• Analytical Science and Technology
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• v.6 no.1
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• pp.29-37
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• 1993

Some new podands containing phenyl(B), benzyl(Bz), pyridine(Py), quinoline(Q) and naphthalene(Np) as end-groups, and oxygen(O) and sulfur(S) in ether chains as donor atoms have been synthesized. The univalent cation binding characteristics of these podands have been studied by NMR titration and solvent extraction. By NMR titration we have found that the most of podands form 1:1 complexes with $Ag^+$ ion. Especially, the substituted sulfur atoms in ether chains show the effects to enhance the stabilities. We also carried out the extractions of univalent cation picrates including alkaline metal, $Ag^+$, $Tl^+$ and $NH_4{^-}$ ions from aqueous to chloroform layer by using these podands. We found that the extractabilities of $Ag^+$ ion with the quinoline-containing podands such as, $Q_2O_4$, $Q_2O_5$ and $BQO_5$ were 86.8, 86.6 and 48.0% respectively, but the naphthalene-containing podands such as, $Np_2O_4$ and $Np_2O_5$ extracted quite small amount. Otherwise, in cases of $Bz_2O_3S_2$(89.4%), $B_2O_2S_2$(96.8%), $B_2O_3S_2$(58.9%), $Py_2O_2S_2$(58.8%), $Py_2O_3S_2$(42.1%), and $B_2O_4S$(15.0%), interestingly, $Bz_2O_3S_2$ which have sulfur atoms and benzyl groups showed the highest extraction selectivity for $Ag^+$ ion. This result seems due to not only the strong interaction of $Ag^+$ ion with sulfur donors according to the HSAB theory, but also the effective ${\pi}-{\pi}$ stacking interaction between two aromatic end-groups which is enhanced by the flexible methylene spacing group in benzyl groups instead of phenyl groups. The extraction coefficients gave the similar tendency as the extractabilities and the stabilities. From these results, it could be concluded that the predominant factor affected to extraction coefficients is the stabilities, which are strongly influenced by the structures of podands.

• Journal of The Korean Association For Science Education
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• v.41 no.3
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• pp.237-250
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• 2021

Teachers play a key role in designing a students' learning experience. Teachers are asked to interpret the context in which they are located and to adjust their practice to fit circumstantial needs based on their teacher agency. In this study, we explore the emergence of teacher agency in distance learning caused by COVID-19 and we analyze factors shaping the teacher agency. For this purpose, we interviewed six secondary science teachers who practiced distance learning in 2020. Semi-constructed interviews and their artifacts were collected and analyzed. This study shows that teacher agency is captured when they respond to circumstantial change and modify their practice to achieve their professional purpose or adjust their practice in space for maneuvering or keep their practice consistent. This study also analyzes the factors that affect the emergence of teacher agency in two dimensions. One is individual and the other is contextual. In the individual dimension, educational values shaped by his/her experiences and short/long-term goals for the future support the emergence of teacher agency. In the contextual dimension, there are collaborative and flexible culture shared by the community, co-operation within the teacher community, and material support. On the other hand, in the individual dimension, the teachers' sense of their role, and no reflection for own practice constrain the emergence of teacher agency, and in the contextual dimension, performativity discourse and strong requirement without guidance constrain the emergence of teacher agency. We suggest an effective lens for establishing a strategy that support teachers' professional practice and the emergence of teacher agency.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.616-624
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• 2020

International trade is one of the primary ways that non-native species spread worldwide. Korea and China are geographically close and have a large mutual trade volume. To investigate the population movement of the invasive whitefly(Bemisia tabaci Gennadius) between the two countries, we compared the biotype distribution, insecticidal response, and the TYLCV(tomato yellow leaf curl virus) viruliferous rate of local populations collected in 2019. Based on the mitochondrial DNA COI sequences of B. tabaci, only the Q biotype was found in all populations in Korea, whereas the B biotype (14.3%) and Q biotype (85.7%) were found in China. In the haplotype composition of the B. tabaci Q biotype, only the Q1 group[Q1H1(79.8%) and Q1H2(20.2%)] was observed in China, but the Q1 group [Q1H1(1.7%) and Q1H2(97.5%)] and the Q2 group(only one individual) were found in Korea. The Korean populations showed high mortality(more than 80%) from 15 commercial insecticides, but the Chinese populations showed significantly low mortality from eight insecticides. No TYLCV infections were observed in the Korean populations while the average TYLCV viruliferous rate was 21.4% in the Chinese populations. Taken together, the results suggest that the population structures of B. tabaci in the two countries are different and may have different immigration histories.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.3
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• pp.11-28
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• 2021

