• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.4
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• pp.221-226
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• 2020

This experiment was conducted to compare the seed productivity of the Italian ryegrass(Lolium multiflorum Lam.) varieties sown in the spring in Gangwon region. The experiment was randomized block design with three replications. The Experimental field was located in alpine areas of about 600 m above sea level in Gangwon province. The tested Italian Ryegrass varieties were 'Greenfarm', 'Greencall' and 'Kowinearly' developed by National Institute of Animal Science, RDA. Italian Ryegrass varieties were sown on March 26, 2020, and the harvest was on the 60th day of mean heading date, July 2. The heading date of Kowinearly was May 8, but Greenfarm and Greencall was May 4. The plant length was the largest in the Kowinearly variety. However, the Kowinearly suffered severe lodging. There was no significant difference in the length of spike among varieties, and the number of seeds per spike was the lowest in Greenfarm at 118.5 seed/spike. As for the seed weight per spike, the Greenfarm variety was significantly lower at 0.56 g/spike, but the 1,000 seed weight was the heaviest in the Greenfarm at 2.5g.. The number of spike per unit area was the highest in Greenfarm at 906/㎡. The dry matter content of seeds was the highest in Greenfarm at 54.3%, and for straw, Kowinearly was the highest at 35.3%. Seed productivity was not significant among varieties, and the average was 1,493 kg/ha. The yield of straw after seed production was also not significant among varieties (P>0.05), and the average was 3,172 kg/ha. From the above results, the production of Italian ryegrass seeds through spring sowing in the Gangwon region is not much than autumn seeding, requiring the input of various technologies to increase productivity in the future, and it is desirable to determine the production cost through economic analysis was judged.

• Composites Research
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• v.34 no.3
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• pp.192-198
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• 2021

Due to enormous market growing of electric vehicles without combustion engine, reducing unwanted BSR (buzz, squeak, and rattle) noise is highly demanded for vehicle quality and performance. Particularly, innerbelt weatherstrips which not only block wind noise, rain, and dust from outside, but also reduce noise and vibration of door glass and vehicle are required to exhibit high damping properties for improved BSR performance of the vehicle. Thermoplastic elastomers (TPEs), which can be recycled and have lighter weight than thermoset elastomers, are receiving much attention for weatherstrip material, but TPEs exhibit low material damping and compression set causing frictional noise and vibration between the door glass and the weatherstrip. In this study, high damping EPDM (ethylene-propylene-diene monomer)/PP (polypropylene) thermoplastic vulcanizates (TPV) were investigated by varying EPDM/PP ratio and ENB (ethylidene norbornene) fraction in EPDM. Viscoelastic properties of TPV materials were characterized by assuming that the material damping is directly related to the viscoelasticity. The optimum material damping factor (tanδ peak 0.611) was achieved with low PP ratio (14 wt%) and high ENB fraction (8.9 wt%), which was increased by 140% compared to the reference (tanδ 0.254). The improved damping is believed due to high fraction of flexible EPDM chains and higher interfacial slippage area of EPDM particles generated by increasing ENB fraction in EPDM. The stick-slip test was conducted to characterize frictional noise and vibration of the TPV weatherstrip. With improved TPV material damping, the acceleration peak of frictional vibration decreased by about 57.9%. This finding can not only improve BSR performance of electric vehicles by designing material damping of weatherstrips but also contribute to various structural applications such as urban air mobility or aircrafts, which require lightweight and high damping properties.

• Korean Journal of Culture and Social Issue
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• v.26 no.3
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• pp.121-143
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• 2020

