• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1560-1569
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• 2022

Liquid fueled molten salt reactors (MSRs) have seen renewed interest because of their inherent safety features, higher thermal efficiency and potential for efficient thorium utilisation for power generation. Thorium fluoride is one of the salts used in liquid fueled MSRs employing Th-U cycle. In the present study, ThF₄ was prepared by hydro-fluorination of ThO₂ using anhydrous HF gas. Process parameters viz. bed depth, hydrofluorination time and hydrofluorination temperature, were optimized for the preparation of ThF₄ in a static bed reactor setup. The products were characterized with X-Ray diffraction and experimental conditions for complete conversion to ThF₄ were established which also corroborated with the yield values. Hydrofluorination of ThO₂ at 450 ℃ for half an hour at a bed depth of 6 mm gave the best result, with a yield of about 99.36% ThF₄. No unconverted oxide or any other impurity was observed. Rietveld refinement was performed on the XRD data of this ThF₄, and Chi2 value of 3.54 indicated good agreement between observed and calculated profiles.

• Journal of Biosystems Engineering
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• v.5 no.1
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• pp.58-65
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• 1980

Sinkage differences between the wheels of a transplanter which are caused by the different hard pan of fields and land preparation affect the field performance of a rice transplanter. In this experiment the relationships between the sinkage differences of the wheels of a transplanter and the planting distance, planting angle, planting depth and deviation from a straight transplanting line were investigated. The objective of this experiment was to obtain some basic informations for the effective use of the rice transplanter . The results of this experiment are as follows. 1. Transplanting distance became shorter as the sinkage differences increased. This effect was greater on the side of the transplanter with a shallower sinkage. 2. The depth of transplanting increased as the differences in the depth of sinkage increase for the side with the deeper sinkage. An opposite trend was observed for the side with shallower sinkage. 3. The angle of transplanted seedlings from the vertical portion increased slightly as the sinkage differences increased. The variation in results were greater from the side of the transplanter with deeper sinkage than with shallower sinkage. 5. The best postures of planted seedling were found when the water depth was 3 cm for the side of transplanter with deeper sinkage and 4 cm for the shallower sinkage side. The relationships between the postures of planted seedling and water depth. , or $y=67.62 + 10.69x-1.76x^2$ for the side of transplanter with deeper sinkage and $y=66.64+11.62x-1.50x^2$ for the side with shallower sinkage, were found from this experiment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.636-641
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• 2002

Optimum extraction condition and clarification process were investigated to manufacture liquid extract tea using Phellinus linteus. Carbohydrates content in the raw Phellinus linteus was 80.9%. Major minerals were K, Ca, Fe and Na, but vitamin B$_1$, B$_2$, and C were not detected. The best extraction condition was 5% raw material at 10$0^{\circ}C$ within 3 hr. To clarify the extract, three methods of filtration with depth filter pad, centrifugation and addition of several filter aids were studied. Filtration with depth filter pad and centrifugation were highly effective on the clarification and the changes in the turbidity for 7 weeks at 4$0^{\circ}C$ were not occurred. The optimum clarification condition was centrifugation above 6,000 rpm or filtration with 8 ${\mu}{\textrm}{m}$ depth filter pad.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.249-258
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• 2020

The purpose of this study provides multicultural adolescents' out of school career preparation experience. Seven multicultural adolescents out of school living in Seoul, Gyeonggido, Chungchungdo were selected for the in-depth interview. Data were collected from July to September, 2019. This research utilized Colaizzi's phenomenological method. The participants provided 14 themes on the essential structure of experience and 5 theme clusters. The final 14 themes were relationship with friends, speedy learning ability, fear of learning, generous character, no dreaming, enjoying hobby, influence of job, influence of mother, no concept of career, looking for mother language-related job, no managing time and health, material abundance, trying diet, burden about test. Based on this result, it is suggested to acknowledge importance of positive motive pursuit for career, various support giving power, positive attitude of career, self-reflection, road to go for career preparation.

• Applied Microscopy
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• v.42 no.1
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• pp.49-52
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• 2012

For TEM study of biological samples or polymers that are contained in organic structure, it is often required that the sample is prepared by using ultramicrotome and stained with proper agents to increase the contrast of organic structure. In this study, we investigated an efficient TEM sample preparation method for ductile heterogeneity material by using ultramicrotomy. Cryo-ultramicrotomy is a suitable method that is capable of rendering sample hardness for various ductile materials. However, it has several factors to consider, such as experimental cost, working time and finding the optimal staining conditions. To satisfy these considerations, we prepared TEM sample by using ultramicrotome without cryofunction, and secured the sample hardness by applying the staining process prior to ultrathin sectioning. The cross-linked polyethylene structure in the sample was stained with the 2% $RuO_4$ solution in a sealed test tube for 24 hours at $4^{\circ}C$. After the sample staining, ultrathin sections of sample were prepared using ultramicrotome. As a result, it was revealed that the difficulties associated with staining of ultrathin sections prepared by low-temperature conditions were improved. In addition, appropriate staining depth of sample could be selected for sectioning process. The quality of TEM sample obtained by using this method was better than that of cryo-ultramicroscopy. Finally, it is expected that our method could be effectively applied in TEM sample preparation for a variety of nano-bio convergence materials.

