data were collected through semi-structured interviews done on Zoom, telephone calls and e-mail. Results: The results are as follows. First, the motive for the father's decision to take parental leave was that he wanted to take a break from work and to spend time with his children. Second, the father had experiences of a caregiver and secure-base for his ones. Also, he experienced intergenerational transmission of his parental role. Third, the father's role was maintained even after parental leave. Conclusion/Implications: The decision to take parental leave was a process of conformation of one's own decision. The parental role of the father was experienced through daily life and interaction with his children. And that continued even after parental leave.

• Journal of Science and Technology Studies
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• v.16 no.2
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• pp.65-98
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• 2016

Living Lab is being introduced and applied as an innovation model driven by social entities (residents, users, etc.) and as an innovation place based on local and field. This study analyzed three living lab cases of Bukchon IoT living lab, Seong-Daegol energy transition living lab, and Daejeon Geonneoyu project, which were designated as 'Living Lab' to solve local problems. We analyzed the local problem, the problem solving goal, the role of each participant and the subject, the living lab promotion system, the significance in each case. In addition, the types and characteristics of living labs were elucidated and future development plans were discussed. The result is as follow. First, each case has a tendency to link science technology and ICT with local problem solving though there is a difference between the technologies used. Second, local residents played a leading role in the whole living lab process from problem identification to technical experimentation, diffusion and application. Third, the role of the intermediaries commonly played an important role in the operation of the living lab. Last but not least, each case has different types of living lab. Bukchon IoT living lab being operated as a project by the government / municipality to create a living lab activity-base or to support actors' activities. On the other hand, the Seong-Daegol energy transition living lab and Daejeon Geonneoyu project were conducted by the civil society itself to define problems and explore technologies in order to solve local problems.

• Journal of Life Science
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• v.23 no.8
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• pp.970-977
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• 2013

The epithelial-to-mesenchymal transition (EMT) plays an essential role in embryogenesis and is involved in tumor metastasis and invasion; it significantly contributes to tumor progression and aggressiveness. The EMT is characterized by a loss of epithelial cell polarity as a result of the reduced expression of epithelial E-cadherin, a hallmark of the EMT, and the acquisition of mesenchymal-like cell morphology. Reactive oxygen species (ROS) such as $O_2{^-}$, $H_2O_2$, and $OH^-$ have been demonstrated to induce the EMT; although Snail is involved in ROS-induced EMT by transcriptionally repressing E-cadherin, its mechanism is not fully understood. In this study, we examined the effects of early growth response 1 (Egr-1) overexpression in noninvasive breast tumor cell line MCF-7 cells. Upon Egr-1 overexpression, MCF-7 cells lost epithelial cell polarity and became more spindle-shaped, indicating that Egr-1 may induce EMT. We found that Snail is implicated in Egr-1 induced EMT. We further demonstrate that the Egr-1-Snail axis is activated by ROS and plays a critical role(s) in ROS-induced EMT.