• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.749-761
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• 2024

The purpose of this study analyzes the cultural identity, learning motivation, learning strategies, and second language acquisition trends of Chinese students living in Korea to reveal the structural relationship between these four variables, thereby revealing the cultural identity, learning motivation, and learning strategies of international students in the Korean language learning process. The purpose is to provide basic data to promote . This study verified reliability and validity through a preliminary survey targeting 200 people. This survey was conducted on 1,006 Chinese students studying abroad at six universities in Seoul, Gyeonggi-do, Busan, and Chungcheong-do from May 28 to June 15, 2023. As a result of the study, first, the structural relationship between variables was that cultural identity had a positive effect on learning motivation, learning strategies, and second language acquisition. Second, learning motivation had a positive (+) effect on learning strategies and second language acquisition. Third, learning strategies had a positive (+) (+) effect on second language acquisition. Fourth, learning motivation and learning strategy between cultural identity and learning strategy were found to play a positive (+) mediating role and multiple mediating roles. Therefore, in order to promote international students' cultural identity, learning motivation, and learning strategies in the Korean language learning process, it is necessary to increase opportunities for international students to directly experience the formation of cultural identity and to organize and teach a multifaceted curriculum centered on practice.

• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.175-183
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• 2024

Research into optical signal processing using photonic integrated circuits (PICs) has been actively pursued in various fields, including optical communication, optical sensors, and quantum optics. Among the materials used in PIC fabrication, polymers have attracted significant interest due to their unique characteristics. To fabricate polymer-based PICs, establishing an accurate manufacturing process for the cross-sectional structure of an optical waveguide is crucial. For stable device performance and high yield in mass production, a process with high reproducibility and a wide tolerance for variation is necessary. This study proposes an efficient method for fabricating polymer optical-waveguide devices by introducing the atomic layer deposition (ALD) process. Compared to conventional photoresist or metal-film deposition methods, the ALD process enables more precise fabrication of the optical waveguide's core structure. Polyimide optical waveguides with a core size of 1.8 × 1.6 ㎛² are fabricated using the ALD process, and their propagation losses are measured. Additionally, a multimode interference (MMI) optical-waveguide power-splitter device is fabricated and characterized. Throughout the fabrication, no cracking issues are observed in the etching-mask layer, the vertical profiles of the waveguide patterns are excellent, and the propagation loss is below 1.5 dB/cm. These results confirm that the ALD process is a suitable method for the mass production of high-quality polymer photonic devices.

• School Science Journal
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• v.12 no.1
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• pp.113-126
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• 2018

R&E (Research and Education) program has been emphasized since it can improve student's scientific thinking, problem solving ability, and creativity, with providing diverse opportunities for scientific research experiences that are difficult to access in this curriculum. In this study, we reconstructed a method of calculating high resolution sea surface temperature data in the coastal region around Korea using satellite data, and developed it into a R&E program for science-gifted students. In order to calculate the high resolution sea surface temperature data in the seas around Gyeonggi Bay and to understand the spatio-temporal distribution, 9 Landsat 8 OLI/TIRS (Operational Land Imager and Thermal InfraRed Sensor) satellite data were collected from December 21, 2013 to November 30, 2017. To understand the accurate sea surface temperature distribution, land area was masked by using SRTM (Shuttle Radar Topography Mission) DEM (Digital Elevation Model) data, tidal flat was detected by applying the land use classification algorithm, and cloud was removed by applying a threshold to visible wavelength band of Landsat 8 OLI/TIRS satellite. High resolution sea surface temperature data in the seas around Gyeonggi Bay was calculated by applying MCSST (Multi-Channel Sea Surface Temperature) to preprocessed Landsat 8 OLI/TIRS satellite data. In order to develop the R&E program that can be used practically, we simplified the research process and developed learning worksheets suitable for each research stage so that students can perform the research process step by step. We conducted R&E program for students of science and gifted students from June 24, 2017 to January 13, 2018 and confirmed the applicability of R&E program based on satellite data.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.348-355
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• 1998

The developments of various processed foods and the high quality dried fruits, in particular, are urgently needed for the enhancement of fruit consumption and their competitive values. Therefore, in this study, three variables by three level factorial design and response surface methodology were used to determine optimum conditions for osmotic dehydration of kiwifruit. The relationships of moisture losses, solid gains, weight reductions, sugar contents, titratable acidities and vitamin C contents depending on changes with temperature, sugar concentration and immersion time were investigated. The moisture loss, solid gain, weight reduction and reduction of moisture content after osmotic dehydration were increased as temperature, sugar concentration and immersion time increased. The effect of concentration was more significant than those of temperature and time on mass transfer. Sugar content was increased by increasing sugar concentration, temperature, immersion time during osmotic dehydration. Titratable acidity and vitamin C content were increased by decreasing temperature, immersion time and increasing concentration during osmotic dehydration. The regression models showed a significant lack of fit (P>0.05) and were highly significant with satisfying values of $R^2$. At the given conditions such as $66{\sim}69%$ moisture content, above $24^{\circ}Brix$ sugar content and more than 23 mg% vitamin C, the optimum condition for osmotic dehydration was $37^{\circ}C,\;55^{\circ}Brix$ and 1.5 hour.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.451-469
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• 1996

