• Clean Technology
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• v.28 no.3
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• pp.218-226
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• 2022

As a result of the recent social transformation towards a hydrogen economy and carbon-neutrality, the demands for hydrogen energy have been increasing rapidly worldwide. As such, eco-friendly hydrogen production technologies that do not produce carbon dioxide (CO₂) emissions are being focused on. Among them, ammonia (NH₃) is an economical hydrogen carrier that can easily produce hydrogen (H₂). In this study, Ru/Al₂O₃ catalyst coated onmetallic monolith for hydrogen production from ammonia was prepared by a dip-coating method using a catalyst slurry mixture composed of Ru/Al₂O₃ catalyst, inorganic binder (alumina sol) and organic binder (methyl cellulose). At the optimized 1:1:0.1 weight ratio of catalyst/inorganic binder/organic binder, the amount of catalyst coated on the metallic monolith after one cycle coating was about 61.6 g L^-1. The uniform thickness (about 42 ㎛) and crystal structure of the catalyst coated on the metallic monolith surface were confirmed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Also, a numerical optimization regression equation for NH3 conversion according to the independent variables of reaction temperature (400-600 ℃) and gas hourly space velocity (1,000-5,000 h^-1) was calculated by response surface methodology (RSM). This model indicated a determination coefficient (R²) of 0.991 and had statistically significant predictors. This regression model could contribute to the commercial process design of hydrogen production by ammonia decomposition.

• Korean Journal of School Psychology
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• v.17 no.1
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• pp.17-38
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• 2020

This study examined the factor structure of the Child Behavior Checklist Dysregulation Profile(CBCL-DP) for school-aged children in Korea identified differences in the level of maladjustment and problematic behaviors between the clinical group which had characteristics of CBCL-DP and the control group which did not. Confirmative factor analysis was performed on three alternative models from the literature to determine which was the most appropriate factor structure for the CBCL-DP. The result showed that the bi-factor model fit the sample data better than both the one and second-factor models. To confirm that the bi-factor model was the most appropriate factor structure, regression paths with relevant variables examined. The showed that CBCL-DP with the bi-factor model was associated with executive function difficulty as reported by parents and with school adjustment and all sub-factors of strength and difficulty as reported by teachers. The results also showed that this model had a different relationship with anxiety/depression, aggressive behavior, and attention problems than the other models. The clinical group was shown to have more executive function difficulty, worse adjustment of school life and to be less likely to engage in desired behaviors than the control group. These results indicate the CBCL-DP is more related to negative outcomes than any other factor, and that the bi-factor model was found to best fit the sample data, consistent with other studies. The early discovery of CBCL-DP can be used to provide interventions for high-risk children who exhibit emotional and behavioral problems, making its detection a significant diagnostic tool. The implications of these result, the limitations of this study, and areas for future research are discussed in this paper.

• Journal of the Korean Applied Science and Technology
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• v.39 no.3
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• pp.397-406
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• 2022

This study is an experimental study on the single group pre-post test design for the effects of the exercise program combined with telephone coaching on postural balance, grip strength and depression of the elderly living alone. The subjects of this study were 20 elderly living alone who registered at a senior welfare center located in S City, Gyeonggi-do. A total of 12 session programs were applied from July 3 to October 14, 2021. Before and after the program, the participant's home was visited and 4 stage standing balance test(4 SBT), grip strength and depression were measured. The contents of the intervention consisted of elastic bands and grip balls, and weekly telephone coaching interventions were provided. In the result of this study, the exercise program combined with telephone coaching were statistically significant differences in 4 SBT(3stage)(t=-2.37, p=.029), 4 SBT(4stage)(t=-2.46, p=.024), right grip strength(t=-2.18. p=.042) and depression(t=2.82, p<.001). Therefore, it is expected that the exercise program combined with telephone coaching can be applied as a nursing intervention to improve postural balance, grip strength and reduce depression in the elderly living alone in the community.