The present study examined the content and changes in leader role schemas associated with 'male' leaders, 'female' leaders, and 'good' leaders over the past 10 years in Korea. In addition, we analyzed how the gender of the respondents affects their perception of male leaders versus female leaders as a good leader. A total of 736 Korean adults residing in the Seoul metropolitan area participated in the survey at two different time points, one in 2007, and the other in 2017. The respondents were presented with a total of 90 behavior items driven from the literature and asked to choose the items that represent male leaders, female leaders, and good leaders, respectively. We found that the chosen behavior items for male leaders versus female leaders matched closely to the typical sex role of males (i.e., being agentic) versus females (i.e., being communal). By contrast, the chosen behavior items for good leaders reflected both the male-typed roles and the female-typed roles. We also found that the role schemas associated with male leaders as well as good leaders have changed over the 10 year period. Those schemas also differed between male versus female respondents. For female leaders, however, the role schemas were found to be stable over the 10 years. We also found that the good leader schemas are more specified and variable than are the male or the female schemas. Additionally, in the 2007 survey male characteristics overlapped with good leader characteristics to a greater degree than did female characteristics. This difference was no longer observed in the 2017 survey. The observed difference in the degree of overlap between male (versus female) characteristics with good leader characteristics was attributable to the perceptions of male respondents. We discuss implications of our findings and directions for future research.

• Resources Recycling
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• v.31 no.4
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• pp.56-65
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• 2022

Copper is one of the non-ferrous metals used in the electrical/electronic manufacturing industries due to its superior properties particularly the high conductivity and less resistivity. The effluent generated from the surface finishing process of these industries contains higher copper content which gets discharged in to water bodies directly or indirectly. This causes severe environmental pollution and also results in loss of an important valuable metal. To overcome this issue, continuous R & D activities are going on across the globe in adsorption area with the purpose of finding an efficient, low cost and ecofriendly adsorbent. In view of the above, present investigation was made to compare the performance of a plant root (Datura root powder) as a bio-adsorbent to that of the synthetic one (Tulsion T-42) for copper adsorption from such effluent. Experiments were carried out in batch studies to optimize parameters such as adsorbent dose, contact time, pH, feed concentration, etc. Results of the batch experiments indicate that 0.2 g of Datura root powder and 0.1 g of Tulsion T-42 showed 95% copper adsorption from an initial feed/solution of 100 ppm Cu at pH 4 in contact time of 15 and 30 min, respectively. Adsorption data for both the adsorbents were fitted well to the Freundlich isotherm. Experimental results were also validated with the kinetic model, which showed that the adsorption of copper followed pseudo-second order rate expression for the both adsorbents. Overall result demonstrates that the bio-adsorbent tested has a potential applicability for metal recovery from the waste solutions/effluents of metal finishing units. In view of the requirements of commercial viability and minimal environmental damage there from, Datura root powder being an effective material for metal uptake, may prove to be a feasible adsorbent for copper recovery after the necessary scale-up studies.

• The Korean Journal of Archival Studies
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• no.74
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• pp.45-78
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• 2022

South Africa implemented apartheid from 1948 to 1994. The main content of this policy was to classify races such as whites, Indians, mixed-race people, and blacks, and to limit all social activities, including residence, personal property ownership, and economic activities, depending on the class. All races except white people were discriminated against and suppressed for having different skin colors. South African citizens resisted the government's indiscriminate violence, and public opinion criticizing them expanded beyond the local community to various parts of the world. One of the things that made this possible was photographs detailing the scene of the violence. Foreign journalists who captured popular oppression as well as photographers from South Africa were immersed in recording the lives of those who were marginalized and suffered on an individual level. If they had not been willing to inform the reality and did not actually record it as a photo, many people would not have known the horrors of the situation caused by racial discrimination. Therefore, this paper focuses on Rise and Fall of Apartheid: Photography and the Bureau of Everyday Life, which captures various aspects of apartheid and displays related records, and examines the aspects of racism committed in South Africa described in the photo. The exhibition covers the period from 1948 when apartheid began until 1995, when Nelson Mandela was elected president and the Truth and Reconciliation Commission was launched to correct the wrong view of history. Many of the photos on display were taken by Peter Magubane, Ian Berry, David Goldblatt, and Santu Mofoken, a collection of museums, art galleries and media, including various archives. The photographs on display are primarily the work of photographers. It is both a photographic work and a media that proves South Africa's past since the 1960s, but it has been mainly dealt with in the field of photography and art history rather than from a historical or archival point of view. However, the photos have characteristics as records, and the contextual information contained in them is characterized by being able to look back on history from various perspectives. Therefore, it is very important to expand in the previously studied area to examine the time from various perspectives and interpret it anew. The photographs presented in the exhibition prove and describe events and people that are not included in South Africa's official records. This is significant in that it incorporates socially marginalized people and events into historical gaps through ordinary people's memories and personal records, and is reproduced in various media to strengthen and spread the context of record production.