To identify the drug abuse status and its determinant factors in high school boys in Taegu, the study was performed from April to May, 1995. Study population were selected by cluster sampling method and total 5,665 students replied to the self-administered questionnaire survey (2,207 in academic high school, 3,458 in business high school). The major findings were as follows; The proportion of drinking, smoking experience was 55.0%, 45.8%, respectively, and the proportion of current drinker, current smoker was 27.2%, 27.5%. The drinking, smoking experience rate of second grade students was higher than first grade and it was higher in business high school boys. The proportion of a stimulant, a hallucinogen, hemp leaf cigarets experience was 3.2%, 1.6%, 0.1%, respectively. Drug abuse had significant association with home environment(lower economic status, frequent move, death of father or mother, apart from family), parents environment(parents' indifference, parents' drinking and smoking, etc.), school life(lower school grades, intimate friend's drug abuse, etc.), generous attitude to drug abuse, higher level of stress. Students who replied that the law prohibited immature person(students) from drinking and smoking showed lower drug abuse rate. In multiple logistic regression analysis, second grade students, business high school students, parents' indifference, lower school grades, intimate friend's drug abuse, no recognition of the fact that the law prohibits high school students from drinking and smoking, generous attitude to drug abuse, higher level of stress were significantly related with alcohol abuse and smoking. Other drugs abuse were related with above factors. On consideration of above findings, to prevent students from drug abuse, we have to try together in house, school, and society.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.43-50
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• 2015

In this study, single PCR and multiplex PCR tests were examined for identification of four types of squid species (giant squid, cuttlefish, octopus, beka squid) purchased from fish market as well as aquatic processed products in Busan. To design the specific primers against each species, the nucleotide sequences of the mitochondrial 16s rRNA gene of Architeuthis dux, Todarodes pacificus, Enteroctopus dofleini, Enteroctopus megalocyathus, Uroteuthis chinensis, Uroteuthis duvauceli, Uroteuthis edulis groups were analyzed for the identification of each species registered in the GeneBank (www.ncbi.nlm.nih.gov) and have been used for comparative analysis. In order to obtain the size variation of amplified fragments on multiplex PCR, we designed KOJ-F, OJ-F, OCT-F, HAN-F, ALLR primers for each species. The optimal PCR conditions and primers were selected for four types of squid species to determine target base sequences in its PCR products. In the case of single PCR, giant squid was only amplified by KOJ-F/ALLR primer; cuttlefish was only amplified by OJ-F/ALLR primer; octopus was only amplified by OCT-F/ALLR primer; and beka squid was only amplified by HAN-F/ALLR primer. For multiplex PCR, the mixture of four kinds of genomic DNA (giant squid, cuttlefish, octopus, beka squid) been prepared as a template and used together with the mixture of KOJ-F/OJ-F/OCT-F/HAN-F/ALLR primers in the reaction. By the multiplex PCR, it is confirmed that four samples are correspond to multiple simultaneous amplicon. Finally, we validated the established methods of multiplex PCR in the aquatic processed products. Although the mitochondrial 16s rRNA primers used in this study was useful as a marker for detection of each species among them, the study indicated that the established multiplex PCR method can be more useful tool for monitoring the processed products.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.59-71
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• 2016

To investigate the sorption characteristics of Cs, which is one of the major isotopes of nuclear waste, on natural zeolite chabazite, XRD, EPMA, EC, pH, and ICP analysis were performed to obtain the informations on chemical composition, cation exchange capacity, sorption kinetics and isotherm of chabazite as well as competitive adsorption with other cations ($Li^+$, $Na^+$, $K^+$, $Rb^+$, $Sr^{2+}$). The chabazite used in this experiment has chemical composition of $Ca_{1.15}Na_{0.99}K_{1.20}Mg_{0.01}Ba_{0.16}Al_{4.79}Si_{7.21}O_{24}$ and its Si/Al ratio and cation exchange capacity (CEC) were 1.50 and 238.1 meq/100 g, respectively. Using the adsorption data at different times and concentrations, pseudo-second order and Freundlich isotherm equation were the most adequate ones for kinetic and isotherm models, indicating that there are multi sorption layers with more than two layers, and the sorption capacity was estimated by the derived constant from those equations. We also observed that equivalent molar fractions of Cs exchanged in chabazite were different depending on the ionic species from competitive ion exchange experiment. The selectivity sequence of Cs in chabazite with other cations in solution was in the order of $Na^+$, $Li^+$, $Sr^{2+}$, $K^+$ and $Rb^+$ which seems to be related to the hydrated diameters of those caions. When the exchange equilibrium relationship of Cs with other cations were plotted by Kielland plot, $Sr^{2+}$ showed the highest selectivity followed by $Na^+$, $Li^+$, $K^+$, $Rb^+$ and Cs showed positive values with all cations. Equilibrium constants from Kielland plot, which can explain thermodynamics and reaction kinetics for ionic exchange condition, suggest that chabazite has a higher preference for Cs in pores when it exists with $Sr^{2+}$ in solution, which is supposed to be due to the different hydration diameters of cations. Our rsults show that the high selectivity of Cs on chabazite can be used for the selective exchange of Cs in the water contaminated by radioactive nuclei.