Due to its size and complex characteristics, it is not often to newly create a large park within an existing urban area. Also, there has been a lack of research on the planting design methodologies for a large park. This study aims to elucidate how ecological ideas can be applied to planting practice from a designer's perspective, and eventually suggest a planting design framework in the actual case, the Central Park in the City of Gwangju. This framework consists of spatial structure of planting area in order to connect and unite the separated green patches, to adapt to the changes of existing vegetation patterns, to maintain the visual continuity of landscape, and to organize the whole open space system. The framework can be provided for the spatial planning and planting design phase in which the landscape designer flexibly uses it with the design intentions as well as with an understanding of the physical, social, and aesthetic characteristics of the site. The significance of this approach is, first that it can maintain ecological and visual consistency of the both existing and introduced landscapes as a whole in spite of its intrinsic complexity and largeness, and second that it can help efficiently respond to the unexpected changes in the landscape. In the case study, comprehensive site analysis is conducted before developing the framework. In particular, wetlands and grasslands have been identified as potential wildlife habitat which critically determines the vegetation patterns of the green area. Accordingly, the lists of plant communities are presented along with the planting scheme for their shape, layout, and relations. The model of the plant community is developed responding to the structure of surrounding natural landscape. However, it is not designed to evolve to a specific plant community, but is rather a conceptual model of ecological potentials. Therefore, the application of the model has great flexibility by using other plant communities as an alternative as long as the characteristics of the communities are appropriate to the physical conditions. Even though this research provides valuable implications for landscape planning and design in the similar circumstances, there are several limitations to be overcome in the further research. First, there needs to be more sufficient field surveys on the wildlife habitats, which would help generate a more concrete planting model. Second, a landscape management plan should be included considering the condition of existing forest, in particular the afforested landscapes. Last, there is a lack of quantitative data for the models of some plant communities.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.1
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• pp.55-69
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• 2021

For the national economic development, the participation of women in the social and economic activities is crucial. The popularization of start-ups, digital transformation, and WEconomy trends have lowered the barriers to opportunities for women to start a business and provide an environment in which women can grow faster. This paper examines the significance and process of success of women entrepreneurs and the characteristics of innovation strategies and achievements by linking the recently changing business environment of a company, factors influencing the success of women entrepreneurship, and innovation activities. To this end, four companies' cases were analyzed in the fields of distribution/service and consumer products/services, which are areas of large investment among female startups. The result shows that women entrepreneurs recognize the meaning of success as creating and continuing to create a 'corporate value through establishing a trust relationship with customers' within the 'balance between personal life and work.' In terms of the business ecosystem, women entrepreneurs strive for 'business activities based on the win-win growth of consumers, producers and sellers' for success, and rather 'focus on the process with a problem-solving approach' rather than achieving performance-oriented goals. Also through excellent power of observation, flexibility, and execution power, women entrepreneurs conduct business by adapting to changing trends. In terms of innovation activities, the innovation strategy of women-led companies puts priority on 'creating the value customers want' and focuses on innovation in the 'customer-centric business model' rather than technological innovation. As such, women-led companies show several differentiated characteristics, which enable them to create corporate value and achieve sustainable growth. The barriers to challenges and opportunities for women to start a business have been lowered, and an ecosystem has been created for female startups to grow. But why are there still so few women entrepreneurs, and the answer to where we need to close these gaps is ultimately a close analysis and investigation of the field. We must present milestones for growth steps through the accumulation of case studies of women startups that have exited. In addition, women can stand as economic agents only when the policy targets are subdivided and specific approaches to child-rearing and childcare for women entrepreneurs must be taken. This paper expects to serve as basic data for follow-up studies and become the basis of research for women entrepreneurs to grow as economic agents.

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.49-66
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• 1969

Eri-silkworm is known as a tropical insect where as poly-voltine type in that area. It eats caster oil plant leaves which are cultivated as an every year cultivatable seed oil use in this country, even though it grows for many years in tropical countries. That is why, farmers have freedom for its cultivation in any year if they want. Therefore, eri-silkworm rearing service is flexible for its diet procurment as wish of farmer. The eri-cocoon price or economical fluctuation may be reactable for the rearing work not like as mulberry cocoon. Fortunately, it also eats cynthia tree leaves. Standing from such a easy condition, the authors have studied about this problem since 1963 to develope a culturing method of eri-silkworm rearing in this country and the authors brought out the matters to be produced as an industry scale. Here, the authors summarized their works of the results covering with thirty three work tables. The obtained results are as follows.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1060-1068
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• 2019