• Korean Journal of Culture and Social Issue
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• v.27 no.4
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• pp.561-584
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• 2021

This study was conducted to classify 601 Korean adults into latent classes according to their love types and identify the differences in depression and find variables that affect the latent classes classification. As a result of the latent class analysis, the latent group for love types of Korean adults were classified into the L-H (7.7%) group, which showed the highest level of all three factors of intimacy, passion, and commitment, and the L-MH (33.6%) group, which all three factors were higher than the average, the L-M (39.8%) group with the mean of all three factors, the L-ML (14.6%) group with all three factors lower than the mean, and the L-L (4.3%) group with the lowest all three factors. Also, as a result of ANOVA, the L-MH group was psychologically healthier and more adaptive than the L-ML group. As a result of multinomial logistic analysis, females were more likely to belong to L-M, L-ML and L-L groups than males. In addition, singles were more likely to belong to the L-M and L-ML groups than those who were married. Also, the higher the anxiety attachment level, the higher the likelihood of belonging to the L-M, L-ML, and L-L groups than the L-H and L-MH groups, the L-ML and L-L groups than the L-M groups, and the L-L group rather than the L-ML groups. However, age, neuroticism, and emotional regulation did not affect the classification of latent classes. This study is meaningful in that it identified the various latent classes for the love types of Korean adults more three-dimensionally and suggested the possibility of differential interventions according to the characteristics of each group.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.506-520
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• 2022

Purpose: Physical activity (PA) has a beneficial effect on the prevention of arteriosclerosis in healthy adults. The purpose of this study was to analyze the relationship between PA measured using an accelerometer and arterial stiffness in healthy Korean adults. Methods: This study involved 87 subjects (36.8% women) aged 20-64 years. PA was evaluated using an accelerometer (wGT3X-BT, ActiGraph, Florida, USA) for 7 days. Based on the results of the accelerometer measurement, subjects were classified into active and inactive groups according to the World Health Organization (WHO) PA guidelines. The brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index (ABI) to assess arterial stiffness were measured by a non-invasive vascular screening device (VP-1000 Plus, Omron). Results: The average age of the study subjects was 47.7 ± 11.3 years and the WHO PA guideline achievement rate was 29.9%. There was no significant difference in arterial stiffness (baPWV and ABI) between the active and inactive groups. In females, the time spent in light PA were positively correlated with ABI (r = 0.396; p < 0.05) and the number of sedentary bouts over 50 minutes was inversely correlated with ABI (r = -0.402; p < 0.05). However, there was no significant correlation between PA and arterial stiffness in males. Conclusions: The results of this study suggest that light PA and sedentary behavior have a positive correlation with arterial stiffness in females.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.505-513
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• 1996

This study was conducted to investigate the variation of chemical components in stagnant water under different mulching amount of barley straw after combine harvesting and the effect of stagnent water on the germinatidn and seedling elongation at early growth stage in rice. pH was lower in barley straw mulching than non-mulching and decreased with increasing of mulched barley straw but was not different among treatments in stagnant water at 15 days after flooding. Dissolved oxygen decreased with the increasing of mulched barley straw and increased with the passing of time, while saline content increased with the increasing of mulched barley straw, showing significant difference among treatments, was peaked at 15 days after flooding and thereafter, decreased. NH4-N was higher 5 days after flooding with thicker barley straw mulching but was not different at 10 days. N $O_3$-N increased up to 10 to 15 days after flooding and increased with thicker barley straw mulching. Water soluble phosphorus and cation content ( $K^{+}$, $Ca^{2+}$, $Mg^{2+}$)were higher in thicker barley straw mulching and peaked at 10 and 15 days after flooding. Germination rate was decreased by thicker straw mulching and was high in order of medium late, medium and early maturing rice variety. Keumobyeo, Gancheokbyeo, Ilpumbyeo, Dongjinbyeo and Gyehwabyeo showed higher germination rate. Seedling elongation at early growth stage was poorer with increasing of barley. straw mulching. Ilpumbyeo had good seedling elongation in one time amount of barley straw mulching and Shinunbongbyeo, Unjangbyeo, Nonganbyeo and Dongjinbyeo had poorer, in two times.mes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.103-111
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• 1988

This study was carried out with two cultivars under two levels of pH and four levels of nitrogen fertilization in a field and nutri-culture experiments to obtain the information about the effects of pH and nitrogen fertilization on the growth and yield of soybean. Acidic condition suppressed the growth of soybean plants, and thus yield and yield components of soybean decreased under acidic condition. But they increased with increased nitrogen fertilization. Especially, these respones were more remarkable under acidic condition and in the variety Jangbaegkong. Grain yield of soybean were highly correlated with the content of allantoin and total nitrogen of soybean plants in the variety Jangbaegkong, but this was not in the variety Danyeobkong. The content of protein and fat of soybean seeds decreased under acidic condition, and more nitrogen fertilization increased the protein content, but decreased the fat content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.224-233
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• 1987

