• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.270-275
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• 2005

Dust cores (compressed powder cores) of $Fe-6.0wt\%Si$ alloy with a size of $35\~180\;{\mu}m$ in diameter have been prepared by phosphate coatings and annealings at $600\~900^{\circ}C$ for 1 h in nitrogen atmosphere. Further the magnetic and mechanical properties of the powder cores were investigated. As a general trends, the compressive strength and core loss decreased with the increase in annealing temperature. When annealed at $800^{\circ}C$, the compressive strength was 15 kgf, the permeability and quality factor were 74 and 26, respectively. Moreover the core loss at 50 kHz and 0.1 T induction was $750\;mW/cm^3$, and the percent permeability under the static field of 50 Oe was estimated to be about 78. In addition, the cut-off frequency in the cure representing the frequency dependence of effective permeability was measured to be around 200 kHz. These properties of the $Fe-6.0wt\%Si$ alloy dust cores could be considered to be due to the good insulation effect of iron-phosphate coats, the decrease in magnetocrystalline anisotropy and saturation magnetostriction and the increase in electric resistivity.

• Nuclear Engineering and Technology
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• v.18 no.3
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• pp.200-208
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• 1986

The loss of coolant accident based on a double-ended cold leg break is analyzed with the discharge coefficient (Ca) of 0.4. This analysis covers the whole transient period from the start of depressurization to the complete refilling of the core by using RELAP4/MOD6-EM and RELAP4/ MOD6-HOT CHANNEL for the system thermal-hydraulics and the fuel performance during the blowdown phase respectively, and RELAP4/MOD6-FLOOD and TOODEE2 during the reflood phase. A simple analytical method has been developed to account for the lower plenum filling by approximating steam-water countercurrent flows and superheated wall effects at the downcomer during the refill period. Based on the informations. at the time of EOB (end-of-bypass), the refill duration time and the initial reflooding temperature were estimated and compared with the results from the RELAP4/MOD6, resulting in a good agreement. In addition, some parametric studies on the EOB were performed. The form loss coefficient between upper head and upper downcomer was found to be sensitive to the occurrence of the spurious EOB. Appropriate form loss coefficients should be taken into account to avoid the flow oscillations at the downcomer. The analyses with the six and three volume core nodalizations, respectively, show much similar trends in the system thermal-hydraulic performance, but the former case is recommended to obtain good results.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.105-106
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• 2003

Physiological responses (cortisol, glucose, lactic acid, osmolality and hematology) of olive flounder (Paralichthys olivaceus) to stressors associated with confinement and subsequent transport were investigated. Specimens were subjected to confinement stress for 3 h, prior to transport for 15 h. Two different size cohorts of the fish, large (839.6$\pm$162.7 g) and small (98.2$\pm$14.8 g), were used. Experimental cohorts of the fish were divided into 3 groups for blood sampling: group A, sampled at the beginning of confinement and 3 h before transport (BT, -3 h), after confinement and at the beginning of transport (BT, 0 h), 3 h after transport had begun (AT, 3 h), and after 15 h transport (AT, 15 h); group B, sampled at BT, 0 h, at AT, 3 h, and at AT, 15 h; and, group C, sampled at AT, 3 h, and at AT, 15 h. In the cohort of large fish, plasma cortisol levels of the A group were increased over time, from 4.2 ng/ml (BT, -3 h), to 92.0 ng/ml (BT, 0 h), 118.5 ng/ml (AT, 3 h) and 105.5 ng/ml (AT, 15 h). A similar pattern was evident in the B group, in which cortisol increased from 47.5 ng/ml (BT, 0 h) to 53.5 ng/ml (AT, 15 h); and, for the C group, in which cortisol increased from 43.5 ng/ml (AT, 3 h) to 71.5 ng/ml (AT, 15 h). Glucose levels of the A group also were significantly increased, from 39.5 mg/dl (BT, -3 h), to 121.0 mg/dl (BT, 0 h), 298.0 mg/dl (AT, 3 h) and 260.5 mg/dl (AT, 15 h). Lactic acid levels increased markedly during transport, from less than 1 mmol/L (BT, 0 h) to 12.0 mmol/L (AT, 15 h). Plasma osmolality increased from 405.5 mOsm/kg (BT, -3 h, for group A) to values near 500 mOsm/kg subsequent to confinement and transport. In the small-size cohort, plasma cortisol, glucose, lactic acid and osmolality levels showed similar but less pronounced trends than those observed for the large-size cohort. This research provides baseline data on cortisol, glucose, lactic acid, osmolality and hematological responses to confinement and transport, which should be useful to aquaculturists working with olive flounder and to scientists studying other flatfish species.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.129-134
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• 2009