The physical fitness of the cadets of the Air Force Academy, which will protect the airspace of the Republic of Korea, is of paramount importance to fulfill the given mission. Therefore, the purpose of this study was to confirm the characteristics of body composition and physical fitness of female cadets of Air Force Academy and to verify their relationship with physical fitness according to body fat % level of total female cadets. To achieve the purpose of the study, 50 female cadets of the Korea Air Force Academy (1grade 13, 2grade 18, 3grade 9, 4grade 10) were measured in body composition (skeletal strength, body fat mass, body mass index, body fat %, abdominal obesity rate, basal metabolic rate) and physical fitness (muscle strength, muscular endurance, power, agility, flexibility and balance). One way ANOVA was performed for data processing to identify body composition and physical fitness characteristics by grade and to identify differences in physical fitness according to body fat rate levels. According to the study, the 1 grade was lower in body fat mass and body fat % among female cadets, the 2 grade was lower than the 3 and 4 grades, and the body mass index was lower than the third and fourth grades. Also, there was no difference in the physical fitness of the rest of the year. The intergroup physical fitness according to the body fat rate was higher than that of those with less than 20 percent of net worth and 25 percent to less than 25.1 percent to 30 percent, while those with less than 20 percent balance were higher than those with less than 25.1 to 30 percent. The results of this study showed differences in body composition by grade in female cadets, especially in power and balance according to body fat %. Therefore, female cadets of the Air Force Academy need to manage body fat to have the power and balance capability related to the airborne mission environment.

• Korean Journal of Plant Taxonomy
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• v.36 no.3
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• pp.163-187
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• 2006

Taxonomic studies were conducted to evaluate the interspecific relationships in Viola albida var. albida and its related taxa using seven populations for morphology, palynology and anatomy. Molecular phylogenetic studies were also examined in 28 populations including 19 Korean, four Chinese, two Japanese, one American population and two outgroups using nrITS, and 27 populations except V pinnata for trnL-F region of chloroplast DNA. Morphological differences was observed among seven populations of three species in leaf shape, but characters such as serrate number of leaf margins, petal size, pistil shape were showed overlap between populations. Pollen shape of seven populations was monad and grain shape on the polar axis was semi-angular. Morphology of aperture was tri-colporate, and the surface sculpturing was scabrate in rugulate. The grain shape of equatorial view of five populations was prolate whereas V albida var. taknhashii type 1 and V albida var. chaerophylloides type 3 were subprolate. The anatomical characters of rnidvein of leaf, petiole, peduncle, root were also described for the species. The stomatal apparatus of the leaves was observed only in abaxial surface, and the number of stoma per unit ($mm^2$) were abundant in incised than lobate or cleft margin of the leaves. The nrITS analysis shows that V. pinnata and V. dissecta was monophyletic and occupied a basal position in the V. albida var. albida and its related taxa. The other clade including infraspecific populations of V. albida, and V. eizanensis was paraphyletic. The trnL-F noncoding region analysis was similar to the ITS tree. According to the above observations in morphology, palynology, anatomy, and molecular phylogenetic analysis, the significant differences were not found except for leaf shape in Viola albida var. albida and its related taxa, therefore V. albida var. takanhashii and V. albida var. chaerophylloides were considered to be an infraspecific taxa of V. albida var. albida rather than an independent species, subvariety or variety of V. pinnata and V. dissecta.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.199-204
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• 2006

This study was conducted to investigate the quality characteristics of noodles prepared with the addition of nanofiltered (NF) powder of sunmul. Noodles were prepared with different levels $(0\%,\;1.5\%,\;3\%\;and\;5\%,\;w/w)$ of NF powder and physico-chemical properties were examined. Results of rapid visco analyzer showed that peak, trough, final viscosity and set back decreased as the NF powder level increased. The weight and volume of cooked noodles increased with the addition of NF powder. Turbidity of soup also increased as the amount of NF powder increased, indicating higher cooking loss. The color of wet and cooked noodles became greenish yellow as the NF powder level increased. Hardness, springiness, gumminess and brittleness of cooked noodles decreased with the increasing amount of NF powder. Results of sensory evaluation showed that noodles prepared with up to $3\%$ addition of NF powder was considered to be as acceptable as noodles prepared without NF powder.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.213-220
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• 1971

In order to investigate chemical components of edible marine algae in Korea, the present work is carried out with ten edible and two non-edible species of brown algae, collected from Cheju-island during October, 28-30 in 1970. Among the general components, water content is about 14-16% to dry weight and the crude protein about 16%, which are almost similar in content compared with several non-cultivate edible land plants. The content of crude fat is about 0.7-2.0%, and that of crude fiber about 3-8%, while the content of crude ash is 9.17-16.89%. The last one is more than two times in content compared with the land plants. The reducing sugar is about 0.27-2.49% in general. On the other hand, among the minerals Ca content is the most abundant, 1.73-2.51%, and the next is S, 1.0-1.8%. Mg and I are around 0.1-1%, while K and Na are about 1% in content. Among the micro-elements, Fe and Zn are about 0.01-0.03%, and Cu and Mn 0.001-0.005% in content. There is no special significant difference in chemical components between the edible and non-edible species of brown algae. Moreover, so far as the present investigation is concerned, there can be found no significant inter-species relationship on the taxonomical or phylogenetical points of view, considering their components.