• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.57-66
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• 2007

Natural gases generally consist of mainly $^{12}C$ and about 1.1% of $^{13}C$. It is well known that a stable carbon isotope, $^{13}C$, has been widely used for the applications of medical, pharmaceutical, and agricultural tracers. As a result, the development of the separation and concentrating technology of $^{13}C$ can cause of high value-added products and the possibility of the generation of new carbon materials, In general, there are two kinds of approaches to obtain a stable $^{13}C$ isotope by the separation of cryogenic distillation. One is to obtain a concentrated $^{13}CH_4$ isotope from natural gas. Another approach is to get concentrated $^{13}CO$ by distillation followed by a chemical reaction of $CH_4$ and $H_2O$. In this study, rigorous process simulations of the cryogenic distillation have been performed and analyzed for the concentrated separation of $^{13}C$ isotopes from LNG and NG by using commercial process simulator. Due to the very small differences of relative volatilities and separabilities of $^{12}C$ and $^{13}C$, the process design and operation of effective separation and concentration of $^{13}C$ need special strategies and feasibility studies. Utilization of vapor pressure data to acentric factor in SRK equation of state and optimized process conditions have been able to predict for the effective of the separation yield and concentration of $^{13}C$ for the cryogenic distillation. The various operation strategies for both batch and continuous cryogenic distillation are also studied and suggested for the basic design of the process. Development of this study can provide a tool for the effective design and operation of the cryogenic separation of $^{13}C$.

• Journal of Radiation Protection and Research
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• v.32 no.2
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• pp.89-96
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• 2007

Radiation safety managements in medical institutions are needed to protect certain radiation damages as a part of National Coalition. This study investigates the characteristics of self-efficacy that become the major factor on the knowledge, attitude, and behavior on the radiation safety management of radiation workers as an approach of educational aspects and analyzes the relationship between such factors to provide basic materials for improving the activity level of radiation safety managements. In order to implement the goal or this study, a survey was performed for 1,200 workers who were engaged in radiation treatments in medical centers, such as general hospital, university hospital, private hospital, and public health center for 42 days from July 23,2006. Then, the results of the analysis can be summarized as follows: 1. Average scores on knowledge, attitude, and behavior in the radiation safety management were presented as $75.76{\pm}11.20$, $90.55{\pm}8.59$, $80.58{\pm}11.70$, respectively. Also, the average score of self-efficacy was recorded as $73.55{\pm}9.82$. 2. Knowledge levels in the radiation safety management showed significant differences according to the sex, age, marriage, education, and experience. Also, males of married, older, highly educated, and largely experienced represented high knowledge levels. Attitude levels in the radiation safety management showed certain significant differences according to the type of medical centers in which private hospitals showed a relatively low level compared to that of high levels in university hospitals. Behavior levels in the radiation safety management also represented significant differences according to the age, marriage, education, experience, and types of medical centers. Factors in married, general hospital, older, highly educated, and largely experienced showed high behavior levels. In addition, the self-efficacy showed certain differences according to the marriage and types of medical centers. Factors in married and general hospital demonstrated high self-efficacy levels. 3. Relationship between knowledge, attitude, behavior, and self-efficacy on the radiation safety management showed statistical differences according to the relationship between the knowledge and the attitude, the knowledge and the behavior, the attitude and the behavior, the attitude and the self-efficacy, and the behavior and the self-efficacy. The relationship between the behavior and the self-efficacy was represented as r = 0.482, which was the strongest relationship in such factors. Also, the knowledge and self-efficacy didn't show certain relationships.

• Journal of Korean Home Economics Education Association
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• v.20 no.1
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• pp.137-152
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• 2008