Objectives of this study was to find the effect on two different nitrogen levels about agricultural characteristics of CNU rice lines developed at Crop Genetics and Breeding Laboratory, Chungnam Nat'l Univ.. Materials used were two black and one white glutinous rice lines, which were transplanted by hand with $30{\times}15cm$ at CNU paddy field on May 23, 2009. These lines was designed with two replication by two nitrogen levels as 7kg and 9kg per 10a. As the result; Culm length of all lines used were higher at 7kg than 9kg per 10a while panicle length was longer at 9kg nitrogen level. Tillers per plant of CNU 08-01 and CNU 08-02 lines except CNU 08-101 showed highly at 9kg level, but that of other leading varieties were not constant trends in spite of increasing nitrogen. Ripening ratio of CNU 08-01 and 08-02 lines were higher at 7kg but CNU 08-101 line was higher at 9kg. 1,000 grain weight and unhulled rice yield per 20 plants in all CNU lines were highly appeared at 9kg levels per 10a.

• Culinary science and hospitality research
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• v.21 no.6
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• pp.49-62
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• 2015

Give that statistical analysis is an essential component of foodservice-related research, the purpose of this review is to analyse research trends of statistical methods applied to foodservice-related research. To achieve these objective, this study carried out a content analysis on a total of 251 out of 415 research articles published in The Korean Journal of Culinary Research(TKJCR) from January 2010 to December 2013. Of the total 164 research articles focussing on natural science research, qualitative research, articles written in English were excluded from the scope of this study. The results of this study are as follows. First, it turned out that 269 research articles applied quantitative research methods, and only 10 articles applied qualitative research methods among the 279 research articles based on social science research methods. Second, 20 article (8.0%) among the 251 did not specify the statistical methods or computer programs that were used for statistical analysis. Third, it was found that 228 articles (90.8%) used the SPSS program for data analysis. Fourth, in terms of frequency of use, it was revealed frequency analysis was most used, followed in order by reliability analysis, exploratory factor analysis, correlation analysis, regression analysis, structural equation modeling, confirmatory factor analysis, t-test, variance analysis, and cross tabs analysis, However, 3 out of 56 research articles that used a t-test did not suggest a t-value. 10 out of 64 articles that used ANOVA and demonstrated a significant difference in between-group mean did not conducted post-hoc test. Therefore, the researchers with interest in foodservice fields need to keep in mind that choosing and applying the correct statistical technique both determine the value and the success or failure of a study. To enhance the value and success of a study, it is necessary to use the proper statistical technique in an efficient way in order to prevent statistical errors.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.8
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• pp.733-741
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• 2013

This is the first paper on the combustion characteristics of landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine, and it discusses the fundamental characteristics of fuel from the viewpoint of thermochemistry and thermodynamics and compares these results with experimental ones. The results show that the final pressures obtained from theoretical analysis vary under the same heating value owing to the change in the constant volume specific heat owing to the difference in the burned gas composition according to the fuel gas compositions; furthermore, the stoichiometric ratios and trends of analytical and experimental pressures coincide very well, although some minor differences are observed between the two. The root cause of the difference is the heat transfer, which changes the specific heat and lowers the temperature considerably, in the real combustion process. In addition, the large chamber volume and ignition position promote the heat transfer to the wall. Finally, the fuel conversion efficiency increases as the methane mol fraction decreases, and it is maximum when the stoichiometric ratio ranges from 0.8 to 0.9. These increases due to the composition and stoichiometric ratio could sufficiently compensate the decrease due to the specific heat ratio drop, LFG might be more advantageous than pure methane in a real engine.

• Journal of the Korean Geographical Society
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• v.47 no.5
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• pp.735-754
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• 2012

Korean society in the 2000 has experienced new many social and spatial issues such as the process of neoliberalism and changes in urban and spatial policies, the development of information and communication technology and reconfiguration of informational social space, radically increasing foreign immigrants and transformation to multicultural society, global warming and environmental injustice, and these new issues have promoted development of social geography in Korea. In addition to a review on them, this paper provides a review on empirical researches on traditional issues which have been dealt with in social geography in the 2000 in Korea. Even though there have been numerous sub-issues, they can be divided into two categories: one is urban and communal social geography including urban housing and residential segregation, urban social problems such as poverty, crime, education, health care, social welfare, urban and rural community building, identity, sense of place, and social movement; the other is social geography of population and migration, including population movement, aged society and social welfare for elderly people, and foreign immigrants and formation of multicultural social space. As some difficult conditions such as path-dependent process of neoliberalism, transformation toward informational, aged, and multicultural society would continue, so social geography in Korea to tackle with these external conditions should deepen its theoretical insights and widen its research issues.

