• 한국노년학
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• v.40 no.1
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• pp.91-109
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• 2020

This study aims to investigate the interdependence of Korean middle and old-aged couples in the association between exercise and life satisfaction through grip strength trajectory. Data were drawn from the nationally representative Korea Longitudinal Study of Aging (KLoSA) collected from 2006 to 2016. The sample included couples over 45 years of age in the first wave and participated in all six waves of the survey (Ncouple=1,997). There were three steps for analyses: correlation, parallel latent growth curve model, tests of indirect effects of the mediation paths. Covariates included in the models were husbands and wives' characteristics (age, education, work status, chronic diseases, marital satisfaction, contact frequency with friends or neighbors) and couple's household income. Results showed husbands' and wives' life satisfaction and grip strength were interdependent upon each other. Also, exercise participation of both husbands and wives was associated with both husbands' and wives' life satisfaction via the initial level of grip strength of husbands. Moreover, exercise participation of only husbands was associated with wives' life satisfaction through the initial grip strength of husbands. These results suggest the aging processes of middle and old-aged couples need to be understood in the context of gender dynamics and couple interdependence.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.219-229
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• 2022

Bentonite is being considered as a candidate for buffer material in geological disposal systems for high-level radioactive wastes. In this study, the effect of cement-bentonite interactions on bentonite alteration was investigated by reviewing the literature on studies of cement-bentonite interactions. The major bentonite alteration by hyperalkaline fluids produced by the interaction of cementitious materials with groundwater includes cation exchange, montmorillonite dissolution, secondary mineral precipitation, and illitization. When the hyperalkaline leachate from the reaction of the cementitious material with the groundwater comes into contact with bentonite, montmorillonite, the main component of bentonite, is dissolved and a small amount of secondary minerals such as zeolite, calcium silicate hydrate, and calcite is produced. When montmorillonite is continuously dissolved, the physicochemical properties of bentonite may change, which may ultimately causes changes in bentonite performance as a buffer material such as adsorption capacity, swelling capacity, and hydraulic conductivity. In addition, the bentonite alteration is affected by various factors such as temperature, reaction period, pressure, composition of pore water, bentonite constituent minerals, chemical composition of montmorillonite, and types of interlayer cations. This study can be used as basic information for the long-term stability verification study of the buffer material in the geological disposal system for high-level radioactive wastes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.40-47
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• 2021

In this study, the structural behavior by the details of the lap region with the headed bar was estimated through finite element analysis. To solve the finite element analysis of the anchorage region with complex contact conditions and nonlinear behavior, a quasi-static analysis technique by explicit dynamic analysis was performed. The accuracy of the finite element model was verified by comparing the experimental results with the finite element analysis results. It was confirmed that the quasi-static analysis technique well reflected the behavior of enlarged headed bar connection. As a result of performing numerical analysis using 21 finite element models with various development lengths and transverse reinforcement indexes, it was confirmed that the increase of development length and transverse reinforcement index improved the maximum strength and ductility. However, to satisfy the structural performance, it should be confirmed that both design variables(development length and transverse reinforcement index) must be enough at the design criteria. In the recently revised design standard(KDS 14 20 52 :2021), a design formula of headed bar that considers both the development length and the transverse reinforcing bar index is presented. Also the results of this study confirmed that not only the development length but also transverse reinforcing bars have a very important effect.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.609-618
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• 2021

The spread and damage of COVID-19 are putting significant pressure on the world, including Korea. Most countries place restrictions on movement and gathering to minimize contact between citizens and these policies have brought new changes to social patterns. This study generated traffic volume data on the scale of a road network using taxi movement data collected in the early stages of the COVID-19 third pandemic to analyze the impact of COVID-19 on movement patterns. After that, correlation analysis was performed with the data of confirmed cases in Daegu Metropolitan City and Local Moran's I was applied to analyze the effect of spatial characteristics. As a result, in terms of the overall road network, the number of confirmed cases showed a negative correlation with taxi driving and at least -0.615. It was confirmed that citizens' movement anxiety was reflected as the number of confirmed cases increased. The commercial and industrial areas in the center of the city confirmed the cold spot with a negative correlation and low-low local Mona's I. However, the road network around medical institutions such as hospitals and spaces with spatial characteristics such as residential complexes was high-high. In the future, this analysis could be used for preventive measures for policymakers due to COVID-19.

• Journal of Christian Education in Korea
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• v.70
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• pp.303-337
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• 2022

The purpose of this study is to realize Ontact PBL that can sufficiently contain interactive elements that can increase the perception of reality between professors and students in an environment without human contact. This is a class designed, developed, and operated ontact PBL for the first semester of 2021. As a result of diagnosing the realism of teaching and learning for students who took the class, the average teaching realism improved significantly by 0.95. This was found to be effective in improving the sense of realism in teaching as there were many related opinions in the reflective journal on students' classes. In addition, there was an effect on learning presence, and it was confirmed that emotional presence, which is a sub-element of learning presence, significantly improved by 0.7, social presence by 0.5, and cognitive presence by 0.6. Learning presence also confirmed the students' reflection on the class, and it was possible to judge that Ontact PBL was effective in improving the sense of presence.