This study examined the organization and operation of home economics curriculum of specialized middle school in the form of regular school among alternative schools and analyzed the perceptions of teachers and students about home economics class. Interviews were conducted with teachers of 6 specialized schools in order to determine the operations and teachers' perceptions of home economics education. Students' perceptions for home economics class were gathered through surveys with students from the 3 (of the original 6) schools that authorized the questionnaire survey. The final analysis utilized 205 student responses. Survey data were analyzed using the SPSS program. The results of the research were as follows: First, home economics education within specialized middle schools was mostly conducted according to the form of the technology-home economics curriculum, which is the national common basic curriculum. Compared to the 7th national curriculum, the class of technology-home economics curriculum in 4 schools occurred 1 hour less each week. Each school incorporated various specialized curricula related to home economics. Second, as for the operation of home economics education in specialized schools, most home economics classes were conducted by teachers who had majored (or minored) in home economics. Moreover, all but 1 school, which used self-made materials, used the national textbook and dealt with the entire content of the textbook. For teaching-learning methods and instructional media, various means were utilized. For evaluation methods, most schools based grades on paper-and-pencil tests(50-60%) and performance tests(40-50%). Third, among teachers' perceptions of home economics education, the meaning of home economics education was focused on practical help and the pursuit of home happiness; the purpose was to realize the happiness of students and their homes by applying these to actual living, and increase students' ability to see the world. In regards to difficulties in educational operations, most pointed out poor conditions of practice rooms. As for differences from general schools, most teachers mentioned the active communication with students. Fourth, through the home economics class, it was found that students perceived the goal of technology-home economics curricula as lower than average. Among students' perceptions about home economics class, most were negative. Perceptions about goal of technology-home economics curricula and home economics class also showed meaningful differences according to each school. Students of the school, which had more home economics class hours and specialized curricula related to home economics, perceived more positively. Also, students who were more satisfied with school and learned from a teacher who majored in home economics tended to perceive home economics class more positively.

• Journal of Korean Home Economics Education Association
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• v.32 no.1
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• pp.15-34
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• 2020

The purpose of this study was to examine the secondary school technology and home economics teachers' perception of the school curriculum organization and high school credit system. For this purpose, the questionnaire data of 345 secondary technology and home economics teachers nationwide were analyzed through descriptive statistics, t-test, and F-test with SPSS 24. The research results were as follows. First, technology and home economics teachers recognized that current schools lacked the time to organize technology and home economics curriculum (61.1%) and the number of teachers (53%). Most of them have participated (62.0%) and were very willing to participate in the school curriculum organization (4.47, 89.9%). Second, technology and home economics teachers were aware of the high school credit system more than the average (3.34), and more negative (52.8%) than positive (37.7%). As a positive influence, students recognized career choices (3.88) and deepened professional content in their major fields (3.81). On the other hand, the negative impact was the decrease in choice due to non-entry subjects (3.90) and the difficulty in moving teachers to school (3.57). Third, in order to stably respond to the introduction of high school credit system, technology and home economics teachers recognized the importance of coordinating career elective courses (4.51), developing and disseminating teaching and learning materials for elective courses (4.46), separating technology and home economics (4.45), and providing training on evaluation methods and applications (4.44). This study would be useful to provide the basic information and data for the future development of technology and home economics curriculum at the national level based on high school credit system.

• Journal of Korean Home Economics Education Association
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• v.31 no.1
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• pp.115-136
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• 2019

The purpose of this study is to analyze the contents of 'housing' unit in middle school Technology-Home Economics textbooks according to the 2015 revision curriculum based on the targets of SDGs. All contents of the ten textbooks of five publishers, such as texts, photographs/figures/tables, activity tasks, and supplementary materials were analyzed in terms of SDGs targets. The number of 'housing' contents among 4 small housing units of Technology-Home Economics book 1 & 2 varied from 64 to 97 by publishers. Beside SDGs4.7, which contains inclusive and general ESDGs, 24 targets of 10 SDGs were found to be related to the contents of 'housing' and were grouped into 15 target categories. The number of SDGs target categories related to housing contents of each small unit and total of all units differed by publishers. Each of 4 small 'housing' units from all the five publishers was related to 6~10 target categories. The contents of five book 1's were related to smaller number of target categories than those of five book 2's. They corresponded to 9 and 12 target categories, consecutively. Only SDGs' target11.1 (appropriate and safe housing and basic services) was related to all the four small units of 'housing' contents among all the five publishers. covering 43.8% of the housing contents. In conclusion, the contents of the 'housing' unit were related to broad range of SDGs targets. Further study could relate goals of teaching-learning plan to various global targets of SDGs according to the contents of 'housing' in order to accomplish ESDGs.