• Journal of The Korean Association For Science Education
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• v.40 no.5
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• pp.531-542
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• 2020

The purpose of this study is to explore the research trend changes of convergence education since 2011 compared to the convergence education research that has been steadily continuing in science education. The trend in convergence education were investigated by comparing the number of publications, research subjects, research content, and topic linkages with previous studies, and using the network analysis method to check recent research trends. In the field of science education, the number of papers related to convergence education has been published more than 8.0% steadily, and it has been increasing since 2012, then decreasing again from 2015 and gradually increasing again from 2017. The subjects of study were high in elementary school students, while those in middle school, high school, and university students were low. While the number of in-service teachers increased, the number of pre-service teachers decreased, and the literature and public increased somewhat. In study content, effectiveness studies decreased, while development studies increased, and theoretical and perception studies appeared similar. In thematic linkage, the intra-science linkage was 23.9%, and the extra-science linkage was 76.1% and engineering/technology and art were high in extra-science linkage. In network analysis, elementary, science, STEAM, and program words have a high frequency of appearance and appear together with other words to lead the network. The educational implications of the research trend of convergence education will be more emphasized in the field of science education in the future, and in order to take root in the education field, research on secondary students should be more actively studied. In addition, it is necessary to move away from research on STEAM-centered program development and effects, and to increase research to establish the philosophical basis and theoretical of convergence education.

• Journal of the Ergonomics Society of Korea
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• v.35 no.4
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• pp.205-223
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• 2016

Objective:This study introduced the status of studies and the projects related with agricultural accident prevention carried out by the Rural Development Administration. This study was conducted to promote Korean farmers' agricultural safety activation by analyzing study trends on farmers' agricultural work safety. Background: Agriculture is one of the dangerous industries, and the agricultural accident rate is on the rise, due to recent serious aging and increased female work force. Such a phenomenon emerges as a serious problem from the social perspective, and therefore measures for farmers' healthy and safe agricultural activities and accident prevention are required. Method: This study conducted literature review related with domestic and international agricultural safety and health. This study also examined the hazard factors of agricultural labor and injuries, agricultural safety and health system and policy, support and education for farmers' safety practice, and the status of convenience tools and protection equipment, based on major study activities performed by the Rural Development Administration for recent four to five years. Results: Through the study results, the status of Korea's agricultural safety system, compensation support policy, safety education of farmers for actual practice, and diverse channels including media were confirmed. This study also presented the R&D implementation status on convenience equipment and protective gear to prevent agricultural diseases and safety accidents. Conclusion: This study found out that continuous monitoring and efforts are required to prevent accidents for the Korea's agricultural labor environment and agricultural safety, and that social bond of sympathy formation is demanded through effect analysis on the implemented projects including education and support projects. Furthermore, it can be understood that agricultural accident prevention should be carried out through shift from current government-led top down approach to bottom-up approach from itself. Application: The results of this study can be utilized as useful data for farmers' safety and health.

• The Journal of Fisheries Business Administration
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• v.24 no.1
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• pp.65-86
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• 1993

In this paper, fishery economics is reviewed to extend a basic opportunity for developing new fishery economics and to evaluate the effects of the import liberalization on the fish trade structure of Korea. The principle outline of extensions emphasis to realize the modern fishery problems based on fishery economics and develop the practical methodology in order to analyze the impacts of the import liberalization on the fishery and fishermen welfare. During the process of export - oriented industrilization, the role and position of fishery in the economy is changed dynamically. When faced with the imperative of the role and position of fishery in the economy, fishery economists and domestic policy makers must decide how to organize themselves for solving fishery problems under the new regime in the import liberalization on the fish trade. Fishery problems impacted by the new regime can not be solved by fishery itself but be solved by the centralized efforts of all contributors in national views. Therefore the new systematic analytical methodology must be develop and the traditional fishery economics must be related to the regional development strategy and fishery sociology as subsidiary theories specialized. Due to the impacts of the import liberalization on the fish trade structure, fishery economists face with radical changes in the domestic fishery : a place of the resources harvest to place of the combination resource harvest and its demand, a fishing as a resource exploitation to a fishing as a resource management, a traditional small scale costal fishing to a modernized and scaled fishing, fishery using the given natural resource itself to fishery as technology intensive industry, and a food supply industry to a welfare indusry based on the regional and economic resource and social environment. As these changes, fishery and its community's regional and economic resource and social environments as multiple roles of the regional economic development are emphasized in fishery economics under the new regime in the import liberalization on the fish trade. Furthermore, domestic policy makers and administrators in a public sector must realize the above radical changing trends in fishery and understand a social and economic environment in fishery and develop a new fishery structure focusing on the fishing system and the fishery laws. As this point, they make efforts to improve and develop fishery as a food supply industry. Japan, for example, has a non - governmental organization to conflict the problem of international fishery such as a movement of a civil environmental protection. Also fishermen in Japan already realized conservation and pollution problems in fishing as fundamental issues of human being.