• Journal of the Korean GEO-environmental Society
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• v.24 no.3
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• pp.5-14
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• 2023

The dry unit weight of the soil can be obtained by measuring the weight of the oven dried soil. According to the Korean Industrial Standards (KS F), oven dried soil at 110±5℃ continuously increases in weight when exposed to air. However, there is no regulation on the weight measurement time of oven dried soil, making it difficult to accurately measure the dry weight. In this study, a method to easily determine the dry weight was presented through the analysis of the weight singularity that appears during weight measurement. The weight singularity represents the smallest value among the measured weights, and is the weight at which the effect of moisture absorption in the air of the sample is minimized. In the course of the experiment, a container was selected using a statistical analysis method, and a photograph of the soil samples were presented using an optical microscope. In addition, the temperature of the weight singularity was measured using a non-contact infrared thermometer. As a result of analyzing the weight singularity of six types of soil, including Jumunjin sand, Naeseong stream sand, Yecheon weathered granite soil, Jeju sand, Sabkha sand, and Ulleung sand, the weight singularity of oven dried sample appeared between 8 and 27 seconds after weight measurement, and the temperature ranged from 103.4 to 108.13℃. The weight decrease rate of the singularity was 0.0066 to 0.0085% depending on the soil samples.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.79-86
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• 2023

In this study, poly(lactic acid) (PLA) and Poly(butylene-adipate-co-terephthalate) (PBAT) composite films containing calcined oyster shell powder (OSP) were evaluated for the applicability of antimicrobial packaging. PLA/PBAT-OSP composite films were prepared using twin-screw extruder. The OSP composite was incorporated into PLA/PBAT blend with different ratios (0, 1, 3, 5 and 10%) and the effect of OSP in the PLA/PBAT matrix was evaluated. The PLA/PBAT-OSP composite films were evaluated for properties using FT-IR, SEM, TGA, DSC, UTM, UV-vis, and Contact angle, as well as antimicrobial property was examined according to ISO 22196 - Antimicrobial Plastic Test. As OSP was added, it showed high antimicrobial activities for both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. On the other hand, it was found that mechanical properties decreased as OSP was added. For the application of PLA/PBAT-OSP composite films as an antimicrobial packaging material, it is necessary to improve the dispersibility of OSP in the PLA/PBAT composite films and their physical properties at the same time.

• Journal of Korea Entertainment Industry Association
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• v.13 no.2
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• pp.47-56
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• 2019

This study conducted in-depth interviews with employees who worked at three different travel agencies in Seoul and had different employment years. In order to resolve emotional labor, we investigated and analyzed the positive effects of forest healing programs and tried to help both travel agents and forest healing operators. According to the analysis, the person who was selected for the H travel agency was interviewed at the forest healing experience center in Gapyeong in April 2018 and her job as an operator for the fifth year since she joined the company. He said that he suffered from depression due to emotional labor in the customer service process and that it has a positive effect through forest healing. Next, M travel agents conducted an interview in May 2018 at the forest experience center in Uiwang, and their job as a woman was product planning. In the case of emotional labor and physical illness in the work with customers, participants were interested in forest stability, people's humanity, and wooden crafts in particular. Lastly, participants of R travel agency conducted an interview at the forest experience center in Seoul in June 2018 and it was their 10th year as a man and their job as a tour contact. In order to solve the difficulties, I experienced forest experience in close geographical areas and received great help.

• Clean Technology
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• v.16 no.3
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• pp.191-197
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• 2010

Repair reaction of plasma damaged porous methyl doped SiOCH films was carried out with silylation agents dissolved in supercritical carbon dioxide ($scCO_2$) at various reaction time, pressure, and temperature. While a decrease in the characteristic bands at $3150{\sim}3560cm^{-1}$ was detectable, the difference of methyl peaks was not identified apparently in the FT-IR spectra. The surface hydrophobicity was rapidly recovered by the silylation. In order to induce effective repair in bulk phase, the wafer was heat treated before reaction under vacuum or ambient condition. The contact angle was slightly increased after the treatment and completely recovered after the subsequent silylation. Methyl groups were decreased after the plasma damage, but their recovery was not identified apparently from the FT-IR, spectroscopic ellipsometry, and secondary ion mass spectroscopy analyses. Furthermore, Ti evaporator was performed in a vacuum chamber to evaluate the pore sealing effect. The GDS analysis revealed that the open pores in the plasma damaged films were efficiently sealed with the silylation in $scCO_2$.

• Journal of Industrial Convergence
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• v.20 no.12
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• pp.107-115
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• 2022

The study attempted to identify the factors affecting the image of nurses in health and non-health university students after COVID-19. The study was collected from November 15, 2021 to 2011 and 28th, 2021, from 133 health-related and 123 non-health-related students in four universities. This data was analyzed by descriptive statistics, correlation, and multiple regression analysis using the SPSS 22.0 program. As a result of the study, whether the nurse image according to general characteristics is in the first grade of health-related college students(t=2.82, p=.006) showed a statistically significant difference. The nurse image of college students showed a positive correlation with the mass media image and major satisfaction in both health and non-health fields. For health-related college students, the image of mass media, major satisfaction, and first grade influence the image of nurses (F=40.42, p<.001)In the case of university students in non-health departments, it was found that only the media image affects the nurse image. (F=20.13, p<.001). In order to improve the image of nurses, it is necessary to have continuous interest in contact with the media through new media and to approach it systematically.