• 대한공업교육학회지
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• v.44 no.2
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• pp.28-46
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• 2019

The purpose of this study is to use as a basic data of establishing operating Course-based National Technical Qualification(CNTQ) support program by examining the educational needs for operating CNTQ of vocational school teachers, and to contribute to the vocational school settlement of CNTQ course. To achieve those purposes, this study drew 27 tasks performed by teachers operating CNTQ. Also, it surveyed the perceived importance and the performance. The findings of this study are as follows. First, it is showed that 'selection of qualification fields and confirmation of organization criteria, organization of educational training time by competency unit, organization of subjects and establishment of competency unit operating plan by grade and semester, selection of teaching materials, implementation of education and training, establishment of evaluation plan, implementation of evaluation, re-education and re-evaluation students with grades under 40%, guidance of paper evaluation, guidance of practical evaluation, guidance of interview evaluation' are the first priority tasks in the result of the need analysis. Second, it is indicated that 'application of external evaluation, guidance to retake an exam for failure' are the secondary priority tasks. According to these results, the following conclusions were made. First, it will be more positive effects if the educational needs in the next CNTQ support program include contents of the first priority tasks. Second, it is indicated that the priority of the educational needs for tasks of operating plan stages is commonly high. In particular, the highest ranking in the result means that it is completely supported from the first step on operating course. It is expected that the program which teachers on operating the course of similar qualification fields share each operating experience is effective. Third, the priority of the educational needs for external evaluation step ranked high. External evaluation has a different level of difficulty and a form of practical evaluation output according to qualification fields, so the method of guidance has to be different. It needs the program constructed by similar fields.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.4
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• pp.15-26
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• 2015

The Daegu Metropolitan Transit Corporation Advisory Committee has chosen 5 styles of bridge-pier designs, including coating, graphic, planting, billboard and safety-facility style, based on the results of landscape simulations from a previous study. This study was conducted to investigate citizen's preferences and emotional images for each style of bridge-pier design, by aiming at the pilot urban landscape improvement section from Daebong Bridge in Suseong Gu to the crossroads near Dongseong Elementary School in Daegu Metropolitan City. The questionnaire was drawn up regarding the urban landscape improvement plans applied to the research area, and the questions were about citizens' perception of bridge-pier structures generated by constructing a light rail transit, important factors to consider when designing bridge piers, preferences for each style of bridge-pier design and emotional impact. 60.4% of the survey participants were found to perceive bridge-pier structures as unattractive, so it was necessary to improve them aesthetically. Regarding visual factors of bridge-pier designs, color was most important at 5.81, followed by form at 5.57. Regarding aesthetic component factors, harmony was most important at 6.07, followed by amenity at 6.00. In the survey participants' preference for each bridge-pier design, the graphic style was preferred most at 4.14, followed by the planting style. In emotional adjectives used for each bridge-pier design, the coating style, the safety-facility style and the non-treatment style showed similar results, and all of these styles were evaluated as artificial, lifeless and desolate. The graphic style and the billboard style showed different tendencies, depending on visual factors and aesthetic component factors applied to the graphic design used for these two bridge-pier styles. Since natural materials were used for the planting style, however, it showed high preference for such emotional images as natural and lively. The emotional adjective 'amiable' was found to affect citizens' preferences for each bridge-pier aesthetic improvement plan most, and it was also analyzed to have an effect on all the styles of bridge-pier designs. To improve the landscape of a light rail transit being constructed inside the urban area, this study quantitatively extracted citizens' preferences and emotional adjective for every style of bridge-pier design applied to the pilot urban landscape improvement section, and it is expected that the results of this study will be used as basic data to improve the landscape of bridge piers.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.33-40
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• 2014