• Korean small business review
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• v.42 no.2
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• pp.69-92
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• 2020

This study is aimed at the growth and development of family businesses that greatly contribute to Korea's economic development, but the specific research purpose is to firstly examine the research trends and current status of Korean family businesses and compare them with those of developed countries such as the United States. Second, I would like to look at the future research for revitalizing Korean family business research. In addition, we intend to contribute to increasing the interest in this field and the number of researchers involved. The research target of this paper is 212 papers published in professional academic journals for 13 years from 2006 to 2018 when family businesses began to be fully researched in Korea, 112 master's and doctoral dissertations (graduate schools), and 324 totals. As a result of empirical analysis, the number of published papers is increasing more than the initial ones, but it has been on the decline recently. In addition, 57.5% of the journals are papers that do not have specific definitions or simply list the claims of several scholars by analyzing content. Thesis was 33.9%. As for the type of research, qualitative research, which is a conceptual research, is a small number, and empirical research occupies most of the research topics. Research topics and academic dissertations also have a large proportion of management, management strategy, succession, financial accounting, and business performance. In other words, it can be said that the research on family business in Korea corresponds to the early childhood of the United States. First of all, in the future, we need to put more effort into increasing the qualitative research, starting with the definition of a family business, which is an essential problem, in addition to the theory building of family business. Second, as an analysis level of research, we should make family an important level of analysis for existing individuals, groups, and organizations. Third, the research subject and research area should be expanded. It is desperately necessary to study large companies including chaebols, mainly from small and medium-sized companies, which are the existing research areas of family business. In addition, it is considered that it is necessary to appropriately introduce various theories suitable for the interdisciplinary study, which is the characteristic of the family business, for example, theories of family science, psychology, and sociology. Fourth, it should build the research infrastructure.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.4
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• pp.18-29
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• 2022

Five species of plants (Clerodendrum trichotomum Thunb., Angelica dahurica (Fisch. ex Hoffm.) Benth. & Hook. f. ex Franch. & Sav., Caryopteris incana (Thunb. ex Houtt.) Miq., Lonicera japonica Thunb., and Parasenecio auriculatus var. matsumurana Nakai) native to the clean area of Mt. Jiri were selected. The collection period was from May to September 2021, and the five species plants were collected in their native habitats with flowers in full bloom. The collected plants were extracted with 70% EtOH, and 17 kinds of polyphenol components were analyzed. Next, flowers, leaves, stems, and roots were separated from plants, extracted with 70% EtOH for each part and experiments were conducted on DPPH, ABTS, total polyphenols, and total flavonoids. The results are as follows. 1. It was found that there were a total of 8 kinds of polyphenols contained in 5 species of plants that are native to Mt. Jiri. Among the polyphenol components, chlorogenic acid was contained in 4 species of plants, and caffeic acid was contained in 2 species of plants. 2. As a result, the DPPH radical scavenging activity was the best in the stem of P. auriculata and the C. trichotomum was good regardless of the specific part. It was found that the activity-scavenging activity was good in the flowers of A. dahurica and the leaves of L. japonica. 3. The highest ABTS radical scavenging activity was C. trichotomum Thunb., whose EC₅₀ value was 38.73~66.28ppm. Next, the leaves and stems of L. japonica Thunb., A. dahurica and P. auriculata, and the leaves and stems of C. incana appeared in that order. 4. The highest total polyphenol content was 154.83mg GAE/g in the leaves of C. trichotomum, followed by about 130mg GAE/g in the flowers of C. trichotomum and P. auriculata. The lowest was 26.27mg GAE/g in the stems of A. dahurica.