Most of the japonica rice varieties preferred for high eating quality are liable to lodging even under moderate rate of nitrogen application. This lodging liability has been a critical limit even for proper evaluation of physio-logical characteristics of those varieties exhibitable under higher nitrogen levels. Use of recent inhibitors of gibberellin biosynthesis such as ‘Pac1obutrazol’ may allow us to overcome this barrier. The responses of four high eating quality varieties to nitrogen application to the level of 150kg N per ha were evaluated with and without use of Paclobutrazol in comparison with a non-lodging, improved short japonica, Dongjin and a non-lodging, high yielding indica x japonica Milyang 23. The four were Damageum (the best eating quality in the 1930s), Nongrim 6 (the best in the 1960s), Chuchung (the best since 1970s), Koshihikari (the best in Japan since 1960s). As expected increased application of nitrogen increased plant height, length of the 3rd internode, and lodg-ing liability, being measured as culm breaking load, in all varieties tested and caused actual lodging in the fiel from the 50kg Nfha level in Damageum and Koshihikari and at the level of l50kg Nfha in Nongrim 6. Applica-tion of Pac1obutrazol (0.6%G) 15 days before heading reduced plant height, length of the 3rd internode and lodging liability being measured as culm breaking load in all varieties tested. However, the application of Pac1obutrazol during active tillering stage resulted in decreased culm breaking load in Damageum, Nongrim 6, and Koshihikari in spite of the decreased plant height and culm length as in the other varieties. Maximum yield was obtained with 100kg Nand 30kg Pac1obutrazol at 15 days before heading in Nongrim 6, 150kg N and 30kg Pac1obutrazol at 15 days before heading in Damageum, and 150kg N and 20kg Paclobutrazol at 20 days after transplanting plus 30kg Paclobutrazol at 15 days before heading in the variety Koshinhikari and Chuchung. Under a sensory evaluation of cooked rice, the four high eating quality varieties were not different in rank and Paclobutrazol treated rice was not distinguished from the untreated in eating quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.662-669
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• 1995

To clarify the effect of temperature during ripening on grain quality, rice plant which was grown under normal natural conditions untill heading stage was subjected various temperature regimes during grain filling stage. Three varieties, Odaebyeo, Hwaseongbyeo and Dongjinbyeo were used. Grains on primary and secondary-rachis branches were harvested seperately and measured specific gravity, grain size and weight. The optimum daily temperature for grain filling of rice during ripening period was about 22$^{\circ}C$ and grain filling under alternating temperature(26/18$^{\circ}C$, day /night) was better than constant temperature (22 /22$^{\circ}C$) based on 1, 000-grain weight and yield. Grain size based on volume per grain was smallest under the constant temperature of 22 /22$^{\circ}C$. The size of secondary-rachis branches was smaller than primary-rachis branch. The difference in size between primary and secondary-rachis branches was biggest in Hwaseongbyeo, followed by Odaebyeo and Dongjinbyeo. The temperature regimes treated did not influence the grain size difference between branches so much. The 1000-grain weight was lighter under high temperature than low temperature in Odaebyeo, but reversed tendency was observed in Dongjinbyeo of secondary rachis-branches.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.185-200
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• 2022

The risk of various hazardous substances in aquatic environment comprises not only the concentration of substances in the environmental medium but also their accumulation in fish through complex food web and the health risks to humans through the fish. In Korea, the monitoring of residual toxicant in aquatic ecosystems began in 2016 following the enforcement of the Acts on registration and evaluation for the management of chemicals used in daily life (consumer chemical products), and attention has been paid to potentially hazardous substances attributed to them. Recently, studies have been carried out to investigate the distribution of these hazardous substances in the ecosystem and calculate their emission factors. These include the accumulation and transport of substances, such as detergents, dyes, fragrances, cosmetics, and disinfectants, within trophic levels. This study summarizes the results of recently published research on the inflow and distribution of hazardous substances from consumer chemical products to the aquatic environment and presents the scientific implication. Based on studies on aquatic environment monitoring techniques, this study suggests research directions for monitoring the residual concentration and distribution of harmful chemical substances in aquatic ecosystems. In particular, this study introduces the directions for research on trophic position analysis using compound specific isotope analysis and trophic magnification factors, which are needed to fulfill the contemporary requirements of selecting target fish based on the survey of major fish that inhabit domestic waters and assessment of associated health risk. In addition, this study provides suggestions for future biota monitoring and chemical research in Korea.