The purpose of this study is to examine vegetation of the outer walls of the Jeongyi Town Wall in Jeju and analyze the characteristics and problems identified, for suggesting preliminary data for selecting species of plants appropriate for the greening of the walls in the southern temperate climate region, including Jeju. The result of this study is as follows. The number of plants growing naturally around the walls of the town was identified to be 52 taxa. Based on the list of naturalized plants, there are 5 taxa; Sonchus oleraceus, Houttuynia cordata, Crassocephalum crepidioides, Erigeron annuus and Lamium purpureum. The number of species by district was from 3 to 14 taxa with 7.1 taxa on average. Analyzing by the constancy class, plants in class III included Sedum bulbiferum, Trichosanthes kirilowii, Hedera rhombea and Boehmeria nivea. Manipulation of the species composition table shows that the number of plant species growing naturally around the walls of Jeongyi Town Wall is a total of 52 taxa, including 11 taxa by differential species of community and 41 taxa by companion species. The types of plants very useful for the covering of the walls are evergreen climbing vine, such as Hedera rhombea, Ficus thunbergii and Euonymus fortunei and deciduous climbing vine, such as Parthenocissus tricuspidata, Trichosanthes kirilowii and Paederia scandens. In addition, Ficus stipulata is identified as a vegetation more appropriate for the southern-ward lattice-blocked walls. Woody plants, such as Akebia quinata, Celastrus flagellaris, Ampelopsis brevipedunculata for. citrulloides, Rubus hirsutus, Clematis apiifolia and herbaceous plants, such as Dioscorea tenuipes, D. quinqueloba, D. nipponica, Cayatia japonica and Paederia scandens var. angustifolia are highly useful materials for climbing plants for covering the walls of the southern province. Pteridophyte, such as Lemmaphyllum microphyllum, Pteris multifida, Cyrtomium falcatum and Lygodium japonicumare suggested as very useful for increasing unique regional characteristics of the southern province, including Jeju.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.126-136
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• 2017

Gardeners have a desire to not only enjoy a garden but to create the garden themselves and play the role of garden designer. However, they express a great difficulty in gardening activities such as planting and managing plants, the main materials of the garden, due to lack of expertise. Therefore, in order to encourage hobby gardening activities, it is necessary to understand the preferences of the gardeners so that they can easily experience and create a garden, and to provide information on gardening know-how and preferred plants according to places given high preference. This study analyzed the preference for places and plants characteristics according to the purpose of creating a garden. To this end, a questionnaire survey was conducted with visitors to the Korea Landscape and Garden Expo, expected to have been attended primarily by gardening enthusiasts. As a result, gardeners were divided into three groups: appraisal - purposed type, multifunctional type, and participation - purposed type. The group of appraisal purposed type preferred porches and terraces, and private home front yards as well as favored indoor places rather than outdoor places compared with other types. In selecting plants, they prefer plants that can be easily managed in an indoor environment and appreciate natural colors through the colors of flowers and leaves. The multifunctional type group preferred a private home front yard as a garden creation space. Compared with the other types, it showed a high preference for 'unoccupied land in urban housing' and 'community garden' and was analyzed as a group having a high understanding of garden activities. In selecting plants, this group preferred fruit trees or productive plants such as homegrown crops. The participation purposed type group preferred porches and terraces as well as private home front yards as a gardening space. For plants, they preferred plants that are easy to manage. It is meaningful that this study provided preferences for places and plant characteristics according to the creative purpose of the gardener and provided basic data for selecting the place and the plant characteristics of the garden according to the gardener's type.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.290-299
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• 2011

Objectives: The usage of fluoride varnish for a moderate to low caries-risk group has not been well validated. This study aimed to evaluate the preventive and therapeutic efficacies of fluoride varnish on the initiated root caries. Materials and Methods: Ten premolars were sectioned into quarters, further divided into two windows, one of which was painted with Fluor Protector (1,000 ppm fluoride, Ivoclar Vivadent). An initial lesion with a well-preserved surface layer was produced by pH cycling. Scanned line analysis using energy dispersive spectrometry determined the weight percentages of Ca and P in the demineralized layer. Scanning Electron microscopy and confocal laser scanning microscopy (CLSM) evaluated the varnish-applied root surfaces. Results: The mean lesion depth (SD) was 12.3 (2.6) ${\mu}m$ (single cycling) and 19.6 (3.8) ${\mu}m$ (double cycling). Double cycling extended the lesion depth, but induced no more mineral loss than single cycling (p < 0.05). The mean weight percentages of Ca and P between groups with and without varnish were not significantly different (p < 0.05). A CLSM showed varnish remained within 15 ${\mu}m$ of the surface layer. Conclusions: When a mild acid challenge initiated root tissue demineralization, the application of low-concentration fluoride varnish did not influence the lesion depth or the mineral composition of the subsurface lesion.