• Journal of the International Relations & Interdisciplinary Education
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• v.2 no.1
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• pp.57-82
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• 2022

This study aims to investigate and analyze the perception of communication capability which is one of the sub-competencies of NCS vocational substructure basic competence, and then seek the direction of prospective courses. To do this, the researcher conducts a non-face-to-face survey by creating five questions under the following five categories: The importance and necessity of communicative competence, students and educators of communicative competence classes, contents and methods of curriculum and teaching and learning, communicative competence and writing skills and operation of extracurricular programs. This researcher has been teaching basic education even before the communication skills curriculum was created in college, now, in a situation where communication skills have become selective education, it is intended to grasp the perception of college students about communication skills for first graders. This study attempted to analyze the survey area in more depth through group FGI after conducting an online survey by dividing it into several items. As a result, students felt that communication skills became motktkre important through COVID-19. Among the bottom five communication skills, speaking skills were found to be the most important, reading ability was recognized as the least important. On the other hand, there was a strong hope to know about the level of communication ability, type of communication, and method of communication about oneself. In addition, they recognized that communication skills should be learned in their first year of college, and hoped to be operated at all times as a non-disciplinary program. In particular, in the bottom five areas of communication skills, the expectations and actual hopes for speaking skills were the highest compared to the rest, and in terms of teaching and learning methods, they wanted to improve their skills through feedback and practice rather than theory. These research results have great implications for setting the direction of operation of classes, such as the content and method of classes in communication skills, in the future.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.2
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• pp.210-223
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• 2023

This study developed elementary and middle school career education programs linked to science subjects and local natural resources, and explored learning effects and implications for developing and operating career programs. In order to achieve the research purpose, a 10-hour career education program using local natural and social resources was developed and applied to 25 elementary and middle school students in rural areas. As a result of the study, most of the elementary and middle school students who participated in this study were not well aware of the natural and social resource value of the area where they lived. Therefore, when developing and operating a regional-based career education program for elementary and middle school students in rural areas, it is necessary to operate a separate teaching/learning activity time so that students can fully know the natural and social information and resource values of the region. In addition, in order to enhance students' participation and interest in career education programs, it is necessary to organize the operation of the program in groups, not individuals, and to guide students in detail by dividing the program's performance process into several sub-steps. Finally, the core material of regional-linked career education-related programs focused more on their own content, that is, agricultural products grown by parents, and future job settings were higher in start-ups that directly operate companies such as travel agencies and manufacturing companies. Given the recent emphasis on career education in the curriculum, it is suggested that local students should pay more attention to finding materials with local resource value in the field of geoscience, which is closely related to natural resources, and developing and operating them as career education programs linked to local resources.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.122-131
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• 2023

This study was aimed to determine the effects of grow media on the mineral contents of the leaves and growth characteristics of strawberry grown under aquaponics system in a plant factory. For aquaculture, 12 fish (Cyprinus carpio) (total weight, 2.0 kg) were raised in an aquaponics tank (W 0.7 m × L 1.5 m × H 0.45 m, 472.5 L) filled with 367.5 L of water at a density of 5.44 kg·m^-3 and total 34 of strawberry seedlings were transplanted in the pots filed with 200 g of orchid stone, hydroball or polyurethane sponge in the growing bed (W 0.7 m × L 1.5 m × H 0.22 m) laid out with holly acrylic sheet (140×60 mm, Ø80) on the top of the system. The pH and EC of the aquaponic solution was ranged from 7.6 to 4.9 and 0.24-0.91 dS·m^-1, respectively. The concentration of NO_3-N was about 28% lower than that of the hydroponic standard solution, and K, Fe and B were 10, 27 and 3.8 times lower, respectively; however, the mineral contents of strawberry leaves were in the appropriate ranges with lower contents in the leaves grown with sponge media. The organic content (OM), nitrogen (N), phosphorus (P), and potassium (K) of the sludge were 61.5, 5.72, 8.92, and 0.24%, respectively. The leaf area, leaf number, and dry and fresh weights of shoot at 81 DAT were significantly higher in the hydroball, and the average number of fruits per plant was significantly higher in both the orchid stone and hydroball. There was no significant difference in the fresh and dry weights of fruits. Integrated all the results suggest that the orchid stone and hydroball media are more effective to utilize nutrients in solid particles of aquaponic solution, compared to the polyurethane sponge.