• Tuberculosis and Respiratory Diseases
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• v.54 no.2
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• pp.210-218
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• 2003

Background : Sex specific cross sectional reference values for the lung function indices usually employ a linear model with a term for age and height. The purpose of this study was to determine the effects of the body mass index (BMI), the fat percentage of the body mass and the fat-free mass index (FFMI) on the forced expiratory volume curve. Methods : Between January 2000 and December 2001, a total of 300 subjects, 150 men and 150 women (mean age : $45{\pm}13$ years), with a normal lung function were enrolled in the study sample. This study measured the $FEV_1$, FVC and $FEF_{25-75%}$ from the forced expiratory volume curve by a spirometer and the body composition by a bioelectrical impedance method in all subjects. Multiple regression analysis was used in order to examine the effects of the body composition on the parameters derived from the forced expiratory volume curve. Results : After adjusting for age, the BMI and Fat percentage improved the descriptions of the FVC (p<0.05, $r^2=0.491$) and $FEV_1$ (p<0.05, $r^2=0.654$) in women. In contrast, the FFMI contributed significantly to the FVC (p<0.05, $r^2=0.432$) and $FEV_1$ (p<0.05, $r^2=0.567$) in men. The $FEF_{25-75%}$ correlated with the fat percentage in women (p<0.05, $r^2=0.337$). Conclusion : These results suggest that the BMI, the fat percentage and the FFMI are significant determinants of the forced expiratory volume curve. The plmonary function test, when considering the BMI, the fat percentage and the FFMI, might be useful in clinical applications.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.73-79
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• 2011

Purpose: The aim of this study was to evaluate the effect of repeated firings on the color of zirconia restoration with different shading method. Materials and methods: Three different types of zirconia frameworks (adding metallic pigments to the initial zirconia powder before sintering (Group NM), dipping the milled frameworks in dissolved coloring agents (Group KI), or application of liner material to the sintered white frameworks (Group KW) were used to support A3 shade dentin porcelain. Repeated firings (3, 5, or 7) were performed, color differences among ceramic specimens were measured using a colorimeter. Repeated measurements analysis of variance (ANOVA) was used to analyze the data for significant difference. The Tukey Honestly Significant Different (HSD) test was used to perform multiple comparisons (${\alpha}$ = .05). Results: 1. $L^*a^*b^*$ values of the ceramic systems were affected by the number of firings (1, 3, 5 or 7 firings) (P < .001) and shading methods (P < .001). 2. As the number of firings increased, the $L^*$ (for all groups) and $a^*$ value (for KW and NM groups) decreased and the $b^*$ value(for all groups) increased. 3. The mean color differences caused by repeated firings were perceptible (${\Delta}E$ > 1) for group KW and KI fired after 3 times, except for group NM fired after 7 times. 4. In order of decreasing ${\Delta}E$ value fired after 7 times, the values were group KI(${\Delta}E$ = 2.26) > group KW (${\Delta}E$ = 1.47) > group NM (${\Delta}E$ = 1.08) (P < .001). Conclusion: Repeated firings influenced the color of the zirconium-oxide all-ceramic specimens with different shading methods.

• Journal of dental hygiene science
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• v.13 no.1
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• pp.62-70
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• 2013

The aim of this study was to analyze factors related to xerostomia in adults aged 30 years and over. The data were analyzed using the t-test, one-way ANOVA and multiple linear regression analysis in the SPSS version 12.0 program. The results were as follow. 1. The respondents who were older than 51 years old, unemployed and had less than 3 million won of average monthly income were more aware of xerostomia (p<0.05). 2. The respondents who answered poor and moderate for their general and oral health and the group with duplicate medication and comorbidity were more aware of xerostomia (p<0.05). 3. The respondents that had problems in chewing, communication, ordinary activities and complained of pain discomfort and suffered from anxiety depression were more aware of xerostomia (p<0.001). 4. The respondents that answered frequent dryness on their skin, eyes, lips, and nasal mucosa were more aware of xerostomia (p<0.001). 5. Xerostomia showed highest correlation with quality of life ($\beta$=0.436) followed by the number of medications ($\beta$=0.239), sense of entire body dryness ($\beta$=0.200), feeling of hopelessness ($\beta$=0.160) and number of oral mucosa disease symptoms ($\beta$=0.099) (p<0.05). According to the results of the study, xerostomia may cause deterioration in quality of life. Thus, it is advised to improve the patient management system among dental professions to prevent various complications caused by xerostomia and conduct regular health education on the cause and management method of xerostomia.