• Journal of agricultural medicine and community health
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• v.43 no.2
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• pp.63-73
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• 2018

Objectives: The purpose of this study was to review the disaster preparation and response programs and the status of disaster preparation in public health center. Methods: In depth interview was performed in September 2017 using 5 open questions to the persons who are in charge of disaster response services in 5 public health centers of different levels in Korea. The questions included general characteristics of public health center, disaster programs and future issues. The research hired a quality method. Results: In general, the persons in charge recognized the cooperative agency of local government in disaster management. There were no disaster preparation programs developed by the public health centers. Most of the preparation were passive activities such as emergency support, crisis management on communicable disease and quarantine, participation in biological disaster response training, and education etc. The persons in charge emphasized necessity of disaster preparation programs. Conclusions: Disaster preparation and responsiveness is an evolving issue in public health centers in Korea. Medical support system and communicable disease management system are being set up in the national level. A comprehensive system covering health management, nutritional support, mental health, environment management of shelter, and volunteers supports on public health center level needs to be developed along with a easy-to-follow manual.

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.2.1-2.10
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• 2018

Objectives: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). Materials and Methods: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. Results: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). Conclusions: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.45-56
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• 2015

The distribution of seaweed was examined in Jeonnam archipelago marine ranching area, the coastal of geumo-do, Yosu. Abundance and distribution of seaweed in dropping site of artificial reef were sampled at 6 station at October 2007. Seaweed community were investigated with quadrat method at line-transect by scientific SCUBA divers. as a result, 30 species in total, 4 green, 9 brown and 15 red seaweed were identified. Range of seaweed biomass in all sampling stations were about 1,600~4,000 g/m². At intertidal zone, appearance of individuals and dominance rate were showed higher than below the subtidal line and at depth from 4m to 6m, individuals, dominance rate and biomass were represented low level. characteristic of water in marine ranching area is turbidity and also compensation depth is low. For that reason, individuals of seaweed community were smaller from depth of 4 meters. Therefore, when equip the artificial reef for preparation of seaweed beds need consider that equipment periods(early spring; before releasing marine seaweed spore) and suitable water depth(3~6m).

• Korean Journal of Human Ecology
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• v.20 no.1
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• pp.119-132
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• 2011

The purpose of this study was to explore the parenting experiences of mothers of disabled children. The study focused on how mothers of disabled children prepared for their children's transition to elementary school and how they experienced their children's adjustment to school. Twenty mothers of children with developmental or intellectual disabilities participated in the study. Each mother had experienced an inclusive education program at an elementary school for more than a year. Twelve mothers have children with intellectual disabilities and eight have children with developmental disabilities. Individual in-depth interviews were carried out to collect qualitative data. To analyze the data, the research followed the phenomenological analysis method of Giorgi. The results showed that mothers of disabled children were actively involved with inclusive day care centers and therapy programs to prepare for children elementary school. Most wished to send their children to a general elementary school with an inclusive program, although decision making was not easy. When their children entered elementary school, some mothers observed their children's struggle with school and their peer relationships. They sought support from teachers and other mothers. These mothers showed a desire for their children's social independence. This study highlighted the necessity to develop support programs for disabled children and their mothers.

• The Korean Journal of Elementary Counseling
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• v.7 no.1
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• pp.135-163
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• 2008

This study intends to confirm if it is effective in improving the problem behaviors by applying "Logical Consequence" suggested by Adler to the class management. The researcher who is in charge of the 4th grade class of elementary school in G city applied Adlerian logical consequence to her children, observed and examined the effectiveness of reducing the problem behaviors by the qualitative study method of in-depth interview from March to October. The problem behaviors treated in this study includes irrelevant remarks and gossip in school time, no preparation for taking lessons in time, no preparation of a textbook and a supply, no involvement in doing homework, scribbling and poor handwriting on a textbook, teasing a friend (abusive language, joking, violence), indoor running, no involvement in doing a task, being late and no arrangement of indoor shoes. In conclusion, this study indicated that the use of Logical Consequence was relatively effective in improving the problem behaviors and more effective in individual behaviors rather than group's behaviors. While the problem behaviors conducted in a class in the daily routine were effective at the point of the occurred problems, the problem behaviors occurred at the point of time related to a home or the finish of daily routine were ineffective.